An analysis of oxygen consumption and oxygen delivery in euthermic infants after cardiopulmonary bypass with modified ultrafiltration.
BACKGROUND
The balance between systemic oxygen consumption (VO2) and delivery (DO2) is impaired after cardiopulmonary bypass (CPB) and is related to systemic inflammatory response syndrome. We sought to assess VO2 and DO2 and their relationship with proinflammatory cytokines after CPB with the use of modified ultrafiltration (MUF) in infants.


METHODS
Sixteen infants, aged 1-11.5 months (median, 6.3 months), undergoing hypothermic CPB with MUF were studied during the first 12 hours after arrival in the intensive care unit (ICU). The central temperature was maintained at 36.8-37.1 degrees C using external cooling or warming. VO2 was continuously measured using respiratory mass spectrometry. Arterial blood samples for the tumor necrosis factor (TNF), interleukin-6 (IL-6), and interleukin-8 (IL-8) were taken and DO2 was calculated using the Fick principle on arrival at the ICU, and 2, 4, 8, and 12 hours postoperatively. Cytokines were additionally measured after induction of anesthesia and at the end of MUF.


RESULTS
VO2 significantly decreased by 18.8% during the study period. DO2 was depressed throughout this period and reached a nadir at 8 hours (357.1 +/- 136.2 ml x min(-1) x m(-2)). The decrease in cytokines was accompanied with the decrease in VO2 despite varied relationships between the levels of each of the cytokines and VO2 measurements.


CONCLUSIONS
Our data indicate an unusual continuous decrease in VO2 during the first 12 hours after CPB in infants. Control of body temperature to maintain euthermia in addition to the use of MUF may be beneficial to the balance between VO2 and DO2 in the early postoperative period.
Li
Jia
J
Division of Cardiology, Hospital for Sick Children, Toronto, Ontario, Canada.
Hoschtitzky
Andreas
A
Allen
Meredith L
ML
Elliott
Martin J
MJ
Redington
Andrew N
AN
D001831:Body Temperature; D002303:Cardiac Output, Low / Q000097:blood / Q000503:physiopathology; D002315:Cardiopulmonary Bypass / Q000379:methods*; D016207:Cytokines / Q000097:blood*; D005260:Female; D006330:Heart Defects, Congenital / Q000601:surgery; D006801:Humans; D007036:Hypothermia, Induced; D007223:Infant; D007231:Infant, Newborn; D015850:Interleukin-6 / Q000097:blood; D016209:Interleukin-8 / Q000097:blood; D007773:Lactates / Q000097:blood; D008297:Male; D010755:Organophosphates / Q000008:administration & dosage; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption; D011183:Postoperative Complications / Q000097:blood / Q000503:physiopathology; D011184:Postoperative Period; D011292:Premedication; D018746:Systemic Inflammatory Response Syndrome / Q000517:prevention & control; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis; D014462:Ultrafiltration
D016207:Cytokines; D015850:Interleukin-6; D016209:Interleukin-8; D007773:Lactates; D010755:Organophosphates; D014409:Tumor Necrosis Factor-alpha; C004345:triclofos; D010100:Oxygen