Simultaneous continuous measurement of pO2, pCO2, pH and temperature in brain tissue and sagittal sinus in a porcine model.
BACKGROUND
The clinical use of brain tissue oxygen measurement in patients with severe head injury is increasing. It is important to compare the findings in brain tissue with cerebrovenous blood oximetry, to obtain normal values and to find out limitations of the method. We evaluated a newly available multisensor probe simultaneously in the brain tissue and in the sagittal sinus in a porcine animal model.


METHODS
We placed the Paratrend 7-probe (BSL, High Wycombe, UK) in the left frontoparietal white matter and measured pO2 (PtiO2), pCO2 (ptiCO2), pH and temperature while simultaneously measuring these parameters (pcvO2, pcvCO2) in the sagittal sinus in 7 pigs under general anaesthesia during oxygen enhancement.


RESULTS
The relation between oxygen increase in brain tissue and in the sagittal sinus showed a coefficient of correlation (CCmean) rmean = 0.96. The quantitative response in brain tissue was much more sensitive than in the sinus. A close correlation between pCO2 in brain tissue and sagittal sinus and the increase of the inspired oxygen was seen: CC ptiCO2 to arterial oxygen pressure (paO2) - rmean = 0.67, CC pcvCO2 to paO2 - rmean = 0.88.


CONCLUSIONS
Measuring partial oxygen pressure in brain tissue is more responsive to physiological variations, and the absolute values are more sensitive than oxygen measurement in the cerebrovenous compartment. This is important for interpreting measured values and introducing new coefficients for patient monitoring.
Department of Anaesthesiology, Martin-Luther-University Halle-Wittenberg, Federal Republic of Germany.
M
M
Menzel
A
A
Rieger
S
S
Roth
J
J
Soukup
C
C
Peuse
C
C
Hennig
P
P
Molnar
I
I
Furka
J
J
Radke
D000136:Acid-Base Equilibrium / Q000502:physiology*; D000818:Animals; D001833:Body Temperature Regulation / Q000502:physiology; D001921:Brain / Q000098:blood supply*; D001924:Brain Concussion / Q000503:physiopathology*; D002245:Carbon Dioxide / Q000097:blood*; D002408:Catheters, Indwelling; D003392:Cranial Sinuses / Q000503:physiopathology; D006801:Humans; D002534:Hypoxia, Brain / Q000175:diagnosis* / Q000503:physiopathology; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption / Q000502:physiology*; D012039:Regional Blood Flow / Q000502:physiology; D012680:Sensitivity and Specificity; D013552:Swine
D002245:Carbon Dioxide; D010100:Oxygen