Perioperative Care
Perioperative care encompasses pre-operative assessment, intraoperative management, and post-operative care. Systematic optimisation reduces complications, mortality, and length of stay.
Key Facts
Pre-operative assessment: ASA grade, functional capacity (≥4 METs = low risk), comorbidity optimisation, medication review ASA classification: I (healthy) to V (moribund); ASA ≥III associated with increased perioperative risk Fasting guidelines: Clear fluids up to 2 hours before GA; food/milk up to 6 hours — AAGBI guidelines VTE prophylaxis: Risk-assess all surgical patients; LMWH ± TED stockings (NICE NG89) Enhanced Recovery After Surgery (ERAS): Evidence-based pathway reducing complications and LOS — pre-op optimisation, minimise fasting, epidural/regional, early mobilisation, early oral intake Anticoagulant management: Warfarin — stop 5 days before, bridge with LMWH if high thromboembolic risk; DOACs — stop 24-48 hours before Post-operative complications timeline: Immediate (haemorrhage, anaesthetic), early (infection, DVT/PE, AKI, ileus), late (adhesions, incisional hernia, chronic pain) WHO Surgical Safety Checklist: Mandatory — sign-in, time-out, sign-out; reduces complications and mortality (Haynes et al., NEJM 2009)
Overview
Key Facts
Perioperative care is a multidisciplinary process. Systematic assessment, optimisation, and evidence-based care pathways significantly improve surgical outcomes.
Epidemiology
~4.7 million surgical procedures performed annually in England. ~1 in 4 surgical patients has significant comorbidities. Emergency surgery carries ~10× the mortality of elective surgery. Post-operative complications occur in ~10-20% of cases.
Aetiology
Perioperative complications arise from the interaction of patient factors (comorbidities, functional capacity), surgical factors (complexity, duration, emergency vs elective), and anaesthetic factors.
Pathophysiology
Surgical stress response:
- Tissue injury → neuroendocrine response (cortisol, catecholamines, ADH, aldosterone)
- Catabolic state → protein breakdown, insulin resistance, sodium/water retention
- Inflammatory response → risk of organ dysfunction, wound healing impairment
- ERAS pathways aim to minimise the stress response
Clinical Presentation
Pre-operative Assessment
History:
- Comorbidities: Cardiac, respiratory, renal, hepatic, diabetes
- Functional capacity: Can the patient climb 2 flights of stairs? (≥4 METs)
- Previous surgery and anaesthetic history: MH, difficult intubation
- Medications: Anticoagulants, antiplatelets, antihypertensives, insulin, steroids
- Allergies, smoking, alcohol
- Airway assessment: Mallampati score
ASA Classification:
| Grade | Description |
|---|---|
| I | Healthy patient |
| II | Mild systemic disease |
| III | Severe systemic disease |
| IV | Severe systemic disease, constant threat to life |
| V | Moribund, not expected to survive without surgery |
| E | Emergency (suffix) |
Post-operative Complications
Immediate (0-24 hours):
- Haemorrhage (reactionary), anaesthetic complications (PONV, hypothermia)
Early (1-7 days):
- Surgical site infection, DVT/PE, pneumonia, AKI, urinary retention, paralytic ileus, anastomotic leak
Late (>7 days):
- Wound dehiscence, incisional hernia, adhesions, chronic pain
Differential Diagnosis
| Post-op Day | Complication | Key Investigation |
|---|---|---|
| Day 0-1 | Reactionary haemorrhage | FBC, clinical assessment, return to theatre |
| Day 1-3 | Atelectasis (commonest cause of early fever) | CXR |
| Day 3-5 | Pneumonia, UTI | CXR, urine MC&S |
| Day 5-7 | SSI, anastomotic leak, DVT/PE | Wound assessment, CT, CTPA |
| Day 7+ | PE, abscess, wound dehiscence | CTPA, CT |
| Weeks-months | Incisional hernia, adhesions | CT, clinical |
Diagnosis / Investigation
Pre-operative
- Bloods: FBC, U&Es, LFTs, coagulation, G&S/crossmatch, HbA1c (diabetics)
- ECG: If cardiac risk factors, age >65, ASA ≥III
- CXR: Not routine; only if clinical indication (NICE NG45)
- Echocardiography: If suspected valvular disease, HF symptoms
- CPET: For major surgery in patients with limited functional capacity
- Lung function tests: If COPD/asthma for major thoracic/abdominal surgery
Post-operative Monitoring
- NEWS2: Regular observations
- Fluid balance: Strict I&O
- Drain output: Volume, character
- Blood glucose: 6-hourly in diabetics
Management
Pre-operative
- Consent: Written informed consent; risks, benefits, alternatives
- Fasting: Clear fluids until 2 hours, food until 6 hours before GA (AAGBI)
- Carbohydrate loading: Pre-operative carbohydrate drinks (part of ERAS)
- Medication review:
- Continue: Beta-blockers, statins, anti-epileptics, inhalers, most antihypertensives
- Omit morning of surgery: ACEi/ARBs (risk of intraoperative hypotension), metformin (on day of surgery)
- Warfarin: Stop 5 days pre-op; check INR; bridge with LMWH if high risk
- DOACs: Stop 24-48 hours pre-op (depending on renal function and agent)
- Insulin: Reduce/adjust; VRIII (variable rate insulin infusion) if expected to miss meals
- Steroids: Stress dose hydrocortisone if on long-term steroids (adrenal suppression risk)
Intraoperative
- WHO Checklist: Sign-in, time-out, sign-out — mandatory
- Prophylactic antibiotics: At induction (within 60 minutes of incision)
- Normothermia: Forced-air warming (target >36°C)
- Goal-directed fluid therapy: Optimise cardiac output
Post-operative
- VTE prophylaxis: LMWH (e.g., enoxaparin 40mg SC OD) + TED stockings (NICE NG89)
- Analgesia: Multimodal — paracetamol + NSAID (if safe) + opioid (PRN) ± regional/epidural
- Early mobilisation: Within 24 hours (ERAS)
- Early oral intake: Within 24 hours (ERAS)
- Catheter care: Remove within 24-48 hours if no indication to continue
- Diabetes management: Glucose monitoring; VRIII if needed; early return to usual regimen
Referral Criteria
- Complex comorbidities — anaesthetic pre-assessment clinic
- High-risk patients — consider HDU/ICU bed booking
- Post-operative complications — appropriate speciality review
Prognosis
- Elective surgery mortality: ~0.5-1% overall
- Emergency surgery mortality: ~5-15% (much higher in elderly and ASA ≥III)
- ERAS pathways: Reduce LOS by ~30% and complications by ~20-30%
- WHO Checklist: Reduces mortality by ~47% and complications by ~36% (Haynes 2009)
- VTE: PE is a leading preventable cause of in-hospital death; LMWH reduces DVT risk by ~60%
Other Relevant Information
ERAS Key Components
| Phase | Intervention |
|---|---|
| Pre-operative | Counselling, carbohydrate loading, no prolonged fasting, anaemia correction |
| Intraoperative | Minimally invasive surgery, goal-directed fluids, normothermia, avoid drains/NG where possible |
| Post-operative | Early mobilisation, early oral intake, multimodal analgesia, early catheter removal |
Common Post-operative Medication Adjustments
| Drug | Perioperative Management |
|---|---|
| Metformin | Omit on day of surgery; restart when eating and drinking |
| ACEi/ARB | Omit morning of surgery |
| Warfarin | Stop 5 days before; INR check; bridge with LMWH if indicated |
| DOACs | Stop 24-48 hours before (depends on agent and renal function) |
| Long-term steroids | Give stress-dose hydrocortisone |
| Insulin | Adjust dose; VRIII if prolonged fasting |