Acute respiratory failure requiring mechanical ventilation in severe chronic obstructive pulmonary disease (COPD)

Comparison of high flow nasal cannula with noninvasive ventilation in chronic obstructive pulmonary disease patients with hypercapnia in preventing postextubation respiratory failure: A pilot randomized controlled trial

High flow nasal cannula (HFNC) has been shown to improve extubation outcomes in patients with hypoxemia, but the role of HFNC in weaning patients with chronic obstructive pulmonary disease (COPD) with hypercapnia from invasive ventilation is unclear. We compared the effects of HFNC to noninvasive ventilation (NIV) on postextubation vital signs and arterial blood gases (ABGs) among patients with COPD. Other outcomes included comfort scores, need for bronchoscopy, use of pulmonary medications, and chest physiotherapy. Forty-two COPD patients who had persistent hypercapnia at extubation were assigned randomly to receive HFNC (22) or NIV (20). Twenty patients in each group were enrolled for per-protocol analysis with regard to primary outcomes. Vital signs and ABGs before extubation were similar between groups. At 3 hr after extubation, pH in the NIV group was lower than HFNC group (7.42 ± 0.06 vs. 7.45 ± 0.05, p = 0.01). At 24 hr after extubation, patients' mean arterial pressure (82.97 ± 9.04 vs. 92.06 ± 11.11 mmHg, p = 0.05) and pH (7.42 ± 0.05 vs. 7.46 ± 0.03, p = 0.05) in the NIV group were lower than in the HFNC group. No significant differences were found at 48 hr after extubation. In the HFNC group, comfort scores were better (3.55 ± 2.01 vs. 5.15 ± 2.28, p = 0.02) and fewer patients needed bronchoscopy for secretion management within 48 hr after extubation (2/22 vs. 9/20, p = 0.03). HFNC is a potential alternative to NIV to wean hypercapnic COPD patients with regard to vital signs and ABGs, HFNC improved patients' comfort and secretion clearance.

New modalities for non-invasive positive pressure ventilation: A review article

Efficiency of non-invasive positive pressure ventilation in the treatment of respiratory failure has been shown in many published studies. In this review article, we introduced new modalities of non-invasive ventilation (NIV), clinical settings in which NIV can be used and a practical summary of the latest official guidelines published by the European Respiratory Clinical Practice. Clinical trials and review articles in four databases up to 25 February 2018 about new modalities of non-invasive positive pressure ventilation were reviewed. Commonly used modalities for treatment of respiratory failure include: CPAP (continuous positive airway pressure) and BiPAP (bilevel positive airway pressure) or NIPSV (noninvasive pressure support ventilation). The limitations of the BiPAP method are the trigger and cycle asynchrony, inadequate volume delivery and increased respiratory rate. Newer methods, such as adaptive servo-ventilation, have been developed to treat central and complex sleep apnea and the NAVA (neutrally adjusted ventilatory assist) to improve the trigger and cycle asynchrony. In the proportional assist ventilation, unlike the pressure support ventilation, with increased patient effort (flow) the tidal volume increases and it prevents the increase in the respiratory rate and respiratory distress. High-flow nasal cannula is a non-invasive technique that does not provide respiratory support, but provides a mixture of oxygen to the patient. The use of non-invasive pursed-lip breathing ventilation in chronic obstructive pulmonary disease (COPD) patients reduces dyspnea (decreases respiratory rate) and increases blood oxygen saturation. New modalities of NIV improve patient comfort and patient-ventilator interactions, and are recommended in patients with respiratory failure.

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.