Poelaert, Jan

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http://scv.sagepub.comAnesthesia Seminars in Cardiothoracic and VascularDOI: 10.1177/108925320601000118  2006; 10; 111 Semin Cardiothorac Vasc AnesthJan Poelaert  The Failing Heart Under Stress: Echocardiography is an Essential Monitoring Tool in the Intensive Care Unithttp://scv.sagepub.com/cgi/content/abstract/10/1/111 The online version of this article can be found at: Published by:http://www.sagepublications.com can be found at:Seminars in Cardiothoracic and Vascular Anesthesia Additional services and information for  http://scv.sagepub.com/cgi/alerts Email Alerts: http://scv.sagepub.com/subscriptions Subscriptions: http://www.sagepub.com/journalsReprints.navReprints:  http://www.sagepub.com/journalsPermissions.navPermissions:  http://scv.sagepub.com/cgi/content/abstract/10/1/111#BIBLSAGE Journals Online and HighWire Press platforms): (this article cites 28 articles hosted on the Citations © 2006 . All rights reserved. Not for commercial use or unauthorized distribution. at UNIV GENT/UZGENT OP8 on March 22, 2007 http://scv.sagepub.comDownloaded from significant reduction of the pumping activity ofone or both ventricles. Table 1 depicts variouscauses of pump failure. Circulatory failure canalso be caused by sepsis and septic shock, whichhave been clearly related with congestive heartfailure, even in patients without previous my-ocardial infarction.2 An imbalance between pre-load and afterload is another example of whereassessment of basic hemodynamics plays a piv-otal role.3Three variables determine left ventricular sys-tolic performance: (1) the Frank Starling mecha-nism, provided by pressures and volumes, (2)heart rate, and (3) contractility as a load-inde-pendent descriptor of systolic function. Pressuremonitoring is still routinely used when a patientwith hemodynamic deterioration is evaluated.Nevertheless, pressures only provide a rudimen-tary approach of the three physiologically impor-tant features of contractility, preload, and after-load. The combined use of pressures and flows,obtained with Doppler echocardiography, pro-vides elementary and far more interesting data onhemodynamics than pressures alone. The assess-ment of hemodynamics in the ICU is stronglybased on these characteristics and is the maintopic of this review.Assessment of Preloading ConditionsAs already stated, intracardiac and intrapul-monary pressures provide only a limited part ofthe correct assessment of preload. Nevertheless, itis important to correctly characterize preloadingconditions, especially in patients with large fluidshifts. Optimal preload is the first measure to betaken when stabilizing a hemodynamically unsta-ble patient, and this is a relatively inexpensivemeasure. Pressure can definitively be estimatedby Doppler echocardiography, as described pre-viously in the literature.4-10The short-axis view with two-dimensionalechocardiography offers an immediate visualiza-Echocardiography has evolved to become amajor diagnostic tool in the practice of cardi-ology. In critically ill patients, however, echocar-diography has progressively become a corner-stone in hemodynamic management and deci-sion-making. The transthoracic and trans-esophageal approaches are of tremendous help inthe daily intraoperative decision-making that oc-curs in all hemodynamically devastating surgery.In addition, these techniques are even more help-ful in the intensive care unit (ICU), where a rapidand correct diagnosis of the cause of the hemo-dynamic instability is warranted. Evaluation of hemodynamics with echocar-diography is unthinkable without pulsed wave,continuous wave, and tissue Doppler. The expla-nation and differences between these techniquesis beyond the scope of this paper, but the readeris referred to review articles.1Circulatory failure is most often due to car-diac (ventricular) failure, usually evidenced as aEchocardiography has been evolving to play a pivotal role inhemodynamic management, both intraoperatively and at thebedside. A full assessment of hemodynamics necessitates theuse of all of the options available on modern echocardio-graphs. This introductory review provides insight into threeimportant issues of hemodynamic monitoring by echocardio-graphy: evaluation of preloading conditions, assessment ofsystolic function, and contractility and estimation of afterload.Mastering these three features will help in a minimally inva-sive approach of hemodynamic instability.Seminars in Cardiothoracic and Vascular Anesthesia, Vol 10, No 1 (March), 2006: pp 111–115 111The Failing Heart Under Stress:Echocardiography is an Essential MonitoringTool in the Intensive Care UnitJan Poelaert, MD, PhDFrom the Cardiac Anesthesia and Postoperative CardiacSurgical ICU, University Hospital Ghent, Gent, BelgiumThis work was supported by an unrestricted grant of theInternational Research Center, Ghent University, Gent,BelgiumAddress reprint requests to Jan Poelaert, MD, PhD, CardiacAnesthesia and Postoperative Cardiac Surgical ICU, UniversityHospital Ghent, De Pintelaan 185, 9000 Gent, Belgium; e-mail: jan.poelaert@ugent.be©2006 Westminster Publications, Inc., 708 Glen Cove Avenue,Glen Head, NY 11545, USA © 2006 . All rights reserved. Not for commercial use or unauthorized distribution. at UNIV GENT/UZGENT OP8 on March 22, 2007 http://scv.sagepub.comDownloaded from tion of the filling of the left and right ventricles.The presence of kissing walls of the left ventriclein an adequately sedated patient, in the absenceof sympathetic stimulation and without any sup-port of inotropic drugs, is the signature of a lowfilling status.11 In that case, a fluid challenge isthe first choice of therapy, which can be readilyobtained in a sedated patient by raising the legs.Several drawbacks of the short-axis view as ameasure of preloading condition have to be takeninto account. The presence of regional wall mo-tion abnormalities will certainly hamper the cor-rect interpretation of the preloading conditionsrelated to the end-diastolic area of the left ventri-cle. Another issue is the presence of dilated car-diomyopathy. In this particular case, passive legraising could be a dangerous maneuver.12,13However, ventilation-induced systolic variation ofpressure or flow across the aortic valve could beof significant help, suggesting a sign of fluid re-sponsiveness. The value of systolic pressure and stroke vol-ume variation is well established and has been as-sessed by many authors.14-16 Cyclic altering of in-trathoracic pressure induces this variation of pres-sure and flow. It was clearly shown that the vari-ation of the transaortic flow velocity integral in-creased considerably with a graded hemorrhagein an animal experimental setting.17Finally, the variation of the inferior vena cavaflow with transthoracic echocardiography and su-perior caval vein flow with transesophagealechocardiography18 during (spontaneous) venti-lation is another signature of low preloading con-ditions. Nevertheless, inferior caval vein collapsi-bility works only in conventionally ventilated pa-tients and not in patients who are receiving high-frequency oscillatory ventilation.19ContractilityVentricular function can be described in terms ofload-dependent and load-independent variables(Table 2).20,21 As described previously,22,23 theshort-axis view of the left ventricle is the basicview and start of each echocardiographic exami-nation. This basic view allows the assessment ofthree important features of hemodynamics: glob-al contractility, left ventricular preload, and thepresence of regional wall motion abnormalities.Poelaert112Table 1. Examples of Causes of Pump Failure of One or Both Ventricles• Ischemic heart disease• Myocardial disease• Pericardial disease• Pressure overloado Left ventricle: high afterload: stress, high dose ofvasopressoro Right ventricle: pulmonary hypertension,pulmonary emboli, adult respiratory distresssyndrome; asthma bronchial, chronic obstructivelung disease exacerbation• Volume overloado Presence of intracardiac shunts (atrial septumdefect, ventricular septal defect)Table 2. Load-Dependent and Load-IndependentDescriptors of Ventricular FunctionLoad-dependent variables• Ejection fraction: EF = (LVEDA–LVESA)/LVEDA• Cardiac index: CO = (HR x SV)/BSA• Stroke volume: SV = TVI x CSA• (+dP/dt)max, when a leakage of the mitral or aorticvalve is present• Myocardial performance index20: MPI = (ICT +IRT)/ET• S wave (tissue Doppler imaging)21Load-independent variables• Velocity of circumferential fiber shortening• Preload-adjusted maximal power and preload-adjustedpeak power• Maximal elastance Emax• Preload recruitable stroke work• (dP/dt)max/EDVEF, ejection fraction of the left ventricle (%); LVEDA, leftventricular end-diastolic area, taken at the short axis view(cm2); LVESA, left ventricular end-systolic area (same view asLVEDA)(cm2); CO, cardiac output (L/min.m2); HR, heart rate(beats/min); SV, stroke volume (mL); BSA, body surface area(m2); TVI, time velocity integral (cm); CSA, cross-sectionalarea (cm2); MPI, myocardial performance index; ICT, isovo-lumic contraction time (milliseconds); IRT, isovolumic relax-ation time (milliseconds); ET, ejection time (milliseconds);(dP/dt)max/EDV, maximal dP/dt, corrected for end-diastolicvolume (mm Hg/s.cm3). © 2006 . All rights reserved. Not for commercial use or unauthorized distribution. at UNIV GENT/UZGENT OP8 on March 22, 2007 http://scv.sagepub.comDownloaded from Although the variables explained in Table 2 pro-vide more extensive information, it is evident thatthese parameters also have more scientific meritsthan direct routine monitoring. In clinical practice, the intensivist relies moreon direct observation to clearly identify differ-ences between normal function, hypercontractileventricles, and ventricles with decreased function.In any hemodynamic deterioration, an arterialpressure is warranted, offering information con-cerning global systolic function, stroke volume,and filling. If hypotension is combined with a nor-mal left ventricular function in a hemodynami-cally unstable patient, it is evident that othercauses of this hemodynamic deterioration shouldbe explored. Furthermore, hypotension in con-junction with a hyperdynamic left ventricle sug-gests either an overdose of inotropic support orlow filling status. Finally, hypotension and decreased left ven-tricular function warrants further echocardio-graphic investigation, as described in Figure 1. Inany case, right ventricular function also has to beassessed. A complete echocardiogram, compris-ing evaluation of regional wall motion abnormal-ities and valvular function is then justified. After initial treatment, guided by both arteri-al pressure tracing and an echocardiogram, morecontinuous hemodynamic monitoring can be es-tablished, when appropriate. A central venouscatheter, including oximetry, or a pulmonaryartery catheter, including mixed venous oxime-try, could further help to monitor the critically illpatient.AfterloadThe combined use of arterial pressure monitoringand echocardiography provides important infor-mation for determining left ventricular systolicEchocardiography is an Essential Monitoring Tool in the ICU 113Figure 1. Working scheme to utilize echocardiography as a monitoring tool in a hypotensive patient. TTE, transthoracic echocardiography; TEE, transesophageal echocardiography; LV, left ventricle; RV, right ventricle. © 2006 . All rights reserved. Not for commercial use or unauthorized distribution. at UNIV GENT/UZGENT OP8 on March 22, 2007 http://scv.sagepub.comDownloaded from function. In particular, various contractility in-dices and afterload can be readily described bycombining pressure and flow, derived easily fromthese two features. Because total arterial compliance is shown tobe an important cardiovascular risk factor,24 theimportance of determination of afterload cannotbe denied. The main determinants of afterload aresystemic vascular resistance and total arterial com-pliance, which reflect the static and pulsatile com-ponents of arterial load, respectively.25,26 Recently,Heerman et al27 demonstrated that thoracic aor-tic compliance can be determined off-line by usinglocal pressure and flow and by applying the arct-angent model of Langewouters28,29 in vivo. ConclusionsAlthough echocardiography provides significanthelp in the diagnosis of most cardiac diseases, thecombined use of pressure values and echoDoppler offers pivotal information on hemody-namics in a rapid manner. The weakest factor isprobably estimation of preload in a dilated leftventricle, although a positive answer to the rapidfilling test with a decrease of the systolic respira-tory flow variation across the aortic valve is in-dicative of fluid responsiveness. It is important tocombine systemic pressure values and flow acrossthe aortic valve to obtain extensive informationabout systolic function parameters and afterload-ing conditions in critically ill patients.References1. Garcia M, Thomas J, Klein A: New Doppler echocardio-graphic applications for the study of diastolic function.Review article. J Am Coll Cardiol 32:865-875, 1998.2. Vasan RS, Sullivan LM, Roubenoff R, et al: Inflammatorymarkers and risk of heart failure in elderly subjects withoutprior myocardial infarction: The Framingham Heart Study.Circulation 107:1486-1491, 2003.3. Mebazaa A, Karpati P, Renaud E, et al: Acute right ven-tricular failure—from pathophysiology to new treatments.Intensive Care Med 30:185-196, 2004.4. Appleton C, Galloway J, Gonzalez M, et al: Estimation ofleft ventricular filling pressures using two-dimensional andDoppler echocardiography in adult patients with cardiacdisease. Additional value of analyzing left atrial size, leftatrial ejection fraction and the difference in duration ofpulmonary venous and mitral flow velocity at atrial con-traction. J Am Coll Cardiol 22:1972-1982, 1993.5. Ito T, Suwa M, Otake Y, et al: Left ventricular Doppler fill-ing pattern in dilated cardiomyopathy: Relation to hemo-dynamics and left atrial function. J Am Soc Echocardiogr10:518-525, 1997.6. Jardin F, Fourme T, Page B, et al: Persistent preload de-fect in severe sepsis despite fluid loading: A longitudinalechocardiographic study in patients with septic shock.Chest 116:1354-1359, 1999.7. Kuecherer HF, Muhiudeen IA, Kusumoto FM, et al:Estimation of mean left atrial pressure from trans-esophageal pulsed Doppler echocardiography of pul-monary venous flow. Circulation 82:1127-1139, 1990.8. Nagueh S, Middleton K, Kopelen H, et al: Doppler tissueimaging: A noninvasive technique for evaluation of leftventricular relaxation and estimation of filling pressures. J Am Coll Cardiol 30:1527-1533, 1997.9. Schiller N: Pulmonary artery pressure estimation byDoppler and two-dimensional echocardiography. CardiolClin 8:277-287, 1990.10. Vieillard Baron A, Schmitt JM, Beauchet A, et al: Early pre-load adaptation in septic shock? A transesophagealechocardiographic study. Anesthesiology 94:400-406,2001.11. Leung JM, Levine EH: Left ventricular end-systolic cavityobliteration as an estimate of intraoperative hypovolemia.Anesthesiology 81:1102-1109, 1994.12. Borow KM, Neumann A, Marcus RH, et al: Effects of si-multaneous alterations in preload and afterload measure-ments of left ventricular contractility in patients with di-lated cardiomyopathy: Comparisons of ejection phase, iso-volumetric and end-systolic force-velocity indexes. J AmColl Cardiol 20:787-795, 1992.13. De Hert S, Vander Linden P, Ten Broecke P, et al: Assess-ment of length-dependent regulation of myocardial func-tion in coronary surgery patients using transmitral flow ve-locity patterns. Anesthesiology 93:374-381, 2000.14. Coriat P, Vrillon M, Perel A, et al: A comparison of systolicblood pressure variations and echocardiographic estimatesof end-diastolic left ventricular size in patients after aorticsurgery. Anesth Analg 78:46-53, 1994.15. Perel A, Pizov R, Cotev S: Systolic blood pressure variationis a sensitive indicator of hypovolaemia in ventilated dogssubjected to graded hemorrhage. Anesthesiology 67:498-502, 1987.16. Tavernier B, Makhotine O, Lebuffe G, et al: Systolic pres-sure variation as a guide to fluid therapy in patients withsepsis-induced hypotension. Anesthesiology 89:1313-1321,1998.17. Slama M, Ahn J, Varagic J, et al: Long-term left ventricularechocardiographic follow-up of SHR and WKY rats: Effectsof hypertension and age. Am J Physiol Heart Circ Physiol286:H181-185, 2004.18. Vieillard-Baron A, Chergui K, Rabiller A, et al: Superiorvena caval collapsibility as a gauge of volume status in ven-tilated septic patients. Intensive Care Med 30:1734-1739,2004.19. Hruda J, Rothuis EG, van Elburg RM, et al: Echo-cardiographic assessment of preload conditions does nothelp at the neonatal intensive care unit. Am J Perinatol20:297-303, 2003.Poelaert114 © 2006 . All rights reserved. Not for commercial use or unauthorized distribution. at UNIV GENT/UZGENT OP8 on March 22, 2007 http://scv.sagepub.comDownloaded from 20. Poelaert J, Heerman J, Schupfer G, et al: Estimation of my-ocardial performance in CABG patients. Acta AnaesthesiolScand 48:973-979, 2004.21. Amà R, Segers P, Roosens C, et al: Effects of load on sys-tolic mitral annular velocity by tissue Doppler imaging.Anesthesia Analgesia 99:332-338, 2004.22. Poelaert J, Schmidt C, Colardyn F: Transoesophagealechocardiography in the critically ill. Anaesthesia 53:55-68, 1998.23. Poelaert JI, Schupfer G: Hemodynamic monitoring utilizingtransesophageal echocardiography: The relationshipsamong pressure, flow, and function. Chest 127:379-390,2005.24. Stefanadis C, Dernellis J, Tsiamis E, et al: Aortic stiffness asa risk factor for recurrent acute coronary events in patientswith ischaemic heart disease. Eur Heart J 21:390-396,2000.25. Molino P, Cerutti C, Juline C, et al: Beat-to-beat estima-tion of windkessel model parameters in conscious rats. AmJ Physiol Heart Circ Physiol 274:H171-177, 1998.26. Segers P, Verdonck P, Deryck Y, et al: Pulse pressuremethod and the area method for the estimation of total ar-terial compliance in dogs: Sensitivity to wave reflection in-tensity. Ann Biomed Engin 27:480-485, 1999.27. Heerman JR, Segers P, Roosens CD, et al: Echo-cardiographic assessment of aortic elastic properties withautomated border detection in an ICU: In vivo applicationof the arctangent Langewouters’ model. Am J Physiol HeartCirc Physiol 288:H2504-2511, 2005.28. Langewouters G, Wesseling K, Goedhard W: The staticelastic properties of 45 human thoracic and 20 abdominalaortas in vitro and the parameter of a new model. J Biomechanics 17:425-435, 1984.29. Langewouters G, Wesseling K, Goedhard W: The pressuredependent dynamic elasticity of 35 thoracic and 16 ab-dominal human aortas in vitro described by a five compo-nent model. J Biomechnics 18:613-620, 1985.Echocardiography is an Essential Monitoring Tool in the ICU 115 © 2006 . All rights reserved. Not for commercial use or unauthorized distribution. at UNIV GENT/UZGENT OP8 on March 22, 2007 http://scv.sagepub.comDownloaded from 

The failing heart under stress: echocardiography is an essential monitoring tool in the Intensive Care Unit

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The failing heart under stress: echocardiography is an essential monitoring tool in the Intensive Care Unit

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Ghent University Academic Bibliography