C. Keith Stone

The effectiveness of esophageal stethoscopy in a simulated in-flight setting☆

PURPOSE Previous research has confirmed the inability of flight nurses in an airborne BO-105 helicopter to hear breath sounds using normal or amplified transthoracic stethoscopy. The purpose of this study was to determine whether esophageal stethoscopy enabled effective auscultation of breath sounds in a simulated in-flight environment. METHODS The cabin-sound environment of an in-flight BO-105 was recorded and recreated in an audiology laboratory, where five flight nurses were evaluated listening to taped breath sounds via an esophageal stethoscope. This audiotape model, validated in a previously published study, used a tape consisting of 24 20-second segments. Each segment, the beginning of which was marked with a beep signal, consisted of 20 seconds of silence or breath sounds. The distal (esophageal) end of the esophageal stethoscope was attached to the tape recorder; the intensity level of breath sounds heard at the stethoscope earpiece was calibrated to equate the sound level of actual esophageal breath sounds recorded on a volunteer. RESULTS All nurses correctly identified the 24 taped segments as silent or including breath sounds 100% of the time. CONCLUSION In the simulated environment tested, esophageal stethoscopy enabled 100% accuracy in identification of breath sounds, as compared with previously reported 0% efficacy for standard transthoracic auscultation. Study in the actual patient-care environment is indicated to confirm the usefulness of esophageal stethoscopy in the in-flight setting.

Air vs ground transport and outcome in trauma patients requiring urgent operative interventions

OBJECTIVE To study trauma patients requiring urgent operative interventions to determine whether transport mode was associated with outcome difference. METHODS Eligible patients were injured adults and children who presented over a 57-month period to the emergency department (ED) at the study hospital (annual ED census 36,000) after air or ground transport from trauma scenes or referring hospitals. Patients included were those whose ED lengths of stay were <60 minutes prior to transfer to an operating room. Data collected included injury severity score (ISS), ED and hospital lengths of stay, and mortality. Continuous data, which were not distributed normally, were analyzed using Wilcoxon nonparametric analysis. Categorical variables were analyzed using chi-square testing. Multivariate logistic regression was used to account for confounding variables and isolate the effects of transport mode on mortality. Alpha for all tests was set at 0.05. RESULTS 272 patients were eligible for study; 168 air medical and 104 ground transports. No between-group differences were found for ED length of stay, ISS, or mortality. A significantly longer hospital stay was found for air-transported patients. Subgroup analysis of patients with penetrating trauma and ISS of > or =25 revealed mortalities of 28% and 45% for air- and ground-transported patients, respectively; this difference was not statistically significant (p = 0.24), but the study had a power of only 22% to detect a difference at this magnitude. CONCLUSION This study failed to identify, but had insufficient power to rule out, outcome benefit to air medical transport in a subset of trauma patients requiring urgent operative interventions.

Airway management in the air medical setting

Abstract Research into air medical team airway management practice has answered many questions and demonstrated the ability of flight crews to manage even the most difficult airways effectively. Further study in air medicine will continue to refine airway management protocols to result in maximum safety and efficacy for air-transported patients.

Red cabin lights impair air medical crew performance of color-dependent tasks

INTRODUCTION Red cabin lighting is often used for nighttime patient transports in helicopters. This study was conducted to determine if red lighting results in impairment of color-dependent tasks. METHODS An emergency medical services pilot adjusted red lighting in a BO-105 cabin to maximum acceptable intensity. Thirteen emergency room residents were shown positive and negative CO2 detectors and skin-colored and cyan-tinted rubber masks; percentages of correctly identified masks and detectors were noted. Subjects also read drug name and amount from 12 medication labels. Wilcoxon analysis (p = 0.05) was used to compare label reading accuracy between two groups: control (black/white lettering/background) and red (red lettering or background). RESULTS Percentages of accurately identified masks and detectors in the red light setting were as follows: normal mask 61.5%, cyanotic mask 30.8%, negative and positive CO2 detectors 46.2%. Ability to correctly read medication labeling was significantly (p = 0.003) greater in control (76.9 +/- 10.9%) as compared to red groups (16.3 +/- 13.4%). CONCLUSION Red cabin lighting appears to impair performance of certain critical tasks requiring color discernment. Consideration of this by medical crews working under red light conditions could reduce risk for patient-care errors.