A Randomized Controlled Trial to Determine the Effect of Depth of Anesthesia on Emergence Agitation in Children.

BACKGROUND: The cause of emergence agitation (EA) in children is unknown. Rapid emergence from inhaled anesthesia has been implicated because EA is more common with sevoflurane than with halothane. A dose-dependent effect of sevoflurane, which increases seizure-like electroencephalogram activity, has also been proposed. METHODS: To determine whether depth of anesthesia as measured by bispectral index (BIS) affects EA, 40 ASA physical status I to II children aged 2 to 8 years undergoing ophthalmic surgery were enrolled in a blinded randomized controlled trial of low-normal (40-45, deep) versus high-normal (55-60, light) anesthesia. To distinguish transient irritability from severe EA, the primary outcome was first-stage postanesthesia care unit (PACU I) peak Pediatric Assessment of Emergence Delirium (PAED) score, with secondary outcomes of PAED and Face, Legs, Activity, Cry, and Consolability scores at emergence, postoperative fentanyl dose, emergence time, and discharge time. Subjects received a standard anesthesia protocol with oral midazolam followed by mask induction with sevoflurane 8%, fentanyl 1 to 1.5 µg/kg IV (then as needed), neuromuscular blockade, and endotracheal intubation. Providers titrated expired sevoflurane (in N2O 67%) from 0.5% to 3% to maintain BIS range. PAED, Richmond Agitation Sedation Scale, and Face, Legs, Activity, Cry, and Consolability scores were measured at emergence, at PACU I arrival, and during PACU I stay. RESULTS: There was little difference between the groups in the primary outcome, peak PACU I PAED score (light: 7.7 ± 4.6; deep: 8.6 ± 5.3; mean difference, 0.9; 95% confidence interval, 4.1 to -2.3; effect size, 0.18). Discharge times were similar between groups. Treatment for severe EA was rare. CONCLUSIONS: There was no significant effect of BIS-guided deep versus light anesthesia on severe EA.

The "Simulation Roulette" game.

INTRODUCTION: "Simulation Roulette" is a new method of "on-the-fly" simulation scenario creation that incorporates a game-like approach to critical scenarios and emphasizes prescenario preparation. We designed it to complement our traditional anesthesia simulation curriculum, in which residents are exposed to predefined "critical" scenarios. During typical scenarios, trainees are often given minimum preparatory information; they then start the scenario knowing only that "something bad" is going to happen. As a result, trainees often report anxiety, which can be a barrier to learning. To overcome this barrier and to augment traditional critical incident training, we developed the "Simulation Roulette" game. METHODS: "Simulation Roulette" consists of premade cards that are randomly selected to create a patient, another set of premade cards to assist in selecting "complications," worksheets to guide a thorough "prebrief" discussion before the scenario, and scoresheets to facilitate the "debrief" discussion at the end. Similar to traditional scenarios, it requires coordination by a facilitator to ensure plausible scenarios and evaluation of trainee performance. RESULTS: Although we have not conducted formal testing, we believe that (1) incorporating an element of random chance to scenario selection, (2) using a game-like framework, and (3) emphasizing the "prebrief" portion of simulation all have the potential to decrease trainee anxiety. CONCLUSIONS: We present the rationale for designing such a game; examples of instructions, cards, and scoresheets; and our initial experience with implementing this game within our simulation curriculum.

The independently fractal nature of respiration and heart rate during exercise under normobaric and hyperbaric conditions.

To test the hypothesis that the fractal character of breathing and heart rate are independent, inter-breath intervals (IBI) and R-R intervals (RRI) were measured during rest and two levels of exercise at 1 and 2.8 ATA in a hyperbaric chamber in 18 male and female subjects (ages 19-74 years). Both RRI and IBI showed fractal properties. Fractal dimensions (D) for IBI were (mean +/- S.D.) 1.33 +/- 0.11, 1.29 +/- 0.12, 1.19 +/- 0.16 (rest, light and heavy exercise at 1ATA); 1.33 +/- 0.13, 1.25 +/- 0.13, 1.18 +/- 0.14 (same conditions at 2.8 ATA). Corresponding D for RRI were 1.19 +/- 0.11, 1.05 +/- 0.07 and 1.02 +/- 0.05 (1ATA); 1.20 +/- 0.10, 1.03 +/- 0.04 and 1.01 +/- 0.02 (2.8 ATA). The fractal dimension of each variable decreased with exercise and was unaffected by hyperbaric exposure. These two systems were not cross-correlated under any of the six conditions. During rest and light and moderate exercise at 1 and 2.8 ATA the results are consistent with heart rate variability and breathing rate variability being mutually independent of one another.