Can the infusion of isotonic fluids or vasopressors prevent hemodynamic changes in cardiac surgery patients?

A common problem in cardiac surgery patients is decreased central venous pressure (CVP) and systemic blood pressure during transfer from operation room to intensive care unit (ICU). Since these reductions may lead to dangerous complications, this study aimed to evaluate the effects of vasopressors and isotonic fluids on hemodynamic status of cardiac surgery patients during their transfer to ICU. This randomized single-blind clinical trial was conducted in Chamran Hospital (Isfahan, Iran). A total number of 75 consecutive patients undergoing planned first-time coronary artery bypass grafting entered our study. Systolic blood pressure (SBP), diastolic blood pressure (DBP), CVP, and pulse rate (PR) were recorded at 5 to 10 minutes before leaving operating room and immediately after hospitalization in the ICU. Subjects in the first group received 7 cc/kg intravenous normal saline (as an isotonic fluid) within 5-10 minutes. The second group received 10 mg ephedrine before being transferred to the ICU. The mean age of participants was 61.0 ± 3.6 years. No significant change in PR was detected in normal saline group (P > 0.05). No significant differences were found in two groups in SBP before and after hospitalization in the ICU (P > 0.05). DBP and CVP had statistically significant reductions in both groups after hospitalization in the ICU (P < 0.001). The mean CVP was also reduced significantly (10.7 ± 2.9 vs. 8.2 ± 3.4; P < 0.001). Significant reductions in mean values of DBP and CVP occur during cardiac surgery and after arrival to the ICU. These reductions cannot be prevented by administration of vasopressors, such as ephedrine, or infusion of isotonic fluids, such as normal saline. Further studies are required to assess whether more fluids, other types of fluids, or other drugs can stop this phenomenon.