The Effect of Postoperative Anemia after Cardiac Operation on Exercise Capacity
| Autor: | Yi-Chi Chiu, 邱羿綺 |
|---|---|
| Rok vydání: | 2013 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 101 Background and purpose: Postoperative anemia becomes a prevalent comorbidity after cardiac surgery with the updated clinical guidelines. The newly onset anemia during hospitalization are reported to be associated with the in-hospital mortality and also with the long-term mortality if anemia sustained at hospital discharge. The exact mechanism remains unclear, but the potential physiological consequences are proposed as reduced myocardial oxygen supply, increased burden of impaired peripheral oxygenation and hemodynamic compromise. This may limit the activity participation, but what level of anemia limit exercise and whether any cautions should be taken care remain unclear. This study aimed to investigate the effect of postoperative anemia on exercise capacity, and to identify which level of hemoglobin may result in a poor exercise capacity. Methods: We studied 259 patients (27% female, 60.2 ± 12.1 years old) who received cardiac surgery and had normal hemoglobin level before operation, from the exercise test database of a heart center in 2011. We collected the hemoglobin data during admission, the walking distance, mean speed and cardiovascular responses at the end of phase I cardiac rehabilitation (CR). Energy expenditure index (EEI) and rate pressure product (RPP) were derived as cardiovascular work efficiency. Peak oxygen consumption as exercise capacity was based on the result of exercise test. Demographic and clinical characteristics were also collected. Results: Among 259 patients with cardiac surgery, the incidence of postoperative anemia was 98.8% and only 6.6 % patients freed from anemia at discharge. Patients with postoperative anemia had significantly slower walking speed before discharge and decreased incrementally with the severity of anemia (mild: 61.9±11.8, moderate: 53.1±9.7, severe: 44.5±10.9 m/min, P < 0.001). The EEI and RPP were significantly higher among patients with more severe anemia. The Hb in 9.05mg/dl was the cutoff to correlate with slow walking speed (69% sensitivity, 71% specificity, AUC = 0.74(95%CI =0.676-0.81)). Peak oxygen consumption was also significantly lower among patients sustained anemia at discharge. The Hb at discharge in 11.25 mg/dl was the cutoff to correlate with poor exercise response (50% sensitivity, 87% specificity, AUC=0.74(95%CI =0.681-0.803)) Conclusions and Clinical Relevance: Extremely high incidence of postoperative anemia and little recovery at discharge could be found among patients after cardiac surgery. Postoperative anemia has a dose-response effect on the exercise function both at admission and after discharge. Caution that greater cardiovascular work and more limitations to exercise are associated with the severity of anemia. Our findings highlight such a growing medical problem may impact the recovery of patients and our clinical practice. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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