Effect of different perfusion flow on carotid artery blood flow during cardiopulmonary bypass

To investigate the effect of cardiopulmonary bypass (CPB) with different perfusion flow on carotid artery blood by using the carotid artery ultrasound.

Forty-five adult patients during Dec. 2014 to Jan. 2015 scheduled for heart valve replacement or ventricular septal defect repair were randomly divided into 3 groups (n=15) according to different perfusion flow during CPB: A Group 1 [(62±2) mL/(kg·min)], a Group 2 [(72±2) mL/(kg·min)], and a Group 3 [(82±2) mL/(kg·min)]. The diameter of the common carotid artery (CCAD), the peak velocity of the common carotid artery (CCAV),the flow of the common carotid artery (CCAF), the diameter of the internal carotid artery (ICAD), the peak velocity of the internal carotid artery (ICAV) and the flow of the internal carotid artery (ICAF) were measured at the responding time points before the anesthesia induction (T1), after the anesthesia induction (T2), 10 min into CPB (T3), 20 min into CPB (T4), 40 min into CPB (T5), 60 min into CPB(T6), 20 min after CPB ending (T7) by doppler ultrasonography, respectively. The hemoglobin (Hb) and lactic acid were compared at the time before CPB(P1),the time when temperature was decreased to the lowest during CPB (P2), the time when temperature was reheated to 35 ℃ (P3), 20 min after CPB was ended (P4), 2 hours after CPB was ended (P5) by α-steady method. The parameters of CPB and hemodynamic parameters at each time point and postoperative condition were recorded.

There was no significant difference in Hb and lactic acid between the three groups (all P>0.05). For intra-group comparison, the Hb concentration at P2-P5 was lower than that at P1 (all P<0.05), and the Hb concentration was the lowest at P2 and P3. The level of lactic acid at P3-P5 was higher than those at P1 (all P<0.05).There were no significant differences in measurement of carotid artery between the left and right sides of the patients at T1 (all P>0.05). There was no significant difference in CCAV and CCAF among the 3 groups (both P>0.05). For intra-group comparison, the CCAV at T2-T6 was significantly lower than that at T1 (P<0.05), and higher at T7 than that at T2-T6 (all P<0.05), but it was still significantly lower than that at T1 (P<0.05). The difference of CCAF between T2-T5 and T1 was significant (all P<0.05). ICAV of G1 was lower than G3 at T3 (P<0.05). ICAV of G1 was lower than G2, and G2 was lower that G3 at T4 (both P<0.05). ICAV of G1 was lower than G2 at T6 (P<0.05). For intra-group comparison, the ICAV at T2 was significantly lower than that at T1 (P<0.05), and that at T3-T6 was significantly lower than that at T1 and T2 (all P<0.05). At T3-T6, ICAF of G1 was lower than that of G3 (all P<0.05). For intra-group comparison, ICAF at T2-T6 was significantly lower than that at T1 (all P<0.05). At T4, perfusion flow was positively correlated with CCAF, ICAV and ICAV (all P<0.05). None of the patients had obvious motor, sensory, or consciousness disturbance, and no neurological complications.There was no significant difference in postoperative hospital stay, postoperative ICU time, and postoperative extubation time among the 3 groups (all P>0.05).

Different perfusion flows of CPB have different effects on carotids hemodynamics.There is correlation between carotids hemodynamics and perfusion flow. Carotid ultrasound examination can be used to evaluate cardiac output.