National survey of methods and criteria used for weaning from mechanical ventilation.

A national survey of hospital-based respiratory care departments was conducted to quantitate the use of various techniques and criteria employed to facilitate weaning of patients from mechanical ventilatory support. Responses were partitioned into private, nonprivate and university/university-affiliated institutions with further subdivision into bed-size groups of not more than 50 beds, 51 to 150 beds, 151 to 300 beds, and not less than 301 beds. Intermittent mandatory ventilation (IMV) was the most frequently used weaning technique in 90.2% of the responding hospitals. IMV was also listed as the primary mode of mechanical ventilatory support (71.6%). IMV to a T-tube system was the most common weaning protocol in nonuniversity hospitals. IMV to 3 to 5 cm H2O continuous positive airway pressure and IMV to T-tube were equally utilized in university/university-affiliated centers. PaCO2 was identified the most often (20.7%) and physiologic deadspace ratio the least often (2.5%) as a weaning criterion. We conclude that IMV is probably the most widely practiced weaning technique and that a variety of weaning criteria were employed.