The Science Journal of the American Association for Respiratory Care

2011 OPEN FORUM Abstracts


Azadeh Bojmehrani1, Carmelle Bouchard1, Pierre- Alexandre Bouchard1, Ervan L'Her2, Francois Lellouche1; 1Institut Universitaire de Cardiologie et de Pneumologie de Quebec, Quebec, QC, Canada; 2Medical ICU, University hospital of Brest, Brest, France

Introduction: Protective ventilation implementation requires the predicted body weight (PBW) calculation, based on gender and patient's height. Consequently, height inaccuracy may be a limiting factor to adequately reduce the tidal volumes. The main objective of this study was to evaluate a method for measuring the patients while on mechanical ventilation. Methods: Patients were included in the study before cardiac surgery and after informed consent. Reference heights of patients were obtained with a height gauge while patients were standing up (gold standard). Measures were also taken according to the Chumlea method. After the surgery, at ICU arrival, patient's heights were visually estimated by a nurse, a respiratory therapist and then measured by a nurse with a measuring tape. In addition, the patient's height was measured with an optical method (iphone camera) by an algorithm (FreeSize) developed for this study based on analysis of a leg'>s picture. Results: We present here the results for 30 patients (23 men and 7 women). Mean age was 62.3 +/- 10 years; actual weight was 66.7 +/- 5.0 kg. Mean height measured with gauge before the surgery was 171 +/- 8 cm (reference). Mean height measured with camera was 171 +/- 8 cm. Mean height measured with a tape was 170 +/- 15 cm. The median difference between the reference and height found with Freesize was 0.27 cm with a maximum error of 3 cm. The median difference between reference and estimated height was 3.41 cm with a maximum error of 20 cm. The median difference between reference and the tape-measured height was 3 cm with a maximum error of 13 cm. The median difference between the PBW based on reference height and Freesize was 0.05 kg with a maximum error of 2.6 kg. The median difference between the PBW based on actual height and the estimated height was 3.3 kg with a maximum error of 17 kg. Conclusion: This study demonstrates that our new method to provides acceptable results, at least equivalent to the measure with a tape when patients are lying in bed under mechanical ventilation and better than the visual estimation. This technique could be useful to optimize the implementation of protective mechanical ventilation.
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Difference between the three measuring methods.