Abstract— In response to Covid-19 crisis, 310 Masi ventilators were produced and validated in Lima, Peru, according to applicable standards. Four of them, were transported to Puno, in order to strengthen ICU Services there, but this set a major challenge to Masi team as effects of altitude on ventilators were unknown. Once there, ventilators were acclimated and calibrated. Volume tidal, I:E ratio, respiratory frequency and PEEP were tested, all of them presenting errors under 15%, except for tidal volume, for which a 25% negative correction was applied. After the installation of a new version of Masi software, parameters were tested again, all of them presenting results with errors below 15%, which allowed the Masi team to take them to ICU services for use. Clinical Relevance— Masi Peruvian Ventilators are able to perform according to their specifications at extremely high altitude, after the adequate calibration. These devices are an alternative to treat COVID-19 patients in the middle of the crisis. I. INTRODUCTION In response to COVID-19 crisis, five innovation-centered institutions in Peru –DIACSA, Energy Automation Technologies, Zolid Design, Brein & Pontificia Universidad Catolica del Peru, PUCP) gathered a team to develop a ventilator with sufficient functionality to safely treat patients with ARDS, while reducing the production time, logistical complications and cost to make ventilators available to assist and sustain the already saturated Intensive Care Units (ICU) system or any emergency point of care. Masi ventilator is composed of mechanical, electronic and pneumatic parts. Its design makes use of a manual resuscitator as core driver to insufflate air into the patient airways via a mask and includes basic alarms indicating high or low pressure or volume to notify the healthcare provider when desired parameters are not being met or if there is a significant problem with the system. Additionally, control and monitoring of oxygen concentration is provided and this device can be used as invasive and non-invasive ventilator types, both mandatory and spontaneous [1]. Masi technical specifications are shown in table I. Three hundred and ten Masi Ventilators were produced with the aim that these would be donated to different hospitals in Peru. For each of them, the team performed the validation *Research supported by Project MASI and its donors. S. P-B., is with Laboratorio de Metrología y Validación de Dispositivos Médicos and Grupo de Dispositivos Médicos from the Departamento de Ingeniería Pontificia Universidad Catolica del Peru, Lima, Peru (phone: +51 922303342, e-mail: sm.perez@ pucp.edu.pe). D. G-A., is with Laboratorio de Metrología y Validación de Dispositivos Médicos from the Departamento de Ingeniería Pontificia Universidad Catolica del Peru, Lima, Peru (e-mail: dgomeza@pucp.edu.pe). M. C., is with Laboratorio de Metrología y Validación de Dispositivos Médicos from the Departamento de Ingeniería Pontificia Universidad tests required for RMVS001-Specification [2, 3], the standard applicable, using calibrated flow analyzers. These tests were performed in Lima, at the sea level, where the majority of ventilators are used in critical care environments, being this city the capital and largest city of the country. However, due to the extension of the emergency, it was necessary to place 4 of the ventilators in the city of Puno, at an altitude of 3800 meters above the sea level, in order to strengthen the ICU services at the Hospital Regional Manuel Núñez Butrón in Puno. TABLE I. MASI VENTILATOR TECHNICAL SPECIFICATIONS Ventilation mode Parameter Default Value Interval Min. Value Max. Value General Trigger 5 5 10 FiO2 21 21 100* PEEP 0 0 20 VC-CMV VT 400 200 800 RPM 15 4 35 Ti 1.0 0.7 7.5 PC-CMV PC 15 5 35 RPM 15 4 35 Ti 1.0 0.7 7.5 PC-CSV PS 10 5 30 Cycle 20 5 40 Tap 15 2 20 Catolica del Peru, Lima, Peru (e-mail: mcordovat@pucp.edu.pe and mbornas@pucp.edu.pe). C. R. and J. C., is with Diacsa and the Departamento de Ingeniería Pontificia Universidad Catolica del Peru, Lima, Peru (e-mail: crojas@diacsa.com and jchang@pucp.edu.pe). B. C., is with the Laboratorio de Imágenes Médicas and Grupo de Dispositivos Médicos from the Departamento de Ingeniería Pontificia Universidad Catolica del Peru, Lima, Perú, (e-mail: castaneda.b@pucp.edu.pe). Performance of the Masi Peruvian ventilator at high altitude Sandra Pérez-Buitrago, Daniela Gómez-Alzate, Mauricio Córdova, Christiam Rojas, Javier Chang, Benjamin Castaneda 2021 43rd Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC) Oct 31 - Nov 4, 2021. Virtual Conference © IEEE 2021. This article is free to access and download, along with rights for full text and data mining, re-use and analysis. 5031 2021 43rd Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC) | 978-1-7281-1179-7/21/$31.00 ©2021 IEEE | DOI: 10.1109/EMBC46164.2021.9630947