Regional Anesthesia (spinal, epidural, nerve block) Lab 1, University of Al Mashreq, 2020 PDF

University of Al mashreq College of medical sciences technologies Department of anesthesia and ICU 2nd semester Lab 1 REGIONAL ANAESTHESIA (SPINAL, EPIDURAL, NERVE BLOCK) BY ANAESTHESIA TECH. KH...

University of Al mashreq College of medical sciences technologies Department of anesthesia and ICU 2nd semester Lab 1 REGIONAL ANAESTHESIA (SPINAL, EPIDURAL, NERVE BLOCK) BY ANAESTHESIA TECH. KHALEL MOHAMMED ZAINAB A.MOHAMMED 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. Indications 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. contraindications : 1)Uncooperative or restless patients. 2) Some psychiatric patients. -preparation before local anesthetic is injected: 1) intravenous cannula. 2) a tilting table or trolley. 3) facilities of intermittent Ippv with oxygen. 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.  A- Central Neuraxial Blockade Spinal (intradural) anesthesia: Anatomy: The spinal cord usually ends at the level of L1 in adults and L3 in children. Indications - 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 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. Factors Effecting Distribution Cardiovascular Effects: Predominant action is venodilation Site of injection Reduces: Shape of spinal column Venous return Stroke volume Patient height Cardiac output Angulation of needle Blood pressure Volume of CSF Hypotension: Treatment Best way to treat is physiologic not pharmacologic Characteristics of local anesthetic Density ❖ Primary Treatment Increase the cardiac preload Large IV fluid bolus within 30 minutes prior to Specific gravity spinal placement, minimum 1 liter of crystalloid Dose ❖ Secondary Treatment Pharmacologic Volume Phenylephrine Patient position (during & after) Complications: Spinal headache: Immediate complications More common in women ages 13-40 Hypotension Treatment: Bradycardia and Cardiac arrest. High and Total spinal block leading to ✓ Bed rest (remain lying flat in bed as this relieves respiratory arrest. pain) Urinary retention. Epidural hematoma, Bleeding. ✓ Fluids (drink freely or IV fluid to maintain 2. Late complications hydration) Post dural puncture headache (PDPH) ✓ Simple analgesia such as paracetamol, Backache Nausea ✓ or aspirin or codeine may be helpful. Focal neurological deficit ✓ -Caffeine containing drink Bacterial meningitis Sixth Cranial nerve palsy ✓ -Blood patch Epidural (extradural) anesthesia: Epidural space : Potential space between the dura mater and ligament flavum Made up of vasculature, nerves, fat and lymphatic. 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 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. 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 6.Facial numbness Note: if beta blocked will only see increase in BP not HR 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  position of lumbar puncture Sitting position lateral or lying position  Comparison between spinal anesthesia and epidural anesthesia Spinal anesthesia Epidural anesthesia 1) Drug delivered to the subarachnoid space and 1) Drug delivered outside the dura (outside into the CSF CSF) 2) Injected only below the 3rd lumber vertebra to 2) May be given at cervical, thoracic, lumber or avoid piercing the spinal cord 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 block (muscle relaxation) 6) Gives profound block of all motor and sensory 6) Blocks a 'band' of nerve roots around the site of function below the level of injection 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 Contraindications to central neuraxial blockade: ❑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. 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.  B- Peripheral nerve blocks 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. 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).  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 began to embrace this technology, further demonstrating its utility and describing in detail the sonoanatomy of the brachial plexus.  Transversus Abdominis Plane (TAP) Block 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 use of TAP BLOCK Hernia repair Open appendicectomy Caesarian section Total abdominal hysterectomy Radical prostatectomy  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 o Age o body height and weight o 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) THANK YOU