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
Oc. Kirton et al., 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(4), 1997, pp. 1055-1059
Purpose: To compare the performance of an in-line heat moisture exchan
ging filter (HMEF) (Pall BB-100; Pall Corporation; East Hills, NY) to
a conventional heated wire humidifier (H-wH) (Marquest Medical Product
s Inc., Englewood, Cole) in the mechanical ventilator circuit on the i
ncidence of ventilator-associated pneumonia (VAP) and the rate of endo
tracheal tube occlusion. Methods: This report describes a prospective,
randomized trial of 280 consecutive trauma patients in a 20-bed traum
a ICU (TICU). All intubated patients not ventilated elsewhere in the m
edical center prior to their TICU admission were randomized to either
an in-line HMEF or a H-wH in the breathing circuit. Ventilator circuit
s were changed routinely every 7 days, and closed system suction cathe
ters were changed every 3 days. HMEFs were changed every 24 h, or more
frequently if necessary. A specific endotracheal tube suction and lav
age protocol was not employed. Patients were dropped from the HMEF gro
up if the filter was changed more than three times a day or the patien
t was placed on a regimen of ultra high-frequency ventilation. The Cen
ters for Disease Control and Prevention (CDC) critt ria for diagnosis
of pneumonia were used; early-onset, community-acquired pneumonia was
defined if CDC criteria were met in less than or equal to 3 days, and
late-onset, hospital-acquired pneumonia was defined if criteria were m
et in >3 days. Laboratory and chest radiograph interpretation were bli
nded. Results: The patient ages ranged from 15 to 95 years in the HMEF
group and 16 to 87 years in the H-wH group (p=not significant), with
a mean age of 46 years and 48 years, respectively. The male to female
ratio ranged between 78 to 82%/22 to 18%, respectively, and 55% of all
admissions were related to blunt trauma, 40% secondary to penetrating
trauma, and 5% to major burns. There was no difference in Injury Seve
rity Score (ISS) between the two groups. Moreover, there was no signif
icant difference in mean ISS among those who did not develop pneumonia
and those patients who developed either early-onset, community-acquir
ed or late-onset, hospital-acquired pneumonia. The HMEF nosocomial VAP
rate was 6% compared to 16% for the H-wH group (p<0.05), and total ve
ntilator circuit costs (per group) were reduced, There were no differe
nces in duration of ventilation (mean+/-SD) if the patient did not dev
elop pneumonia or if the patient developed an early-onset, community-a
cquired or a late-onset, hospital-acquired pneumonia. Moreover, total
TICU days were reduced in the HMEF group. In addition, tile incidence
of partial endotracheal tube occlusion was not significantly different
between the H-wH and the HMEF groups. Conclusions: The HMEF used in t
his study reduced the incidence of late-onset, hospital-acquired VAP,
but not early-onset, community-acquired VAP, compared to the conventio
nal H-wH circuit. This was associated with a significant reduction in
total ICU stay. Disposable ventilator circuit costs in the HMEF group
were reduced compared to the H-wH group in whom circuit changes occurr
ed at 7-day intervals. Clinical implications: The use of the HMEF is a
cost-effective clinical practice associated with fewer late-onset, ho
spital-acquired VAPs, and should result in improved resource allocatio
n and utilization.