Bendjelid, Karim

Romand, Jacques-A

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ness than dynamic parameters. Faehnrichet al. [2] have recently demonstrated effec-tively in an animal study that the respirato-ry change in mitral flow under positivepressure ventilation becomes nonexistentwhen cardiac tamponade is present. In thisparticular case the hypotended patientcould be considered a nonresponder to afluid challenge by stroke volume variationindices, when giving him more fluidsshould be useful to increase cardiac outputand/or mean arterial pressure.Second, Starling’s law has shown thatpreinfusion cardiac preload, ventricularcontractility, and afterload all influence thestroke volume response to volume load.Nevertheless, in the particular case of a patient with a left ventricular systolic dys-function, clinicians should keep in mindthat positive pressure ventilation acts as acirculatory pump [3] that relatively im-proves contractility and decreases after-load.Third, although we agree that the ques-tion “does our fluid challenge effectivelyincrease patient cardiac preload?” is essen-tial to explain and validate the physiologi-cal background of a cardiac preload index[4], the answer to this question has no consequence for clinical practice if the index has been validated to be an accurateparameter for predicting the response ofcardiac output and/or mean arterial pres-sure after volume infusion in all patho-logical situations. Practically, clinicianswant to determine not the variation in theend-diastolic volume but rather whetherthe mean arterial pressure will increase (related to increase in cardiac output) aftervolume infusion.Finally, cardiac responsiveness to vol-ume loading depends on different Starlingcurves (each reflecting a different inotropicstate of the ventricles) and on the ventricu-lar interdependence [5]. Therefore the opti-mal index to predict the fluid responsive-ness, in all pathological situations, must assess these two estimations. As stated inour review [1], there are presently only fewworks clearly relevant to the specific fluidresponsiveness, and the most useful param-eters for predicting cardiac output responseto fluid challenge in mechanically ventilat-ed patients are the dynamics parameters.However, because the limits of these indi-ces have not yet been demonstrated in par-ticular cases, and the echocardiographyshould be revitalized by three-dimensionaltechnique, it seem to us that the challengecontinues.References1. Bendjelid K, Romand JA (2003) Fluid responsiveness in mechanicallyventilated patients: a review of indicesused in intensive care. Intensive CareMed 29:352–3602. Faehnrich JA, Noone RB Jr, White WD,Leone BJ, Hilton AK, Sreeram GM,Mark JB (2003) Effects of positive-pres-sure ventilation, pericardial effusion,and cardiac tamponade on respiratoryvariation in transmitral flow velocities. J Cardiothorac Vasc Anesth 17:45–503. Beattie C, Guerci AD, Hall T, BorkonAM, Baumgartner W, Stuart RS, PetersJ, Halperin H, Robotham JL (1991)Mechanisms of blood flow during pneu-matic vest cardiopulmonary resuscita-tion. J Appl Physiol 70:454–4654. Tavernier B, Makhotine O, Lebuffe G,Dupont J, Scherpereel P (1998) Systolicpressure variation as a guide to fluidtherapy in patients with sepsis-inducedhypotension. Anesthesiology89:1313–13215. Jardin F (2003) Ventricular interdepen-dence: how does it impact on hemody-namic evaluation in clinical practice?Intensive Care Med 29:361–363This reply refers to the comment availableat http://dx.doi.org/10.1007/s00134-003-1846-4K. Bendjelid (✉) · J.-A. RomandSurgical Intensive Care Division,Geneva University Hospital,1211 Geneva 14, Switzerlande-mail: Karim.Bendjelid@hcuge.chTel.: +41-22-3827452Fax: +41-223827455Intensive Care Med (2003) 29:1397DOI 10.1007/s00134-003-1777-0 C O R R E S P O N D E N C EKarim BendjelidJacques-A. RomandReply to comment on “Fluid responsiveness in mechanically ventilated patients: a review of indicesused in intensive care”Received: 26 March 2003Accepted: 30 March 2003Published online: 22 May 2003© Springer-Verlag 2003Sir: We read with interest the comments byMichard and Reuter regarding our reviewarticle entitled “Fluid responsiveness inmechanically ventilated patients: a reviewof indices used in intensive care” [1] andwould like to make the following remarksabout their comments.First, we have never stated that cardiacpreload and fluid responsiveness (cardiacresponsiveness to volume loading) are synonyms. Moreover, we disagree withthese authors that improvement in techno-logical measurements of selected static cardiac preload indices should not increasethe predictive value of fluid responsive-ness. As they highlight in their letter, wepropose three-dimensional echocardiogra-phy to meet this challenge. We chose thistechnique as it allows the measurement ofboth ventricular volumes and contractilityand the estimation of pericardial restraint.Therefore for physiological reasons we canaccurately predict fluid responsivenesssimply by assessing baseline cardiac pre-load when the technique used allows thediscrimination of normal from failing ven-tricle (systolic and/or diastolic failure).Moreover, it seems to us that in particularcases such as cardiac tamponade (mechan-ic diastolic dysfunction) echocardiographycould be a better index of fluid responsive-

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