DECLINES IN MIXED VENOUS O2 SATURATION AFTER EXTUBATION ARE RELATED TO INCREASES IN O2 CONSUMPTION

CHEST Journal ◽  
2008 ◽  
Vol 134 (4) ◽  
pp. 164P
Author(s):  
Hazem Ubaissi ◽  
Vinayak Jha ◽  
Guillermo Gutierrez
Keyword(s):  
O2 Consumption ◽  
Venous O2 Saturation ◽  
Mixed Venous

Effect of T4-induced cardiac hypertrophy on O2 supply-consumption balance during normoxia and hypoxia

1984 ◽  
Vol 246 (3) ◽  
pp. H374-H379
Author(s):  
K. Talafih ◽  
G. J. Grover ◽  
H. R. Weiss
Keyword(s):  
Blood Flow ◽  
Myocardial Blood Flow ◽  
Left Ventricular ◽  
Saline Control ◽  
O2 Consumption ◽  
Blood Flows ◽  
O2 Extraction ◽  
New Zealand White Rabbits ◽  
O2 Supply ◽  
Venous O2 Saturation

The purpose of this study was to determine if thyroxine-induced hypertrophic hearts can maintain an adequate O2 supply-consumption balance both at rest and under hypoxic stress. New Zealand White rabbits were given 0.5 mg/kg L-thyroxine (T4) for 3 or 16 days, and a third group served as a control. Chests were opened under anesthesia, and myocardial blood flow was determined using microspheres. In half of these animals, microspectrophotometric determinations were made on left ventricular arterial and venous O2 saturation, and by combining this data with blood flows, O2 consumption was determined. The other animals were then subjected to hypoxia (8% O2 in N2), and flows and O2 consumption were again determined. T4 increased arterial pressure and heart rate in normoxic animals and also increased myocardial blood flow 65 and 210% for 3- and 16-day T4 groups, respectively, with no regional differences. O2 extraction was also increased in T4 animals. O2 consumption increased 134 and 280% in 3- and 16-day T4 groups. Only normoxic saline controls had a regional O2 consumption difference with subendocardial O2 consumption higher than subepicardial values. When compared with their respective normoxic groups, blood flow increased 49 and 101% for the hypoxic 3- and 16-day T4 groups. Hypoxia had no effect on saline control blood flow. Hypoxia decreased O2 extraction 29 and 41%, respectively, in the 3- and 16-day T4 groups and was unchanged in saline controls.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Validation of a respiratory mask for measuring gas exchange in exercising swine

1986 ◽  
Vol 61 (3) ◽  
pp. 1226-1229 ◽  
Author(s):  
M. D. McKirnan ◽  
F. C. White ◽  
B. D. Guth ◽  
J. C. Longhurst ◽  
C. M. Bloor
Keyword(s):  
Regression Analysis ◽  
Gas Exchange ◽  
Linear Regression ◽  
Linear Regression Analysis ◽  
O2 Consumption ◽  
Chronic Exercise ◽  
Fick Principle ◽  
Space Design ◽  
Mask Design ◽  
Mixed Venous

A respiratory mask was developed for resting and exercising swine. The lightweight, low-dead-space design fits airtight against the animals' snouts to provide breath-by-breath measurements of respiration and metabolism. Validation of the mask was carried out using the Fick principle with dye-dilution cardiac outputs and arterial and mixed venous O2 content measurements. Linear regression analysis of O2 consumption (VO2) measurements by the two techniques revealed a slope of 1.07 and a Y-intercept of -1.06 ml X kg-1 X min-1. The standard error of the estimate of VO2 was 3.5 ml X kg-1 X min-1. The mask design permits rapid measurements of ventilation and metabolism in response to acute and chronic exercise.

Effect of stimulation of ansa subclavia on regional myocardial O2 supply and O2 consumption

1983 ◽  
Vol 244 (1) ◽  
pp. H68-H72
Author(s):  
E. Buchweitz ◽  
H. R. Weiss
Keyword(s):  
Blood Flow ◽  
Regional Blood Flow ◽  
O2 Consumption ◽  
Sympathetic Stimulation ◽  
Flow Measurements ◽  
Fick Principle ◽  
O2 Extraction ◽  
O2 Supply ◽  
Venous O2 Saturation ◽  
Stimulation Of

Cardiac sympathetic nerve stimulation produces increases in various indices of cardiac work and metabolism. To determine how these increased O2 demands are met, the effects of stimulation of the ansa subclavia on regional arterial and venous O2 saturation, O2 extraction, blood flow, and O2 consumption were determined in the hearts of 16 pentobarbital-anesthetized open-chest dogs. Microspectrophotometric observations of small regional arteries and veins in quick-frozen hearts to determine regional O2 extraction were combined with regional blood flow measurements with radioactive microspheres to determine regional myocardial O2 consumption by the Fick principle. Ansa subclavia stimulation produced significant increases in maximum rate of pressure development, heart rate, and blood pressure. Under control conditions, venous O2 saturation was lower and O2 extraction higher in the subendocardial compared with the subepicardial region of the left ventricle. While sympathetic stimulation did not alter the mean O2 extraction or venous O2 saturation values, there were no longer significant subepicardial vs. subendocardial differences in these parameters. Flow and O2 consumption in these regions increased proportionally during stimulation. The ratio of O2 supply to O2 consumption was not significantly altered by ansa subclavia stimulation, indicating that sympathetic stimulation produced no adverse effect in either region.

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