Controversies in Weaning from Mechanical Ventilation

Abstract

Invasive mechanical ventilation can successfully support the patient with acute respiratory failure, but it is associated with considerable risks. Numerous complications of invasive mechanical ventilation have been identified, and these may contribute to increased mortality. Therefore after clinical improvement has occurred, considerable emphasis is placed on expeditiously freeing the patient from the ventilator. This process of getting a patient off mechanical ventilation has been variably termed weaning, liberation, or discontinuation (terms which may be used interchangeably), and can be further divided into “readiness testing” and “progressive withdrawal.” Over the last decade, new developments in our understanding of the process of weaning have provided investigators with the tools to address a number of key questions: How should readiness for weaning (and trials of spontaneous breathing) be determined? What is the role of weaning parameters in deciding when to initiate the weaning process? What is the best mode for conducting a spontaneous breathing trial and how should the patient be monitored? What are the mechanisms for weaning (and spontaneous breathing trial) failure? What is the best technique to facilitate progressive withdrawal? What other factors can facilitate liberation from mechanical ventilation? What are the risks of extubation failure and how can extubation outcome best be predicted? What is the role for protocols in facilitating weaning from mechanical ventilation?.

Early extubation after congenital heart surgery

“…Study of the Neirotti et al (15) showed, as well as our research, that failure to thrive is one of the risk factor of prolonged ventilation [95%CI (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)]. …”

“…Early extubation was defined as mechanical ventilation in period shorter than 24 hours (practically shorter than 24 hours, usually 4-8 hours) (1)(2)(3)(4). Determination of the optimal moment for extubation is based on clinically and laboratory factors, that indicates possibility of appropriate blood gas exchange during spontaneously breathing.…”

Noninvasive Monitoring of Cardiac Output During Weaning From Mechanical Ventilation: A Pilot Study

“…Alternatively, the ability to augment cardiac output during an unsuccessful weaning trial may indicate noncardiac causes, such as muscle weakness, malnutrition, increased resistive or elastic loads, endocrinopathies, or anxiety, as the cause of the lack of success. 18,20,21 Previous research 6 indicates that a major proportion of patients who have an unsuccessful SBT have associated cardiac dysfunction. Using an invasive measure of intravascular pressure, Jubran et al 22 compared the continuous recording of mixed venous oxygen saturation in patients whose weaning trial was successful with that of patients whose trial was unsuccessful.…”

Avaliação da relação entre espaço morto e volume corrente como índice preditivo de falha de extubação

“…This is not yet entirely possible, according to many authors and medical associations. 7,8 Over recent years, many different controlled studies of adult patients have been conducted in attempts to identify objective and precise parameters and criteria that can determine the most suitable moment for withdrawing the respirator and performing extubation. Even with experienced medical teams, routine application of the clinical and laboratory criteria indicative of successful weaning still results in significant extubation failure and reintubation rates.…”