Hyperoxia Reduces Oxygen Consumption in Children with Pulmonary Hypertension.
High inspired oxygen concentration (FiO2> 0.85) is administered to test pulmonary vascular reactivity in children with pulmonary hypertension (PH). It is difficult to measure oxygen consumption (VO2) if the subject is breathing a hyperoxic gas mixture so the assumption is made that baseline VO2does not change. We hypothesized that hyperoxia changes VO2. We sought to compare the VO2measured by a thermodilution catheter in room air and hyperoxia. A retrospective review of the hemodynamic data obtained in children with PH who underwent cardiac catheterization was conducted between 2009 and 2014. Cardiac index (CI) was measured by a thermodilution catheter in room air and hyperoxia. VO2was calculated using the equation CI = VO2/arterial-venous oxygen content difference. Data were available in 24 subjects (males = 10), with median age 8.3 years (0.8-17.6 years), weight 23.3 kg (7.5-95 kg), and body surface area 0.9 m2(0.4-2.0 m2). In hyperoxia compared with room air, we measured decreased VO2(154 ± 38 to 136 ± 34 ml/min/m2, p = 0.007), heart rate (91 [Formula: see text] 20 to 83 [Formula: see text] 21 beats/minute, p=0.005), mean pulmonary artery pressure (41 [Formula: see text] 16 to 35 [Formula: see text] 14 mmHg, p=0.024), CI (3.6 [Formula: see text] 0.8 to 3.3 [Formula: see text] 0.9 L/min/m2, p = 0.03), pulmonary vascular resistance (9 [Formula: see text] 6 to 7 [Formula: see text] 3 WU m2, p = 0.029), increased mean aortic (61 [Formula: see text] 11 to 67 [Formula: see text] 11 mmHg, p = 0.005), pulmonary artery wedge pressures (11 [Formula: see text] 8 to 13 [Formula: see text] 9 mmHg, p = 0.006), and systemic vascular resistance (12 [Formula: see text] 6 to 20 [Formula: see text] 7 WU m2, p=0.001). Hyperoxia decreased VO2and CI and caused pulmonary vasodilation and systemic vasoconstriction in children with PH. The assumption that VO2remains unchanged in hyperoxia may be incorrect and, if the Fick equation is used, may lead to an overestimation of pulmonary blood flow and underestimation of PVRI.
Pediatric Cardiac Intensive Care, Mazankowski Alberta Heart Institute, Stollery Children's Hospital, Edmonton, Canada.|Pulmonary Hypertension Service, Mazankowski Alberta Heart Institute, Stollery Children's Hospital, Edmonton, Canada.
Long
L
Guo
Pediatric Cardiac Intensive Care, Mazankowski Alberta Heart Institute, Stollery Children's Hospital, Edmonton, Canada.|Pulmonary Hypertension Service, Mazankowski Alberta Heart Institute, Stollery Children's Hospital, Edmonton, Canada.|Children's Heart Center, Kokilaben Dhirubhai Ambani Hospital, Mumbai, India.
Prashant
P
Bobhate
Pediatric Cardiac Intensive Care, Mazankowski Alberta Heart Institute, Stollery Children's Hospital, Edmonton, Canada.|Pulmonary Hypertension Service, Mazankowski Alberta Heart Institute, Stollery Children's Hospital, Edmonton, Canada.|Pediatric Cardiology, Amrita School of Medicine, Amrita Vishwa Vidyapeetham University, Kochi, Kerala, India.
Shine
S
Kumar
Pediatric Cardiac Intensive Care, Mazankowski Alberta Heart Institute, Stollery Children's Hospital, Edmonton, Canada.|Pulmonary Hypertension Service, Mazankowski Alberta Heart Institute, Stollery Children's Hospital, Edmonton, Canada.
Karunakar
K
Vadlamudi
Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Canada.
Tarek
T
Kaddoura
Department of Computing Science, University of Alberta, Edmonton, Canada.|Electrical and Computer Engineering in Medicine Group, University of British Columbia and BC Children's Hospital, Vancouver, BC, Canada.
Mohamed
M
Elgendi
Pediatric Cardiac Intensive Care, Mazankowski Alberta Heart Institute, Stollery Children's Hospital, Edmonton, Canada.|Pulmonary Hypertension Service, Mazankowski Alberta Heart Institute, Stollery Children's Hospital, Edmonton, Canada.|Pediatric Anesthesia, Mazankowski Alberta Heart Institute, Stollery Children's Hospital, Edmonton, Canada.
Paula
P
Holinski
Pediatric Cardiology, Mazankowski Alberta Heart Institute, Stollery Children's Hospital, Edmonton, Canada.
James Y
JY
Coe
Pediatric Cardiology, Mazankowski Alberta Heart Institute, Stollery Children's Hospital, Edmonton, Canada.
Jennifer
J
Rutledge
Pediatric Cardiac Intensive Care, Mazankowski Alberta Heart Institute, Stollery Children's Hospital, Edmonton, Canada. iadatia@ualberta.ca.|Pulmonary Hypertension Service, Mazankowski Alberta Heart Institute, Stollery Children's Hospital, Edmonton, Canada. iadatia@ualberta.ca.|Stollery Children's Hospital, Room 3A3.39, Walter C Mackenzie Health Sciences Center, 8440 112 St, Edmonton, AB, T6G 3B7, Canada. iadatia@ualberta.ca.
Ian
http://orcid.org/0000-0001-7669-6444
I
Adatia
D000293:Adolescent; D001784:Blood Gas Analysis; D006328:Cardiac Catheterization; D002302:Cardiac Output / Q000502:physiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D018496:Hyperoxia / Q000503:physiopathology*; D006976:Hypertension, Pulmonary / Q000503:physiopathology* / Q000628:therapy; D007223:Infant; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D010102:Oxygen Inhalation Therapy; D012189:Retrospective Studies; D013815:Thermodilution
Cardiac catheterization; Hyperoxia; Oxygen consumption; Pulmonary hypertension; Pulmonary vasoreactivity; Thermodilution