Noise level and surgeon stress during thyroidectomy in an endocrine surgery operating room

Noise in the operating room is an ongoing problem that impacts the outcome of any surgery. Noise as a stressor can produce a startling reaction and activate the fight or flight response of the autonomic and endocrine systems. The psychobiology of stress as assessed by salivary cortisol level is a sensitive measure of allostatic load. This study aims to correlate, both subjectively and objectively, the salivary cortisol levels of the surgeon with noise level measurement in an endocrine surgery operating room (OR).

A prospective observational study was conducted in the Endocrine surgery OR of a tertiary care center. We recorded the noise from the shifting in of patients in the OR to shifting out using a digital sound level meter. The operating surgeon (S) provided two salivary cortisol samples (normal salivary cortisol <5 nmol/L), one baseline and another after the procedure. The questionnaire for the assessment of distraction during thyroidectomy was filled in by the S at the end of the procedure. Salivary cortisol levels were analyzed using SLV-4635 (formerly SLV-2930) DRG Instruments GmbH German using the ELISA technique. Statistical analysis was performed using SPSS 22.0.

A total of 37 procedures with 74 salivary cortisol samples and 259 questionnaire responses from S were analyzed. All patients with only benign FNAC were operated upon (64.9% colloid). Mean TSH levels were 3.5 ± 6.7 mIU/L. The majority had a solitary thyroid nodule (STN) (25/37, 67.6%). Nineteen patients (51.3%) underwent open hemithyroidectomy, 10 patients total thyroidectomy, and eight patients endoscopic hemithyroidectomy. The mean noise level in the OR was 70 db. The maximum and minimum noise level in the OR was 90.06 and 51.81 dB, respectively. A total of 74 salivary cortisol samples from the S were collected (baseline and post-noise exposure) and mean cortisol levels were recorded. The surgeon was more significantly affected by surrounding noise, especially during critical phases 3 of surgery, mainly, RLN dissection and parathyroid dissection as recorded by their responses in the questionnaire (p = 0.003). The maximum value of post-operative salivary cortisol of surgeon was recorded as 23. 48 ng/mL and the minimum value recorded was 0.49 ng/mL. The difference in baseline cortisol and post-noise exposure cortisol levels of surgeon was found to be significant (p < 0.001). Maximum and mean noise levels were significantly associated with post-noise exposure salivary cortisol elevation in the surgeon (p = 0.032 and 0.014, respectively). The noise levels during RLN dissection were borderline significant with the post-noise exposure salivary cortisol of the surgeon (p = 0.055).

Our research is the first such study which has been done to assess noise levels and their effect on thyroidectomy using objective salivary cortisol measurement. It challenges the misconstrued notion that visceral surgeries requiring lesser instruments are not associated with noise-related stress. Noise is a major distraction and the effect of long-term effect on the entire surgical team needs to be studied.