Safety during interhospital helicopter transfer of ventilated COVID-19 patients. No clinical relevant changes in vital signs including non-invasive cardiac output oleh Cornelis Slagt, Eduard Johannes Spoelder, Marijn Cornelia Theresia Tacken, Maartje Frijlink, Sjoerd Servaas, Guus Leijte, Lucas Theodorus van Eijk, Geert Jan van Geffen