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Anesthesia 2 – 3rd stage Anesthesia 2 Regional anaesthesia (spinal, epidural, nerve block)  Regional anesthesia is the use of local anesthetics to block sensations of pain from a large area of the body, such as an arm or leg or the abdomen.  Regional an...

Anesthesia 2 – 3rd stage Anesthesia 2 Regional anaesthesia (spinal, epidural, nerve block)  Regional anesthesia is the use of local anesthetics to block sensations of pain from a large area of the body, such as an arm or leg or the abdomen.  Regional anesthesia allows a procedure to be done on a region of the body without the patient being unconscious.  Regional anesthesia and analgesia, either alone or in combination with general anesthesia, has the potential to provide excellent operating conditions and prolonged postoperative pan relief.  The provision of pain relief that enables postoperative mobilization and early feeding may accelerate rehabilitation and return of normal function. Relative indications of regional anesthesia: 1) To avoid some of the dangers of general anesthesia, such as difficult tracheal intubation, severe respiratory failure, and when problems due to the use of muscle relaxant or general anesthetics are expected. 2) Patients who specifically request regional anesthesia. 3) To provide high - quality postoperative pain relief. 4) As part of a postoperative rehabilitation program to enable early return to function. Relative contraindications for regional anesthesia: 1) Uncooperative or restless patients. 2) Some psychiatric patients. Preparation before local anesthetic is injected: Before any local anesthetic is administrated the following should be available: 1) An indwelling intravenous cannula. 2) A tilting table or trolley. 3) Facilities of intermittent IPPV with oxygen. Page 1 of 83 Anesthesia 2 – 3rd stage 4) Patient monitoring, including ECG, noninvasive blood pressure, pulse oximetry and end - tidal carbon dioxide (in case of need for general anesthesia). 5) Suction equipment and catheters. 6) Syringes or ampoules of tranquilizers (eg. midazolam), induction agents (e.g., Propofol), muscle relaxants (e.g., Suxamethonium), atropine, and pressor agents such as ephedrine. 7) Crystalloid and colloid solutions for infusion. 8) Full resuscitation equipment and drugs, including a defibrillator. Major types of regional anesthesia include: A) Peripheral nerve blocks: A local anesthetic is injected near a specific nerve or bundle of nerves to block sensations of pain from the area of the body supplied by the nerve. Nerve blocks are most commonly used for surgery on the arms and hands, the legs and feet, the groin, or the face. Intravenous regional anesthesia – Bier’s block: Bier‟s block is one of the peripheral nerve block techniques performed on the body extremities, it is ideally suited to operations of the distal arm or leg (i.e., below the elbow or knee), such as reduction of a radial or ulna fracture. IVRA is useful for only short surgical procedures; performed in 40 minutes or less (the length of operating time is limited by tourniquet pain, which usually develops after 40 to 60 minutes First of all, the target region exsanguinated to force blood out of the extremity followed by the application of pneumatic single or double tourniquet inflated 100mmHg above the patient‟s systolic blood pressure to safely stop blood flow. The anesthetic agent is intravenously introduced into the limb and allowed to diffuse into the surrounding tissue while tourniquets retain the agent within the desired area. Page 2 of 83 Anesthesia 2 – 3rd stage Two intravenous cannulas should be placed, one for venous cannulation distal to the tourniquet and one for cannulation in a non-targeted arm to allow access to the circulation if required in the event of complications. The dose required in Bier‟s block is about 3 – 4 mg/ kg of 0.5% plain solution (without adrenaline) of lidocaine or prilocaine, while bupivacaine should never be used due to its cardiotoxicity (leading to ventricular arrhythmias and death). Contraindications: 1) Crush injury to the limb, IVRA may provoke further tissue damage secondary to hypoxia 2) Reynold's disease (intermittent arteriolar vasospasm of the distal limbs). 3) Sickle cell anemia. 4) Scleroderma. Ultrasound guided regional anesthesia (USGRA) Ultrasonography (US) as a means to guide peripheral nerve blockade (PNB) was first explored by anesthesiologists at the University of Vienna in the mid-1990s. Although radiologists had made use of ultrasound technology to guide needles for biopsy, the application of this imaging modality for PNB was novel at that time. The utility of ultrasound to facilitate a range regional anesthesia technique including brachial plexus and femoral blocks was demonstrated. A decade later, colleagues from the University of Toronto, Canada, Page 3 of 83 Anesthesia 2 – 3rd stage began to embrace this technology, further demonstrating its utility and describing in detail the sonoanatomy of the brachial plexus. The Transversus Abdominis Plane (TAP) Block is a local anaesthetic block used to provide analgesia to the anterior and lateral abdominal wall. It described an anatomical landmark technique and provided evidence of blockade to the mid/lower thoracic and upper lumbar spinal nerves as they travelled in the fascial plane between the transversus abdominis and internal oblique muscles. Later on an ultrasound-guided approach to the TAP block. INDICATIONS FOR TAP BLOCK The TAP block can be used as part of an analgesic regimen for abdominal surgery. Initial studies were able to demonstrate blocks extending from T7-L1 using bilateral injections. Subsequent studies have been unable to reproduce these findings with most studies achieving uppermost sensory levels around T9/10. This lower block is supported by findings in a cadaveric study, looking at spread of local anaesthetic after a single posterior TAP injection. It therefore sensible to recommend that the TAP block can only reliably be used for analgesia in surgery on the lower abdomen, for example: Hernia repair Open appendicectomy Caesarian section Total abdominal hysterectomy Radical prostatectomy Page 4 of 83 Anesthesia 2 – 3rd stage A local anesthetic is injected near the spinal cord and major nerves that enter the spinal cord to block sensations of pain from an entire region of the body, such as the lower abdomen, the hips, or the legs. Caudal block: It involves injection of local anesthetic into the epidural space through the sacral hiatus to obtain anesthesia of sacral and coccygeal nerve roots. It indicated for superficial operations such as skin grafting, perineal procedure, and lower limb surgery. Spinal (intradural) anesthesia: anatomy: The spinal cord usually ends at the level of L1 in adults and L3 in children. Page 5 of 83 Anesthesia 2 – 3rd stage Dural puncture above these levels is associated with a slight risk of damaging the spinal cord and is best avoided. An important landmark to remember is that a line joining the top of the iliac crests is at L4 to L4/5. Page 6 of 83 Anesthesia 2 – 3rd stage Page 7 of 83 Anesthesia 2 – 3rd stage Page 8 of 83 Anesthesia 2 – 3rd stage  Indications & Advantages  Surgeries of lower limbs, perineum, pelvis, abdomen It is ideal in Renal failure greater by two or three segments,  duration is shorter  Cardiac disease  Liver disease  Obstetric anaesthesia  Full stomach  Anatomic distortions of upper airway  TURP surgery Levels of block Sympathetic paralysis Sensory block Motor nerve blockade TECHNIQUE It is done in a similar way. But the local anesthetic is injected using a much smaller needle, directly into the cerebrospinal fluid that surrounds the spinal cord. The site in which the needle should be inserted in is between the third and fourth lumbar vertebrae. The area numbed first with a local anesthetic. Then the needle is guided into the spinal canal, and the anesthetic is injected. This is usually done without the use of a catheter. Spinal anesthesia numbs the body below and sometimes above the site of the injection. The person may not be able to move his or her legs until the anesthetic wears off. Page 9 of 83 Anesthesia 2 – 3rd stage  Factors Effecting Distribution  Site of injection  Shape of spinal column  Patient height  Angulation of needle  Volume of CSF  Characteristics of local anesthetic  Density  Specific gravity  Dose  Volume  Patient position (during & after) Cardiovascular Effects:  Blockade of Sympathetic Preganglionic Neurons  Send signals to both arteries and veins Page 10 of 83 Anesthesia 2 – 3rd stage  Predominant action is venodilation  Reduces:  Venous return  Stroke volume  Cardiac output  Blood pressure  T1-T4 Blockade  Causes unopposed vagal stimulation  Bradycardia  Associated with decrease venous return & cardioaccelerator fibers blockade  Decreased venous return to right atrium causes decreased stretch receptor response Hypotension:  Treatment  Best way to treat is physiologic not pharmacologic  Primary Treatment  Increase the cardiac preload  Large IV fluid bolus within 30 minutes prior to spinal placement, minimum 1 liter of crystalloids  Secondary Treatment  Pharmacologic  Ephedrine is more effective than Phenylephrine Page 11 of 83 Anesthesia 2 – 3rd stage Respiratory System:  Appropriate spinal blockade has little effect on ventilation  High Spinal  Decrease functional residual capacity (FRC)  Paralysis of abdominal muscles  Intercostal muscle paralysis interferes with coughing and clearing secretions  Apnea is due to hypo perfusion of respiratory center Complications: 1. Immediate complications - Hypotension - Bradycardia and Cardiac arrest. - High and Total spinal block leading to respiratory arrest. - Urinary retention. - Epidural hematoma, Bleeding. 2. Late complications -Post dural puncture headache (PDPH) -Backache - Nausea - Focal neurological deficit - Bacterial meningitis - Sixth Cranial nerve palsy Page 12 of 83 Anesthesia 2 – 3rd stage - Urinary retention Spinal headache:  More common in women ages 13-40  Larger needle size increase severity  Onset typically occurs first- or second-day post-op  Treatment:  Bed rest (remain lying flat in bed as this relieves pain)  Fluids (drink freely or IV fluid to maintain hydration)  Simple analgesia such as paracetamol, or aspirin or codeine may be helpful.  Caffeine containing drink  Blood patch Blood Patch:  Increase pressure of CSF by placing blood in epidural space  May do no more than two  95% success with first patch  Second patch may be done 24 hours after first Epidural (extradural) anesthesia: Epidural space: Potential space between the dura mater and ligament flavum Made up of vasculature, nerves, fat and lymphatic Page 13 of 83 Anesthesia 2 – 3rd stage Extends from foramen magnum to the sacrococcygeal ligament. Is segmented and not uniform in distribution The Bounds of the Epidural Space Anterior- posterior longitudinal ligament, Lateral- pedicles and intervertebral ligaments, Posterior- ligamentum flavum Epidural level (cervical ,thoracic, lumber, Caudal)  Widest at Level L2 (5-6mm)  Narrowest at Level C5 (1-1.5mm Distances from Skin to Epidural Space Average adult: 4-6cm (80%) Obese adult: up to 8cm Thin adult: 3cm Volume : 118ml Page 14 of 83 Anesthesia 2 – 3rd stage Local anaesthetic solutions are deposited in the peridural space between the dura mater and the periosteum lining the vertebral canal. The injected local anaesthetic solution produces analgesia by blocking conduction at the intradural spinal nerve roots. TECHNIQUE: It involves the insertion of a hollow needle and a small, flexible catheter into the space between the spinal column and outer membrane of the spinal cord (epidural space) in the middle or lower back. The area where the needle will be inserted is numbed with a local anesthetic. Then the needle is inserted and removed after the catheter has passed through it. Page 15 of 83 Anesthesia 2 – 3rd stage The catheter remains in place. The anesthetic medicine is injected into the catheter to numb the body above and below the point of injection as needed. The catheter is secured on the back so it can be used again if more medicine is needed. Test Dose: 1.5% Lido with Epi 1:200,000 1.Tachycardia (increase >30bpm over resting HR) 2.High blood pressure 3.Light headedness 4.Metallic taste in mouth 5.Ring in ears Page 16 of 83 Anesthesia 2 – 3rd stage 6.Facial numbness Note: if beta blocked will only see increase in BP not HR Testing for level of block If Sympathetic block occurs? Skin temperature sensation Changes in the skin temperature Sensory level: Pin prick using sterile needle Loss of touch is two dermatomes lower than pin prick Motor block Modified Bromage scale of onset of motor Block Central Neuraxial Blockade Preparation for central neuraxial blockade: 1) All equipment, drugs, I.V fluids and facilities that mentioned in the preparation to local anesthetic injection should be available. 2) Assessment, explanation, consent and examination of the patient. 3) Full asepsis and “no – touch” technique is essential; surgical scrub, gown, mask, gloves, hat, and a sterile field. Equipment should be prepared in advance and in a sterile manner. Page 17 of 83 Anesthesia 2 – 3rd stage 4) A sedative benzodiazepine should often help the patient to tolerate the procedure. 5) Ketamine 0.1 – 0.25 mg/ kg has been given when positioning causes pain (such as fractured hip). 6) If the patient heavily sedated or ill, he/ she should be positioned in the lateral position with his/ her back parallel to the edge of the table and knees and head fixed. 7) Many anesthetists find the sitting position easier than the lateral position, the patient is placed across the table or bed with their feet resting comfortably on a stool – the spine should be flexed with the chin pressed on to the sternum, and pillow on the knees gives helpful support on the arms. Contraindications to central neuraxial blockade: Page 18 of 83 Anesthesia 2 – 3rd stage Absolute: 1) Raised intracranial pressure. 2) Coagulopathy, blood dyscrasias or full anticoagulant therapy. 3) Skin sepsis. 4) Marked spinal deformity. 5) Hypovolaemia. 6) Patient refusal. Relative: Mildly impaired coagulation, the risk of spinal hematoma should be weighed against the benefits of avoiding general anesthesia in patients with patients with platelets less than 80 000/ ml. If coagulation is impaired, spinal anesthesia is should be preferred over epidural anesthesia because of the reduced risk of hematoma formation. Comparison between spinal anesthesia and epidural anesthesia Spinal anesthesia Epidural anesthesia 1) Drug delivered to the subarachnoid space 1) Drug delivered outside the dura (outside and into the CSF CSF) 2) Injected only below the 3rd lumber 2) May be given at cervical, thoracic, lumber vertebra to avoid piercing the spinal cord or sacral sites 3) smaller dose injected 3) larger dose injected 4) onset: 2 – 5 minutes for initial effect, 20 4) onset: 5 – 15 minutes for initial effect, 30 – minutes for maximum effect 45 minutes for maximum effect 5) cause a significant neuromuscular block 5) Doesn‟t cause a significant neuromuscular (muscle relaxation) block 6) Gives profound block of all motor and 6) Blocks a 'band' of nerve roots around the sensory function below the level of injection site of injection, with close-to normal function below the levels blocked. 7) almost always a one-shot only 7) an indwelling catheter may be placed that allows for repeated doses Page 19 of 83 Anesthesia 2 – 3rd stage Local anesthetics: There are many anesthetic drugs used for neuraxial block; lidocaine, bupivacaine, levobupivacaine, and ropivacaine. Doses are associated with the amount of the local anesthetic and the concentration of the solution, depends on age, body height and weight, type and duration of the surgery, as example; bupivacaine dosage that required for spinal (intradural) anesthesia ranges between 0.5 – 2 ml of 0.75% solution (approximately 4 – 15 mg), epidural dosage for adults ranged between 10 – 20 ml of 0.25%, 0.50%, 0.75% (25 – 150mg) Page 20 of 83 Anesthesia 2 – 3rd stage Renal Disease and Anesthesia Introduction Normal renal function is important for the excretion of anesthetics and medications, maintaining fluid and acid-base balance, and regulating hemoglobin levels in the perioperative period. The kidneys play a vital role in  Regulating the volume and composition of body fluids,  Eliminating toxins, and  Elaborating hormones, including renin, erythropoietin, and the active form of vitamin D Factors related to operative procedures and to anesthetic management frequently have a significant impact on kidney physiology and function and may lead to  Perioperative fluid overload,  Hypovolemia, and acute kidney injury, which are major causes of:  perioperative morbidity, mortality, extended hospital length of stay, and increased costs. Anatomy Kidneys are located in the posterior abdominal wall, with the 11th and 12th ribs and diaphragm placed posteriorly. It is 10 cm in length, 5 cm in width, and 3 cm in thickness. Page 21 of 83 Anesthesia 2 – 3rd stage Renal Circulation Renal function is intimately related to renal blood flow (RBF). In fact, the kidneys are the only organs for which oxygen consumption is determined by blood flow; the reverse is true in other organs. The combined blood flow through both kidneys normally accounts for 20% to 25% of total cardiac output. Approximately 80% of RBF normally goes to cortical nephrons, and only 10% to 15% goes to juxtamedullary nephrons. Autoregulation of RBF normally occurs between mean arterial blood pressures of 80- and 180-mm Hg and is principally due to intrinsic myogenic responses of afferent glomerular arterioles to blood pressure changes. Within these limits, RBF and GFR are kept relatively constant by afferent arteriolar vasoconstriction or vasodilation. Glomerular filtration generally ceases when mean systemic arterial pressure is less than 40 to 50 mm Hg. Functions of the kidney 1. Regulation of ions in the blood: Sodium, Potassium, Calcium, Chloride, Phosphate. 2. Regulation of blood volume: adjust the volume of blood or eliminate water in the urine. 3. Regulation of blood pH: regulate by excreting a variable amount of Hydrogen ions in the urine, conserving bicarbonate HCO3 ions. 4. Production of hormones: Calcitriol: calcium hemostasis. Erythropoietin: RBC production. Page 22 of 83 Anesthesia 2 – 3rd stage Renin: blood pressure control. 5. Excretion of Waste: Urea and creatinine. Ammonia and amino acid. Drugs Evaluating Kidney Function The underlying cause of impaired kidney function may be glomerular dysfunction, tubular dysfunction, or urinary tract obstruction. the traditional diagnosis of AKI, based upon serum creatinine and urine output, has been refined into an increase of serum creatinine of 0.3 mg/dL or more within 48 h or a 1.5-fold or greater increase in baseline within 7 days. Since AKI is a systemic disorder, it is important to recall that the kidney excretory function assessed via serum creatinine and urine output ignores endocrine, metabolic, and immunological kidney functions. SERUM CREATININE Creatine is a product of muscle metabolism that is nonenzymatically converted to creatinine. Daily creatinine production in most people is relatively constant and related to muscle mass, averaging 20 to 25 mg/kg in men and 15 to 20 mg/kg in women. Creatinine is then filtered (and to a minor extent secreted) but not reabsorbed in the kidneys. The rate of creatinine production and its volume of distribution is frequently abnormal in the critically ill patient, and a single serum creatinine measurement often will not accurately reflect GFR in the physiological disequilibrium of AKI. The normal serum creatinine concentration is 0.8 to 1.3 mg/dL in men and 0.6 to 1 mg/dL in women. Creatinine Clearance Creatinine clearance measurement is the most accurate method available for clinically assessing GFR. Although measurements are usually performed over 24 h, 2-h creatinine clearance determinations are reasonably accurate and more convenient to perform. Creatinine clearances less than 25 mL/min are indicative of overt kidney failure. Blood Urea Nitrogen: Creatinine Ratio Page 23 of 83 Anesthesia 2 – 3rd stage Low renal tubular flow rates enhance urea reabsorption but do not affect creatinine excretion. As a result, the ratio of serum BUN to serum creatinine increases to more than 10:1. Decreases in tubular flow can be caused by decreased kidney perfusion or obstruction of the urinary tract. BUN: creatinine ratios greater than 15:1 are therefore seen in volume depletion and in edematous disorders associated with decreased tubular flow (eg, congestive heart failure, cirrhosis, nephrotic syndrome) as well as in obstructive uropathies. Increases in protein catabolism can also increase this ratio. Effects of Anesthesia & Surgery on Kidney Function 1- Acute kidney injury Acute kidney injury (AKI) is a common and underappreciated perioperative problem, occurring in 1% to 5% of all hospitalized patients and in approximately 50% of all ICU patients. AKI is a systemic disorder that can include fluid and electrolyte derangements, respiratory failure, major cardiovascular events, weakened immunocompetence leading to infection and sepsis, altered mental status, hepatic dysfunction, and gastrointestinal hemorrhage. It is also a major cause of chronic kidney disease (CKD). Preoperative risk factors for perioperative AKI include preexisting kidney disease, hypertension, diabetes mellitus, liver disease, sepsis, trauma, hypovolemia, multiple myeloma, and age greater than 55 years. The risk of perioperative AKI is also increased by exposure to nephrotoxic agents such as nonsteroidal anti-inflammatory drugs (NSAIDs), radiocontrast agents, and antibiotics. The clinician must possess a thorough understanding of the risks of AKI, its differential diagnosis, and its evaluation strategy AKI is a major contributor to increased hospital length of stay, markedly increasing morbidity, mortality, and cost of care. Patients may develop AKI and kidney failure secondary to intrinsic kidney disease. Page 24 of 83 Anesthesia 2 – 3rd stage Risk factors for AKI in the perioperative setting include:  Preexisting kidney impairment  Diabetes mellitus  Cardiovascular disease  Hypovolemia  The use of potentially nephrotoxic medications by older adult patients. 1. Reversible decreases in RBF, GFR, urinary flow, and sodium excretion occur during both neuraxial and general anesthesia. 2. Such changes are usually less pronounced during neuraxial anesthesia. 3. Most of these changes are indirect and are mediated by autonomic and hormonal responses to surgery and anesthesia. 4. AKI is less likely to occur when an adequate intravascular volume and normal blood pressure are maintained. 5. There is no evidence that currently utilized vapor anesthetic agents cause AKI in humans. 2.Chronic Kidney Disease: CKD is defined as either kidney damage or a GFR less than 60 mL/min for 3 months or more. Kidney damage is defined as a pathologic abnormality or markers of damage including abnormalities of the blood or on urine or imaging studies. Page 25 of 83 Anesthesia 2 – 3rd stage Diagnosis of Chronic Renal Insufficiency Oliguria does not set in until late in the disease and is an unreliable marker of disease progression. fluid overload and concomitant cardiac disease and confirmed by laboratory testing. - Proteinuria & urinary sediment are also helpful in diagnosis Classification of Chronic Renal Disease: ❖ Stage 1: Kidney damage with normal or GFR (290 ml/min) ❖ Stage 2: Kidney damage with mild GFR (60-89 ml/min) ❖ Stage 3; Moderate GFR (30-59 ml/min) ❖ Stage 4: Severe GFR (15-29 ml/min) ❖ Stage 5: Kidney failure with GFR Causes of renal failure 1) Diabetes Mellitus 25% 2) Glomerulonephritis 14% 3) Hypertension 8% 4) Polycystic kidney disease 6% 5) Pyelonephritis 6% 6) Renal vascular disease 6% 7) Others 17% 8) Uncertain 15% Systemic effects of renal failure 1) Cardiovascular system: Left ventricular hypertrophy Atherosclerosis Hypertension 2) Respiratory system: Pulmonary edema 3) Metabolic acidosis 4) Coagulopathy 5) Autonomic neuropathy 6) Fluid and electrolyte: Page 26 of 83 Anesthesia 2 – 3rd stage Volume overload Hyperkalemia Altered Kidney Function & the Effects of Anesthetic Agents INTRAVENOUS AGENTS Propofol & Etomidate The pharmacokinetics of both propofol and etomidate are minimally affected by impaired kidney function. Decreased protein binding of etomidate in patients with hypoalbuminemia may enhance its pharmacological effects. Barbiturates Patients with kidney disease often exhibit increased sensitivity to barbiturates during induction, even though pharmacokinetic profiles appear to be unchanged. The mechanism appears to be an increase in free circulating barbiturate secondary to decreased protein binding. Acidosis may also favor a more rapid entry of these agents into the brain by increasing the nonionized fraction of the drug. Ketamine Ketamine pharmacokinetics are minimally altered by kidney disease. Some active hepatic metabolites are dependent on renal excretion and can potentially accumulate in kidney failure. Benzodiazepines Benzodiazepines undergo hepatic metabolism and conjugation prior to elimination in urine. Because they are highly protein bound, increased benzodiazepine sensitivity may be seen in patients with hypoalbuminemia. Diazepam and midazolam should be administered cautiously in the presence of kidney impairment because of the potential for the accumulation of active metabolites. Opioids Most opioids used in anesthetic practice (morphine, meperidine, fentanyl, sufentanil, and alfentanil) are inactivated by the liver; some of these metabolites are then Page 27 of 83 Anesthesia 2 – 3rd stage excreted in urine. Remifentanil pharmacokinetics are unaffected by kidney function due to rapid ester hydrolysis in blood. With the exception of morphine and meperidine, significant accumulation of active metabolites generally does not occur with these agents. Accumulation of morphine (morphine-6-glucuronide) and meperidine (normeperidine) metabolites may prolong respiratory depression in patients with kidney failure, and increased levels of normeperidine may promote seizure activity. The pharmacokinetics of the most commonly used opioid agonist–antagonists (butorphanol, nalbuphine, and buprenorphine) are unaffected by kidney failure. INHALATION AGENTS Volatile Agents Volatile anesthetic agents are ideal for patients with kidney disease because they are not dependent on the kidneys for elimination and they have minimal direct effects on kidney blood flow. Although patients with mild to moderate kidney impairment do not exhibit altered uptake or distribution, accelerated induction and emergence may be seen in severely anemic patients (hemoglobin 2 h) routinely leads to transient muscle dysfunction from ischemia and may produce rhabdomyolysis or permanent peripheral nerve damage. Tourniquet inflation has also been associated with increases in body temperature in pediatric patients undergoing lower extremity surgery. 7- bone cement: Cement implantation syndrome due to Systemic absorption of residual methylmethacrylate monomer can produce vasodilation and trigger platelet aggregation, microthrombus formation in the lungs, and cardiovascular instability. The clinical manifestations of bone cement implantation syndrome include A- Hypoxia (increased pulmonary shunt), B- Hypotension, Page 48 of 83 Anesthesia 2 – 3rd stage C- Arrhythmias (including heart block and sinus arrest), D- Pulmonary hypertension (increased pulmonary vascular resistance), and decreased cardiac output. Treatment strategies for this complication include A- Increasing inspired oxygen concentration prior to cementing, B- Maintain euvolemia, C- Creating a vent hole in the distal femur to relieve intramedullary pressure, D- Using a femoral component that does not require cement. 8.DVT (deep venous thrombosis) and PE(pulmonary embolism) are common, especially after hip surgery; and can cause morbidity and mortality following orthopedic operations on the pelvis and lower extremities. Risk factors of DVT and PE include A. Obesity, B. Age greater than 60 years, C. Procedures lasting more than 30 min, D. Use of a tourniquet, E. Lower extremity fracture. F. Immobilization for more than 4 days. Orthopedic surgery often requires the use of unusual positions, some of which carry risks of nerve damage, soft tissue ischemia, electrical and thermal injury and joint pain. Care must be taken in protecting areas at risk of injury. Forceful movement of the patient by the surgeon is often inevitable during orthopedic Page 49 of 83 Anesthesia 2 – 3rd stage surgery. When such movement occurs, it is advisable to re-check the patient‟s position ensuring that soft tissues, nerves, eyes, airway connections and venous access are safe. Although some procedures may be performed under regional anesthesia alone, long operations may result in significant discomfort related to posture. Some positions adopted during orthopedic surgery are associated with venous air embolism, which occurs when large veins are open to air, particularly, when venous pressure is low. These postures include the lateral position for hip surgery, the sitting position for shoulder surgery and the prone position for spinal surgery.  Hip replacement can be performed under general, spinal or epidural anaesthesia, and a combination of techniques is often used.  The advantages of regional techniques include: · Reduced blood loss, reducing the need for transfusion · Avoids effects of general anaesthesia on pulmonary function · Avoid intubation · Good early postoperative analgesia · Reduced incidence of postoperative venous thrombosis and pulmonary embolism  The advantages of general anaesthesia include: · Easier for patients that cannot tolerate lying flat · Safer in patients with fixed output states like aortic stenosis, where maintenance of normal sinus rhythm, heart rate and intravascular volume is critical. · Patient preference Page 50 of 83 Anesthesia 2 – 3rd stage  A simple THR is particularly amenable to spinal anaesthesia and this can be supplemented with sedation or general anesthesia.  Target-Controlled-Infusion (TCI) propofol is useful sedation for the lateral position, using facemask supplemental oxygen. Intermittent doses of midazolam, also can be used.  For the supine position in a patient who wishes to be asleep during surgery, consider an LMA with a light GA to maintain the airway.  The addition of intrathecal opioid helps cover the longer duration of surgery necessary for a more complex primary hip replacement.  It is a suitable technique for up to 3 hours of surgery. Alternatively, or for longer cases, a combined spinal/epidural technique can be used.  GA (rather than sedation) may be combined with an epidural for any complex primary operation because of the prolonged surgical time. An LMA, or endotracheal tube and IPPV, may be considered.  Intraoperative  Inserting a urinary catheter will help to monitor fluid balance. Page 51 of 83 Anesthesia 2 – 3rd stage  Aim to maintain blood pressure at an adequate level based on preoperative readings. In elderly patients with vascular disease hypotension should be treated immediately.  Intra-operative antibiotic prophylaxis will be required.  Ensure adequate IV loading prior to cementing of femoral component.  Hypotension can occur on pressurisation of the cement into the femur, usually due to vasodilatation and direct myocardial depression from the monomer.  The transient hypotension does not correlate with the level of monomer in the circulation, but with deficit in blood volume.  The surgeon usually prefers the patients to be placed on their bed in the supine position with the legs abducted using a pillow to prevent dislocation of the prosthesis.  Patients are usually mobilized at 24-48 hours and simple IM/ subcutaneous opioids with regular paracetamol or NSAIDs are usually sufficient for postoperative analgesia in a simple THR.  If an epidural has been inserted, a postoperative infusion can be used but needs to cease prior to mobilization. PCA is a suitable alternative if pain relief is needed for an extended period. ANESTHESIA FOR LAPAROSCOPIC SURGERY Introduction Laparoscopy is the visualisation of the abdominal cavity through an endoscope. The laparoscopic approach has become a standard of care for many abdominal surgical procedures. It is a minimally invasive procedure Eg: appendectomy, inguinal hernia surgery, upper abdomen surgery, gynaecological procedures, urological procedures. Advantages:  Minimizes surgical incision and stress response  Decreases postoperative pain and opioid requirements Page 52 of 83 Anesthesia 2 – 3rd stage  Earlier ambulation  Shorter hospital stays  Early return to normal activities and work  Earlier return of bowel function  Can be performed in wide range of patients  Reduces health costs Limitations  Reduced range of motion and instrument dexterity  Two-dimensional view of the operative field  Physiologic changes  Extreme positions  New complications SURGICAL TECHNIQUES  Intraperitoneal insufflation of CO2 to create pneumoperitoneum  Carbon dioxide is used because it is noncombustible and more soluble in blood Vs (N2O or Helium)  An abdominal wall lift system (gasless laparoscopy):  Avoids the cardiopulmonary effects of CO2 pneumoperitoneum  Very difficult in obese patients  Provides a tent like working space limited to specific quadrant  Increases operating times and surgical costs  The initial access necessary for CO2 insufflation could be achieved either through Page 53 of 83 Anesthesia 2 – 3rd stage  a blind insertion of a Veress needle  a trocar inserted under direct vision.  Upon confirmation of appropriate placement, a variable flow electronic insufflator that automatically terminates gas flow at a preset intraabdominal pressure (IAP) is used to achieve pneumoperitoneum.  It is standard of care to maintain the IAP below 15 mm Hg  A video laparoscope, inserted through the port, allows visualization of the operative field. PHYSIOLOGIC EFFECTS: Cardiovascular Effects The hemodynamic changes during laparoscopy are due to:  The mechanical and neuroendocrine effects of pneumoperitoneum  The effects of absorbed CO2  Patient positioning  Patient factors such as cardiopulmonary status and intravascular volume  The type of surgical procedure  These effects are:  Increased SVR and MAP  Variable change (increased or no change) in cardiac filling volumes  Variable change (decreased or no change) in cardiac index  Cardiac dysrhythmias (brady or tachycardia) PHYSIOLOGIC EFFECTS: Pulmonary Changes — Diaphragm elevated — Decreased lung volumes — Decreased lung compliance — Uneven gas distribution — Cephalad displacement of carina Page 54 of 83 Anesthesia 2 – 3rd stage PHYSIOLOGIC EFFECTS: Splanchnic, Renal, Cerebral and Intraocular: — Increased cerebral perfusion and intracranial pressure — Decreased splanchnic blood low — Reduced renal perfusion and urine output — Decreased femoral vein low — Increase in intraocular pressure ANESTHETIC MANAGEMENT: Preoperative Assessment — A full preoperative assessment should be carried out — Careful attention should be paid to the cardiovascular and respiratory systems — The probability of conversion to an open procedure should be considered when choosing the anaesthetic technique — Pneumoperitoneum is undesirable in patients with increased ICP and in patients with ventriculo peritoneal shunts — Glaucoma is a contraindication to laparoscopic pelvic procedures ANESTHETIC MANAGEMENT: Intra-op Management Page 55 of 83 Anesthesia 2 – 3rd stage — Choice of Anesthesia — Regional anesthesia — Shorter laparoscopic procedures, such as diagnostic laparoscopy, which requires lower IAP and minimal head down tilt — General anesthesia — Balanced general anesthesia with tracheal intubation and mechanical ventilation with acceptance of higher end tidal carbon dioxide levels remains the best practice for minimally invasive surgical procedures. — Airway and Induction — Placement of a cuffed oral tracheal tube (COTT), neuromuscular relaxation, and positive pressure ventilation. — Bag and mask ventilation before intubation should be minimized to avoid gastric distension and the insertion of a nasogastric tube may be required — Use of LMA is controversial due to increased risk of aspiration and difficulties encountered when trying to maintain gas transfer while delivering the higher airway pressure required during pneumoperitoneum Page 56 of 83 Anesthesia 2 – 3rd stage — Propofol is considered the sedative–hypnotic drug of choice for induction of anesthesia — Maintenance of Anesthesia — Best with newer inhaled anesthetics — Ease of titratability — Exert some neuromuscular blocking effect — Provide faster emergence as compared to TIVA — Nitrous Oxide — Has amnestic and analgesic properties, as well as it reduces the requirements of inhaled and intravenous anesthetic drugs and facilitate recovery. — However, its use during laparoscopic procedures has been controversial as a result of concerns regarding its ability to diffuse into bowel lumen, causing distension and impaired surgical access as well as increased PONV — Analgesia — Opioids remain an important component of a balanced general anesthetic technique — But opioids should be used sparingly because of concerns of opioid related adverse effects — The use of regional techniques such as subdural, epidural, and transversus abdominis plane block, can be utilized as opiate-sparing techniques, particularly in laparoscopic techniques where larger incisions are required. — Wound infiltration with local anesthetic and intraperitoneal levobupivacaine reduces postoperative pain and opiate requirements. — Dexamethasone has also been suggested before induction to reduce subsequent opiate analgesia requirements — Mechanical Ventilation — Minute ventilation needs to be increased by 20% to 30% Page 57 of 83 Anesthesia 2 – 3rd stage — Lung protective ventilation — Recruitment maneuvers are beneicial and should be applied, particularly before and after a laparoscopic procedure. — Avoid hyperventilation (hypocapnia) — Acceptance of higher ETCO2 levels — Fluid Management — Remains one of the most controversial topics in perioperative management. — Maintenance of optimal intravascular volume or cardiac filling is critical in improving perioperative outcomes — Intraoperative fluid therapy should be specific to patient characteristics and the type of surgical procedure. — Traditional indicators used to guide fluid therapy (e.g., HR, BP, CVPs, and urine output) are not reliable. — Dynamic indicators, such as stroke volume or systolic or pulse pressure variation, are preferred — Nausea and Vomiting Prevention — Patients undergoing laparoscopic surgery are at a greater risk for PONV — Aggressive multimodal antiemetic prophylaxis is necessary in this high-risk population. — Dexamethasone at induction and 5-HT3 antagonists at the end of surgery — Optimal hydration, minimal opioid use, and aggressive pain control ANESTHETIC MANAGEMENT: Postoperative Considerations — Pain — Compared to open surgical procedures, pain after laparoscopic procedures is considered to be less intense and of shorter duration. Page 58 of 83 Anesthesia 2 – 3rd stage — Pain will usually be maximal during the first 2 h post-procedure and a prolonged duration of significant discomfort is rare — Postoperative shoulder-tip pain after laparoscopic surgery is common but may be reduced if the surgeon expels as much gas from the peritoneal cavity as possible — Optimal pain therapy for patients undergoing laparoscopic includes the use of multimodal analgesia techniques. — Pulmonary — Many studies report a lower incidence of pulmonary complications after laparoscopic approach as compared with open procedures. — In patients with significant respiratory dysfunction and restricted CO2 clearance, impaired postoperative ventilation from residual anesthetics and neuromuscular blockade in the immediate postoperative period may delay removal of absorbed CO2 and cause significant hypercapnia. — Venous thrombosis — Increased IAP and reverse Trendelenburg position have been reported to cause venous stasis that could increase the potential for deep vein thrombosis and pulmonary embolism INTRAOPERTIVE COMPLICATIONS — Those related to creation CO2 pneumoperitoneum — Surgical instrumentation — Patient positioning INTRAOPERTIVE COMPLICATIONS: Hemodynamic Complications — Bradyarrhythmias — attributed to increased vagal tone following peritoneal stretching — Tachyarrhythmias Page 59 of 83 Anesthesia 2 – 3rd stage — may be due to hypercapnia as a result of intraperitoneal CO2 insufflation. — Alterations in arterial blood pressure — Although rare, acute cardiovascular collapse can occur — Treatment of Hemodynamic complications — Confirm that the IAP has not exceeded 15 mm Hg — Rule out vascular injuries — Supportive therapy including — Reduction in anesthetics, — Fluid administration, and — Pharmacologic interventions INTRAOPERTIVE COMPLICATIONS: Pulmonary Complications — Hypoxemia — Patient related factors — Low inspired oxygen concentrations — Hypoventilation — Ventilation–perfusion mismatch — Endobronchial intubation — Atelectasis — Capno(pneumo)thorax — Pulmonary embolization — Reduced cardiac output — Anemia — Hypercarbia Page 60 of 83 Anesthesia 2 – 3rd stage — Increased CO2 absorption — Decreased alveolar ventilation — Increased carbon dioxide production — Obesity, malignant hyperthermia, fever, thyrotoxicosis — Rebreathing of carbon dioxide — Defective carbon dioxide absorber — Malfunctioning valves INTRAOPERTIVE COMPLICATIONS: Cardiopulmonary Complications — Prevention — Use lower intraabdominal pressure (10–12 mm Hg) — Limit position change — Early use of vasodilators and betablockade to control hypertension — Monitoring — Arterial line for continuous blood pressure — Hemodynamic monitoring using pulse contour analysis — Transesophageal echocardiography INTRAOPERTIVE COMPLICATIONS: Subcutaneous Emphysema — Can occur from inadvertent extraperitoneal insufflation in the subcutaneous, preperitoneal, or retroperitoneal tissue — Can involve the abdomen, chest, neck, and groin. — The CO2 can track to the thorax a mediastinum, thereby resulting in capnothorax or capnomediastinum — Predictors of subcutaneous emphysema include Page 61 of 83 Anesthesia 2 – 3rd stage — operative time of >200 minutes and — use of six or more surgical ports — In most cases, no specific intervention is required, and the subcutaneous emphysema resolves soon after the abdomen is deflated. INTRAOPERTIVE COMPLICATIONS: Capnothorax: — Rare, it is a potentially life-threatening complication — It is most common in procedures near the diaphragm — Causes — Inadvertent peritoneal breach — Misdirected Veress needle — Gas tracked through facial planes from the neck and thorax into the mediastinum and pleural space — Passage of gas through the pleuroperitoneal hiatus — Passage of gas through congenital defects (foramen of Morgagni) — Diagnosis — High index of suspicion — Increased ETCO2 and reduced ETCO2 with hypotension — Decreased oxygen saturation — Increased peak airway pressures — Hypotension — Unequal chest expansion and air entry — Bulging of hemidiaphragm seen through the endoscope — Conirmed on thoracic ultrasound and/or chest xray — Management: Page 62 of 83 Anesthesia 2 – 3rd stage — Stop surgery and deflate the pneumoperitoneum — Continue supportive treatment with hyperventilation and positive end expiratory pressure — Treat according to the severity of cardiopulmonary compromise: — Minimal compromise—treat conservatively with close observation — Moderate to severe compromise—place intercostal cannula or temporary drain — Reaccumulation of capnothorax—place chest drain INTRAOPERTIVE COMPLICATIONS: Hypothermia — The incidence of hypothermia during laparoscopic procedures is similar to that of open abdominal operations. — Heat loss during laparoscopy occurs mainly by convection — Dry CO2 exiting the cylinder at 21°C and being insufflated into a peritoneal cavity with a large surface area. — Therefore, heating and humidifying CO2 to a physiologic condition has been proposed, particularly in prolonged surgical procedures INTRAOPERTIVE COMPLICATIONS: Related with Positioning — Laparoscopic surgery often involves the extremes of the Trendelenburg or reverse Trendelenburg position with significant physiological effects. — Trendelenburg position may lead to — Facial, pharyngeal, and laryngeal edema, which might lead to upper airway obstruction including laryngospasm. — Ischemic optic neuropathy and postoperative blindness — Brachial plexus injury Page 63 of 83 Anesthesia 2 – 3rd stage — 'Well leg compartment syndrome’ is a rare syndrome induced by the combination of impaired arterial perfusion to raised lower limbs, compression of venous vessels by lower limbs supports, and reduced femoral venous drainage due to the pneumoperitoneum. — In the reverse Trendelenburg position, the extreme ‘head-up’ posture results in reduced venous return, leading to hypotension and potentially myocardial and cerebral ischemia INTRAOPERTIVE COMPLICATIONS: Complications from surgical instrumentation — Injury of major intraabdominal vessels (i.e., aorta, common iliac vessels, or inferior vena cava) — Uncontrollable hemorrhage requires immediate conversion to an open procedure to control bleeding and repair the vascular injury. — Gastrointestinal tract perforations, hepatic and splenic tears, and mesenteric lacerations. — Bladder or ureter injury — Bladder injury may be suspected by sudden deflation of the abdomen, pneumaturia (gas bubbles in the urinary bag), and hematuria. — Prevention — Placement of the Veress needle and trocars using a minilaparotomy approach — Stomach injuries can be reduced by gastric decompression prior to surgery — Bladder decompression Laparoscopic Procedures During Pregnancy — Laparoscopy can be safely performed during any trimester of pregnancy when operation is indicated — Gravid patients beyond the first trimester should be placed in the left lateral decubitus position or partial left lateral decubitus position to minimize compression of the vena cava Page 64 of 83 Anesthesia 2 – 3rd stage — CO2 insufflation of 10-15 mmHg can be safely used for laparoscopy in the pregnant patient. The level of insufflation pressure should be adjusted to the patient’s physiology — Intraoperative and postoperative pneumatic compression devices and early postoperative ambulation are recommended prophylaxis for deep venous thrombosis in the gravid patient — Fetal heart monitoring of a fetus considered viable should occur preoperatively and postoperatively in the setting of urgent abdominal surgery during pregnancy — Tocolytics should not be used prophylactically in pregnant women undergoing surgery but should be considered perioperatively when signs of preterm labor are present REFERENCES — Clinical Anesthesia, Barash 7th ed — Anaesthesia for Laparoscopic Surgery, Paul Hayden, 2011 (BJA) — Anaesthetic Considerations During Laparoscopic Surgery, Martín-Cancho — Society of American Gastrointestinal and Endoscopic Surgeons THANKS ANAESTHESIA FOR DAY CASE SURGERY Introduction The definition of day surgery in Great Britain and Ireland is clear; the patient is admitted and discharged on the same day, with day surgery as the intended management. The term „23-h stay‟ should be avoided; this is used in the United States healthcare system, but in the UK is counted as inpatient care and should not be confused with day surgery. Despite these advances, the overall rates of day surgery remain variable across the UK. The target that 75% of elective surgery should be performed as day cases remains in place , but minimally invasive surgery is now well established, allowing more procedures to be performed as day surgery and even greater rates should be possible. Page 65 of 83 Anesthesia 2 – 3rd stage There was a major effort to promote day surgery at the start of the millennium and recent drives to reduce length of stay and improve the quality of postoperative recovery have ensured that day surgery principles are fundamental to modern patient care. Shortened hospital stay and earlier mobilisation also reduces the risk of hospital-acquired infections and venous thromboembolism. Selection of patients Patients may be referred for day surgery from outpatient clinics, emergency departments or primary care. Advances in surgical and anaesthetic techniques, as well as published evidence of successful outcomes in patients with multiple comorbidities, have changed the emphasis on day surgery patient selection. Patient assessment for day surgery falls into three main categories: social, medical and surgical. Social factors The patient must understand the planned procedure and postoperative care and give informed consent to day surgery. Traditional criteria for day surgery discharge included the presence of a carer for 24 h postoperatively. This is now being re-evaluated and it is recognized that for some minor procedures 24-h care postoperatively may be an excessive requirement, whereas for complex surgery it may be insufficient. For example, a patient who has undergone a hysterectomy as a day case is likely to require care to support activities of daily living for longer than someone who has undergone a hysteroscopy. It is essential that, following procedures under general or regional anesthesia, a responsible adult should escort the patient home; however, it may not always be essential for a carer to remain for the full 24-h period. Medical factors Fitness for a procedure should relate to the patient's functional status as determined at pre- anaesthetic assessment, and not by ASA physical status, age or body mass index. Patients with a stable chronic disease such as diabetes are often better managed as day cases because there is minimal disruption to their daily routine. The only patients routinely not included in day surgery are those with unstable medical conditions. Obesity itself is not a contraindication to day surgery, as morbidly obese patients can be safely managed by experts, provided appropriate resources are available. This includes factoring in additional time for anaesthesia and surgery as well as the presence of skilled assistants and equipment. Surgical factors Page 66 of 83 Anesthesia 2 – 3rd stage The procedure should not carry a significant risk of serious postoperative complications requiring immediate medical attention, for example, haemorrhage or cardiovascular instability. Postoperative symptoms (such as pain and nausea) must be controllable by the use of a combination of oral medication and local anaesthetic techniques. The procedure should not prohibit the patient from resuming oral intake within a few hours of the end of surgery. Patients should be able to mobilize before discharge, for example, walking with an arm in plaster, but if full mobilization is not possible, appropriate venous thromboembolism prophylaxis should be instituted and maintained. pre-operative preparation pre-operative preparation has three essential components: 1. To educate patients and carers regarding day surgery pathways 2. To impart information regarding planned procedures and postoperative care to help patients make informed decisions; important information should be provided in writing 3. To identify medical risk factors, promote health and optimize the patient's condition Day surgery for urgent procedures Patients presenting with acute conditions requiring urgent surgery can be efficiently and effectively treated as day cases via a semi-elective pathway. After initial assessment, many patients can be discharged home and return for surgery at an appropriate time, either on a day-case list or as a scheduled patient on an operating list, whereas others can be immediately transferred to the day surgery service. This reduces the likelihood of repeated postponement of surgery due to prioritization of other cases. A robust day surgery process is key to the success of this service. Table 1. Types of urgent surgery suitable for day case procedures Page 67 of 83 Anesthesia 2 – 3rd stage Anesthetic management Day surgery anesthesia should be a consultant-led service. However, as day surgery becomes the norm for elective surgery, this requires appropriate training and provision of senior cover, especially in stand-alone units. Staff grade and associate specialist anesthetists who have an interest in day surgery should be encouraged to develop this as a specialist interest and take an important role in the management of the unit. National guidelines for patient monitoring and assistance for the anesthetist should be followed. Anesthetic techniques should ensure minimum stress and maximum comfort for the patient and should take into consideration the risks and benefits of the individual technique. Analgesia is paramount and must be long acting, but, as morbidity such as nausea and vomiting must be minimized, the indiscriminate use of opioids is discouraged (particularly morphine). Prophylactic oral analgesia with long-acting nonsteroidal anti-inflammatory drugs (NSAIDs) should be given to all patients, unless contraindicated. For certain procedures (e.g., laparoscopic cholecystectomy), there is evidence that standardized an aesthetic protocols or techniques improve outcome. Anesthetists should adhere to such clinical guidelines where they exist. Although early mobilization is beneficial, extending the range and complexity of day surgery Page 68 of 83 Anesthesia 2 – 3rd stage procedures may increase the risk of venous thromboembolism. National guidelines for venous thromboembolism risk assessment and prophylaxis should be followed. There should be policies for the management of postoperative nausea and vomiting (PONV) and discharge analgesia. Prophylactic anti-emetics are recommended in patients with a history of PONV, motion sickness and those undergoing certain procedures such as laparoscopic sterilization/cholecystectomy or tonsillectomy. Routine use of intravenous (i.e.) fluids and maintenance of body temperature can enhance the patient's feeling of well-being and further reduce PONV. Regional anesthesia Local infiltration and nerve blocks can provide excellent anesthesia and pain relief after day surgery. Patients may safely be discharged home with residual motor or sensory blockade, provided the limb is protected and appropriate support is available for the patient at home. The expected duration of the blockade should be explained and the patient should receive written instructions as to their conduct until normal power and sensation return. Infusions of local anesthetics may also have a role. The use of ultrasound guidance continues to expand the role of regional anesthesia in day surgery, enabling more accurate local an aesthetic placement, reducing the total dose administered and supporting the development of regional an aesthetic operating list. Use of a „block room‟ improves efficiency and allows confirmation of adequate nerve blockade before surgery commences. Spinal anesthesia has become accepted for use in day surgery. Appropriate spinal anaesthetic dosing targeted to surgical site, for example, lateral for a unilateral knee arthroscopy or sitting for perianal procedures, can minimize side-effects such as hypotension and prolonged motor blockade. Postoperative recovery and discharge Recovery from anaesthesia and surgery can be divided into three phases: First-stage recovery lasts until the patient is awake, protective airway reflexes have returned and pain is controlled. This should be undertaken in a recovery area with appropriate facilities and staffing. Use of modern drugs and techniques may allow early recovery to be complete by the time the patient leaves the operating theatre, and some patients can bypass the first stage. Most patients who undergo surgery with a local or regional anaesthetic block can be fast-tracked in this manner. Second-stage recovery is from when the patient steps off the trolley and ends when the patient is ready for discharge from hospital. This should take place in an area adjacent to the day surgery theatre and should be equipped and staffed to deal with common postoperative Page 69 of 83 Anesthesia 2 – 3rd stage problems (e.g. PONV, pain) as well as emergencies (haemorrhage, cardiovascular events). The anaesthetist and surgeon should be contactable to deal with problems. Patients and their carers should be provided with written information that includes warning signs of possible complications and when to seek help. Protocols should exist for the management of patients who require unscheduled admission, especially in a stand-alone unit. Late recovery ends when the patient has made a full physiological and psychological recovery from the procedure. This may take several weeks or months and is beyond the scope of these guidelines. NON-OPERATING ROOM ANAESTHESIA (NORA) Introduction  Some terms;  Nonoperating room anesthesia (NORA)  Anesthesia at remote location  Outpatient anesthesia  Office-based anesthesia (OBA)  Importance;  Number of NORA activities have increased rapidly (CT, MRI, neuroradiologic procedure or electroconvulsive therapy)  More Complex of the procedure, and situation and patients  Encompasses all sedation and anaesthesia provided by anesthesiology services outside of the operating room environment.  Area remote from main operating room  Radiology Department  Endoscopy suites  MRI  Dental Clinics Page 70 of 83 Anesthesia 2 – 3rd stage Special problem of NORA  Limited working place, limited access to the patient,  Electrical interference with monitors and phones, lighting and temperature inadequacy,  Use outdated, old equipment  Less familiar with the management of patients  Lack of skilled personnel, drugs and supports Page 71 of 83 Anesthesia 2 – 3rd stage Three step approaches to NORA Patient Anesthetis t Procedure environmen t 1. Patients  Most Patients tend to be older. (>50 yrs)  receive monitored anesthesia care (MAC) or sedation  Children commonly require sedation or anesthesia for diagnostic and therapeutic procedures.  thorough preanesthetic assessment, standard preanesthetic care.  sound anesthetic plan with appropriate level of monitoring and appropriate postanesthetic care. Patient factors requiring Sedation or Anesthesia for Nonoperating Room  Claustrophobia  Anxiety  Cerebral palsy  Developmental delay  Learning difficulties  Seizures  Movement disorders  Pain Page 72 of 83 Anesthesia 2 – 3rd stage  Acute trauma, with unstable cardiovascular, respiratory or neurological function  Children below 10 years old. 2. Procedures  Nature of the procedure, including patient position, grade of painful procedure, and its duration.  Optimum anesthesia plan provides safe patient care and facilitates the procedure.  Discussion with proceduralist for emergencies and adverse outcomes COMMON NONOPERATING ROOM ANESTHESIA PROCEDURES Radiologic imaging  Computed tomography (CT)  Magnetic resonance imaging (MRI)  Positron emission tomography (PET)  Various vascular imaging, stenting, and embolization procedures  Radiofrequency ablation (RFA)  Transjugular intrahepatic portosystemic shunt (TIPS) Diagnostic and therapeutic interventional radiology  Occlusive (“closing”) procedures: o Embolization of cerebral aneurysm/AVM/vascular tumors  Opening procedures: o Angioplasty/stenting/thrombolysis in stroke cerebral atherosclerosis or cerebral vasospasm Radiotherapy  Radiation therapy  Intraoperative radiotherapy Page 73 of 83 Anesthesia 2 – 3rd stage Diagnostic and therapeutic interventional cardiology Cardiac catheterization laboratory  Diagnostic cardiac catheterization  Percutaneous coronary interventions (PCI)  Interventional techniques for management of structural heart disease (Transcatheter aortic valve implantation [TAVI])  Placement of left ventricular cardiac assist devices for hemodynamic support Electrophysiology laboratory (EPL)  Electrophysiology studies and radiofrequency ablation  Implantation of biventricular pacing systems and cardioverter defibrillators  Cardioversion and transesophageal echocardiography Other Procedures Diagnostic and therapeutic interventional gastroenterology  Upper gastroenterology endoscopy  Esophageal dilatation or stenting  Percutaneous endoscopic gastrostomy tube placement  Endoscopic retrograde cholangiopancreatography (ERCP)  Colonoscopy  Liver biopsy Psychiatry  Electroconvulsive therapy (ECT) Dentistry  Dental extractions  Restorative dentistry ASA guidelines for non-operating room anesthesia locations Page 74 of 83 Anesthesia 2 – 3rd stage  Reliable O2 source with backup supply  Suction apparatus  Waste gas scavenging  Self-inflating resuscitation bag.  Adequate monitoring equipments  Safe electrical outlets for emergency power supply  Adequate illumination, battery backup  Sufficient space for anaesthesia personnel, equipment  Emergency cart, defibrillator, drugs, etc  Reliable means for two-way communication  Applicable facility, safety codes met  Appropriate postanaesthetic management. Patient Transfer  Sick, unstable patients are transferred back and forth  between ICU, OR and NOR locations for imaging, therapeutic, or diagnostic procedures.  Skilled personnel to evaluate, monitor and support he patient medical condition.  Portable ventilators and adequate supplies of oxygen  Manual self-inflating bag  Anesthetic and emergency drugs, equipment for intubation or intubation, portable suctions Table 1 Ingested Material Minimum Fasting Period (hours) Clear liquids: water, fruit juices without pulp, carbonated beverages, 2 clear tea, black coffee Page 75 of 83 Anesthesia 2 – 3rd stage Breast milk 4 Infant formula 6 Nonhuman milk: because nonhuman milk is similar to solids in 6 gastric emptying time, the amount ingested must be considered when determining an appropriate fasting period Light meal: a light meal typically consists of toast and clear liquids. 6 Meals that include fried or fatty foods or meat may prolong gastric emptying time; both the amount and type of foods ingested must be considered when determining an appropriate fasting period Anesthetic technique  General anesthesia: tracheal intubation or LMA best prevention of motion invasive, time and resource consuming, atelectasis  Sedation/analgesia: less invasive, cost and time saving high rate of failure, high airway and respiratory depression  No anesthesia Conscious sedation versus monitored anesthesia care Conscious sedation: a medically controlled state of depressed consciousness that allows protective reflexes to be maintained and retains the patient's ability to maintain a patent airway and to respond appropriately to physical and verbal stimulation. MAC: an anesthesiologist provides specific anesthesia services to particular patients with local or no anesthesia who undergoing a planned procedure. Page 76 of 83 Anesthesia 2 – 3rd stage Definition of general anesthesia and levels of sedation/Analgesia Table 2: Levels of Sedation Factors Minimal Moderate Deep Sedation General Anesthesia Sedation Sedation/Analgesia Responsiveness Normal response Purposeful response to Purposeful Unarousable even to verbal verbal or tactile response to with painful stimulation stimulation repeated or stimulus painful stimulation Airway Unaffected No intervention required Intervention Intervention often may be required required Spontaneous Unaffected Adequate May be Frequently Ventilation inadequate inadequate Cardiovascular Unaffected Usually maintained Usually May be impaired Function maintained Some may add a fifth state to these classifications, that is; dissociative anesthesia provided by ketamine, which causes analgesia and amnesia without loss of airway protective reflexes or cardiopulmonary stability. Environmental consideration for NORA X ray & Fluoroscopy  C arm moves back & forth takes large space &means of dislodging IV and ETT.  so, limit the time of exposure to radiation  increase the distance from source or radiation.  (> or < according to inverse square of distance from source)  use protective shielding Anesthesia for CT  Less complex  Use standard monitoring  Less anesthetic time  Higher levels of radiation exposure Contrast media Page 77 of 83 Anesthesia 2 – 3rd stage  Are iodinated compounds  MRI contrast are ionic & nonionic.  chelated metal containing gadolinium, iron, manganese. Allergic reaction  History  Symptoms: skin reactions, airway obstruction, angioedema, and cardiovascular collapse.  Treatment: corticosteroids, H1 and H2 blockers. Oxygen, epinephrine, β2-agonists, and intubation, IV fluids  Prevention: corticosteroids  Renal (increase S. Creatinine of 0.5mg/dl or 25% from baseline within 48 hrs to 72 hrs.)  CIN (contrast induced nephropathy) Risk factor for CIN  Renal disease  Prior renal surgery  Proteinuria  DM  HTN  Gout Magnetic Resonance Imaging  a noninvasive diagnostic technique that uses magnetic properties of atomic nuclei  to produce high-resolution, multiplanar cross-sectional images of the body.  Ferromagnetic materials should be excluded from the area of magnet.  Implantable medical devices: pacemakers, vascular clips, automatic implantable cardioverter-defribillators, mechanical heart valves. Anesthesia for MRI  High magnetic field  Need specialized compatible equipment  Radiofrequency noise  Metallic implants or implanted devices Patients with implanted pacemakers, ICDs, or pulmonary artery catheters may not have MRI scans. Electroconvulsive therapy (ECT)  Objectives: treat major depression, no responded to medications, suicidal.  Periods: 6 to 12 treatments over 2 to 4 weeks Page 78 of 83 Anesthesia 2 – 3rd stage  Anesthetic goals 1. amnesia and rapid recover 2. Prevent damage 3. Control hemodynamic response. 4. Avoid interference with initiation and duration of induced seizure. 5. absolute contraindication: intracranial hypertension Choice of anesthetic technique depends upon  patient’s comorbidities,  duration,  practioner preference and  patient requirements.  Deep sedation or  GA with intubation or supraglottic airways.  Sedation with oral route benzodiazepines or as intravenous sedation or MAC.  Small infants: ” feed, wrap, and scan”  Oral chloral hydrate: 80-100mg/kg 30-60 min before procedure.  Rectally administered barbiturates or  General anesthesia with propofol, ketamine or inhaled anesthetics Complication of NORA Minor Complications (in order of frequency)  Postoperative nausea and vomiting  Inadequate postoperative pain control  Hemodynamic instability  Minor neurologic complications such as postdural puncture headache (cardiology and radiologic locations)  Minor respiratory complications (cardiology and radiologic locations)  Complications related to central/intravenous lines (cardiology locations)  Need for opioid reversal (cardiology and radiologic locations) Major Complications  Unintended patient awareness (gastroenterological locations)  Anaphylaxis (radiology procedures and cardiology locations)  Need for upgrade of care  Serious hemodynamic instability Page 79 of 83 Anesthesia 2 – 3rd stage  Respiratory complications  Need for resuscitation  Central and peripheral nervous system injury (radiology procedures and cardiology locations)  Vascular access-related complications (radiology procedures and cardiology locations)  Wrong patient/wrong site (radiology procedures and cardiology locations)  Fall or burn (radiology procedures and cardiology locations) Discharge criteria 1. Cardiovascular function and airway patency are satisfactory and stable. 2. The patient is easily arousable, and protective reflexes are intact. 3. The patient can talk (if age appropriate) 4. The patient can sit up (if age appropriate) 5. Adequate state of hydration. Thank You ANAESTHESIA FOR OPHTHALMIC SURGERY Anesthesia for ophthalmic surgery dramatically changed recently, much cataract surgery is now performed under topical anesthesia only and much other surgeries under local anesthetic nerve block. When general anesthesia is used the laryngeal mask airway has generally replaced endotracheal tubes. Intraocular pressure (IOP) Normal intraocular pressure is 10-20 mmHg. Increased IOP after some eye surgeries (particularly cataract) is typically due to retained ophthalmic viscosurgical device (the solution which used to maintaining the anterior chamber during surgical maneuvers) so, there are many factors that have to be taken into consideration that affect intraocular pressure. It may be lowered by: 1. Intravenous anesthetics (except ketamine). 2. Inhalational anesthetics. 3. Hypotension. 4. Hypocapnia. 5. Reduction in venous pressure, including head-up tilt. 6. Mannitol and acetazolamide. 7. Mechanical pressure on the eye to increase absorption of aqueous humor. It is may be raised by: Page 80 of 83 Anesthesia 2 – 3rd stage 1. Hypertension. 2. Hypercapnia. 3. Raised venous pressure, including head-down tilt. 4. Suxamethonium (transient effect). 5. Local anesthetic block. 6. Ketamine (has a little effect). The oculocardiac reflex: Traction on extraocular muscles, pressure on the eyeball, administration of a retrobulbar block, and trauma to the eye can elicit a wide variety of cardiac dysrhythmias ranging from bradycardia and ventricular ectopy to sinus arrest or ventricular fibrillation. This reflex consists of a trigeminal (V1) afferent and a vagal efferent pathway. The oculocardiac reflex is most commonly encountered in pediatric patients undergoing strabismus surgery, although it can be evoked in all age groups and during a variety of ocular procedures, including cataract extraction, enucleation, and retinal detachment repair. In awake patients, the oculocardiac reflex may be accompanied by nausea. Routine prophylaxis for the oculocardiac reflex is controversial. Anticholinergic medication is often helpful in preventing the reflex, and intravenous atropine or glycopyrrolate immediately prior to surgery is more effective than intramuscular premedication. Management of the oculocardiac reflex when it occurs includes: (1) Immediate notification of the surgeon and temporary cessation of surgical stimulation until heart rate increases (2) Confirmation of adequate ventilation, oxygenation, and depth of anesthesia (3) Administration of intravenous atropine (10 mcg/kg) if bradycardia persists (4) In resistant episodes, infiltration of the rectus muscles with local anesthetic. The reflex eventually fatigues (self-extinguishes) with repeated traction on the extraocular muscles. General anesthesia Indications for general anesthesia: Potential failure of cooperation by the patient, especially those with learning difficulties. Patient phobias, especially severe claustrophobia. Children. Long duration operation. Various technical surgical problems. Page 81 of 83 Anesthesia 2 – 3rd stage Premedication is not used routinely now for eye surgery, but a short-acting benzodiazepine may be given orally as premedication to anxious patients. Anticholinergic agents cause a dry mouth and discomfort and do not need to be given with premedication. They are more likely to be needed in strabismus or retinal surgery, but may be given intravenously after induction if necessary. Propofol used widely because of its short duration of action, pleasant induction and reduced post-operative nausea. Etomidate is useful in elderly or unhealthy patients because of its cardiac stability, reduction in IOP and rapid recovery. Moderate hyperventilation reduces PaCO2 and provides excellent operating conditions. Use of Rae tube is preferred in eye surgery Early on in the procedure, the surgeon should be encouraged to infiltrate a long acting local anesthetic by the sub-Tenon‟s route. This should successfully eliminate various requirements in anesthetic from the surgical stimulus and provide a stable anesthetic with a reduction in the amounts of general anesthetic agent required. Local anesthetic techniques 1. Topical: It is used for cataract surgery. 2. Sub-Tenon block: It is used for cataract surgery when immobile eye required. It is often unsatisfactory for vitreoretinal surgery. A blunt cannula is passed into the plane between Tenon‟s capsule and the sclera to inject the local anesthetic. It is often administrated by the surgeon without the help of the anesthetist. 3. Retrobulbar block: Injection of the local anesthetic into the muscle cone behind the eye. It is increasingly regarded as out of date and unsafe because the significant incidence of perforation of the globe, hemorrhage, and intradural injection. 4. Peribulbar block: It can be a true extradural injection, allowing the local anesthetic to diffuse into the muscle cone, or into the intraconal space. It is increasingly used vitreoretinal surgery and other forms where a greater level of akinesia and analgesia is needed ---------------------------------------------------------------------------------------------------------------- Page 82 of 83 Anesthesia 2 – 3rd stage References Morgan and Mikhail's Clinical Anesthesiology, _7th_Edition 2022 Smith and Aitkenhead’s Textbook of Anaesthesia Seventh Edition 2019 Miller’s Anesthesia, Ninth Edition 2020 Page 83 of 83