Mixed venous O2 saturation: Measured by co-oximetry versus calculated from P $$\bar v$$ o 2

1994 ◽  
Vol 10 (1) ◽  
pp. 39-44 ◽  
Author(s):  
David M. Nierman ◽  
Clyde B. Schechter
Keyword(s):  
Venous O2 Saturation ◽  
Mixed Venous

Central venous O2 saturation and rate of arterial desaturation during obstructive apnea

1989 ◽  
Vol 66 (3) ◽  
pp. 1477-1485 ◽  
Author(s):  
E. C. Fletcher ◽  
R. Kass ◽  
J. I. Thornby ◽  
J. Rosborough ◽  
T. Miller
Keyword(s):  
Cardiac Output ◽  
Continuous Monitoring ◽  
Base Line ◽  
Central Venous ◽  
Cuffed Endotracheal Tube ◽  
The Mean ◽  
Arterial O2 Saturation ◽  
Spontaneously Breathing ◽  
Venous O2 Saturation ◽  
Mixed Venous

We examined the rate of fall of arterial O2 saturation (dSao2/dt) after apnea onset in four spontaneously breathing adult male baboons. We postulated that a lower mixed venous O2 saturation (Svo2) would steepen dSao2/dt by more rapid depletion of alveolar O2. Single isolated (NREP) and five or more sequential repetitive apneas (REP) were created by clamping an indwelling cuffed endotracheal tube at end expiration. Fiberoptic catheters were used for continuous monitoring of Sao2, Svo2, and cardiac output. The mean dSao2/dt for all duration NREP apneas was 0.60%/s. Mean dSao2/dt increased above base line for each consecutive REP apnea and was higher in 60 s than in 45 and 30 s REP apnea series. The increase in dSao2/dt corresponded closely with the fall in preapneic Svo2. Preapneic arterial O2 content fell during successive REP apneas but the maximal decrement from base line (1.3 ml/dl) was much less than the maximal decrement in preapneic mixed venous O2 content of 5.1 ml/dl. Preapneic cardiac output for NREP apneas and nadir cardiac output for REP apneas remained constant. Nadir cardiac output for NREP apneas showed higher values for longer duration apneas. We concluded that dSao2/dt is inversely related to preapneic Svo2.

scholarly journals Role of Pv-aCO2 gradient and Pv-aCO2/Ca-vO2 ratio during Cardiac Surgery

2020 ◽  
Author(s):  
Juan Pablo Bouchacourt ◽  
Francisco Javier Hurtado ◽  
Eduardo Kohn ◽  
Laura Illescas ◽  
Arnaldo Dubin ◽  
...  
Keyword(s):  
Cardiac Surgery ◽  
Venous Blood ◽  
Time Interval ◽  
Anesthesia Induction ◽  
Central Venous ◽  
Co2 Partial Pressure ◽  
Tissue Hypoperfusion ◽  
Multilevel Linear Regression ◽  
Venous O2 Saturation ◽  
Mixed Venous

Abstract Background. Arterial lactate, mixed venous O2 saturation and parameters derived from CO2 metabolism as the venous minus arterial CO2 partial pressure (Pv-aCO2) gradient and the ratio between this gradient and the arterial minus venous oxygen content (Pv-aCO2/Ca-vO2) were proposed as markers of tissue hypoperfusion and oxygenation. The main goals were to characterize their physiologic determinants of Pv-aCO2 difference, and the Pv-aCO2 /Ca-vO2 ratio and the interchangeability of the variables calculated from mixed and central venous samples. Methods. We made a sub-analysis of 35 cardiac surgery patients included in a previous investigation database. Parameters were measured or calculated: after anesthesia induction (T1), end of cardiac surgery (T2), and at 6-8 hours intervals after ICU admission (T3 and T4). Results. Macrohemodynamics was characterized by increased cardiac index and low systemic vascular resistances, after surgery (p<0.05). Hemoglobin, arterial pH, lactate, and systemic O2 metabolism showed significant but transient changes during the study (p<0.05). Pv-aCO2 remained high and without changes along the study, and Pv-aCO2/Ca-vO2 was also high and only decreased at T4 (p<0.05). A weak but significant correlation was observed both, globally and at each time interval, between Pv-aCO2 or Pv-aCO2/Ca-vO2 with factors that may affect the CO2 hemoglobin dissociation. Using a similar approach, a multilevel linear regression model with Pv-aCO2 and Pv-aCO2/Ca-vO2 as outcome variables showed a significant association for Pv-aCO2 with mixed venous O2 saturation (SvO2), and base excess (BE) (p<0.05), while Pv-aCO2/Ca-vO2 was significantly associated with Hb, SvO2 , and BE (p<0.05) but not with cardiac output. Measurements and calculations from mixed and central venous blood were not interchangeable. Conclusions. Since Pv-aCO2 and Pv-aCO2/Ca-vO2 could be influenced by different factors that affect the CO2 dissociation curve, these variables should be considered with caution during the hemodynamic management of cardiac surgery patients. Finally, central venous and mixed values were not interchangeable.

scholarly journals Central and Mixed Venous O2 Saturation

2020 ◽  
Vol 48 (1) ◽  
pp. 2-10
Author(s):  
Guillermo Gutierrez ◽  
Keyword(s):  
Venous O2 Saturation ◽  
Mixed Venous
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