The impact of heart rate-based drowsiness monitoring on adverse driving events in heavy vehicle drivers under naturalistic conditions.

OBJECTIVES: This study examined the influence of a wrist-worn heart rate drowsiness detection device on heavy vehicle driver safety and sleep and its ability to predict driving events under naturalistic conditions. DESIGN: Prospective, non-randomized trial. SETTING: Naturalistic driving in Malaysia. PARTICIPANTS: Heavy vehicle drivers in Malaysia were assigned to the Device (n = 25) or Control condition (n = 34). INTERVENTION: Both conditions were monitored for driving events at work over 4-weeks in Phase 1, and 12-weeks in Phase 2. In Phase 1, the Device condition wore the device operated in the silent mode (i.e., no drowsiness alerts) to examine the accuracy of the device in predicting driving events. In Phase 2, the Device condition wore the device in the active mode to examine if drowsiness alerts from the device influenced the rate of driving events (compared to Phase 1). MEASUREMENTS: All participants were monitored for harsh braking and harsh acceleration driving events and self-reported sleep duration and sleepiness daily. RESULTS: There was a significant decrease in the rate of harsh braking events (Rate ratio = 0.48, p < 0.05) and a fall in subjective sleepiness (p < 0.05) when the device was operated in the active mode (compared to the silent mode). The device predicted when no driving events were occurring (specificity=98.81%), but had low accuracy in detecting when a driving event did occur (sensitivity=6.25%). CONCLUSIONS: Including drowsiness detection devices in fatigue management programs appears to alter driver behaviour, improving safety despite the modest accuracy. Longer term studies are required to determine if this change is sustained.

Comparison of mydriatic regimens used in screening for retinopathy of prematurity in preterm infants with dark irides.

PURPOSE: To determine the mydriatic regimen that provides optimal dilation of the pupil with minimal systemic side effects for screening of retinopathy of prematurity. METHODS: This cross-sectional, randomized, double-masked clinical trial compared cyclopentolate 1% + phenylephrine 2.5%, tropicamide 1% + phenylephrine 2.5%, and a prepared combination of cyclopentolate 0.2% with phenylephrine 1% for pupillary dilation in preterm infants with dark irides. Thirteen infants were randomized to each regimen. Outcomes measured were pupillary dilation, heart rate, blood pressure, abdominal girth, and intolerance to feeds. RESULTS: All three mydriatic regimens provided adequate pupillary dilation at 45 minutes, with dilation sustained at 60 minutes. There was a significant increase in mean blood pressure in the cyclopentolate 1% + phenylephrine 2.5% and the tropicamide 1% + phenylephrine 2.5% groups. Although there was no significant change of abdominal girth in any of the three groups, a total of eight patients developed intolerance to feeds; four (50%) of these infants were from the cyclopentolate 1% + phenylephrine 2.5% group. CONCLUSION: The prepared combination of cyclopentolate 0.2% + phenylephrine 1% appears to be the mydriatic of choice for preterm infants with dark irides as it provided adequate pupillary dilation with the least systemic side effects.