Ventilator Weaning

Fifty preterm infants weighing 1200 g or more with clinical and radiographic evidence of respiratory distress syndrome, requiring both mechanical ventilation and exogenous surfactant replacement, were randomly allocated to receive either volume controlled ventilation or time cycled, pressure limited ventilation. Tidal volume delivery in each group was deliberately controlled at 5-8 ml/kg so that the only difference between the two groups was the ventilatory modality, the manner in which tidal volume was delivered. The rest of the ventilatory management and clinical care was done according to protocol. The two modes of ventilation were compared by determining the time required to achieve pre-determined success criteria, based on either the alveolar-arterial oxygen gradient or the mean airway pressure as a standard against which the speed of weaning could be objectively assessed. Infants randomised to volume controlled ventilation met success criteria sooner and had a shorter duration...

The primary objective of this clinical trial of patients on mechanical ventilation was to determine if a weaning protocol implemented solely by nurses could reduce the weaning time relative to usual care (UC). This study is a prospective, randomized, controlled trial conducted from January 2007 to January 2009 that compared protocol-based weaning (PBW) with UC. A total of 122 patients who received invasive ventilation in the medical ICU of the Asan Medical Center were examined. Nurses operated the mechanical ventilators according to a predesigned ventilator-weaning protocol for the PBW group (n = 61), and intensive care unit (ICU) physicians managed weaning in the UC group (n = 61). There were no significant differences in the 2 groups at baseline. The number of patients who successfully discontinued mechanical ventilation was similar in the 2 groups (PBW, 46 patients, 75.4%; UC, 47 patients, 77.0%; P = .832). The weaning time was 47 hours (interquartile range, 24-168 hours) in the UC group and 25 hours (interquartile range, 5.75-134 hours) in the PBW group (P = .010). The weaning protocol administered by the nurses was safe and reduced the weaning time from mechanical ventilation in patients who were recovering from respiratory failure.

Adaptive support ventilation (ASV) is a closed loop mode of mechanical ventilation (MV) that provides a target minute ventilation by automatically adapting inspiratory pressure and respiratory rate with the minimum work of breathing for the patient. The aim of this study was to determine the effect of ASV on total MV duration when compared to Pressure Assist/Control Ventilation (P-ACV). Adult medical patients intubated and mechanically ventilated for more than 24 hours in a medical ICU were randomized either to ASV or P-ACV. Sedation and medical treatment were standardized for each group. Primary outcome was the total MV duration. Secondary outcomes were the weaning duration, number of manual settings of the ventilator and weaning success rates. Two hundred and twenty nine patients were included. Median MV duration until weaning, weaning and total MV duration were significantly shorter in the ASV group [67 (43-94) vs. 92 (61-165) hours, p= 0.003; 2 (2-2) vs. 2 (2-80) hours, p=0.001 ...

Background: In patients with acute exacerbations of chronic obstructive pulmonary disease, mechanical venti­ lation is often needed. The rate of weaning failure is high in these patients, and prolonged mechanical ventilation increases intubation-associated complications. Objective: To determine whether noninvasive ventila­ tion improves the outcome of weaning from invasive me­ chanical ventilation. Design: Multicenter, randomized trial. Setting: Three respiratory intensive care

Ventilator-associated pneumonia is the most frequent intensive care unit (ICU)-related infection in patients requiring mechanical ventilation. In contrast to other ICU-related infections, which have a low mortality rate, the mortality rate for ventilator-associated pneumonia ranges from 20% to 50%. These clinically significant infections prolong duration of mechanical ventilation and ICU length of stay, underscoring the financial burden these infections impose on the health care system. The causes of ventilator-associated pneumonia are varied and differ across different patient populations and different types of ICUs. This varied presentation underscores the need for the intensivist treating the patient with ventilator-associated pneumonia to have a clear knowledge of the ambient microbiologic flora in their ICU. Prevention of this disease process is of paramount importance and requires a multifaceted approach. Once a diagnosis of ventilator-associated pneumonia is suspected, early broad-spectrum antibiotic administration decreases morbidity and mortality and should be based on knowledge of the sensitivities of common infecting organisms in the ICU. De-escalation of therapy, once final culture results are available, is necessary to minimize development of resistant pathogens. Duration of therapy should be based on the patient's clinical response, and every effort should be made to minimize duration of therapy, thus further minimizing the risk of resistance.

For most mechanically ventilated patients, weaning can be accomplished quickly and easily. However, there is a smaller group of ventilated patients who fail to wean and remain ventilator-dependent. These patients account for a significant amount of health care costs and pose a great challenge for clinicians. Detailed knowledge of the etiology and pathophysiology of weaning failure is very important for the “treatment” of difficult to wean patients, and is thoroughly presented in this article. Based on this physiological background, strategies and techniques are proposed that are useful for the gradual transition to spontaneous ventilation.

Weaning from mechanical ventilation represents one of the main challenges facing ICU physicians. Difficult weaning affects about 25% of critical patients undergoing mechanical ventilation. Its duration correlates on one hand with pathophysiological aspects of the underlying disease and, on the other hand, with other factors such as the development of neuromyopathy of the critically ill patient, prolonged use of sedative-hypnotic drugs and, most of all, physicians' reluctance to identify the correct timing of therapeutic steps for weaning and subsequent extubation. The goal of adopting weaning protocols is to overcome problems due to an exclusively clinical opinion. Protocols have to be used together with daily clinical evaluation of the patient and the procedure must be carried out by an ICU team of both medical and nursing staff. Attempts to wean a patient from a ventilator and extubate him should be made through a spontaneous breathing trial (SBT) with T-tube or pressure suppo...