Study protocol This study will be conducted with two patient cohorts: 1) fixed wing patient cohort in pressurized cabin, and 2) rotor wing patient cohort in unpressurized cabin. Each cohort will be randomized to a 'sterile saline' ('experimental') or an 'air' ('control') arm. The paramedics will use a study-specific medical directive approved by the Ornge Medical Advisory Committee. Prior to commencing the study, paramedics will review a self-directed learning module. One investigator will contact each paramedic to confirm completion of the module and answer any questions. Paramedics will be able to enroll patients after the investigator confirms completion of the materials.