J Thorac Cardiovasc Surg 2006;131:929-930
© 2006 The American Association for Thoracic Surgery
Evaluation of a modified ThermoWrapTM for the AllonTM warming system in patients undergoing elective off-pump coronary artery bypass grafting
C.K. Hofer, MD, DEAA
a
,
Michael T. Ganter, MD, DEAA
b
,
Andreas Zollinger, MD
c
a Institute of Anesthesiology and Intensive Care Medicine, Triemli City Hospital, Birmensdorferstr. 497, 8063 Zurich, Switzerland
b Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, Calif
c Institute of Anesthesiology and Intensive Care Medicine, Triemli City Hospital, Zurich, Switzerland
To the Editor:
We have previously shown in this journal
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that the AllonTM patient-warming system (AllonTM 2001 system; MTRE Advanced Technologies Ltd, Or-Akiva Industrial Park, Israel) is efficient in maintaining normothermia during off-pump coronary artery bypass grafting (OPCABG), resulting in reduced perioperative blood loss and transfusion requirements. However, the ThermoWrapTM used with this system is expensive, complications (ie, burns) have been described,
2
and handling can be time consuming. Meanwhile, we evaluated the new version of a ThermoWrapTM for the AllonTM system in terms of handling and efficacy. In contrast to the old version of the ThermoWrapTM, the design of the new wrap has been modified to improve patient care and to reduce potential skin damage, as well as costs. With institutional approval and informed consent, 40 consecutive patients (mean age ± standard deviation [SD], 68 ± 10 years; mean body mass index ± SD, 28 ± 5 kg · m–2; mean Euroscore ± SD, 6 ± 3) undergoing elective OPCABG were randomly assigned to either the original (group A, n = 20) or the modified (group B, n = 20) ThermoWrapTM. According to our previous temperature measurement study,
1
active warming was started after induction of anesthesia, with the AllonTM system set to 36.9°C body core temperature (BCT). BCT was recorded every 30 minutes during surgical intervention, and maximal intraoperative BCT decrease, as well as increase, was calculated. Skin alterations (reddening) were assessed by using a visual analog scale (score, 1-10) at the end of the procedure. During the clinical evaluation, 15 involved staff members completed a questionnaire on handling of the AllonTM system. The answers were recorded by using a Likert scale (score, 1-4). The Student t test was used for statistical analyses. Durations of OPCABG procedures were comparable (group A, 257 ± 59 minutes; group B, 269 ± 53 minutes; P = .89). There was no significant difference of BCT at the beginning and end of the intervention (Figure 1). Intraoperative BCT changes were significantly different for group A compared with group B (BCT decrease/increase: group A, –0.7°C ± 0.4°C/+1.2°C ± 0.3°C; group B, –0.4°C ± 0.3°C/+1.0°C ± 0.3°C; P < .05). Skin alterations were comparable for both groups (visual analog scale: group A, 6 ± 1; group B, 6 ± 1; P = .78). According to 80% of the interviewed staff members, positioning of the modified wrap B was superior and less time consuming compared with wrap A. On the basis of these results, patient management can be further improved by using the AllonTM system with the new modified ThermoWrapTM.
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Figure 1. Intraoperative course of body core temperature using the old and modified ThermoWraps for the AllonTM 2001 system. BCTBaseline
: Body core temperature after induction of anesthesia before surgical intervention; BCTLow
: lowest intraoperative body core temperature; BCTEnd
: body core temperature at the end of surgical intervention.
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This study was performed without any financial support from manufacturers or the pharmaceutical industries. The AllonTM 2001 system is used on a regular basis for all patients undergoing OPCABG at the Triemli City Hospital. The modified ThermoWraps were provided free of charge by MTRE Advanced Technologies Ltd, Israel. None of the authors is related to or has financial interests in the manufacturers of the products studied. Also, there are no consultancy agreements between any authors and the manufacturer. Moreover, no specific institutional funding was necessary because all authors are regularly employed at the institutions mentioned above.
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References
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- Hofer CK, Worn M, Tavakoli R, Sander L, Maloigne M, Klaghofer R, et al. Influence of body core temperature on blood loss and transfusion requirements during off-pump coronary artery bypass grafting. a comparison of 3 warming systems. J Thorac Cardiovasc Surg. 2005;129:838-843.[Abstract/Free Full Text]
- Gali B, Findlay JY, Plevak DJ. Skin injury with the use of a water warming device. Anesthesiology. 2003;98:1509-1510.[Medline]
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