To the Editor:—

During a recent living-related orthotopic liver transplant, we observed a significant variation between the radial and femoral arterial pressure waveforms immediately after line placement. The right radial arterial pressure was 30 mmHg higher than the right femoral arterial pressure. The radial arterial pressure correlated with the upper extremity noninvasive blood pressure. Arterial cannulation at both sites was uncomplicated, and both transducers were rezeroed and leveled at the same height. The patient had no history of arterio-occlusive disease. Immediately after the surgeons removed 6 l of ascitic fluid, the waveform discrepancy disappeared and both waveforms correlated to within 5 mmHg. We postulate that the ascites created a compartment-like syndrome impeding arterial blood flow to the lower extremities. Once the fluid was evacuated, the arterial pressure returned to normal as evidenced by correlating radial and femoral pressure waveforms. This is another cause to consider when presented with arterial waveform discrepancy in the patient with ascites or a large intraabdominal mass.