Pressure support versus T-tube for weaning from mechanical ventilation in adults.

BACKGROUND: Mechanical ventilation is important in caring for patients with critical illness. Clinical complications, increased mortality, and high costs of health care are associated with prolonged ventilatory support or premature discontinuation of mechanical ventilation. Weaning refers to the process of gradually or abruptly withdrawing mechanical ventilation. The weaning process begins after partial or complete resolution of the underlying pathophysiology precipitating respiratory failure and ends with weaning success (successful extubation in intubated patients or permanent withdrawal of ventilatory support in tracheostomized patients). OBJECTIVES: To evaluate the effectiveness and safety of two strategies, a T-tube and pressure support ventilation, for weaning adult patients with respiratory failure that required invasive mechanical ventilation for at least 24 hours, measuring weaning success and other clinically important outcomes. SEARCH METHODS: We searched the following electronic databases: Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 6); MEDLINE (via PubMed) (1966 to June 2012); EMBASE (January 1980 to June 2012); LILACS (1986 to June 2012); CINAHL (1982 to June 2012); SciELO (from 1997 to August 2012); thesis repository of CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) (http://capesdw.capes.gov.br/capesdw/) (August 2012); and Current Controlled Trials (August 2012).We reran the search in December 2013. We will deal with any studies of interest when we update the review. SELECTION CRITERIA: We included randomized controlled trials (RCTs) that compared a T-tube with pressure support (PS) for the conduct of spontaneous breathing trials and as methods of gradual weaning of adult patients with respiratory failure of various aetiologies who received invasive mechanical ventilation for at least 24 hours. DATA COLLECTION AND ANALYSIS: Two authors extracted data and assessed the methodological quality of the included studies. Meta-analyses using the random-effects model were conducted for nine outcomes. Relative risk (RR) and mean difference (MD) or standardized mean difference (SMD) were used to estimate the treatment effect, with 95% confidence intervals (CI). MAIN RESULTS: We included nine RCTs with 1208 patients; 622 patients were randomized to a PS spontaneous breathing trial (SBT) and 586 to a T-tube SBT. The studies were classified into three categories of weaning: simple, difficult, and prolonged. Four studies placed patients in two categories of weaning. Pressure support ventilation (PSV) and a T-tube were used directly as SBTs in four studies (844 patients, 69.9% of the sample). In 186 patients (15.4%) both interventions were used along with gradual weaning from mechanical ventilation; the PS was gradually decreased, twice a day, until it was minimal and periods with a T-tube were gradually increased to two and eight hours for patients with difficult and prolonged weaning. In two studies (14.7% of patients) the PS was lowered to 2 to 4 cm H2O and 3 to 5 cm H2O based on ventilatory parameters until the minimal PS levels were reached. PS was then compared to the trial with the T-tube (TT).We identified 33 different reported outcomes in the included studies; we took 14 of them into consideration and performed meta-analyses on nine. With regard to the sequence of allocation generation, allocation concealment, selective reporting and attrition bias, no study presented a high risk of bias. We found no clear evidence of a difference between PS and TT for weaning success (RR 1.07, 95% CI 0.97 to 1.17, 9 studies, low quality of evidence), intensive care unit (ICU) mortality (RR 0.81, 95% CI 0.53 to 1.23, 5 studies, low quality of evidence), reintubation (RR 0.92, 95% CI 0.66 to 1.26, 7 studies, low quality evidence), ICU and long-term weaning unit (LWU) length of stay (MD -7.08 days, 95% CI -16.26 to 2.1, 2 studies, low quality of evidence) and pneumonia (RR 0.67, 95% CI 0.08 to 5.85, 2 studies, low quality of evidence). PS was significantly superior to the TT for successful SBTs (RR 1.09, 95% CI 1.02 to 1.17, 4 studies, moderate quality of evidence). Four studies reported on weaning duration, however we were unable to combined the study data because of differences in how the studies presented their data. One study was at high risk of other bias and four studies were at high risk for detection bias. Three studies reported that the weaning duration was shorter with PS, and in one study the duration was shorter in patients with a TT. AUTHORS' CONCLUSIONS: To date, we have found evidence of generally low quality from studies comparing pressure support ventilation (PSV) and with a T-tube. The effects on weaning success, ICU mortality, reintubation, ICU and LWU length of stay, and pneumonia were imprecise. However, PSV was more effective than a T-tube for successful spontaneous breathing trials (SBTs) among patients with simple weaning. Based on the findings of single trials, three studies presented a shorter weaning duration in the group undergoing PS SBT, however a fourth study found a shorter weaning duration with a T-tube.

Non-invasive positive pressure ventilation (CPAP or bilevel NPPV) for cardiogenic pulmonary oedema.

BACKGROUND: This is an update of a systematic review previously published in 2008 about non-invasive positive pressure ventilation (NPPV). NPPV has been widely used to alleviate signs and symptoms of respiratory distress due to cardiogenic pulmonary oedema. NPPV prevents alveolar collapse and helps redistribute intra-alveolar fluid, improving pulmonary compliance and reducing the pressure of breathing. OBJECTIVES: To determine the effectiveness and safety of NPPV in the treatment of adult patients with cardiogenic pulmonary oedema in its acute stage. SEARCH METHODS: We searched the following databases on 20 April 2011: CENTRAL and DARE, (The Cochrane Library, Issue 2 of 4, 2011); MEDLINE (Ovid, 1950 to April 2011); EMBASE (Ovid, 1980 to April 2011); CINAHL (1982 to April 2011); and LILACS (1982 to April 2011). We also reviewed reference lists of included studies and contacted experts and equipment manufacturers. We did not apply language restrictions. SELECTION CRITERIA: We selected blinded or unblinded randomised or quasi-randomised clinical trials, reporting on adult patients with acute or acute-on-chronic cardiogenic pulmonary oedema and where NPPV (continuous positive airway pressure (CPAP) or bilevel NPPV) plus standard medical care was compared with standard medical care alone. DATA COLLECTION AND ANALYSIS: Two authors independently selected articles and abstracted data using a standardised data collection form. We evaluated study quality with emphasis on allocation concealment, sequence generation allocation, losses to follow-up, outcome assessors, selective outcome reporting and adherence to the intention-to-treat principle. MAIN RESULTS: We included 32 studies (2916 participants), of generally low or uncertain risk of bias. Compared with standard medical care, NPPV significantly reduced hospital mortality (RR 0.66, 95% CI 0.48 to 0.89) and endotracheal intubation (RR 0.52, 95% CI 0.36 to 0.75). We found no difference in hospital length of stay with NPPV; however, intensive care unit stay was reduced by 1 day (WMD -0.89 days, 95% CI -1.33 to -0.45). Compared with standard medical care, we did not observe significant increases in the incidence of acute myocardial infarction with NPPV during its application (RR 1.24, 95% CI 0.79 to 1.95) or after (RR 0.70, 95% CI 0.11 to 4.26). We identified fewer adverse events with NPPV use (in particular progressive respiratory distress and neurological failure (coma)) when compared with standard medical care. AUTHORS' CONCLUSIONS: NPPV in addition to standard medical care is an effective and safe intervention for the treatment of adult patients with acute cardiogenic pulmonary oedema. The evidence to date on the potential benefit of NPPV in reducing mortality is entirely derived from small-trials and further large-scale trials are needed.

Non-invasive positive pressure ventilation (CPAP or bilevel NPPV) for cardiogenic pulmonary edema.

BACKGROUND: Non-invasive positive pressure ventilation (NPPV) has been widely used to alleviate signs and symptoms of respiratory distress due to cardiogenic pulmonary edema. NPPV prevents alveolar collapse and helps redistribute intra-alveolar fluid, improving pulmonary compliance and reducing the pressure of breathing. OBJECTIVES: To determine the effectiveness and safety of NPPV in the treatment of adult patients with cardiogenic pulmonary edema. SEARCH STRATEGY: We undertook a comprehensive search of the following databases in April 2005: CENTRAL, MEDLINE, EMBASE, CINAHL, DARE and LILACS. We also reviewed reference lists of included studies and contacted experts, equipment manufacturers, and the Cochrane Heart Group. We did not apply language restrictions. SELECTION CRITERIA: We selected blinded or unblinded randomized or quasi-randomized clinical trials, reporting on adult patients with acute or acute-on-chronic cardiogenic pulmonary edema and where NPPV (continuous positive airway pressure (CPAP)) and/or bilevel NPPV plus standard medical care was compared with standard medical care alone. DATA COLLECTION AND ANALYSIS: Two authors independently selected articles and abstracted data using a standardized data collection form. We evaluated study quality with emphasis on allocation concealment, adherence to the intention-to-treat principle and losses to follow-up. MAIN RESULTS: We included 21 studies involving 1,071 participants. Compared to standard medical care, NPPV significantly reduced hospital mortality (RR 0.6, 95% CI 0.45 to 0.84) and endotracheal intubation (RR 0.53, 95% CI 0.34 to 0.83) with numbers needed to treat of 13 and 8, respectively. We found no difference in hospital length of stay with NPPV, however, intensive care unit stay was reduced by 1 day (WMD -1.07 days, 95% CI -1.60 to -0.53). Compared to standard medical care, we did not observe significant increases in the incidence of acute myocardial infarction with NPPV during (RR 1.24, 95% CI 0.79 to 1.95) or after (RR 0.82, 95% CI 0.09 to 7.54) its application. AUTHORS' CONCLUSIONS: NPPV, especially CPAP, in addition to standard medical care is an effective and safe intervention for the treatment of adult patients with acute cardiogenic pulmonary edema.