Sensorimotor and executive function slowing in anesthesiology residents after overnight shifts.

STUDY OBJECTIVE

Medical residents working overnight call shifts experience sleep deprivation and circadian clock disruption. This leads to deficits in sensorimotor function and increases in workplace accidents. Using quick tablet-based tasks, we investigate whether measureable executive function differences exist following a single overnight call versus routine shift, and whether factors like stress, rest and caffeine affect these measures.

DESIGN

A prospective, observational, longitudinal, comparison study was conducted.

SETTING

An academic tertiary hospital's main operating room suite staffed by attending anesthesiologists, anesthesiology residents, anesthesiologist assistants and nurse anesthetists.

PATIENTS

Subjects were 30 anesthesiology residents working daytime shifts and 30 peers working overnight call shifts from the University of Texas Health Science Center at Houston.

INTERVENTIONS

Before and after their respective work shifts, residents completed the Stanford Sleepiness Scale (SSS) and the ProPoint and AntiPoint tablet-based tasks. These latter tasks are designed to measure sensorimotor and executive functions, respectively.

MEASUREMENTS

The SSS is a self-reported measure of sleepiness. Response times (RTs) are measured in the pointing tasks.

MAIN RESULTS

Call residents exhibited increased RTs across their shifts (post-pre) on both ProPoint (p=0.002) and AntiPoint (p<0.002) tasks, when compared to Routine residents. Increased stress was associated with decreases in AntiPoint RT for Routine (p=0.007), but with greater increases in sleepiness for Call residents (p<0.001). Further, whether or not a Call resident consumed caffeine habitually was associated with ProPoint RT changes; with Call residents who habitually drink caffeine having a greater Pre-Post difference (i.e., more slowing, p<0.001) in ProPoint RT.

CONCLUSIONS

These results indicate that (1) overnight Call residents demonstrate both sensorimotor and cognitive slowing compared to routine daytime shift residents, (2) sensorimotor slowing is greater in overnight Call residents who drink caffeine habitually, and (3) increased stress during a shift reduces (improves) cognitive RTs during routine daytime but not overnight call shifts.