Preoperative oral rehydration solutions (ORS) are frequently used in clinical practice in Japan, although their effect remains to be explained.

The aim of a study published in the Journal of Clinical Anesthesia was to investigate the clinical outcomes associated with ORS usage.

This was a systematic review and meta-analysis of studies conducted in surgical departments of hospitals. Overall, 546 patients with American Society of Anesthesiologists physical status classification I or II (non-pregnant adults only) were reported in six articles. Patients in the included studies had originally been randomly allocated to preoperative ORS or control group. The outcome measures were the incidence of aspiration and vomiting during induction of anesthesia, gastric fluid volume (absolute volume), gastric pH, stroke volume variation (SVV) during induction of anesthesia. Risk difference (RD) or mean difference (MD) with 95% confidence interval (CI) were calculated using a random effects model.

It was observed that there was no aspiration or vomiting in either group – 3 studies, 428 patients, RD 0 (95% CI -0.01 to 0.01), I2 = 0%. ORS administration caused no significant difference in gastric volume – 4 studies, 486 participants, MD -1.12 ml (95% CI -5.61 to 3.36), I2 = 62%, or gastric pH – 4 studies, 486 participants, MD -0.03. (95% CI -0.37 to 0.31), I2 = 0%, compared to the control group. On the other hand, ORS resulted in a significant reduction in SVV during the anesthesia induction period – 3 studies, 118 participants, MD -3.02 (95% CI -5.44 to -0.59), I2 = 65%.

Hence, the results suggested that oral rehydration therapy does not increase the risk of aspiration or vomiting. Whereas, it can help in stabilizing circulatory dynamics during anesthesia induction.

Source: Journal of Clinical Anesthesia. 2018 Sep;49:7-11. doi: 10.1016/j.jclinane.2018.05.015.