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A Risk Factor for Hospital-Acquired Infections: Hand Contamination by Anesthesia Providers
Abstract & Commentary
By Leslie A. Hoffman, RN, PhD, Department of Acute/Tertiary Care, School of Nursing, University of Pittsburgh. Dr. Hoffman reports no financial relationship relevant this field of study.
This article originally appeared in the April 2011 issue of Critical Care Alert. It was edited by David J. Pierson, MD, and was peer reviewed by William Thompson, MD. Dr. Pierson is Professor, Pulmonary and Critical Care Medicine, Harborview Medical Center, University of Washington, Seattle, and Dr. Thompson is Associate Professor of Medicine, University of Washington, Seattle. Drs. Pierson and Thompson report no financial relationships relevant to this field of study.
Synopsis: Bacterial transmission to the IV stopcock set was documented in 19/164 cases (11.5%); 47% of these cases were of provider origin and linked to hands of anesthesia providers.
Source: Loftus RW, et al. Hand contamination of anesthesia providers is an important risk factor for intraoperative bacterial transmission. Anesth Analg 2011;112:98-105.
In a prior study, investigators at dartmouth-hitchcock Medical Center linked intraoperative contamination of patients' IV stopcocks with an increase in patient mortality. The present study was conducted to test the hypothesis that bacterial contamination of anesthesia provider hands before patient contact was an important risk factor for intraoperative bacterial transmission. The first and second operative cases in each of 82 randomly selected operating rooms (OR) were used for analysis, yielding 164 cases. Prior to the start of the first case, cultures were obtained from two sites on the anesthesia machine (APL valve and agent dial) and the patient's IV stopcock. Concurrently, the hands of the assigned anesthesia provider, e.g., anesthesiologist, resident physician, or CRNA, were sampled as they entered the OR but before patient contact. At completion of the first case and before the start of the second case, the two sites (anesthesia machine, stopcock) were again sampled. Hands of anesthesia providers were also sampled when they entered the OR before the start of the second case. Transmission events were defined as potential pathogens present at the end of a case not present at the beginning of the case. Using biotype analysis, comparisons were then made with samples from the hands of anesthesia providers. To be identified as transmitted, an organism was required to have an identical biotype to the same organism found on the providers' hands.
Overall, 66% of provider hands were contaminated with one or more major pathogens, e.g., methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococcus (VRE), etc. Bacterial transmission to the IV stopcock was identified in 19/164 cases (11.5%); of these cases; 9/19 (47%) were of provider origin. Bacterial transmission to anesthesia equipment was identified in 146/164 (89%) of cases; of these cases, 17/146 (12%) were of provider origin. Contamination of the environment before the start of case two (a measure of decontamination efficacy) occurred in 6/82 (7%) of the ORs and was linked to stopcock contamination in 1/19 (5%) of cases. Anesthesiologists had significantly less overall hand contamination than residents and CRNAs. The number of rooms supervised by the attending anesthesiologist, age of the patient, and patient discharge from the OR to an ICU were independent predictors of bacterial transmission not linked directly to providers.
We are constantly reminded by old and new studies that health care provider actions place patients at risk for infection. Although we know that hand hygiene is critical to preventing hospital-acquired infections, we often take shortcuts that can expose patients to risk. In confirmation, this study documented a case of intraoperative horizontal transmission that involved: 1) provider negative at the start of case one; 2) stopcock contamination by organisms brought by second provider; 3) ineffective decontamination, and; 4) contaminated stopcock during case two attributed to the original organism.
This study included many steps to rigorously isolate sources of contamination. Baseline bacterial cultures were obtained after active decontamination of the equipment sites by the investigators. All patients received fresh IV stopcocks immediately before the first case began. Anesthesia providers were asked to use the stopcock set identified by the investigators for all medication administration. Hand samples were not obtained if the anesthesia provider had physical contact with the patient. Finally, all transmitted organisms were compared using biotype analysis.
Findings of this study target hand contamination from organisms brought into the OR at the time of the first case as a major problem. As well, findings suggested modifiable risk factors. It might be expected that contamination would increase over time as providers moved from room-to-room during cases. Instead, the first case was associated with the larger magnitude of contamination. Strategies to insure adherence to established hand hygiene practices before first entering the OR would thus likely eliminate a substantial portion of the problem. The solution could be a simple as a surgical scrub for all anesthesia providers and institution of rigorous monitoring practices to objectively identify success of this strategy or additional risk factors. The cost of surgical site infections to patients, families and the nation is enormous. Greater attention placed on the simple things, e.g. explicitly following hand hygiene practices, takes limited time and has great potential benefits.