Direct approach speeds ventilator weaning

By Eleanor McDermid, Senior medwireNews Reporter

Moving straight to unassisted breathing through a tracheostomy collar results in faster weaning than does a gradual reduction in pressure support among patients needing prolonged mechanical ventilation, shows a randomized trial in JAMA.

The two methods are widely used in clinical practice, say lead researcher Amal Jubran (Edward Hines Jr Veterans Affairs Hospital, Hines, Illinois, USA) and colleagues, but their relative efficacy "has undergone little or no scrutiny."

The 316 patients in the study were screened with unassisted breathing for 5 days, with those who failed the screen (ie, developed respiratory distress) entering the trial. Notably, effect of weaning method on speed was most striking among patients who tolerated the screen for at least 12 hours; they had a median weaning time of 20 versus 9 days with tracheostomy collar compared with pressure support, respectively.

The researchers say that patients who failed the screen early were generally sicker than those who tolerated it for longer, and suggest that, in the early-failure group, illness was a stronger determinant of the speed of weaning than was the weaning method.

Patients randomly assigned to the tracheostomy collar group were disconnected from the ventilator and allowed to breathe through the tracheostomy, unassisted, for up to 12 hours/day for the first 2 days, after which they were disconnected from the ventilator for up to 24 hours/day. In all, 53% of this group was successfully weaned, in a median of 15 days, with weaning defined as 5 full days of unassisted breathing.

The tracheostomy-collar group was weaned significantly faster than the patients in the pressure support group, of whom 45% achieved it, in a median of 19 days. Patients in this group had incremental reductions in pressure support, if tolerated, from an initial setting of 14 cm H₂O with a maximum reduction of 6 cm H₂O allowed in a single day. When patients could tolerate pressure support of less than 6 cm H₂O, ventilator disconnection was attempted.

"The faster pace of weaning with tracheostomy collar use may be related to its effect on clinical decision making," suggest Jubran et al. They say that unassisted breathing through a tracheostomy collar gives "a clear view of the patient's respiratory capabilities," whereas ventilator assistance may cloud clinicians' ability to judge what patients are capable of unaided.

"Accordingly, clinicians may accelerate the weaning process more in patients who perform unexpectedly well during a tracheostomy collar challenge than in patients for whom a low level of pressure support is being used," they say.

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