Document Detail

Effect of hemorrhagic shock and reperfusion on the respiratory quotient in swine.
MedLine Citation:
PMID:  7874908     Owner:  NLM     Status:  MEDLINE    
OBJECTIVES: Respiratory quotient, the ratio of CO2 production to oxygen consumption (VO2), is principally affected by the fuel source used for aerobic metabolism. Since the respiratory quotient, VO2, and CO2 production cannot be directly measured easily, indirect calorimetry is commonly used to determine the value of these variables at the airway level (i.e., airway respiratory quotient, airway VO2, and airway CO2 production). However, under nonsteady-state conditions, a variety of phenomena can alter the relationship between true metabolic activity and measurements determined by indirect calorimetry. During exercise, for example, airway respiratory quotient increases as anaerobic threshold is reached because of the disproportionate increase in airway CO2 production that results from the CO2 liberated through the buffering of excess hydrogen ions by bicarbonate. We hypothesized that hemorrhage and reinfusion might change airway respiratory quotient in a consistent manner as shock is produced and reversed. DESIGN: Prospective laboratory study. SETTING: University animal laboratory. SUBJECTS: Eight pigs (25 +/- 2 [SD] kg), anesthetized with fentanyl and relaxed with pancuronium bromide, and mechanically ventilated on room air. INTERVENTIONS: The animals were sequentially hemorrhaged and then autotransfused while metabolic and hemodynamic measurements were obtained, using continuous indirect calorimetry and continuous applications of the Fick principle. Hemoglobin, arterial lactate concentration, and blood gases for calibration were measured serially. Analysis of variance was used to compare various periods in time. MEASUREMENTS AND MAIN RESULTS: Between baseline and peak hemorrhage, and between peak hemorrhage and postreinfusion, all of the following variables changed significantly (p < .05): airway VO2 (baseline 6.4 +/- 0.9 mL/min/kg, peak hemorrhage 3.9 +/- 0.6 mL/min/kg, postreinfusion 7.0 +/- 1.4 mL/min/kg); airway CO2 production (baseline 5.5 +/- 0.9 mL/min/kg, peak hemorrhage 4.5 +/- 0.9 mL/min/kg, postreinfusion 6.0 +/- 1.4 mL/min/kg); airway respiratory quotient (baseline 0.87 +/- 0.07, peak hemorrhage 1.16 +/- 0.07, postreinfusion 0.87 +/- 0.05); lactate concentration (baseline 2.4 +/- 1.2 mmol/L, peak hemorrhage 6.7 +/- 1.9 mmol/L, postreinfusion 5.1 +/- 2.0 mmol/L); and delta PCO2 (venous PCO2-PaCO2) (baseline 4.5 +/- 3.6 torr [0.6 +/- 0.5 kPa], peak hemorrhage 12.1 +/- 5.3 torr [1.6 +/- 0.7 kPa], postreinfusion 2.7 +/- 2.7 torr [0.4 +/- 0.4 kPa]). CONCLUSIONS: Airway respiratory quotient increases in hemorrhagic shock and decreases again as shock is reversed during reinfusion. This phenomenon appears related to the buffering of excess of hydrogen ion during hemorrhagic shock.
I L Cohen; F M Sheikh; R J Perkins; P J Feustel; E D Foster
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Critical care medicine     Volume:  23     ISSN:  0090-3493     ISO Abbreviation:  Crit. Care Med.     Publication Date:  1995 Mar 
Date Detail:
Created Date:  1995-04-06     Completed Date:  1995-04-06     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0355501     Medline TA:  Crit Care Med     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  545-52     Citation Subset:  AIM; IM    
Department of Surgery, State University of New York at Buffalo.
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MeSH Terms
Blood Gas Analysis
Carbon Dioxide / metabolism*
Hemoglobins / analysis
Lactates / blood
Oxygen Consumption*
Prospective Studies
Respiration / physiology
Shock, Hemorrhagic / physiopathology*
Reg. No./Substance:
0/Hemoglobins; 0/Lactates; 124-38-9/Carbon Dioxide

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