Hospital Mortality and Effect of Adjusting PaO2/FiO2 According to Altitude Above the Sea Level in Acclimatized Patients Undergoing Invasive Mechanical Ventilation. A Multicenter Study Manuel Jibaja; Guillermo Ortiz-Ruiz; Fernanda García; Manuel Garay-Fernández; Felipe de Jesús Montelongo; Jorge Martinez; José Antonio Viruez; Orville Baez-Pravia; Santiago Salazar; Francisco Villacorta-Cordova; Freddy Morales; Amilcar Tinoco-Solórzano; Carlos Ibañez Guzmán; Bruno Valle Pinheiro; Felix Zubia-Olaskoaga; Carmelo Dueñas; Antonio Lara Garcia; Pablo Cardinal-Fernández;