Deep hypothermic circulatory arrest and the femoral-to-radial arterial pressure gradient

Objectives: To determine the femoral-to-radial arterial pressure gradient, as well as the factors associated with them, in patients receiving cardiopulmonary bypass (CPB) with profound hypothermia and circulatory arrest. Design: Retrospective automated hemodynamic record review. Setting: University hospital. Participants: Patients undergoing pulmonary thromboendarterectomy with deep hypothermic circulatory arrest. Measurements and Main Results: The automated hemodynamic records of 54 consecutive patients undergoing pulmonary thromboendarterectomy with deep hypothermic circulatory arrest were reviewed, comparing the femoral and radial arterial pressures throughout the intraoperative period. In 20 of the patients, the hemodynamic data from the first 16 postoperative hours were also studied. Forty-one of 54 (76%) of the patients exhibited a mean arterial gradient of at least 10 mmHg either during or after CPB, femoral being higher. Clinically significant gradients were noted throughout the CPB period and the post-CPB period in these patients. In the 54 patients studied, the systolic blood pressure (SBP) gradient was 32 ± 19 mmHg after CPB (95% confidence limits 28.2 mmHg, 39.0 mmHg), and the mean arterial pressure (MAP) gradient was 6.3 ± 4.9 mmHg (95% confidence limits 5.5 mmHg, 8.6 mmHg). The duration of clinically significant SBP (>10 mmHg) and MAP (>5 mmHg) gradients in the postoperative period were 5.2 ± 5.7 hours and 5.8 ± 7.2 hours, respectively. Advanced age correlated with high post-CPB pressure gradients in this population and was associated with prolonged postoperative resolution of the gradients. Conclusions: The femoral-to-radial arterial pressure gradients, particularly systolic, after CPB, were greater and of longer duration in these patients undergoing deep hypothermic circulatory arrest than gradients previously reported for routine CPB. Central arterial pressure monitoring is recommended for patients undergoing deep hypothermic circulatory arrest, being valuable both for intraoperative and postoperative care.