Non-invasive mechanical ventilation with average volume-assured pressure support. Results according to the aetiology of acute respiratory failure.

INTRODUCTION: Until now, the ventilatory strategy with BiPAP S/T plus average volume-assured pressure support (AVAPS) has not been evaluated for its use in the different types of acute respiratory failure (ARF). Consequently we report the results of the use of this ventilatory strategy in these clinical scenarios. MATERIAL AND METHODS: This is a single-centre prospective study. The subjects were categorised according to the type of ARF: (1) hypercapnic ARF: chronic obstructive pulmonary disease and bronchial asthma; and (2) hypoxaemic ARF: pneumonia, acute respiratory distress syndrome, congestive heart failure, and interstitial lung disease. Multiple logistic regression was used to determine predictors of non-invasive mechanical ventilation (NIV) failure (intubation). Further, in a subgroup of patients with de novo hypoxaemic ARF, analysis of variances with repeated measures was used to determine factors associated with NIV outcome. RESULTS: Sixty-eight subjects were included in this study. The NIV success rate was 69.1% and the mortality rate was 20.6%. A multivariate analysis showed that the number of affected lung quadrants on chest X-ray (OR: 4.23, 95% CI: 4.17-4.31; P < 0.001) and ARF precipitating disease (OR: 4.46, 95% CI: 4.43-4.51; P < 0.001) were determinants of NIV failure. In the hypoxaemic ARF subgroup (n = 58), significant differences in several parameters were found between patients with positive and negative outcomes. CONCLUSIONS: The use of BiPAP S/T - AVAPS in subjects with hypercapnic ARF is associated with a better outcome than in those with de novo hypoxaemic ARF.

Volume-assured pressure support mode plus pirfenidone as resuscitation therapy in patients with exacerbation of idiopathic pulmonary fibrosis.

INTRODUCTION: Treatment among advanced stage idiopathic pulmonary fibrosis is quite challenging, especially considering that no major evidence has been released about it. This case report demonstrates and discusses the benefit of non-invasive mechanical ventilation in volume-assured pressure support (AVAPS) mode plus pirfenidone based on the relief of apatient'ssymptoms in combination with high-resolution computed tomography (HRCT) evidence. MATERIAL AND METHODS: An 83-year-old female patient with multiple hospital admissions within a six-month period initially presented with cardiac symptoms which were later attributed to apossible exacerbation of her primary diagnosis, idiopathic pulmonary fibrosis. CONCLUSION: The addition of non-invasive mechanical ventilation in AVAPS mode plus pirfenidone can improve the survival rates even in patients with current exacerbations of acute respiratory failure due to idiopathic pulmonary fibrosis.

Use of noninvasive mechanical ventilation with pressure support guaranteed with average volume in de novo hypoxaemic respiratory failure. A pilot study.

BACKGROUND: This study was designed to determine the results associated with the use of noninvasive mechanical ventilation (NIV) using the BiPAP S/T-AVAPS ventilation strategy in subjects with mild to moderate de novohypoxaemicrespiratory failure. METHODS: This is a prospective study that includes subjects with de novohypoxaemic respiratory failure (not produced by acute exacerbations of COPD, chronic lung disease, or congestive heart failure) with mild to moderate PaO2/FiO2, who were admitted to the Intensive Care Unit (ICU) of Santa Maria Clinic in Guayaquil, Ecuador. Subjects were divided into two groups and compared according to their PaO2/FiO2: higher than 100 and up to 200 mm Hg (moderate ARDS) or between 200 and 300 mm Hg (mild ARDS) (both groups were ventilated with the BiPAP S/T-AVAPS strategy). A value of P < 0.05 was considered significant. RESULTS: A total of 38 subjects were analysed in this study. The total rate of intubation was 34.2% while the mortality rate was 28.9%. Significant differences were observed when comparing success versus failure in exhaled tidal volumes (P = 0.04), peak inspired pressure (P < 0.001), PaO2 (P < 0.001), SaO2 (P < 0.002), PaO2/FiO2 (P < 0.002), RR (P < 0.001), HR (P < 0.001), and inspiratory time (P = 0.029) measured at baseline and at 12-hour, 24-hour and 48-hour intervals. CONCLUSION: The BiPAP S/T-AVAPS ventilatory mode can be used in subjects with de novo hypoxaemic respiratory failure with special vigilance concerning exhaled tidal volumes and inspired pressure.

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

BACKGROUND: Non-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. METHODS: We 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. RESULTS: We observed statistically significant differences in favor of the BiPAP S/T + AVAPS group in GCS (P = .00001), pCO(2) (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. CONCLUSIONS: BiPAP 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 REGISTRATION: Current Controlled Trials application ref is ISRCTN05135218.

Noninvasive mechanical ventilation in patients with chronic obstructive pulmonary disease and severe hypercapnic neurological deterioration in the emergency room.

OBJECTIVES: The objective of this study was to assess the effectiveness of noninvasive motion ventilation (NIMV) in patients with chronic obstructive pulmonary disease (COPD), having infectious exacerbation and severe hypercapnic neurological dysfunction in the emergency room. DESIGN: This is a prospective interventional study. SETTING: The study setting was the emergency room at the Military Hospital in Guayaquil, Ecuador. PATIENTS: A total of 24 patients were studied. Twelve patients had acute exacerbation of their chronic obstructive pulmonary disease: they presented at the emergency room with severe neurological dysfunction, with a Glasgow Coma Scale (GCS) score of less than 8 and a pH of less than 7.25. These patients were compared with 12 controls who were being treated with invasive mechanical ventilation (IMV), who were then matched according to their GCS scores, pH status, Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, and age. INTERVENTIONS: We evaluated the effectiveness and safety of applying a ventilatory strategy based on a biphasic positive airway pressure protocol in the emergency room. MEASUREMENTS AND RESULTS: The pH, PCO2, and GCS scores, measured during the first 3 h, were predictors of success for the application of NIMV treatment (P<0.05). Mortality was 33.3 and 16.7% for the IMV and the NIMV groups, respectively (P=0.01). Days of IMV were 5.60+/-1.2 versus 3.6+/-1.1 for NIMV (P=0.006). Days of hospitalization were 11.1+/-4.7 for the IMV group and 6.5+/-1.9 for the NIMV group (P=0.001). The cumulative survival rates at 6 months were 71.4 and 80% for the IMV and NIMV groups, respectively (P=0.80). CONCLUSION: We consider that severe neurological dysfunction and pH of less than 7.25 do not constitute absolute contraindications to the use of NIMV. This kind of management can be implemented in the emergency room with favorable results.