The Science Journal of the American Association for Respiratory Care

2009 OPEN FORUM Abstracts

ANALYSIS OF AIRWAY RESISTANCE AND SPUTUM CONSISTENCY FOR PATIENTS SWITCHED FROM HEAT AND MOISTURE EXCHANGER TO HEATED HUMIDIFIER

John S. Emberger, Joel M. Brown, Francis Gott, Melani Murphy; Respiratory Care, Christiana Care Health System, Newark, DE

BACKGROUND: We instituted widespread use of heat and moisture exchangers (HME) last year at our hospital. We use criteria published by Branson et. al.1 to determine heated humidifier (HH) versus HME use on mechanically ventilated patients. We replace HME’s three times per week, or PRN for secretions in the HME. The most common criteria for HH is thick secretions for two sequential suctioning events. Several articles have demonstrated a reduced endotracheal tube lumen over time when using HME’s. We wanted to examine Raw and sputum consistency over time, for patients that required a change from HME to HH based on our humidification criteria. METHODS: An IRB approved retrospective evaluation of all mechanically ventilated patients was performed. Data collected included: type of humidification, duration of mechanical ventilation, calculated Raw every 8 hours, documented sputum consistency. RCP’s perform a measurement of Raw every 8 hours, with a plateau manuver. RCP’s document sputum consistency. We included patients that were switched from HME to HH between June 2008 to June 2009. We excluded patients that were only on HME or HH and patients not on a ventilator capable of a square waveform for the Raw measurement. We analyzed Raw over time for up to 5 days on HME (prior to HH use) and up to 5 days on HH after switching from HME. RESULTS: We identified 477 patients who were switched from HME to HH. In the 5 days on HME (prior to switching to HH) there was ±4% variation in Raw. In the 5 days after switching to HH there was variation from +1% to -8% in Raw. See figure for percent change in Raw over time. Thick secretions were documented 33% of the time while patients were on HME, and 53% of the time while patients were on HH. No true documented tube occlusions occurred. CONCLUSIONS: At our hospital we evaluated over 400 patients who were switched from HME to HH based on humidification criteria. We did not observe increased Raw while on HME, even as criteria were met that required a switch to HH. We did not observe increased Raw while on HH despite a higher percentage of patients with thick secretions. Frequency of thick secretions does not appear to correlate with Raw. REFERENCE: 1) Branson RD, Davis K, Campbell RS, Johnson DJ, Porembka DT. Humidification in the intensive care unit. Prospective study of a new protocol utilizing heated humidification and a hygroscopic condenser humidifier. Chest 1993;104(6):1800–1805. Sponsored Research - None

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