Effects of continuous haemofiltration vs intermittent haemodialysis on systemic haemodynamics and splanchnic regional perfusion in septic shock patients: a prospective, randomized clinical trial

Background. Parameters of splanchnic regional perfusion, like intramucosal pH (pHi) and pCO(2) (pCO(2)i). may predict outcome in septic shock patients . Continuous venovenous haemofiltration (CVVH) has been considered benefici al in haemodynamically unstable septic shock patients. In a prospective, ra ndomized, clinical study, we investigated whether CVVH, in comparison to in termittent haemodialysis (IHD), is able to improve splanchnic regional perf usion in critically ill patients. Methods. Thirty septic shock patients with acute renal failure were randomi zed to either CVVH (n = 20) or IHD (n = 10) groups for renal replacement th erapy. Patient characteristics at baseline were not different in terms of s everity of illness (APACHE II scores), haemodynamics, and pHi/pCO(2)i value s. Systemic haemodynamics, oxygen transport variables, and splanchnic regio nal perfusion parameters were measured at 0.5, 2, 4 and 24 h after initiati on of renal replacement therapy. There were no major changes in vasopressor support throughout the 24-h study period. Results. In contrast to IHD, CVVH caused a decrease in heart rate (-3 +/- 1 1 vs +9 +/- 8/min, P < 0.01) and an increase in systolic blood pressure (+1 2 <plus/minus> 1 vs -5 +/- 17 mmHg, P < 0.05) after 2 h. After 24 h, increa sed systemic vascular resistance was found in the CVVH group in comparison with the IHD group (+312 <plus/minus> 755 vs -29 +/- 89 dyne/cm(5), P < 0.0 5) and was accompanied by a decrease in cardiac output (-1.54 <plus/minus> 1.4 vs -0.25 +/- 0.9 l/min, P < 0.01). However pHi values remained constant throughout the 24-h study period in both groups and were not different bet ween the groups (CVVH 7.19 <plus/minus> 0.1 vs IHD 7.19 +/- 0.1, n.s.) as d id the pCO(2)i values (CVVH +7 +/- 17 0 +/- 15 mmHg, n.s.) and pCO(2) gap v alues (CVVH +6 +/- 15 vs IHD +5 +/- 12 mmHg, n.s.). Conclusions. Despite different changes of systemic haemodynamics between CV VH and IHD, CVVH did not improve parameters of splanchnic regional perfusio n like pHi, pCO(2)i or pCO(2) Sap in septic shock patients.