CDC bans expensive ritual of routine ventilator breathing circuit changes

Draft pneumonia recommendations may breathe life into budgets

In new guidance that should spell millions of dollars saved for the nation’s hospitals, the Centers for Disease Control and Prevention (CDC) is calling a halt to routine changes of ventilator breathing circuits. The move comes in new draft recommendations to prevent hospital-acquired pneumonia, one of the deadliest and most frequent nosocomial infections. In light of the guidelines, which are open for comment until Oct. 18, 2002, ICPs should reassess their policies for ventilated patients. Of course, the recommendation comes in draft form, but the change is likely to remain in the final version because it was given the strongest endorsement (1A) by the CDC’s Healthcare Infection Control Practices Advisory Committee.

Frequent, routine circuit changes originally were designed to protect patients from aspirating the condensate that collects in the vent tubing down into their lungs. Steadily emerging science now has established a contrary view: frequent handling and changing the vent tubing may actually put patients at greater risk of exposure to bacterial pathogens that lead to ventilator-associated pneumonia (VAP). Thus, the CDC dropped its 1996 recommendation to change the breathing circuits "no more frequently than 48 hours." The new recommendation is "do not change routinely, on the basis of duration of use, the ventilator circuit (i.e., ventilator tubing and exhalation valve, and the attached humidifier) that is in use on an individual patient. Rather, change the circuit when it is visibly soiled or mechanically malfunctioning."1

Substantial savings projected

"If this is implemented by the majority of hospitals, it will literally save hundreds of thousands of dollars, if not millions of dollars," says Robert Garcia, MT, CIC, assistant director of infection control at Brookdale University Hospital and Medical Center in Brooklyn, NY. "Because of the advances in ventilators, we do not need to do a lot of things that we used to do — the changing of these circuits and all of that. The more you manipulate the devices, the greater the risk that the person is going to aspirate something."

Having already extended change-out times from two to seven days, Garcia is ready to adopt the new recommended policy and simply leave circuits in place. "I’m 100% sure that is the way we are going to go," he says.

Another key change in the ventilator guidance is a similar recommendation regarding in-line suction catheters used with closed-systems suction. The CDC draft now advises that clinicians only change the in-line suction catheter when it malfunctions or becomes visibly soiled. "That is a major change in recommendations," Garcia says. "In the last guideline, they didn’t even address the issue of when to change the closed-suction devices."

Some manufacturers recommend changing out the in-line suction catheter every 24 hours, but there has been little evidence to support the necessity of the practice, he adds. "These things cost about $10 a day," Garcia says. "Changing it every single day — think about a patient who is averaging seven days [on a ventilator]. Now, I only change it when it is visibly soiled or we have mechanical failure. That is a major cost reduction. I mean, I run 60-65 vents on any given day."

Weighing the evidence

In making the new ventilator circuit recommendations, the CDC cited studies demonstrating the safety and cost-effectiveness of extending change-out intervals. In one study, investigators found no increase in the incidence of VAP and a savings of more than $110,000 per year in materials and personnel salaries when breathing circuits were changed every seven days rather than every 48 hours.2 Similar studies have found that when circuits are not changed for the duration of use by a patient, the risk of a patient developing pneumonia [eight (29%) of 28] is very similar to the risk when circuits were changed every 48 hours [11 (31%) of 35].3 Finally, a recent study showed that patients whose breathing circuits were left unchanged indefinitely (unless observed to be grossly contaminated) for the duration of mechanical ventilation did not have a higher risk of acquiring pneumonia compared with those whose breathing circuits were changed routinely every seven days.4

"These findings indicate that the previous CDC recommendation to change ventilator circuits routinely on the basis of duration of use should be changed to one that is based on visual and/or known contamination of the circuit," the draft guidelines state. "This change in recommendation is expected to result in large savings in device use and personnel time for U.S. health care facilities."

Naturally, the level of savings will depend on current practice at individual hospitals, many of which already have cut tube-changing frequency as more patient safety data emerged.

"There is definitely a cost savings from the standpoint of not changing your circuits," says Michael Byet, BA, RRT, technical specialist for the respiratory care department at University Arizona Medical Center in Tucson. "There are some hospitals back East that are doing one-week change-outs, and so forth. We have been at two weeks for a long time," he says. "We initially went to one week, and then extended it because we weren’t seeing any increase in infection rates at all. Our VAPs actually went down." Indeed, it was during a multifaceted effort to lower VAPs that another ICP took a look at her hospital’s change-out policies.

A significant finding was that the ventilator circuit was considered to have three components, with tubing changed every seven days and the heat moisture exchanger (HME) and in-line suction catheter changed daily (though not necessarily at the same time), explains Margaret Bertrand, RN, BSN, NMCC, an ICP at the Veterans Affairs Medical Center in Lexington, KY. The VAP rate rose to 41 infections per 1,000 patient days under the old policy.

A systems breakdown

"I did some unobtrusive observation, watching people, and there was frequent breaking of the systems," she says. "You would have nurses breaking the system to suction and then respiratory would come along 15 or 20 minutes later and break the system again to do a treatment or change out an HME."

As a result, the policy was changed. The three components of the ventilator circuit are managed as a single closed unit, which is changed only if obvious soilage or mechanical malfunction occurs. Such soilage is typically blood or vomit, so the need for change-out is obvious, Bertrand says. "Only respiratory therapists can change the ventilator tubing. They set it up initially, and they check it every four hours. Nursing no longer breaks the system to change out suction catheters. In the case of an emergency, of course, they would [take measures]. We’re still seeing good results. For the first and second quarter of 2002, we only had one vent pneumonia [infection]."

Other interventions — including staff education and an emphasis on waterless hand washing — also contributed to the rate reduction. Having anticipated the CDC’s national recommendation, Bertrand has no doubt such policies are the wave of the future. "Back in the mid-1970s or so, there was the same problem with urinary tract infections, and then they went to the closed system for the Foley," she says. "That did help. I think this is the same kind of thing — that constant breaking of the system and messing with it essentially colonizes the tubing and exposes the patient to whatever bacteria [workers] have on their hands."

Looking only at equipment, Bertrand estimates the new policy is saving her hospital $16,000 a year. Other savings that can be calculated in are personnel time and — if VAP rates go down — the prevention of nosocomial pneumonia. According to one study, VAP infections prolong hospitalizations and increase costs by an average of $17,677 per patient.5 "Since we reduced our vent pneumonias so dramatically over time, of course, we are saving patient days of care," she says. "For our patients, we were adding 10 to 20 days [per infection], most of it spent in the ICU. So that is really expensive."

[Editor’s note: The complete CDC draft pneumonia guideline has been posted on your subscriber web site at www.HIConline.com under guidelines and regulations. You may submit comments on or before Oct. 18, 2002, to the CDC Resource Center, Attention: PNGuide DHQP/CDC, Mailstop E-68 1600 Clifton Road N.E., Atlanta, GA 30333. Fax: (404) 498-1244. E-mail: pncomments@cdc.gov.]

References

1. Centers for Disease Control and Prevention. Healthcare Infection Control Practices Advisory Committee. Draft Guideline For Prevention Of Healthcare-Associated Pneumonia. Atlanta; 2002.

2. Hess D, Burns E, Romagloni D, et al. Weekly ventilator circuit changes: A strategy to reduce costs without affecting pneumonia rates. Anesthesiology 1995; 82:903-911.

3. Dreyfuss D, Djedaini K, Weber P, et al. Prospective study of nosocomial pneumonia and of patient and circuit colonization during mechanical ventilation with circuit changes every 48 hours versus no change. Am Rev Respir Dis 1991; 143:738-743.

4. Kollef MH, Shapiro D, Fraser VJ, et al. Mechanical ventilation with or without 7-day circuit changes. Ann Intern Med 1995; 123:168-174.

5. Stone PW, Larson E, Kawar LN. A systematic audit of economic evidence linking nosocomial infections and infection control interventions: 1990-2000. Am J Infect Control 2002; 30:145-152.