This is a plain English summary of an original research article
Post-operative vomiting is common in children. One strategy is to use an intravenous anaesthetic, which is known to cause lower rates of sickness than inhaled anaesthetics. There are disadvantages to this though, such as the need for injections before a child is asleep, slowing of the heart and difficulty in monitoring depth of the anaesthetic.
This review of four trials included 558 children who had an operation to correct a squint. A third of children in each anaesthetic group had post-operative vomiting. There was no difference in time spent in the recovery room.
The results indicate that individual factors may be more important when deciding on which type of anaesthetic to use rather than risk of post-operative vomiting.
Why was this study needed?
Post-operative vomiting is common in children, occurring in approximately 13 to 42% of cases. Nausea is probably commoner still, but young children may find it hard to explain they feel unwell. Nausea and vomiting are the leading reasons for unplanned admission after day surgery.
Inhaled anaesthetics such as isoflurane and sevoflurane are associated with an increased risk of vomiting compared to intravenous anaesthetics, so for children or types of surgery with high-risk factors for vomiting, including squint surgery, an intravenous anaesthetic may be chosen.
This review aimed to see to what extent giving preventative anti-sickness medication with inhalation anaesthetic reduced the risk of vomiting compared with an intravenous anaesthetic in children undergoing squint surgery.
What did this study do?
This systematic review and meta-analysis pooled the results of four randomised controlled trials. They included 558 children having surgery to correct a squint, all from Western countries, though none from the UK.
Children were randomised to either intravenous anaesthetic, propofol, with or without alfentanil (a pain killer) or inhaled anaesthetic plus anti-sickness medication – ondansetron or droperidol. The inhaled anaesthetic was halothane in three studies and isoflurane with alfentanil in one study. The studies were performed between 1991 and 1998, but it is unlikely that results would be substantially different for different anaesthetic or anti-sickness medication.
Nitrous oxide was also used in three of the studies. There is conflicting evidence on the effect of nitrous oxide on post-operative vomiting, so this may have affected results.
What did it find?
- There was no difference in the proportion of children who had post-operative vomiting: 33% intravenous anaesthetic group versus 32% inhalation anaesthetic plus antiemetic group (risk ratio 0.99, 95% CI 0.77 to 1.27; 4 trials, 558 children).
- A similar amount of time was spent in the post-anaesthesia unit (mean difference ‑8.93 minutes, 95% CI ‑22.0 to 4.18).
- No other adverse events were reported in the trials.
What does current guidance say on this issue?
The Association of Paediatric Anaesthetists of Great Britain & Ireland (2016) suggest intravenous anaesthesia is considered in children at high risk of sickness. This includes children who have previously had post-operative vomiting, motion sickness, older children and post-pubertal girls.
Higher risk surgical procedures include those lasting more than 30 minutes, squint correction and removal of the adenoids and tonsils.
They recommend ondansetron as medication for children at increased risk. It can also be given to treat post-operative sickness. For those at high risk, the addition of dexamethasone is recommended.
What are the implications?
Inhaled anaesthesia with anti-sickness medication in children has the same risk of vomiting as intravenous anaesthesia, although giving anti-sickness medication with an intravenous anaesthetic, or using more than one anti-sickness medication in either group, may further reduce the risk of vomiting.
Squint surgery has one of the highest rates of post-operative vomiting – on average 59% without any preventive treatment. It remains unclear if similar results would be found for other types of surgery.
Although the studies included used only a few of the available medications, there is good evidence in adults that no single agent is more effective than another and some evidence on the same lines in children. A multimodal approach avoiding known triggers where possible and using a combination of anti-sickness medications may be the best strategy.
Citation and Funding
Schaefer MS, Kranke P, Weibel S, et al. Total intravenous anesthesia vs single pharmacological prophylaxis to prevent postoperative vomiting in children: A systematic review and meta-analysis. Pediatr Anaesth. 2017;27(12):1202-09.
This project was funded by the University Hospital Düsseldorf ad the University Hospital Würzburg.
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