CLINICAL CATHETER FOR CONTINUOUS BLOOD-GAS MEASUREMENT BY MASS-SPECTROMETRY

A new Teflon catheter for continuous in vivo measurement of blood gases by mass spectrometry has an outer diameter of 0.032 inches and can be inserted through percutaneous puncture with an 18-gauge needle. Response time (63% of a total change) is 40 s for O2 and 65 s for CO2. When calibrated in analyzed gas at 37.degree. C, the catheter-mass spectrometer system analyzed tonometered blood with an error of 1.6% for O2 and 1.9% for CO2. Temperature dependence is 2.0% per .degree. C for O2 and 1.6% per .degree. C for CO2. The catheter was thromboresistant during in vivo use in 7 dogs and measurements compared favorably with results of blood sample analyses by standard hospital methods. Compared with previous devices, the new catheter provides size and convenience advantages that make it more applicable for routine clinical use.