Aim: This project investigates the effect of subjective sleepiness on critical skills performance of National Guard (NG) medical personnel during highly realistic and immersive disaster-training exercises.

Methods: This study used a longitudinal, observational design in a sample (n=77) of NG medical personnel over three high-intensity disaster-training exercises. During three separate 3- to 5-day disaster response training exercises, participants completed a critical skills test four times per day. At the same time, their subjective sleepiness was measured using the Karolinska Sleepiness Scale (KSS). The effect of subjective sleepiness on: (1) reaction time to complete critical skills questions; and (2) accuracy in completing critical skills questions were analyzed using generalized linear mixed models.

Results: With changing disaster response duties and assignments, 91% of participants responded to 2,228 critical skills questions over two to three different disaster exercises. When levels of sleepiness (KSS self-reported scores) were rated as ‘Extremely alert’, response accuracy averaged 91%; however, when self-reported sleepiness was scored as “Extremely sleepy”, accuracy dropped to 60%.

Conclusions: Increasing sleepiness correlated significantly with decreasing accuracy on critical skills questions. Participant professional licensure was also significantly correlated with accuracy of responses to critical skills questions. Military deployments and disaster-training exercises designed to replicate real-world events require prolonged periods of sleep insufficiency or sleep interruptions. Adjustments to shift work for nurses, attention to pre-deployment screening and education, and a change in cultural attitudes may be needed to make a positive difference in morale, mission completion, and casualty reductions.