Heat and moisture exchangers in mechanically ventilated intensive care unit patients: a plea for an independent assessment of their performance.
OBJECTIVE
To determine whether use of a hygroscopic and hydrophobic heat and moisture exchanger (HME) for 7 days without change affects its efficiency in long-term, mechanically ventilated, chronic obstructive pulmonary disease (COPD) patients.


METHODS
Prospective, randomized, controlled clinical study comparing two combined HMEs.


METHODS
Medical intensive care unit at a university teaching hospital.


METHODS
Long-term, mechanically ventilated, COPD patients compared with non-COPD patients.


METHODS
In the first part of the study, COPD patients were studied with the Hygroster HME changed once a week. For the second part, the Hygroster was assessed in non-COPD patients and compared with the Hygrobac HME used in COPD and non-COPD patients for 1 wk without change. Devices could be changed if hygrometric measurements indicated insufficient humidity delivery.


RESULTS
Daily measurements were recorded for inspired gas temperature and relative and absolute humidity. Ventilatory variables, clinical indicators of efficient humidification, were also recorded. No tracheal tube occlusion occurred. However, contrary to the manufacturer advertisement, the Hygroster experienced surprisingly low values for absolute humidity in both COPD and non-COPD patients. Such events did not occur with the Hygrobac. Absolute humidity with the Hygroster was constantly and significantly lower during the 7-day study period than with the Hygrobac. Absolute humidity measured in COPD patients was identical to that measured in the rest of the study population with both HMEs.


CONCLUSIONS
Manufacturer specifications and bedside measurements of absolute humidity differed considerably for the Hygroster, which in certain instances did not achieve efficient humidification in both COPD and non-COPD patients. This did not occur with the Hygrobac, which performed well throughout the 7-day period in both COPD and non-COPD patients. Our results speak for independent and evaluation of HMEs.
Thiéry
Guillaume
G
Service de Réanimation Médicale, Hôpital Louis Mourier (Assistance Publique-Hôpitaux de Paris), Colombes, France.
Boyer
Alexandre
A
Pigné
Etienne
E
Salah
Amar
A
De Lassence
Arnaud
A
Dreyfuss
Didier
D
Ricard
Jean-Damien
JD
D000368:Aged; D000704:Analysis of Variance; D016022:Case-Control Studies; D004209:Disposable Equipment / Q000592:standards*; D004866:Equipment Contamination; D004868:Equipment Failure; D004869:Equipment Safety; D006358:Hot Temperature / Q000627:therapeutic use*; D006801:Humans; D006813:Humidity; D057927:Hydrophobic and Hydrophilic Interactions; D017053:Infection Control / Q000379:methods; D008134:Long-Term Care; D008875:Middle Aged; D009330:Nebulizers and Vaporizers / Q000592:standards*; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000628:therapy*; D012121:Respiration, Artificial / Q000009:adverse effects / Q000295:instrumentation*; D013997:Time Factors; D016896:Treatment Outcome; D017155:Wettability