Combined Femoral and Sciatic Blocks Versus Epidural Anesthesia in Infrainguinal Surgeries, Hemodynamic Stability and Myocardial Morbidity

Background: Infrainguinal surgeries for patients with peripheral vascular disease are often risky due to the nature of the surgical procedure, the associated co-morbidities (diabetes mellitus, hypertension and ischemic heart disease), and the need for efficient post-operative analgesia. Infrainguinal procedures included femoral, popliteal and infra-popliteal vascular bypass surgeries, thrombectomies, embolectomies and endarterectomies. Lower limb amputations (due to more critical ischemia or failed bypass) as well as varicose veins may be added. Using a combination of a sciatic nerve block with a femoral nerve block in these patients is a good anesthetic technique in contrary to the conventional neuraxial (spinal or epidural) anesthesia, which may be a contraindication in anticoagulated patients, septic shock and cardiovascular compromise; again spinal/epidural anesthesia usually causes evident hypotension.Aim of Work: Assessment of significance of hypotension and associated cardiac morbidity in both anesthetic techniques in this critical group of patients.Patients and Methods: We prospectively randomized 80 patients, undergoing unilateral infrainguinal surgeries, to receive either single shot combined femoral and sciatic nerve blocks or lumbar epidural anesthesia. Combined femoral sciatic block group (n=40) received isobaric bupivacaine 0.375% (femoral 20ml and sciatic 20ml) with nerve stimulator guidance. While epidural group (n=40) received isobaric bupivacaine 0.375% using loss of resistance to air technique for space detection then 5-mL aliquots were given to attain a sensory level at T10 which is adequate for surgery. Pre-operative set of cardiac biomarkers (CK, CK-MB and LDH) and ECG was obtained, intra-operative blood pressure, heart rate, dysrhythmias and any chest pain or dyspnea were observed. Post operatively, patients were observed for complications and need for ICU admission, and another set of cardiac biomarkers and ECG were repeated 24 hours later.Results: Significant blood pressure stability was observed in femoral-sciatic group, heart rate showed no difference. A significant smaller drop in cardiac biomarkers was found in epidural group (when compared with femoral-sciatic group) but with no clinical symptoms or ECG changes. Only one case of ST segment depression with no clinical impact was found.Conclusion: The use of combined femoral-sciatic nerve block is superior in hemodynamic stability to conventional epidural analgesia in patients undergoing unilateral Infrainguinal surgeries. However, cardiac morbidity was clinically the same, and with no difference in the incidence of complications.