Vasopressin vs. Norepinephrine in Post-CABG Patient with Impella Device
Switching from norepinephrine (levophed) to vasopressin is recommended for a post-CABG patient with an Impella device who has low systolic blood pressure and narrow pulse pressure because vasopressin provides more favorable hemodynamic effects by decreasing the pulmonary vascular resistance to systemic vascular resistance (PVR/SVR) ratio while maintaining adequate systemic perfusion pressure. 1
Hemodynamic Considerations with Impella Device
- The Impella device is a temporary mechanical circulatory support device that increases left ventricular afterload, which can negatively impact cardiac recovery in post-CABG patients 2
- Narrow pulse pressure from the right radial arterial line suggests a mixing point proximal to the innominate artery, indicating potential hemodynamic compromise 2
- Low systolic blood pressure in a post-CABG patient with an Impella device indicates the need for vasopressor support to maintain adequate mean arterial pressure (MAP) for cerebral and end-organ perfusion 2, 3
Advantages of Vasopressin over Norepinephrine
- Vasopressin decreases the PVR/SVR ratio (0.10±0.03 to 0.08±0.03) while norepinephrine maintains or increases it (0.09±0.02 to 0.09±0.02), which is particularly beneficial for right ventricular function 1
- Low-dose vasopressin (0.03 IU/min) has been shown to improve cardiac function during separation from cardiopulmonary bypass in patients with mild to moderate left ventricular dysfunction 4
- Vasopressin provides better hemodynamic stability in CABG patients compared to norepinephrine, with less need for beta-blockers to control heart rate 5
Clinical Evidence Supporting Vasopressin Use
- In patients undergoing CABG surgery, vasopressin is more effective than norepinephrine in restoring systemic vascular resistance while simultaneously reducing right heart afterload 1
- Prophylactic low-dose vasopressin infusion prevents post-CPB hypotension in patients who continued ACE inhibitors preoperatively 6
- Vasopressin infusion has been shown to improve cardiac output, cardiac index, stroke volume index, and fractional area of contraction compared to normal saline in post-CABG patients 4
Management Protocol for Vasopressin Administration
- Start vasopressin at 0.03 IU/min as this dose has been shown to be effective in improving hemodynamics in post-CABG patients 4, 6
- Monitor mean arterial pressure targeting 70 mmHg to ensure adequate cerebral and end-organ perfusion while minimizing LV afterload 2, 5
- Assess for improvement in hemodynamic parameters including cardiac output, SVR, and PVR/SVR ratio 1
- Continue to monitor for signs of adequate tissue perfusion including urine output and arterial blood gases 5
Potential Pitfalls and Considerations
- Vasopressin may cause excessive vasoconstriction if used at high doses, so careful titration is necessary 3
- In patients with concomitant right ventricular failure, the combination of milrinone with vasopressin may provide better hemodynamics than milrinone with norepinephrine 1
- Patients with Impella devices require careful anticoagulation management, as there is a higher risk of bleeding complications compared to other support devices 3
By switching from norepinephrine to vasopressin in this post-CABG patient with an Impella device and hemodynamic compromise, you can achieve better systemic perfusion pressure while optimizing the PVR/SVR ratio, ultimately improving cardiac function and tissue perfusion.