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Background: The COVID-19 pandemic in Latin America generated the need to develop low-cost, fast-manufacturing mechanical ventilators. The Universidad de La Sabana and the Fundacion Neumologica Colombiana designed and manufactured the Unisabana-HERONS (USH) ventilator. Here, we present the preclinical and clinical study results to evaluate its effectiveness and safety characteristics in an animal model (Yorkshire Sow) and five patients with acute respiratory failure receiving mechanical ventilatory support for 24 h. Methods: The effectiveness and safety outcomes included maintaining arterial blood gases and pulse oximetry saturation (SpO2), respiratory pressures and volumes (during continuous monitoring) in the range of ARDS and lung-protective strategy goals, and the occurrence of barotrauma. A significance level of 0.05 was used for statistical tests. This clinical trial was registered on Clinicaltrials.gov (NCT04497623) and approved by the ethics committee. Results: Among patients treated with the Unisabana-HERONS, the most frequent causes of acute respiratory failure were pneumonia in 3/5 (60 %) and ARDS in 2/5 (40 %). During the treatment, the ventilatory parameters related to lung protection protocols were kept within the safety range, and vital signs and blood gas were stable. The percentage of time that the respiratory pressures or volumes were out of safety range were plateau pressure >30 cm H2O: 0.00 %; driving pressure >15 cm H2O: 0.06 %; mechanical power >15 J/min: 0.00 %; and Tidal volume >8 mL/kg: 0.00 %. There were no adverse events related to the ventilator. The usability questionnaire retrieved a median score for all items between 9 and 10 (best score: 10), indicating great ease of use. Conclusion: The Unisabana-HERONS ventilator effectively provided adequate gas exchange and maintained the ventilatory parameters in the range of lung protection strategies in humans and an animal model. Furthermore, it is straightforward to use and is a low-cost medical device.
RESUMO
BACKGROUND: Utilizing clinical tests, such as objective cough measurement, can assist in predicting the success of the weaning process in critically ill patients. METHODS: A multicenter observational analytical study was conducted within a prospective cohort of patients recruited to participate in COBRE-US. We assessed the capability of objective cough measurement to predict the success of the spontaneous breathing trial (SBT) and extubation. Intra- and inter-observer reproducibility of the cough test and was evaluated using the intraclass correlation coefficient (ICC) and Cohen's weighted kappa. We used receiver operating characteristic curves (ROC-curve) to evaluate the predictive ability of objective cough measurement. RESULTS: We recruited 367 subjects who were receiving invasive mechanical ventilation. A total of 451 objective cough measurements and 456 SBTs were conducted. A significant association was found between objective cough measurement and successful SBT (OR: 1.68; 95% CI 1.48-1.90; p = 0.001). The predictive capability of the objective cough test for SBT success had a ROC-curve of 0.58 (95% CI: 0.56-0.61). Objective cough measurement to predict successful extubation had a ROC-curve of 0.61 (95% CI: 0.56-0.66). The intraobserver reproducibility exhibited an ICC of 0.94 (95% CI: 0.89-0.96; p < 0.001), while the interobserver reproducibility demonstrated an ICC of 0.72 (95% CI: 0.51-0.85; p < 0.001). The intraobserver agreement, assessed using Cohen's weighted kappa was 0.94 (95% CI: 0.93-0.99; p < 0.001), whereas the interobserver agreement was 0.84 (95% CI: 0.67 - 0.10; p < 0.001). CONCLUSIONS: The objective measurement of cough using the method employed in our study demonstrates nearly perfect intra-observer reproducibility and agreement. However, its ability to predict success or failure in the weaning process is limited.