Post-Operative Complications

Overview – Post-Operative Complications

Post-operative complications refer to the array of medical and surgical issues that can arise following any operative procedure. These range from early complications in the recovery room (such as respiratory depression or hypotension) to delayed infections, wound issues, and thromboembolic events. Prompt recognition and management are essential to reduce morbidity, mortality, and hospital stay.

Definition

Post-operative complications encompass any adverse event occurring as a direct consequence of surgery or anaesthesia. These may be immediate (within hours), early (within days), or late (within weeks).

Early Complications – In Recovery

Nausea and Vomiting

  • Occurs in <20% of patients
  • Risk Factors: Young age, female sex, history of motion sickness
  • Causes: Opioids, nitrous oxide
  • Treatment: Antiemetics (Ondansetron, Metoclopramide)

Respiratory

  • Respiratory depression → opioids or residual neuromuscular blockade
  • Aspiration → due to reduced cough reflex or gastric content reflux
  • Obstruction → laryngospasm, clots, or foreign bodies
  • Others: Atelectasis, pneumothorax, pulmonary embolism

Cardiovascular

  • Hypotension → hypovolaemia, haemorrhage, third spacing, left ventricular failure, ischaemic heart disease, ACE inhibitors
  • Hypertension → pain, stress, hypoxia, fluid overload, pre-eclampsia, hyperthyroidism, raised intracranial pressure
  • Arrhythmias → electrolyte disturbances, drug effects

Pain

  • Treated with opioids as required

Hypothermia

  • Causes: Exposure, anaesthesia-induced thermoregulatory disruption
  • Treatment: Warming measures, oxygen, IV pethidine

Late Complications – In Ward or Post-Discharge

Wound Complications

  • Haematoma → often due to poor haemostasis; risk for infection (particularly dangerous in neck surgeries)
  • Infection → day 5–10; risk factors include diabetes, steroids, smoking
    • Treatment: Flucloxacillin, Gentamicin, Vancomycin
  • Dehiscence → due to infection, suture failure, or poor wound closure

Respiratory

  • Atelectasis → common on day 2; more likely in elderly, obese, or smokers
    • Features: Fever, tachypnoea, tachycardia
    • Treatment: Incentive spirometry
  • Pneumonia → often follows atelectasis or aspiration
    • 30% mortality
    • Treatment: Oxygen, Cephalexin

Vascular

  • Deep Vein Thrombosis (DVT)
    • Pathophysiology: Virchow’s triad (stasis, vessel injury, hypercoagulability)
    • Risk factors: Age, surgery, oral contraceptive pill, hormone replacement therapy, cardiovascular disease
    • Features: Pain, swelling
    • Diagnosis: Doppler ultrasound
    • Treatment: Heparin and Warfarin
  • Pulmonary Embolism (PE)
    • Source: DVT embolisation
    • Features: Dyspnoea, chest pain, tachycardia, hypotension
    • Diagnosis: CT pulmonary angiogram
    • Treatment: Thrombolysis + Heparin or pulmonary embolectomy

Cardiovascular

  • Myocardial Infarction (MI)
    • Risk: Higher in vascular surgery, hypotension, or hypoxia
    • Features: Often silent; ECG shows ST depression
    • Diagnosis: Troponin-I
    • Treatment: Oxygen, Morphine, Glyceryl Trinitrate (GTN), Aspirin

Abdominal

  • Ileus
    • Cause: Physical bowel handling, opioid use, aortic surgery
    • Treatment: Nil by mouth, nasogastric tube if required

Central Nervous System

  • Post-op confusion in elderly

Post-Operative Fever and Infection

The 5 W’s of Post-Op Fever

  • Day 1 – Wind: Atelectasis, pneumonia
  • Day 2 – Water: Urinary tract infections (from catheters)
  • Day 3 – Walking: Deep vein thrombosis
  • Day 4 – Wound: Wound infections
  • Day 5 – Wonder Drugs: Drug-induced fever

Prevention Strategies

  • Wind: Early mobilisation, incentive spirometry, antibiotics if pneumonia develops
  • Water: Remove indwelling catheters promptly
  • Walking: Heparin/low-molecular-weight heparin, compression stockings, early ambulation
  • Wounds: Prophylactic antibiotics (Cephalexin, Gentamicin, Metronidazole), wound hygiene
  • Wonder Drugs: Review medications; monitor for drug-induced fever

Infection Screening and Management

Common Sources

  • Abdomen: Peritonism
  • Chest: Cough, hypoxia, crackles
  • Urinary Tract: Dysuria, frequency, urgency, pelvic pain
  • Wound/IV/Catheter sites: Look for erythema, discharge, heat
  • Meningism: Neck stiffness, headache, photophobia
  • Endocarditis: Janeway lesions, Osler’s nodes, splinter haemorrhages

Examination

  • Vitals: Fever, tachycardia, hypotension
  • Respiratory exam
  • Inspect all lines and wounds

Investigations

  • Full blood count (WBC)
  • Cultures: Blood, wound, sputum
  • Urine microscopy, culture, sensitivity
  • Chest X-ray

Targeted Antibiotic Therapy

Gram-Positive (Skin/Throat)

  • Organisms: Enterococcus, Staph, Strep
  • First-line: Penicillins (Flucloxacillin), Cephalosporins
  • Resistant cases: Vancomycin

Gram-Negative (GI/UTI)

  • Organisms: E. coli, Klebsiella, Haemophilus
  • Agents: Aminoglycosides, Tetracyclines, Macrolides, Quinolones, Cephalosporins

Anaerobes

Atypicals

  • Organisms: Mycoplasma, Legionella
  • Agents: Macrolides, Tetracyclines

Notable Infections

  • Wound Infections/Cellulitis: Flucloxacillin, Gentamicin, Vancomycin (if MRSA)
  • Abdominal Infections: Gentamicin, Doxycycline, Metronidazole, Ampicillin
  • UTI: Ciprofloxacin
  • Osteomyelitis/Septic Arthritis: Flucloxacillin, Gentamicin, Vancomycin (if MRSA)

Triple Therapy (AGM): Ampicillin + Gentamicin + Metronidazole – Broad-spectrum for serious intra-abdominal or mixed infections

post-operative complications: Post-Op Infection Antibiotics

Summary – Post-Operative Complications

Post-operative complications range from immediate risks like respiratory depression and hypotension to delayed events including wound infections, DVT, and confusion. Effective prevention strategies, careful monitoring, and targeted antibiotic treatment are essential to improve patient outcomes. For a broader context, see our Emergency Medicine Overview page.

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