Spontaneous oscillations of systemic arterial pressure during cardiopulmonary bypass in man

Abstract

Extracorporeal blood circulation (ECC) provides a steady flow and minimal pulmonary circulation in the absence of cardiac function. Oscillations of systemic arterial pressure were observed in 70 patients during ECC. At the onset of oscillations the frequency was as a rule 4 cycles per minute but depended on the temperature and showed a positive correlation with it. Correspondingly, the amplitude was about 6 mm Hg and depended on aortic pressure and showed a positive correlation with it. During the cooling phase of ECC the frequency decreased and the amplitude increased. The oscillations were independent of central venous pressure and ventilation. The oscillations disappeared either at the beginning of restitution of cardiac function or with decreasing arterial pressure caused by drug administration or rewarming. Arterial blood pressure oscillations have been described in experimental animals under various conditions but also in conscious man. The mechanisms underlying these oscillations are suggested to be nervous in origin, as is possible also in the present findings.

Spontaneous oscillation of systemic arterial pressure during cardiopulmonary bypass in the dog

“…The occurrence of the oscillation in human operations is stochastic (17), although rather common under high-dose fentanyl anesthesia (19). The situation is similar also in animal experiments (1) even though special arrangements are employed (13).…”

“…These waves have also been observed in conscious man (3,4) and especially during cardiopulmonary bypass (6,17,19,22). To our knowledge, oscillation of the systemic arterial pressure during extracorporeal circulation in experimental animals has not been described earlier.…”

Less peri- and postoperative inotropic support in open-heart patients with vasomotor waves during cardiopulmonary bypass?

“…The characteristics of VMW during CPB have been described earlier (17). A typical sample in one patient is seen in Fig.…”

“…The smaller amount of women among oscillating patients, although significant, may be a chance due to the significantly greater proportion of men having coronary operations in our area. In the prior materials of our clinics the proportion of women among patients with VMW has been 12-21% (17,18). The random occurrence of VMW has been a puzzle both in animal experiments (10) as well as in human studies (15,17).…”

“…Spontaneous regular slow oscillation of the systemic arterial pressure during cardiopulmonary bypass (CPB) is a recognized phenomenon in man (3,15,(17)(18)(19). These vasomotor waves (VMW) (Mayer waves, third order waves) have also been observed in conscious man (2,14), and they have been the object of numerous many-faeeted studies in experimental animals (7).…”