Efficacy and safety of high-flow nasal cannula therapy in elderly patients with acute respiratory failure.

INTRODUCTION: To assess the efficacy and safety of high-flow nasal cannula (HFNC) in elderly patients with acute respiratory failure (ARF) not due to COVID-19, refractory to treatment with conventional oxygen therapy and/or intolerant to noninvasive ventilation (NIV) or continuous positive airway pressure (CPAP) and without criteria for admission to intensive care units (ICU). METHODS: Prospective observational study of patients with ARF treated with HFNC who presented clinical and arterial blood gas deterioration after 24 h of medical treatment and oxygenation by conventional systems. The degree of dyspnoea, gas exchange parameters (arterial O2 pressure/inspired O2 fraction ratio (PaO2/FiO2); oxygen saturation measured by oximetry/ inspired fraction of oxygen (Sp02/Fi02), ROX index), degree of patient tolerance and mortality were evaluated. These were measured at discharge from the emergency department (ED), 24 h after treatment with conventional oxygenation and 60, 120 min and 24 h after initiation of HFNC. The results were analyzed for all patients as a whole and for patients with hypercapnia (arterial carbon dioxide tension (PaCO2) < 45 mmHg) separately. RESULTS: 200 patients were included in the study between November 2019 and November 2020, with a mean age of 83 years, predominantly women (61.9%), obese (Body Mass Index (BMI) 31.1), with high comorbidity (Charlson index 4) and mild-moderate degree of dependence (Barthel 60). A number of 128 patients (64%) were hypercapnic. None had respiratory acidosis (pH 7.39). Evaluation at 60 min, 120 min and 24 h showed significant improvement in all patients and in the subgroup of hypercapnic patients with respect to baseline parameters in respiratory rate (RR), dyspnoea, ROX index, PaO2/FiO2, SpO2/FiO2 and patient comfort. No changes in PaCO2 or level of consciousness were observed. HFNC was well tolerated. Ten patients (5%) died due to progression of the disease causing ARF. CONCLUSIONS: HFNC is an effective and safe alternative in elderly patients with ARF not due to COVID-19, refractory to treatment with conventional oxygen therapy and/or intolerant to NIV or CPAP and without criteria for admission to ICU.

[Pre-clinical validation of a turbine-based ventilator for invasive ventilation-The ACUTE-19 ventilator]. / Validación preclínica de un respirador de turbina para la ventilación invasiva: el respirador ACUTE-19.

Background: The severe acute respiratory syndrome-coronavirus 2 pandemic pressure on healthcare systems can exhaust ventilator resources, especially where resources are restricted. Our objective was a rapid preclinical evaluation of a newly developed turbine-based ventilator, named the ACUTE-19, for invasive ventilation. Methods: Validation consisted of (a) testing tidal volume delivery in 11 simulated models, with various resistances and compliances; (b) comparison with a commercial ventilator (VIVO-50) adapting the United Kingdom Medicines and Healthcare products Regulatory Agency-recommendations for rapidly manufactured ventilators; and (c) in vivo testing in a sheep before and after inducing acute respiratory distress syndrome by saline lavage. Results: Differences in tidal volume in the simulated models were marginally different (largest difference 33 ml [95% CI 31 to 36]; P < .001). Plateau pressure was not different (-0.3 cmH2O [95% CI -0.9 to 0.3]; P = .409), and positive end-expiratory pressure was marginally different (0.3 cmH2O [95% CI 0.2 to 0.3]; P < .001) between the ACUTE-19 and the commercial ventilator. Bland-Altman analyses showed good agreement (mean bias -0.29 [limits of agreement 0.82 to -1.42], and mean bias 0.56 [limits of agreement 1.94 to -0.81], at a plateau pressure of 15 and 30 cmH2O, respectively). The ACUTE-19 achieved optimal oxygenation and ventilation before and after acute respiratory distress syndrome induction. Conclusions: The ACUTE-19 performed accurately in simulated and animal models yielding a comparable performance with a VIVO-50 commercial device. The ACUTE-19 can provide the basis for the development of a future affordable commercial ventilator.

Validación preclínica de un respirador de turbina para la ventilación invasiva: el respirador ACUTE-19 Pre-clinical validation of a turbine-based ventilator for invasive ventilation–The ACUTE-19 ventilator

Graphical Antecedentes La pandemia producida por el síndrome respiratorio agudo severo por coronavirus 2 puede agotar los recursos sanitarios, especialmente de respiradores, en situaciones de escasez de recursos sanitarios. Nuestro objetivo fue realizar una evaluación preclínica rápida de un prototipo de respirador de turbina para la ventilación invasiva denominado ACUTE-19. Métodos La validación consistió en: a) evaluación de la administración de un volumen corriente en 11 modelos pulmonares simulados, con diversas resistencias y compliancias;b) comparación con un ventilador comercial (VIVO-50) adaptando las recomendaciones de la Agencia Reguladora de Medicamentos y Productos Sanitarios del Reino Unido para ventiladores de fabricación rápida, y c) realización de pruebas in vivo en una oveja antes y después de inducir el síndrome de distrés respiratorio agudo mediante lavado salino. Resultados Las diferencias de volumen corriente en los modelos simulados fueron mínimamente diferentes (la mayor diferencia fue de 33 ml [IC 95%: 31 a 36];p < 0,001). La presión de meseta no fue diferente (−0,3 cmH2O [IC 95%: −0,9 a 0,3];p = 0,409), y la presión positiva al final de la espiración fue levemente diferente (0,3 cmH2O [IC 95%: 0,2 a 0,3];p < 0,001) comparando el ACUTE-19 y el ventilador comercial. El análisis de Bland-Altman mostró una buena concordancia (sesgo medio −0,29 [límites de concordancia 0,82 a −1,42], y sesgo medio 0,56 [límites de concordancia 1,94 a −0,81], a una presión de meseta de 15 y 30 cmH2O, respectivamente). El ACUTE-19 consiguió una oxigenación y ventilación óptimas antes y después de la inducción del síndrome de distrés respiratorio agudo en el modelo animal. Conclusiones El ACUTE-19 se comportó con precisión en los modelos simulados y animales, con un rendimiento comparable al del dispositivo comercial VIVO-50. El ACUTE-19 puede servir de base para el desarrollo de un futuro ventilador comercial asequible.

Pre-clinical validation of a turbine-based ventilator for invasive ventilation-The ACUTE-19 ventilator.

BACKGROUND: The Severe Acute Respiratory Syndrome (SARS)-Coronavirus 2 (CoV-2) pandemic pressure on healthcare systems can exhaust ventilator resources, especially where resources are restricted. Our objective was a rapid preclinical evaluation of a newly developed turbine-based ventilator, named the ACUTE-19, for invasive ventilation. METHODS: Validation consisted of (a) testing tidal volume (V_T) delivery in 11 simulated models, with various resistances and compliances; (b) comparison with a commercial ventilator (VIVO-50) adapting the United Kingdom Medicines and Healthcare products Regulatory Agency-recommendations for rapidly manufactured ventilators; and (c) in vivo testing in a sheep before and after inducing acute respiratory distress syndrome (ARDS) by saline lavage. RESULTS: Differences in V_T in the simulated models were marginally different (largest difference 33ml [95%-confidence interval (CI) 31-36]; P<.001ml). Plateau pressure (P_plat) was not different (-0.3cmH₂O [95%-CI -0.9 to 0.3]; P=.409), and positive end-expiratory pressure (PEEP) was marginally different (0.3 cmH₂O [95%-CI 0.2 to 0.3]; P<.001) between the ACUTE-19 and the commercial ventilator. Bland-Altman analyses showed good agreement (mean bias, -0.29, [limits of agreement, 0.82 to -1.42], and mean bias 0.56 [limits of agreement, 1.94 to -0.81], at a P_plat of 15 and 30cmH₂O, respectively). The ACUTE-19 achieved optimal oxygenation and ventilation before and after ARDS induction. CONCLUSIONS: The ACUTE-19 performed accurately in simulated and animal models yielding a comparable performance with a VIVO-50 commercial device. The acute 19 can provide the basis for the development of a future affordable commercial ventilator.