PREVENTION OF PONV
R11.2
Patients identified preoperatively as medium or high risk for PONV should be considered for prophylactic antiemetics.
Prophylactic antiemetics also required if postoperative vomiting is potentially dangerous, e.g. after jaws wired, open eye surgery, oesophageal surgery.
High risk patients should receive anti-emetics from ≥ 1 class.
Adequate IV hydration associated with less PONV.
| Risk factors for PONV | Points |
|---|---|
| Female Gender | 1 |
| Non-Smoker | 1 |
|
History of PONV and/or motion sickness |
1 |
| Postoperative opioids | 1 |
| Sum | 0-4 |
| Points | Risk for PONV (%) | Risk category |
|---|---|---|
| 0 | 10 | Low |
| 1 | 20 | Low |
| 2 | 40 | Medium |
| 3 | 60 | High |
| 4 | 80 | High |
| Class | Anti-emetic |
Prophylactic Dose and timing |
Notes |
|---|---|---|---|
|
Corticosteroid (glucorticoids) |
e.g. Dexamethasone |
4-8 mg, IV, on induction *LoEII [32] |
Increases blood glucose in diabetics. Only used for prophylaxis, not established PONV. |
|
5-HT 3 receptor antagonist |
e.g. Ondansetron | 4–8 mg, slow IV/IM, on induction. Reference ***LoEII [33] | Prolongs QTc interval |
| Phenothiazine | Promethazine |
6.25–12.5 mg, IV (large bore cannula) diluted to 20 mL over 10-20 minutes, or deep IM, at end of surgery. |
Intra-arterial injection causes gangrene. Extravasation or subcutaneous injection associated with skin necrosis. Anticholinergic side effects and sedation. |
** LoEIII [33]
TREATMENT OF PONV
R11.2
Ensure adequate hydration and correct hypotension if present.
Give an emetic from a different class than the prophylactic agent given (except dexamethasone, which is only used for prophylaxis).
- Metoclopramide, IM/IV
- If < 60kg: 5mg IM or IV (over 2 minutes).
- If ≥ 60kg: 10mg IM or IV (over 2 minutes).
- Repeat 8 hourly if required.
Note: Metoclopramide can cause extrapyramidal side effects.
Treat acute dystonic reactions with :
- Anticholinergic agent, e.g.:
- Biperiden, IM/IV, 2 mg.
- Repeat as necessary.
If an anticholinergic agent is not available :
- Promethazine, deep IM, 25–50 mg.
- In the elderly 25 mg.
If an anticholinergic agent or promethazine is not available :
- Diazepam, IV, 5–10 mg for symptom relief.