The Use of Stroke Volume Index to Guide Fluid Therapy during Aortic Surgery with Total Circulatory Arrest, HESHAM Y. HAMODA, HOSSAM S. EL-ASHMAWI, DINA SOLIMAN and MOHAMED BAKRY
Abstract
Background: Instability in hemodynamics is frequently encountered after cardiac surgery with cardiopulmonary bypass, and might be caused by myocardial dysfunction, vasodilatation, and/or hypovolemia. An adequate assessment of ventricular preload and myocardial responsiveness to fluid loading is needed to optimize cardiac output and to avoid pulmonary edema.
Stroke Volume Index (SVI) during mechanical ventilation has been shown to predict the hemodynamic effects of volume expansion in patients with septic shock and cardiac surgery.
Aim of the Study: The aim of this study is to investigate the usefulness of SVI to predict fluid responsiveness and to guide fluid therapy in patients undergoing aortic surgery with total circulatory arrest.
Methods: This study was done on 34 adult patients at the Cardio Thoracic Surgery OR, Kasr Al-Ainy Hospital, Faculty of Medicine, Cairo University, undergoing surgery on the ascending thoracic aorta with or without aortic valve replace-ment or repair, and requiring hypothermic CPB with total circulatory arrest where SVI and CI were determined by transoesophageal echocardiography after weaning from the CPB as a baseline reading then after administration of 500cc ringer then another one after 15 minutes. An increase in Stroke Volume Index (SVI) >_10% is required to be considered a responder.
Results: We found that from the total of 34 patients, only 8 patients were considered responders. After administration of 500cc ringer, SVI and CI were significantly higher in responders than the non-responders.
Conclusion: SVI was a reliable predictor of fluid respon-siveness in less than 25% of patients undergoing aortic surgery with total circulatory arrest while most of the rest of the patients showed unexpected results in that matter so further investigations and researches should be done to make sure about reliability of SVI to guide fluid therapy in these patients.