Background Preoperative oral carbohydrate loading is thought to reduce postoperative nausea and vomiting (PONV). However, it is unknown if the benefit of carbohydrate loading is maintained in the presence of total intravenous anaesthesia (TIVA). The aim of this systematic review was to determine whether oral carbohydrate loading reduced PONV compared to overnight fasting between adult elective surgery patients receiving TIVA or inhalational general anaesthesia.

Methods A search of seven databases was conducted until March 2024. Randomised controlled trials conducted with patient aged 18 years or older were included. Two reviewers independently screened titles, abstracts and full texts, and assessed risk of bias using the Cochrane ROB-2 Tool. Study data was pooled using random effects meta-analyses.

Results We included 26 studies in this review, and 25 in the meta-analyses (n=2,491). Preoperative oral carbohydrate loading reduced the overall risk (log risk ratio: –0.41, 95% CI –0.72 to –0.11, I2=30.92%) and severity (SMD: -0.46, 95% CI: -0.71 to -0.21, I2=66.59) of PONV, and pain severity (mean difference: -0.68, 95% CI: -1.13 to -0.22, I2=85.32%) compared to prolonged fasting when pooled across both anaesthesia approaches. The risk of PONV was reduced in patients receiving inhalational anaesthesia, but not TIVA, while the reduction in severity was more significant in TIVA.

Conclusion Oral carbohydrate loading reduces the severity of PONV and pain, regardless of the anaesthesia approach, compared to prolonged fasting. These findings support the clinical advantages of oral carbohydrate loading for postoperative outcomes, regardless of anaesthesia approach.

The authors have declared no competing interest.

This research was supported by the Australian College of Perioperative Nurses 2021 Research Grant and the Australian College of Perianaesthesia Nurses 2023 Research Grant. Mitchell Sarkies is supported by an NHMRC Investigator Grant (CIA Sarkies 2007970) and Sydney Horizon Fellowship.

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I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

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