Efficacy of gastric aspiration in reducing posttonsillectomy vomiting.

OBJECTIVE: To determine the effectiveness of postoperative gastric decompression in reducing the incidence and complications associated with vomiting following tonsillectomy. DESIGN: A prospective, randomized controlled study. SETTING: Private office and clinic of a university teaching hospital and research center. PATIENTS: Eighty pediatric patients ranging in age from 22 months to 11 years, American Society of Anesthesiologists class I or II, undergoing tonsillectomy with or without adenoidectomy were enrolled in the study. Six were excluded from the final analysis, 5 because of failure of the parents to complete and return the data forms and 1 because of postoperative bleeding. Of the 74 patients included in the study, 35 were in the control group and 39 were in the study group. INTERVENTIONS: The 39 patients in the study group underwent postoperative aspiration of gastric contents with an orogastric tube placed under direct visualization while the patient was still under general anesthesia. The 35 patients in the control group did not undergo gastric aspiration following surgery. MAIN OUTCOME MEASURES: The incidence of vomiting, the number of episodes of vomiting before and after hospital discharge, the total volume of emesis, the postoperative length of stay, the need for rescue antiemetic prophylaxis, and the number of readmissions to the hospital for persistent vomiting were noted. RESULTS: No statistically significant difference (P<.05) was noted between the control group and the study group for the percentage of patients experiencing vomiting (74% vs 85%), the mean number of episodes of vomiting before (2.6 vs 2.8) and after (0.8 vs 0.7) hospital discharge, the mean volume of emesis (157 mL vs 222 mL), the postoperative length of stay (394 minutes vs 334 minutes), the percentage of patients requiring rescue antiemetics (34% [12 patients] vs 33% [13 patients]), and the percentage of unplanned admissions because of vomiting (9% [3 patients] vs 15% [6 patients]). CONCLUSION: Our results indicate that gastric aspiration does not decrease the incidence of vomiting following tonsillectomy.

Analgesia, pruritus, and ventilation exhibit a dose-response relationship in parturients receiving intrathecal fentanyl during labor.

UNLABELLED: Several studies have characterized the 50% and 95% effective doses (ED50 and ED95, respectively) of intrathecal sufentanil for labor analgesia. Few have investigated these same criteria for the less expensive alternative, fentanyl. In addition, the ventilatory effects of intrathecal fentanyl at clinically relevant doses are unclear. We performed this study to establish the dose-response relationship of intrathecal fentanyl for both analgesia and ventilatory depression. Ninety parturients in active early labor (< or = 5 cm dilation) received intrathecal fentanyl 5, 7.5, 10, 15, 20, or 25 micrograms in a double-blinded, randomized fashion (n = 15 patients in each group). Parturients were monitored for degree of pain (measured using a 100-mm visual analog pain scale), blood pressure, arterial oxygen saturation (SaO2), respiratory rate, ETCO2, and fetal heart rate 0, 1, 5, 10, 15, 20, 25, and 30 min after the administration of intrathecal fentanyl. An absolute visual analog pain scale score < or = 25 mm was defined a priori as analgesic success. The percentage of parturients who achieved analgesic success was used to construct quantal dose-response curves, from which the ED50 and ED95 values were derived for the total population (mixed parity) and the nulliparous and multiparous subpopulations separately. Overall ED50 and ED95 values (95% CI) were 5.5 (3.4-7.2) and 17.4 (13.8-27.1) micrograms, respectively. Nulliparous values were lower (5.3 and 15.9 micrograms, respectively) than multiparous values (6.9 and 26.0 micrograms, respectively) but were within the 95% CIs of the total population. Pruritus incidence in parturients with analgesic success displayed a dose-response relationship identical to that seen for analgesia. ETCO2 displayed a dose-related increase, particularly at doses > or = 15 micrograms, without concomitant changes in respiratory rate or SaO2, which suggests a decrease in tidal volume. Even in the absence of overt signs or symptoms of somnolence, intrathecal fentanyl at doses within the effective analgesic range induced a change in ventilation that may last longer than the 30-min period we studied. IMPLICATIONS: Intrathecal fentanyl induces rapid and satisfying dose-dependent analgesia in early labor; however, it also produces dose-related decreases in ventilation in the absence of overt somnolence.

Prevention of maternal hypotension by epidural administration of ephedrine sulfate during lumbar epidural anesthesia for cesarean section.

OBJECTIVE: Our purpose was to determine whether epidural administration of ephedrine sulfate simultaneously with induction of lumbar epidural anesthesia for nonemergency cesarean section reduces the incidence of maternal hypotension. STUDY DESIGN: In a double-blinded, placebo-controlled trial, 50 normotensive, nonlaboring, American Society of Anesthesiologists' class I or II women with term, uncomplicated, singleton pregnancies were randomly assigned to have normal saline solution or ephedrine sulfate administered epidurally and coincidentally with induction of lumbar epidural anesthesia for nonemergency cesarean section. All subjects were prehydrated with 25 ml/kg crystalloid and placed in supine position on a 15-degree, right-sided wedge before and after induction. Serial blood pressures were compared with baseline blood pressures, chosen as the average of three preinduction blood pressures. Hypotension was defined as a decline in systolic blood pressure to < or = 90 mm Hg or < or = 70% of baseline. Differences between groups were analyzed by Fisher's Exact Test. Significance was determined at p < 0.05. RESULTS: The incidence of hypotension in the control group was 24%, which was not significantly different from the incidence of 32% in the treated group. CONCLUSION: Prophylactic epidural administration of ephedrine sulfate does not reduce the incidence of maternal hypotension after lumbar epidural anesthesia for nonemergency cesarean section.

Baseline serum and cerebrospinal fluid magnesium levels in normal pregnancy and preeclampsia.

OBJECTIVE: To determine whether baseline cerebrospinal fluid magnesium levels in preeclampsia differ from those in normal pregnancy, and to ascertain whether pre-treatment cerebrospinal fluid magnesium levels correlate with serum levels, which would suggest a baseline alteration in the blood-brain barrier in preeclampsia. METHODS: When spinal analgesia or anesthesia was administered for delivery, serum and cerebrospinal fluid magnesium levels were determined in 20 normal gravidas and 20 preeclamptic women not treated with magnesium sulfate. Data were analyzed by two-sided Student t test and regression analysis. RESULTS: Mean (+/- standard deviation) cerebrospinal fluid magnesium level for preeclamptic patients was 2.23 +/- 0.09 mEq/L, which was not significantly different from controls. Regression analysis revealed no significant correlation between cerebrospinal fluid and serum magnesium levels for either normal or preeclamptic gravidas. CONCLUSION: During the third trimester, there is no difference in baseline, pre-treatment cerebrospinal fluid magnesium levels in preeclamptic patients compared to normal subjects, and no correlation between cerebrospinal fluid and serum magnesium over the range of baseline values.