Anne Kirstine Hoeyer-Nielsen1,2, Mathias J Holmberg2,3,4, Anne V Grossestreuer2, Tuyen Yankama5, Jean-Pierre Branton2, Michael W Donnino2, Katherine M Berg2,6. 1. Centre for Prehospital and Emergency Research, Department of Clinical Research, Aalborg University, Aalborg, Denmark. 2. Center for Resuscitation Science, Department of Emergency Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts. 3. Research Center for Emergency Medicine, Department of Clinical Medicine, Aarhus University and Aarhus University Hospital, Aarhus, Denmark. 4. Department of Emergency Medicine, Horsens Regional Hospital, Horsens, Denmark. 5. Department of Pharmacy, Beth Israel Deaconess Medical Center, Boston, Massachusetts. 6. Division of Pulmonary, Critical Care and Sleep, Beth Israel Deaconess Medical Center, Boston, Massachusetts.
Abstract
INTRODUCTION: Mitochondrial dysfunction leading to impairment of oxygen extraction, referred to as cytopathic hypoxia, contributes to morbidity in sepsis. Oxygen consumption (VO2) may be a useful measure of the severity of cytopathic hypoxia. We monitored VO2 and carbon dioxide production (VCO2) in septic patients and investigated the association with hospital survival. METHODS: We retrospectively identified adult (≥18 years) septic patients from a larger prospective observational cohort of critically ill patients on mechanical ventilation. A gas-exchange monitor recorded continuous VO2 and VCO2 for up to 48 h. We then tested the association of median VO2, VCO2, respiratory quotient (RQ), and the VO2:lactate ratio with survival. RESULTS: A total of 46 septic patients were included in the analysis, of whom 28 (61%) survived. Overall median VO2 was not associated with survival (3.72 mL/kg/min [IQR: 3.39, 4.92] in survivors and 3.42 mL/kg/min [IQR: 2.97, 5.26] in non-survivors, P = 0.12). The overall median VCO2 and RQ were also not associated with survival. Adjusting for age and the presence of shock did not change these results. The VO2:lactate ratio was associated with survival (adjusted OR 2.17 [95% CI 1.12, 4.22] per unit increase in ratio, P = 0.03). The percent change in median VCO2 was 11.6% [IQR: -8.2, 28.7] in survivors compared with -8.3% [IQR: -18.0, 4.7] in non-survivors (P = 0.03). The percent changes in median VO2 and RQ were not different between groups. CONCLUSION: The VO2:lactate ratio was significantly higher in survivors, while there was no association between median VO2 alone and survival. There was a significant difference in change in VCO2 over time between survivors and non-survivors.
INTRODUCTION: Mitochondrial dysfunction leading to impairment of oxygen extraction, referred to as cytopathic hypoxia, contributes to morbidity in sepsis. Oxygen consumption (VO2) may be a useful measure of the severity of cytopathic hypoxia. We monitored VO2 and carbon dioxide production (VCO2) in septic patients and investigated the association with hospital survival. METHODS: We retrospectively identified adult (≥18 years) septic patients from a larger prospective observational cohort of critically ill patients on mechanical ventilation. A gas-exchange monitor recorded continuous VO2 and VCO2 for up to 48 h. We then tested the association of median VO2, VCO2, respiratory quotient (RQ), and the VO2:lactate ratio with survival. RESULTS: A total of 46 septic patients were included in the analysis, of whom 28 (61%) survived. Overall median VO2 was not associated with survival (3.72 mL/kg/min [IQR: 3.39, 4.92] in survivors and 3.42 mL/kg/min [IQR: 2.97, 5.26] in non-survivors, P = 0.12). The overall median VCO2 and RQ were also not associated with survival. Adjusting for age and the presence of shock did not change these results. The VO2:lactate ratio was associated with survival (adjusted OR 2.17 [95% CI 1.12, 4.22] per unit increase in ratio, P = 0.03). The percent change in median VCO2 was 11.6% [IQR: -8.2, 28.7] in survivors compared with -8.3% [IQR: -18.0, 4.7] in non-survivors (P = 0.03). The percent changes in median VO2 and RQ were not different between groups. CONCLUSION: The VO2:lactate ratio was significantly higher in survivors, while there was no association between median VO2 alone and survival. There was a significant difference in change in VCO2 over time between survivors and non-survivors.