Báo cáo y học: Clinical value of an arterial pressure-based cardiac output measurement device.

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Báo cáo y học: "Clinical value of an arterial pressure-based cardiac output measurement device." Available online http://ccforum.com/content/12/1/403LetterClinical value of an arterial pressure-based cardiac outputmeasurement deviceJoris Lemson and Johannes G van der HoevenDepartment of Intensive Care Medicine, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, The NetherlandsCorresponding author: Joris Lemson, j.lemson@ic.umcn.nlPublished: 25 January 2008 Critical Care 2008, 12:403 (doi:10.1186/cc6219)This article is online at http://ccforum.com/content/12/1/403© 2008 BioMed Central LtdSee related research by McGee et al., http://ccforum.com/content/11/6/R105With interest we read the recent publication by William McGee Furthermore, the authors state that they only consider aand colleagues in which they conclude that arterial pressure- change in cardiac output of 30% or more clinically relevant.based cardiac output (APCO) measurement is comparable to This is in contrast to daily clinical practice in which cardiacintermittent thermodilution cardiac output (ICO) [1]. output changes of 10% to 15% are frequently used for making decisions regarding therapy. Also, they haveHowever, the Bland Altman plot of APCO versus ICO shows calculated the change in cardiac output by dividing the deltaa wide spread of data points with a percentage error of 42%. cardiac output by the mean value before and after the change.These large variations could lead to a completely different In this way they have artificially decreased the relative changeclinical management. Also, we disagree that a percentage in cardiac output. Subsequently, in the plot showing theerror less than 28% is a conservative requirement. By using change in ICO versus the change in APCO, it can bean error-gram, limits of precision of ±20% for both test and observed that when changes in ICO of more than 15% arereference method give predicted limits of agreement of analyzed, in only 35% of the cases did the APCO also change28.3% [2]. These limits should be respected when an 15% or more in the same direction. Moreover, in 45% of thealternative cardiac output measurement technique is evalua- cases the APCO changed in the opposite direction!ted because limits of precision in excess of 20% for a singletechnique are not clinically acceptable. Based on the results of this study, we think that APCO is not accurate in measuring absolute values of cardiac output, nor in tracking changes in cardiac output in a general intensive care population.Authors’ replyWilliam T McGeeFew data support the use of any therapy based on hemo- measurements are likely to reflect greater precision thandynamic variables to improve outcome in intensive care unit usual practice as the investigators would frequently obtain(ICU) patients. In the recently completed FACTT trial, therapy additional (more than four) measurements in an attempt tobased on cardiac output had no impact on patient outcome maximize reliability of the ICO data during the trial, selecting[3]. Other trials targeting cardiac output as a treatment the four measures in best agreement. In two trials involvingvariable have had disappointing results [4]. more homogeneous groups of patients precision was similar [5,6].In our study of ICU patients exhibiting a broad range ofphysiological variability, the limits of precision for ICO are A change in cardiac output of 15% or less should not prompt±36% simply for consecutive measures of ICO. Our ICO a change in management by itself. Basing treatmentAPCO = arterial pressure-based cardiac output; CCO = continuous cardiac output; ICO = intermittent thermodilution cardiac output; ICU = inten-sive care unit. Page 1 of 2 (page number not for citation purposes)Critical Care Vol 12 No 1 Lemson and van der Hoeven ...