Preoperative Assessment Taylors University PDF

Dr Gnandev Phutane Associate Professor Anaesthesia and Critical Care Taylors University Hospital Sungai Buloh Selangor  Reduce the patient’s surgical and anesthetic perioperative morbidity or mortality, and to return him to desirable functioni...

Dr Gnandev Phutane Associate Professor Anaesthesia and Critical Care Taylors University Hospital Sungai Buloh Selangor  Reduce the patient’s surgical and anesthetic perioperative morbidity or mortality, and to return him to desirable functioning as quickly as possible. A history and physical examination, focusing on risk factors for cardiac and pulmonary complications and a determination of the patient’s functional capacity, are essential to any preoperative evaluation.  Laboratory investigations should be ordered only when indicated by the patient’s medical status, drug therapy, or the nature of the proposed procedure and not on a routine basis.  Those with comorbidity should be optimized for the procedure.  Proper consultations with appropriate medical services should be obtained to improve the patient’s health 1. Evaluate the patient’s medical condition from medical history, physical examination, investigations and, when appropriate, past medical records. 2. Optimise the patient’s medical condition for anaesthesia and surgery. 3. Determine and minimise risk factors for anaesthesia. 4. Plan anaesthetic technique, peri-operative care, post operative care 5. Develop a rapport with the patient to reduce anxiety and facilitate a safe conduct of anaesthesia. 6. Inform and educate the patient about anaesthesia, peri-operative care and pain management 7. Obtain an informed consent for anaesthesia. 1. The pre-anaesthetic assessment should be performed by the anaesthesiologist who is giving the anaesthesia. 2. If this is not possible, a satisfactory mechanism is required whereby the findings of the pre- anaesthetic assessment can be conveyed to the anaesthesiologist concerned. 3. The pre-anaesthetic assessment should be performed at an appropriate time before the scheduled surgery to allow adequate preparation of the patient. 4. This also applies to day care surgery patients. 5. Pre-operative admission is indicated in patients who require further medical evaluation or intervention prior to a major surgery. 6. Admission should not be merely for pre-operative investigations which can be done as out-patient. 7. The pre-anaesthetic assessment may be conducted: a) As a personal interview in the ward, operating theatre(induction room) or pre-anaesthetic clinic. b) Using pre-set questionnaire assisted by trained nursing or paramedical staff under the supervision of an anaesthesiologist. 8. Input from other medical specialties may be required in the pre-anaesthetic management of the patient. However, only the anaesthesiologist may determine a patient’s fitness to undergo anaesthesia. 9. In the case of emergency surgery where early consultation is not always possible, the anaesthesiologist is still responsible for the pre- anaesthetic assessment. 10. If surgery cannot be delayed in view of increased anaesthetic risks, documentation to this effect should be made. Most important component of the preoperative evaluation. The history should include:  A past and current medical history  A past surgical history and outcome  A family history of anaesthetic complications  A social history (use of tobacco, alcohol and illegal drugs, lifestyle changes)  A history of allergy, current and recent drug therapy, unusual reactions or responses to drugs and  Any problems or complications associated with previous anesthetics. In children, the history should also include  Birth history, focusing on risk factors such as prematurity at birth  Perinatal complications  Congenital chromosomal or anatomic malformations  History of recent infections, particularly upper and lower respiratory tract infections  The history should include a complete review of systems to look for undiagnosed disease or inadequately controlled chronic disease.  Diseases of the cardiovascular and respiratory systems are the most relevant in respect of fitness for anesthesia and surgery  General ◦ Weight ◦ Height ◦ Temperature ◦ Vital Signs  Airway assessment  Systemic examination  Site of regional block( Spine, deformities)  Airway maintenance is fundamental to safe anaesthetic practice.  During pre-operative assessment, it is imperative to identify patient who may pose problem in airway management.  Patients with potential difficult airway ◦ Obesity ◦ Pregnancy esp. pre-eclampsia ◦ Anatomical abnormalities  Micrognathia/ Macrognathia  Macroglossia  Congenital Syndrome (e.g., Pierre-Robin, Treacher – Collins)  Burns contracture involving head and neck  Evidence of upper airway obstruction – Tumour or edema involving upper airway – Large goitre – Acute epiglotitis – Maxillofacial trauma – Airway burns Cervical spine problem – Fracture dislocation – Subluxation – Rheumatoid Arthritis – Ankylosing Spondylitis  History of radiotherapy to head and neck region especially the oral cavity  History of difficult intubation previous anaesthetics ◦ Examine past anaesthesia records if available to look for cause(s) of difficult intubation  Predictors of difficult intubation – Obese – Buckteeth – Large tongue – Reduced jaw movement – Receding chin – Neck swelling – Tracheal deviation – Patern of respiration  Take very seriously history of prior difficulty  Head and neck movement (extension) ◦ Alignment of oral, pharyngeal, laryngeal axes ◦ Cervical spine arthritis or trauma, burn, radiation, tumor, infection, scleroderma, short and thick neck Physical examination ◦ Anatomic variation ◦ Mouth  Opening < 3 Finger breadth  Poor dentition( ugly duckling)  Macro-glasia ◦ Neck  Hyoid mental distance < 3cm  Thyro-mental distance < 6.5 cm  Cervical spine mobility < 350  Post tracheostomy Assessment Methods: 1. Mallampati Score Classification 2. Wilson Risk Sum Score 3. Cormack & Lehane Score Classification  Oropharyngeal visualization  Mallampati Score  In sitting position, protrude the tongue, don’t say “AHH”  This is another scoring system, devised by Wilson et al in 1988 ◦ Based on various parameters obtained during preoperative assessment Risk Factor Level Point Weight < 90 kg 0 90 – 110kg 1 >110kg 2 Head and neck >90 degree 0 movement About 90 degree 1 0 0 IG < 5cm, Slux =0 1 IG < 5cm, Slux 15% Coagulation Profile Haematological disease Liver disease Anticoagulation Intra-thoracic/Intra-cranial procedures Random Blood Sugar Age above 60 Diabetes Mellitus Liver dysfunction Liver Function Tests Hepatobiliary disease Alcohol abuse Note: For healthy patients undergoing short, minimally invasive procedures, investigations may not be necessary.  A history of medication use should be obtained in all patients.  Generally, administration of most drugs should be continued up to and including the morning of operation, although some adjustment in dosage may be required (e.g., antihypertensives, insulin).  The monoamine oxidase inhibitors should be withdrawn 2-3 weeks before surgery because of the risk of interactions with drugs used during anesthesia.  The oral contraceptive pill should be discontinued at least 6 weeks before elective surgery because of the increased risk of venous thrombosis.  Herbal medication need to be stopped 2 weeks before anaesthesia.  Perioperative risk is a function of the preoperative medical condition of the patient, the invasiveness of the surgical procedure and the type of anesthetic administered.  The ASA grading system was introduced originally as a simple description of the physical state of a patient.  It is extremely useful and should applied to all patients who present for surgery.  Increasing physical status is associated with increasing mortality.  Emergency surgery increases risk dramatically, especially in patients in ASA class 4 and 5. Class Definition Mortality Rate A normal healthy patient. 1 0.06%~0.08% A pt with mild systemic disease and no functional limitations. 2 1. well-controlled HPT/DM 2. H/O Asthma 0.27%~0.4% 3. Anemia 4. Smoking 5. Mild Obesity 6. Age < 1 or >70 yrs. 7. Pregnancy Class Definition Mortality Rate ~a pt with moderate to severe systemic disease & some functional limitation. 3 1. Status post MI. 1.8%~4.3% 2. Angina. 3. Poorly controlled HPT. 4. Symptomatic resp disease. 5. Massive obesity. ~a pt with severe systemic disease that is a constant 4 threat to life and functionally incapacitating. 7.8%~23% 1. Unstable angina. 2. CCF. 3. Debilitating resp: disease. 4. Hepatorenal failure. Class Definition Mortality Rate ~ A moribund pt who is not expected to survive 24 h with/out 5 surgery. 9.4%~51% 6 ~ A brain –dead patient whose organs are being harvested. E ~If the procedure is an emergency Class Definition 1 No limitations of physical activity. 2 Slight limitation of physical activity but comfortable at rest. 3 Marked limitation of physical activity. Less than ordinary activity causes fatigue, palpitation, dyspnoea or anginal pain. 4 Inability to carry on any physical activity without discomfort. Symptoms of cardiac insufficiency or of the anginal syndrome may be present even at rest. Class Mortality I 4.30% II 10.6% III 25.0% IV 67.0%  Goldman’s Multifactorial Cardiac Risk Index  Lee’s Revised Cardiac Risk Index REVISED CARDIAC RISK INDEX (Circulation 1999; 100:1043-1049)  Variables Points ► History. 1. MI < 6/12. 10 2. Age > 70 5 ► Physical examination 1. S3 gallop rhythm or raised 11 JVP. 2. Severe aortic stenosis 3 ► ECG 1. Rhythm other than SR(+ 7 Premature atrial contraction). 2. >5 PVC / minute 7  Variables Points ► Biochemistry : 1. PaO2 < 60 mmHg. 2. PaCO2 > 50 mmHg. 3. Urea > 6.5 mmol/l 3 4. K < 3.0 mmol/l. 5. HCO3 < 20 mmol/l. 6. Cr > 3 mg/dl ► Surgery 1. Emergency 4 2. Peritoneal / thoracic/aortic surgery 3  Risk Morbidity% Mortality% according to score I (0-5 points) 0.7% 0.2% II (6-12 points) 5% 2% III (13-25 points) 11% 2% IV (>26 points) 22% 56% I Normal. II Critical. III Needs specific consult for cardiac problems. IV Surgery not justified. 1. High risk surgery (cardiac risk >5%): 1 Point 2. Coronary Artery Disease : 1 Point I. History of MI II. Positive stress test III. Chest pain due myocardial ischemia IV. Current use of nitrates V. Pathologic Q waves on ECG 3. Congestive Heart Failure : 1 Point I. Pulmonary edema II. Paroxysmal nocturnal Dyspnea III. Bibasal crypts IV. S3 Gallop rhythm V. CXR demonstrating pulmonary vascular congestion 4. Cerebrovascular Disease (TIA or CVA): 1 Point 5. DM on insulin : 1 Point 6. Serum Creatinine >2.0 mg/dl: 1 Point  ◦ Points 0: Class I Very Low (0.4% complications) ◦ Points 1: Class II Low (0.9% complications) ◦ Points 2: Class III Moderate (6.6% complications) ◦ Points 3: Class IV High (>11% complications)  Complications predicted by above scoring ◦ Myocardial Infarction ◦ Pulmonary Embolism ◦ Ventricular Fibrillation ◦ Cardiac Arrest ◦ Complete Heart Block  Functional capacity can be expressed in metabolic equivalent (MET) levels  Multiples of the baseline MET value can be used to express aerobic demands for specific activities.  One MET represents the oxygen consumption of a resting adult (3.5 ml/kg/min).  Perioperative cardiac and long-term risks are increased in patients unable to meet a 4-MET demand during most normal daily activities. CARDIOLOGICAL REFERRAL Exercise Any 4 MET 4 METs Tolerance SURGICAL Cardiac risk RISK MAJOR INTERMEDIATE MINOR High Refer Refer Refer Refer Operate Intermediat Refer Refer Operate Operate Operate e Low Refer Operate Operate Operate Operate  A careful history taking and physical examination are the most important parts of preoperative pulmonary risk assessment. The role for preoperative pulmonary function testing remains uncertain. No data suggest that spirometry identifies a high- risk group that would not otherwise be predicted by the history and physical examination. Spirometry may be useful when there is uncertainty about the presence of lung impairment. It should be used selectively when the information it provides will change management or improve risk stratification.  Develops in 5% to 10% of patients undergoing major non-cardiothoracic surgery and in 22% of high-risk patients.  As many as 1 in 4 deaths occurring within a week of surgery are related to pulmonary complications  More frequent than cardiac complications  Postoperative pulmonary complications (PPCs) such : hypoxemia pneumonia atelectasis bronchitis bronchospasm respiratory failure with prolonged mechanical ventilation or exacerbation of underlying chronic lung disease, increase patient morbidity and mortality and prolong the length of hospital stay after surgery. Regional Anesthesia in the Patient Receiving Antithrombotic or Thrombolytic Therapy: ASRA Evidence-Based Guidelines (Third Edition) 2010  Regional Anesthesia in the Patient Receiving Antithrombotic or Thrombolytic Therapy: American Society of Regional Anesthesia and Pain Medicine Evidence-Based Guidelines (Third Edition) Horlocker, Terese T.; Wedel, Denise J.; Rowlingson, John C.; Enneking, F. Kayser; Kopp, Sandra L.; Benzon, Honorio T.; Brown, David L.; Heit, John A.; Mulroy, Michael F.; Rosenquist, Richard W.; Tryba, Michael; Yuan, Chun-Su Regional Anesthesia and Pain Medicine. 35(1):64-101, January/February 2010. doi: 10.1097/AAP.0b013e3181c15c70 Perioperative Management of Patients on Antiplatelet Therapy Copyright © 2012 Regional Anesthesia and Pain Medicine. Published by Lippincott Williams & Wilkins. 68 Chassot et al, 2007; ‘Perioperative antiplatelet therapy: the case for continuing therapy in patients at risk of myocardial infarction’; BJA 99 (3): 316 -28; 2007.  Regional Anesthesia in the Patient Receiving Antithrombotic or Thrombolytic Therapy: American Society of Regional Anesthesia and Pain Medicine Evidence-Based Guidelines (Third Edition) Horlocker, Terese T.; Wedel, Denise J.; Rowlingson, John C.; Enneking, F. Kayser; Kopp, Sandra L.; Benzon, Honorio T.; Brown, David L.; Heit, John A.; Mulroy, Michael F.; Rosenquist, Richard W.; Tryba, Michael; Yuan, Chun-Su Regional Anesthesia and Pain Medicine. 35(1):64-101, January/February 2010. doi: 10.1097/AAP.0b013e3181c15c70 Perioperative Management of Patients on Warfarin Copyright © 2012 Regional Anesthesia and Pain Medicine. Published by Lippincott Williams & Wilkins. 70  Regional Anesthesia in the Patient Receiving Antithrombotic or Thrombolytic Therapy: American Society of Regional Anesthesia and Pain Medicine Evidence-Based Guidelines (Third Edition) Horlocker, Terese T.; Wedel, Denise J.; Rowlingson, John C.; Enneking, F. Kayser; Kopp, Sandra L.; Benzon, Honorio T.; Brown, David L.; Heit, John A.; Mulroy, Michael F.; Rosenquist, Richard W.; Tryba, Michael; Yuan, Chun-Su Regional Anesthesia and Pain Medicine. 35(1):64-101, January/February 2010. doi: 10.1097/AAP.0b013e3181c15c70 Neuraxial* Anesthesia in the Patient Receiving Thromboprophylaxis Copyright © 2012 Regional Anesthesia and Pain Medicine. Published by Lippincott Williams & Wilkins. 71  Regional Anesthesia in the Patient Receiving Antithrombotic or Thrombolytic Therapy: American Society of Regional Anesthesia and Pain Medicine Evidence-Based Guidelines (Third Edition) Horlocker, Terese T.; Wedel, Denise J.; Rowlingson, John C.; Enneking, F. Kayser; Kopp, Sandra L.; Benzon, Honorio T.; Brown, David L.; Heit, John A.; Mulroy, Michael F.; Rosenquist, Richard W.; Tryba, Michael; Yuan, Chun-Su Regional Anesthesia and Pain Medicine. 35(1):64-101, January/February 2010. doi: 10.1097/AAP.0b013e3181c15c70 Continued. Copyright © 2012 Regional Anesthesia and Pain Medicine. Published by Lippincott Williams & Wilkins. 72  Pulmonary aspiration of gastric contents, even 30-40 mls, is associated with significant morbidity and mortality Factors predisposing to regurgitation and pulmonary aspiration; – Inadequate anaesthesia – Pregnancy – Obesity – Difficult airway – Emergency surgery – Full stomach – Altered GI motility  Note the list of drugs the patient taking.  Keep a note on drug -drug interaction e.g. patients on SSRI- avoid tramadol or meperidine.- to prevent serotonin syndrome- anxiety, restlessness, hyperreflexia, clonus with rhabdomyolysis and may lead to organ failure- supportive mx and chlorpromazine. Clinical manifestation of excess serotonin in the central nervous system, resulting from the therapeutic use or overdose of serotonergic drugs. Characterised by a triad of clinical features: neuromuscular excitation, autonomic effects, and altered mental status.  Better described as a spectrum of toxicity, ranging from mild to severe, rather than a 'syndrome'.  Diagnosis is clinical and should be based on the Hunter Serotonin Toxicity Criteria (HSTC), of which clonus is a key diagnostic feature.  Treatment is guided by the severity of toxicity and involves cessation of the drug(s), supportive care, and anti- serotonergic drugs in select patients.   Atypical anti psychotics, corticosteroids, atenolol, propranolol, metoprolol, thiazides, proteas inhibitors can produce hyperglycaemia. (assessment of Met acidosis BMJ 2019)  Clear Fluids are emptied from the stomach in an exponential manner with a half life of 10- 20 minutes. This results in complete clearance within 2 hour of ingestion  Gastric emptying of solids is much slower than for fluids and is more variable Drugs commonly used ◦ *Benzodiazepine ◦ *Opioids ◦ Anticholinergic ◦ H2 Blocker *Both are avoided in extreme age patients, upper airway obstruction, severe pulmonary & heart disease & unstable patients  The pre-anaesthetic assessment should  Include confirmation with the patient, the patient’s guardian in the case of children below 18 years or the intellectually challenged, of the nature of the anaesthetic procedure and his / her consent for anaesthesia.  In an emergency, it is often not practical to delay life-saving procedures on account of the issue of consent.  Sufficient information should be provided during the preoperative visit to allow the patient to make a considered decision  These should be discussed with the patient: ◦ The planned anaesthetic procedure ◦ Alternative anaesthetic options, if applicable ◦ Possible risks and complications pertaining to anaesthesia ◦ Benefits versus risks  A written summary of the pre-anaesthetic assessment, orders or arrangements should be explicitly and legibly documented in the patient’s anaesthetic record. Preoperative – I,E,HEMI,COPT Introduction & Explanation of role History Examination Medications and allergies Investigations Consent (check surgical and verbal anaesthetic) Optimise the patient condition Premedication Transfer to theatre – bed/chair/oxygen etc Intraoperative – (Aims) – HONE Haemodynamic stability Optimal fluid management Normocarbia, Normoglycaemia, Normothermia, Normoxia Excellent pain control Postoperatively – ABCD, AFTER Airway Breathing Circulation Drugs, Disability, DVT prophylaxis GOOD LUCK FOR A SAFE PATIENT 1. Recommendations of preanesthethic assessment , Chapter of Anesthesiology , Academy of Medicine ,1998 (CPG) 2. Recommendations of safety standards and monitoring during anesthesia and recovery, revised 2008, Chapter of Anesthesiology , Academy of Medicine ,1998 (CPG) 3. Guidelines on preoperative fasting ,revised 2008, Chapter of Anesthesiology , Academy of Medicine ,1998 (CPG) 4. Roizen MF: Preoperative evaluation. Anesthesia 3rd edition. Churchill Livingstone 1990; 743-772 5. ASRA evidence based guidelines, Third Edition 2010 6. Kerridge R, Lee A, Latchford E, Beehan SJ, Hillman KM. The Perioperative System: A new approach to managing elective surgery. Anaesth Intensive Care 1995; 23: 591-6 7. ANZCA College Policy Document Review P7 (1992): The Pre- anaesthetic consultation 8. ACC/AHA Task Force Report. Guidelines for perioperative cardiovascular evaluation for noncardiac surgery. Circulation 1996; 93: 1278-1317 9. A.Zambouri.Preoperative evaluation and preparation of anesthesia for surgery. Hippokratia. 2007 Jan-Mar; 11(1): 13–21.