Efficacy of heat and moisture exchangers in preventing ventilator-associated pneumonia: meta-analysis of randomized controlled trials
- 672 Downloads
Several randomized controlled trials (RCT) have examined the effect of antibacterial humidification strategies, particularly the replacement of heated humidifiers (HH) by heat and moisture exchangers (HME), in preventing ventilator-associated pneumonia (VAP). The present meta-analysis reviews these RCTs.
RCTs were identified by searching the Medline and Cochrane Central Register of Controlled Trials databases from 1990 to 2003. We included RCTs using HMEs in the treatment group and HHs in the control group and reporting the incidence of pneumonia as a study outcome. Two investigators independently abstracted key data on design, population, intervention and outcome of the studies.
Between 1990 and 2003 eight RCTs met the inclusion criteria of this analysis. Pooling the results from these studies revealed a reduction in the relative risk of VAP in the HME group (0.7), particularly in MV with a duration of at least 7 days (five RCTs, relative risk 0.57).
This meta-analysis found a significant reduction in the incidence of VAP in patients humidified with HMEs during MV, particularly in patients ventilated for 7 days or longer. This finding is limited by the exclusion of patients at high risk for airway occlusion from some of the studies. Moreover, contraindications (tenacious secretions, airway obstructive disease, hypothermia) and technical issues of HMEs must be considered. Further RCTs are necessary to examine the wider applicability of HMEs and their extended use.
KeywordsVentilation Pneumonia Infection Humidification Ventilator-associated pneumonia Heat and moisture exchanger
- 6.Tablan OC, Anderson LJ, Besser R, Bridges C, Hajjeh R (2004) Guidelines for preventing health-care-associated pneumonia, 2003: recommendations of CDC and the Healthcare Infection Control Practices Advisory Committee. MMWR Recomm Rep 53:1Google Scholar
- 10.Dreyfuss D, Djedaini K, Gros I, Mier L, Le Bourdelles G, Cohen Y, Estagnasie P, Coste F, Boussougant Y (1995) Mechanical ventilation with heated humidifiers or heat and moisture exchangers: effects on patient colonization and incidence of nosocomial pneumonia. Am J Respir Crit Care Med 151:986PubMedGoogle Scholar
- 11.Branson RD, Davis K Jr, Brown R, Rashkin M (1996) Comparison of three humidification techniques during mechanical ventilation: patient selection, cost, and infection considerations. Respir Care 41:809Google Scholar
- 12.Kirton OC, DeHaven B, Morgan J, Morejon O, Civetta J (1997) A prospective, randomized comparison of an in-line heat moisture exchange filter and heated wire humidifiers: rates of ventilator-associated early-onset (community-acquired) or late-onset (hospital-acquired) pneumonia and incidence of endotracheal tube occlusion. Chest 112:1055PubMedGoogle Scholar
- 33.Vincent JL, Lobo S, Struelens M (2001) Ventilator associated pneumonia: risk factors and preventive measures. J Chemother 13 [Spec no 1]:211Google Scholar