To determine the efficacy of a new respiratory monitor, which uses esophageal balloons, in aiding clinicians attempting to wean patients from mechanical ventilation.
Prospective study of patients who were deemed ready to be weaned after having required mechanical ventilation for a minimum of 3 days. Each of the patients served as his or her own control.
University medical intensive care unit.
The series consisted of 23 consecutive patients who were ready to wean from mechanical ventilation.
Before the onset of the study, two weaning strategies were developed. One strategy involved using clinically available weaning parameters. The other strategy involved using esophageal balloon data that was recorded via a new respiratory monitor. Each of the weaning strategies resulted in the development of a scoring system that could be rigidly adhered to and which determined, without bias, to what extent the patient could be weaned each day. Rigid criteria were also developed to determine whether the weaning trial was successful or not. The two strategies were then compared to determine the ability of the strategy to shorten ventilatory time.
Each patient was evaluated daily by the two weaning protocols. At each weaning step, the two protocols were compared with respect to degree of aggressiveness and tolerance of the weaning maneuver by the patient. A protocol was judged superior if it resulted in more aggressive weaning without increased patient intolerance. The clinicians evaluating the patient with the clinical protocol could accelerate or retard the number of weaning steps by one step, based on the patient's clinical state and the clinician's experience. There was no such freedom in the esophageal protocol.
The major finding was that in 40.5% of the instances, the protocol involving the esophageal balloon resulted in more aggressive weaning without patient intolerance. In 11.6% of the cases, the clinical protocol was more aggressive. Both protocols predicted the same number of weaning steps 39.8% of the time. In all these instances, the patient tolerated the weaning suggested. The use of data from the esophageal protocol resulted in weaning the patients 1.68 days faster than the use of data from the clinical protocol.
The respiratory monitor, using esophageal balloon technology, is effective in that it can provide the clinician with data that can result in more aggressive weaning from mechanical ventilation without an increase in patient intolerance. The duration of mechanical ventilation can be shortened when these data are applied via a rigidly controlled weaning strategy.
(Crit Care Med 1995; 23:504-509)
From the Chicago Medical School and the North Chicago Veterans Administration Medical Center, Chicago, IL (Dr. Gluck); the Rush-Presbyterian-St. Luke's Medical Center, Chicago, IL (Drs. Barkoviak, Balk, Casey, and Silver); the Medical College of Toledo, Toledo, OH (Dr. Bone).
This study was funded, in part, by Bicore Monitoring Systems.
Address requests for reprints to: Eric Gluck, MD, North Chicago VA Medical Center, 3001 Green Bay Road, North Chicago, IL 60064.