Noise during hernia repair may boost wound infection risk

Last Updated: 2015-04-07

By Lisa Rapaport

NEW YORK (Reuters Health) - Noisy operating rooms - particularly during closure - were linked to a higher risk of surgical-site infections (SSIs) after hernia repair in a recent small study.

Researchers at Milton Keynes General Hospital in Buckinghamshire, UK studied 64 men who had open left-sided inguinal hernia repairs done as elective day cases in 2014. The median age was 32 (range, 19 to 37); the median body mass index was 21.9 kg/m2. They had no known risk factors for SSI.

A Lutron Professional Noise Meter was attached to the main operative light directly over the operating field, according to a report by Dr. Shamik Dholakia and colleagues online February 28 in Surgery.

Assistants closed in 59 cases (92%), starting at a median of 51.5 minutes. The median operative time of 57 minutes did not appear to be influenced by the noise levels.

At 30 days, five men (7.81%) had developed superficial SSIs. They received oral co-amoxiclav (amoxicillin/clavulanic acid) for seven days, leading to an increase in hospital costs of 243 pounds/361 dollars per affected patient.

"Noise levels were substantially greater in patients with SSI from time point of 50 minutes onwards, which correlated to when wound closure was occurring," the authors reported.

During periods of greater noise, music and conversation not related to the patient were present, although "the precise level of additional noise contributed by these two factors was not directly quantified, because only the overall noise in room was measured," the authors wrote.

In operations on patients who later developed SSIs, there was a mean increase in noise of 11.337 dB above the background baseline from 50 minutes onward - an increase "significant enough to effect the operation," the authors said, whereas the average increase above baseline was closer to a steady 6 dB in patients without SSIs.

The study is small, and not statistically powered, making it hard to draw conclusions that might apply broadly, the authors admit. They did not respond to a request for comment.

"It's possible that decreased noise in the OR was associated with lower SSI rates because members of the team were able to concentrate more in quiet rooms, leading to faster completion times or fewer errors," Dr. Lauren Hersch Nicholas, an assistant professor in health policy and management and surgery at Johns Hopkins University, told Reuters Health by email.

Quieter rooms might also reflect hospital-level efforts to improve safety, she said.

"While hospitals may want to test whether they can achieve similar improvements in safety by eliminating or reducing the volume on OR music, I would want to see additional experimental evidence about the benefits of noise reduction before encouraging hospitals to undergo significant structural changes or soundproofing efforts," Hersch Nicholas said.

While operations tend to be louder at the end of a procedure, in part due to the start of cleaning the scrub tables, "noise can also be a surrogate parameter for difficult operations or for lack of concentration of the members of the surgical team; this then leads to potential mishandling of the tissue," Dr. Guido Beldi, of the department for visceral surgery and medicine at Bern University Hospital in Switzerland, told Reuters Health by email.

Previous research has shown that "exchanges of case-relevant communication is reduced in the presence of noise," inhibiting an activity that is known to reduce the risk of SSIs, said Beldi.

SOURCE: http://bit.ly/1DZLo9c

Surgery 2015.