Ultrasound-guided femoral and popliteal sciatic nerve blocks for below knee surgery in patients with severe cardiac disease.

Abstract

Patients with dilated cardiomyopathy or acute myocardial infarction are at risk of anesthesia complications, and peripheral nerve blocks (PNBs) provide more stable operative hemodynamics than general anesthesia or central neuraxial blocks. We present two rare cases of patients with dilated cardiomyopathy or acute myocardial infarction and a coagulation abnormality that were administered ultrasound-guided femoral and popliteal sciatic nerve blocks as anesthesia for lower limb surgery. A 71-year-old woman (155 cm, 44 kg, ASA 4) was scheduled to undergo open reduction and internal fixation due to a left lateral malleolus fracture. Five year previously, she underwent cardioversion and atrial ablation due to atrial fibrillation and ventricular tachycardia, and was being medicated for liver cirrhosis and dilated cardiomyopathy. Preoperative 2-dimensional electrocardiography showed atrial fibrillation and a left ventricular ejection fraction of 20–25%. Her pulmonary arterial pressure was 30 mmHg. Clopidogrel (75 mg) was maintained during the perioperative period to prevent a thromboembolic event. Prothrombin time international normalized ratio (PT INR) was 1.36, prothrombin time (%) was 64%, and aPTT was 36.6 sec. Ultrasound-guided femoral and popliteal sciatic nerve blocks were chosen due to the risks posed by general anesthesia and a central neuraxial blockade. For the femoral nerve blockade, the patient was placed in the supine position and a linear 6–13 MHz probe (SonoSite M-Turbo ® , SonoSite Bothell, WA, USA) was positioned at left inguinal crease level. Subsequently, after penetrating the fascia iliaca, a 22-gauge 50 mm insulated needle was inserted using the in-plane approach near the femoral nerve (Fig. 1A). After obtaining quadriceps femoris muscle contrac