Ventricular assist devices ( LVAD, ECMO)

Ventricular assist devices ( LVAD, ECMO)

Indicated in cardiogenic shock with

· cardiac index <>2

· systolic BP <>

· RAP > 20 mmHg

· urine <>

· SVR > 2100 dyne seconds

Despite maximal pharmacology and IACP support. (Refer to ECMO manual)

Low output vs high output failure

Patients with low output failure show clinical signs of impaired peripheral circulation and vasoconstriction.

· cold, pale, cyanotic extremities

· decreased stroke volume

· narrowed pulse pressure

Patients with high output failure show clinical signs of vasodilatation.

· warm peripheries

· widened pulse pressure

· increased cardiac output (increased oxygen supply to peripheries)

Cardiogenic shock

Causes

· myocardial revascularisation

· complication of AMI

· transient following cardiopulmonary bypass

Manifestation

· hypotension

· tachycardia

· altered mental state

· diuresis <>

· peripheral vascular collapse

Treatment

Treatment is aimed at

· decreasing workload of the heart

· reducing SVR

· decreasing oxygen consumption

· increasing pump efficiency by adjusting left ventricular filling pressure

· pharmacologically increasing contractility

· reversing hypoxemia and metabolic acidosis

· controlling electrolyte disturbances

· mechanically increasing myocardial contractility

· treatment of dysrhythmias

· intra-aortic counterpulsation