Perforated viscus

Surgical approach

• Aim: control contamination, treat source, washout, restore GI continuity (or divert), and drain
• Typical operations (depend on site/cause)
  • Perforated peptic ulcer: laparoscopic/open exploration → omental (Graham) patch ± biopsy, peritoneal lavage, drains selectively
  • Small bowel perforation (e.g. ischaemia, typhoid, trauma): resection of non-viable bowel ± primary anastomosis vs stoma, washout
  • Appendiceal perforation: appendicectomy ± washout, consider drainage if abscess
  • Diverticular perforation: Hartmann’s procedure vs resection + primary anastomosis ± defunctioning ileostomy, laparoscopic lavage in selected cases
  • Colonic malignancy perforation: oncological resection often with stoma, damage control if unstable
• Approach: laparoscopy if stable/early disease, open laparotomy common in diffuse peritonitis, haemodynamic instability, gross contamination, or uncertain diagnosis
• Damage control surgery (DCS) in profound shock: abbreviated laparotomy, rapid source control, temporary abdominal closure, ICU resuscitation, planned re-look

Anaesthetic management (overview)

• Type of anaesthesia: General anaesthesia with endotracheal intubation
  • RSI usually indicated (full stomach, ileus, opioids, sepsis-related gastroparesis)
  • Avoid SGA (aspiration risk, need for controlled ventilation, pneumoperitoneum/Trendelenburg, potential for prolonged surgery)
• Duration: typically 1–4+ hours (longer if laparotomy, extensive contamination, resection/stoma, DCS/re-look)
• How painful: moderate–severe (laparotomy &gt, laparoscopy), high opioid requirement unless multimodal/neuraxial used
• Key physiological problems: hypovolaemia (third spacing), sepsis/vasodilation, metabolic acidosis, AKI risk, aspiration risk, coagulopathy, hypothermia
• Monitoring/lines: consider arterial line early, 2 large-bore IVs, central access if vasoactive infusions/poor access, urinary catheter, temperature monitoring
• Post-op destination: HDU/ICU common (sepsis, vasopressors, ventilation, lactate/acidosis, frailty/comorbidity, major laparotomy)

Definition and causes

• Perforated viscus = full-thickness breach of GI tract (or biliary) with leakage of gas/contents → peritonitis ± sepsis
• Common causes
  • Upper GI: perforated peptic ulcer (H. pylori, NSAIDs, steroids), iatrogenic (endoscopy)
  • Small bowel: obstruction/closed loop, ischaemia, inflammatory bowel disease, infection, trauma
  • Lower GI: diverticulitis, malignancy, stercoral perforation, IBD, iatrogenic (colonoscopy), anastomotic leak
• Physiology: contamination → inflammatory cascade → capillary leak/third spacing → hypovolaemia, bacterial translocation/endotoxin → vasodilation, myocardial depression, distributive shock, ileus → aspiration risk

Presentation and diagnosis (anaesthetic relevance)

• Symptoms/signs: sudden severe abdominal pain, guarding/rigidity, peritonism, fever, tachycardia, hypotension, confusion, may be subtle in elderly/immunosuppressed
• Investigations
  • Bloods: FBC, U&amp,E/creatinine, LFT, CRP, coagulation, venous/arterial gas (lactate, base deficit), group &amp, save/crossmatch
  • Imaging: CT abdomen/pelvis with contrast often diagnostic, erect CXR may show free air (not always)
• Risk stratification: sepsis screening, consider P-POSSUM/NELA context for laparotomy, frailty and physiological reserve matter

Pre-operative priorities (time-critical)

• Resuscitate in parallel with surgical decision-making (do not delay source control in deteriorating patient)
• Sepsis management (Sepsis Six principles adapted to theatre pathway)
  • Oxygen as needed, target SpO2 appropriate to patient (avoid hyperoxia in some COPD but prioritise perfusion/oxygen delivery)
  • Blood cultures and lactate, repeat lactate for response
  • IV broad-spectrum antibiotics within 1 hour of recognition (follow local policy, include anaerobic cover, consider antifungal if high risk/ICU guidance)
  • IV fluids: balanced crystalloid boluses guided by response, early vasopressors if fluid-refractory hypotension
  • Monitor urine output (catheter), target ≥0.5 mL/kg/h (contextual)
• Aspiration risk reduction
  • NG tube for decompression if vomiting/obstruction/ileus (does not eliminate aspiration risk)
  • Consider non-particulate antacid ± H2 blocker/PPI per local practice (do not delay theatre)
• Optimise physiology: correct severe electrolyte derangements (K+, Ca2+), treat hypoglycaemia, start warming, consider stress-dose steroids if chronic steroids/adrenal insufficiency
• Consent/communication: high-risk emergency laparotomy discussion, blood products availability, ceilings of care and ICU plan

Anaesthetic technique (details)

• Induction: haemodynamically cautious RSI
  • Pre-induction: resuscitate, A-line if time/feasible, vasopressor ready (metaraminol/phenylephrine boluses, noradrenaline infusion early if septic shock)
  • Induction agents: ketamine or etomidate often suitable in shock, titrated propofol if stable, consider opioid-sparing if hypotensive
  • Paralysis: rocuronium (with sugammadex available) or suxamethonium, consider hyperkalaemia/neuromuscular disease contraindications
  • Cricoid pressure: apply if trained assistant, release if impedes ventilation/intubation, prioritise oxygenation and first-pass success
• Maintenance: volatile or TIVA, controlled ventilation, avoid excessive PEEP if hypotensive, lung-protective ventilation (6–8 mL/kg IBW) especially in sepsis
• Monitoring: standard + invasive BP, consider cardiac output monitoring in high-risk laparotomy, frequent blood gases (lactate, Hb, electrolytes)
• Fluids and haemodynamics
  • Balanced crystalloid for initial resuscitation, avoid chloride load where possible, reassess after each bolus (stroke volume response, BP, cap refill, lactate trend, urine output)
  • Early vasopressors for distributive shock, target MAP ~65 mmHg (individualise: chronic HTN, cerebral perfusion)
  • Blood: crossmatch if major laparotomy/anaemia/bleeding risk, transfuse guided by Hb, physiology, ongoing losses, consider cell salvage if contamination policy allows (often avoided in gross faecal contamination)
• Analgesia (multimodal)
  • Opioids: titrate carefully in shock, consider fentanyl/alfentanil boluses, morphine cautiously if hypotensive/renal impairment
  • Paracetamol IV if not contraindicated, NSAIDs often avoided (AKI risk, sepsis, hypovolaemia, perforated ulcer context)
  • Regional: epidural may be excellent for open laparotomy but often limited by sepsis, coagulopathy, urgency, anticoagulation, haemodynamic instability, consider alternative (TAP blocks, rectus sheath, wound catheters)
  • Ketamine infusion (analgesic dose) can reduce opioid and support haemodynamics, lidocaine infusion sometimes used (local policy, contraindications)
• Antibiotics: ensure given pre-incision, re-dose intra-op if prolonged/major blood loss as per guidelines
• Temperature and glucose: active warming (forced air, warmed fluids), avoid hypothermia-related coagulopathy, maintain reasonable glycaemic control

Post-operative care

• Extubation vs ICU ventilation: consider ongoing shock/vasopressors, acidosis, hypothermia, high lactate, poor respiratory mechanics, aspiration, frailty
• Critical care priorities: source control achieved? continue sepsis bundle, vasopressors, fluid balance, renal support if needed, early nutrition plan, DVT prophylaxis when safe
• Analgesia: continue multimodal, epidural if in situ with close haemodynamic monitoring, consider PCA if extubated and stable
• Complications to anticipate: intra-abdominal sepsis/collections, anastomotic leak, ileus, AKI, ARDS, wound complications, delirium

Key differentials and special situations

• Differentials for acute abdomen/free air: perforated ulcer, perforated diverticulitis, ischaemic bowel, pancreatitis (no free air usually), ruptured AAA (mimic), mesenteric ischaemia
• Steroids/immunosuppression: blunted signs, higher infection risk, consider peri-op steroid replacement
• Anticoagulation/coagulopathy: impacts neuraxial options and bleeding risk, correct coagulopathy if possible (vit K, PCC/FFP, platelets) guided by urgency and labs/TEG
• Pregnancy: aspiration risk, aortocaval compression, fetal considerations, left uterine displacement, early obstetric input

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