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Accuracy of a cardiac output monitor: Is it a relevant issue without an adequate therapeutic algorithm?
Anaesth Crit Care Pain Med 35 (2016) 243–244
Editorial
Accuracy of a cardiac output monitor: Is it a relevant issue without an adequate therapeutic algorithm?
In this issue of Anaesthesia Critical Care & Pain Medicine, two articles investigated cardiac output monitoring: a validation study and an outcome study. Fisher et al. [1] evaluated the trending ability of calibrated pulse contour cardiac index monitoring during haemodynamic changes (passive leg raising and fluid loading). Picard et al. [2] investigated the feasibility and impact of perioperative hemodynamic optimization with oesophageal Doppler in patients in the supine position. A few years ago, the only way to monitor cardiac output was through pulmonary arterial catheter (PAC). Major technological advances have allowed the development of less invasive monitors. Oesophageal Doppler was one of the first minimally invasive tools available, followed by pulse contour technologies, bioimpedence, bioreactance. . . Monitors are less invasive and increasingly easy to use. But are they accurate? Many clinical studies have investigated the accuracy of these devices, using specific statistical tools, in order to conclude whether two cardiac output monitors are interchangeable or not [3–5]. However, Le Manach and Collins reported that these studies require more rigorous methodologies to permit relevant conclusion for the physician [6]. Moreover, is it important to know the exact value of the patient’s cardiac output? Probably yes in specific situations: cardiac surgery, weaning from cardiac assistance. Most of the time, and particularly during perioperative hemodynamic optimization, we need to know the direction and the magnitude of cardiac output changes after a therapeutic intervention (most frequently after volume expansion). Here again, specific statistical tools have been developed to assess the issue (angle, radial limits of agreement, with and without exclusion zone) [7,8]. While this approach to assess cardiac output changes is more relevant, it is probably incomplete. Feldman reported that analytical methods for comparing cardiac output measurement techniques need to
move beyond this approach to provide insight into the role of the technology in clinical decision making. The impacts of those decisions on patient outcome are the ultimate question. The daily concern of physicians is to improve patient outcome, thus cardiac output monitors should be evaluated on this basis [9] (Fig. 1). It is amazing to observe that PAC outcome studies are disappointing even though it is considered as the most accurate technique [10]. On the other hand, it has been demonstrated that perioperative hemodynamic optimization using oesophageal Doppler (which is clearly less accurate than PAC) is a benefit for patients [11]. Similar observations have been made with the moderately accurate pulse contour analysis technology as well as the increasing number of positive outcome studies using these devices [12]. For these reasons, at least two comments need to be emphasized. First, after a therapeutic intervention, variations in cardiac output are more appropriate in the clinical setting than absolute values (except for extreme values and specific situations). Second, the associated therapeutic protocol plays a more significant role in patient outcome than the cardiac monitor [11]. The bottom line is, in a large number of PAC studies, there are no therapeutic protocols associated with cardiac output monitoring. In this issue, the Doppler study was done using a precise algorithm. Interestingly, the same type of algorithm was used in the pulse contour study with positive results. This underlines the fact that it is the associated therapeutic protocol and not cardiac output monitoring which is a benefit for patients [13]. In conclusion, clinical studies evaluating the accuracy of a cardiac output monitor are necessary but not sufficient. They must be accompanied by outcome studies. Hemodynamic tools may improve outcome only if is they are associated with a therapeutic protocol.
Fig. 1. Evaluation of a cardiac output monitor.
http://dx.doi.org/10.1016/j.accpm.2016.06.003 2352-5568/ß 2016 Socie´te´ franc¸aise d’anesthe´sie et de re´animation (Sfar). Published by Elsevier Masson SAS. All rights reserved.
244
Editorial / Anaesth Crit Care Pain Med 35 (2016) 243–244
Disclosure of interest MB: received honoraria for lecturers from Edwards Lifesciences and Maquet Critical Care. RL and JYL declare that they have no competing interest. References [1] Fisher MO, Rebet O, Guinot PG, Leme´tayer C, Saplacan V, Ge´rard JL, et al. Assessment of changes in cardiac index with calibrated pulse contour analysis in cardiac surgery: a prospective observational study. Anaesth Crit Care Pain Med 2016;35. http://dx.doi.org/10.1016/j.accpm.2015.12.010. [2] Picard J, Bedague D, Bouzat P, Ollinet C, Albaladejo P, Bosson JL, et al. Oesophageal Doppler to optimize intraoperative haemodynamics during prone position. A randomized controlled trial. Anaesth Crit Care Pain Med 2016;35. http://dx.doi.org/10.1016/j.accpm.2015.12.011. [3] Schlo¨glhofer T, Gilly H, Schima H. Semi-invasive measurement of cardiac output based on pulse contour: a review and analysis. Can J Anaesth J Can Anesth 2014;61:452–79. [4] Mayer J, Boldt J, Poland R, Peterson A, Manecke GR. Continuous arterial pressure waveform-based cardiac output using the FloTrac/Vigileo: a review and meta-analysis. J Cardiothorac Vasc Anesth 2009;23:401–6. [5] Critchley LA, Critchley JA. A meta-analysis of studies using bias and precision statistics to compare cardiac output measurement techniques. J Clin Monit Comput 1999;15:85–91. [6] Le Manach Y, Collins GS. Disagreement between cardiac output measurement devices: which device is the gold standard? Br J Anaesth 2016;116:451–3. [7] Critchley LA, Lee A, Ho AM-H. A critical review of the ability of continuous cardiac output monitors to measure trends in cardiac output. Anesth Analg 2010;111:1180–92. [8] Critchley LA, Yang XX, Lee A. Assessment of trending ability of cardiac output monitors by polar plot methodology. J Cardiothorac Vasc Anesth 2011;25:536–46. [9] Feldman JM. Is it a bird? Is it a plane? The role of patient monitors in medical decision making. Anesth Analg 2009;108:707–10.
[10] Harvey S, Harrison DA, Singer M, Ashcroft J, Jones CM, Elbourne D, et al. Assessment of the clinical effectiveness of pulmonary artery catheters in management of patients in intensive care (PAC-Man): a randomised controlled trial. Lancet 2005;366:472–7. [11] Phan TD, Ismail H, Heriot AG, Ho KM. Improving perioperative outcomes: fluid optimization with the esophageal Doppler monitor, a meta-analysis and review. J Am Coll Surg 2008;207:935–41. [12] Funk DJ, Moretti EW, Gan TJ. Minimally invasive cardiac output monitoring in the perioperative setting. Anesth Analg 2009;108:887–97. [13] Pinsky MR, Vincent JL. Let us use the pulmonary artery catheter correctly and only when we need it. Crit Care Med 2005;33:1119–22.
Matthieu Biais (MD, Ph.D). a,b,*, Romain Lanchon (MD) a Jean-Yves Lefrant (MD, Ph.D). c,d a Service d’Anesthe´sie et de Re´animation 3, CHU de Bordeaux, Hoˆpital Pellegrin, place Ame´lie-Raba-Le´on, 33076 Bordeaux cedex, France b Universite´ de Bordeaux, Bordeaux, France c Service des Re´animations, Division Anesthe´sie, Re´animation, Urgences, Douleur, CHU de Nıˆmes, place du Professeur-Robert-Debre´, 30029 Nıˆmes cedex 9, France d Universite´ de Nıˆmes, Nıˆmes, France *Corresponding author at: Service d’Anesthe´sie et de Re´animation 3, CHU de Bordeaux, Hoˆpital Pellegrin, place Ame´lie-Raba-Le´on, 33076 Bordeaux cedex, France E-mail addresses: [email protected] (M. Biais), [email protected] (R. Lanchon), [email protected] (J.-Y. Lefrant)
Editorial
Accuracy of a cardiac output monitor: Is it a relevant issue without an adequate therapeutic algorithm?
In this issue of Anaesthesia Critical Care & Pain Medicine, two articles investigated cardiac output monitoring: a validation study and an outcome study. Fisher et al. [1] evaluated the trending ability of calibrated pulse contour cardiac index monitoring during haemodynamic changes (passive leg raising and fluid loading). Picard et al. [2] investigated the feasibility and impact of perioperative hemodynamic optimization with oesophageal Doppler in patients in the supine position. A few years ago, the only way to monitor cardiac output was through pulmonary arterial catheter (PAC). Major technological advances have allowed the development of less invasive monitors. Oesophageal Doppler was one of the first minimally invasive tools available, followed by pulse contour technologies, bioimpedence, bioreactance. . . Monitors are less invasive and increasingly easy to use. But are they accurate? Many clinical studies have investigated the accuracy of these devices, using specific statistical tools, in order to conclude whether two cardiac output monitors are interchangeable or not [3–5]. However, Le Manach and Collins reported that these studies require more rigorous methodologies to permit relevant conclusion for the physician [6]. Moreover, is it important to know the exact value of the patient’s cardiac output? Probably yes in specific situations: cardiac surgery, weaning from cardiac assistance. Most of the time, and particularly during perioperative hemodynamic optimization, we need to know the direction and the magnitude of cardiac output changes after a therapeutic intervention (most frequently after volume expansion). Here again, specific statistical tools have been developed to assess the issue (angle, radial limits of agreement, with and without exclusion zone) [7,8]. While this approach to assess cardiac output changes is more relevant, it is probably incomplete. Feldman reported that analytical methods for comparing cardiac output measurement techniques need to
move beyond this approach to provide insight into the role of the technology in clinical decision making. The impacts of those decisions on patient outcome are the ultimate question. The daily concern of physicians is to improve patient outcome, thus cardiac output monitors should be evaluated on this basis [9] (Fig. 1). It is amazing to observe that PAC outcome studies are disappointing even though it is considered as the most accurate technique [10]. On the other hand, it has been demonstrated that perioperative hemodynamic optimization using oesophageal Doppler (which is clearly less accurate than PAC) is a benefit for patients [11]. Similar observations have been made with the moderately accurate pulse contour analysis technology as well as the increasing number of positive outcome studies using these devices [12]. For these reasons, at least two comments need to be emphasized. First, after a therapeutic intervention, variations in cardiac output are more appropriate in the clinical setting than absolute values (except for extreme values and specific situations). Second, the associated therapeutic protocol plays a more significant role in patient outcome than the cardiac monitor [11]. The bottom line is, in a large number of PAC studies, there are no therapeutic protocols associated with cardiac output monitoring. In this issue, the Doppler study was done using a precise algorithm. Interestingly, the same type of algorithm was used in the pulse contour study with positive results. This underlines the fact that it is the associated therapeutic protocol and not cardiac output monitoring which is a benefit for patients [13]. In conclusion, clinical studies evaluating the accuracy of a cardiac output monitor are necessary but not sufficient. They must be accompanied by outcome studies. Hemodynamic tools may improve outcome only if is they are associated with a therapeutic protocol.
Fig. 1. Evaluation of a cardiac output monitor.
http://dx.doi.org/10.1016/j.accpm.2016.06.003 2352-5568/ß 2016 Socie´te´ franc¸aise d’anesthe´sie et de re´animation (Sfar). Published by Elsevier Masson SAS. All rights reserved.
244
Editorial / Anaesth Crit Care Pain Med 35 (2016) 243–244
Disclosure of interest MB: received honoraria for lecturers from Edwards Lifesciences and Maquet Critical Care. RL and JYL declare that they have no competing interest. References [1] Fisher MO, Rebet O, Guinot PG, Leme´tayer C, Saplacan V, Ge´rard JL, et al. Assessment of changes in cardiac index with calibrated pulse contour analysis in cardiac surgery: a prospective observational study. Anaesth Crit Care Pain Med 2016;35. http://dx.doi.org/10.1016/j.accpm.2015.12.010. [2] Picard J, Bedague D, Bouzat P, Ollinet C, Albaladejo P, Bosson JL, et al. Oesophageal Doppler to optimize intraoperative haemodynamics during prone position. A randomized controlled trial. Anaesth Crit Care Pain Med 2016;35. http://dx.doi.org/10.1016/j.accpm.2015.12.011. [3] Schlo¨glhofer T, Gilly H, Schima H. Semi-invasive measurement of cardiac output based on pulse contour: a review and analysis. Can J Anaesth J Can Anesth 2014;61:452–79. [4] Mayer J, Boldt J, Poland R, Peterson A, Manecke GR. Continuous arterial pressure waveform-based cardiac output using the FloTrac/Vigileo: a review and meta-analysis. J Cardiothorac Vasc Anesth 2009;23:401–6. [5] Critchley LA, Critchley JA. A meta-analysis of studies using bias and precision statistics to compare cardiac output measurement techniques. J Clin Monit Comput 1999;15:85–91. [6] Le Manach Y, Collins GS. Disagreement between cardiac output measurement devices: which device is the gold standard? Br J Anaesth 2016;116:451–3. [7] Critchley LA, Lee A, Ho AM-H. A critical review of the ability of continuous cardiac output monitors to measure trends in cardiac output. Anesth Analg 2010;111:1180–92. [8] Critchley LA, Yang XX, Lee A. Assessment of trending ability of cardiac output monitors by polar plot methodology. J Cardiothorac Vasc Anesth 2011;25:536–46. [9] Feldman JM. Is it a bird? Is it a plane? The role of patient monitors in medical decision making. Anesth Analg 2009;108:707–10.
[10] Harvey S, Harrison DA, Singer M, Ashcroft J, Jones CM, Elbourne D, et al. Assessment of the clinical effectiveness of pulmonary artery catheters in management of patients in intensive care (PAC-Man): a randomised controlled trial. Lancet 2005;366:472–7. [11] Phan TD, Ismail H, Heriot AG, Ho KM. Improving perioperative outcomes: fluid optimization with the esophageal Doppler monitor, a meta-analysis and review. J Am Coll Surg 2008;207:935–41. [12] Funk DJ, Moretti EW, Gan TJ. Minimally invasive cardiac output monitoring in the perioperative setting. Anesth Analg 2009;108:887–97. [13] Pinsky MR, Vincent JL. Let us use the pulmonary artery catheter correctly and only when we need it. Crit Care Med 2005;33:1119–22.
Matthieu Biais (MD, Ph.D). a,b,*, Romain Lanchon (MD) a Jean-Yves Lefrant (MD, Ph.D). c,d a Service d’Anesthe´sie et de Re´animation 3, CHU de Bordeaux, Hoˆpital Pellegrin, place Ame´lie-Raba-Le´on, 33076 Bordeaux cedex, France b Universite´ de Bordeaux, Bordeaux, France c Service des Re´animations, Division Anesthe´sie, Re´animation, Urgences, Douleur, CHU de Nıˆmes, place du Professeur-Robert-Debre´, 30029 Nıˆmes cedex 9, France d Universite´ de Nıˆmes, Nıˆmes, France *Corresponding author at: Service d’Anesthe´sie et de Re´animation 3, CHU de Bordeaux, Hoˆpital Pellegrin, place Ame´lie-Raba-Le´on, 33076 Bordeaux cedex, France E-mail addresses: [email protected] (M. Biais), [email protected] (R. Lanchon), [email protected] (J.-Y. Lefrant)