Optimizing fluid management in critically ill patients

Groeneveld, A.B.J. [Promotor]Girbes, A.R.J. [Promotor]Beishuizen, A. [Copromotor

Global end-diastolic volume increases to maintain fluid responsiveness in sepsis-induced systolic dysfunction

Background: Sepsis-induced cardiac dysfunction may limit fluid responsiveness and the mechanism thereof remains unclear. Since cardiac function may affect the relative value of cardiac filling pressures, such as the recommended central venous pressure (CVP), versus filling volumes in guiding fluid loading, we studied these parameters as determinants of fluid responsiveness, according to cardiac function.Methods: A delta CVP-guided, 90 min colloid fluid loading protocol was performed in 16 mechanically ventilated patients with sepsis-induced hypotension and three 30 min consecutive fluid loading steps of about 450 mL per patient were evaluated. Global end-diastolic volume index (GEDVI), cardiac index (CI) and global ejection fraction (GEF) were assessed from transpulmonary dilution. Baseline and changes in CVP and GEDVI were compared among responding (CI increase ≥10% and ≥15%) and non-responding fluid loading steps, in patient with low (<20%, n = 9) and near-normal (≥20%) GEF (n = 7) at baseline.Results: A low GEF was in line with other indices of impaired cardiac (left ventricular) function, prior to and after fluid loading. Of 48 fluid loading steps, 9 (of 27) were responding when GEF <20% and 6 (of 21) when GEF ≥20. Prior to fluid loading, CVP did not differ between responding and non-responding steps and levels attained were 23 higher in the latter, regardless of GEF (P = 0.004). Prior to fluid loading, GEDVI (and CI) was higher in responding (1007 ± 306 mL/m2) than non-responding steps (870 ± 236 mL/m2) when GEF was low (P = 0.002), but did not differ when GEF was near-normal. Increases in GEDVI were associated with increases in CI and fluid responsiveness, regardless of GEF (P < 0.001).Conclusions: As estimated from transpulmonary dilution, about half of patients with sepsis-induced hypotension have systolic cardiac dysfunction. During dysfunction, cardiac dilation with a relatively high baseline GEDVI maintains fluid responsiveness by further dilatation (increase in GEDVI rather than of CVP) as in patients without dysfunction. Absence of fluid responsiveness during systolic cardiac dysfunction may be caused by diastolic dysfunction and/or right ventricular dysfunction

Relative value of pressures and volumes in assessing fluid responsiveness after valvular and coronary artery surgery

10% per step. Results: Global ejection fraction was tower and PAOP was higher after VS than CAS. In responding steps after VS (n = 9-14) PACP and volumes increased, white CVP and volumes increased in responding steps (n = 12-19) after CAS. Baseline PAOP was tower in responding steps after VS only. Hence, baseline PACP as well as changes in PACP and volumes were of predictive value after VS and changes in CVP and volumes after CAS, in receiver operating characteristic curves. After VS, PAOP and volume changes equally correlated to Cl changes. After CAS, only changes in CVP and volumes correlated to those in Cl. Conclusions: While volumes are equally useful in monitoring fluid responsiveness, the predictive and monitoring value of PAOP is greater after VS than after CAS. In contrast, the CVP is of similar value as volume measurements in monitoring fluid responsiveness after CAS. The different value of pressures rather than of volumes between surgery types is likely caused by systolic left ventricular dysfunction in VS. The study suggests an effect of systolic cardiac function on optimal parameters of fluid responsiveness and superiority of the pulmonary artery catheter over transpulmonary dilution, for haemodynamic monitoring of VS patients. (C) 2008 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserve