Weaning from Mechanical Ventilation
Section snippets
Pathophysiology of respiratory failure during weaning and extubation failure
Weaning from MV depends on the strength of respiratory muscles, the load applied to those muscles, and the respiratory drive to breathe. Respiratory failure may occur because of any of these. For example, muscular dystrophy (weakness of respiratory muscles), acute bronchospasm (increased respiratory load), or narcotic overdose (reduced central drive) all may lead to respiratory failure. In general, the etiology of unsuccessful weaning is the imbalance between the respiratory muscle pump and the
Timing for the initiation of weaning
Recognizing and treating the processes that caused the patient to go on the ventilator is the first goal in liberating him or her from MV. The complete resolution of the inciting event that led to respiratory failure does not need to be accomplished to start the process of weaning. Partial resolution of the cause of respiratory failure may be enough to be able to discontinue MV.
There are many reasons to attempt to get patients off MV as soon as possible. Common side effects of MV are
Weaning criteria and physiologic indices: key elements for successful weaning
The difficulty in integrating all the physiological parameters involved in weaning from MV has fueled a range of research to find the weaning parameters to determine readiness to wean. Conventional criteria for readiness to wean are relatively easy to use, but their sensitivity and specificity are relatively poor. These criteria include tidal volume (VT), minute ventilation (MV), vital capacity (VC), maximum voluntary ventilation (MVV), respiratory frequency, maximal inspiratory pressure as
Weaning modes of mechanical ventilations there a preferred technique?
Weaning from MV has been described as either a gradual decrease of ventilator support to allow liberation from the ventilator or determining when the patients will have the ability to be separated from the ventilator safely. Multiple different techniques have been proposed to facilitate the transition to spontaneous ventilation. The studies that have addressed this issue, however, have conflicting results. These studies focused on the impact of the weaning mode on the work of breathing, rather
Protocolized weaning from mechanical ventilation—the role of nonphysician health care professionals
Several studies have evaluated weaning parameters to identify patients who are ready for extubation and how to apply those parameters in a guideline or protocol for the weaning to be successful in the shortest possible time [2], [8], [9], [10]. Fig. 1 is an example of such a guideline. The initial step in any protocol-driven ventilator weaning is daily screening for readiness to wean using several weaning parameters. To do so, every appropriate patient in the ICU also should undergo a daily
Summary
MV is a life-sustaining therapy fraught with side effects. The successful removal of MV at any time is associated with a higher survival rate. Therefore, removing the patient from the ventilator as soon as possible is in the patient's best interest. The best approach to weaning patients from MV involves a team approach of all caregivers (physician, nurses, respiratory therapist, physical therapist, and nutritionists). The team uses a weaning protocol that gives the nurses and/or the respiratory
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What have we learned about weaning over the last five years?