Changes in tissue oxygen tension, venous saturation, and Fick‐based assessments of cardiac output during hyperoxia

• Published in: Acta anaesthesiologica Scandinavica 2019-01, Vol.63 (1), p.93-100
• Main Authors: Perry, Dorothy A., Thomson, Lindsay M., Pigula, Frank A., Polizzotti, Brian D., DiNardo, James A., Nedder, Arthur, Gauvreau, Kimberlee, Kheir, John N.
• Format: Article
• Language: English
• Subjects: Animals; Aorta; Assessments; Brain; Carbon dioxide; Carbon monoxide; Cardiac output; Cardiac Output - physiology; Fick principle; Heart; Hyperoxia; Hyperoxia - blood; Hyperoxia - physiopathology; Instrumentation; Livestock; Mercury; Myocardium; Oximetry; Oxygen; Oxygen - blood; Oxygen Consumption; Oxygen tension; Oxyhemoglobin; Saturation; Swine; Tension; tissue oxygen tension; Tissues; Veins
• ISSN: 0001-5172; 1399-6576
• DOI: 10.1111/aas.13225

Background Hyperoxemia (arterial oxygen tension >100 mm Hg) may occur in critically ill patients and have effects on mixed venous saturation (SvO2) and on Fick‐based estimates of cardiac output (CO). We investigated the effect of hyperoxemia on SvO2 and on assessments of CO using the Fick equation. Methods Yorkshire swine (n = 14) were anesthetized, intubated, and paralyzed for instrumentation. SvO2 (co‐oximetry) and tissue oxygen tension (tPO2, implantable electrodes) in brain and myocardium were measured during systematic manipulation of arterial oxygen tension (PaO2) using graded hyperoxia (fraction of inspired oxygen 0.21 → 0.8). Secondarily, oxygen‐ and carbon dioxide‐based estimates of CO (FickO2 and FickCO2, respectively) were compared with measurements from a flow probe placed on the aortic root. Results Independent of changes in measured oxygen delivery, cerebral and myocardial tPO2 increased in proportion to PaO2, as did SvO2 (P