12. Postoperative period and complications

1. Definition

• Postoperative period → from the end of the operation to full recovery of working capacity
• Phases:
  1. Early → first 3–5 days
  2. Late → until discharge
  3. Remote → after discharge, until recovery
• Uncomplicated course → normal response to surgical trauma
• Complicated course → a complication develops

2. Clinical observation and patient care

Monitoring

• Observations → pulse, blood pressure, respiratory rate, oxygen saturation, temperature
• Early warning score (NEWS2) → triggers medical review
• Consciousness, pain score
• Fluid balance → input, urine output (> 0.5 mL/kg/h), drains, nasogastric aspirate
• Wound and drains → bleeding, discharge
• Bowel function → flatus, bowel sounds, stool
• Laboratory → full blood count, urea, electrolytes, C-reactive protein (CRP)

Care

• Analgesia → multimodal: paracetamol, NSAIDs, opioids, epidural, regional blocks
• Fluids → stop intravenous fluids once drinking
• Early mobilisation → day 0–1
• Breathing exercises, incentive spirometry, physiotherapy
• Early oral feeding
• Venous thromboembolism (VTE) prophylaxis → low molecular weight heparin, stockings, intermittent pneumatic compression
• Antiemetics
• Glucose control in diabetics
• Remove catheters, lines and drains early
• Enhanced Recovery After Surgery (ERAS) → bundle of these measures; shorter stay, fewer complications

Normal postoperative findings

• Mild fever < 38 °C in the first 48 h → response to surgical trauma
• Raised CRP and white cell count, peaking on day 2–3
• Paralytic ileus for 24–72 h after laparotomy
• Water and sodium retention for 24–48 h → low urine output

3. Classification of complications

By time

• Immediate → within 24 h: primary or reactionary haemorrhage, shock, atelectasis, anaesthetic complications
• Early → days 2–30: infection, anastomotic leak, VTE, pneumonia, ileus
• Late → after 30 days: incisional hernia, adhesions, strictures, scars

By origin

• General → from surgery and anaesthesia in any operation
• Specific → from a particular operation (bile leak after cholecystectomy)

Clavien-Dindo classification

1. Grade I → deviation from normal course without specific treatment
2. Grade II → drugs, blood transfusion, total parenteral nutrition
3. Grade III → surgical, endoscopic or radiological intervention (IIIa without, IIIb under general anaesthesia)
4. Grade IV → life-threatening, intensive care (IVa single organ, IVb multi-organ)
5. Grade V → death

4. Complications by system

Fever timeline (5 W's)

1. Wind → days 1–2; atelectasis, pneumonia
2. Water → days 3–5; urinary tract infection
3. Wound → days 5–7; wound infection
4. Walking → days 5–10; deep vein thrombosis (DVT), pulmonary embolism (PE)
5. Wonder drugs → any time; drug fever, transfusion reaction
6. Day 5–7 with abdominal signs → anastomotic leak, intra-abdominal abscess

Wound

• Haematoma, seroma
• Surgical site infection → redness, pain, discharge; open and drain
• Dehiscence → burst abdomen day 7–10; salmon-pink serous discharge is the warning sign
• Incisional hernia → late

Respiratory

• Atelectasis → most common early complication; physiotherapy, analgesia
• Pneumonia, aspiration
• Pleural effusion
• Acute respiratory distress syndrome (ARDS)
• Pulmonary embolism

Cardiovascular

• Haemorrhage → primary, reactionary, secondary
• Hypotension, shock
• Myocardial infarction, arrhythmias (atrial fibrillation)
• DVT and PE → prevention with mechanical and drug prophylaxis

Gastrointestinal

• Nausea and vomiting
• Paralytic ileus → nasogastric decompression, fluids, correct potassium
• Early adhesive obstruction
• Anastomotic leak → days 5–7; sepsis, peritonitis; CT, drainage or relaparotomy
• Clostridioides difficile colitis

Urinary

• Urinary retention → catheter
• Urinary tract infection
• Acute kidney injury → hypovolaemia, sepsis, nephrotoxic drugs

Neurological

• Postoperative delirium → elderly; exclude hypoxia, sepsis, drugs, retention
• Stroke

Other

• Pressure ulcers
• Line infection, thrombophlebitis
• Fluid and electrolyte disturbances → hypokalaemia, hyponatraemia
• Hyperglycaemia

5. Prevention

• Preoperative optimisation → stop smoking, treat anaemia, nutrition, glucose, cardiac and lung disease
• Antibiotic prophylaxis → within 60 min before incision
• Careful surgical technique and haemostasis
• VTE prophylaxis
• Early mobilisation, physiotherapy
• ERAS pathways