TOPIC 7 Nausea and vomiting

Written By Lokin Ho

Introduction

Postoperative nausea and vomiting is estimated to occur in 30% of patients undergoing surgery. It results in a poor patient experience, as well as longer hospital stay. As an intern, you will get a lot of short calls for nausea and vomiting.

Pathophysiology of nausea and vomiting

The pathophysiology of nausea and vomiting is complex and not well understood. It involves:

  • Central mechanism: vomiting center in the medulla.

  • Peripheral mechanism: gastric stimulation from trauma or noxious mediators causing the release of chemicals including substance P and serotonin.

The main neurotransmitter receptors involved in the nausea and vomiting pathway are:

  • Muscarinic M1

  • Dopamine D2

  • Histamine H1

  • 5-hydroxytryptamine (HT)-3 serotonin

  • neurokinin 1 (NK1) – substance P

Anti-emetics target these receptors.

Which patients are at the greatest risk of postoperative nausea and vomiting?

This can be divided into patient and surgical factors:

Patient specific risk factors

  • Female sex

  • Past history of motion sickness or postoperative nausea and vomiting

  • non smoker

  • young age – less than 50 years old

Surgical factors

  • Anesthetic technique- General Anesthesia

  • Use of volatile anesthetics

  • Long duration of surgery

  • Opioid use

  • Type of surgery (in particular Cholecystectomy, Gynaecological, Bariatric, Laparascopic surgery)

Pharmacological management of nausea and vomiting

You are called by the nursing staff to review Mrs A, who is vomiting, following hip replacement surgery 12 hours ago. What anti-emetic agents can you use?

Serotonin (5-hydroxytryptamine) receptor antagonists

Precautions: there have been reports of prolonged QT

Ondansetron

Dosage: PO/IV 4mg-8mg. Up to 16mg daily

Dopamine Antagonists

Precautions- pretty safe.

Metoclopramide

Dosage: PO/IV 10mg three times a day. Maximum dose of 30mg daily

Prochlorperazine

Dosage: IV 12.5mg 8 hourly PO 5-10mg 8 hourly

Histamine antagonists

Precautions- pretty safe

Cyclizine

Dosage IV 50mg 8 hourly

Promethazine

PO 25mg every 4 to 6 hourly. Maximum dose of 100mg daily

#TIP Use different classes of anti-emetics to treat nausea and vomiting. Using a combination approach is better than using a single anti-emetic agent alone

Resources
 Gan TJ, Belani KG, Bergese S, Chung F, Diemunsch P, Habib AS, Jin Z, Kovac AL, Meyer TA, Urman RD, Apfel CC, Ayad S, Beagley L, Candiotti K, Englesakis M, Hedrick TL, Kranke P, Lee S, Lipman D, Minkowitz HS, Morton J, Philip BK. Fourth Consensus Guidelines for the Management of Postoperative Nausea and Vomiting. Anesth Analg. 2020 Aug;131(2):411-448. doi: 10.1213/ANE.0000000000004833. Erratum in: Anesth Analg. 2020 Nov;131(5):e241. PMID: 32467512.
  Manahan MA, Johnson DJ, Gutowski KA, Bonawitz SC, Ellsworth WA 4th, Zielinski M, Thomsen RW, Basu CB. Postoperative Nausea and Vomiting with Plastic Surgery: A Practical Advisory to Etiology, Impact, and Treatment. Plast Reconstr Surg. 2018 Jan;141(1):214-222. doi: 10.1097/PRS.0000000000003924. PMID: 29280884.
 Melton MS, Klein SM, Gan TJ. Management of postdischarge nausea and vomiting after ambulatory surgery. Curr Opin Anaesthesiol. 2011 Dec;24(6):612-9. doi: 10.1097/ACO.0b013e32834b9468. PMID: 21934496.
  Shaikh SI, Nagarekha D, Hegade G, Marutheesh M. Postoperative nausea and vomiting: A simple yet complex problem. Anesth Essays Res. 2016;10(3):388-396. doi:10.4103/0259-1162.179310
Lokin Ho
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