High Altitude: A Possible Reason for Postoperative Bleeding after Coronary Artery Bypass Graft Operations

Abstract

Background: This study evaluated the possible hypothesis that high altitude might be a reason of excessive postoperative drainage after coronary artery bypass graft operations (CABG). Methods: 212 patients were operated by the same surgical team and included to the study with retrospective data scan on postoperative bleeding after elective CABG with cardiopulmonary bypass (CPB). Study was derived from two different altitude centers: Group A patients (n = 107) from the center at an altitude of 1985 meters and Group B patients (n = 105) from the center in approximately sea level with 150 meters altitude. Multiple preoperative, intraoperative and postoperative characteristics with postoperative bleeding amounts were reviewed and calculated to determine a result through the aim of our study. Results: Preoperative, operative and intraoperative parameters for both groups were almost identical. Statistically significance occurred on intensive care unit treatment period, total hospitalization days, usage of erythrocyte suspension and fresh frozen plasma among postoperative periods on behalf of Group B. Parameters such as CABG numbers, Cross clamp and CPB time were not significant. High altitude patients were considered to be with a higher outcome in preoperative hematocrit (Htc) levels which did not occur in the study group. Htc levels presented a slight elevation for Group A as in the preoperative values but a statistically significance was not calculated. Postoperative bleeding volumes and calculated mean values were statistically significantly different among both groups in days of 1, 2 and 3. Reoperations for hemorrhage occurred in 9 cases (8.4%) in Group A and 4 cases (3.8%) in Group B. Conclusions: We want to attract attention to the relation between high altitude and postoperative bleeding after CABG surgery. But yet uncertain and unidentified physiological and biochemical conditions can be a reason as an uncontrollable perioperative factor in this patients. Operation at high altitude can be a reason for postoperative excessively bleeding.