Robert K. Williams

Apnea after Awake Regional and General Anesthesia in Infants: The General Anesthesia Compared to Spinal Anesthesia Study-Comparing Apnea and Neurodevelopmental Outcomes, a Randomized Controlled Trial

Background:Postoperative apnea is a complication in young infants. Awake regional anesthesia (RA) may reduce the risk; however, the evidence is weak. The General Anesthesia compared to Spinal anesthesia study is a randomized, controlled trial designed to assess the influence of general anesthesia (GA) on neurodevelopment. A secondary aim is to compare rates of apnea after anesthesia. Methods:Infants aged 60 weeks or younger, postmenstrual age scheduled for inguinal herniorrhaphy, were randomized to RA or GA. Exclusion criteria included risk factors for adverse neurodevelopmental outcome and infants born less than 26 weeks gestation. The primary outcome of this analysis was any observed apnea up to 12 h postoperatively. Apnea assessment was unblinded. Results:Three hundred sixty-three patients were assigned to RA and 359 to GA. Overall, the incidence of apnea (0 to 12 h) was similar between arms (3% in RA and 4% in GA arms; odds ratio [OR], 0.63; 95% CI, 0.31 to 1.30, P = 0.2133); however, the incidence of early apnea (0 to 30 min) was lower in the RA arm (1 vs. 3%; OR, 0.20; 95% CI, 0.05 to 0.91; P = 0.0367). The incidence of late apnea (30 min to 12 h) was 2% in both RA and GA arms (OR, 1.17; 95% CI, 0.41 to 3.33; P = 0.7688). The strongest predictor of apnea was prematurity (OR, 21.87; 95% CI, 4.38 to 109.24), and 96% of infants with apnea were premature. Conclusions:RA in infants undergoing inguinal herniorrhaphy reduces apnea in the early postoperative period. Cardiorespiratory monitoring should be used for all ex-premature infants.

Speeds Associated With Skiing and Snowboarding

Abstract Category 1 Continuing Medical Education credit for WMS member physicians is available for this article. Go to http://wms.org/cme/cme.asp?whatarticle=1823 to access the test questions. Background/Objective.—Traumatic brain injury (TBI) is an important cause of morbidity and mortality in skiing and snowboarding. Although previous studies have advocated the use of a helmet to reduce the incidence of TBI, only a minority of skiers and snowboarders wear helmets. The low use of helmets may be partially due to controversy regarding their effectiveness in a high-speed crash. The protective effect of a ski helmet is diminished at the high speeds a skier or snowboarder can potentially obtain on an open slope. However, ski areas have undergone significant changes in the past decade. Many skiers and snowboarders frequent nontraditional terrain such as gladed areas and terrain parks. Since these areas contain numerous physical obstacles, we hypothesized that skiers and snowboarders would traverse these areas at speeds slow enough to expect a significant protective effect from a helmet. Methods.—Speed data were obtained via radar analysis of 2 groups of expert level skiers and snowboarders traversing a gladed woods trail and terrain park. Results.—A total of 113 observations were recorded. Forty-eight observations were made of 9 skiers and snowboarders in gladed terrain, and 65 observations were conducted of 21 skiers and snowboarders in the terrain park. In 79% of the cases in gladed terrain and 94% of the instances in the terrain park, observed speeds were less than 15 mph. Conclusions.—Skiers and snowboarders navigate nontraditional terrain at speeds slower than on open slopes. At the observed velocities, a helmet would be expected to provide significant help in diminishing the occurrence of TBI. Medical authorities should advocate the use of helmets as an important component of an overall strategy to reduce the incidence of TBI associated with skiing and snowboarding.

Cognitive outcome after spinal anesthesia and surgery during infancy.

BACKGROUND:Observational studies on pediatric anesthesia neurotoxicity have been unable to distinguish long-term effects of general anesthesia (GA) from factors associated with the need for surgery. A recent study on elementary school children who had received a single GA during the first year of life demonstrated an association in otherwise healthy children between the duration of anesthesia and diminished test scores and also revealed a subgroup of children with “very poor academic achievement” (VPAA), scoring below the fifth percentile on standardized testing. Analysis of postoperative cognitive function in a similar cohort of children anesthetized with an alternative to GA may help to begin to separate the effects of anesthesia from other confounders. METHODS:We used a novel methodology to construct a combined medical and educational database to search for these effects in a similar cohort of children receiving spinal anesthesia (SA) for the same procedures. We compared former patients with a control population of students matched by grade, gender, year of testing, and socioeconomic status. RESULTS:Vermont Department of Education records were analyzed for 265 students who had a single exposure to SA during infancy for circumcision, pyloromyotomy, or inguinal hernia repair. Exposure to SA and surgery had no significant effect on the odds of children having VPAA. (mathematics: P = 0.18; odds ratio 1.50, confidence interval (CI), 0.83–2.68; reading: P = 0.55; odds ratio = 1.19, CI, 0.67–2.1). There was no relationship between duration of exposure to SA and surgery and performance on mathematics (P = 0.73) or reading (P = 0.57) standardized testing. There was a small but statistically significant decrease in reading and math scores in the exposed group (mathematics: P = 0.03; reading: P = 0.02). CONCLUSIONS:We found no link between duration of surgery with infant SA and scores on academic achievement testing in elementary school. We also found no relationship between infant SA and surgery with VPAA on elementary school testing, although the CIs were wide.

Predictors of Failure of Awake Regional Anesthesia for Neonatal Hernia Repair: Data from the General Anesthesia Compared to Spinal Anesthesia Study-Comparing Apnea and Neurodevelopmental Outcomes

Background:Awake regional anesthesia (RA) is a viable alternative to general anesthesia (GA) for infants undergoing lower abdominal surgery. Benefits include lower incidence of postoperative apnea and avoidance of anesthetic agents that may increase neuroapoptosis and worsen neurocognitive outcomes. The General Anesthesia compared to Spinal anesthesia study compares neurodevelopmental outcomes after awake RA or GA in otherwise healthy infants. The aim of the study is to describe success and failure rates of RA and report factors associated with failure. Methods:This was a nested cohort study within a prospective, randomized, controlled, observer-blind, equivalence trial. Seven hundred twenty-two infants 60 weeks or less postmenstrual age scheduled for herniorrhaphy under anesthesia were randomly assigned to receive RA (spinal, caudal epidural, or combined spinal caudal anesthetic) or GA with sevoflurane. The data of 339 infants, where spinal or combined spinal caudal anesthetic was attempted, were analyzed. Possible predictors of failure were assessed including patient factors, technique, experience of site and anesthetist, and type of local anesthetic. Results:RA was sufficient for the completion of surgery in 83.2% of patients. Spinal anesthesia was successful in 86.9% of cases and combined spinal caudal anesthetic in 76.1%. Thirty-four patients required conversion to GA, and an additional 23 patients (6.8%) required brief sedation. Bloody tap on the first attempt at lumbar puncture was the only risk factor significantly associated with block failure (odds ratio = 2.46). Conclusions:The failure rate of spinal anesthesia was low. Variability in application of combined spinal caudal anesthetic limited attempts to compare the success of this technique to spinal alone.

Adverse Events and Resource Utilization After Spinal and General Anesthesia in Infants Undergoing Pyloromyotomy.

Background and Objectives Interest in spinal anesthesia (SA) is increasing because of concern about the long-term effects of intravenous (IV) and inhaled anesthetics in young children. This study compared SA versus general anesthesia (GA) in infants undergoing pyloromyotomy. Methods Between 2000 to 2013, the University of Vermont Medical Center almost exclusively used SA for infant pyloromyotomy surgery, whereas Columbia University Medical Center relied on GA. Outcomes included adverse events (AEs) within 48 hours of surgery, operating room (OR) time, and postoperative length of stay (LOS). Regression was used to evaluate the association between anesthesia technique and outcomes, accounting for demographic and clinical covariates. Results We studied 218 infants with SA at the University of Vermont Medical Center and 206 infants with GA at Columbia University Medical Center. In the SA group, 96.3% of infants had adequate initial analgesic levels, but 35.8% required supplemental IV or inhaled anesthetic agents. Compared with GA, the risk of AEs in SA (adjusted odds ratio, 0.60; 95% confidence interval [CI], 0.27–1.36) did not significantly differ, but SA was associated with shorter OR times (17.5 minutes faster; 95% CI, 13.5–21.4 minutes) and shorter postoperative LOS (GA is 1.19 times longer; 95% CI, 1.01–1.40). Conclusions Infants undergoing pyloromyotomy with SA had shorter OR times and postoperative LOS, no significant differences in AE rates, and decreased exposure to IV and inhaled anesthetics, although SA infants often still required supplemental anesthetics. Whether these differences result in any long-term benefit is unclear; further studies are needed to determine the risk of rare AEs, such as aspiration.

Pediatric anesthesia and neurotoxicity: what the radiologist needs to know

The use of cross-sectional imaging in the pediatric population continues to rise, particularly the use of MRI. Limiting motion artifact requires cooperative subjects who do not move during imaging, so there has been an increase in the need for pediatric sedation or anesthesia. Over the last decade, concern has increased that exposure to anesthesia might be associated with long-term cognitive deficits. In this review we report current understanding of the effects of anesthesia on the pediatric population, with special focus on long-term developmental and cognitive outcomes, and suggest how radiologists can use new technologies or imaging strategies to mitigate or minimize these potential risks.

Neonatal Anesthesia Neurotoxicity: A Review for Cleft and Craniofacial Surgeons

There is growing evidence that the commonly used anesthetic agents cause some degree of damage to the early developing brain. The animal evidence for anesthetic neurotoxicity is compelling. Numerous confounders in human research prevent researchers from drawing definitive conclusions about the degree of risk. For every surgery, it should be assessed whether the benefits of an early surgical procedure justify a potential but unquantifiable risk of neurotoxicity of anesthetic agents. The timing and number of surgeries in our treatment protocols may need to be reevaluated to account for these potential risks.

While we wait.

The controversy over the potential neurotoxicity of anesthetic exposure in young children continues. A unique collaboration between academia and government is focusing on the fundamental question of whether an apparently uncomplicated anesthetic in a healthy child may lead to subsequent development of cognitive or behavioral issues. Despite the concerted effort of numerous investigators, it is unlikely that this question will be resolved for a number of years. Even then, good science may still struggle to trump public perception, as evidenced by the purported link between autism and childhood immunizations. The case for anesthetic agents causing impaired learning in animals is compelling. The earliest rodent work has been replicated by numerous investigators, implicating most IV and volatile anesthetics in clinically relevant doses administered for plausible durations. Confirmatory primate studies have moved the debate one step closer to humans. However, the clinical implications of these animal studies for humans remain controversial. Epidemiological studies have demonstrated an association between general anesthesia in young children and the later diagnosis of learning disabilities, developmental disorders, or deficient performance on standardized tests. Unfortunately, it has proven difficult to isolate potential neurotoxic effects of anesthetic agents from other confounders. Prospective human studies are underway to determine whether general anesthesia in young children causes, and is not merely associated with, learning disabilities. However, because of the time required for patient recruitment and the later development of learning disabilities, it will require years for results to be available. Even then, these studies may be inconclusive. It seems that the effect of anesthetic agents may be relatively weak and appreciable only after multiple or prolonged exposures. Consequently, studies that examine the effect of a single anesthetic exposure may have insufficient power to exonerate anesthetic agents from neurotoxic effects. Identifying a cohort for a prospective human study involving multiple exposures to general anesthesia seems to be impractical. Therefore, we are likely to be considering this dilemma for many years to come. While we wait for the controversy to be settled, what should we do as a profession? A suggestion that surgical procedures should be “. . . delayed until a later age without incurring additional clinical risk” seems reasonable. However, because the majority of pediatric surgical cases are nonelective, it is unclear how much of an impact this would have. When surgery is required, is there more that anesthesiologists can do to mitigate any potential adverse effects of anesthetics without compromising the standard of care we have established? One editorial argued that there is no need for a change in practice based on animal data. However, perhaps it has come time for a shift in practice. What might this shift in practice look like? With regard to general anesthesia, both animal work and epidemiological evidence suggest that there is a dose-response curve with the agents of concern. When general anesthesia is required, should we examine whether we can deliver an appropriate level of anesthesia and analgesia while decreasing the use of suspect agents? This might be done by increasing the use of opioids, -2 drugs, and non-narcotic analgesics including ketorolac and paracetamol. Because these drugs have their own risk-benefit profiles, clinical trials should determine whether the anesthetic-sparing effect of these adjuvants is truly significant. What role can regional anesthesia play in this dilemma? Regional anesthesia is remarkably effective in young children and seems to be free of concerns regarding neurotoxicity and, indeed, the ongoing GAS study utilizes spinal anesthesia as its control to examine the incidence of anesthetic-induced neurotoxicity. When combined with general anesthesia, regional techniques can dramatically reduce the need for volatile anesthetics. Is there meaningful value in aggressively utilizing supplemental peripheral nerve blocks and neuraxial techniques and consequently decreasing exposure to volatile and IV anesthetics? Finally, should we be more receptive to using spinal or caudal anesthesia as a primary technique, thereby completely avoiding exposure to general anesthesia whenever possible? Although it is most frequently associated with repair of inguinal hernia in former premature infants, a wide variety of procedures have been successfully performed under infant spinal anesthesia including pyloromyotomy, lower extremity orthopedic surgery, cardiac catheterization, and major abdominal surgery. Spinal anesthesia in infants has a number of benefits including a decreased incidence of hypoxemia, hypotension, bradycardia, and postoperative apnea compared with general anesthesia. In this context, any potential decrease in even a perceived risk of From the Department of Anesthesiology, University of Vermont, Burlington, Vermont.

Spinal anesthesia in infants

Spinal anesthesia is an extremely stable anesthetic in infants with minimal impact on cardiac and respiratory physiology. Initial reports centered on its use in minor surgical procedures such as inguinal hernia repair and circumcision. However, its applications have broadened considerably over the past decade. Spinal anesthesia has now been reported for use in major surgical procedures in neonates including upper abdominal and cardiac surgery. As experience with the technique spreads, its use will likely continue to increase. A limitation of spinal anesthesia in this ge group is its relatively brief duration of action and inability to provide analgesia into the postoperative period. Combined spinal and epidural techniques may be one solution to this problem.