Discussion
nausea or vomiting, ®, vomiting, dehydration, hypotension, gastroesophageal sphincter
COMPLICATIONS, UTERUS, DEHYDRATION, SAID, INSULIN RESISTANCE, DELAYED GASTRIC EMPTYING
In this prospective randomized study of 51 parturients undergoing scheduled cesarean section, we found that PORT with OS-1® reduced the number of vasopressor boluses and phenylephrine doses during surgery compared with the fasting group. In addition, gastric emptying in healthy parturients was not delayed after drinking 500 mL of clear fluid 2 h before cesarean section compared to that in the fasting group. Similarly, a previous study concluded that PORT prevents hypotension after spinal anesthesia induction [In this study, we used OS-1®, which meets the oral rehydration therapy guidelines recommended by the World Health Organization and is a balanced mixture of water, glucose, and electrolytes [Generally, parturients are at an increased risk of anesthesia aspiration. An increase in the intragastric pressure due to the gravid uterus, a relaxed gastroesophageal sphincter due to the increased progesterone level, and delayed gastric emptying during pregnancy contribute to the risk. For this reason, although recent guidelines recommend the intake of clear liquids at least 2 h before elective surgery, [Regarding the safety of PORT, we found that as the ORS is highly absorbable and has a short stagnation time in the stomach, ultrasound assessment of the gastric antral CSA in parturients did not increase. There was no apparent or potential risk of aspiration, vomiting, or other drink-related complications before, during, or after surgery. Therefore, we confirmed, by ultrasound, that 500 mL of ORS 2 h before surgery could be acceptable in parturients undergoing cesarean section under spinal anesthesia.Preoperative infusion is said to be equally effective for the prevention of dehydration during the induction of anesthesia [In the present study, the ORS group showed significant differences from the fasting group in regards to the suppression of circulatory changes; however, ORS and mineral water did not show significant differences. Regarding excretion from the stomach, water and ORS were excreted at rates similar to those in previous studies on healthy adults. Thus, ORS is well excreted from the stomach; in addition, previous research has shown that ORS can correct electrolytes and reduce insulin resistance [Nonetheless, our study has some potential limitations. First, as it was impossible to obtain informed consent for emergent cesarean section because of the study protocol; all participants had scheduled elective cesarean sections. We also did not include parturients with complications or ASA physical status class ≥ III. This may limit the generalizability of our conclusions to more severe cases. Accordingly, further studies are needed to confirm whether the results would differ in such cases. Second, it was not a blinded clinical trial because of the taste of the drink, which may have increased the bias. However, the data were analyzed by a study investigator who was not involved in providing anesthesia. Third, although preoperative drinking could cause perioperative nausea or vomiting, this effect was not examined in the present study and is an issue for future research. Finally, sonographic gastric examination is often difficult, especially because pregnancy increases the technical difficulty.