Abstract 279: Cardiac Arrest is Associated With a Global Level Alteration in Oxygen Metabolism: A Clinical Pilot Study

• Published in: Circulation (New York, N.Y.) Vol. 138; no. Suppl_2
• Main Authors: Shinozaki, Koichiro, Saeki, Kota, Zhou, Qiuping, Cassiere, Hugh, Jacobson, Lee, Rolston, Daniel, Falotico, Julianne, Li, Timmy, Olshan, Marc, Levitus, Matthew, Lampe, Joshua W, Becker, Lance B
• Format: Journal Article
• Language: English
• Published: 06.11.2018
• ISSN: 0009-7322; 1524-4539
• DOI: 10.1161/circ.138.suppl_2.279

Abstract only Objective: We recently reported that a global-level metabolic alteration occurs after cardiac arrest (CA) in our high fidelity rodent model. The finding was that dissociation of O 2 consumption (VO 2 ) and carbon dioxide generation (VCO 2 ) resulted in a respiratory quotient (RQ: calculated by dividing VCO 2 by VO 2 ) that fell well outside the normally cited range of 0.7-1.0. We hypothesized that a lowered RQ is similarly found in human CA patients. Methods: The study consisted of three subject groups: 1) healthy volunteer, 2) post-surgical patient (control) and 3) post-CA patient. We measured the VO 2 and VCO 2 of mechanically ventilated subjects using the Douglas bag method. Inspiration and expiration gas samples were collected in two separate bags . and RQ was calculated from CO 2 and O 2 gas concentrations in the samples. The patients and healthy volunteers were ventilated using the same model mechanical ventilator. Alert healthy volunteers bit onto a mouthpiece and the samples were collected, while post-surgical and post-CA patients were unconscious during the measurements. We measured the RQ of healthy volunteers at normal and high fractions of inspired oxygen (FIO 2 ) in order to test the validity of our methods at various inspired O 2 levels. Results: The RQs of the three healthy volunteers were 0.83, 0.92 and 0.85 at an FIO 2 of 0.21 and 0.86, 0.88, and 0.83 at an FIO 2 of 0.90 respectively. The RQs of the two post-surgical patients were 0.92 and 0.88 at an FIO 2 of 0.5. None of the post-surgical patients had any complications following the surgery and all were discharged. The RQ of a post-CA patient measured 2.5 hours after the CA was found to be 0.72 at an FIO 2 of 0.9. The CA patient expired within 24 hours of hospital admission. Conclusions: The same trend between the findings of both our rodent study and the CA patient suggest that resuscitation from CA alters cellular metabolism on a global level. This metabolic alteration in turn causes the dissociation of O 2 consumption and CO 2 generation resulting in a lowered RQ. Our findings warrant a larger clinical study to confirm a lowered RQ in post-CA patients and bench work to elucidate the causative mechanism of this relationship.