General Surgery Notes - Acute Abdomen & Emergency Surgery

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1. THE ACUTE ABDOMEN - Overview

Approach (History + Examination)

• Site of pain at onset vs. now (migration is key - e.g., appendicitis migrates from peri-umbilical to RIF)
• Character: colicky (obstruction, ureteric) vs. constant (peritonitis, ischemia)
• Onset: sudden ("like a thunderclap") suggests perforation or ruptured AAA
• Associated symptoms: nausea, vomiting, fever, altered bowel habit, last menstrual period (always in women of reproductive age), urinary symptoms

1. General: Vitals, posture (peritonitis patient lies still; renal colic patient is restless)
2. Inspection: distension, scars, hernias, visible peristalsis
3. Palpation: tenderness, guarding, rigidity, rebound
4. Percussion: resonance (gas) vs dullness (fluid)
5. Auscultation: bowel sounds (high-pitched tinkling = obstruction; absent = paralytic ileus/peritonitis)
6. Always examine hernial orifices and do PR examination

Peritonism Signs

"If inflammation arises under the diaphragm, shoulder tip ('phrenic') pain may be felt. This is referred pain to the C5 dermatome." - Bailey and Love's Surgery, p. 1109

Categories of Peritonitis (Bailey & Love)

• Localised - e.g., appendicitis, diverticulitis (contained)
• Diffuse/generalised - e.g., perforated viscus, faecal peritonitis

• Bacterial (GI perforation, transmural translocation)
• Chemical (bile, barium, gastric acid)
• Ischaemic (strangulated bowel, vascular occlusion)
• Traumatic
• Miscellaneous (familial Mediterranean fever, starch peritonitis)

• GI perforation (ulcer, appendix, diverticulum)
• Transmural translocation without perforation (pancreatitis, ischaemic bowel)
• Exogenous contamination (open trauma, peritoneal dialysis)
• Female genital tract (PID)
• Haematogenous spread (rare)

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2. ACUTE APPENDICITIS

Pathophysiology

Clinical Features

• McBurney's point tenderness - 1/3 of the way from ASIS to umbilicus
• Rovsing's sign - pressure in LIF causes pain in RIF (cross-referred pain)
• Psoas sign - pain on extension of right hip (retrocaecal appendix)
• Obturator sign - pain on internal rotation of flexed right hip (pelvic appendix)
• Cutaneous hyperaesthesia at T10-T12 dermatomes

• Pregnancy: most common surgical emergency; appendix may be displaced upward after 3rd month (though in <25% of cases even in 3rd trimester); peritoneal signs may be diminished. Fetal mortality rises with perforation.
• Elderly: atypical presentation, higher perforation rate
• Children: perforation rate higher due to thin-walled appendix and delayed diagnosis

Investigations

• WBC raised (>10,000/mm³) - earliest marker; but normal WBC does not exclude appendicitis
• CRP >10 mg/L (useful especially in children <6 years)
• WBC + CRP combined sensitivity up to 98%; normal values of both make appendicitis unlikely in low pre-test probability
• Urinalysis: sterile pyuria or microscopic haematuria can occur in appendicitis (don't be misled)
• Urine pregnancy test in all women of reproductive age (rule out ectopic)

• Plain X-ray: not helpful; may show appendicolith (up to 50% in children)
• Ultrasound (US): first-line in children and pregnant women (graded compression technique - non-compressible appendix >6mm diameter)
• CT abdomen/pelvis: most accurate in adults (sensitivity ~94%, specificity ~95%); identifies perforation, abscess, alternate diagnoses
• MRI: preferred in pregnant women when US is inconclusive (avoids radiation)

Scoring Systems (MBBS Exam Favourite)

• Score 1-4: Low risk (observation)
• Score 5-6: Possible appendicitis (imaging/observation)
• Score 7-9: Probable appendicitis (surgical referral)

Note: Modified Alvarado has only 72% sensitivity; clinical judgment by an experienced surgeon remains more accurate. - Tintinalli's Emergency Medicine

Management

• Interval appendicectomy after abscess/phlegmon drainage (controversial)
• Antibiotics alone for uncomplicated appendicitis (growing evidence, but surgery remains standard in most centres)

• Appendicectomy - laparoscopic (preferred) or open (grid-iron/Lanz incision)
• Laparoscopic: better visualisation, fewer wound infections, faster recovery
• Open: grid-iron incision (oblique at McBurney's point); Lanz (transverse, better cosmesis)
• Drains used if perforation with soiling

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3. INTESTINAL OBSTRUCTION

Classification

• Intraluminal: gallstone ileus, meconium, foreign body, bezoar
• Intramural: tumour, Crohn's stricture, intussusception
• Extramural: adhesions (most common), hernias (2nd most common), volvulus, external compression

"It is essential that the hernial orifices should be carefully examined as incarceration in a hernia is one of the commonest causes of obstruction." - Pye's Surgical Handicraft, p. 9038

Small vs Large Bowel Obstruction

Strangulation - RED FLAGS

• Continuous pain (not just colicky)
• Localised tenderness
• Pyrexia
• Tachycardia
• Signs of peritonism
• Rapid deterioration

Investigations

• Erect AXR: multiple air-fluid levels
• Supine AXR: dilated bowel loops; valvulae conniventes (SBO) vs haustra (LBO); pneumoperitoneum (perforation)
• CT scan: investigation of choice; identifies level, cause, strangulation, perforation
• Bloods: FBC, U&E (dehydration), LFT, amylase, lactate (ischaemia), group & save

Management

• IV fluid resuscitation (crystalloid)
• NG tube (nasogastric decompression)
• Urinary catheter (monitor output)
• Analgesia (does NOT mask signs)
• Correct electrolyte imbalances (hyponatraemia, hypokalaemia)

• Strangulation
• Complete obstruction
• Failed conservative management
• LBO with caecal dilatation >9 cm (risk of perforation)

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4. PERFORATED PEPTIC ULCER

Overview

Clinical Features

• Sudden, severe epigastric pain (knife-like) - classically described as "like being shot"
• Pain spreads to whole abdomen rapidly
• Board-like rigidity - classic sign
• Patient lies still (any movement worsens peritonism)
• Referred shoulder tip pain (subphrenic gas)
• Tachycardia, hypotension (if late, septic shock)

Investigations

• Erect CXR: free gas under diaphragm (pneumoperitoneum) - present in ~70-80%
• CT abdomen: more sensitive for free gas; also identifies site of perforation, extent of peritoneal soiling
• Bloods: FBC, U&E, LFT, amylase (raised but usually <3x normal - distinguishes from pancreatitis), coagulation, group & save

Management

• Only if: haemodynamically stable, perforation radiologically sealed, no peritonitis
• Strict monitoring; if worsening → immediate surgery

"Surgery is almost always indicated for ulcer perforation, although occasionally nonsurgical treatment can be used in the stable patient without peritonitis in whom radiologic studies document a sealed perforation." - Schwartz's Surgery 11th Ed

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5. ACUTE MESENTERIC ISCHAEMIA (AMI)

Causes

Clinical Features

• Classic triad: severe central abdominal pain out of proportion to examination findings (early), vomiting, diarrhoea (may be bloody)
• Early: soft abdomen despite severe pain (visceral pain phase)
• Late: peritonism, rigidity, septic shock (transmural infarction + perforation)
• Risk factors: AF, recent MI, atherosclerosis, hypercoagulable state

Investigations

• CT angiography: investigation of choice - shows occlusion, bowel wall thickening, pneumatosis intestinalis (gas in bowel wall), portal venous gas (late ominous sign)
• Bloods: leukocytosis, raised lactate, metabolic acidosis (late)
• Plain AXR: often normal early; "thumb-printing" (mucosal oedema) late

Management

• Resuscitation + anticoagulation (heparin)
• CT angiography to confirm and plan
• Embolectomy / thrombolysis (endovascular or open)
• Laparotomy: bowel resection if necrotic; "second look" laparotomy at 24-48 hours to assess bowel viability
• Antibiotics (broad spectrum, including anaerobic cover)

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6. ACUTE PANCREATITIS (Emergency Context)

Aetiology - "GET SMASHED"

Severity Scoring - Revised Atlanta / Glasgow Criteria (MBBS Favourite)

• PaO₂ < 8 kPa
• Age > 55
• Neutrophils (WBC) > 15 × 10⁹/L
• Calcium < 2 mmol/L
• Raise in urea > 16 mmol/L
• Enzymes: LDH > 600 IU/L; AST > 200 IU/L
• Albumin < 32 g/L
• Sugar (glucose) > 10 mmol/L (Mnemonic: PANCREAS)

Management

• No oral intake (keep nil by mouth if severe/vomiting)
• Aggressive IV fluid resuscitation (Hartmann's/Ringer's lactate preferred over normal saline)
• Analgesia (IV opioids)
• Urinary catheter + fluid balance
• Blood sugar monitoring + insulin sliding scale
• ERCP within 24-72h if gallstone pancreatitis with cholangitis / biliary obstruction
• Antibiotics: not routine (no benefit in sterile necrosis); use only if infected necrosis suspected
• Surgery: step-up approach for infected necrotising pancreatitis (percutaneous drain → minimally invasive necrosectomy → open)

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7. CAUSES OF ACUTE ABDOMEN BY QUADRANT (Quick Reference)

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8. EMERGENCY LAPAROTOMY - GENERAL PRINCIPLES

• Peritonitis (generalised)
• Perforated viscus
• Strangulated bowel
• Unstable haemorrhage (e.g. ruptured AAA)
• Failed conservative management

• Resuscitate first (but do not delay surgery if unstable due to intra-abdominal bleeding)
• IV antibiotics (broad spectrum - cover gram-negative aerobes + anaerobes)
• Urinary catheter, NG tube
• Cross-match blood
• Consent
• Anaesthetic assessment

1. Control contamination and haemorrhage
2. Temporary abdominal closure
3. ICU resuscitation
4. Definitive repair at 24-48h

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Key Exam Points - Quick Summary

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Basics of Surgery - 2nd Year MBBS Notes

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UNIT 1: WOUND HEALING

Definition

Types of Wound Healing

"Healing by first intention is characterized by closure of a wound within 12-24 hours of its formation. These wounds are clean and well perfused... Wound edges are approximated using sutures, skin glue, steri-strips or other mechanical devices." - Scott-Brown's Otorhinolaryngology

Four Phases of Wound Healing (KEY EXAM TOPIC)

Phase 1: Haemostasis (Immediate - minutes)

• Vascular spasm (immediate response)
• Platelet plug formation: platelets adhere to exposed collagen via von Willebrand factor → platelet activation → aggregation (primary haemostasis)
• Coagulation cascade activated → fibrin clot formation (secondary haemostasis)
• Clot acts as scaffold for subsequent healing

Phase 2: Inflammation (Days 1-4)

• Vasodilation and increased vascular permeability
• Neutrophils arrive first (day 1-2): phagocytose bacteria and debris
• Macrophages arrive day 2-3: debridement + release of growth factors (PDGF, TGF-β, VEGF) - the "master cells" of wound healing
• Signs: rubor (redness), calor (heat), dolor (pain), tumour (swelling), functio laesa (loss of function) - Celsus's pentad
• Lymphocytes arrive later - coordinate immune response

Phase 3: Proliferation (Days 4-21)

• Fibroblasts migrate in (attracted by macrophage-derived growth factors) and synthesise collagen (initially Type III - immature)
• Angiogenesis (new blood vessel formation) - driven by VEGF; gives granulation tissue its red granular appearance
• Epithelialisation - keratinocytes migrate across wound surface
• Wound contraction - myofibroblasts (fibroblasts with smooth muscle features) contract wound edges; major in secondary healing

Phase 4: Remodelling / Maturation (Day 21 - 2 years)

• Type III collagen replaced by stronger Type I collagen
• Collagen fibres reorganise along tension lines
• Vascularity decreases (scar becomes pale)
• Maximum tensile strength: ~80% of original skin (never reaches 100%)
• Scar matures over 12-24 months

Wound Strength Timeline

Factors Affecting Wound Healing

• Infection (most important local factor)
• Blood supply (ischaemia delays healing)
• Foreign body / dead tissue (slows healing)
• Haematoma / seroma (acts as culture medium)
• Wound closure tension
• Radiation damage

• Nutrition: Protein deficiency impairs collagen synthesis; Vitamin C needed for hydroxylation of proline/lysine in collagen; Zinc cofactor for collagen synthesis
• Diabetes mellitus (poor perfusion, neuropathy, impaired neutrophil function)
• Steroids / immunosuppressives (inhibit inflammation and collagen synthesis)
• Anaemia, hypoxia
• Age (decreased healing in elderly)
• Jaundice, uraemia
• Malignancy

Abnormal Wound Healing

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UNIT 2: SHOCK

Definition

"Shock is a systemic state of low tissue perfusion that is inadequate for normal cellular respiration." - Bailey & Love's Surgery, p. 634

Pathophysiology at Cellular Level

• Reduced O₂ delivery → cells switch from aerobic → anaerobic metabolism
• Anaerobic metabolism produces lactic acid → systemic metabolic acidosis
• Na⁺/K⁺ pump failure → lysosomal enzyme release → cell lysis
• Potassium released → hyperkalaemia
• Microvascular injury → capillary leak → tissue oedema → worsens hypoxia

Systemic Compensatory Responses

Classification of Shock (4 Types - CHOD)

1. Hypovolaemic Shock (most common surgical type)

• Loss of circulating volume: haemorrhage, burns, GI losses, third-space losses
• Haemorrhagic shock classes (ATLS):

2. Cardiogenic Shock

• Primary pump failure: MI (most common), arrhythmia, valvular disease, myocarditis, blunt cardiac injury
• Features: low CO, raised JVP, pulmonary oedema
• Treatment: Inotropes (dobutamine), treat cause

3. Obstructive Shock

• Mechanical obstruction to cardiac filling/output
• Causes: Cardiac tamponade, Tension pneumothorax, massive PE, air embolus
• Each causes reduced ventricular filling → low CO
• Treatment: Remove obstruction immediately (needle decompression for tension pneumothorax; pericardiocentesis for tamponade)

4. Distributive Shock

• Maldistribution of blood flow - peripheral vasodilation with low SVR
• Subtypes:
  • Septic shock (most common distributive): endotoxin → cytokine storm → vasodilation + capillary leak + myocardial depression
  • Anaphylactic shock: histamine-mediated vasodilation; treat with IM adrenaline 0.5 mg
  • Neurogenic shock: loss of sympathetic tone (high spinal cord injury)

Summary Table: Cardiovascular Features

Management Principles (Surgical Shock)

1. Airway + O₂ (100% via non-rebreather mask)
2. 2 large-bore IV cannulae (antecubital fossa, 14-16G)
3. Bloods: FBC, U&E, LFT, coagulation, G&S / crossmatch, blood cultures (sepsis), lactate
4. IV fluid resuscitation: crystalloid bolus (500 mL Hartmann's) - reassess after each bolus
5. Urinary catheter - monitor urine output (target >0.5 mL/kg/h)
6. Identify and treat the cause
7. Blood products if haemorrhagic shock (1:1:1 ratio of PRBC : FFP : platelets in massive haemorrhage)
8. Vasopressors (noradrenaline) if distributive shock unresponsive to fluids

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UNIT 3: FLUID THERAPY & ELECTROLYTES

Body Fluid Compartments

Maintenance Fluid Requirements (Adults)

• Water: 25-30 mL/kg/day (~2000 mL/day)
• Sodium: 1 mmol/kg/day (~70 mmol/day)
• Potassium: 1 mmol/kg/day (~70 mmol/day)
• Glucose: ~50-100g/day (prevents protein catabolism)

Types of IV Fluids

Electrolyte Disturbances (Surgical Context)

• Causes: excess hypotonic fluids, SIADH (post-op), GI losses
• Symptoms: confusion, seizures (if severe)
• Treat: fluid restriction; slow correction (max 10 mmol/24h to avoid central pontine myelinolysis)

• Causes: vomiting/NG drainage (with alkalosis), diuretics, diarrhoea
• Risks: cardiac arrhythmias, ileus
• Treat: IV KCl (max 20 mmol/h via central line); oral KCl supplements

• Causes: renal failure, cell lysis, Addison's, massive transfusion
• Risks: cardiac arrest (sine-wave ECG pattern)
• Emergency treatment: IV calcium gluconate (membrane stabilisation) → insulin + dextrose → salbutamol → dialysis

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UNIT 4: SURGICAL INFECTIONS

Classification of Wounds (Surgical)

Surgical Site Infection (SSI)

• Superficial incisional SSI: skin and subcutaneous tissue
• Deep incisional SSI: deep soft tissue (fascia, muscle)
• Organ/space SSI: any part of the anatomy opened during surgery (e.g., anastomotic leak, intraabdominal abscess)

• Patient factors: diabetes, obesity (BMI >35), smoking, malnutrition, immunosuppression, ASA grade
• Operative factors: duration >2 hours, dirty/contaminated wound, inadequate prophylaxis, haematoma, dead space

• Antibiotic prophylaxis: single dose IV antibiotics 30-60 min before incision (e.g., co-amoxiclav or cefazolin); NOT extended beyond 24h
• Hair removal: clippers (not razors) on day of surgery
• Skin preparation: chlorhexidine-alcohol > povidone iodine
• Maintain normothermia and normoglycaemia intra-operatively
• Good surgical technique (minimise dead space, avoid haematoma)

Common Surgical Infections

• Rapidly spreading infection of fascia and subcutaneous fat; surgical emergency
• Type I: polymicrobial (Fournier's gangrene)
• Type II: monomicrobial (Group A Strep)
• Features: severe pain out of proportion to appearance, dusky skin, crepitus (gas-forming organisms), systemic toxicity
• Treatment: URGENT surgical debridement (often multiple washouts) + broad-spectrum antibiotics + ICU

• Clostridium perfringens - gas in tissues, brown exudate, "dishwater" fluid
• Treatment: surgical debridement + penicillin G + hyperbaric oxygen

Tetanus

• Clostridium tetani - exotoxin (tetanospasmin) blocks inhibitory interneurons → spastic paralysis
• Features: trismus (lockjaw), opisthotonus, risus sardonicus
• Prophylaxis: wound toilet + tetanus toxoid (if >5 years since last booster); add tetanus immunoglobulin (TIG) if dirty wound + unimmunised
• Treatment: TIG + metronidazole + benzodiazepines (muscle relaxation) + ICU

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UNIT 5: HAEMOSTASIS & BLOOD TRANSFUSION

Haemostasis - Overview

1. Vascular spasm
2. Platelet adhesion: vWF bridges platelet GPIb receptor to exposed collagen
3. Platelet activation: release of ADP, TXA₂ → more platelet recruitment
4. Platelet aggregation: GPIIb/IIIa receptors bind fibrinogen

• Intrinsic pathway (XII → XI → IX → X): activated by contact with subendothelial collagen; measured by APTT
• Extrinsic pathway (VII + Tissue Factor → X): activated by tissue injury; measured by PT/INR
• Common pathway (X → Xa + Va → Prothrombin → Thrombin → Fibrinogen → Fibrin)

Tests of Coagulation

Anticoagulants in Surgery

Blood Products & Transfusion

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UNIT 6: PRE-OPERATIVE & POST-OPERATIVE CARE

Pre-operative Assessment

• Current illness + planned surgery
• Past medical/surgical history
• Medications (especially anticoagulants, antiplatelets, antihypertensives, steroids, insulin)
• Allergies
• Anaesthetic history (family history of malignant hyperthermia)
• Smoking, alcohol, substance use
• Last oral intake (fasting status: 6h for solids, 2h for clear fluids - "6-4-2 rule")

Pre-operative Preparation

• Fasting: 6h solids, 2h clear fluids
• Stop anticoagulants appropriately (warfarin 5 days; DOACs 24-48h; aspirin continue for most surgery)
• Diabetic management: omit morning oral hypoglycaemics on day of surgery; start insulin sliding scale if prolonged fasting
• Prophylactic LMWH for DVT prevention (start evening before or post-op)
• TED stockings / intermittent pneumatic compression
• Antibiotic prophylaxis: single dose 30-60 min before incision
• Bowel prep (selected colorectal cases only)
• Consent and marking the site (especially for laterality)

Post-operative Monitoring

• Observations every 15-30 min initially: HR, BP, RR, SpO₂, temperature, GCS
• Urine output: target >0.5 mL/kg/h (30 mL/h in 70 kg adult)
• NEWS2 score (National Early Warning Score): triggered escalation for deteriorating patients

Post-operative Complications - Timeline

• Atelectasis (most common, days 1-2): microcollapses → fever, ↓O₂; treat with physiotherapy, incentive spirometry
• Pneumonia: cough, fever, consolidation; treat with antibiotics
• PE (day 5-10 peak): pleuritic chest pain, haemoptysis, tachycardia; CTPA to confirm; treat with anticoagulation

• DVT: calf pain, swelling; duplex USS; treat with LMWH then DOAC for 3 months
• MI: ECG + troponin; highest risk day 1-3 post-op

• Haematoma: collection of blood; usually resolves; aspirate/drain if large
• Seroma: serous fluid collection; common post-mastectomy/hernia; aspirate if symptomatic
• Wound infection (SSI): days 4-7; erythema, pus, fever; open wound + antibiotics

• Retention: common post-pelvic surgery and in elderly men; catheterise
• UTI: very common; MSSU + antibiotics

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UNIT 7: SURGICAL NUTRITION

Importance

Nutritional Assessment

• History: weight loss (>10% in 6 months = significant), reduced intake
• BMI: <18.5 kg/m² = underweight
• MUST score (Malnutrition Universal Screening Tool): BMI + weight loss + acute disease effect → low/medium/high risk
• Serum albumin (<35 g/L = hypoalbuminaemia; marker of chronic malnutrition)
• Serum prealbumin (half-life 2-3 days, better acute marker)

Nutritional Requirements (Surgical Patient)

• Calories: 25-30 kcal/kg/day (higher if sepsis/burns/major trauma: up to 35-40)
• Protein: 1-2 g/kg/day (nitrogen balance)
• Key micronutrients for healing: Vitamin C, Zinc, Vitamin A

Routes of Nutritional Support

• Maintains gut mucosal integrity (prevents bacterial translocation)
• Lower cost
• Lower infection risk (TPN associated with line infections, metabolic complications)
• Preserves gut immune function

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UNIT 8: SURGICAL ONCOLOGY BASICS

Tumour Classification

Staging (TNM System)

• T - Primary tumour (T0-T4)
• N - Regional lymph nodes (N0-N3)
• M - Distant metastasis (M0-M1)

Routes of Tumour Spread

1. Direct / local invasion - into adjacent structures
2. Lymphatic spread - most common route for carcinomas
3. Haematogenous spread - common for sarcomas; via portal vein → liver; systemic veins → lungs
4. Transcoelomic spread - across body cavities (peritoneum, pleura); e.g., gastric cancer → "Sister Mary Joseph nodule" (umbilical), Krukenberg tumour (ovary)
5. Perineural spread - along nerve sheaths (e.g., prostate cancer)
6. Implantation - port site metastasis after laparoscopy, surgical seeding

Tumour Markers (Surgical Context)

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QUICK REVISION TABLE - High Yield Points

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Preoperative Checkups (Pre-operative Assessment)

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What Is a Preoperative Assessment?

• Determine the patient's fitness for surgery and anaesthesia
• Identify and optimise medical comorbidities
• Anticipate complications
• Plan perioperative management
• Obtain informed consent

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1. HISTORY TAKING

A. Present Illness

• Nature of the surgical condition
• Urgency: elective vs. emergency surgery
• Symptoms affecting fitness (dyspnoea, chest pain, bleeding tendency)

B. Past Medical History (PMH)

C. Past Surgical/Anaesthetic History

• Previous surgeries and complications
• Difficult airway history
• Family history of malignant hyperthermia (rare but life-threatening reaction to anaesthetic agents - autosomal dominant)
• Postoperative nausea and vomiting (PONV) history

D. Drug History

E. Allergy History

• Drug allergies (especially latex, antibiotics, anaesthetic agents, iodine/contrast)
• Document type of reaction (rash vs anaphylaxis)

F. Social History

• Smoking: increases respiratory complications; ideally stop 8+ weeks before elective surgery
• Alcohol: increases anaesthetic requirements, hepatic dysfunction, bleeding risk; assess for withdrawal risk
• Recreational drugs (especially cocaine: cardiovascular instability)
• BMI/obesity: risk of difficult airway, respiratory complications, wound infection, DVT
• Home support: important for day-case surgery - responsible adult must accompany patient home

G. Fasting Status ("6-4-2 Rule")

For emergency surgery, always ask "When did you last eat/drink?" - full stomach = aspiration risk → rapid sequence induction (RSI) needed

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2. PHYSICAL EXAMINATION

General

• Weight, height, BMI
• Nutritional status (muscle wasting, pallor)
• Level of consciousness, GCS

Airway Assessment (CRITICAL for anaesthetist)

• Thyromental distance (chin to thyroid notch with neck extended): <6 cm = difficult intubation
• Inter-incisor gap: <3 cm = difficult
• Neck mobility (reduced in cervical spine disease, rheumatoid arthritis)
• Prominent teeth, micrognathia, beard (mask seal), history of trismus

Cardiovascular

• Heart rate, blood pressure (both arms)
• JVP assessment
• Heart sounds (murmurs may indicate valvular disease → echo needed)
• Peripheral oedema
• Peripheral pulses

Respiratory

• Respiratory rate, SpO₂
• Chest expansion
• Auscultation: wheeze (asthma/COPD), crackles (pulmonary oedema, infection)
• Exercise tolerance: "Can you climb a flight of stairs without stopping?" - if yes, suggests adequate cardiorespiratory reserve (>4 METs)

Abdomen

• Relevant to type of surgery planned
• Existing scars (adhesions), hernias, organomegaly, ascites

Other

• Neurological assessment if relevant
• Look for signs of DVT (calf tenderness, swelling)
• Veins (IV access - identify difficult access early)

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3. INVESTIGATIONS

Blood Tests

Cardiac Investigations

• 0 factors: <1% major cardiac event risk
• 1 factor: ~1%
• 2 factors: ~2.4%
• ≥3 factors: ~5.4%

Respiratory Investigations

Other Investigations

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4. RISK STRATIFICATION

ASA Physical Status Classification

Functional Capacity - METs (Metabolic Equivalents)

• 1 MET: Self-care (dressing, eating)
• 4 METs: Climbing one flight of stairs (key threshold)
• >10 METs: Heavy exercise (swimming, vigorous sport)

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5. SPECIFIC OPTIMISATION BEFORE SURGERY

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6. CONSENT

1. Informed - patient must be told: nature of procedure, benefits, risks (common AND serious/rare), alternatives, consequences of doing nothing
2. Voluntary - free from coercion
3. Capacity - patient must understand, retain, weigh, and communicate the decision

• Form 1: Adult with capacity (most common)
• Form 2: Parental consent for child
• Form 3: Unable to consent (e.g., unconscious emergency)

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7. DVT PROPHYLAXIS ASSESSMENT

• Age >60, obesity, malignancy, previous DVT/PE, thrombophilia, prolonged surgery, pelvic surgery, prolonged immobility, OCP/HRT

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8. PREOPERATIVE CHECKLIST (DAY OF SURGERY)

• Patient identity confirmed (name, DOB, hospital number)
• Consent form signed and present
• Surgical site marked (if applicable - especially laterality: right vs left)
• Allergies documented and wristband applied
• Fasting confirmed (6h solids, 2h fluids)
• Pre-medication given if prescribed (anxiolytic, antacid)
• Antibiotic prophylaxis prescribed (given 30-60 min before incision)
• DVT prophylaxis in place (stockings on; LMWH given)
• Relevant investigations reviewed (blood results, ECG, imaging)
• IV access established
• Blood products available if needed (crossmatch confirmed)
• Implants/prosthetics/devices noted (e.g., pacemaker, hip replacement)
• WHO Surgical Safety Checklist completed (Sign In → Time Out → Sign Out)

WHO Surgical Safety Checklist (3 Stages)

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Quick Summary - What Gets Checked Pre-operatively

HISTORY          → PMH, drugs, allergies, anaesthetic history, social history, fasting
EXAMINATION      → Airway, CVS, respiratory, weight/BMI, relevant system
INVESTIGATIONS   → Bloods (FBC, U&E, coag, G&S), ECG, CXR, spirometry
RISK SCORING     → ASA grade, cardiac risk index, METs, DVT risk
OPTIMISATION     → Control BP/DM, treat anaemia, stop/adjust drugs
CONSENT          → Informed, voluntary, capacity
PROPHYLAXIS      → Antibiotics, DVT (LMWH + stockings)
DAY OF SURGERY   → WHO checklist, site marking, confirm fasting, IV access

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Preoperative Checkup & Preparation

For Major Abdominal Surgery Under General Anaesthesia in an Obese + Asthmatic Patient

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WHY THIS PATIENT IS HIGH RISK

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STEP 1: HISTORY

A. Standard Surgical History

• Nature of abdominal condition and indication for surgery
• Urgency: elective vs. emergency

B. Obesity-Specific History

• BMI calculation (weight in kg / height² in m²)
  • Overweight: 25-29.9
  • Obese: 30-39.9
  • Morbidly obese: ≥40
• Duration and degree of obesity
• Obstructive Sleep Apnoea (OSA) - screened with STOP-BANG questionnaire:
  • Snoring, Tiredness, Observed apnoea, blood Pressure, BMI >35, Age >50, Neck >40cm, male Gender
  • Score ≥3 = high risk for OSA → sleep study before elective surgery
• Symptoms of GORD / reflux (obese patients: increased intra-abdominal pressure → higher aspiration risk)
• Exercise tolerance (assess functional capacity in METs)
• Associated comorbidities in obesity: hypertension, type 2 diabetes, IHD, dyslipidaemia, fatty liver (NAFLD/NASH), hypothyroidism

C. Asthma-Specific History

• Duration and severity of asthma (mild intermittent → severe persistent)
• Current control: well-controlled vs. partially controlled vs. uncontrolled
• Current medications: SABA (salbutamol), LABA, inhaled corticosteroids (ICS), oral steroids, theophylline
• Frequency of SABA use (>2x/week = poorly controlled)
• Recent exacerbations or hospitalisations / ICU admissions
• Triggers: cold air, exercise, NSAIDs, aspirin, dust, infections - surgical environment can trigger
• Previous anaesthesia: any history of intraoperative bronchospasm?
• Oral steroid use within the last 6 months → adrenal suppression → need for steroid stress cover

D. Medication History and Adjustments

E. Allergies

• Drug allergies (latex allergy common in asthmatics; penicillin allergy)
• Aspirin/NSAID sensitivity (aspirin-exacerbated respiratory disease - AERD)

F. Social History

• Smoking (worsens both asthma and post-op respiratory complications)
• Alcohol history
• Physical activity level / exercise tolerance

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STEP 2: PHYSICAL EXAMINATION

General

• Weight, height, BMI
• Distribution of fat (central/abdominal obesity is higher risk)
• Neck circumference (>40 cm = OSA risk and difficult intubation)

AIRWAY ASSESSMENT (Critical in obese patients)

"The incidence of difficult intubation in obese patients was three times the incidence compared to the non-obese population." - Miller's Anaesthesia 10th Ed

• Head elevated 30° with ear aligned with sternum horizontally (not flat supine)
• Improves laryngoscopic view significantly
• Can use stacked blankets or commercial ramp device

"Obese patients should be readily intubated by direct laryngoscopy if placed carefully in ramped position... Video laryngoscopy provides better glottic view and decreased intubation time in obese patients." - Miller's Anaesthesia 10th Ed

Respiratory Examination

• Respiratory rate, SpO₂ on room air
• Chest shape (barrel chest in longstanding asthma)
• Auscultation: wheeze, prolonged expiratory phase, air entry - document baseline
• Evidence of active wheeze or current exacerbation → postpone elective surgery until controlled

Cardiovascular Examination

• BP (both arms - hypertension very common in obese)
• Heart rate (tachycardia in poorly controlled asthma from SABA use)
• JVP, peripheral oedema
• Auscultate for murmurs (LVH from obesity hypertension)

Abdominal Examination

• Assess for hepatomegaly (NAFLD), ascites, abdominal mass
• Identify previous scars (adhesions risk)
• Document abdominal girth

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STEP 3: INVESTIGATIONS

Routine Bloods (ALL patients, major surgery)

Respiratory Investigations

• FEV₁ ideally >80% predicted (well-controlled asthma)
• If FEV₁ <80%: optimise bronchodilator + steroid therapy; repeat before proceeding

Cardiac Investigations

Sleep Studies

• Polysomnography if STOP-BANG score ≥3 or clinical suspicion of OSA
• If confirmed OSA: CPAP pre-op to reverse upper airway oedema; continue post-op
• If untreated OSA present → significantly increased risk of post-op hypoxaemia, arrhythmia, respiratory arrest

Additional Investigations for Obese Patient

• Ultrasound abdomen: NAFLD, gallstones (obese patients have 3x cholesterol gallstone risk)
• Fasting insulin level / HOMA-IR if insulin resistance suspected

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STEP 4: RISK STRATIFICATION

ASA Classification (likely Grade in this patient)

Respiratory Risk

• Low SpO₂ (<95%), upper abdominal surgery, >2h operative time, emergency surgery, age >50, COPD/asthma → each adds risk

• Bronchospasm
• Atelectasis (very common - obesity + splinted diaphragm post-laparotomy)
• Pneumonia
• Hypoxaemia requiring re-intubation
• Respiratory failure

Cardiac Risk

• Calculate Revised Cardiac Risk Index (RCRI)
• Obesity itself (metabolic syndrome, hypertension) raises cardiac risk
• Major abdominal surgery = high-risk surgery (adds 1 point to RCRI)

DVT/PE Risk

• Obesity alone = high VTE risk (relative risk x2-3)
• Major abdominal surgery = additional VTE risk
• → Extended prophylaxis (28 days post-op LMWH) warranted

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STEP 5: OPTIMISATION BEFORE SURGERY

A. Asthma Optimisation (MOST IMPORTANT RESPIRATORY STEP)

"Preoperative treatment with combined corticosteroids and an inhaled β₂-adrenergic agonist for a 5-day period may decrease the risk of postoperative bronchospasm in patients with asthma." - Berek & Novak's Gynaecology

1. Review and document current asthma control using GINA criteria
2. Optimise ICS dose: increase to maximum tolerated dose 1-2 weeks before surgery
3. Add LABA if not already prescribed (LABA + ICS combination)
4. Short course of oral prednisolone (40 mg/day for 5 days) if:
   • Moderate-severe or poorly controlled asthma
   • Any active wheeze at assessment
   • Repeat after course → re-assess FEV₁ before proceeding
5. Give SABA (salbutamol 2 puffs) 2 hours before induction on day of surgery
6. Postpone elective surgery if:
   • Active wheeze / acute exacerbation
   • Peak flow <75% predicted
   • Recent URTI (airway hyperresponsiveness peaks 6 weeks after URTI)

• Give hydrocortisone 25-50 mg IV at induction
• Continue 25 mg IV 8-hourly for 24h post-op
• Then return to usual dose
• (Prevents perioperative adrenal crisis from HPA axis suppression)

B. Obesity Optimisation

C. Stop Smoking

• Stop at least 8 weeks before elective surgery for meaningful reduction in pulmonary complications
• Even stopping 1-2 weeks before reduces sputum volume and improves mucociliary clearance
• Nicotine replacement therapy can be prescribed

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STEP 6: ANAESTHETIC CONSIDERATIONS (Key Points for Communication with Anaesthetist)

Airway Plan

• Pre-oxygenate for longer (obese patients desaturate rapidly - reduced FRC)
• Position in ramped position (not flat supine) - ear-to-sternal notch alignment
• Video laryngoscopy preferred as first choice (better view, less trauma)
• Difficult airway trolley immediately available (LMA rescue, fibreoptic bronchoscope)
• Consider awake fibreoptic intubation if Mallampati IV + other difficult airway predictors

Aspiration Risk

• Obese patients have higher gastric volumes, lower gastric pH, increased reflux
• Give H₂ blocker (ranitidine) or PPI + sodium citrate (antacid) pre-op
• Consider Rapid Sequence Induction (RSI) with cricoid pressure

Bronchospasm Prevention

• Avoid: intubation under light anaesthesia; NSAIDs (aspirin-sensitive asthmatic); histamine-releasing drugs (morphine, atracurium); endotracheal tube stimulation while not deep enough
• Use: propofol induction (broncho-protective vs. thiopentone); ketamine (bronchodilator); sevoflurane or desflurane (least irritant volatile agents); IV magnesium sulphate (if refractory bronchospasm)
• Have IV salbutamol and IV hydrocortisone drawn up in theatre

Ventilation Strategy (Intraoperative)

• Use lung-protective ventilation: tidal volume 6-8 mL/kg ideal body weight (IBW), not total body weight
• Apply PEEP 5-10 cmH₂O (prevents atelectasis in obese)
• Reverse Trendelenburg position improves diaphragmatic excursion and FRC
• Aim for SpO₂ >95% throughout

Drug Dosing in Obese Patients

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STEP 7: PREOPERATIVE PREPARATION (Day Before + Day Of Surgery)

Night Before Surgery

• NBM from midnight for solids (6h rule); clear fluids allowed up to 2h before
• Carbohydrate loading drink (200 mL at midnight; 200 mL at 6 AM) if not diabetic and elective surgery - reduces insulin resistance and post-op nausea (ERAS protocol)
• Continue CPAP if OSA patient
• Continue regular asthma inhalers (ICS, LABA) as normal
• Written consent obtained with patient fully informed of specific risks

Day of Surgery

• SABA inhaler (salbutamol 2 puffs) given 2h before transfer to theatre
• IV access established (may be difficult in obese - use ultrasound guidance if needed)
• IV fluids as prescribed
• Antibiotic prophylaxis: single dose IV 30-60 min before incision
  • Standard: co-amoxiclav 1.2g IV or cefuroxime 1.5g IV
  • Higher dose may be needed in obese (e.g., cefazolin 3g if BMI >40)
  • If penicillin-allergic asthmatic: use ciprofloxacin + metronidazole (avoid cephalosporins if true allergy)
• DVT prophylaxis: TED stockings + intermittent pneumatic compression (IPC) devices
  • LMWH: give evening before OR 12h post-op (depending on surgical bleeding risk)
  • Fondaparinux or UFH if LMWH contraindicated
• Steroid stress cover (hydrocortisone 25-50 mg IV) at induction if on steroids
• Antacid prophylaxis: PPI or H₂ blocker + sodium citrate 30 mL oral
• Anti-emetics prescribed (PONV very common post abdominal surgery)
• Pre-medication: short-acting anxiolytic if needed (avoid respiratory depressants)
• Surgical site marked by operating surgeon
• WHO Safety Checklist completed

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STEP 8: POST-OPERATIVE PLAN (Must be discussed pre-operatively)

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SUMMARY CHECKLIST - ONE PAGE OVERVIEW

HISTORY
  ✓ Asthma: severity, control, medications, triggers, previous bronchospasm under GA
  ✓ Obesity: BMI, OSA (STOP-BANG), GORD, DM, HTN, exercise tolerance
  ✓ Drugs: steroids, inhalers, antihypertensives, metformin, anticoagulants
  ✓ Allergies: aspirin/NSAIDs (AERD), latex, antibiotics

EXAMINATION
  ✓ BMI, neck circumference, weight distribution
  ✓ AIRWAY: Mallampati, thyromental distance, mouth opening, neck mobility
  ✓ Chest: wheeze, SpO₂, air entry
  ✓ CVS: BP, JVP, oedema
  ✓ Abdomen: NAFLD, varices

INVESTIGATIONS
  ✓ Bloods: FBC, U&E, LFT, glucose/HbA1c, coag, TFTs, albumin, G&S
  ✓ Spirometry: FEV₁, FVC, peak flow
  ✓ CXR, ECG
  ✓ ABG if SpO₂ <94% or severe asthma
  ✓ Sleep study if STOP-BANG ≥3
  ✓ Echo if suspected cardiac disease

OPTIMISATION
  ✓ Asthma: 5-day pre-op ICS + SABA course; oral prednisolone if poorly controlled
  ✓ SABA 2 puffs 2h before induction
  ✓ CPAP for OSA
  ✓ PPI for GORD
  ✓ DM: HbA1c <8.5%, sliding scale
  ✓ BP: <160/100
  ✓ Stop smoking ≥8 weeks pre-op
  ✓ Pre-op physiotherapy / IMT

DAY OF SURGERY
  ✓ Fasting: 6h solids, 2h fluids
  ✓ Continue inhalers; steroid stress cover if indicated
  ✓ Antibiotics: higher dose for obese 30-60 min before incision
  ✓ DVT: TED stockings + IPC + LMWH
  ✓ Antacid + anti-emetic
  ✓ WHO checklist, site marking, consent

POST-OP
  ✓ HDU monitoring
  ✓ Resume CPAP; restart inhalers
  ✓ Multimodal analgesia (avoid NSAIDs if aspirin-sensitive)
  ✓ Early physio + mobilisation
  ✓ LMWH 28 days

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Preoperative Checkup & Preparation

Major Abdominal Surgery Under GA — Obese + Asthmatic Patient

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WHY THIS PATIENT IS HIGH RISK

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1. HISTORY

Asthma-Specific

• Severity and current control (GINA criteria)
• Medications: SABA, ICS, LABA, oral steroids, theophylline
• SABA use >2×/week = poorly controlled
• History of intraoperative bronchospasm under previous GA
• Oral steroid use within last 6 months → adrenal suppression → stress cover needed
• Triggers: NSAIDs/aspirin (Samter's triad), cold air, infections
• Recent URTI (airway hyperresponsiveness persists 6 weeks after)

Obesity-Specific

• BMI (obese ≥30; morbidly obese ≥40)
• STOP-BANG score for OSA (≥3 = high risk): Snoring, Tiredness, Observed apnoea, blood Pressure, BMI >35, Age >50, Neck >40 cm, male Gender
• GORD/reflux symptoms (↑ aspiration risk)
• Associated: hypertension, type 2 DM, dyslipidaemia, NAFLD, hypothyroidism

Drugs to Adjust

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2. EXAMINATION

Airway (Critical - 3× harder to intubate in obese)

Respiratory

• SpO₂ on room air; auscultate for wheeze, reduced air entry
• Active wheeze = postpone elective surgery

Cardiovascular

• BP both arms (hypertension common); JVP, oedema; auscultate for murmur (LVH)

Abdomen

• Hepatomegaly (NAFLD), previous scars (adhesions)

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3. INVESTIGATIONS

Blood Tests

Respiratory

Cardiac

Sleep Study (Polysomnography)

• If STOP-BANG ≥3 → confirm OSA → start CPAP pre-op

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4. RISK STRATIFICATION

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5. OPTIMISATION

Asthma Optimisation

1. Maximise ICS for 1-2 weeks pre-op
2. 5-day pre-op course: ICS + SABA combination → reduces bronchospasm risk
3. Oral prednisolone 40 mg/day × 5 days if poorly controlled / active wheeze
4. Re-check FEV₁ after course before proceeding
5. Postpone if: active wheeze, peak flow <75%, recent URTI within 6 weeks

• Hydrocortisone 25-50 mg IV at induction
• Then 25 mg IV 8-hourly × 24h → taper to usual dose

Obesity Optimisation

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6. DAY OF SURGERY PREPARATION

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7. ANAESTHETIC CONSIDERATIONS (Communicate to Anaesthetist)

Airway Management

• Extended pre-oxygenation (obese desaturate rapidly - reduced FRC)
• Ramped position (ear-to-sternal notch)
• Video laryngoscopy first choice
• RSI with cricoid pressure (aspiration risk)
• Awake fibreoptic intubation if Mallampati IV + multiple difficult airway predictors

Bronchospasm Prevention

• Use propofol induction (broncho-protective)
• Avoid NSAIDs, histamine-releasing drugs (morphine, atracurium)
• Do not intubate under light anaesthesia
• Have IV salbutamol + IV hydrocortisone drawn up in theatre

Ventilation

• Tidal volume 6-8 mL/kg ideal body weight (not total)
• PEEP 5-10 cmH₂O (prevents atelectasis)
• Reverse Trendelenburg position improves diaphragm excursion

Drug Dosing

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8. POST-OPERATIVE PLAN

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QUICK SUMMARY

HISTORY    → Asthma control, OSA (STOP-BANG), GORD, DM, HTN, drugs, allergies
EXAM       → Airway (Mallampati, neck, thyromental), SpO₂, wheeze, BP, BMI
BLOODS     → FBC, U&E, LFT, glucose/HbA1c, TFTs, coag, albumin, G&S
RESP       → Spirometry (FEV₁>80%), CXR, ABG if severe, sleep study if OSA
CARDIAC    → ECG, echo if indicated, CPET if poor exercise tolerance
OPTIMISE   → 5-day ICS+SABA, prednisolone if poor control, CPAP, PPI,
              BP/DM control, stop smoking, pre-op physiotherapy
DAY OF OP  → Salbutamol 2 puffs 2h before, steroid cover, antacid,
              higher-dose antibiotics, TED+IPC+LMWH, WHO checklist
POST-OP    → HDU, CPAP, inhalers, multimodal analgesia, early physio + mobilise

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Types & Incisions of Abdominal Surgery

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PART 1: ABDOMINAL WALL ANATOMY (Foundation)

Layers of the Anterior Abdominal Wall (Superficial → Deep)

1. Skin
2. Subcutaneous fat (Camper's fascia - superficial fatty layer)
3. Scarpa's fascia (deep membranous layer - important in wound closure)
4. External oblique muscle/aponeurosis - fibres run downward and medially ("hands in pockets")
5. Internal oblique muscle - fibres run upward and medially (opposite to external)
6. Transversus abdominis muscle - fibres run horizontally
7. Transversalis fascia
8. Extraperitoneal fat
9. Peritoneum (parietal)

Rectus Sheath

• The aponeuroses of the three flat muscles (external oblique, internal oblique, transversus abdominis) envelop the rectus abdominis muscle to form the rectus sheath
• Above arcuate line (~midway between umbilicus and pubis): posterior sheath present (all three aponeuroses share anteriorly and posteriorly)
• Below arcuate line: all aponeuroses pass anterior to rectus → no posterior sheath below this line → only transversalis fascia + peritoneum posteriorly

Linea Alba

• Fibrous band running from xiphisternum to pubic symphysis
• Formed by fusion of aponeuroses of the three flat muscles in the midline
• Avascular - hence midline incisions bleed minimally and heal well
• Widens above the umbilicus (4-5 mm) - risk of epigastric hernia

Blood Supply (Clinically Important)

• Superior epigastric artery (from internal thoracic artery) - runs behind rectus muscle
• Inferior epigastric artery (from external iliac artery) - runs behind rectus muscle
• Both anastomose within the rectus muscle
• Danger: paramedian incisions and laparoscopic ports placed lateral to midline can injure the inferior epigastric vessels → haematoma

Nerve Supply (Clinically Important)

• Thoracoabdominal nerves T7-T11 + subcostal nerve T12 + iliohypogastric and ilioinguinal nerves L1
• Run between internal oblique and transversus abdominis
• Danger: lateral incisions and paramedian incisions can denervate the rectus → weakness, hernia

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PART 2: GENERAL PRINCIPLES OF INCISIONS

Goals of a Good Surgical Incision

"The goal of an efficacious incision is to provide adequate exposure to perform the procedure with minimal perturbation of the abdominal wall function." - Schwartz's Surgery 11th Ed

• Adequate exposure of the operative target
• Extensible (can be enlarged if needed)
• Minimal injury to muscles, nerves, blood vessels
• Good cosmetic result
• Allows secure closure without tension
• Low risk of hernia formation

Two Broad Categories of Incisions

"There does not appear to be differences in early or late postoperative complications or recovery time between these two types of incisions. However, transverse incisions may be associated with lower incisional hernia rates but higher rates of wound infections." - Schwartz's Surgery 11th Ed

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PART 3: SPECIFIC INCISIONS - DETAILED

A. MIDLINE INCISION (Most Common Surgical Incision)

• Upper midline: xiphisternum to umbilicus (deviating around umbilicus)
• Lower midline: umbilicus to pubis
• Full midline: xiphisternum to pubis (emergency laparotomy)

• Emergency laparotomy (perforated viscus, intestinal obstruction, trauma)
• Exploratory laparotomy
• Aortic surgery
• Colonic surgery (right/left hemicolectomy, sigmoid colectomy)
• Small bowel surgery
• Gynaecological procedures (hysterectomy, ovarian surgery)
• Liver surgery

• Fastest to open and close
• Avascular (linea alba)
• No muscle or nerve damage
• Easily extensible (full xiphi-pubic if needed)
• Minimal blood loss
• Can be reopened for re-laparotomy

• Higher risk of incisional hernia vs. transverse (debated)
• Poor cosmesis
• Post-op pain limits respiration (especially upper midline)

• Classical: sutures 1 cm from edge, 1 cm apart
• Modern evidence: shorter stitch width (5-8 mm) reduces incisional hernia rates

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B. PARAMEDIAN INCISION

• Right paramedian or left paramedian

• Limits access to contralateral side
• Risk of injury to inferior epigastric vessels
• Risk of rectus denervation if too lateral
• More complex closure (two layers)

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C. KOCHER INCISION (Right/Left Subcostal)

• Right Kocher: right subcostal
• Left Kocher: left subcostal
• Bilateral Kocher (Chevron/Rooftop): both sides joined - classic "inverted V"
• Mercedes-Benz extension: midline vertical added to bilateral Kocher

• Right Kocher: liver, gallbladder, biliary tree, right adrenal
• Left Kocher: spleen, left adrenal, tail of pancreas, stomach
• Bilateral (Chevron): liver transplant, oesophagogastric surgery, major hepatic resections, Whipple's procedure (pancreaticoduodenectomy), total gastrectomy

• Excellent exposure to upper abdominal organs
• Follows Langer's lines (better healing, cosmesis)

• Cuts through rectus muscle → more post-op pain
• Risk of injury to intercostal nerves → rectus weakness
• More complex closure (two layers)
• Not easily extensible beyond the bilateral form

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D. GRID-IRON INCISION (McBurney's Incision)

• External oblique: split along its fibres (downward and medially)
• Internal oblique: split along its fibres (upward and medially) - perpendicular to external
• Transversus abdominis: split along its fibres (horizontally)

• Muscle fibres split (not cut) → better healing, less herniation
• Low post-op pain
• Good cosmesis

• Very limited access - cannot extend well
• Cannot access other areas if diagnosis is wrong (then use midline)

E. LANZ INCISION

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F. PFANNENSTIEL INCISION

1. Transverse skin incision (curved, convex upward)
2. Anterior rectus sheath incised transversely
3. Sheath dissected off rectus muscles (superiorly and inferiorly)
4. Rectus muscles separated in the midline
5. Transversalis fascia and peritoneum opened longitudinally

• Hysterectomy, Caesarean section, myomectomy
• Pelvic lymph node dissection
• Bladder surgery (cystectomy)
• Pelvic colorectal surgery

• Excellent cosmesis (scar hidden in pubic hair line)
• Strong wound (three-layer closure)
• Low hernia rate

• Limited access to upper abdomen
• Risk of injury to ilioinguinal nerve (lateral extension)
• If infected: mesh often required for closure

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G. RUTHERFORD-MORRISON INCISION

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H. ROOFTOP / CHEVRON INCISION

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I. THORACOABDOMINAL INCISION

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PART 4: SUMMARY TABLE - ALL INCISIONS

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PART 5: TYPES OF ABDOMINAL SURGERY

By Approach

1. Open Surgery (Laparotomy)

• Direct access via one of the incisions above
• Better tactile feedback, no equipment limitations
• Indicated for: emergency surgery, complex procedures, failed laparoscopy, gross contamination, massive haemorrhage

2. Laparoscopic Surgery (Minimally Invasive)

• Hasson (open) technique: direct visualization and systematic opening of each fascial layer; then blunt trocar placed - safer, preferred if previous abdominal surgery (adhesions)
• Veress needle (closed) technique: blind needle insertion (usually at umbilicus); CO₂ gas insufflated; confirmed by saline drop test or pressure reading; then trocars placed
• Optimal intra-abdominal pressure: 10-15 mmHg (>25 mmHg = risk of gas embolism, acidosis, reduced venous return)

• Camera port (usually umbilical - 10-12mm)
• Working ports (5-12mm at various positions depending on the operation)
• Key: maintain working angles and avoid clashing of instruments

• Smaller incisions → less post-op pain
• Earlier return to normal activity
• Reduced wound infections
• Shorter hospital stay
• Better cosmesis
• Reduced adhesion formation
• Reduced post-op ileus

• Loss of tactile (haptic) feedback
• Longer operating time (learning curve)
• Cannot be used in haemodynamic instability
• CO₂ pneumoperitoneum: impairs venous return, increases VTE risk, absorbed → hypercarbia
• Equipment-dependent; expensive

• Haemodynamic instability
• Massive abdominal distension
• Unable to tolerate pneumoperitoneum (severe cardiac/respiratory disease)
• Severe adhesions (relative)

3. Hand-Assisted Laparoscopic Surgery (HALS)

• A hand port allows the surgeon to insert a hand while maintaining pneumoperitoneum
• Benefits: tactile feedback, easier haemostasis, specimen removal - used in complex colorectal or nephrectomy

4. Robotic Surgery (Robot-Assisted)

• Robotic arms controlled by surgeon at console
• 3D vision, wristed instruments (greater range of motion than standard laparoscopy)
• Used in: prostatectomy, rectal surgery, oesophageal surgery, bariatric surgery
• Disadvantages: high cost, no haptic feedback, longer set-up time

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By Organ / Operation Type

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PART 6: CLOSURE OF ABDOMINAL INCISIONS

Layers to Close

• Peritoneum: often NOT closed separately now (evidence shows no benefit; can cause adhesions)
• Fascial layer (linea alba / rectus sheath): most important layer - bears all tension
• Subcutaneous fat: close if dead space is significant
• Skin: sutures, staples, or clips

Mass Closure vs. Layered Closure

• Mass closure: all layers of the abdominal wall included in a single suture bite
• Layered closure: each layer closed separately
• Evidence favours mass closure for midline laparotomy - comparable or superior burst abdomen and hernia rates

Suture Material for Fascial Closure

• Continuous (loop) PDS (polydioxanone) or nylon (prolene): most commonly used
• PDS is absorbable (slowly, over 6 months) - preferred for elective
• Nylon is non-absorbable - preferred for contaminated/emergency cases
• Suture-to-wound length ratio should be ≥4:1 (take enough tissue to reduce tension)

Complications of Abdominal Incisions

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QUICK REVISION TABLE

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Preoperative Checkup & Preparation

Major Abdominal Surgery Under GA — Obese Patient

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WHY OBESITY INCREASES SURGICAL RISK

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1. HISTORY

Obesity-Specific

• BMI (Obese ≥30; Morbidly obese ≥40; Super-obese ≥50)
• OSA screening - STOP-BANG score (≥3 = high risk):

• GORD / reflux symptoms (↑ aspiration risk under GA)
• Exercise tolerance - "Can you climb one flight of stairs?" (= 4 METs threshold)
• Comorbidities: type 2 DM, hypertension, IHD, dyslipidaemia, hypothyroidism, NAFLD

Drug History & Adjustments

Allergies

• Latex allergy (more common in obese/repeated surgery patients)
• Drug allergies (antibiotics, anaesthetic agents)

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2. PHYSICAL EXAMINATION

General

• Accurate weight, height, BMI
• Fat distribution: central/abdominal vs. peripheral
• Neck circumference (>40 cm = difficult airway + OSA risk)

Airway Assessment (Most Critical Step in Obese Patient)

Plan: Ramped position (ear-to-sternal notch); Video laryngoscopy; Difficult airway trolley available

Cardiovascular

• Blood pressure (both arms) - hypertension very common
• Heart rate (resting tachycardia suggests deconditioning or cardiac stress)
• JVP elevation, peripheral oedema (heart failure)
• Auscultate for murmurs (LVH → aortic stenosis, mitral regurgitation)

Respiratory

• SpO₂ on room air (baseline hypoxia common in morbid obesity)
• Respiratory rate
• Auscultate: wheeze, basal crackles (pulmonary oedema)
• Signs of chronic hypoxia (polycythaemia, cor pulmonale)

Abdomen

• Hepatomegaly (NAFLD/NASH)
• Previous surgical scars (adhesion risk)
• Assess abdominal girth
• Hernias (umbilical, incisional very common in obese)

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3. INVESTIGATIONS

Blood Tests

Cardiac Investigations

Respiratory Investigations

Additional Investigations

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4. RISK STRATIFICATION

ASA Grade

Revised Cardiac Risk Index (RCRI)

• Ischaemic heart disease (+1)
• Heart failure (+1)
• Cerebrovascular disease (+1)
• Insulin-dependent DM (+1)
• Creatinine >177 µmol/L (+1)

VTE Risk

• Obesity + major abdominal surgery = HIGH VTE risk
• Extended thromboprophylaxis (28 days) required

Metabolic Syndrome (Caprini/NCEP-ATP III)

• Obese patients with metabolic syndrome have significantly greater perioperative morbidity and mortality than obese patients without it

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5. OPTIMISATION BEFORE SURGERY

Weight Loss

• Even 5-10% weight loss before elective surgery improves:
  • Respiratory mechanics (FRC increases)
  • GORD symptoms
  • Blood glucose control
  • Cardiovascular risk
  • Wound healing
• Refer to bariatric dietitian if time permits

OSA (Obstructive Sleep Apnoea)

• Initiate CPAP therapy pre-operatively
• Patient must bring CPAP device to hospital on day of surgery
• Continue CPAP post-operatively (restart as soon as awake post-extubation)
• If untreated OSA → risk of post-op hypoxaemia, cardiac arrhythmia, respiratory arrest

GORD / Reflux

• PPI (omeprazole 40 mg OD) for 1 week before surgery
• Reduces gastric acid volume and pH → lessens aspiration pneumonitis severity
• Sodium citrate 30 mL oral on day of surgery (rapid-acting antacid)

Diabetes Control

• Target HbA1c <8.5% (69 mmol/mol) before elective major surgery
• HbA1c >10% → postpone if possible → optimise medically
• Perioperative insulin sliding scale
• Capillary blood glucose monitoring 1-2 hourly intra-op and post-op
• Target glucose: 6-10 mmol/L perioperatively

Hypertension

• Target BP <160/100 mmHg before elective surgery
• If BP >180/110 → postpone; optimise antihypertensives
• ECG + echo if uncontrolled or long-standing

Anaemia

• Treat iron deficiency: oral iron 6-8 weeks before; IV iron if time-limited (<6 weeks)
• Target Hb ≥10 g/dL before major surgery
• Transfuse if Hb <8 g/dL pre-op (symptomatic patient)

Smoking

• Stop ≥8 weeks before elective surgery - reduces post-op pulmonary complications
• Minimum 1-2 weeks reduces sputum volume
• Nicotine replacement therapy can be prescribed

Pre-operative Physiotherapy

• Inspiratory muscle training (IMT) - reduces post-op atelectasis and pneumonia
• Teach deep breathing, huffing, incentive spirometry
• Especially important in morbidly obese (severely reduced FRC)

Nutrition

• Obese patients can paradoxically be malnourished (calorie-dense but micronutrient-poor diet)
• Check serum albumin, prealbumin
• If albumin <30 g/L → nutritional support 7-10 days before major surgery
• Carbohydrate loading (200 mL oral CHO drink the night before + 200 mL 2h before surgery) - reduces insulin resistance, PONV, post-op catabolism (ERAS protocol)

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6. DAY OF SURGERY PREPARATION

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7. ANAESTHETIC CONSIDERATIONS (Communicate to Anaesthetist)

Airway Management Plan

• Pre-oxygenation: longer than standard (3-5 min 100% O₂); obese patients have reduced FRC → desaturate within 1-2 min of apnoea vs. 5-8 min in lean patients
• Positioning: Ramped position (ear-to-sternal notch aligned horizontally) - not flat supine - significantly improves laryngoscopic view
• Video laryngoscopy as first choice for intubation
• Rapid Sequence Induction (RSI) with cricoid pressure (full stomach/aspiration risk)
• Awake fibreoptic intubation if Mallampati IV + multiple predictors
• Difficult airway trolley in theatre: LMA, bougie, fibreoptic scope, surgical airway kit

Intraoperative Ventilation (Lung-Protective)

• Tidal volume: 6-8 mL/kg Ideal Body Weight (IBW) - NOT total body weight (avoids volutrauma)
• PEEP: 5-10 cmH₂O (prevents atelectasis - critical in obese patients)
• Recruitment manoeuvres after intubation and before extubation
• Reverse Trendelenburg position (head up) during surgery - improves diaphragm excursion and FRC
• Target SpO₂ >95% throughout

Drug Dosing in Obese Patients

LBW formula (males): 50 + 0.9 × (height in cm - 152) LBW formula (females): 45 + 0.9 × (height in cm - 152)

Gastric Aspiration Risk

• Obese patients: increased gastric volume + lower pH + GORD + raised intra-abdominal pressure
• RSI is the standard: rapid induction (propofol + succinylcholine) + cricoid pressure applied
• Avoid bag-mask ventilation if possible until airway secured

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8. POST-OPERATIVE PLAN

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SUMMARY - ONE PAGE OVERVIEW

HISTORY
  ✓ BMI, OSA (STOP-BANG ≥3?), GORD, DM, HTN, IHD, exercise tolerance (<4 METs?)
  ✓ Drugs: metformin, insulin, ACE-i, OCP - adjust accordingly

EXAMINATION
  ✓ Airway: Mallampati, neck circumference, thyromental distance, mouth opening
  ✓ SpO₂ on air, BP both arms, JVP, oedema, hepatomegaly

INVESTIGATIONS
  ✓ Bloods: FBC, U&E, LFT, glucose/HbA1c, TFTs, coag, albumin, G&S/XM
  ✓ ECG (all obese), CXR, Echo if indicated
  ✓ ABG if SpO₂ <94%
  ✓ Sleep study if STOP-BANG ≥3

OPTIMISE
  ✓ Initiate CPAP for OSA
  ✓ PPI for GORD
  ✓ HbA1c <8.5%, BP <160/100, treat anaemia
  ✓ Stop smoking ≥8 weeks
  ✓ Pre-op physiotherapy (IMT)
  ✓ Weight loss if time allows

DAY OF SURGERY
  ✓ Fasting: 6h solids, 2h fluids
  ✓ Antacid (sodium citrate + PPI)
  ✓ Antibiotics: higher dose (cefazolin 3g if BMI >40)
  ✓ DVT: TED stockings + IPC + LMWH (weight-adjusted)
  ✓ IV access (USS-guided if difficult)
  ✓ Consent, site marking, WHO checklist

ANAESTHESIA
  ✓ Ramped position + video laryngoscope
  ✓ RSI with cricoid pressure
  ✓ Lung-protective ventilation (6-8 mL/kg IBW + PEEP)
  ✓ Drug doses based on LBW (except suxamethonium + antibiotics = TBW)

POST-OP
  ✓ HDU, CPAP restart, O₂ monitoring
  ✓ Multimodal analgesia (minimise opioids)
  ✓ LMWH 28 days, early mobilisation Day 1
  ✓ Blood glucose control, early feeding, chest physio

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Physiological Changes During Pregnancy

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OVERVIEW

• Progesterone - smooth muscle relaxation, sedation, hyperventilation stimulus
• Oestrogen - vascular changes, fluid retention, mucosal engorgement
• Human Chorionic Gonadotropin (hCG) - early pregnancy support
• Human Placental Lactogen (hPL) - metabolic changes, insulin resistance
• Mechanical effects of the growing uterus

Stages of Pregnancy

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QUANTITATIVE SUMMARY TABLE

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1. CARDIOVASCULAR SYSTEM

Changes and Timing

• Peripheral vascular resistance (SVR) begins to fall (progesterone + oestrogen → vasodilation)
• Blood pressure drops slightly (5-10 mmHg below baseline)
• Heart rate begins to rise

• SVR reaches its nadir (lowest point) at mid-2nd trimester
• BP is at its lowest point
• Cardiac output rises significantly (HR + SV both increase)
• Plasma volume expanding rapidly

• BP returns towards baseline
• Cardiac output plateaus (does not rise much further until labour)
• Aortocaval compression becomes significant (supine position → uterus compresses IVC and aorta)

• Cardiac output increases a further 60-80% above pre-labour values
• Catecholamine release, uterine contractions (autotransfusion of 300-500 mL with each contraction), pain all drive CO up further
• Immediately post-delivery: autotransfusion from uterus → sudden CO rise

Specific Changes

Aortocaval Compression (Supine Hypotension Syndrome)

• After week 20, the gravid uterus compresses the inferior vena cava (IVC) when supine
• Reduces venous return → ↓ CO → hypotension
• 5% of term patients develop frank supine hypotension syndrome: pallor, sweating, nausea, dizziness
• Treatment: tilt patient to left lateral decubitus or place wedge (>15°) under right hip
• Also compresses aorta → ↓ uteroplacental perfusion → fetal asphyxia

Normal Cardiac Examination Findings in Pregnancy

• Collapsing arterial pulses
• Prominent JVP pulsations (without elevation)
• Laterally displaced apex beat
• Palpable RV or pulmonary trunk impulse
• Soft ejection systolic murmur (pulmonary area or left sternal edge) - due to increased flow
• ECG: sinus tachycardia, left axis deviation, T wave changes, non-specific ST changes - all normal

Postpartum

• Blood volume normalises in 1-2 weeks
• Cardiac output returns to normal in 2 weeks
• Complete haemodynamic resolution: up to 6 months
• Fluid mobilisation in week 1 post-delivery → risk of heart failure in women with underlying cardiac disease

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2. RESPIRATORY SYSTEM

Mechanism

Changes by Trimester

• Tidal volume begins to increase (progesterone effect)
• Minute ventilation rises progressively
• PaCO₂ begins to fall → chronic compensatory respiratory alkalosis
• Plasma HCO₃⁻ falls to compensate (renal compensation) → prevents severe alkalosis

• Uterus elevates the diaphragm
• FRC falls 20% (↓ expiratory reserve volume + ↓ residual volume)
• Chest wall compensates: anteroposterior diameter increases
• Diaphragmatic movement is NOT restricted
• CXR shows: prominent vascular markings + elevated diaphragm + apparent cardiomegaly

Specific Respiratory Changes

Upper Airway Changes (CRITICAL for Anaesthesia)

• Mucosal engorgement (oestrogen-driven) throughout the respiratory tract
• Nasal congestion, epistaxis more common
• Laryngeal and pharyngeal oedema - leads to difficult intubation
• Use smaller endotracheal tubes (6.0-6.5 mm) and gentle laryngoscopy
• Any nasal instrumentation risks significant bleeding

Key Anaesthetic Implications of Respiratory Changes

1. ↓ FRC + ↑ O₂ consumption → rapid O₂ desaturation during apnoea - mandatory pre-oxygenation before GA
2. PaCO₂ of 28-32 mmHg is normal in pregnancy - do not try to normalise to 40 mmHg on ventilator
3. Closing volume may exceed FRC in supine → atelectasis + hypoxaemia → avoid prolonged supine positioning

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3. HAEMATOLOGICAL SYSTEM

Changes

Physiological Purpose

• Hypercoagulability = protective adaptation to minimise haemorrhage at delivery (average blood loss: vaginal 200-500 mL; Caesarean section 800-1000 mL)
• Dilutional anaemia reduces blood viscosity → improves placental perfusion

Clinical Consequences

• DVT/PE risk is 5-10× higher in pregnancy (Virchow's triad: venous stasis, hypercoagulability, vessel wall changes)
• Iron deficiency and folate deficiency anaemias develop easily → supplements recommended throughout pregnancy
• Leukocytosis is normal → CRP and other markers needed to diagnose infection

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4. RENAL SYSTEM

Changes

Key Clinical Points

• Serum creatinine of 1.0 mg/dL (normal in non-pregnant) may indicate renal impairment in pregnancy
• Glucosuria is NORMAL - does not diagnose gestational diabetes (need OGTT)
• Physiological hydronephrosis (especially right-sided due to uterine dextrorotation) → predisposes to urinary stasis → risk of pyelonephritis from simple UTI

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5. GASTROINTESTINAL SYSTEM

Changes

Key Clinical Points

• Pregnancy is a full stomach anaesthetic situation from early 2nd trimester onward → RSI mandatory for GA
• Antacid prophylaxis (sodium citrate + PPI) essential before GA in any pregnant patient
• Obese pregnant women have compounded aspiration risk

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6. HEPATIC SYSTEM

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7. ENDOCRINE SYSTEM

Hormonal Changes

Thyroid Changes

• Thyroid enlarges (hypertrophy) - oestrogen + hCG stimulation
• TBG (thyroid-binding globulin) ↑ → total T3 and T4 ↑ (but FREE T3/T4 remain normal)
• Iodine requirements increase → relative iodine deficiency may occur
• TSH slightly ↓ in 1st trimester (hCG cross-reacts with TSH receptor)
• Net result: euthyroid state (normal free thyroid hormones) despite ↑ total levels

Pancreas / Glucose Metabolism

• Insulin secretion ↑ progressively (pancreatic beta-cell hyperplasia)
• Insulin resistance develops (due to hPL, progesterone, cortisol)
• Fasting blood glucose is lower in pregnancy (glucose consumed by fetus)
• Amino acids and glucose diverted to fetus → mother uses fat for energy → ↑ ketones, triglycerides, free fatty acids
• Pregnancy = diabetogenic state → reveals latent diabetes (gestational DM = GDM)

Adrenal Changes

• Cortisol ↑ (both bound and free)
• Aldosterone ↑ significantly (maintains Na balance despite GFR rise)

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8. NERVOUS SYSTEM

Key Anaesthetic Implications

• Less anaesthetic drug needed (↓ MAC) → risk of overdose if standard dosing used
• Spinal and epidural blocks spread higher than expected → reduce doses
• Increased risk of intravascular injection (engorged epidural veins)

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9. MUSCULOSKELETAL SYSTEM

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10. SKIN AND BREAST

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11. CHANGES DURING LABOUR AND DELIVERY

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QUICK REVISION TABLE - KEY EXAM FACTS

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