Determinants of survival in pediatric continuous hemofiltration

Abstract

Continuous hemofiltration (CH) is being used in increasing numbers of pediatric intensive care unit patients. Experience with 114 CH treatments in 98 critically ill children from March 1988 to March 1993 is presented in this study. Ages ranged from 1 day to 23 yr (mean ± SE = 7.1 ± 0.7 yr), and 54% of patients were male. Seventeen percent of all treatments were performed in neonates under 1 month of age. The most common primary diagnoses were sepsis and adult respiratory distress syndrome (11 patients each), liver transplantation and hypoplastic left heart syndrome (10 patients each), and hemolytic uremic syndrome (9 patients). The most frequent indications for CH were fluid overload and acute renal failure (42% each). Choices for CH included: continuous arteriovenous hemofiltration (CAVH, 50%), continuous arteriovenous hemodiafiltration (CAVH-D, 23%), continuous venovenous hemofiltration (CVVH, 18%), and continuous venovenous hemodiafiltration (CVVH-D, 9%). Choices for anticoagulation included: none (47%), regional (49%), and systemic (4%). Treatment duration ranged from 1 to 25 days (mean = 5.3 ± 0.4 days). Mean filter life span for 363 filters was 0.94 ± 0.1 filters/patient per day. Despite an overall survival rate of 43%, survival to discharge varied greatly (0 to 100%) among the 24 diagnostic groups: tumor lysis syndrome and systemic lupus erythematosus (3/3 patients each, 100%) hemolytic uremic syndrome (8/9 patients, 89%). This compares with: bone marrow transplantation (0/16 patients, 0%), hypoplastic left heart syndrome (2/10 patients, 20%), and leukemia (1/4 patients, 25%). Survival to hospital discharge was better in patients who did not receive pressors (P < 0.005) and in patients treated with combined ultrafiltration and dialysis (CAVH-D, CVVH-D) compared with ultrafiltration alone (CAVH, CVVH) (P < 0.005), but was not notably affected by patient age, sex, use of anticoagulation, filter life span, blood pump-assisted versus spontaneous CH, or duration of therapy. Filter life span was not affected by use of anticoagulation, but was remarkably longer in patients with arteriovenous versus venovenous CH (P < 0.004). It was concluded that: (1) empirical anticoagulation of patients treated with CH is not necessary; (2) children with a minority of underlying diseases and those requiring pressor support at initiation of CH appear to have relatively poor survival rates despite the technically effective use of CH; and (3) the addition of countercurrent dialysis to routine CH may enhance patient survival to hospital discharge.