[Difficult weaning].

Abstract

Respiratory failure as a result of overload and/or reduced capacity of the respiratory muscles is the most common cause of unsuccessful weaning and the need for long term mechanical ventilation. Chronic obstructive pulmonary disease (COPD) is the most common underlying cause leading into long term mechanical ventilation. The most important clinical parameter for fatigue of the respiratory muscles is the rapid shallow breathing index. Other essential factors which impact weaning failure, are the underlying diseases (e. g. neuromuscular disease or heart failure), micro- and macro aspiration, malnutrition, anemia and obesity. A protocol based strategy to discontinue mechanical ventilation and the use of weaning predictors are helpful. Nonetheless the experienced physician is irreplacable in the weaning process. Reconditioning of the respiratory muscles is the main focus during weaning after long term mechanical ventilation and all therapeutic measures should be targeted to unload the fatiguing respiratory muscles. With the widely used assisted ventilation modes, the inspiratory work of breathing is still significantly increased. Only controlled mechanical ventilation (pressure- or volume controlled), which may also be applied to unsedated patients when individually adapted, offers the best possible relief and recovery of the respiratory muscles. Additional strategies, such as the balancing of anemia, reduction of the respiratory drive with i. e. morphine derivates, oxygen therapy during spontaneous-breathing trials and supine position for patients with obesity contribute to the recovery. Particularly patients with chronic lung diseases with hypercapnia benefit from the use of non invasive ventilation (NIV) after extubation to prevent postextubation failure and even after tracheostomy. However, NIV should only be applied under close monitoring and in cooperative patients, always considering the limits of the method. Dying under mechanical ventilation in the end stage illness is still a challenge for all involved persons. In the end stage of their disease for some patients it is possible to discontinue mechanical ventilation so they can spend the last period of their lives on a normal ward or even at home.