Pulmonary oxygen consumption: a hypothesis to explain the increase in oxygen consumption of low birth weight infants with lung disease.
OBJECTIVE
We determined pulmonary oxygen consumption (VO2lung) in low-birthweight infants with acute lung disease to help explain the greater whole-body oxygen consumption (VO2wb) in these infants with than in those without lung disease.


METHODS
Eleven infants (birth weight 1,076+/-364 g; gestational age 28+/-3 weeks) undergoing mechanical ventilation for respiratory distress syndrome were studied in their first week of life. We measured VO2wb by indirect calorimetry and simultaneously determined systemic oxygen uptake (VO2Fick) as the product of cardiac output (echocardiography) and the arterial-mixed venous oxygen content difference (cooximetry) assuming that VO2wb-VO2Fick accounts for VO2lung. Right atrial blood samples were used to determine mixed venous oxygenation, and infants were excluded if samples returned saturations greater than 89%.


RESULTS
VO2lung was 1.92+/-1.74 ml x kg(-1) x min(-1), representing 25% of their VO2wb (7.58+/-1.48 ml x kg(-1) x min(-1)). VO2lung was not correlated with clinical measures of acute disease severity. However, infants with the most severe changes on follow-up radiography (Edwards score 5 as assessed by radiologist blinded for VO2 data) all had a VO2lung level greater than 2.0 ml x kg(-1) x min(-1).


CONCLUSIONS
VO2lung can account for the elevated metabolic rate in low-birthweight infants with lung injury. We speculate that this reflects in part inflammatory pulmonary processes and may herald chronic lung disease.
Schulze
A
A
Division of Neonatology, Department of Obstetrics and Gynecology, Ludwig Maximilian University, Munich, Germany.
Abubakar
K
K
Gill
G
G
Way
R C
RC
Sinclair
J C
JC
D000208:Acute Disease; D001724:Birth Weight; D002153:Calorimetry, Indirect; D002245:Carbon Dioxide / Q000097:blood; D002302:Cardiac Output; D002908:Chronic Disease; D004734:Energy Metabolism; D005260:Female; D005865:Gestational Age; D006801:Humans; D006819:Hyaline Membrane Disease / Q000000981:diagnostic imaging / Q000276:immunology / Q000378:metabolism* / Q000503:physiopathology / Q000628:therapy; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007235:Infant, Premature, Diseases / Q000000981:diagnostic imaging / Q000276:immunology / Q000378:metabolism* / Q000503:physiopathology / Q000628:therapy; D007249:Inflammation; D008168:Lung / Q000378:metabolism*; D008171:Lung Diseases / Q000000981:diagnostic imaging / Q000276:immunology / Q000378:metabolism* / Q000503:physiopathology / Q000628:therapy; D008297:Male; D010092:Oximetry; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption; D011859:Radiography; D012121:Respiration, Artificial; D012720:Severity of Illness Index; D016037:Single-Blind Method; D013997:Time Factors
D002245:Carbon Dioxide; D010100:Oxygen