Respiratory factors in weaning from mechanical ventilatory support

Weaning, or the gradual reduction in partial ventilatory support, is required in only the minority of patients receiving mechanical ventilatory support (those who need prolonged ventilation support, generally more than 72 hours). Weaning techniques involve muscle reloading and generally require intact ventilatory drive, reasonable oxygenation drive, and reasonable oxygenation before they can be initiated. Weaning is best monitored by assessing load-tolerance, which is best accomplished by assessing the ventilatory pattern. Reloading techniques either involve allowing spontaneous unassisted breaths (as T-piece trials or as breaths interspersed with intermittent volume-assisted breaths) or providing partial support of every spontaneous effort through a delivered inspiratory pressure-assist. Different effects on load characteristics and ventilator synchrony can be seen with different modes. Although these effects may affect outcome, disease resolution is generally the rate-limiting step in weaning and the reason why only 50% to 60% of ventilator-dependent patients who need weaning are ever successfully withdrawn from the ventilator.

Duke Scholars

Author Neil Ross MacIntyre Jr. Medicine, Pulmonary, Allergy, and Critical Care Medicine