Securing the airway by endotracheal intubation (ETI) is a key issue in prehospital critical care. Night vision goggles (NVG) are used by personnel operating in low-light environments. We examined the feasibility of an anesthesiologist performed ETI using NVG in a helicopter setting.
Twelve anesthesiologists performed ETI on a manikin in an emergency room (ER) setting and two helicopter settings, with randomization to either rotary wing daylight (RW-D) or rotary wing in total darkness using binocular NVG (RW-NVG). Primary endpoint was intubation time. Secondary endpoints included success rate, Cormack-Lehane (CL) score, and subjective difficulty according to the Visual Analoge Scale (VAS).
The median intubation time was shorter for the RW-D compared to the RW-NVG setting (16.5 seconds vs. 30.0 seconds; p = 0,03). We found no difference in median intubation time for the ER and RW-D settings (16.8 seconds vs. 16.5 seconds; p = 0.91). For all scenarios, success rate was 100%. CL and VAS varied between the ER setting (CL 1.8, VAS 2.8), RW-D setting (CL 2.0, VAS 3.0), and RW-NVG setting (CL 3.0, VAS 6.5).
This study suggests that anesthesiologists successfully and quickly can perform ETI in a helicopter setting both in daylight and in darkness using binocular NVG, but with shorter intubation times in daylight.
Night-vision goggles (NVG) in jet fighter aircraft appear to increase the risk of neck strain due to increased neck loading. The present aim was, therefore, to evaluate the effect on neck-muscle activity and subjective ratings of head-worn night-vision (NV) equipment in controlled simulated flights.
Five experienced fighter pilots twice flew a standardized 2.5-h program in a dynamic flight simulator; one session with NVG and one with standard helmet mockup (control session). Each session commenced with a 1-h simulation at 1 Gz followed by a 1.5-h dynamic flight with repeated Gz profiles varying between 3 and 7 Gz and including aerial combat maneuvers (ACM) at 3-5 Gz. Large head-and-neck movements under high G conditions were avoided. Surface electromyographic (EMG) data was simultaneously measured bilaterally from anterior neck, upper and lower posterior neck, and upper shoulder muscles. EMG activity was normalized as the percentage of pretest maximal voluntary contraction (%MVC). Head-worn equipment (helmet comfort, balance, neck mobility, and discomfort) was rated subjectively immediately after flight.
A trend emerged toward greater overall neck muscle activity in NV flight during sustained ACM episodes (10% vs. 8% MVC for the control session), but with no such effects for temporary 3-7 Gz profiles. Postflight ratings for NV sessions emerged as "unsatisfactory" for helmet comfort/neck discomfort. However, this was not significant compared to the control session.
Helmet mounted NV equipment caused greater neck muscle activity during sustained combat maneuvers, indicating increased muscle strain due to increased neck loading. In addition, postflight ratings indicated neck discomfort after NV sessions, although not clearly increased compared to flying with standard helmet mockup.
The Swedish Air Force (SwAF) conducted a study in 2010 to harmonize portrayal of aeronautical info (AI) on SwAF charts with NATO standards. A mismatch was found concerning vertical obstructions (VO). Norway regarded Sweden's existing symbology as a way to solve the problem of overcrowded air charts and the two countries started to cooperate. The result of this development was a new set of symbology for obstacles. The aim of this study was to test the readability of the new obstacle and power line symbols compared to the old symbols. We also wished to assess the readability in NVG illumination conditions, particularly regarding the new symbols compared to the old.
In a randomized controlled study design, 21 volunteer military pilots from the Norwegian and Swedish Air Force were asked to perform tracking and chart-reading tests. The chart-reading test scored both errors and readability using a predefined score index. Subjective scoring was also done at the end of the test day.
Overall response time improved by approximately 20% using the new symbology and error rate decreased by approximately 30-90% where statistically significant differences were found.
The tracking test turned out to be too difficult due to several factors in the experimental design. Even though some caution should be shown in drawing conclusions from this study, the general trends seem well supported with the number of aircrew subjects we were able to recruit.Wagstaff AS, Larsen T. Readability of new aviation chart symbology in day and NVG reading conditions. Aerosp Med Hum Perform. 2017; 88(11):978-984.