Comparison of five clinical weaning indices.

Background: Despite extensive data acquired in the area of weaning, clinicians still struggle with the questions of how and when to begin the process. Clinical weaning indices, designed to predict weaning potential, are often difficult to use. They provide an answer at a specific time; extrapolation to the weaning process is rarely possible. No single index has proven to be superior.
Objectives: To test the efficacy of five clinical weaning indices (Burns Weaning Assessment Program; Weaning Index; frequency tidal volume ratio; compliance, resistance, oxygenation and pressure index; and negative inspiratory pressure) at regular intervals during withdrawal of ventilatory support and to determine threshold levels for the program.
Methods: A prospective convenience sample consisted of 37 adult critical care patients requiring mechanical ventilation for at least 7 days and identified as stable and ready to wean. Data were collected on all weaning indices every other day until the patient was weaned.
Results: With the exception of the Burns Weaning Assessment Program, weaning indices did not change significantly from preweaning scores. Furthermore, the results failed to demonstrate that any of the five clinical weaning indices have strong predictive power related to weaning trial outcomes, although all the indices had negative predictive values that may be helpful in predicting unsuccessful weaning trials.
Conclusions: The results of this study suggest that the process of weaning may be enhanced by comprehensive, systematic approaches and that clinical weaning indices like the Burns Weaning Assessment Program might best serve as tools to track trends in progress, keep care planning on target, and prevent unsuccessful weaning trials.