Effect of nicardipine combined with esmolol on systemic and tissue oxygenation during off-pump coronary artery bypass grafting surgery.
BACKGROUND
The hemodynamics and oxygenation severely fluctuated during the off-pump coronary artery bypass grafting (OPCABG). This study aimed at investigating whether or not nicardipine combined with esmolol (1:10) can maintain systemic and tissue oxygenation during OPCABG.


METHODS
Twenty patients scheduled for OPCABG were divided ramdomly into Group nicardipine (N) and Group nitroglycerine (X) respectively combined with esmolol (E) (Dosage ratio: 1 to 10) (Group N + E and Group X + E) with 10 patients in each group. The mixed solution of N + E or X + E were titrated to maintain mean arterial blood pressure between 70 and 80 mmHg following anesthesia induction. The variables of hemodynamics, arterial blood lactate content (Lac) and gastric intramucosal partial pressure of carbon dioxide were measured at the following time points: after induction of anesthesia (T1), pre-revascularization (T2), grafting of left anterior descending (T3), right coronary descending (T4) and left coronary circumflexus branches (T5), post-revascularization (T6), the end of operation (T7). The delivery of oxygen (DO2), consumption of oxygen (VO2) and gastric intramucosal pH (pHi) were calculated.


RESULTS
The cardiac index (CI) in Group N + E was significantly increased (P < 0.05) as compared with T1 during OPCABG, while it was mildly decreased in Group X + E. The stroke volumes at T4, T5 in Group N + E and at T3-T6 in Group X + E were significantly decreased (P < 0.05). The systemic vascular resistance indices in Group N + E were significantly decreased as compared with T1 (P < 0.05). The heart rates in these two Groups were significantly elevated intraoperatively (P < 0.05). The DO2 after the infusion of N + E was significantly increased (P < 0.05) or leveled to T1, and the Lac were within the normal range. But the DO2 in Group X + E was decreased throughout the procedure, reaching significant level at T5 (P < 0.05), and the Lac was significantly increased beyond normal range (P < 0.05). The pHi in Group N + E was maintained above 7.35 during OPCABG, while it was less than 7.35 from T4 to T7 in Group X + E.


CONCLUSIONS
Nicardipine combined with esmolol (1:10) regimen may maintain systemic and tissue oxygenation during OPCABG.
Wang
Tian-long
TL
Department of Anesthesia, Peking University People's Hospital, Beijing 100044, China. w_tl5595@hotmail.com
Jiang
Yan
Y
Yang
Ba-xian
BX
D001794:Blood Pressure / Q000187:drug effects; D001026:Coronary Artery Bypass; D004359:Drug Therapy, Combination; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008875:Middle Aged; D009529:Nicardipine / Q000008:administration & dosage*; D010100:Oxygen / Q000378:metabolism*; D011412:Propanolamines / Q000008:administration & dosage*
D011412:Propanolamines; D009529:Nicardipine; C036604:esmolol; D010100:Oxygen