Peripheral arterial blood pressure versus Central Arterial Blood Pressure Monitoring in Critically Ill Patients after Cardio-pulmonary Bypass

Objective: To determine the accuracy of peripheral (radial) arterial access as compared to central (femoral) arterial access for measurement of invasive blood pressure (IBP) in critically ill patients after cardiopulmonary bypass.

Methods: Sixty patients (60) who required high inotropic/vasopressor support on weaning from cardio-pulmonary bypass and weaned off in 2nd attempt were included in this study. The duration of this study was from June 2015 to August 2016. Radial and femoral arterial access was achieved in all patients for simultaneous measurement of blood pressure. Arterial pressures were noted after 5, 15 and 30 minutes of weaning from cardiopulmonary bypass for both radial and femoral artery simultaneously.

Results: Mean age of study patients was 56.48±11.17 years. 85% patients were male. There was significant difference in systolic blood pressure, diastolic blood pressure and mean arterial pressures between the radial artery and femoral artery cannulation. Mean arterial pressures were significantly high in femoral artery as compared to the radial artery. The mean arterial pressures after five minutes of weaning using central access were 76.28±10.21 mmHg versus 64.15±6.76 mmHg in peripheral arterial access (p-value <0.001). Similarly we also found significant difference in mean arterial pressures after 15 minutes of weaning from cardiopulmonary bypass 78.70±10.12 mmHg in central access versus 72.03±6.76 mmHg using peripheral arterial access (p-value <0.001). The difference in arterial pressures were less marked as compared to the previous differences after 30 minutes of weaning from cardiopulmonary bypass as compared to the earlier readings (p-value 0.001).

Conclusion: Peripheral arterial pressures are unreliable in critically ill patients after cardiopulmonary bypass receiving high dose of inotropic drugs. Central arterial access should be used in these patients to get accurate estimates of patients’ blood pressure in early periods after cardiopulmonary bypass.