Anesthesiology Resident Night Float Duty Alters Sleep Patterns: An Observational Study.

BACKGROUND: Residency programs utilize night float systems to adhere to duty hour restrictions; however, the influence of night float on resident sleep has not been described. The study aim was to determine the influence of night float on resident sleep patterns and quality of sleep. We hypothesized that total sleep time decreases during night float, increases as residents acclimate to night shift work, and returns to baseline during recovery. METHODS: This was a single-center observational study of 30 anesthesia residents scheduled to complete six consecutive night float shifts. Electroencephalography sleep patterns were recorded during baseline (three nights), night float (six nights), and recovery (three nights) using the ZMachine Insight monitor (General Sleep Corporation, USA). Total sleep time; light, deep, and rapid eye movement sleep; sleep efficiency; latency to persistent sleep; and wake after sleep onset were observed. RESULTS: Mean total sleep time ± SD was 5.9 ± 1.9 h (3.0 ± 1.2.1 h light; 1.4 ± 0.6 h deep; 1.6 ± 0.7 h rapid eye movement) at baseline. During night float, mean total sleep time was 4.5 ± 1.8 h (1.4-h decrease, 95% CI: 0.9 to 1.9, Cohen's d = -1.1, P < 0.001) with decreases in light (2.2 ± 1.1 h, 0.7-h decrease, 95% CI: 0.4 to 1.1, d = -1.0, P < 0.001), deep (1.1 ± 0.7 h, 0.3-h decrease, 95% CI: 0.1 to 0.4, d = -0.5, P = 0.005), and rapid eye movement sleep (1.2 ± 0.6 h, 0.4-h decrease, 95% CI: 0.3 to 0.6, d = -0.9, P < 0.001). Mean total sleep time during recovery was 5.4 ± 2.2 h, which did not differ significantly from baseline; however, deep (1.0 ± 0.6 h, 0.4-h decrease, 95% CI: 0.2 to 0.6, d = -0.6, P = 0.001 *, P = 0.001) and rapid eye movement sleep (1.2 ± 0.8 h, 0.4-h decrease, 95% CI: 0.2 to 0.6, d = -0.9, P < 0.001 P < 0.001) were significantly decreased. CONCLUSIONS: Electroencephalography monitoring demonstrates that sleep quantity is decreased during six consecutive night float shifts. A 3-day period of recovery is insufficient for restorative sleep (rapid eye movement and deep sleep) levels to return to baseline.

Generative retrieval results in positive academic emotions and long-term retention of cardiovascular anatomy using transthoracic echocardiography.

With increasing medical knowledge, procedural, and diagnostic skills to learn, it is vital for educators to make the limited amount of teaching time available to students effective and efficient. Generative retrieval is an effective and efficient learning tool, improving long-term retention through the practice of retrieval from memory. Forty medical students were randomized to learn normal cardiovascular anatomy using transthoracic echocardiography video clips in a generative retrieval (GR) or standard practice (SP) group. GR participants were required to verbally identify each unlabeled cardiovascular structure after viewing the video. After answering, participants viewed the correctly labeled video. SP participants viewed the same video clips labeled with the correct cardiovascular structure for the same amount of total time without verbally generating an answer. All participants were tested for intermediate (1-wk), late (1-mo), and long-term (6- to 9-mo) retention of cardiovascular anatomy. Additionally, a three-question survey was incorporated to assess perceptions of the learning method. There was no difference in pretest scores. The GR group demonstrated a trend toward improvement in recall at 1 wk [GR = 74.3 (SD 12.3); SP = 65.4 (SD 16.7); P = 0.10] and 1 mo [GR = 69.9 (SD15.6); SP = 64.3 (SD 15.4); P = 0.33]. At the 6- to 9-mo time point, there was a statistically significant difference in scores [GR = 74.3 (SD 9.9); SP = 65.0 (SD 14.1); P = 0.042]. At nearly every time point, learners had a statistically significantly higher perception of effectiveness, enjoyment, and satisfaction with GR. In addition to improved recall, GR is associated with increased perceptions of effectiveness, enjoyment, and satisfaction, which may lead to increased engagement, time spent studying, and improved retention.

Influence of Sex and Body Language on Patient Perceptions of Anesthesiologists.

BACKGROUND: Patient perception of physician competence is important. The role of body language and physician sex on patient perceptions has not been investigated. The authors hypothesized that patients perceive anesthesiologists displaying confident body language as more competent and that patients would prefer male anesthesiologists. METHODS: Two hundred adult patients presenting to the Preanesthesia Evaluation and Testing Center at the University of Virginia Health System were recruited to participate using consecutive sampling. Patients viewed four 90-s videos in random order. Each video featured a male or female actor displaying confident, high-power poses or unconfident, low-power poses. Each actor recited the same script describing general anesthesia. Patients were randomized (100 per group) to view one of two sets of videos to account for any actor preferences. Participants ranked each actor anesthesiologist on perceived confidence, intelligence, and likelihood of choosing that anesthesiologist to care for their family member. Participants also chose the one actor anesthesiologist who seemed most like a leader. RESULTS: Two hundred patients watched the videos and completed the questionnaire. Actor anesthesiologists displaying confident, high-power body language had greater odds of being ranked as more confident (odds ratio, 2.27; 95% CI, 1.76 to 2.92; P < 0.0001), more intelligent (odds ratio, 1.69; 95% CI, 1.13 to 2.18; P < 0.0001), more likely chosen to care for one's family member (odds ratio, 2.34; 95% CI, 1.82 to 3.02; P < 0.0001), and more likely to be considered a leader (odds ratio, 2.60; 95% CI, 1.86 to 3.65; P < 0.0001). Actor anesthesiologist sex was not associated with ranking for any response measures. CONCLUSIONS: Patients perceive anesthesiologists displaying confident body language as more confident, more intelligent, more like a leader, and are more likely to choose that anesthesiologist to care for their family member. Differences in patient perceptions based on sex of the anesthesiologist were not detected.

Generative Retrieval Does Not Improve Long-Term Retention of Regional Anesthesia Ultrasound Anatomy in Unengaged Learners.

BACKGROUND: Ultrasound-guided regional anesthesia is increasingly used in the perioperative period but performance requires a mastery of regional ultrasound anatomy. We aimed to study whether the use of generative retrieval to learn ultrasound anatomy would improve long-term recall. METHODS: Fourth-year medical students without prior training in ultrasound techniques were randomized into standard practice (SP) and generative retrieval (GR) groups. An initial pre-test consisted of 74 regional anesthesia ultrasound images testing common anatomic structures. During the study/learning session, GR participants were required to verbally identify an unlabeled anatomical structure within 10 seconds of the ultrasound image appearing on the screen. A labeled image of the structure was then shown to the GR participant for 5 seconds. SP participants viewed the same ultrasound images labeled with the correct anatomical structure for 15 seconds. Retention was tested at 1 week and 1 month following the study session. Participants completed a satisfaction survey after each session. RESULTS: Forty-five medical students were enrolled with forty included in the analysis. There was no statistically significant difference in baseline scores (GR = 11.5 ± 4.9; SP = 11.2 ± 6.2; P = 0.84). There was no difference in scores at both the 1-week (SP = 54.5 ± 13.3; GR = 53.9 ± 10.5; P = 0.88) and 1-month (SP = 54.0 ± 14.5; GR = 50.7 ± 11.1; P = 0.42) time points. There was no statistically significant difference in learner satisfaction metrics between the groups. CONCLUSIONS: The use of generative retrieval practice to learn regional anesthesia ultrasound anatomy did not yield significant differences in learning and retention compared with standard learning.

Hypercapnia in diving: a review of CO2 retention in submersed exercise at depth.

Carbon dioxide (CO2) retention, or hypercapnia, is a known risk of diving that can cause mental and physical impairments leading to life-threatening accidents. Often, such accidents occur due to elevated inspired carbon dioxide. For instance, in cases of CO2 elimination system failures during rebreather dives, elevated inspired partial pressure of carbon dioxide (PCO2) can rapidly lead to dangerous levels of hypercapnia. Elevations in PaCO2 (arterial pressure of PCO2) can also occur in divers without a change in inspired PCO2. In such cases, hypercapnia occurs due to alveolar hypoventilation. Several factors of the dive environment contribute to this effect through changes in minute ventilation and dead space. Predominantly, minute ventilation is reduced in diving due to changes in respiratory load and associated changes in respiratory control. Minute ventilation is further reduced by hyperoxic attenuation of chemosensitivity. Physiologic dead space is also increased due to elevated breathing gas density and to hyperoxia. The Haldane effect, a reduction in CO2 solubility in blood due to hyperoxia, may contribute indirectly to hypercapnia through an increase in mixed venous PCO2. In some individuals, low ventilatory response to hypercapnia may also contribute to carbon dioxide retention. This review outlines what is currently known about hypercapnia in diving, including its measurement, cause, mental and physical effects, and areas for future study.

Swimming-Induced Pulmonary Edema: Pathophysiology and Risk Reduction With Sildenafil.

BACKGROUND: Swimming-induced pulmonary edema (SIPE) occurs during swimming or scuba diving, often in young individuals with no predisposing conditions, and its pathophysiology is poorly understood. This study tested the hypothesis that pulmonary artery and pulmonary artery wedge pressures are higher in SIPE-susceptible individuals during submerged exercise than in the general population and are reduced by sildenafil. METHODS AND RESULTS: Ten study subjects with a history of SIPE (mean age, 41.6 years) and 20 control subjects (mean age, 36.2 years) were instrumented with radial artery and pulmonary artery catheters and performed moderate cycle ergometer exercise for 6 to 7 minutes while submersed in 20°C water. SIPE-susceptible subjects repeated the exercise 150 minutes after oral administration of 50 mg sildenafil. Work rate and mean arterial pressure during exercise were similar in controls and SIPE-susceptible subjects. Average o2 and cardiac output in controls and SIPE-susceptible subjects were: o2 2.42 L·min(-1) versus 1.95 L·min(-1), P=0.2; and cardiac output 17.9 L·min(-1) versus 13.8 L·min(-1), P=0.01. Accounting for differences in cardiac output between groups, mean pulmonary artery pressure at cardiac output=13.8 L·min(-1) was 22.5 mm Hg in controls versus 34.0 mm Hg in SIPE-susceptible subjects (P=0.004), and the corresponding pulmonary artery wedge pressure was 11.0 mm Hg versus 18.8 mm Hg (P=0.028). After sildenafil, there were no statistically significant differences in mean pulmonary artery pressure or pulmonary artery wedge pressure between SIPE-susceptible subjects and controls. CONCLUSIONS: These observations confirm that SIPE is a form of hemodynamic pulmonary edema. The reduction in pulmonary vascular pressures after sildenafil with no adverse effect on exercise hemodynamics suggests that it may be useful in SIPE prevention. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00815646.

Immersion pulmonary edema and comorbidities: case series and updated review.

PURPOSE: Immersion pulmonary edema (IPE) occurs in swimmers (especially triathletes) and scuba divers. Its pathophysiology and risk factors are incompletely understood. This study was designed to establish the prevalence of preexisting comorbidities in individuals who experience IPE. METHODS: From 2008 to May 2010, individuals who had experienced IPE were identified via recruitment for a physiological study. Past medical history and subject characteristics were compared with those available in the current body of literature. RESULTS: At Duke University Medical Center, Durham, NC, 36 subjects were identified (mean age = 50.11 ± 10.8 yr), of whom 72.2% had one or more significant medical conditions at the time of IPE incident (e.g., hypertension, cardiac dysrhythmias or structural abnormality or dysfunction, asthma, diabetes mellitus, overweight or obesity, obstructive sleep apnea, hypothyroidism). Forty-five articles were included, containing 292 cases of IPE, of which 24.0% had identifiable cardiopulmonary risk factors. Within the recreational population, cases with identifiable risk factors comprised 44.9%. Mean age was 47.8 ± 11.3 yr in recreational divers/swimmers and 23.3 ± 6.4 yr in military divers/swimmers. CONCLUSIONS: Cardiopulmonary disease may be a common predisposing factor in IPE in the recreational swimming/diving population, whereas pulmonary hypertension due to extreme exertion may be more important in military cases. Individuals with past history of IPE in our case series had a greater proportion of comorbidities compared to published cases. The role of underlying cardiopulmonary dysfunction may be underestimated, especially in older swimmers and divers. We conclude that an episode of IPE should prompt the evaluation of cardiac and pulmonary function.