Management of Neuroendocrine Instability During Maintenance of Potential Organ Donors

Abstract

Solid organ transplantation is the treatment of choice for patients with end-stage cardiac, pulmonary or liver disease. This form of surgical treatment has enjoyed increasing success, with better early and late survival for lung, liver and cardiac transplantation, while renal transplantation is both cost effective and improves the quality of life for the recipient receiving dialysis. The main limiting factor for this successful procedure is the shortage of suitable donor organs, resulting in longer waiting list for patients with a substantial risk of mortality before transplantation (Keegan M.T. 2009). The majority of organs come from patients who suffered an acute neurologic injury, such as traumatic brain injury or cerebrovascular accidents, including spontaneous intracerebral bleeding and thrombosis that progresses to brainstem death. Unfortunately, not all brainstem dead patients become potential organ donors and organ are ultimately harvested from only 15-20% of individuals who satisfy organ donor criteria (Mascia et al 2010). Many reasons contribute to the paucity of donor organs, such as the sub-optimal critical care management of potential organ donors, lack of consent, logistical problems and the use of strict donor criteria (Mascia et al 2006). In the present chapter we will discuss neuroendocrine alterations which occur in acute brain injured patients evolving to brain death. Since most of the data available has been collected in acute neurological patients with varying impairment of the conscious state, we will first summarize the pathophysiology, clinical signs, diagnosis and treatment of endocrine abnormalities in severe brain injury patients and then we will focus on the consequences of neuroendocrine alterations in brain dead subjects. These abnormalities contribute to the hemodynamic and metabolic instability of the potential organ donors and may affect organs availability for transplantation. In severe acute brain injury patients evolving to brain death, hypothalamic-pituitary-adrenal insufficiency occurs in 30-50% (Behan et al 2008; Corneli et al 2007) of patients and a high prevalence of neuroendocrine deficiency is present in brain dead patients (Howlett et al 1989; Salim et al 2006). These endocrine alterations lead to metabolic abnormalities and hemodynamic instability with deleterious effects on these potential organ donors (Ullah et al 2006). Adequate organ donor management is therefore mandatory to prevent, reduce or reverse these alterations and to maintain the functional integrity of potentially transplantable organs. Since all donors are treated in intensive care units an optimal clinical management would be an integral component of intensive care medicine education and