Pressure-support ventilation or T-piece spontaneous breathing trials for patients with chronic obstructive pulmonary disease - A randomized controlled trial.

BACKGROUND: Little is known about the best strategy for weaning patients with chronic obstructive pulmonary disease (COPD) from mechanical ventilation. Spontaneous breathing trials (SBT) using a T-piece or pressure-support ventilation (PSV) have a central role in this process. Our aim was to compare T-piece and PSV SBTs according to the duration of mechanical ventilation (MV) in patients with COPD. METHODS: Patients with COPD who had at least 48 hours of invasive MV support were randomized to 30 minutes of T-piece or PSV at 10 cm H2O after being considered able to undergo a SBT. All patients were preemptively connected to non-invasive ventilation after extubation. Tracheostomized patients were excluded. The primary outcome was total invasive MV duration. Time to liberation from MV was assessed as secondary outcome. RESULTS: Between 2012 and 2016, 190 patients were randomized to T-piece (99) or PSV (91) groups. Extubation at first SBT was achieved in 78% of patients. The mean total MV duration was 10.82 ± 9.1 days for the T-piece group and 7.31 ± 4.9 days for the PSV group (p < 0.001); however, the pre-SBT duration also differed (7.35 ± 3.9 and 5.84 ± 3.3, respectively; p = 0.002). The time to liberation was 8.36 ± 11.04 days for the T-piece group and 4.06 ± 4.94 for the PSV group (univariate mean ratio = 2.06 [1.29-3.27], p = 0.003) for the subgroup of patients with difficult or prolonged weaning. The study group was independently associated with the time to liberation in this subgroup. CONCLUSIONS: The SBT technique did not influence MV duration for patients with COPD. For the difficult/prolonged weaning subgroup, the T-piece may be associated with a longer time to liberation, although this should be clarified by further studies. TRIAL REGISTRATION: ClinicalTrials.gov NCT01464567, at November 3, 2011.

Underfeeding versus full enteral feeding in critically ill patients with acute respiratory failure: a systematic review with meta-analysis of randomized controlled trials.

INTRODUCTION: Although guidelines emphasize that the provision of enteral nutrition (EN) should be as close as the patient's needs, prospective studies question this strategy. OBJECTIVE: To compare the effect of two EN strategies (underfeeding versus full-feeding) on ICU and overall mortality (hospital mortality or 60-day mortality) and length of stay (LOS), duration of mechanical ventilation (MV), infectious complications, and gastrointestional tolerability in ICU patients. METHODS: Random effects meta-analysis of randomized controlled trials (RCT). Our search covered MEDLINE, EMBASE, SCOPUS and CENTRAL databases until May 2015. Underfeeding was assigned into to two different groups according to the level of energy intake achieved (moderate feeding 46-72% and trophic feeding 16-25%) for subgroup analysis. RESULTS: Five RCTs were included among the 904 studies retrieved (n=2432 patients). No difference was found in overall mortality when all five studies were combined. In the subgroup analysis, moderate feeding (three studies) showed lower mortality compared with full-feeding (RR 0.82;95%CI,0.68-0.98;I2 0% p=0.59 for heterogeneity). No differences were found for ICU mortality, ICU and hospital LOS, duration of MV, and infectious complications. Underfeeding showed lower occurrence of GI signs and symptoms except for aspiration and abdominal distention. CONCLUSIONS: This meta-analysis found no differences in ICU and overall mortality, ICU and hospital LOS, duration of MV, and infectious complications between underfeeding and full-feeding. The subgroup analysis showed lower overall mortality among patients receiving moderate underfeeding. This result should be cautiously interpreted due to the limitations of the small number of studies analyzed and their methodology.

Increasing pressure support does not enhance secretion clearance if applied during manual chest wall vibration in intubated patients: a randomised trial.

QUESTIONS: What is the effect of increasing pressure support during the application of manual chest wall compression with vibrations for secretion clearance in intubated patients in intensive care? DESIGN: A randomised trial with concealed allocation, assessor blinding and intention-to-treat analysis. PARTICIPANTS: 66 patients receiving mechanical ventilation for greater than 48 hours. INTERVENTION: All participants were positioned supine in bed with the backrest elevated 30 degrees. The experimental group received manual chest wall compression with vibrations during which their pressure support ventilation was increased by 10 cm H(2)O over its existing level. The control group received manual chest wall compression with vibrations but no adjustment of the ventilator settings. Both groups then received airway suction. OUTCOME MEASURES: The primary outcome was the weight of the aspirate. Secondary outcomes were pulmonary and haemodynamic measures and oxygenation. RESULTS: Although both treatments increased the weight of the aspirate compared to baseline, the addition of increased pressure support during manual chest wall compression with vibrations did not significantly increase the clearance of secretions, mean between-group difference in weight of the aspirate 0.4 g, 95% CI -0.5 to 1.4. Although several other measures also improved in one or both groups with treatment, there were no significant differences between the groups for any of the secondary outcomes. CONCLUSION: Although increasing pressure support has previously been shown to increase secretion clearance in intubated patients, the current study did not show any benefits when it was added to chest wall compression with vibrations. TRIAL REGISTRATION: NCT01155648.

Experimental ventilator-associated pneumonia: distribution of lung infection and consequences for lung aeration.

Ventilator-associated pneumonia (VAP) has been described in humans and in experimental animals. The most severe lesions are located in dependent lung segments along a sterno-vertebral axis, however the cephalocaudal distribution of lung infection remains unknown. We used an experimental model to evaluate the distribution of lung infection, considering its anteroposterior and cephalocaudal gradient, and its impact on lung aeration. Ten healthy domestic piglets were anesthetized, paralyzed and mechanically ventilated for 59 hours in the prone position. At the end of the experiment they were sacrificed and their lungs were fixed. Six segments were analyzed: a non-dependant (ND) and a dependant (D) segment of the upper (UL), middle (ML) and lower (LL) lobes. The presence of healthy lung or of histological infectious lesions was analyzed with a semi-quantitative method. The regional distribution of lung infection was compared between upper, middle and lower lobes, as well as between dependant and non-dependant regions. The presence of infectious lesions was correlated with measurements of lung aeration. Nine of the ten piglets developed VAP. Infectious lesions were distributed along a sterno-vertebral and a cephalocaudal gradient; the lower and middle lobes were more frequently infected than the upper lobes. There was an inverse correlation (R= - 0.902) between the development of lung lesions and lung aeration. In conclusion, VAP was a frequent complication in healthy mechanically ventilated piglets, showing an anteroposterior as well as a cephalocaudal gradient. As expected, development of lung infection was accompanied by a corresponding loss of aeration.