Stimulation of the P6 Acupuncture Point for Prophylaxis of Nausea and Vomiting in Pregnant Women Submitted to Cesarean Section: A Blinded Clinical Trial

In pregnant women subjected to spinal anesthesia for a Cesarean section, episodes of nausea and vomiting are common both during and following surgery. Acupuncture for the prophylaxis and treatment of these complications has been gaining in popularity due to its low cost, simplicity, absence of side effects and confirmed efficacy. This study investigated the efficacy of stimulating the P6 acupoint in conjunction with the use of dexamethasone as prophylaxis for nausea and vomiting in pregnant women submitted to spinal anesthesia for a Cesarean section. The patients (n = 100) were randomly distributed into two groups. In the first group (n = 50), a site located one centimeter laterally from P6 was stimulated. This is not a true acupuncture point (sham acupuncture). In the second group (n = 50), P6 was stimulated. In both groups, 4 mg of dexamethasone were administered intravenously. A questionnaire was used to obtain information on the occurrence of nausea and vomiting during surgery and in the first 12 hours postpartum. The chi-square test and Fisher’s exact test were used to assess differences between the groups. Age and physical status were similar in both groups. The incidence of nausea during surgery was 32% (n = 16) in the control group and 22% (n = 11) in the P6 group (p > 0.05). In the first 12 hours following surgery, nausea occurred in 16% of the women in the control group (n = 6) and in 4% in the P6 group (n = 4) (p = 0.045). The incidence of vomiting in the control group was 12% (n = 6) during surgery and 10% (n = 5) in the postoperative period compared to 8% (n = 4) and 4% (n = 2), respectively, in the P6 group (p > 0.05). Although these differences were not statistically significant with the exception of the incidence of nausea in the first 12 hours postpartum, a reduction occurred in the incidence of all the outcomes evaluated in the P6 group.

Clinical Criteria for Airway Assessment: Correlations with Laryngoscopy and Endotracheal Intubation Conditions

Difficult intubation, inadequate ventilation and esophageal intubation are the principal causes of death or brain damage related to airway manipulation. The objective of this cross-sectional study was to correlate a preanesthetic evaluation that may be capable of predicting a difficult intubation with the conditions encountered at laryngoscopy and endotracheal intubation. Eighty-one patients submitted to general anesthesia were evaluated at a preanesthetic consultation according to the modified Mallampati classification, the Wilson score and the American Society of Anesthesiologists (ASA) difficult airway algorithm. Findings were then correlated with the Cormack-Lehane classification and with the number of attempts at endotracheal intubation. No statistically significant correlations were found between the patients’ Mallampati classification and their Cormack-Lehane grade or between the Mallampati classification and the number of attempts required to achieve endotracheal intubation. Laryngoscopy proved difficult in four patients and in all of these cases the Wilson score had been indicative of a possibly difficult airway, highlighting its good predicting sensitivity. However, the specificity of this test was low, since another 24 patients had the same Wilson score but were classified as Cormack-Lehane I/II. Moreover, two patients who had a Wilson score ≥ 4 were also classified as Cormack-Lehane grade I/II. The study concluded that the Wilson score, although seldom used in clinical practice, is a highly sensitive predictor of a difficult airway;its specificity, however, is low.