Daily Anesthesiology Research Analysis

BACKGROUND: Children undergoing moderate to deep sedation for diagnostic and therapeutic procedures are susceptible to hypoxemia because of their anatomical and physiologic features. However, optimal oxygen administration methods are unclear. This study aimed to evaluate the efficacy of oxygen supplementation during sedation using either low-flow or high-flow nasal cannula. METHODS: This prospective, multicenter randomized controlled trial included children (younger than 18 yr) undergoing moderate to deep sedation. The participants were randomly assigned to three groups as follows: (1) control (no oxygen), (2) low-flow (2 to 6 l/min oxygen via nasal cannula), and (3) high-flow (oxygen administration via high-flow nasal cannula with a flow rate of 2 l/kg and 50% fraction of inspired oxygen). The primary outcome was hypoxemia incidence (saturation of peripheral oxygen, oxygen saturation measured by pulse oximetry 95% or less for more than 5 s). Secondary outcomes included oxygen saturation measured by pulse oximetry less than 90%, rescue interventions, and sedation-related complications. Between-group differences were compared using a logistic regression model. RESULTS: A total of 253 participants were randomized, with 250 completing the study. Hypoxemia occurred in 27.6% of participants in the control group, 7.2% in the low-flow group, and 1.2% in the high-flow group ( P < 0.001). The odds of hypoxemia in the low-flow and high-flow groups were lower than that in the control group (odds ratio [OR], 0.184; 95% CI, 0.067 to 0.503; P = 0.001 for low-flow; OR, 0.026; 95% CI, 0.003 to 0.207; P < 0.001 for high-flow). However, hypoxemia incidence of the high-flow group was not statistically lower than the low-flow group (OR, 0.143; 95% CI, 0.017 to 1.245; P = 0.078). Rescue interventions were conducted more frequently in the control group (52.9%) than in the low-flow (10.8%) and high-flow (3.6%) groups ( P < 0.001). Sedation-related complications such as desaturation and apnea were lower in the low-flow and high-flow groups than in the control group ( P < 0.001). CONCLUSIONS: Routine oxygen supplementation prevents hypoxemia during pediatric moderate and deep sedation. Low-flow oxygen can be a reasonable choice as it effectively reduces hypoxemia while being more cost-effective and widely accessible than high-flow oxygen.

PURPOSE: Clinical trials often report medians and quartiles due to skewed data distributions. We sought to evaluate the methods currently used in meta-analyses in anesthesiology to estimate means and standard deviations (SDs) from medians and quartiles. METHODS: We simulated sample sizes (n = 15, 27, 51) and coefficients of variation (CV = 0.15, 0.3, 0.5), representative scenarios in anesthesiology studies, generating data that have a log-normal distribution with zero log-scale means. We calculated generalized confidence intervals for the ratios of means and ratios of SDs using means and SDs estimated from three quartiles in time scale, using Luo et al.'s and Wan et al.'s methods, McGrath et al.'s quantile estimation and Box-Cox transformation, and Cai et al.'s maximum likelihood estimation method. RESULTS: The method by Luo et al. and Wan et al. produced 95% confidence intervals for the ratio of means with coverage ranging from 92.4% to 93.6%, and for SDs from 79.2 to 89.6. McGrath et al.'s quantile estimation method yielded coverage for mean ratios between 88.5% and 91.5% and SDs between 78.0 and 82.7. McGrath et al.'s Box-Cox transformation method showed coverage for mean ratios from 86.6% to 94.4% and SDs from 67.1 to 83.1. The maximum likelihood estimation method by Cai et al. for nonnormal distributions showed coverage for mean ratios from 78.9% to 86.4% and SDs from 67.6 to 78.0. CONCLUSIONS: All evaluated methods of estimating means and standard deviations from quartiles of log-normal distributed data result in confidence interval coverages below the expected 95%. Because these methods are widely used in meta-analyses of anesthesiology data, P values reported as < 0.05 cannot be trusted. Anesthesiology journals and investigators should revise reporting requirements for continuous skewed variables. We advise reporting the quartiles, mean, and SD, or the quartiles and including the raw data for the relevant variables as supplemental content. This holistic approach could improve the reliability of statistical inferences in meta-analyses of anesthesiology research, particularly when skewed distributions are involved.

BACKGROUND: Postpartum hemorrhage (PPH) is the leading preventable cause of maternal mortality. Most PPH cases are caused by uterine atony, which is inconsistently defined in clinical care. The electronic health record was used to prompt communication between the anesthesia and obstetric care teams about uterine tone using a validated 11-point numeric rating scale (NRS) at 0, 5, and 10 min after placental delivery for all cesarean deliveries at our institution. The primary hypothesis was that lower uterine tone NRS would be strongly associated with progression to major PPH. METHODS: This was a single-center, prospective observational study conducted over a 1-yr period. The primary predictor was the 0 to 10 uterine tone NRS recorded 10 min after placental delivery, and the primary outcome was major PPH, defined as quantitative blood loss greater than or equal to 1,500 ml. Area under the receiver operating characteristic curves were created, and the relative risk of major PPH for each 1-point change in the tone score was estimated. Key secondary outcomes analyzed included associations between tone scores, PPH, and blood transfusion. RESULTS: A total of 1,599 consecutive cesarean deliveries were performed by obstetricians from academic (39.3%), county public health (21.1%), and private practice (38.8%) services. Major PPH complicated 9.9% and transfusion 6.7% of cesarean deliveries. Uterine tone NRS was documented at 0 min after placental delivery in 91.6%, 5 min in 97.4%, and 10 min in 97.0% of cesarean deliveries. The 10-min NRS was a strong predictor of major PPH, with an area under the receiver operating characteristic of 0.78 (95% CI, 0.73 to 0.82). Each 1-point decrease in NRS increased the risk of major PPH by 71% (95% CI, 0.58 to 0.86). A 10-min uterine tone NRS less than or equal to 6 had high positive predictive value for major PPH (32.9%), as well as PPH (64.2%) and transfusion (20.6%). CONCLUSIONS: Standardized uterine tone assessments on a 0 to 10 scale are feasible to implement and strongly associated with progression to major PPH and blood transfusion. Future studies should investigate whether implementation of PPH interventions based on uterine tone NRS can reduce major PPH and hemorrhage-associated morbidity.