An Open label, Randomised Controlled trial on the effectiveness of the Orve+ Wrap® versus Forced Air Warming in restoring normothermia in the Post Anaesthetic Care Unit

AIMS AND OBJECTIVES: This study aims to determine the clinical effectiveness and safety of the Orve+Wrap® thermal blanket. BACKGROUND: Inadvertent peri-operative hypothermia is a common problem in Post Anaesthetic Care Units and can have significant effects on patients' post-operative morbidity. Despite its commercial availability there is no clinical evidence on the effectiveness of Orve+Wrap®. DESIGN: A single centre prospective, open label, non-inferiority randomized controlled trial. METHODS: Post-operative hypothermic (35.0°C - 35.9°C) patients who had undergone elective surgery were randomised to receive either Orve+Wrap® or Forced Air Warming for the during their PACU stay. Patient temperatures we recorded every 10 minutes using Zero Heat Flux Thermometry. This study is reported using CONSORT Extension checklist for non-inferiority and equivalence trials. RESULTS: Between December 2016 and October 2018, 129 patients were randomised to receive either Orve+wrap® blanket, (n=65, 50.3%) or Forced Air Warming, (n= 64, 49.7%). The mean 60-minute post-operative temperature of patients receiving Orve+wrap® blanket was 36.2°C and 36.3°C for the patients receiving Forced Air Warming. The predefined non-inferiority margin of a mean difference in temperature of 0.3°C, was not reached between the groups at 60 minutes. Additionally, there were no statistical differences between adverse event rates across these groups. CONCLUSIONS: In the context of this study warming patients with the Orve+wrap® was non-inferior to Forced Air Warming. There were comparable rates of associated post-operative consequences of warming (shivering, hypotension, arrhythmias or surgical site infections), between the groups. RELEVANCE TO CLINICAL PRACTICE: The Orve+wrap® potentially provides an alternative warming method to Forced Air Warming for patients requiring short term post-operative warming. However, there are still a number of unknowns regarding the Orve+wrap® performance and further exploration is required.