Measured versus predicted oxygen consumption in children with congenital heart disease

Abstract

Objective-To compare measured and predicted oxygen consumption (Ṽo 2 ) in children with congenital heart disease. Design-Retrospective study. Results-Lindahl's equation produced the highest precision (±42%) of the regression based estimates. The corresponding average bias of the predicted Ṽo 2 was 3% (range −66% to 43%). When Ṽo 2 was predicted according to regression equations by Wessel and Lundell, the bias and precision were 0% and ±44%, and −16% and ±51%, respectively. The neural network predicted Ṽo 2 from variables included in the regression equations with a bias of 6% and precision ±29%; addition of further variables failed to improve this estimate. Conclusions-Both regression based and artificial intelligence based techniques were inaccurate for predicting preoperative Ṽo 2 in patients with congenital heart disease. Measurement of Ṽo 2 is necessary in the preoperative evaluation of these patients. (Heart 1998;80:601-605) Setting

Age and Method-dependent Variability of Predicted Oxygen Consumption in Congenital Heart Disease

“…In studies aimed at analyzing the discrepancies, different methods of prediction have been tested against measured oxygen consumption, and compared in terms of precision. 4,5 In this study, we did not plan to further evaluate the precision of methods for prediction of oxygen consumption, but rather, to comparatively analyze predictions in specific age groups as to determine, for example, which methods are expected to provide the highest and lowest estimates in each group. 5 Although none of the predictions has proved sufficiently accurate to be considered when precise results are needed, the highest precision has been obtained with the formula of Lindahl.…”

“…[3][4][5] On the other hand, it has been acknowledged that although direct measurement of oxygen consumption is preferable, it is not easily implemented. 1,2 There has been much debate about the use of measured vs. assumed (predicted) values.…”

Accurate Measurement of Systemic Oxygen Consumption in Ventilated Children with Congenital Heart Disease

“…Despite attempts to improve the accuracy of estimated VO 2 values, large discrepancies are still observed between measured and estimated values (Laitinen and Rasanen 1998;Shanahan, Wilson et al 2003;Wolf, Pollman et al 1998). Such discrepancies present challenges in the clinical application of predictive equations e.g., in the catheterization laboratory setting, because subsequent hemodynamic calculations will be impaired.…”

“…Importantly, these parameters can be derived in a variety of simple or complex circulations in congenital heart defects before and after surgical repair or palliation, including 1) biventricular circulation with or without left to right or right to left shunt (Li, Hoschtitzky et al 2004;Li, Schulze-Neick et al 2000; Schulze-Neick, Li et al 2001; Schulze-Neick, Li et al 2002), 2) functionally single ventricular circulation such as hypoplastic left heart syndrome before and after the Norwood procedure , and 3) one-and-a-half ventricular circulation such as after the bidirectional cavopulmonary shunt operation (Hoskote, Li et al 2004;Li, Hoskote et al 2005). If VO 2 needs to be measured, then accuracy of the measurement cannot be overemphasized (Kendrick, West et al 1988;Laitinen and Rasanen 1998;Shanahan, Wilson et al 2003). Any error in VO 2 measurement will translate directly into an equivalent magnitude of underestimation or over-estimation of hemodynamics and oxygen transport parameters, which may misdirect surgical and clinical treatment strategies.…”

Cardiac output determination using a widely available direct continuous oxygen consumption measuring device: a practical way to get back to the gold standard

“…(5-8) Reliability and use of predictive equations for CO measurement have been questioned in the CCL setting because of large discrepancies between measured and estimated values, (9-11) which of course have an influence on subsequent hemodynamic and valve area calculations. (12, 13)…”