Fingertip temperature during cardiopulmonary bypass

Abstract

Temperature changes in the nasopharynx, fingertip, forearm and extracorporeal circuit were continuously monitored, starting 10 min before and up to 16 min into the rewarming period of hypothermic (32°C) cardiopulmonary bypass in 14 patients operated on for coronary artery revascularization. Arterial blood temperature was the first to increase after starting rewarming, followed by the nasopharynx and the fingertip temperatures. Fingertip temperature started to increase abruptly 6.2 (2.02 SD) min after rewarming started. At this point, nasopharyngeal temperature was 34.2°C (1.42 SD) and took a further 8.3 min to reach 37°C. Assuming that increasing fingertip temperature indicates a central thermoregulatory response to warming, we suggest that nasopharyngeal temperature is a poor monitor of brain temperature. We also suggest that fingertip temperature may be used to monitor the point at which cerebral temperature reaches ‘normothermia’. Further body warming, using arterial temperatures ≥39°C, should be avoided because of the danger of brain hyperthermia.

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References

Nathan HJ , Lavalle G. The management of temperature during hypothermic cardiopulmonary bypass: I - Canadian survey . Can J Anaesth 1995; 42: 669-671 .

Grant RT , Bland EF. Observations on arteriovenous anastomoses in human skin and in bird’s foot with special reference to the reaction to cold . Heart 1931; 15: 385-407 .

Coffman JD. Total and nutritional blood flow in the finger . Clin Sci 1972; 42: 243-250 .

Wyss CR , Brengelmann GR , Johnson JM et al. Altered control of skin blood flow at high skin and core temperatures . J Appl Physiol 1975; 38: 839-845 .

Fox RH , Hilton SM. Bradykinin and heat vasodilatation . J Physiol (Lond) 1958; 142: 219-225 .

Rubinstein EH , Sessler DI. Skin-surface temperature gradients correlate with fingertip blood flow in humans . Anesthesiol 1990; 73: 541-545 .

Lopez M , Sessler DI , Walter K , Emerick T , Osaki M. Rate and gender dependence of the sweating, vasoconstriction and shivering thresholds . Anesthesiol 1994; 80: 780-788 .

Todd MM , Warner DS. A comfortable hypothesis reevaluated. Cerebral metabolic depression and brain protection during ischaemia . Anesthesiol 1992; 76: 161-164 .

Wass CT , Lanier WL , Hofer RE et al. Temperature changes >1°C alter functional neurologic outcome and histopathology in a canine model of complete cerebral ischaemia . Anesthesiol 1995; 83: 325-335 .

10.

Clark RE , Brillman J , Davis DA et al. Microemboli during coronary artery bypass grafting: Genesis and effect on outcome . J Thorac Cardiovasc Surg 1995; 109: 249-258 .

11.

Van der Linden J , Casimir-Ahn H. When do cerebral emboli appear during open heart operations? A transcranial doppler study . Ann Thorac Surg 1991; 51: 237-241 .

12.

Croughwell ND , Frasco P , Blumenthal JA et al. Warming during cardiopulmonary bypass is associated with jugular bulb desaturation . Ann Thorac Surg 1992; 53: 827-832 .

13.

Andrews PJD , Colquhoun AD. Detection of cerebral hypoperfusion during cardiopulmonary bypass . Anaesthesia 1994; 49: 949-953 .

14.

Stone JG , Young WL , Smith CR et al. Do standard monitoring sites reflect true brain temperature when profound hypothermia is rapidly induced and reversed . Anesthesiol 1995; 82: 344-351 .

15.

Leslie K , Sessler DI , Bkorksten AR et al. Propofol causes a dose-dependent decrease in the thermoregulatory threshold for vasoconstriction but has little effect on sweating . Anesthesiology 1994; 81: 353-360 .

16.

Kurz A , Go JC , Sessler DI et al. Alfentanyl slightly increases the sweating threshold and markedly reduces the vasoconstriction and shivering thresholds . Anesthesiol 1995; 83: 293-299 .