Change of catheters does not reduce pneumonias
Synopsis: Based on the randomized trial by Kollef and colleagues, it is appropriate and cost-effective to recommend change of in-line suction catheters only when they malfunction or become visibly soiled.
Source: Kollef MH, et al. Mechanical ventilation with or without daily changes of in-line suction catheters. Am J Respir Crit Care Med 1997; 156:466-472.
In-line suction catheters that permit endotracheal suctioning of ventilated patients without disconnection of the ventilator circuit are currently in use in many critical care units. The largest manufacturer of these catheter systems recommends changing the catheter every 24 hours because of the possibility of formation of a biofilm that may be a source of organisms causing ventilator-associated pneumonia. In a randomized trial, Kollef and colleagues compared daily catheter replacement with no regularly scheduled replacement. Patients in the latter group received catheter replacement only in the event of catheter malfunction or visible soiling. Two hundred sixty-three patients received daily catheter changes, and 258 received no routine changes. The two groups were very well matched according to demographics, underlying illnesses, severity of illness measured by Apache II score, and known risk factors for pneumonia such as receipt of H-2 blockers, antibiotic therapy, and factors contributing to aspiration. No difference was found in the rates of pneumonia. Furthermore, there was no difference in mortality, length of stay, duration of intubation, or acquisition of new organ system dysfunction.
Comment by Robert R. Muder, MD, hospital epidemiologist, Pittsburgh VA Medical Center.
In-line suction catheters are favored by many critical care units because they permit endotracheal suctioning without disconnecting the patient from the ventilator. One potential drawback of these catheters is the build-up of a biofilm of patient secretions and bacteria that could be aspirated or introduced into the patient’s respiratory tract, increasing the risk of ventilator-associated pneumonia. On the other hand, entering the closed system to suction by traditional means, or to change the catheter, increases the risk of external bacterial contamination. Several previous studies have shown that frequent changes of ventilator circuit tubing do not decrease (and may increase) the risk of ventilator-associated pneumonia.
The study by Kollef and colleagues is convincing because of the large number of patients involved, the close matching of the two treatment groups, the definition of pneumonia used, and the examination of secondary outcomes such as length of intubation and ICU stay. Based on this study, it is appropriate to recommend change of in-line suction catheters only when they malfunction or become visibly soiled. The cost savings are relatively modest, about $39 per patient or $7 per ventilator-patient day. However, in a 20-bed unit this would amount to $51,000 per year exclusive of the time spent by respiratory therapists in routine catheter changes.
Finally, this study is an excellent example of the use of an evidence-based approach to evaluate patient care practices of unproven efficacy.
Harris JS. Pediatric nosocomial infections: Children are not little adults. Infect Control Hosp Epidemiol 1997; 18:739-742.
Nosocomial infections pose a significant threat to the hospitalized child and will continue to be a cause of significant morbidity, mortality, and long-term sequelae, the author of this editorial emphasizes.
"Although more children will be treated as outpatients and be discharged earlier to non-acute-care facilities in the future, hospitalized children will be sicker, requiring more invasive therapies and treatments, putting them at increased risk for hospital-acquired infections," she reports.
Current strategies for surveillance, prevention, and control of nosocomial infections have focused on general hospital services that primarily address the needs of adult patient populations. Although some of these strategies apply to infants and children, it is clear that pediatric patients and pediatric units are unique and require child-specific prevention and control plans.
The author lists the following areas for action to develop child-specific strategies for the prevention and control of pediatric nosocomial infections:
• Surveillance methods using risk stratification for severity of illness need to be developed in order to get baseline data of nosocomial infections in intensive-care and non-intensive-care pediatric settings, as well as non-acute-care institutions, such as long-term-care facilities, medical day-care centers, and pediatric rehabilitation hospitals, to establish benchmark rates that will permit accurate and reliable intra-hospital and inter-hospital comparisons.
• Site-specific risk factors for infections such as device-related bloodstream infections and ventilator-associated pneumonia in children need to be identified.
• Type and incidence of resistant organisms in various pediatric settings (such as acute-care and non-acute-care settings) and in special populations where long-term prophylaxis or frequent courses of antibiotics are used (such as sickle cell, HIV, and cystic fibrosis patients) should be established. Evaluation of antimicrobial prescribing practices will allow development of interventions to control inappropriate use in children.
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Schwartz B, Bell DM, Hughes JM. Preventing the emergence of antimicrobial resistance: A call for action by clinicians, public health officials, and patients. JAMA 1997; 278:944-955.
Addressing antimicrobial use and resistance is one of the most urgent priorities in confronting emerging infectious disease threats, and physicians should begin examining overprescribing patterns in their offices, this editorial from the Centers for Disease Control and Prevention emphasizes.
The rapid spread of resistance demands an immediate and aggressive response, the authors note, encouraging all physicians to examine their own practices and identify where they can decrease unnecessary antimicrobial use. Suggested strategies include improving diagnostic methods or communicating with patients concerning the lack of benefit, potential adverse effects, and development of resistance associated with such therapy.
Respiratory infections account for more than three-quarters of the antimicrobial drug prescriptions written annually in physicians’ offices. Yet most colds and nonspecific upper respiratory infections are viral, and thus do not benefit from antimicrobial therapy. Although subgroups of patients with illness involving cough or bronchitis may benefit from antimicrobial therapy, the vast majority do not, the authors report.
Physicians in focus groups attribute the pattern of overprescribing to unrealistic patient expectations, coupled with insufficient time to discuss with patients why an antibiotic is not needed. Indeed, data from a study of patients with cough suggests such expectations influence prescribing, as the physician’s belief of patient expectation for antimicrobial therapy was directly associated with a diagnosis of bronchitis and inversely associated with a diagnosis of viral infection.
"Although less readily admitted, physicians’ inadequate knowledge of the spectrum of symptoms and signs and the natural history of respiratory illnesses also contributes to antibiotic overuse," they note. "For example, prolonged cough occurs commonly in persons with viral infection and does not necessarily indicate a need for antimicrobial therapy."
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Pfaller MA, Herwaldt LA. The clinical microbiology laboratory and infection control: Emerging pathogens, antimicrobial resistance, and new technology. Clin Infect Dis 1997; 25:858-870.
The clinical microbiology laboratory is an essential component of an effective infection control program, and good teamwork between the two forces can solve nosocomial outbreaks and thwart rising antibiotic resistance, the authors report.
The work required of the clinical microbiology laboratory and of the infection control program has become increasingly complex, demanding, and intertwined in the 1990s. As in the past, the microbiology laboratory must be able to detect and identify microorganisms so that the clinicians can diagnose and treat established infections and the infection control team can monitor, prevent, and control infections in the hospital environment.
However, the number and types of pathogens that the laboratory must detect have increased dramatically. New technology, developed to detect, identify, and characterize microorganisms, has improved significantly the laboratory’s ability to keep up with the rapidly changing nosocomial pathogens.
"If the laboratory and infection control personnel cooperate and collaborate rather than compete, both programs will be successful and the patients and the hospital will benefit because the risk of nosocomial infections and the frequency of resistant organisms will be reduced," they note.
In particular, molecular biological techniques have enhanced the speed and sensitivity of detection methods and have allowed the laboratory to identify organisms that do not grow or that grow slowly in culture. Molecular biological techniques also enable the microbiologist to identify antibiotic resistance genes and to "fingerprint" hospital organisms, thereby facilitating studies of nosocomial transmission.
In addition to performing their traditional roles, albeit with new tools, laboratory personnel must perform some tasks that are specifically designed to facilitate infection control activities. For example, the laboratory should also participate actively in surveillance efforts, and laboratory staff members should help plan and execute microbiological and molecular epidemiological investigations of nosocomial infections. The laboratory staff also must provide the infection control team with high-quality data in a timely fashion and teach the infection control personnel how to use laboratory resources appropriately during epidemiological investigations.
"The microbiology laboratory’s role in monitoring resistance is extremely important to the success of the infection control efforts," the authors conclude. "Laboratory personnel must notify infection control staff immediately when resistant organisms are identified and when new or unusual phenotypic resistance patterns are found so that appropriate isolation precautions can be instituted."
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