Noninvasive mechanical ventilation with average volume assured pressure support (AVAPS) in patients with chronic obstructive pulmonary disease and hypercapnic encephalopathy

Abstract

BackgroundNon-invasive mechanical ventilation (NIV) in patients with acute respiratory failure has been traditionally determined based on clinical assessment and changes in blood gases, with NIV support pressures manually adjusted by an operator. Bilevel positive airway pressure-spontaneous/timed (BiPAP S/T) with average volume assured pressure support (AVAPS) uses a fixed tidal volume that automatically adjusts to a patient’s needs. Our study assessed the use of BiPAP S/T with AVAPS in patients with chronic obstructive pulmonary disease (COPD) and hypercapnic encephalopathy as compared to BiPAP S/T alone, upon immediate arrival in the Emergency-ICU.MethodsWe carried out a prospective interventional match-controlled study in Guayaquil, Ecuador. A total of 22 patients were analyzed. Eleven with COPD exacerbations and hypercapnic encephalopathy with a Glasgow Coma Scale (GCS) <10 and a pH of 7.25-7.35 were assigned to receive NIV via BiPAP S/T with AVAPS. Eleven patients were selected as paired controls for the initial group by physicians who were unfamiliar with our study, and these patients were administered BiPAP S/T. Arterial blood gases, GCS, vital signs, and ventilatory parameters were then measured and compared between the two groups.ResultsWe observed statistically significant differences in favor of the BiPAP S/T + AVAPS group in GCS (P = .00001), pCO2 (P = .03) and maximum inspiratory positive airway pressure (IPAP) (P = .005), among others. However, no significant differences in terms of length of stay or days on NIV were observed.ConclusionsBiPAP S/T with AVAPS facilitates rapid recovery of consciousness when compared to traditional BiPAP S/T in patients with chronic obstructive pulmonary disease and hypercapnic encephalopathy.Trial registrationCurrent Controlled Trials application ref is ISRCTN05135218

Noninvasive Ventilation for Acute Hypercapnic Respiratory Failure: Is It the Same as in Hypercapnic Coma?—Reply

“…As we used exclusively ICU ventilators, inspiratory positive airway pressure, including pressure support and PEEP, reached 16.5 Ϯ 2.8 cm H 2 O in subjects who were comatose at admission, a value close to that reported in the abovementioned studies. 3,4 We agree that adjustment of an adequate pressure support level is the key setting to reverse hypercapnic coma, and we believe that our good results are due in part to our protocol of adjusting the pressure support level to target a minimal V T , as would average volume-assured pressure support. Altered consciousness at admission does not seem to increase the risk of NIV failure.…”

“…3 Dr Briones Claudett emphasizes that subjects with altered consciousness may require higher levels of pressure support than those with normal consciousness. To support this, Briones Claudett et al 4 recently found a faster recovery from hypercapnic encephalopathy using ventilatory mode with average volume-assured pressure support compared with pressure support ventilation during NIV due to higher levels of ventilatory assistance and larger tidal volumes (V T ).…”

“…Díaz et al 4 used BiPAP Vision or BiPAP S/T-D 30 (Philips Respironics, Murrysville, Pennsylvania), and inspiratory positive airway pressure (IPAP) was initially programmed at 12 cm H 2 O and increased every 4 h, with an IPAP in the first hour of 17 Ϯ 2 cm H 2 O. Briones Claudett et al 5 reported an IPAP baseline of 19.82 in the bi-level positive airway pressure spontaneous/timed (BPAP S/T) group with average volume-assured pressure support. Therefore, the use of pressure levels in this study in hypercapnic coma patients must be considered independently of the pressure levels used in patients with impaired sensory level that are without hypercapnic coma because levels may be below those routinely used in daily practice.…”

Noninvasive Ventilation for Acute Hypercapnic Respiratory Failure: Is It the Same as in Hypercapnic Coma?

“…Díaz et al 4 used BiPAP Vision or BiPAP S/T-D 30 (Philips Respironics, Murrysville, Pennsylvania), and inspiratory positive airway pressure (IPAP) was initially programmed at 12 cm H 2 O and increased every 4 h, with an IPAP in the first hour of 17 Ϯ 2 cm H 2 O. Briones Claudett et al 5 reported an IPAP baseline of 19.82 in the bi-level positive airway pressure spontaneous/timed (BPAP S/T) group with average volume-assured pressure support. Therefore, the use of pressure levels in this study in hypercapnic coma patients must be considered independently of the pressure levels used in patients with impaired sensory level that are without hypercapnic coma because levels may be below those routinely used in daily practice.…”

Non-invasive positive pressure ventilation offers greater improvement in COPD-related respiratory failure when combined with naloxone

“…NPPV refers to positive pressure ventilation that is not delivered via endotracheal or tracheostomy tube. In addition to treating acute respiratory failure due to COPD, with a success rate of 80-85% (Köhnlein et al, 2014;Elliott 2002;Wei et al, 2012;Halpin and Miravitlles, 2006), NPPV can reduce pain and treatment costs compared with conventional mechanical ventilation via an artificial airway (Briones Claudett et al, 2013). Indeed, it can effectively prevent and treat a blockage in the airway and proactively improve the independent ventilation function and diffusion capacity (Potts 2009;Schettino et al, 2008).…”