J Thorac Cardiovasc Surg 2006;131:252
© 2006 The American Association for Thoracic Surgery
Reply to the Editor
U. Fakler, MD,
J. Hess, MD, PhD
German Heart Center, Department of Pediatric Cardiology and Congenital Heart Disease, Technische Universität München Lazarettstraße 36, D-80636 Munich, Germany
We thank Dr Li and colleagues for their important comments to our article and appreciate their remarks. In particular, their results in patients during the postoperative period concerning determinants and implications of oxygen consumption (VO
2), a patient group that was not included by us, are essential.
1
In addition, their work presents the important conclusion that also other predictive equations published by LaFarge-Miettinen, Lundell and associates
2
, Wessel and colleagues,
3
and Lindahl
4
do not accurately estimate VO
2. Of course we should have cited their article.
1,5
Our study was especially designed to assess the importance of measured VO
2 in the preoperative diagnostic hemodynamic evaluation during cardiac catheterization. Our results emphasize that both the Krovetz-Goldbloom formula,
6
which was used so far in our institution, and the most commonly used formula published by LaFarge and Miettinen
2
are not feasible in all patients to assume VO
2 to calculate cardiac output by using the Fick principle.
In contrast to the studies by Li and associates,
1,5
VO
2 was measured with the standard commercial metabolic monitor Deltatrac II (Datex-Engström, Helsinki, Finland). This system is an open-air system equipped with a fast differential paramagnetic oxygen sensor to measure a differential signal between inspired and expired gases and a gas dilution system to measure flow.
7,8
In contrast to the mass spectrometer method used by Li and associates, in our design no special adaptation in ventilated patients was necessary. After exclusion of any relevant air leak, the Deltatrac II device is easy to handle and allows a feasible and reliable method to measure VO
2.
 |
References
|
|---|
- Li J, Bush A, Schulze-Neick I, Penny DJ, Redington AN, Shekerdemian LS. Measured versus estimated oxygen consumption in ventilated patients with congenital heart disease. the validity of predictive equations. Crit Care Med 2003;31:1235-1240.[Medline]
- LaFarge CG, Miettinen OS. The estimation of oxygen consumption. Cardiovasc Res 1970;4:23-30.[Abstract/Free Full Text]
- Wessel HU, Rorem D, Muster AJ. Continous determination of oxygen uptake in sedated infants and children during cardiac catheterization. Am J Cardiol 1969;24:376-385.[Medline]
- Lindahl SG. Oxygen consumption and carbon dioxide elimination in infants and children during anaesthesia and surgery. Br J Anaesth 1989;62:70-76.[Abstract/Free Full Text]
- Li J, Schulze-Neick I, Lincoln C, Shore D, Scallan M, Bush A, et al. Oxygen consumption after cardiopulmonary bypass surgery in children. determinants and implications. J Thorac Cardiovasc Surg 2000;119:525-533.[Abstract/Free Full Text]
- Krovetz LJ, Goldbloom S. Normal standards for cardiovascular data. I. Examination of the validity of cardiac index. Johns Hopkins Med J 1972;130:174-186.[Medline]
- Tissot S, Delafosse B, Bertrand O, Bouffard Y, Viale JP, Annat G. Clinical validation of the Deltatrac monitoring system in mechanically ventilated patients. Intensive Care Med 1995;21:149-153.[Medline]
- Takala J, Keinänen O, Väisänen P, Kari A. Measurements of gas exchange in intensive care; laboratory and clinical validation of a new device. Crit Care Med 1980;18:638-644.
Top
References