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Original research article
Forced air warming during sedation in the cardiac catheterisation laboratory: a randomised controlled trial
  1. Aaron Conway1,2,
  2. Suzanna Ersotelos3,
  3. Joanna Sutherland4,5,
  4. Jed Duff6
  1. 1 Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
  2. 2 Cardiac Catheter Theatres, The Wesley Hospital, Brisbane, Queensland, Australia
  3. 3 Cardiac Catheter Laboratory, St Vincent’s Private Hospital, Sydney, Australia
  4. 4 Department of Anaesthesia, Coffs Harbour Health Campus, Coffs Harbour, Australia
  5. 5 Rural Clinical School, University of New South Wales, Coffs Harbour, New South Wales, Australia
  6. 6 School of Nursing and Midwifery, University of Newcastle, Callaghan, New South Wales, Australia
  1. Correspondence to Dr Aaron Conway, The Wesley Hospital & Queensland University of Technology, Institute of Health and Biomedical Innovation, Kelvin Grove, QLD 4059, Australia; aaron.conway{at}


Objective Forced air warming (FAW) during general anaesthesia is a safe and effective intervention used to reduce hypothermia. The objective of this study was to determine if FAW reduces hypothermia when used for procedures performed with sedation in the cardiac catheterisation laboratory.

Methods A parallel-group randomised controlled trial was conducted. Adults receiving sedation in a cardiac catheterisation laboratory at two sites were randomised to receive FAW or usual care, which involved passive warming with heated cotton blankets. Hypothermia, defined as a temperature less than 36°C measured with a sublingual digital thermometer after procedures, was the primary outcome. Other outcomes were postprocedure temperature, shivering, thermal comfort and major complications.

Results A total of 140 participants were randomised. Fewer participants who received FAW were hypothermic (39/70, 56% vs 48/69, 70%, difference 14%; adjusted RR 0.75, 95% CI=0.60 to 0.94), and body temperature was 0.3°C higher (95% CI=0.1 to 0.5, p=0.004). FAW increased thermal comfort (63/70, 90% vs51/69, 74% difference 16%, RR 1.21, 95% CI=1.04 to 1.42). The incidence of shivering was similar (3/69, 4% vs 0/71 0%, difference 4%, 95% CI=−1.1 to 9.8). One patient in the control group required reintervention for bleeding. No other major complications occurred.

Conclusion FAW reduced hypothermia and improved thermal comfort. The difference in temperature between groups was modest and less than that observed in previous studies where use of FAW decreased risk of surgical complications. Therefore, it should not be considered clinically significant.

Trial registration number ACTRN12616000013460.

  • cardiac procedures and therapy
  • health care economics
  • health services

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  • Contributors AC, JD and JS designed the study. AC and SE collected data. AC analysed the data and wrote the first draft of the manuscript. All authors contributed important intellectual content to the drafted manuscript and approved it for publication.

  • Funding Dr AC was awarded an NHMRC Early Career Fellowship to conduct this study and other related research (APP1091657). This study is funded by a St Vincent’s Clinic Foundation Multidisciplinary Patient Focussed Research Grant. Equipment for the study has been awarded by the Covidien Investigator Sponsored Research Program.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Ethics approval Informed consent was obtained from each participant, and the study protocol conforms to the 1975 Declaration of Helsinki as reflected by the university and hospital human research ethics committee approvals (UCH HREC 1505; QUT HREC 1500000643; SVH HREC 15/263).

  • Provenance and peer review Not commissioned; externally peer reviewed.

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