What is the best approach to prevent postoperative nausea and vomiting in an elderly patient with impaired cardiac and respiratory function undergoing hip replacement surgery?

Prevention of Postoperative Nausea and Vomiting in Elderly Hip Replacement Patients

For an elderly patient with impaired cardiac and respiratory function undergoing hip replacement, implement a multimodal antiemetic strategy combining dexamethasone with ondansetron or droperidol, while strictly avoiding medications that precipitate delirium (benzodiazepines, anticholinergics like cyclizine) and minimizing opioid exposure through regional analgesia techniques. 1, 2

Risk Assessment and Baseline Considerations

• Elderly patients with cardio-/cerebrovascular disease and multimorbidity face significantly elevated risk of postoperative delirium (POD), which is precipitated by common antiemetics including anticholinergics (cyclizine) and benzodiazepines. 3, 1

• Document baseline cognitive function pre-operatively, as recovery room delirium strongly predicts postoperative delirium and elderly patients are at higher risk if they are frail, cognitively impaired, or have cardiovascular disease. 3

• The impaired cardiac and respiratory function in this patient necessitates careful drug selection, as hypotension from anesthesia is a common cause of intraoperative nausea and vomiting. 3

Intraoperative Prevention Strategy

Hemodynamic Optimization (First-Line Prevention)

• Administer fluid preloading with crystalloid or colloid, intravenous ephedrine or phenylephrine for blood pressure support, and apply lower limb compression (bandages, stockings, or inflatable boots) to reduce anesthesia-related hypotension. 3

• These interventions are effective in reducing both hypotension and the incidence of intraoperative and postoperative nausea and vomiting (moderate evidence, strong recommendation). 3

• Maintain continuous arterial line monitoring in elderly patients, as poorly compliant vasculature makes non-invasive measurements unreliable. 1

Pharmacologic Prophylaxis (Multimodal Approach)

Combination antiemetic therapy is superior to monotherapy and should be standard practice. 3, 2

Recommended Drug Combinations:

• Dexamethasone (recommended or high dose) combined with ondansetron (recommended or high dose): High-certainty evidence shows dexamethasone reduces vomiting (RR 0.51, rank 8/28) and ondansetron reduces vomiting (RR 0.55, rank 13/28). 2

• Alternative: Dexamethasone combined with droperidol (recommended or high dose): Moderate-certainty evidence shows droperidol probably reduces vomiting (RR 0.61, rank 20/28) and may reduce any adverse events. 2

• Combination regimens (5-HT₃ antagonists combined with either droperidol or dexamethasone) are significantly more effective than 5-HT₃ antagonists alone. 3

Specific Drug Considerations for Elderly Cardiac/Respiratory Patients:

• Ondansetron is FDA-approved for prevention of postoperative nausea and vomiting in patients aged 1 month and older, with no specific cardiac contraindications at standard doses. 4

• Ondansetron probably increases headache (RR 1.16, moderate certainty) but probably reduces sedation (RR 0.87, moderate certainty), which is beneficial in elderly patients at risk for delirium. 2

• Droperidol probably reduces headache (RR 0.76, moderate certainty) and may reduce any adverse events (RR 0.89, low certainty). 2

• Dexamethasone has high-certainty evidence of no effect on sedation (RR 1.00), making it safe for elderly patients. 2

• Metoclopramide is FDA-approved for prophylaxis of postoperative nausea and vomiting but should be used cautiously as it is a dopamine antagonist with potential extrapyramidal effects. 5

Drugs to AVOID in Elderly Patients:

• Strictly avoid anticholinergic agents (scopolamine, cyclizine) despite their efficacy for postoperative nausea and vomiting, as they precipitate delirium in elderly patients. 3, 6

• Avoid benzodiazepines (midazolam), as they precipitate delirium. 3

• Minimize or avoid sedative hypnotics and high-dose corticosteroids, which can precipitate delirium. 3

Anesthetic Technique Modifications

• Use depth of anesthesia monitoring (BIS or entropy) to prevent relative anesthetic overdose, as elderly patients require lower doses but commonly receive standard doses leading to prolonged hypotension. 1

• Consider regional anesthesia techniques (spinal or epidural with long-acting intrathecal opioids) to reduce systemic opioid requirements, as opioids precipitate delirium and contribute to nausea. 3

• Avoid volatile anesthetics if possible, or minimize their use, as they contribute to postoperative nausea and vomiting. 7

Postoperative Management

Pain Control (Critical for PONV Prevention)

• Implement multimodal analgesia starting with scheduled paracetamol (acetaminophen) as first-line therapy, as inadequate analgesia contributes to postoperative morbidity including delirium. 3, 1

• Use low-dose NSAIDs cautiously only if paracetamol is ineffective, at the lowest dose for shortest duration with proton pump inhibitor gastric protection and routine monitoring for gastric and renal damage. 3, 1

• Minimize opioid use to 25-50% of standard doses with close monitoring for respiratory depression, hypotension, and altered mental status, as opioids precipitate delirium and worsen nausea. 3, 1

• Maintain peripheral nerve blocks or spinal analgesia effects from the operative period. 6

Rescue Antiemetic Therapy

• For breakthrough nausea and vomiting despite prophylaxis, ondansetron may be given to prevent further episodes. 4

• Metoclopramide 20 mg is highly effective for rescue therapy but monitor for extrapyramidal symptoms in elderly patients. 3, 5

Delirium Prevention Bundle

• Screen for delirium in the recovery room using DSM-IV criteria or short-CAM (confusion assessment method), as recovery room delirium strongly predicts postoperative delirium. 3

• Continue early oral nutrition rather than routine intravenous fluids to facilitate recovery. 3, 6

• Remove urinary catheters as soon as possible to reduce infection risk and facilitate mobilization. 6

Dose-Specific Recommendations

Low doses of antiemetics show no clinically important benefit; use recommended or high doses: 2

• Ondansetron: Recommended (4-8 mg IV) or high doses (>8 mg IV) show clinically important benefit; low doses (<4 mg) do not. 2

• Dexamethasone: Recommended (4-5 mg IV) or high doses (>5 mg IV) show clinically important benefit; low doses (<4 mg) do not. 2

• Droperidol: Recommended (0.625-1.25 mg IV) or high doses (>1.25 mg IV) show clinically important benefit; low doses (<0.625 mg) do not. 2

• Granisetron: Recommended (0.35-1 mg IV) or high doses (>1 mg IV) show clinically important benefit; low doses (<0.35 mg) do not. 2

Common Pitfalls to Avoid

• Do not use routine prophylaxis with anticholinergics (cyclizine, scopolamine) in elderly patients despite their efficacy, as the risk of delirium outweighs antiemetic benefit. 3, 6

• Do not rely on single-agent prophylaxis; multimodal management with 98% complete response rate is superior to monotherapy. 8

• Do not use low doses of antiemetics expecting efficacy; dose-response relationships are clear for ondansetron, dexamethasone, droperidol, and granisetron. 2

• Do not delay addressing hypotension, as it is a primary cause of intraoperative nausea and vomiting that undermines pharmacologic prophylaxis. 3

• Do not use liberal opioid analgesia without multimodal pain strategies, as opioids both precipitate delirium and worsen nausea in elderly patients. 3, 7