There’s been a big debate re: who should care for LVAD patients… a general anesthesiologist or a cardiac anesthesiologist? See below for pros and cons of each. Ultimately, I think all anesthesiologists should be comfortable caring for these patients as we’ll see more and more LVAD patients undergoing procedures.
- High power, low-pulsatility index and fluctuating pump speed: Consider pump thrombosis or hypotension, vasodilation, initial response to exercise.
- High power with high pulsatility index: Consider fluid overload, normal physiological response to increased demand; myocardial recovery.
- Low power, low pulsatility index, and unchanging speed: Consider hypertension or inflow/outflow obstruction, LV failure, dysrhythmia.
- Low power with normal or high pulsatility index: Consider suction event.
Con: Cardiothoracic Anesthesiologists Are Not Necessary for the Management of Patients With Ventricular Assist Devices Undergoing Noncardiac Surgery. JCVA, February 2017. Volume 31, Issue 1, Pages 382–387.
- Goals of care for LVAD patients undergoing non-cardiac surgery should be directed at maintaining forward flow and adequate perfusion. Three main factors that affect LVAD flow are preload, RV function, and afterload.
- The right ventricle is the primary means of LVAD filling; therefore, maintaining RV function is imperative.
- Marked increases in systemic vascular resistance should be avoided.
- Generally, decreases in pump flow should first be treated with a fluid challenge. Hypovolemia should be avoided and intraoperative losses should be replaced aggressively. Second line treatment should include inotropic support for the right ventricle.
- Low-dose vasopressin (<2.4 U/h) may be the vasopressor of choice due to its minimal effect on pulmonary vascular resistance.
- Standard Advanced Cardiovascular Life Support Guidelines should be followed; however, external chest compressions should be avoided during cardiac arrest.
- Steep Trendelenburg may increase venous return, risking RV strain. Peritoneal insufflation for laparoscopic surgery also increases afterload and has detrimental effects on preload. Insufflation should utilize minimum pressures and be increased in a gradual, step-wise fashion.
- TEE can be extremely valuable in diagnosing the cause of obstruction.
- Higher the RPMs (pump speed)
- More LV compression, smaller LV size
- Less functional MR
- More AI, less AV opening
- Less LVED diameter
- De Novo Aortic Regurgitation Post LVAD
Aortic valve remains closed during systole
Commissural fusion of the aortic valve from disuse
Subsequent degeneration of valve
Turbulent blood backflow from small outflow cannula onto a closed valve
Persistent elevation of aortic root pressure –> aortic root dilation and valve incompetence
Lower LVAD speed (but that may worsen mitral regurgitation)
Aortic valve surgery or percutaneous intervention
- RV Fractional Area Change (RV FAC)
- RVFAC is a rough measure of RV systolic function (4 chamber view)
RVFAC = (RVEDA – RVESA) / RVEDA
Normal RVFAC = 35 – 63%
- Pulsatility Index:
- normally decrease as pump speed is increased
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