Management of Postoperative Nausea

1
Management of Post-operative Nausea Vomiting
(PONV)

• Stephanie Jackson, M3

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Incidence of PONV

• Morphine, which is standardly used in
  patient-controlled analgesia (PCA), provides
  excellent control of patient postoperative pain.
  It is excellent in that patients use less drugs
  than if they were treated by medical staff.
• But morphine doesnt come without its side
  effects. The biggest being
• Postoperative Nausea Vomiting

3
Facts

• PONV increases
• Time spent in recovery
• Need for nurses
• Need to admit overnight
• This all leads to increased healthcare costs.
• More than 25 of patients report experiencing
  PONV, with numbers reaching as high as 80 in
  high risk populations.

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PONV risk factors

• Female gender
• Nonsmoking status
• History of motion sickness or PONV
• Use of postoperative opioids
• Type of surgical procedure (e.g. ambulatory
  gynecologic laparoscopy reports 88)

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Available Drugs

• Phenergan (Promethazine) H1 antagonist, central
  peripheral
• Kytril (Granisetron) serotonin (5-HT3)
  inhibitor, given IV in cancer pts
• Anzemet (Dolasetron) serotonin (5-HT3)
  inhibitor
• Zofran (Ondansetron) - serotonin (HT3) inhibitor
• Inapsin (Droperidol) inhibits DA a receptors
• Reglan (Metoclopramide) stimulates upper GI
  motility

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Intravenous crystalloid infusion

• Prospective, randomized, double-blind clinical
  investigation
• 30ml/kg vs 10 ml/kg infusion to combat
  preoperative hypovolemia.
• Preoperative fasting creates a hypovolemic state
  that causes under-perfusion of gastric mucosa
  delaying return of bowel function.
• They found that 30mg/kg significantly reduced
  PONV at 0.5h 48h.
• Magner et al., British Journal of Anaethesia, 93
  (3) 381-5 (2004)

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Advantages of CSL-30

• Inexpensive, non-pharmacological therapy
• Eliminates adverse drug effects side-effects
• Magner et al., British Journal of Anaethesia, 93
  (3) 381-5 (2004)

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Dolasetron vs. Ondansetron

• 12.5 mg iv Dolasetron vs 4 mg iv Ondansetron
• Dolasetron was found to be more effective,
  requiring less rescue emetics
• Price comparison including cost of rescue emetics
  showed Dolasetron as being more cost-effective.
• 4 major hospitals in Washington saved 500,000
  over 1 year
• Meyer et al, Anesth Analg 2005 100373-7

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Dexamethasone vs Droperidol

• A study compared Droperidol with varied doses of
  Dexamethasone.
• 2 mg 4 mg of Dexamethasone showed no difference
  compared to saline.
• 8 mg 12 mg Dexamethasone 0.10 mg of
  Droperidol all reported higher patient
  satisfaction by reducing N/V.
• Higher doses of Droperidol cause excessive
  sedation.
• Lee Et Al, Anesth Anal 2004 981066-71

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Dexamethasone vs Droperidol

• Complete response (no post-op N/V, no need for
  rescue emetics) was shown at 72.2 for 8 mg
  78.9 for 12 mg of Dexamethasone compared to
  42.9 for saline.
• In 2001 the FDA gave Droperidol and black box
  warning related to cardiac toxicity (QT
  prolongation.
• Lee Et Al, Anesth Anal 2004 981066-71

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Granisetron vs. Ramosetron

• 0-24 hrs after anesthesia
• 17 with granisetron
• 10 with ramosetron
• 47 with placebo
• 24-48 hrs after anesthesia
• 27 with granisetron
• 7 with ramosetron
• 53 with placebo
• Not available in the US
• Fujii et al, American Journal of Therapeutics
  (2004) 11(4)

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Cimetidine

• Cimetidine, an H2 antagonist, has been used to
  increase gastric pH reduce gastric volume to
  avoid aspiration due to anesthesia.
• Cimetidine has also shown elicit antinociception.
• A pre-op group received 4mg/kg preoperatively,
  while the post-op group received saline.
  Postoperatively the pre-op group received saline,
  while the post-op group received 4mg/kg of
  cimetidine.
• The control group received saline both pre-
  post- operatively.
• They found no difference in either group.
• Y-Y. Chia et al., Acta Anaesthesiol Scand 2005
  49 865-869

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PCA diphenhydramine

• Diphenhydramine blocks muscarinic-cholinergic
  receptors in the vestibular pathways and vomiting
  center.
• Diphenhydramine was added to the morphine at a
  diphenhydramine-to-morphine ratio of 4.81 (group
  3) 1.21 (group 2) to women who had undergone
  total abdominal hysterectomies.
• Group 3 showed significant improvement, while
  Group 2 showed no improvement over group 1
  (normal saline).
• Nausea 31.6 (group 3) vs 67.6 (group 1)
• Vomiting 15.8 (group 3) vs. 40.5 (group 1)
• Severe nausea 2.6 (group 3) vs 24.3 (group 1)
• Rescue antiemtics 5.3 (group 3) vs 24.3 (group
  1)
• Lin et al., British Journal of Anaesthesia 94
  (6) 835-9 (2005)

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Cost Comparison

• Phenergan (Promethazine) 12.5mg 0.37, 25mg
  0.60 ,50mg 0.90
• Kytril (Granisetron) 1mg 50.00
• Anzemet (Dolasetron) 50mg 54.58, 12mg
  13.65
• Zofran (Ondansetron) 4mg 22.30
• Inapsin (Droperidol) unknown
• Reglan (Metoclopramide) 5mg 0.72, 10mg
  1.17

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Summary

• 30ml/kg of intravenous crystalloid infusion vs 10
  ml/kg
• Dolasetron vs. Ondansetron
• Ramosetron vs. Granisetron
• Dexamethasone vs. Droperidol
• Diphenhydramine

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Other factors to research in the future

• Smoking as an anti-emetic
• PONV affected by female sex hormones