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.

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.

Ventilación mecánica no invasiva en pacientes inmunodeprimidos hematológicos. Análisis sistemático de la literatura / Noninvasive mechanical ventilation in immunosuppressed patients hematology. Systematic analysis of the literature

La Ventilación No Invasiva con Presión Positiva (NIPPV), es el modo aceptado de tratamiento inicial en subgrupos de pacientes con fracaso respiratorio agudo: en pacientes con exacerbación de enfermedad pulmonar obstructiva crónica, pacientes inmunodeprimidos, pacientes con edema pulmonar cardiogénico. Los pacientes oncológicos constituyen una población con características especiales debido a su inmunodepresión multifactorial, lo cual los hace más susceptibles a infecciones severas, presentan diferente grado de desnutrición y de trastornos hematológicos. La insuficiencia respiratoria en este grupo de pacientes es causa creciente de admisión a la Unidad de Cuidados Intensivos (UCI), la mortalidad asociada es 70%, tres veces más que en pacientes no oncológicos. La infección es el principal determinante de la insuficiencia respiratoria. El uso de VMNI ha demostrado disminución en la tasa de morbilidad, mortalidad y estancia hospitalaria en pacientes críticos oncológicos. Esta revisión hace énfasis en los avances de la VMNI en pacientes inmunodeprimidos con neoplasia hematológica.

Noninvasive ventilation with positive pressure (NIPPV) is the accepted mode of initial treatment in subgroups of patients with acute respiratory failure, either in patients with exacerbation of chronic obstructive pulmonary disease: immunocompromised patients, cardiogenic pulmonary edema. Cancer patients are a population with special characteristics due to its multifactorial immunosuppression, which makes them more susceptible to severe infections, have varying degrees of malnutrition and blood disorders. Respiratory failure in this group of patients is a growing cause of admission to the intensive care unit (ICU) and is associated with increased mortality that exceeds 70%, three times more than non-cancer patients. And, as always, the infection is the major determinant of respiratory failure. The use of NIV has been shown in several studies decreased morbidity, mortality and hospital stay in critically ill patients with cancer. A review of the subject, emphasizing the progress of the NIV in immunosuppressed patients with hematologic malignancy.