sábado, 3 de mayo de 2014

Ventilación mecánica/Mechanical ventilation

La ventilación no invasiva como estrategia de destete de ventilación mecánica en adultos con insuficiencia respiratoria: una revisión sistemática Cochrane

Noninvasive ventilation as a weaning strategy for mechanical ventilation in adults with respiratory failure: a Cochrane systematic review.
Burns KE, Meade MO, Premji A, Adhikari NK.
CMAJ. 2014 Feb 18;186(3):E112-22. doi: 10.1503/cmaj.130974. Epub 2013 Dec 9.
BACKGROUND: Noninvasive ventilation has been studied as a means of reducing complications among patients being weaned from invasivemechanical ventilation. We sought to summarize evidence comparing noninvasive and invasive weaning and their effects on mortality. METHODS: We identified relevant randomized and quasirandomized trials through searches of databases, conference proceedings and grey literature. We included trials comparing extubation and immediate application of noninvasive ventilation with continued invasive weaning in adults onmechanical ventilation. Two reviewers each independently screened citations, assessed trial quality and abstracted data. Our primary outcome was mortality. RESULTS: We identified 16 trials involving 994 participants, most of whom had chronic obstructive pulmonary disease (COPD). Compared with invasive weaning, noninvasive weaning significantly reduced mortality (risk ratio [RR] 0.53, 95% confidence interval [CI] 0.36 to 0.80), weaning failures (RR 0.63, 95% CI 0.42 to 0.96), ventilator-associated pneumonia (RR 0.25, 95% CI 0.15 to 0.43), length of stay in the intensive care unit (mean difference [MD] -5.59 d, 95% CI -7.90 to -3.28) and in hospital (MD -6.04 d, 95% CI -9.22 to -2.87), and total duration of mechanical ventilation (MD -5.64 d, 95% CI -9.50 to -1.77). Noninvasive weaning had no significant effect on the duration of ventilation related to weaning, but significantly reduced rates of tracheostomy (RR 0.19, 95% CI 0.08 to 0.47) and reintubation (RR 0.65, 95% CI 0.44 to 0.97). Mortality benefits were significantly greater in trials enrolling patients with COPD than in trials enrolling mixed patient populations (RR 0.36 [95% CI 0.24 to 0.56] v. RR 0.81 [95% CI 0.47 to 1.40]). INTERPRETATION: Noninvasive weaning reduces rates of death and pneumonia without increasing the risk of weaning failure or reintubation. In subgroup analyses, mortality benefits were significantly greater in patients with COPD.

Justificación y diseño del estudio ViPS - soporte de presión variable para el destete de la ventilación mecánica: protocolo del estudio multicéntrico internacional para un ensayo controlado aleatorio abierto.

Rationale and study design of ViPS - variable pressure support for weaning from mechanical ventilation: study protocol for an international multicenter randomized controlled open trial.

Kiss T, Güldner A, Bluth T, Uhlig C, Spieth PM, Markstaller K, Ullrich R, Jaber S, Santos JA, Mancebo J, Camporota L, Beale R, Schettino G, Saddy F, Vallverdú I,Wiedemann B, Koch T, Schultz MJ, Pelosi P, de Abreu MG1.

Trials. 2013 Oct 31;14:363. doi: 10.1186/1745-6215-14-363.


BACKGROUND: In pressure support ventilation (PSV), a non-variable level of pressure support is delivered by the ventilator when triggered by the patient. In contrast, variable PSV delivers a level of pressure support that varies in a random fashion, introducing more physiological variability to therespiratory pattern. Experimental studies show that variable PSV improves gas exchange, reduces lung inflammation and the mean pressure support, compared to non-variable PSV. Thus, it can theoretically shorten weaning from the mechanical ventilator. METHODS/DESIGN: The ViPS (variable pressure support) trial is an international investigator-initiated multicenter randomized controlled open trial comparing variable vs. non-variable PSV. Adult patients on controlled mechanical ventilation for more than 24 hours who are ready to be weaned are eligible for the study. The randomization sequence is blocked per center and performed using a web-based platform. Patients are randomly assigned to one of the two groups: variable PSV or non-variable PSV. In non-variable PSV, breath-by-breath pressure support is kept constant and targeted to achieve a tidal volume of 6 to 8 ml/kg. In variable PSV, the mean pressure support level over a specific time period is targeted at the same mean tidal volume as non-variable PSV, but individual levels vary randomly breath-by-breath. The primary endpoint of the trial is the time to successful weaning, defined as the time from randomization to successful extubation. DISCUSSION: ViPS is the first randomized controlled trial investigating whether variable, compared to non-variable PSV, shortens the duration ofweaning from mechanical ventilation in a mixed population of critically ill patients. This trial aims to determine the role of variable PSV in the intensive care unit.

Los niveles de hemoglobina y el resultado del destete de la ventilación mecánica en pacientes difíciles de destete: un estudio de cohorte retrospectivo.

Hemoglobin levels and weaning outcome of mechanical ventilation in difficult-to-wean patients: a retrospective cohort study.
Lai YC, Ruan SY, Huang CT, Kuo PH, Yu CJ.

PLoS One. 2013 Aug 28;8(8):e73743. doi: 10.1371/journal.pone.0073743. eCollection 2013.


INTRODUCTION: The effect of hemoglobin levels on the weaning outcomes of mechanically ventilated patients remains under debate, particularly for the patients with difficult weaning. This study aims to evaluate the effect of hemoglobin levels on weaning outcomes in difficult-to-wean patients. METHODS: This retrospective cohort study was conducted in a university-affiliated teaching hospital in Taiwan. Patients who fulfilled the criteria of difficult weaning were enrolled. Medical records were reviewed to obtain data on hemograms, biochemistry tests, transfusion records, comorbidities and weaning outcome. The association between hemoglobin levels and 30-day weaning outcomes was evaluated using a logistic regression model. RESULTS: A total of 751 patients received mechanical ventilation during the study period, 138 of whom fulfilled the criteria of difficult weaning. Compared with the patients whose hemoglobin was <8 g/dL, those with higher hemoglobin levels were more likely to be successfully weaned (odds ratio [OR], 3.69; 95% CI, 1.22-11.15 for hemoglobin 8-10 g/dL and OR, 4.16, 95% CI, 1.30-13.29 for hemoglobin >10 g/dL). Multivariate analysis showed that the odds ratio for weaning success remained significant for hemoglobin levels of 8-10 g/dL (adjusted OR, 3.3; 95% CI, 1.07-10.15) with borderline significance for hemoglobin level > 10 g/dL (adjusted OR, 2.95, 95% CI, 0.88-9.96). CONCLUSIONS: Hemoglobin level is independently associated with weaning outcome in difficult-to-wean patients. Further studies are needed to evaluate whether a restrictive transfusion trigger for acute critical illness is also appropriate for such patients.


Anestesiología y Medicina del Dolor
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