Oxygen Consumption and Online Blood Gas Determinations during Rewarming on Cardiopulmonary Bypass

Abstract

The online measurement of blood gases during rewarming on hypothermic CPB was performed with sensors utilizing optical fluorescence. In 20 patients, blood samples were obtained at 25°C. 30°C. 34°C and 36°C respectively for determination of oxygen content and calculation of VO₂ to determine the actual changes in VO₂ which occurred and to see if the continuous online measurements of blood oxygen tensions would provide useful information. VO₂ decreased to 31·28 ml/min/m² at 25°C. close to the predicted. With rewarming. VO₂ increased to 36% of predicted at 30°C. and at 36°C. was only 67% of predicted. Online measurement of PvO₂ provided a reasonably accurate reflection of the changing metabolic requirements during this period, more so than PaO₂. These data suggest that the continuous measurement of blood oxygen tensions, particularly PvO₂ provides a simple and effective method of monitoring the adequacy of oxygen delivery.

Get full access to this article

View all access options for this article.

References

Pierce ECII. Extracorporeal circulation for open heart surgery. Springfield: Charles C Thomas, 1969: 7–80.

Parker

Delpy

Halsall

. A new approach to inline gas monitoring: development of an oxygen sensor. Med Biol Eng Comp 1983; 21: 134–37.

Hill

Vinansky

Todd

Groom

Lefrak

. Continuous measurement of oxygen saturation and oxygen tension during cardiopulmonary bypass. Proc Am Acad Cardiovasc Perf 1983; 4: 10–15.

Hill

Vinansky

Todd

Groom

Lefrak

. Continuous measurement of oxygen tension during cardiopulmonary bypass. Proc Am Acad Cardiovasc Perf 1984; 5: 39–42.

Reeder

Hood

. Accuracy of oxygen partial pressure measurements: an in vitro study. J Extracorp Tech 1983; 15: 89–95.

Hickey

Hoar

. Whole body oxygen consumption during low-flow hypothermic cardiopulmonary bypass. J Thorac Cardiovasc Surg 1983; 86: 903–906.

Biro

. The circulation in anaesthesia. In Prys-Roberts ed. Anaemia and haemodilution. Oxford: Blackwell, 1980: 332–33.