Contact precautions: A sacred cow?
Contact precautions: A sacred cow?
Decisions should be locally based
Some infection preventionists have raised concerns about the unintended consequences of contact isolation in hospitals, which are often tied to active screening cultures to detect particular pathogens such as methicillin-resistant Staphylococcus aureus(MRSA).
How does the IP balance the effort to protect other patients from those isolated with the complex and potentially detrimental effects of the use of barrier precautions by health care workers entering the room? Might it be better to treat all patients with standard precautions, focusing on reinforcing hand washing rather than isolating patients? Kathryn Kirkland, MD, health care epidemiologist at Dartmouth-Hitchcock Medical Center in Lebanon, NH, recently took a thoughtful, near-philosophical look at such questions, concluding that local institutional factors should ultimately determine whether a hospital is better served by invoking contact isolation or simply focusing on hand hygiene.
"If hand hygiene compliance is very high, it's less likely that adding contact isolation is going to be of direct benefit — compared to an institution that has low hand hygiene compliance [and] can't make any progress getting people to wash their hands," she said recently in Fort Lauderdale, FL, at the annual conference of the Association for Prevention of Infection Control and Epidemiology (APIC). "You may need to use gloves instead. They may be a safer alternative for you. If you are dealing with a situation where you have HAIs under control and your rates are low, [then] perhaps you don't need contact isolation.
"Whereas if you are having difficulty getting infections under control, even if you have already achieved hand hygiene, that may be a situation where you want to pull another tool out of the tool box. If the goal of your infection prevention program — as ours is at Dartmouth, is to prevent infections due to all organisms — then the use of contact isolation directed toward individual organisms does not make very much sense."
Kirkland said such decisions should be viewed in a traditional public health context, which often must balance the rights of an individual vs. the good of a group. Patient isolation is an ethical issue in this sense, subjecting one person to a potentially harmful intervention for the benefit of others. She noted that the theoretical rationale for isolation — the aim to interrupt transmission of organisms — can be accomplished, as well, through hand hygiene.
"Future guidelines should acknowledge the need to consider local context to weigh the benefit and harm in individual settings so that people have room to create flexible interventions that make sense," Kirkland told APIC attendees.
"It is really critical that future research focus not on the questions 'yes' or 'no' — should we use isolation [or not] — but the question for almost every intervention that we make is under what circumstances is this intervention of added benefit and under what circumstances is it not needed?"
"Once patient colonization is established — and I think this is an important thing to really think about — isolation does not play a role in preventing clinical infection, nor does it prevent clinical infection in a patient who came into a hospital colonized," she said. "Isolation operates by interrupting transmission of organisms. Hand hygiene does that in another way as well."
The litany of unanswered questions surrounding the issue includes:
- Do we really know if a colonized patient is as likely to transmit organisms as an infected one?
- How about patient colonization that is identifiable only by molecular testing of their nasal swab or their stool?
- Is the site of infection important in terms of transmission likelihood?
- Is the identity of the organism important? Does MRSA really spread more readily than drug-susceptible staph?
"I think these are unanswered questions," Kirkland said. "l at least challenge you to think about whether these are unanswered questions.
We make a lot of assumptions that we do know the answers to these questions already and I don't think we do."
Indeed, citing review studies that have looked at contact isolation, Kirkland emphasized that much of the literature is made up of outbreak reports, using multiple interventions in widely varying settings.1,2 "We really don't know the answer to the basic question, is isolation effective? Most of the [studies] are generated by people like you and me who had an experience, usually with an outbreak, where they had to do things to control the outbreak and at the end of this experience they wished to share their learning with others," she said. "So, they published the information about what worked in the outbreak."
It may be sobering to conclude that a common infection control practice is not supported by clinical trials or even controlled studies, but Kirkland took it a step further. "The most important question has not been answered yet, and that is, 'is isolation of added benefit beyond the practice of hand hygiene before every patient contact?'" she asked. "Or, to modify that, under what circumstances is isolation of benefit beyond hand hygiene?"
The questions are hard to answer in part because there is little information on compliance with contact isolation and hand hygiene during many studies and outbreak interventions. "Even when we say we are looking at the affect of isolation, we often find that [compliance] was not followed in the studies that we are using as evidence," Kirkland said.
Studies of the harm of isolation fared slightly better, but Kirkland took some issue with the broad perception that isolation leads to substandard care and even psychological effects such as increased depression. Some studies have suggested as much, as health care workers may be reticent to enter the room due to the requirement of donning protective gear such as gloves and gowns. Fair enough, but Kirkland made the paradoxical point that such a result could actually be helpful since it may limit opportunities for transient spread of organisms by health care workers.
"There is not a clear association that more care is better care," she said. "How could less care not be worse care in this situation? Well theoretically, less contact with health care providers could result in fewer instances of infection from an endogenous source, or it could reduce vectorborne transmission from health care workers that haven't washed their hands before they came into the room."
There is some evidence that isolated patients have longer lengths of stay, but she uncovered no significant differences in outcomes such as mortality.
The cost factors are elusive, as well, because they ultimately come down to "how many people are isolated for how long and, how hard we have to look to find the ones to isolate," Kirkland told APIC attendees. "Does isolation and the work required to maintain it by people like you divert resources from other important prevention efforts? That is the question that those in the room can answer better than I can."
Overall, there is some evidence that strategies that include isolation can stem outbreaks, but the argument is less compelling for the role of isolation in nonoutbreak settings for the control of endemic health care infections, she noted.
"To date, the evidence is lacking for the role of isolation alone in preventing infections," Kirkland said. "With respect to harm, there is good evidence that care is different between isolated and nonisolated patients. However, to date, strong evidence of specific harm is still lacking. There is not enough strong evidence to justify dogmatism about isolation, either for it or against it. I strongly believe that individualizing decision making about isolation is justified, and you really have to consider the benefit-to-harm ratio in your individual situation in order to make a decision that makes sense for your local setting. I believe that hand hygiene should be prioritized because we do have evidence that it works when it is implemented, and it causes no harm."
References
- Cooper BS, Stone SP, Kibble CC, et al. Isolation measures in the hospital management of methicillin-resistant Staphylococcus aureus (MRSA): Systematic review of the literature. Br Med J 2004; 329:533-539.
- Marshall C, Wolfe R, Mossman T, et al. Risk factors for acquisition of methicillin-resistant Staphylococcus aureus by trauma patients in the intensive care unit. J Hosp Infect 2004; 57:245-252.
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