Download Preoperative Assessment

Preoperative Assessment
M K Alam
MS; FRCS
ILO’s
• At the end of this presentation students will be
able to:
 Understand the principles of preparing patients
for surgery.
 Describe the systemic approach in preoperative
assessment.
 Name common problems affecting patient’s
fitness for surgery.
 Describe the management of chronic medical
problems.
 Outline DVT prophylaxis measures.
 Describe how to take informed consent.
Introduction
• Careful preoperative assessment essential for
good surgical outcome.
• Assessment modified for emergency surgery.
• Benefit of operation vs no surgery vs no
treatment.
• Decision to operate- patient fitness for surgery
usually decided few weeks before surgery.
• Identify comorbid conditions and optimize it.
• Preoperative clinics before admission for surgery.
Priorities
• Establish extent & severity of condition requiring surgery.
• General medical history.
• Assessment for comorbid and undiagnosed diseases.
• Medications.
• Details of previous surgery and anaesthesia.
• Anaesthetic review before admission.
• Morning of surgery: Reassess with all investigation results.
ASA classification
• ASA 1 - Normal healthy patient
• ASA 2 - Mild systemic disease
• ASA 3 - Severe systemic disease
• ASA 4 - Severe systemic disease, a constant threat to life
• ASA 5 - A moribund patient, not expected to survive
without the operation
• ASA 6 - A declared brain-dead patient whose organs are
being removed for donor purposes
Oxygen
• Postop. Morbidity/ mortality related to O2
delivery to tissues.
• Patients with poor cardiorespiratory reserve
and anaemia at higher perioperative risk.
• Optimizing this- minimizes the risk
Systemic preoperative assessment
CVS
• CVS diseases:
Angina, myocardial ischemia, exertional
dyspnoea, orthopnoea, paroxysmal nocturnal dyspnoea,
dependent oedema, arrhythmia, murmur, hypertension,
antiplatelet and anticoagulant drugs.
• Cardiology consultation.
• Optimization before surgery.
Respiratory system
• New cough, sputum or wheeze- new or exacerbation of preexisting respiratory disease.
• Asthmatics or COPD with purulent sputum- infective exacerbation.
• Respiratory viral illness- postpone surgery if possible.
• Smoking- advise to quit.
• Functional reserve: How many stairs can climb before needing rest?
• ABG, respiratory function test.
• Pulmonologist consultation
Nutritional status
• BMI, weight
• History of weight loss.
• Malnutrition:
Low BMI- less than predicted
> 20% weight loss
Hypoproteinaemia
Hypoalbuminaemia
• Delay surgery to treat malnutrition if possible
• Obesity: Increased risk from surgery & anaesthesia.
Advise: Reduce weight (dietician referral, supervised exercise)
Medications
• Long term steroids: needs higher dose during perioperative
period. 100mg Hydrocortisone every 6 hours.
Gradually reduced in postoperative period.
• Antiplatelet drugs: Aspirin, clopidogrel should be withdrawn
only after cardiology consultation.
• Warfarin: Stopped 4-5 days before surgery, started on IV
unfractionated heparin or subcutaneous low molecular
weight heparin. Warfarin restarted after risk of bleeding is
over. Heparin stopped once INR is in therapeutic range (2.5-3)
• Psychiatric medications can complicate anaesthesia.
Anaesthetist informed. MAOI stopped 2-3 weeks
before surgery.
• Allergies
• Pregnancy- if surgery is necessary,
safe period- 2nd trimester.
• Previous surgery & anaesthesia details.
Preoperative investigations
• Identify new problems to correct before surgery.
• Fitness for anaesthesia
• Avoid unnecessary tests
Investigations
•
•
•
•
•
•
•
FBC, Coagulation profile,
Cross match group & save.
Urea, electrolytes, LFTs
Microbiology- urine culture, sputum, virology
Imaging: CXR, US, CT, MRI, Isotope studies
RFT: ABG, FVC, FEV1 (Pulmonology consultation)
CVS: ECG, Echocardiography, Thallium scan,
exercise testing. (Cardiology consultation)
High risk patients
•
•
•
•
•
•
•
HBV, HCV patients
HIV patients
Patients with unknown HBV,HCV,HIV status.
IV drug users
Recipients of multiple transfusion.
Patients from endemic area.
Universal precaution to protect surgical team.
Emergency surgery
• Assessment curtailed due to lack of time.
• Frequently need resuscitation before surgery.
• ABC approach.
• Restore hypovolemia before surgery (except for
life threatening bleeders).
• Avoid delaying surgery to correct moderate
biochemical abnormalities.
Risk factors for VTE
•
•
•
•
•
•
•
•
•
Malignancy
Age > 60 years
Dehydration
Past or family history of VTE
Obese
Significant comorbidity (CVS, RS, metabolic)
HRT, oestrogen containing contraceptives.
Pelvic or lower limb surgery
Surgery time > 90 min.
Preoperative round
• Consent: Full explanation, patient’s all questions answered.
• Patient fully understands (simple language)
• All treatment options explained.
• All potential serious outcome explained, even if rare.
• Risk & benefit quantified.
• Surgeon or his deputy (knowledgeable, experienced) to explain.
• Respect patients decision.
• No pressure to accept recommendation.
• Check all chronic/ acute conditions optimized.
• DVT prophylaxis:
Anti embolic stockings,
Intermittent pneumatic compression device
Heparin (LMWH, unfractionated)
• Antibiotic prophylaxis.
• Anxiolytics
• Preoperative fasting- average 6 hours
Perioperative management of chronic disease
• CVS disease: Cardiology assessment. Antibiotic for
valvular disease (BE prophylaxis) Pacemaker- avoid
monopolar diathermy. Bipolar or ultrasonic devices
preferred.
• RS: Chest physician consultation.
May need HDU/ ICU- arrange bed in consultation with anaesthetist.
Pre/postop. chest physio.- incentive spirometry + good analgesia
Perioperative management of chronic disease
• Diabetes: Poor glycaemic control is associated with increased
complication. Surgery → hyperglycaemia. Needs close monitoring.
• Glucose level- 6-10 mmol /L reasonable target.
• Management:
• Mild cases- omit oral hypoglycaemic drug on morning of surgery, monitor
sugar level postop until eating freely (mild cases).
If glucose > 10mmol/L- start glucose/insulin/K⁺ infusion
• Insulin dependent: Start glucose/ insulin/ K⁺ prior to surgery. Convert tos.c short acting insulin then regular insulin as the diet is introduced.
Chronic renal failure
• Dialysis dependent: Careful IV fluid administration.
• Care of dialysis access- PDC, venous fistula
• Venous fistula- never use for venous access/ phlebotomy.
• Preoperative dialysis to optimize patient.
• Non-dialysis dependent: Reasonable renal function.
• Avoid: Nephrotoxic drugs, hypotension, treat sepsis
aggressively and maintain careful fluid balance.
Jaundice
• Mostly obstructive, may be hepatocellular
• Coagulopathy due to Vit K dependent factor
deficiency (II,VII,IX,X).
• Coagulopathy corrected by FFP.
Anticoagulant therapy
• Warfarin stopped 4-5 days before surgery.
• Started on IV unfractionated heparin or S.C. LMWH.
• INR before surgery <1.5
• Warfarin restarted after risk of bleeding is over,
concurrent with heparin.
• Heparin stopped once INR 2.5-3.
Anaemia
• Mostly iron deficiency due to GI bleeding or
menorrhagia.
• Preoperative haemoglobin around 10 G/ dl
• If major blood loss expected- cell salvage
technique
Thank you!