Pre-operative Carbohydrate Loading May Ease Nausea and Enhance Recovery in Surgical Patients: Study

Why do so many patients wake up from surgery feeling nauseated and uncomfortable, despite modern anesthesia? Post-operative nausea and vomiting (PONV) remains a persistent challenge, prolonging recovery and hospital stays. Traditionally, patients have been asked to fast overnight before surgery, but could a simple carbohydrate drink before anesthesia change the game? A new systematic review and meta-analysis in the Indian Journal of Anaesthesia sheds light on this timely question.

Study Design: A Comprehensive Look at Carbohydrate Loading

This robust meta-analysis synthesized data from 98 randomized controlled trials—including nearly 10,000 adult surgical patients—to evaluate the effects of pre-operative oral carbohydrate loading compared to traditional fasting or placebo drinks. The main focus was on the reduction of PONV, but the analysis also explored hunger, thirst, pain, blood sugar control, insulin resistance, and length of hospital stay. The authors followed rigorous methods, including GRADE assessment for evidence quality.

Key Findings: Modest Benefits, Uncertain Clinical Impact

PONV Reduction: Patients who received a carbohydrate drink before surgery had a lower incidence of PONV (Risk Ratio 0.74), but this benefit was not confirmed in sensitivity analyses limited to high-quality studies.

Comfort Measures: Carbohydrate loading significantly reduced pre-operative hunger and thirst scores (on a 0–10 scale), suggesting improved patient comfort.

Metabolic Outcomes: There were modest improvements in post-operative glucose levels and insulin resistance, indicating a potential metabolic benefit.

Pain and Length of Stay: Small reductions were seen in post-operative pain and hospital stay (about 0.4 days shorter), though these differences may not be clinically meaningful for most patients.

Safety Considerations: No significant increase in residual gastric volume was found, supporting the safety of oral carbohydrate drinks up to 2 hours pre-op in most adults.

Limitations: Evidence Certainty and Heterogeneity

It’s important to note that the certainty of evidence was low to moderate for most outcomes, mainly due to high variability between studies, possible publication bias, and the inability to separate the effects of carbohydrate from other aspects of enhanced recovery protocols. The magnitude of benefit, especially for PONV and pain, was small and of uncertain clinical significance.

Clinical Implications: What Should Clinicians Do?

For clinicians, these findings suggest that pre-operative carbohydrate drinks may improve patient comfort and metabolic stability without increasing risk. However, the clinical impact on major outcomes like PONV and length of stay is likely limited in most cases. Tailoring the approach to patient risk profiles, surgical context, and institutional protocols remains key.

Conclusion

Pre-operative oral carbohydrate loading appears to offer some benefits in reducing discomfort and metabolic stress for surgical patients. Yet, due to low-certainty evidence and minimal effect sizes, clinicians should interpret these findings cautiously and continue to individualize perioperative care.

KEY points

Pre-operative carbohydrate drinks may lower PONV risk, but this is not confirmed in high-quality studies.

Patients report less hunger and thirst before surgery when given carbohydrate drinks.

Metabolic markers (glucose and insulin resistance) show modest improvement with carbohydrate loading.

The reduction in post-op pain and hospital stay is small and may not be clinically significant.

Safety data are reassuring, but further research is needed for optimal protocols and patient selection.

Citation:

Ng KT, Chia TH, Heng ES, Zainal Abidin MF. The impact of pre‑operative oral carbohydrate loading on peri‑operative outcomes: A systematic review and meta‑analysis of randomised controlled trials. Indian Journal of Anaesthesia. 2026;70(9):985-97. DOI: 10.4103/ija.ija_694_26