Critical Care of the Potential Organ Donor

Abstract

Organ transplantation represents one of the great success stories of 20th century medicine. However, its continued success is greatly limited by the shortage of donor organs. This has led to an increased focus within the critical care community on optimal identification and management of the potential organ donor. The multi-organ donor can represent one of the most complex intensive care patients, with numerous competing physiological priorities. However, appropriate management of the donor not only increases the number of organs that can be successfully donated but has long-term implications for the outcomes of multiple recipients. This review outlines current understandings of the physiological derangements seen in the organ donor and evaluates the available evidence for management strategies designed to optimize donation potential and organ recovery. Finally, emerging management strategies for the potential donor are discussed within the current ethical and legal frameworks permitting donation after both brain and circulatory death.

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“…Hemodynamic instability, the potential for ischemia/reperfusion injury, and concomitant organ failure may result from both the original cause of brain death and the series of events associated with the inflammatory state induced by brain injury. [1][2][3] Donor brain death is a significant risk factor in liver transplant outcomes because marginal liver utilization is associated with higher risk of primary nonfunction of the organ. 4,5 In deceased-donor organ transplant, clinicians attempt life-saving procedures by retrieving organs from deceased donors whose activated inflammatory systems can lead to graft dysfunction.…”

The implications of brain death in donor lung injury: investigation and blockade of the endothelin axis

“…[238,240] Impaired perfusion pressure leads to tissue ischaemia, local inflammation, necrosis and microthrombus formation. [24] Interventions are therefore necessary to support blood pressure and augment tissue perfusion.…”

“…Central to this is recognition that prior management efforts (for example mannitol to manage intracranial hypertension) and development of diabetes insipidus may result in intravascular fluid depletion. [238] Optimisation with fluid therapy is therefore essential. Current literature indicates that crystalloid solutions are preferential to colloid; a systematic review found that hydroxyethyl starch may worsen post-transplant renal function.…”

“…[246] Management of diabetes insipidus promotes haemodynamic stability and reduces fluid administration. [238] Current recommendations are to support blood pressure with a target mean arterial pressure of at least 60 mmHg and urine output of >0.5 mL/kg/hr. [240] …”

“…[76,96,323] In the setting of brain death, the haemodynamic deterioration that occurs after the early catecholamine "storm" often requires vasoactive support to maintain organ and tissue perfusion. [24,238] Thus, nebulisation would allow drug delivery directly to the lung, whilst minimising systemic absorption and possible hypotensive effects. In selecting an endothelin antagonist for the current study, tezosentan fulfils these major criteria (dual receptor antagonism [324] and ability to be nebulised).…”