Predictors of survival after prolonged weaning from mechanical ventilation.

PURPOSE: Weaning from mechanical ventilation is a key component of intensive care treatment; however, this process may be prolonged as some patients require care at specialised centres. Current data indicate that weaning from invasive mechanical ventilation is successful in approximately 65% of patients; however, data on long-term survival after discharge from a weaning centre are limited. MATERIALS AND METHODS: We analysed predictors of survival among 597 patients (392 men, mean age 68 ± 11) post-discharge from a specialised German weaning centre. RESULTS: Complete weaning from mechanical ventilation was achieved in 407 (57.8%) patients, and 106 patients (15.1%) were discharged with non-invasive ventilation; thus, prolonged weaning was successful in 72.9% of the patients. The one-year and five-year survival rates post-discharge were 66.5% and 37.1%, respectively. Age, duration of mechanical ventilation, certain clusters of comorbidities, and discharged with mechanical ventilation significantly influenced survival (p < .001). Completely weaned patients who were discharged with a tracheostomy had a significantly reduced survival rate than did those who were completely weaned and discharged with a closed tracheostomy (p = .004). CONCLUSIONS: The identified predictors of survival after prolonged weaning could support therapeutic strategies during patients' intensive care unit stay. Patients should be closely monitored after discharge from a weaning centre.

Exercise and fluid challenge during right heart catheterisation for evaluation of dyspnoea.

This prospective study compared exercise test and intravenous fluid challenge in a single right heart catheter procedure to detect latent diastolic heart failure in patients with echocardiographic heart failure with preserved ejection function. We included 49 patients (73% female) with heart failure with preserved ejection function and pulmonary artery wedge pressure ≤15 mmHg. A subgroup of 26 patients had precapillary pulmonary hypertension. Invasive haemodynamic and gas exchange parameters were measured at rest, 45° upright position, during exercise, after complete haemodynamic and respiratory recovery in lying position, and after rapid infusion of 500 mL isotonic solution. Most haemodynamic parameters increased at both exercise and intravenous fluid challenge, with the higher increase at exercise. Pulmonary vascular resistance decreased by -0.21 wood units at exercise and -0.56 wood units at intravenous fluid challenge (p = 0.3); 20% (10 of 49) of patients had an increase in pulmonary artery wedge pressure above the upper limit of 20 mmHg at exercise, and 20% above the respective limit of 18 mmHg after intravenous fluid challenge. However, only three patients exceeded the upper limit of pulmonary artery wedge pressure in both tests, i.e. seven patients only at exercise and seven other patients only after intravenous fluid challenge. In the subgroup of pulmonary hypertension patients, only two patients exceeded pulmonary artery wedge pressure limits in both tests, further five patients at exercise and four patients after intravenous fluid challenge. A sequential protocol in the same patient showed a significantly higher increase in haemodynamic parameters at exercise compared to intravenous fluid challenge. Both methods can unmask diastolic dysfunction at right heart catheter procedure, but in different patient groups.

Right Heart Catheterization During Exercise in Patients with COPD-An Overview of Clinical Results and Methodological Aspects.

While right heart catheterization (RHC) at rest is the gold standard to assess pulmonary hemodynamics in patients with chronic obstructive pulmonary disease (COPD) and pulmonary hypertension (PH), the invasive measurement of exercise hemodynamics is less well established in this group. Since exercise hemodynamics are increasingly recognized as important clinical information in patients with PH, our goal was to review the literature in this field to provide a basis for clinical use, further studies, and future recommendations. We identified 69 studies (published since 1968) reporting RHC data in 2819 patients with COPD, of whom 2561 underwent exercise testing. Few studies simultaneously measured gas exchange during exercise. Overall, these studies showed large variations in the patient populations and research questions studied and the methods and definitions employed. Despite these limitations, the data consistently demonstrated the presence of precapillary PH at rest in up to 38% of patients with COPD. With exercise, a relevant proportion of patients developed an abnormal hemodynamic response, depending on the definition used. Furthermore, some studies assessed right ventricular function during exercise and showed a blunted increase in right ventricular ejection fraction. Drug effects and the impact of interventional procedures were also studied. Again, due to large variations in the patients studied and the methods used, firm conclusions are difficult to derive. Despite the limitations of this dataset, several recommendations with respect to technical aspects (body position, exercise protocol, and data acquisition) can be inferred for this challenging patient population and may be helpful for further studies or recommendations.