Abstract
BACKGROUND:
Most hyperbaric medicine centers do not monitor arterial oxygen (PaO2 ) and carbon dioxide (PaCO2 ) tensions during hyperbaric oxygen, but many can transcutaneously monitor oxygen (PtcO2 ) and carbon dioxide (PtcCO2 ).
METHODS:
We compared PtcO2 and PtcCO2 measurements to simultaneous PaO2 and PaCO2 measurements in 10 healthy volunteers to determine if PtcO2 and PtcCO2 measurements are surrogates for PaO2 and PaCO2 in the hyperbaric environment. We took blood samples via arterial catheter and took PtcO2 and PtcCO2 chest measurements while the subjects were compressed in a monoplace hyperbaric chamber at pressures between 0.85 atmospheres absolute (atm abs) (our local atmospheric pressure, at altitude 1,300 m) and 3.0 atm abs, while the subjects breathed air, then oxygen.
RESULTS:
The PtcO2 correlated with PaO2 (r2 = 0.99). Under all the conditions, the PtcO2 values were lower than PaO2 values by approximately 10%. The PtcCO2 was 2-6 mm Hg higher than the PaCO2 , but the correlation was low (r2 = 0.21).
CONCLUSIONS:
The PtcO2 in normal humans may be used to estimate the PaO2 . The PtcCO2 may not be an adequate reflection of the PaCO2 . It is unknown if PtcO2 and PtcCO2 measurements in critically ill patients can replace PaO2 and PaCO2 measurements.
Keywords
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