a Source of Operating Room Contamination

Hands of Anesthesia Providers May Be a Source of Operating Room Contamination

Laurie Barclay, MD

January 4, 2011 — The contaminated hands of anesthesia providers are a significant source of patient environmental and stopcock set contamination in the operating room, according to the results of a study by Randy W. Loftus, MD, from Dartmouth-Hitchcock Medical Center in Lebanon, New Hampshire, and colleagues, reported in the January 2011 issue of Anesthesia & Analgesia.

"As anesthesiologists, we like to think that the surgical drapes protect the patient from tens of trillions of microorganisms that are in and on our bodies," said editor-in-chief of Anesthesia & Analgesia Steven L. Shafer, from Columbia University in New York, NY, in a news release. "Nope! These studies provide evidence that our bacterial flora contribute to surgical site infections."

The hypothesis tested by this study was that bacterial contamination of anesthesia provider hands before patient contact is a risk factor for direct intraoperative bacterial transmission. At Dartmouth-Hitchcock Medical Center, a tertiary care and level 1 trauma center with 400 inpatient beds and 28 operating suites, the first and second operative cases in each of 92 operating rooms were randomly selected for analysis. After exclusion of 10 pairs of cases because of broken or missing sampling protocol and lost samples, 82 paired samples were analyzed.

Using a previously validated protocol, the investigators identified cases of intraoperative bacterial transmission to the patient IV stopcock set and the anesthesia environment (adjustable pressure-limiting valve and agent dial) in each pair of operating rooms. Biotype analysis allowed comparison of these identified organisms to those isolated from the hands of anesthesia providers, which were cultured before each case began. When the same biotype of potential pathogen was isolated from the patient stopcock set or environment and from the hands of providers, it was considered to be provider-origin transmission.

By assessing isolated potential pathogens identified at the start of case 2, the investigators also assessed the efficacy of the current intraoperative cleaning protocol, and they defined poor intraoperative cleaning as 1 or more potential pathogens found in the anesthesia environment at the beginning of case 2 that were not there at the start of case 1. To identify risk factors for contamination, the investigators collected clinical and epidemiologic data on all 164 cases (82 case pairs).

Intraoperative bacterial transmission to the IV stopcock set occurred in 11.5% (19/164) of cases, of which 47% (9/19) were of provider origin. Intraoperative bacterial transmission to the anesthesia environment occurred in 89% (146/164) of cases, 12% (17/146) of which were of provider origin.

Independent predictors of bacterial transmission events not directly linked to providers were the number of rooms that an attending anesthesiologist supervised simultaneously, the age of the patient, and patient discharge from the operating room to an intensive care unit (ICU).

Limitations of this study include the potential insensitivity of the methodology; sampling of hands only in a single time window; lack of sampling of provider hands if prior physical patient contact had occurred; and provider knowledge of the study, which may have led to exaggerated hand hygiene compliance and therefore underestimated the significance of provider hand contamination before patient care.

"Although we know that hand-washing is an important step, our compliance is poor, and there is little excuse for hospitals not implementing systems that facilitate compliance with hand-washing guidelines," Dr. Shafer said. "However, as [this report suggests], it is time to look at additional measures to protect our patients from the biofilm that we take into the operating room every day."

The study authors have disclosed no relevant financial relationships.

Anesth Analg. 2011;112:98-105. Abstract

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