Causes of Post-Operative Vomiting After Total Abdominal Resection (TAR)
Post-operative vomiting after total abdominal resection is caused by a combination of patient-specific risk factors (female sex, non-smoking status, history of motion sickness or PONV), anesthetic factors (volatile anesthetics, nitrous oxide), surgical factors (major abdominal surgery, prolonged operative time), and postoperative opioid administration. 1, 2
Patient-Specific Risk Factors
The Apfel score identifies four key patient risk factors, each contributing one point to the total risk assessment: 2
- Female sex - Women have significantly higher baseline PONV risk 1, 2
- Non-smoking status - Non-smokers experience more PONV than smokers 1, 2
- History of motion sickness or previous PONV - Prior episodes predict future occurrence 1, 2
- Postoperative opioid use - Opioid analgesics are a major modifiable risk factor 1, 2
Patients with an Apfel score ≥2 have moderate to high risk and require prophylactic antiemetic therapy. 2
Anesthetic Factors
The type of anesthesia significantly influences PONV incidence: 1, 3
- Volatile anesthetic agents (isoflurane, sevoflurane, desflurane) substantially increase PONV risk compared to total intravenous anesthesia (TIVA) with propofol 1, 3
- Nitrous oxide increases PONV risk and should be avoided 2
- Inhalational anesthesia causes PONV in 50.9% of patients undergoing abdominal surgery versus only 17.3% with TIVA (p < 0.001) 3
Surgical Factors
Major abdominal surgery itself is an independent risk factor: 1
- Type of surgery - Total abdominal resection qualifies as major abdominal surgery, which inherently increases PONV risk 1
- Duration of surgery - Procedures exceeding one hour duration increase PONV incidence 1
- Surgical trauma - Manipulation of abdominal viscera and peritoneal irritation contribute to postoperative nausea and vomiting 4
Postoperative Factors
Several postoperative elements perpetuate or trigger vomiting: 1
- Opioid administration - Postoperative opioids are the single most important modifiable risk factor, with each opioid dose increasing PONV probability 1, 2
- Early mobilization - While beneficial overall, early mobilization without adequate PONV prophylaxis can trigger symptoms 1
- Inadequate hydration - Hypovolemia and dehydration worsen PONV 2
Mechanism of Action
The pathophysiology involves multiple neurotransmitter systems: 1, 5
- Serotonin (5-HT₃) receptors - Surgical trauma releases serotonin from enterochromaffin cells, triggering the vomiting reflex 5
- Dopamine (D₂) receptors - Activated in the chemoreceptor trigger zone by anesthetics and opioids 5
- Neurokinin-1 (NK₁) receptors - Substance P binding in the vomiting center contributes to PONV 5
- Histamine and acetylcholine receptors - Involved in motion-related and vestibular-mediated nausea 5
Critical Clinical Pitfall
Do not assume all post-TAR vomiting is simple PONV. Persistent vomiting beyond 48 hours despite maximal medical therapy, especially when accompanied by fever ≥38°C, tachycardia ≥110 bpm, severe abdominal pain, or inability to tolerate oral intake, strongly suggests surgical complications such as anastomotic leak, bowel obstruction, or intestinal ischemia requiring immediate imaging evaluation. 6
Risk Stratification for TAR Patients
Most patients undergoing total abdominal resection will have multiple risk factors: 1, 2
- Major abdominal surgery automatically confers one risk factor 1
- Female patients add a second risk factor 1, 2
- Postoperative opioid use (nearly universal in TAR) adds a third risk factor 1, 2
- Non-smoking status or PONV history may add a fourth risk factor 1, 2
Therefore, most TAR patients qualify as moderate-to-high risk (Apfel score 2-4) and require multimodal prophylaxis with 2-3 antiemetics from different drug classes. 1, 2