WHAT'S THE BEST WAY TO WEAN FROM THE VENTILATOR?

For years, clinicians have debated the best way to wean patients from ventilators when acute respiratory failure has resolved. Two studies recently addressed this question, reaching seemingly conflicting conclusions (see Am J Resp Crit Care Med 1994; 150:896, and N Engl J Med 1995; 332:345, the latter reviewed in Journal Watch accession number 950228001). With no clear consensus, physicians are left to wonder which weaning method to use. The choice requires an understanding of the different modes of mechanical ventilation. Synchronized Intermittent Mandatory Ventilation (SIMV, often called IMV) and Assist Control (AC) are the modes most often used. In IMV, the ventilator provides a preset number of breaths per minute of a predetermined volu…