Relative deficiency of arginine vasopressin in children after cardiopulmonary bypass.
OBJECTIVE
To describe changes in plasma arginine vasopress in concentration in children following cardiopulmonary bypass and determine whether, in some patients, plasma arginine vasopressin remains relatively low despite hemodynamic instability.


METHODS
Prospective observational study.


METHODS
Pediatric intensive care unit at a tertiary care university hospital.


METHODS
One hundred twenty patients ≤ 18 yrs of age undergoing open heart surgery requiring cardiopulmonary bypass at Children's Hospital of Michigan between January 2008 and January 2009.


METHODS
Blood samples were collected before cardiopulmonary bypass and 4, 24, and 48 hrs after cardiopulmonary bypass for measurement of plasma arginine vasopressin concentration.


RESULTS
Mean plasma arginine vasopressin (pg/mL) for all patients was 21 ± 63 before cardiopulmonary bypass and 80 ± 145, 43 ± 79, and 19 ± 25 at 4, 24, and 48 hrs, respectively, after cardiopulmonary bypass. Patients with plasma arginine vasopressin below the lower quartile (< 9.2 pg/mL) at 4 hrs after cardiopulmonary bypass (n = 29), labeled group A, were examined separately and compared with the rest of the study population, labeled group B. Mean plasma arginine vasopressin was 4.9 ± 2.6 in group A at 4 hrs after cardiopulmonary bypass, statistically unchanged from its baseline mean plasma arginine vasopressin of 5.0 ± 10.4 (p = .977). Mean plasma arginine vasopressin in group B was 104 ± 160 at 4 hrs after cardiopulmonary bypass. Mean plasma arginine vasopressin of group A was also significantly lower as compared with group B before and 24 and 48 hrs after cardiopulmonary bypass. Hemodynamics, inotrope score, and serum sodium did not differ between groups at any time point. Plasma arginine vasopressin was measured immediately before exogenous arginine vasopressin administration in 10 patients; only those (n = 3) with hemodynamic instability and relatively low plasma arginine vasopressin concentration (< 9.2 pg/mL) had notable hemodynamic improvement.


CONCLUSIONS
In some children undergoing open heart surgery, plasma arginine vasopressin concentration is relatively low at baseline and remains low after cardiopulmonary bypass regardless of hemodynamic stability and serum osmolality. These children are likely the optimal candidates for exogenous arginine vasopressin should hemodynamic compromise occur.
Mastropietro
Christopher W
CW
Department of Pediatrics, Division of Critical Care, Wayne State University, in affiliation with Children's Hospital of Michigan, Detroit, MI, USA. cmastrop@med.wayne.edu
Rossi
Noreen F
NF
Clark
Jeff A
JA
Chen
Haiping
H
Walters
Henry
H
Delius
Ralph
R
Lieh-Lai
Mary
M
Sarnaik
Ashok P
AP
D001127:Arginine Vasopressin / Q000097:blood / Q000172:deficiency*; D006348:Cardiac Surgical Procedures / Q000009:adverse effects; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D002675:Child, Preschool; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007223:Infant; D008297:Male; D011446:Prospective Studies; D013997:Time Factors
D001127:Arginine Vasopressin