Info

Donor Selection and Procurement

In addition to the scarcity of donor organs, cardiac transplantation is further limited by a short ischemic time (4-6 hours). While this has been lengthened through numerous experimental studies clinically, extension of the preservation time has not been well tolerated. As a result the management of the donor before procurement is critical, and this is especially true as older donors are being used. With brain death there are often significant changes in the patient's hemodynamics, metabolism, and temperature control. Myocardium may be damaged from

Table 11.3. Current medical urgency status codes for heart allocation

1A Adult—Registrant at least 18 years of age, admitted to listing hospital with at least one of the following: (a) mechanical circulatory support for acute hemodynamic decompensation with VAD 30 days or less, TAH, balloon pump, or ECMO; (b) mechanical circulatory support for more than 30 days with objective medical evidence of significant device-related complications; (c) mechanical ventilation; (d) continuous infusion of a single high-dose intravenous inotrope or multiple intravenous inotropes, in addition to continuous hemodynamic monitoring of left ventricular filling pressures; or (e) meets none of the criteria specified above but admitted to the listing hospital with a life expectancy without a heart transplant of less than seven days.

Pediatric—Registrant less than 18 years of age and meets at least one of the following criteria: (a) requires assistance with a ventilator; (b) requires assistance with a mechanical assist device; (c) requires assistance with a balloon pump; (d) is less than 6 months old with congenital or acquired heart disease exhibiting reactive pulmonary hypertension at greater than 50% of systemic level; (e) requires infusion of high dose or multiple inotropes; or (f) meets none of the criteria specified above but has a life expectancy without a heart transplant of less than 14 days.

1B Adult—A registrant who (a) has a left and/or right ventricular assist device implanted for more than 30 days; or (b) receives continuous infusion of intravenous inotropes.

Pediatric—A registrant who (a) requires infusion of low dose single inotropes, (b) is less than 6 months old and does not meet the criteria for Status 1A, or (c) exhibits growth failure (see OPTN policies for definition).

2 A patient of any age who does not meet the criteria for Status 1A or 1B.

7 Temporarily inactive.

the changes in blood pressure. Electrolyte imbalances may lead to dysrhythmias and myocardial edema. To stabilize the blood pressure, vasoactive drugs are often instituted. Ideally there should be no need for significant inotropic support. Typically the donor can be managed with dopamine or dobutamine. Maintenance of a mean arterial pressure near 80-mm Hg is necessary. Unfortunately, diabetes insipi-dus can also lead to instability, electrolyte imbalance and acid base abnormalities.

Ideally donors should be less than 40 years old. Those in the fourth and fifth decades of life need careful evaluation for coronary artery disease. Echocardiography must be performed on all potential donors. The echocardiogram should demonstrate normal cardiac anatomy, normal valve function, and normal ventricular function.

In patients greater than 50 years of age, cardiac catheterization should be performed to exclude coronary artery disease. If a pulmonary artery catheter has been placed, the CVP should be in the 10-12 mm Hg range, the pulmonary capillary right pressure less than 15 mm Hg and the cardiac index greater than

2.5 l/min/m2. Allocation is based on ABO blood type and body size. Typically an organ from a donor that is within ten percent of the recipient's weight is acceptable.

Procurement of the donor organ is performed via median sternotomy. The pericardium is opened and the heart is suspended in a pericardial cradle. The heart is

0 0

Post a comment