Measurement of Trauma Caregiver Stress: Validation of Heart rate variability in a Real-World Surgical Setting.

Background: Acute stress is a potentially modifiable risk-factor that contributes to errors in trauma care. Research on stress mitigation is limited by the lack of a validated objective measure of surgeon stress. We sought to validate HRV in a real-world surgical setting by comparison to the Subjective Units of Distress Score (SUDS), and correlation with self-reported peak stress moments.

Methods: Attending and resident surgeons on the trauma team at a Level I Trauma Center wore armbands to measure HRV. Stress-associated blunting of HRV was analyzed using the standard deviation of N-N intervals (SDNN) and the root mean square of successive differences . Perceived stress was measured with the SUDS at random intervals and at perceived stress peaks. SUDS and HRV metrics were compared with a mixed effect regression model. Correlation between binned SUDS quartiles and HRV was evaluated. HRV at reported peak-stress moments were compared to shift baseline values.

Results: Twelve participants were monitored for 340 h, producing 135 SUDS responses and 65 peak-stress time points. Regression analysis demonstrated no correlation between HRV and SUDS. With a binned approach, decreased SDNN was associated with an elevated SUDS (P = 0.03). The self-identified peak-stress moments correlated with decreases in both SDNN and root mean square of successive differences (P = 0.02; P < 0.01).

Conclusions: HRV by SDNN analysis correlated with heightened perceived stress, supporting its validity as a measure. However, the wide, frequent variation of HRV tracings within subjects, the sensitivity of HRV to of analytic technique, and the impact of confounders may limit its utility as an education or research tool.

Level Of Evidence: V Diagnostic test.