Sedation during weaning from mechanical ventilation.

Abstract

The transition from mechanical ventilation to spontaneous breathing in the intensive care unit is a two-stage process: weaning and extubation. Certain parameters require consideration before the commencement of weaning, namely respiratory function (both pulmonary gas exchange and respiratory muscle strength), cardiovascular status, stability of clinical condition, low metabolic demands, psychological factors and, possibly, patient collaboration. Appropriate sedation is crucial for successful weaning to keep the patient rested and to maintain the oxygen consumption and carbon dioxide production low. In this review, three types of patient are considered: patients having short-term ventilation after trauma or surgery, those having long-term ventilation for chronic pulmonary disease, and those with other associated severe organ dysfunction, such as heart failure. Strategies for weaning are outlined for each of these situations and the role of sedation is discussed. Making the transition from mechanical ventilation to unassisted spontaneous breathing can be a difficult process, particularly for those patients in the intensive care unit (ICU) requiring prolonged ventilatory assistance for severe respiratory failure secondary to: exacerbation of chronic obstructive airways disease (COAD) acute respiratory distress syndrome (ARDS) underlying diseases affecting cardiac function. This transition may be considered to comprise two separate stages, namely weaning and extubation. Weaning consists of preparation for spontaneous breathing supported and monitored by a mechanical ventilator and attendant monitoring of all the important vital parameters, while extubation marks the final switch to unsupported spontaneous breathing, which may be quite a big step for the patient. Important weaning parameters.