Bouley G H, Froman R, Shah H
Surgical Intensive Care Unit, Yale New Haven Hospital, CT 06510.
Heart Lung. 1992 Sep-Oct;21(5):471-6.
To compare the degree of dyspnea experienced by ventilator-dependent patients receiving synchronized intermittent mandatory ventilation (SIMV) versus T-piece or pressure support ventilation (PSV) weaning. The relationship between self-reported perceptions of dyspnea and physiologic variables observed during weaning trials was examined. Variables included heart rate, respiratory rate, minute ventilation, and oxygen saturation as measured by a pulse oximeter.
Quasi-experimental, counterbalanced design with repeated measures.
Medical intensive care unit of a large university-affiliated medical center.
Nine mechanically ventilated patients diagnosed with chronic obstructive lung disease. The patients were admitted for respiratory failure between May 1990 to November 1990. Six tolerated SIMV 4 versus T-piece trials; three were placed in the SIMV 8 versus PSV trials.
Each patient's perception of dyspnea was measured using a visual analog scale (VAS) at the initiation and at 5-minute intervals of 20-minute weaning trials. Physiologic indicators were noted simultaneously with VAS ratings of dyspnea.
Findings indicated no difference in the degree of dyspnea experienced between weaning methods compared. Within-subject regression analysis on VAS scores revealed individual differences in the relationship between physiologic indicators and perceptions of dyspnea.
The patient's experience of dyspnea during the weaning process can be a valuable guide to observe the patient's progress. The VAS serves as a reliable, easy-to-use tool for quantifying the patient's perception of dyspnea.
