[Left ventricular-arterial coupling in the resuscitation of refractory septic shock]

Abstract

Objective: To explore the role of left ventricular-arterial coupling in the resuscitation of refractory septic shock.

Methods: A total of 58 patients with refractory septic shock admitted from January 2010 to July 2011 were retrospectively studied. Hemodynamic data, arterial lactate concentration and APACHEII (acute physiology & chronic health evaluation II) score at the beginning of and 24 hours after cardiac output monitoring, as well as the outcome of Day 28 post-diagnosis were recorded. Stroke volume index (SVI), cardiac index (CI) and global end diastolic volume index (GEDVI) were obtained through transpulmonary thermodilution technique by a pulse induced continuous cardiac output (PiCCO) system. Left ventricular end systolic volume index (LVESVI) was approximated to (GEDVI/4-SVI) while effective arterial elastance index/ventricular end systolic elastance index (EaI/EesI) was approximated to LVESVI/SVI.

Results: (1) APACHEII score at the 24th hour, 24 hs lactate clearance rate and 24 hs Ea/Ees variation (ΔEa/Ees) were higher in non-survivors than those in survivors; (2) binary Logistic regression analysis showed that ΔEa/Ees and APACHEII score at the 24th hour were the independent risk factors of mortality for refractory septic shock. And the OR value of ΔEa/Ees was higher than that of APACHEII score (2.04 vs 1.63). Their areas of ROC curve were 0.705 (95%CI 0.569 - 0.841, P = 0.007) and 0.939 (95%CI 0.878 - 1.000, P = 0.000) respectively; (3) all hemodynamic parameters at the beginning had no difference between ΔEa/Ees > 0 and ΔEa/Ees ≤ 0 groups. CI, SVI, EGDT (early goal-directed therapy) compliance rate at the 24th hour in the ΔEa/Ees > 0 group were lower than those in the ΔEa/Ees ≤ 0 group. The effective arterial elastance index (EaI) at the 24th hour and the mortality rate of Day 28 in the ΔEa/Ees > 0 group were higher than those in the ΔEa/Ees ≤ 0 group; (4) during the 24 hs treatment, ΔEa/Ees was correlated negatively with the variations of CI, SVI, EesI and lactate clearance rate and positively with the variations of heart rate, GEDVI, systolic vascular resistance index and EaI.

Conclusion: ΔEa/Ees may be used as an excellent marker of predicting the outcome of refractory septic shock. Lowing Ea/Ees in resuscitation has beneficial effects on EGDT compliance, lactate clearance and outcome.