Dominik P Guensch1, Kady Fischer2, Nancy Shie2, Julie Lebel2, Matthias G Friedrich2. 1. From the Philippa and Marvin Carsley CMR Centre at the Montreal Heart Institute, Montreal, QC, Canada (D.P.G., K.F., N.S., J.L., M.G.F.); Department of Anesthesiology and Pain Therapy, Bern University Hospital, Inselspital, Bern, Switzerland (D.P.G., K.F.); and Department of Cardiology and Radiology, Université de Montréal, Montreal, QC, Canada (M.G.F.). dominik.guensch@gmail.com. 2. From the Philippa and Marvin Carsley CMR Centre at the Montreal Heart Institute, Montreal, QC, Canada (D.P.G., K.F., N.S., J.L., M.G.F.); Department of Anesthesiology and Pain Therapy, Bern University Hospital, Inselspital, Bern, Switzerland (D.P.G., K.F.); and Department of Cardiology and Radiology, Université de Montréal, Montreal, QC, Canada (M.G.F.).
Abstract
BACKGROUND: Current guidelines limit the use of high oxygen tension after return of spontaneous circulation after cardiac arrest, focusing on neurological outcome and mortality. Little is known about the impact of hyperoxia on the ischemic heart. Oxygen is frequently administered and is generally expected to be beneficial. This study seeks to assess the effects of hyperoxia on myocardia oxygenation in the presence of severe coronary artery stenosis in swine. METHODS AND RESULTS: In 22 healthy pigs, we surgically attached a magnetic resonance compatible flow probe to the left anterior descending coronary artery (LAD). In 11 pigs, a hydraulic occluder was inflated distal to the flow probe. After increasing PaO2 to >300 mm Hg, LAD flow decreased in all animals. In 8 stenosed animals with a mean fractional flow reserve of 0.64±0.02, hyperoxia resulted in a significant decrease of myocardial signal intensity in oxygenation-sensitive cardiovascular magnetic resonance images of the midapical segments of the LAD territory. This was not seen in remote myocardium or in the other 8 healthy animals. The decreased signal intensity was accompanied by a decrease in circumferential strain in the same segments. Furthermore, ejection fraction, cardiac output, and oxygen extraction ratio declined in these animals. Changing PaCO2 levels did not have a significant effect on any of the parameters; however, hypercapnia seemed to nonsignificantly attenuate the hyperoxia-induced changes. CONCLUSIONS: Ventilation-induced hyperoxia may decrease myocardial oxygenation and lead to ischemia in myocardium subject to severe coronary artery stenosis.
BACKGROUND: Current guidelines limit the use of high oxygen tension after return of spontaneous circulation after cardiac arrest, focusing on neurological outcome and mortality. Little is known about the impact of hyperoxia on the ischemic heart. Oxygen is frequently administered and is generally expected to be beneficial. This study seeks to assess the effects of hyperoxia on myocardia oxygenation in the presence of severe coronary artery stenosis in swine. METHODS AND RESULTS: In 22 healthy pigs, we surgically attached a magnetic resonance compatible flow probe to the left anterior descending coronary artery (LAD). In 11 pigs, a hydraulic occluder was inflated distal to the flow probe. After increasing PaO2 to >300 mm Hg, LAD flow decreased in all animals. In 8 stenosed animals with a mean fractional flow reserve of 0.64±0.02, hyperoxia resulted in a significant decrease of myocardial signal intensity in oxygenation-sensitive cardiovascular magnetic resonance images of the midapical segments of the LAD territory. This was not seen in remote myocardium or in the other 8 healthy animals. The decreased signal intensity was accompanied by a decrease in circumferential strain in the same segments. Furthermore, ejection fraction, cardiac output, and oxygen extraction ratio declined in these animals. Changing PaCO2 levels did not have a significant effect on any of the parameters; however, hypercapnia seemed to nonsignificantly attenuate the hyperoxia-induced changes. CONCLUSIONS: Ventilation-induced hyperoxia may decrease myocardial oxygenation and lead to ischemia in myocardium subject to severe coronary artery stenosis.
Authors: Dominik P Guensch; Kady Fischer; Christof Jung; Samuel Hurni; Bernhard M Winkler; Bernd Jung; Andreas P Vogt; Balthasar Eberle Journal: PLoS One Date: 2019-01-16 Impact factor: 3.240
Authors: Bob Smit; Yvo M Smulders; Etto C Eringa; Harry P M M Gelissen; Armand R J Girbes; Harm-Jan S de Grooth; Hans H M Schotman; Peter G Scheffer; Heleen M Oudemans-van Straaten; Angelique M E Spoelstra-de Man Journal: Microcirculation Date: 2018-02 Impact factor: 2.628
Authors: Bob Smit; Yvo M Smulders; Etto C Eringa; Heleen M Oudemans-van Straaten; Armand R J Girbes; Kimberley E Wever; Carlijn R Hooijmans; Angelique M E Spoelstra-de Man Journal: Crit Care Date: 2018-08-04 Impact factor: 9.097