A 64-year-old man with a history of coronary artery disease and severe ischemic cardiomyopathy is brought to the hospital by his wife, who found him at home confused and lethargic. He has a durable continuous flow left ventricular assist device (LVAD) that was surgically implanted 1 year ago as destination therapy for his end stage heart failure. On arrival he is arousable but somnolent. His blood pressure is unable to be obtained with a manual cuff; however, a reading obtained with a Doppler ultrasound is 54 mm Hg. His heart rate is 119 beats per minute, respirations are 26 per minute, and his temperature is 38.0°C. On examination, his jugular venous pressure is 5 mm Hg, his cardiac examination reveals a continuous hum, his peripheral pulses are not palpable, and his extremities are warm without significant edema. Interrogation of his LVAD shows high flow with normal power.
Which of the following would NOT be an appropriate intervention in the acute management of this patient?
A. Placement of an arterial lineCorrect Answer: D
This patient is presenting with clinical features consistent with sepsis and should be treated with aggressive early intervention based on surviving sepsis guidelines, including fluid resuscitation, blood cultures, broad-spectrum antibiotics, and vasopressor therapy to maintain a mean arterial pressure of 70 to 80 mm Hg. An arterial line is necessary in this patient, to monitor blood pressure, because a noninvasive blood pressure device might not pick up blood pressure in the absence of pulsatile flow. Dobutamine is an inodilator that would likely worsen this patient’s hypotension.
A rapid clinical assessment of patients with continuous flow LVADs can be challenging, as it is often not possible to obtain a reliable noninvasive blood pressure measurement, as these patients often do not have palpable peripheral pulses or audible heart sounds. Doppler ultrasonography can be used to obtain a single blood pressure reading; in patients with pulsatility, this more accurately approximates the systolic blood pressure, but in patients with no pulsatility Doppler measurements more closely approximate the mean arterial pressure. However an arterial line should be placed for continuous blood pressure monitoring in unstable patients. Checking the LVAD monitor for flow, power and pulsatility index can also be useful in elucidating the etiology of a patient’s hypotension. In hypotensive patients with low flow, the differential diagnosis includes hypovolemia (hemorrhage, overdiuresis), ventricular arrhythmias, RV dysfunction, cardiac tamponade, and improper pump settings. Sepsis should be suspected in hypotensive patients with high flow and normal power, whereas high power and low flow could indicate pump thrombosis.
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