Principles of Surgery (Preoperative care, Day case surgery, Anaesthesia & pain relief, and postoperative care & complications) PDF

Principles of Surgery (Preoperative care, Day case surgery, Anaesthesia & pain relief, and postoperative care & complications) Prepared by Dr Ibrahim Mousa Maaroof Higher Diploma student M.B.Ch.B. Dr Sarmad Nadhem Ismael Higher Diploma student M.B.Ch.B. Supervised by Assist. Prof. Dr Baderkhan Saee...

Principles of Surgery (Preoperative care, Day case surgery, Anaesthesia & pain relief, and postoperative care & complications) Prepared by Dr Ibrahim Mousa Maaroof Higher Diploma student M.B.Ch.B. Dr Sarmad Nadhem Ismael Higher Diploma student M.B.Ch.B. Supervised by Assist. Prof. Dr Baderkhan Saeed Ahmed Assist. Prof. Dr Azhy Muhammed Dewana 2 January 2024 1 PERIOPERATIVE CARE 2 January 2024 2 PREPERATIVE CARE 2 January 2024 3 PREOPERATIVE PLAN FOR THE BEST PATIENT OUTCOMES ● Gather and record all relevant information ● Optimise patient condition ● Choose surgery that offers minimal risk and maximum benefit ● Informed consent of the patient ● Anticipate and plan for adverse events ● Adequate hydration, nutrition and exercise are advised 2 January 2024 4 PATIENT ASSESSMENT • HISTORY TAKING • EXAMINATION • AIRWAY ASSESSMENT • INVESTIGATIONS 2 January 2024 5 HISTORY TAKING The history of past surgery and anaesthetic events can reveal the problems one may face during future procedures e.g. intraabdominal adhesions for planned laparoscopic surgery, a difficult airway or suxamethonium apnoea. The use of recreational drugs and alcohol consumption should be noted as they are known to be associated with adverse outcomes. A full drug history and list of allergies should be documented. Social history, ability to communicate and mobility are important in planning admission, discharge route and rehabilitation after surgery. 2 January 2024 6 KEY CONDITIONS IN PAST MEDICAL HISTORY Cardiovascular: Valvular heart disease, Ischaemic heart disease (angina, myocardial infarction, coronary stents), Hypertension, Heart failure, Dysrhythmia, Peripheral vascular disease, Cardiac devices, i.e. permanent pacemaker Respiratory: Chronic obstructive pulmonary disease, Asthma, Respiratory infections, Obstructive sleep apnoea symptoms Gastrointestinal: Peptic ulcer disease and gastro-oesophageal reflux, Liver disease Genitourinary tract: Urinary tract infection, Renal dysfunction, For females last menstrual period/pregnancy/breastfeeding status Neurological: Epilepsy, Cerebrovascular accidents and transient ischaemic attacks, Parkinson’s disease, Multiple sclerosis 2 January 2024 7 Psychiatric disorders: Cognitive function, Anxiety or depression Endocrine/metabolic: Diabetes, Thyroid dysfunction, Phaeochromocytoma, Porphyria Locomotor system: Osteoarthritis, Inflammatory arthropathy, i.e. rheumatoid arthritis, Disorders of muscle, i.e. muscular dystrophy, myasthenia, myopathy Haematological: Bleeding disorders, Personal or family history of deep vein thrombosis and pulmonary embolism, Objection to blood product transfusion, Haemoglobinopathy, i.e. sickle cell disease Infection: Human immunodeficiency virus/hepatitis/tuberculosis, Other, i.e. MRSA/COVID-19/drug-resistant organisms Previous surgery and anaesthesia: Problems encountered, i.e. Difficult Airway Society Alert, suxamethonium apnoea, Family history of problems with anaesthesia, i.e. malignant hyperpyrexia 2 January 2024 8 MEDICAL EXAMINATION General Anaemia, jaundice, cyanosis, frailty, nutritional status, sources of infection (teeth, feet, leg ulcers), height, weight and BMI Cardiovascular Pulse rate and rhythm, blood pressure, heart sounds, bruits, jugular venous pressure, peripheral oedema, exercise tolerance Respiratory Respiratory rate and effort, chest expansion and percussion note, breath sounds, oxygen saturation at rest and exertion, consider PEFR Gastrointestinal Abdominal masses, ascites, bowel sounds, hernia, genitalia Neurological Consciousness level, cognitive function, sensation, muscle power, tone and reflexes Airway assessment Mouth opening, neck extension, Mallampati score, thyromental distance, jaw protrusion, scarring to mouth or neck, dentition 2 January 2024 9 AIRWAY ASSESSMENT The difficulty encountered when performing airway manoeuvres, i.e. hand ventilation, intubation and front of neck access, can be predicted to some extent by simple examination. Failure to assess and plan airway management can have fatal consequences. 2 January 2024 10 The patient is assessed for: o modifed Mallampati class; o mouth opening >3 cm; o thyromental distance >6.5 cm; o thyrosternal distance >12.5 cm; o ability to protrude the jaw; o ability to extend the head at the atlantooccipital junction When more than one of the above tests are abnormal, the chances of experiencing difficulty in obtaining and securing the airway become greater. Poor dentition, facial hair, upper airway tumours/scarring/infections, obesity and neck size are also important factors that will affect the airway management plan. Previous anaesthetic charts or alerts carried by patients for a difficult airway are invaluable sources when assessing a patient. 2 January 2024 11 AIRWAY ASSESSMENT (MALLAMPATI TEST AS MODIFED BY SAMSOON AND YOUNG). Grade 1: Fauces, pillars, soft palate and uvula seen Grade 2: Fauces, soft palate with some part of uvula seen Grade 3: Soft palate seen Grade 4: Hard palate only seen 2 January 2024 12 INVESTIGATIONS Guidelines produced by the UK’s National Institute for Health and Care Excellence (NICE) set out the investigations needed for various categories of elective surgery and American Society of Anesthesiologists (ASA) score of the patient. The following are some of the tests done preoperatively, although not all are done routinely or are recommended by NICE. 2 January 2024 13 • Full blood count (FBC). is needed for: o Major operations o Elderly o In those with anaemia or pathology with ongoing blood loss and chronic disease. • Haemoglobin A1c (HbA1c) level. This should be measured in patients with diabetes who have not had it measured in the last 3 months. • Sickle cell test. Not routinely offered, but in cases of suspicion of a sickle crisis or a family history of sickle cell disease a sickle cell test is needed. • Urea and electrolytes (U&Es). are needed o o o o o Before all major operations, In patients over 65 years of age In patients with cardiovascular, renal or endocrine disease If significant blood loss is anticipated. In those on medications that affect electrolyte levels, e.g. steroids, diuretics, digoxin, nonsteroidal anti-inflammatory drugs, intravenous fuid or nutrition therapy 2 January 2024 14 • Liver function tests. indicated in o o o o o o Patients with jaundice, Known or suspected hepatitis, Cirrhosis Malignancy Alcohol excess or Poor nutritional status • Clotting/coagulation screen. needed if a patient has • A history suggestive of a bleeding diathesis • Liver disease • Eclampsia • Cholestasis or • Is on antithrombotic or anticoagulant agents or • Has a family history of a bleeding disorder. It should be noted that the effects of antiplatelet agents, lowmolecularweight heparins (LMWHs) and newer agents affecting factor Xa cannot be measured by routine laboratory tests. 2 January 2024 15 Electrocardiogram (ECG). This is required for o patients over 65 years of age or o symptomatic patients with a history of rheumatic fever, diabetes or cardiovascular, renal or cerebrovascular disease, with or without severe respiratory problems. Chest radiograph. Not routinely offered unless there is concern on clinical examination. Echocardiogram (echo). Consider in those with heart murmurs who are o symptomatic or o in those with signs of heart failure. 2 January 2024 16 Urine tests. Only consider microscopy and culture of midstream urine if infection would influence the decision to operate. β-Human chorionic gonadotrophin (pregnancy test). Women of childbearing age should be asked sensitively about their pregnancy status as this will affect the surgical plan and consent. Pregnant patients must be consented for the risk to a fetus that surgery and anaesthetic pose, and obstetric advice sought. In addition, on the day of surgery the woman should be consented for a urine/ serum pregnancy test. 2 January 2024 17 OTHERS: • Venous bicarbonate. For patients who have screened as being at high risk for obstructive sleep apnoea (OSA). Followed by formal sleep studies if significant OSA is a concern. • Arterial blood gases. A low-cost tool that can give quick and vital information in acute or chronic severe respiratory conditions, acid– base disturbances and conditions where there is a changing milieu, e.g. immediately before kidney transplant. • Blood group and cross-match if expected blood loss >500 mL. 2 January 2024 18 • Methicillin-resistant Staphylococcus aureus (MRSA) swabs. • Coronavirus 2019 (COVID-19) polymerase chain reaction (PCR) swabs. • Spirometry. • Cardiopulmonary exercise testing to assess ftness for highrisk surgery. • Specialist radiological views are sometimes required. If imaging is going to be needed during surgery, this needs to be planned in advance. 2 January 2024 19 COMMON PREOPERATIVE PROBLEMS AND MANAGEMENT CARDIOVASCULAR DISEASE Patients who can climb a flight of stairs without getting short of breath, having chest pain or needing to stop are likely to tolerate a wide range of surgeries with an acceptable risk of perioperative cardiovascular morbidity and mortality. Patients at high risk are those with (IHD), CHF, arrhythmias, severe PVD, VCD or significant renal impairment, especially if they are undergoing major intraabdominal or intrathoracic surgery. 2 January 2024 20 ISCHAEMIC HEART DISEASE Patients established on βblockers and statins should have their medication continued perioperatively. Most long-term cardiac medications should be continued over the perioperative period. (ACEi) and ARBs are often omitted 24 hours prior to surgery to prevent intraoperative hypotension, and restarted the next day for most surgery. In patients with IHD the cardiac and coronary reserve can be evaluated using a stress test (stress ECG, stress echo, myocardial scintigraphy). After a proven myocardial infarction (MI), elective surgery should be postponed for 3–6 months. 2 January 2024 21 HYPERTENSION Prior to elective surgery blood pressure should be controlled to <160/100 mmHg. If a new antihypertensive agent is introduced, a stabilisation period of at least 2 weeks should be allowed. 2 January 2024 22 HEART FAILURE Those with ejection fractions of less than 35%, and in whom the failure is undiagnosed or its severity underestimated, are at highest risk. The patient’s functional capacity needs to be assessed and surgery may have to be delayed for investigations such as an echo and/or for optimisation of medical therapy. B-type natriuretic peptide is a useful marker and can be prognostic. β-blockers and probably ACE inhibitors should be continued. A LV EJ of <35% should be discussed with a cardiologist and optimised. 2 January 2024 23 DRUG-ELUTING CORONARY STENTS (DES) PCI is the treatment of choice for ACSs, and many patients receive stents and are on dual antiplatelet therapy for 12 months. If surgery is absolutely necessary within the period of dual antiplatelet therapy, the management strategy should be decided jointly by the surgeon, cardiologist, anaesthetist and patient, as it is essential to consider the balance of risk of continuing antiplatelet agents (with the risk of increased bleeding) and stopping them (with the risk of stent thrombosis). 2 January 2024 24 DYSRHYTHMIAS In patients with (AF), β-blockers, digoxin or CCBs should be continued in order to control rate. New AF or atrial flutter should be investigated and treated. These patients should be considered for cardioversion as restoring sinus rhythm can improve cardiac output by 15% . Patients with an abnormal rhythm on ECG, for example tachycardia/bradycardia or heart block, should also be discussed with a cardiologist . 2 January 2024 25 Symptomatic heart blocks and asymptomatic second (Mobitz II) and third degree heart blocks, if discovered at the preoperative assessment clinic, will need cardiology consultation and potentially temporary or permanent pacemaker insertion. Warfarin in patients with AF should be stopped 5 days preoperatively to achieve an international normalised ratio (INR) of 1.5 or less, which is safe for most surgery. 2 January 2024 26 The newer anticoagulants such as dabigatran (direct thrombin inhibitor) or rivaroxaban, apixaban and edoxaban (direct factor Xa inhibitors) do not have antagonists and must be stopped preoperatively, generally for 2–3 days in patients with normal renal function and longer when renal function is impaired. Alternative anticoagulation is not required in the perioperative period unless the risk of stroke is high (assessed using the CHA2DS2VASc [congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke or transient ischemic attack, vascular disease, age 65–74 years, sex category] score). Decisions on bridging therapy should balance the risks of stroke and bleeding. 2 January 2024 27 IMPLANTED PACEMAKERS AND CARDIAC DEFBRILLATORS Checks and appropriate reprogramming should be done preoperatively by specialists and advice followed. Monopolar diathermy activity during surgery may be sensed by the pacemaker as ventricular fibrillation or a paced beat. Therefore, cardioversion and overpace modes must be turned of (and switched back on after surgery) or converted to ‘ventricle paced, not sensed with no response to sensing’ (VOO) mode. Bipolar diathermy should be made available at surgery. 2 January 2024 28 VALVULAR HEART DISEASE An echo is required in symptomatic patients with a new murmur. Patients with prosthetic valves are normally monitored with surveillance echo at intervals. In patients with mechanical heart valves, warfarin needs to be stopped preoperatively and bridging anticoagulation given to prevent valve thrombosis. Bridging options include unfractionated heparin infusions or LMWHs and should be done under guidance agreed with haematology. Bridging therapy should continue postoperatively until the patient is reestablished on warfarin with a therapeutic INR but must be balanced with the postoperative bleeding risk. 2 January 2024 29 CEREBRAL VASCULAR DISEASE • Patients who have suffered a CVA have been shown to have a higher rate of major adverse cardiovascular event (MACE) postoperatively. • This is highest in the first 3 months after a stroke. • The urgency of surgery needs to be discussed with the surgeon, anaesthetist and a stroke physician. • Ideally elective surgery is postponed until MACE risks stabilise after 9 months. • The bleeding versus thrombosis risk of continuing dual antiplatelet therapy needs to be considered. 2 January 2024 30 RESPIRATORY DISEASE Patients with severe disease are at risk of pneumonia and respiratory failure in the postoperative period. Severe disease would include patients with a forced expiratory volume in the first second (FEV1) of less than 30% of predicted value, dependence on oral steroid treatment, home ventilation or oxygen therapy or a PaCO2 level of greater than 6 kPa. Patients should continue to use their regular inhalers until the start of anaesthesia. Brittle asthmatics may also need extra steroid cover. 2 January 2024 31 Encourage the patients to be compliant with the medications and stop smoking. Stopping smoking reduces carbon monoxide levels and offers the patient a better ability to clear sputum. Evidence suggests that preoperative inspiratory muscle training significantly improves respiratory (muscle) function in the early postoperative period, reducing the risk of pulmonary complications. Regional anaesthetic techniques and less invasive surgical options should be considered in severe cases. Elective surgery should be postponed until acute exacerbations are treated. 2 January 2024 32 The patient should be referred to a respiratory physician if: ● there is a severe disease or significant deterioration; ● major surgery is planned in a patient with significant respiratory comorbidities; ● right heart failure is present – dyspnoea, fatigue, tricuspid regurgitation, hepatomegaly and oedematous feet; ● the patient is young and has severe respiratory problems (may indicate a rare condition). 2 January 2024 33 GASTROINTESTINAL DISEASE Regurgitation risk Patients undergoing general anaesthesia or sedation have a risk of regurgitation of stomach contents and aspiration pneumonia. To reduce this risk patients should fast preoperatively. This should be clearly explained to the patient: 6 hours for solids or nonclear fluids (e.g. milk), 2 hours for clear fluids and 4 hours for infants consuming breast milk. 2 January 2024 34 Patients with hiatus hernia, obesity, pregnancy or diabetes are at higher risk of pulmonary aspiration, even if they have been fasted appropriately before elective surgery. Clear antacids, H2receptor blockers, e.g. ranitidine, or proton pump inhibitors, e.g. omeprazole, may be given at an appropriate time in the preoperative period to reduce stomach acidity. Liver disease In patients with liver disease, the cause of the disease needs to be known, as well as any evidence of clotting problems, renal involvement and encephalopathy. 2 January 2024 35 Elective surgery should be postponed until any acute episode has settled, e.g. cholangitis. The presence of ascites, oesophageal varices, hypoalbuminaemia or sodium and water retention should be noted, as all can influence the choice and outcome of anaesthesia and surgery. Patients with cirrhosis undergoing major surgery have a very high mortality; the Model for End stage Liver Disease (MELD) can be used to predict mortality of cirrhotic patients undergoing non-transplant surgery. If alcohol addiction is the aetiology then reduction of alcohol intake should be encouraged but abstinence must be medically supervised to prevent delirium tremens. 2 January 2024 36 Jaundice Patients with obstructive jaundice are at risk of developing renal failure post-operatively (hepatorenal syndrome). This is thought to be due to the nephrotoxic effect of toxins normally eliminated by the liver, as well as circulatory changes. • Ensure adequate hydration. When the patient is NBM, prescribe IV normal saline 1L over 6– 8h. • Insert a urinary catheter and start an hourly fluid balance chart. • Measure U&E and liver function tests (LFTs) daily. • Coagulopathy in long- standing cholestatic jaundice may be improved with vitamin K 1mg IV— discuss with haematology. • Avoid or reduce the doses of hepatotoxic drugs and drugs with hepatic elimination. 2 January 2024 37 GENITOURINARY DISEASE Renal failure Underlying conditions leading to chronic renal failure such as diabetes mellitus, hypertension and IHD should be stabilised before elective surgery. Appropriate measures should be taken to treat acidosis, hypocalcaemia and hyperkalaemia of greater than 6 mmol/L. Arrangements should be made to continue peritoneal dialysis or haemodialysis until a few hours before surgery. After the final dialysis before surgery, a blood sample should be sent for FBC and U&Es. Patients with chronic renal failure often have chronic anaemia that is well tolerated; therefore, preoperative blood transfusion is often not necessary. Optimisation of the haemoglobin is best guided by the renal team. 2 January 2024 38 Urinary tract infection Uncomplicated urinary tract infections are common in women, while outflow uropathy with chronically infected urine is common in men. These infections should be treated before embarking on elective surgery where infection carries dire consequences, e.g. joint replacement. For emergency procedures, antibiotics should be started and care taken to ensure that the patient maintains a good urine output before, during and after surgery. 2 January 2024 39 ENDOCRINE AND METABOLIC DISORDERS Malnutrition A BMI of less than 18.5 indicates nutritional impairment and a BMI below 15 is associated with significant hospital mortality. Nutritional support for a minimum of 2 weeks before surgery is required to have any impact on subsequent morbidity. If a patient is unlikely to be able to eat for a significant period postoperatively this can be anticipated and alternative nutritional support must be planned. 2 January 2024 40 Obesity Morbid obesity can be defined as BMI of more than 35 (other definitions exist) and is associated with an increased risk of postoperative complications. If possible, surgery should be delayed until the patient is more active and has lost weight. If this fails, prophylactic measures need to be taken, such as preventative measures for acid aspiration and deep vein thrombosis (DVT). OSA that is unrecognised has been shown to be associated with a higher incidence of MACE in comorbid patient groups. 2 January 2024 41 Identification of those at higher risk by using a clinical scoring system, such as the perioperative sleep apnoea prediction (PSAP) score, can rationalise referral for formal sleep apnoea studies. Urgency of surgery may preclude full investigation and treatment preoperatively. Patients with severe OSA require 6 weeks of nocturnal continuous positive airway pressure (CPAP) use preoperatively to reduce their risks. Associated risks need to be explained prior to the surgery and an appropriate anaesthetic technique planned with postoperative monitoring. 2 January 2024 42 Diabetes mellitus Diabetes and associated cardiovascular and renal complications should be controlled to as near a normal level as possible before embarking on elective surgery. For elective surgery, an HbA1c of <8.5% is recommended. Lipid-lowering medication should be started in patients who are in a high-risk group for cardiovascular complications of diabetes. Patients with diabetes should be first on the operating list and their antidiabetic medication adjusted as per local or national guidance, as they will miss a meal preoperatively. 2 January 2024 43 Minor surgery • Oral- controlled— give normal regimen. • Insulin- controlled— omit preoperative insulin on day of surgery; monitor BS every 4h; restart normal insulin once oral diet is established. Major surgery • Oral- controlled— omit long- acting hypoglycaemics preoperatively. Monitor BS every 4h. If BS exceeds 15mmol/ L, start IV insulin regimen. • Insulin- controlled— commence on IV insulin sliding scale preoperatively once NBM and continue until normal diet is re-established. Check BS every 4h. Restart normal insulin regimen (initially at half dose) once oral diet is established. 2 January 2024 44 Emergency surgery • Check for existing ketoacidosis. If present, use medical treatment algorithm to control BS and postpone surgery until BS <20mmol/ L unless the condition is life- threatening. • Use IV insulin sliding scale for all patients to optimize BS control. A typical IV sliding scale (soluble insulin with 5% glucose) is: • BS <4mmol/ L: infusion 0.5U/ h + consider medical review. • BS 4– 15mmol/ L: infusion 2.0U/ h. • BS 15– 20mmol/ L: infusion 4.0U/ h. • BS >20mmol/ L: infusion 4.0U/ h + consult diabetology team and consider treatment as for ketoacidosis. 2 January 2024 45 Adrenocortical suppression Patients receiving oral adrenocortical steroids should be asked about the dose and duration of the medication to determine the need for supplementation with extra doses of steroids perioperatively so as to avoid an Addisonian crisis. A patient taking >5 mg prednisolone equivalent within a month of surgery will require supplementation at induction and postoperatively. Neuroendocrine tumours, including phaeochromocytoma, carcinoid, gastrinoma, VIPomas and insulinoma, have specific treatments that must be started preoperatively in liaison with specialist endocrinology physicians. 2 January 2024 46 HAEMATOLOGICAL DISORDERS Anaemia and blood transfusion Patients found to be newly anaemic (haemoglobin <130 g/L), with an expected operative blood loss of >500 mL, should be investigated for the cause of their anaemia. Any vitamin or iron deficiency should be corrected before proceeding for elective surgery. Chronic anaemia is well tolerated in the perioperative period where <500 mL blood loss is expected, but where possible should be corrected. Preoperative transfusion may be considered rarely for elective patients when guided by a haematologist. Local policy should agree which procedures require a preoperative ‘group and save’ or cross-matched blood sample. 2 January 2024 47 Some patients may refuse blood transfusion, for example a Jehovah’s Witness. In such a case, during the consent process discussion should include which blood product and/or device system (e.g. cell salvage, reinfusion from drains) is acceptable. The discussion should extend to other areas, for example whether refusal of transfusion would apply in life-threatening situations. As in all consent processes, the discussion and outcome should be clearly documented. Thrombophilia Factor V Leiden and deficiencies in antithrombin III and proteins C and S increase the patient’s thrombosis risk. The patient will need special discussion with a haematologist to tailor their venous thromboembolism prophylaxis. For all other patients a DVT risk assessment should be made preoperatively and precautions planned as per local or national guidance. 2 January 2024 48 RISK FACTORS FOR THROMBOSIS Age >60 years Obesity (BMI >30 kg/m2) Trauma or surgery (especially of the abdomen, pelvis and lower limbs) Total anaesthesia time >90 minutes Reduced mobility for more than 3 days Pregnancy/puerperium Varicose veins with phlebitis Drugs, e.g. oestrogen contraceptive, HRT, smoking Known active cancer or on treatment, signifcant medical comorbidities, critical care admission Family/personal history of thrombosis, e.g. defciencies in antithrombin III, protein S or C 2 January 2024 49 • The progesterone-only contraceptive pill should be continued; • however, the risks of continuing the combined pill (slight increased risk of significant thrombosis) should be weighed against the risks of an unplanned pregnancy. • Consider stopping oestrogen-containing oral contraceptives or hormone replacement therapy 4 weeks before surgery (NICE guidance). Bleeding disorders Bleeding disorders such as haemophilia, von Willebrand disease or thrombocytopenia are best discussed with haematology preoperatively. 2 January 2024 50 NEUROLOGICAL AND PSYCHIATRIC DISORDERS Anticonvulsants and anti-Parkinson’s medication must be continued perioperatively to help early mobilisation of the patient, and patients should be planned early on a theatre list to reduce starvation times. Parenteral medication plans can be set in place preoperatively if there is potential for a prolonged ‘nil by mouth’ period postoperatively. 2 January 2024 51 Lithium should be stopped 24 hours prior to major surgery but can be continued for minor surgery with careful fluid management and U&Es monitoring. The anaesthetist should be informed if patients are on psychiatric medications, such as tricyclic antidepressants or monoamine oxidase inhibitors (MAOIs), as these may interact with anaesthetic drugs. Case by case decisions with a psychiatrist must be undertaken as stopping irreversible MAOIs safely may take many weeks of planning under psychiatric supervision. 2 January 2024 52 Musculoskeletal disorders • Muscular disorders have serious implications and require a tailored anaesthetic approach. They include muscular dystrophies, myotonic dystrophy and myasthenia gravis and a personal or family history of malignant hyperpyrexia. • Rheumatoid arthritis can lead to an unstable cervical spine with the possibility of spinal cord injury during intubation. Therefore, flexion and extension lateral cervical spine radiographs should be obtained in symptomatic patients. • Assessment of the severity of renal, cardiac, valvular and pericardial involvement as well as restrictive lung disease should be carried out. 2 January 2024 53 • Rheumatologists will advise on steroids and disease-modifying drugs so as to balance immunosuppression (chance of infections) against the need to stabilise the disease perioperatively (stopping diseasemodifying drugs can lead to flare up of the disease). • In patients with ankylosing spondylitis, in addition to the problems discussed above, techniques of spinal or epidural anaesthesia are often challenging. • Patients with systemic lupus erythematosus may exhibit a hypercoagulable state along with airway difficulties. 2 January 2024 54 PHYSICAL FITNESS Functional physical fitness can be judged by the ability to tolerate metabolic equivalent tasks (METs). Metabolic equivalent tasks (METs): • • • • • 1 MET = 3.5 mL O2/kg/min (oxygen consumption by a 40-yearold, 70-kg man at rest) 1 MET = eating and dressing 4 METs = climbing two flights of stairs 6 METs = short run >10 METs = able to participate in strenuous sport One MET is equivalent to the oxygen consumption of an adult at rest (~3.5 mL/kg/min). If the patient is able to perform >4 METs (e.g. climbing at least one flight of stairs) they are accepted to proceed for low-risk surgery in the USA and Europe. 2 January 2024 55 However this depends on a subjective assessment of the ability of a patient and may be overestimated by them. The Duke Activity Status Index (DASI) is a less subjective patient questionnaire. An estimate of the patient’s peak oxygen consumption (VO2 peak) can be calculated from their point score. Although it correlates with cardiopulmonary exercise testing (CPET), some patients who score poorly on DASI go on to score well on CPET. An objective measure of fitness is required for high-risk surgery. 2 January 2024 56 CARDIOPULMONARY EXERCISE TESTING CPET is the gold standard measurement of a patient’s fitness. The oxygen consumption (VO2) and carbon dioxide production (VCO2) of the patient are measured while they undergo a 10minute period of incrementally demanding exercise (usually on a cycle ergometer) up to their maximally tolerated level. CPET is based on the principle that, when a subject’s delivery of O2 to active tissues becomes inadequate, anaerobic metabolism begins; lactate is buffered by bicarbonate and the resulting CO2 increases out of proportion to the escalation in physical difficulty and O2 consumption. The ‘anaerobic threshold’ (AT) is the VO2 in mL/kg/min at which this occurs. Peak oxygen consumption is also measured. This is the end product of a subject’s combined respiratory, cardiac, vascular and musculoskeletal fitness, and subjects with either an AT below 11 mL/kg/min or a VO2 peak below 15 mL/kg/min are at higher risk of morbidity and mortality after major surgery. 2 January 2024 57 Patients who are found to be unfit can be enrolled in prehabilitation. This involves supervised exercise over 4–6 weeks with the aim of improving the patient’s AT and reducing their risk profile. Where CPET is not available, the low-cost incremental shuttle walk test (ISWT) is an attractive option. It depends on the patient’s ability to walk at increasing speed over a fat surface. Patients who fail to achieve 350 metres on the ISWT have been shown to be at higher risk for oesophageal surgery. It correlates well with VO2 peak but does not identify all low risk patients as it is subject to patient motivation and is affected by sex, age and height. 2 January 2024 58 ASSESSMENT OF RISK FACTORS CONTRIBUTING TO RISK PATIENT FACTORS THAT PREDISPOSE TO HIGH RISK OF MORBIDITY AND MORTALITY: ● Previous severe cardiorespiratory illness, e.g. acute myocardial infarction, COPD or stroke ● Late-stage vascular disease involving the aorta ● Age >70 years with limited physiological reserve in one or more vital organs ● Extensive surgery for carcinoma ● Acute abdominal catastrophe with haemodynamic instability (e.g. peritonitis) ● Acute massive blood loss >8 units ● Septicaemia ● Positive blood culture or septic focus ● Respiratory failure: PaO2 <8 kPa or FiO2 >0.4 or mechanical ventilation >48 hours ● Acute renal failure: urea >20 mmol or creatinine >260 mmol/L 2 January 2024 59 S U R G E R Y- S P E C I F C E S T I M AT E S O F R I S K 2 January 2024 60 RISK PREDICTION  The Royal College of Surgeons of England has recommended that patients who are predicted to have >5% mortality risk should have active consultant input in all stages of their management.  Surgical procedures in those with predicted mortality of >10% should be conducted under the direct supervision of a consultant surgeon or anaesthetist, unless the consultants are satisfed with the seniority and competence of the staf managing these patients.  Moreover, those with a mortality >10% should be managed in the critical care facility postoperatively. 2 January 2024 61 A number of scoring systems have been developed over the years with the aim of identifying high-risk patients American Society of Anesthesiologists system The POSSUM score Lee’s Revised Cardiac Risk index ACS NSQIP score 2 January 2024 62 American Society of Anesthesiologists system OPERATIVE MORTALITY BY AMERICAN SOCIETY OF ANESTHESIOLOGISTS (ASA) GRADE ASA grade Description 30-day mortality (%) I Healthy 0.1 II Mild systemic disease, no functional limitation 0.7 III Severe systemic disease, definite functional limitation 3.5 IV Severe systemic disease, constant threat to life 18.3 V Moribund patient unlikely to survive 24 hours with or without operation 93.3 E Emergency operation – 2 January 2024 63 • The POSSUM score • The POSSUM (Physiologic and Operative Severity Score for the enUmeration of Mortality and Morbidity) and its modifications (PPOSSUM, CRPOSSUM) are used to predict all cause mortality in postoperative critical care patients as well as non-cardiac morbidity. 2 January 2024 64 Lee’s Revised Cardiac Risk index • Lee’s Revised Cardiac Risk index (RCRI) uses objective indices based on weighted scores pertaining to surgery and comorbidity. This stratifes cardiac risk but is not designed to predict mortality THE REVISED CARDIAC RISK INDEX OF LEE Risk factors Risk of major cardiac complications (%) History of ischaemic heart disease History of compensated or prior heart failure History of cerebrovascular disease Diabetes mellitus Renal insufficiency (creatinine >177 μmol/L  2mg/dL) High-risk surgery Number of factors 0 = 0.4 1 = 0.9 2 = 7.0 3+ = 11.0 2 January 2024 65 ACS NSQIP score • The American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) surgical risk score estimates the chance of a complication or death after surgery for more than a thousand different surgical procedures. It compares the patient’s risk with an average person’s risk. • It is a Web-based tool done preoperatively. The risk is calculated based on surgical procedure and 19 patient-specific preoperative risk factors. 2 January 2024 66 PREOPERATIVE ASSESSMENT FOR EMERGENCY SURGERY • Same as in elective surgery, • Except the urgency of surgery should be graded, e.g. by using the NCEPOD classification of intervention, and emergency theatre cases should be prioritised accordingly, i.e. • immediate (within minutes), • urgent (within hours), • expedited (within days) or • elective (timing to suit patient, hospital and staff). • Optimisation before urgent surgery can be more effective in a critical care environment and patients may need to be admitted to critical care preoperatively. 2 January 2024 67 DAY CASE SURGERY 2 January 2024 68 INTRODUCTION The definition of day case surgery is the planned day admission of a patient to hospital for a surgical procedure, after which there is subsequent successful and safe discharge back home on the same day. This has significant implications, including reducing hospital stay, hospital- acquired infection, and health care- related costs, whilst also improving patient experience and service efficiency. 2 January 2024 69 PATIENT SELECTION CRITERIA Surgical Traditionally day surgery was limited to cases that lasted less than 1 hour but surgical procedures lasting 3–4 hours are now being routinely performed as successful day cases. Day surgery surgical criteria include the following: 1. There must be a low risk of significant immediate postoperative complications, e.g. catastrophic bleeding or airway compromise. 2. The patient should be able to eat and drink or take oral nutrition postoperatively. 3. Postoperative pain needs to be managed by oral painkillers, which may be in conjunction with local anaesthetic infiltration or peripheral nerve block. 4. The patient should be able to mobilise postoperatively with or without aid. 2 January 2024 70 Medical • There should be no arbitrary cut-offs according to age, weight or criteria specified by the American Society of Anesthesiologists. A patient’s suitability for day surgery should be judged on their comorbidities and functional status. • Older patients and patients with higher body mass index (BMI) benefit from awake surgery or short-acting anaesthetic agents with a good recovery profile. Medical exclusions to day surgery: ● Unstable ASA 3 ● ASA 4 or 5 ● Any poorly controlled abnormality/comorbidity 2 January 2024 71 Diabetes • UK national guidance recommends that patients with well-controlled diabetes (haemoglobin A1c [HbA1c] <8.5%) can be safely managed as a day case. • Poorly controlled surgery delayed until their diabetes is well controlled. • If surgery cannot wait or it is thought the underlying disorder (e.g. tooth infection) is causing the diabetes control to be disrupted then diabetic control should be optimised as much as possible prior to surgery. Epilepsy • well-controlled  proceede • Poorly controlled  be optimised prior to any elective surgery. 2 January 2024 72 • Obesity • Guidance from the Association of Anaesthetists of Great Britain and Ireland/BADS in 2019 states that ‘even morbidly obese patients can be safely managed in expert hands, with appropriate resources’. • Preoperative assessment of patients should routinely include STOPBANG (Snoring, Tiredness, Observed apnoeas, Pressure [hypertension], Body mass index, Age, Neck circumference, Gender) to identify undiagnosed OSA (obstructive sleep apnoea). 2 January 2024 73 • The Society for Obesity and Bariatric Anaesthesia (SOBA) Guideline for Anaesthesia of the obese patient identifies a number of risk factors that may make day surgery unsuitable, e.g. poor functional capacity, oxygen saturation <94% on air, STOP-BANG ≥5. • Obese patients considered suitable for day surgery should receive a short-acting anaesthetic, avoiding long-acting opiates, with allowance for the additional time that may be required anaesthetically, surgically and for recovery. 2 January 2024 74 2 January 2024 75 Social Social criteria for day surgery include: 1. Adequate housing conditions such as heating, an inside toilet and access to a phone. 2. The patient should live within a 1-hour drive of a hospital. 3. A responsible adult should be able to stay with the patient for 24 hours after a regional anaesthetic/general anaesthetic. 2 January 2024 76 ADMISSION AND LIST PLANNING • Day surgery patients should follow the same starvation guidance as any other elective patient. • All patients, but especially day surgery patients, should be encouraged to walk to theatre. • Consider the list order to optimise successful day surgery and therefore put operations with longer recovery times or patients who take longer to recover early on the lists. • This needs to be balanced with patients who would benefit from being first on the list, such as patients with insulin-dependent diabetes and patients with learning difficulties who would struggle to wait for long periods of time. 2 January 2024 77 LIST PLANNING Operation with potentially might longer recovery times Types of patients who need longer recovery time Tonsillectomy Knee replacement Very elderly High BMI Hip replacement Complex laparoscopic cholecystectomy 2 January 2024 78 DISCHARGE • In general, there should be no time restriction except for certain procedures, e.g. patients should remain in hospital until 6 hours after tonsillectomy. • Take-home medications should provide adequate pain relief and may include an antiemetic. • These should be prescribed when the patient is in theatre and prepacks of common analgesics should be used to improve the efficiency of prescribing and reduce delays to discharge. 2 January 2024 79 DISCHARGE CRITERIA ● Vital signs stable for at least 1 hour ● Correct orientation as to time, place and person if appropriate ● Adequate pain control with supply of oral analgesia ● Understands how to use oral analgesia supplied ● Ability to dress and walk where appropriate ● Minimal nausea, vomiting or dizziness ● Has taken oral fluids ● Minimal bleeding or wound drainage ● Has passed urine (if appropriate) ● Has a responsible adult to take them home ● Written and verbal instructions given about postoperative care ● Knows when to come back for follow-up (if appropriate) ● Emergency contact number supplied 2 January 2024 80 Anaesthesia and pain relief Ground rules for anaesthesia ● Safe surgery is achieved by close teamwork between the surgeon and the anaesthetist ● Safety checklists ensure that things are not forgotten ● Risk assessments allow the best strategy to be chosen ● Anaesthetists are extending their care into the pre- and postoperative phases PREPARATION FOR ANAESTHESIA Enhanced recovery programs A careful preassessment, multidisciplinary approach and standardized care pathway with a carefully chosen anaesthetic and analgesic technique. GENERAL ANAESTHESIA Amnesia: loss of awareness Analgesia: pain relief Muscle relaxation • Induction of general anaesthesia is most frequently done by intravenous agents. Propofol is the most widely used induction agent and can be used for maintenance of anaesthesia, etomidate and ketamine less. • Inhalational induction using agents such as non-pungent sevoflurane is useful in children Airway during anaesthesia • Loss of muscle tone as a result of general anaesthesia means that the patient can no longer keep their airway open They will also be unable to breathe. • A laryngeal mask airway or endotracheal tube is then inserted, and the patient is allowed to breathe. Fiberoptic video assisted bronchoscope Muscle relaxation • Pharmacological blockade of neuromuscular transmission by neuromuscular blocking agents provides relaxation of muscles, allowing easy surgical access • Neuromuscular blocking agents are broadly classified into depolarising and non-depolarizing groups . • Suxamethonium is the most commonly used depolarizing agent. • Non-depolarising muscle relaxants act by competitive blockade of postsynaptic receptor, Eg: neostigmine. Ventilation during anaesthesia Intermittent positive-pressure ventilation • Volume controlled, which ensures adequate gas entry but risks high-pressure damage • Pressure controlled, which avoids high-pressure damage but risks inadequate ventilation • PEEP reduces alveolar collapse and reduces vascular shunting so improving perfusion. Monitoring and care during anaesthesia A minimum basic monitoring of cardiovascular parameters is required during surgery. Vascular • electrocardiogram (ECG); • blood pressure; Adequacy of ventilation • inspired oxygen concentration; • oxygen saturation by pulse oximetry; • end-tidal carbon dioxide concentration LOCAL ANAESTHESIA • Local anaesthetic drugs may be used to provide anaesthesia and analgesia • Local anaesthetic agents such as lignocaine and bupivacaine exert their effect by causing a local, reversible blockade of nerve conduction by reducing nerve membrane sodium permeability • Available techniques include topical anaesthesia, local infiltration, regional nerve blocks and central neuraxial blocks Signs of local anaesthetic toxicity Early • Numbness/tingling of the tongue • Perioral tingling • Anxiety • Lightheadedness • Tinnitus Late • Loss of consciousness • Convulsions • Cardiovascular collapse • Apnea Intravenous regional anaesthesia (Bier’s block) • Bier’s block produces excellent anaesthesia for short surgery, particularly for the upper limb • The proximal cuff of the double tourniquet is inflated, followed by intravenous injection of prilocaine into the cannula. • After 20 minutes the distal cuff of the tourniquet is inflated and then the proximal cuff is deflated. Spinal anaesthesia • Is the introduction of local anaesthetic, usually lidocaine or bupivacaine, into the subarachnoid space • To protect against damage to the spinal cord, spinal anaesthesia is administered below L2, either at the L3/4 or L4/5 level. • Injection of 2–4 mL of local anaesthetic produces a dense block up to T6 level and giving 2–3 hours of surgical Anaesthesia Spinal anaesthesia • Is used extensively for lower limb, obstetric and pelvic surgery. • The addition of opioids provides prolonged postoperative analgesia • Aspiration of subarachnoid fluid confirms the correct site of the spinal block needle Epidural anaesthesia • Epidural anaesthesia involves the injection of local anaesthetic into the epidural space, which extends along the entire vertebral canal between the ligamentum flavum and dura mater • Epidural anaesthesia is slower in onset than spinal but has the advantage of prolonged analgesia • Larger volume (10–20 mL) of local anaesthetic is required to achieve anaesthesia Epidural anaesthesia • Continuous infusion of weak local anaesthetic combined with opioids is routinely used for postoperative analgesia • Epidural anaesthesia is technically more difficult than spinal anaesthesia Complications of epidural anasthesia Postoperative analgesia • Good postoperative analgesia is essential in ensuring surgical success by minimizing psychological and physiological morbidity, enabling early mobilization and optimizing respiratory function. • Successful postoperative analgesia requires preoperative planning, taking into account the nature of the proposed surgery, patient factors and preferences, and their comorbidity. Pain assessment • Adequate analgesia requires regular assessment of pain and the adequacy of analgesia. • The patient’s own subjective experience of pain should always be used • The method of pain assessment varies between institutions. Patient-controlled analgesia • Patient-controlled analgesia involves the use of a preprogrammed pump to deliver a small, predetermined dose of drug, usually an opiate, with a minimum time period between doses • The lock-out period allows the patient to feel the effect of the opiate bolus before administering a subsequent dose, minimizing the amount of opiate consumed and the risk of respiratory depression • Typical regimen would involve 1 mg morphine at 5-minute Patient-controlled analgesia Parenteral and oral opioid regimens • Strong opioids examples include buprenorphine, fentanyl, oxycodone and pethidine, as well as morphine Morphine is the most commonly used, particularly in the postoperative period • Typical regimens of 10 mg morphine, either subcutaneously or orally, as required at 4–6-hour intervals. • Opioid side effects include respiratory depression, dysphoria, constipation, nausea and vomiting, pruritus, urinary retention • Opioids can be reversed with naloxone, an opioid antagonist Weak opioids • Examples of weak opioids, useful in the management of mild pain, include codeine, dihydrocodeine and tramadol. • Codeine are available in preparation with paracetamol. • Tramadol inhibits serotonin and noradrenaline reuptake, and is effective in neuropathic pain as well as in the acute pain setting Paracetamol • Paracetamol is effective in the management of postoperative pain and can be administered by the oral, intravenous and rectal routes • Reduce opioid requirements by 20–30% . • Paracetamol should therefore be prescribed to all postoperative patients Postoperative nausea and vomiting • PONV affects 20–30% of patients. It is very distressing and is a significant factor in causing delayed discharge. • Risk factors include female sex, type of surgery (e.g., gynecological and laparoscopic surgery), not smoking, a history of previous PONV or motion sickness, and opioid use. Anaesthetic technique is also important factor • Management of PONV centers on identifying high-risk patients and instituting preventative measures. • Ondansetron and dexamethasone are particularly effective in the prophylaxis and treatment of PONV. Postoperative care and complications Introduction • There are three phases of patient care following an operation. • Patients who have received a general anaesthetic should be observed in the recovery room until they are conscious and their vital signs are stable. • In general, the anaesthetist exercises primary responsibility for the patient’s cardiopulmonary function and the surgeon is responsible for the operative site, the wound and any surgically placed drains • Monitoring of airway, breathing and circulation is the priority on recovery period. Haemorrhage • Significant blood loss into a surgical drain, particularly if associated with hypovolaemic shock, is an indication for reop • Reactive bleeding is usually caused by a slipped ligature or dislodgement of clot • Superficial bleeding into the surgical wound rarely requires immediate action • Late secondary haemorrhage typically occurs 7–10 days after an operation and is due to infection eroding a blood vessel. • Rigid drain tubes may also occasionally erode a large vessel Surgical ward care (General care) • Monitoring of vital signs and temperature continues on return to the ward along with output from the urinary catheter, naso-gastric tube and surgical drains • Anxiety, disorientation and minor changes in personality, behavior or appearance are often the earliest manifestation of complications. • The abdomen is examined for evidence of excessive distension or tenderness. • The return of bowel sounds and the free passage of flatus reflect recovery of gut peristalsis. • The legs are checked for swelling, discoloration or calf tenderness Tubes, drains and catheters • If a nasogastric tube is in place, it is kept open at all times • It is not necessary to wait until bowel sounds have returned or flatus has been passed. • Nasogastric tubes are uncomfortable and may prevent coughing with expectoration, and so they should not be retained for longer than necessary. • Surgical drains are generally removed when the volume of effluent diminishes. • If a urinary catheter has been placed, it should be removed once the patient is mobile. Fluid balance • Standard intravenous fluid requirement for an adult is 3 L/day, of which 1 L normal saline and 2 L 5% dextrose. • It is not necessary to replace potassium within the first 24–48 hours after surgery, as potassium is released from injured cells and tissues at the surgical site. • Potassium supplements (1 mEq/kg/day) can subsequently be added to intravenous fluids, • Insensible fluid loss should be kept in mind. • A mixed gastric aspirate of 1 L must be replaced by 120 mEq of Na and 10 mEq of K, Balance fluid is replaced by 5% dextrose. • Intravenous fluid therapy is discontinued once oral fluid intake has been established. Blood transfusion • Hemoglobin measurement will be a guide to the need for postoperative blood transfusion. • A full blood count should be undertaken within 24 hours of surgery • Blood is administered if the hemoglobin is less than 80 g/L with a low hematocrit (<24) • Needless transfusion is avoided, unless they have cardiovascular instability. Nutrition • Nutrition in postoperative patients is frequently poorly managed • Enteral or parenteral nutrition is essential if starvation is prolonged. • Enteral nutrition is preferred. • If a prolonged period of starvation is anticipated, feeding jejunostomy tube can be inserted • Dietary intake should be monitored in all patients in the postoperative period, and oral high-calorie supplements given if appropriate General complications • Nausea and vomiting can be caused by surgery and/or anesthesia, and an antiemetic can prove useful and can be considered prophylactically • Transient hiccups in the immediate postoperative period are usually no more than a nuisance Small doses of chlorpromazine may be helpful for persistent cases • Spinal anesthesia may cause headache from leakage of cerebrospinal fluid, and patients should remain recumbent for 12 hours when this occurs. • Sites of cannula insertion should be checked regularly for signs of infection, and the cannula replaced if necessary. Postoperative shock • The three main types are hypovolaemic, cardiogenic and septic shock. • Hypovolaemic shock may be caused by inadequate fluid replacement. • Cardiogenic shock is usually secondary to acute myocardial ischemia/infarction or an arrhythmia. • Hypovolaemic and cardiogenic shock are characterized by tachycardia, hypotension, sweating, pallor and vasoconstriction. • Septic shock is characterized in the early stages by a hyperdynamic circulation with fever, rigors, and a warm vasodilated periphery Postoperative urinary retention • Inability to void postoperatively is common, especially after groin, pelvic or perineal operations, or operations under spinal anaesthesia • Males tend to be more commonly affected • Frequent dribbling or the passage of small volumes of urine may indicate overflow incontinence, and examination may reveal a distended bladder. • The management of acute urinary retention is catheterization of the bladder with removal of the catheter after 2–3 days. Deep venous thrombosis (DVT) • The incidence of DVT varies with the type of operation and the associated risk factors. • Measures to prevent DVT include the use of graded compression support stockings, mechanical or electrical compression of the calf muscles during surgery; and low-molecular-weight heparin. • DVT is frequently asymptomatic, but may present with a painful, tender swollen calf • Duplex ultrasonography is now the investigation of choice. • DVTs are treated with low-molecular-weight heparin injected subcutaneously once daily. Wound complications Infection • Is the most common complication in surgery • The incidence varies from less than 1% in clean operations to 20–30% in dirty cases • The onset is usually within 7 days of operation. • Symptoms include malaise, anorexia, and pain or discomfort at the operation site. • Signs include local erythema, tenderness, swelling, cellulitis, wound discharge or frank abscess formation. • Remove one or more sutures or staples prematurely to allow the egress of infected material. The wound is then allowed to heal by secondary intention. • Antibiotics are only required if there is evidence of associated cellulitis or septicemia. Dehiscence • The incidence of abdominal wound dehiscence (‘burst abdomen’) should be less than 1% • Wound dehiscence may be partial (deep layers only) or complete (all layers, including skin). • The extrusion of abdominal viscera through a complete abdominal wound dehiscence is known as evisceration. • This rare complication usually occurs within the first 2 weeks after operation. • Risk factors include obesity, smoking, respiratory disease, obstructive jaundice, nutritional deficiencies, renal failure, malignancy, diabetes and steroid therapy; However, the most important causes are poor surgical technique. • The wound should be resutured under general anesthesia. • Incisional herniation complicates approximately 25% of cases. REFERENCES • O'Connell, P.R., McCaskie, A.W., & Sayers, R.D. (Eds.). (2023). Bailey & Love's Short Practice of Surgery - 28th Edition • Brunicardi F, & Andersen D.K., & Billiar T.R., & Dunn D.L., & Kao L.S., & Hunter J.G., & Matthews J.B., & Pollock R.E.(Eds.), (2019). Schwartz's Principles of Surgery, 11e. 2 January 2024 129 Thank You 2 January 2024 130