A review of thyroid hormone administration during adult donor care

Pediatric donor heart utilization variability among organ procurement organizations

BACKGROUND

Organ procurement organizations (OPOs) are responsible for the medical management of organ donors. Given the variability in pediatric donor heart utilization among OPOs, we examined factors that may explain this variability, including differences in donor medical management, organ quality, and candidate factors.

METHODS

The Organ Procurement and Transplant Network database was queried for pediatric (<18 years) heart donors and candidates receiving pediatric donor heart offers from 2010 to 2019. OPOs were stratified by pediatric donor heart utilization rate, and the top and bottom quintiles were compared based on donor management strategies and outcomes. A machine learning algorithm, combining 11 OPO, donor, candidate, and offer variables, was used to determine factors most predictive of whether a heart offer is accepted.

RESULTS

There was no clinically significant difference between the top and bottom quintile OPOs in baseline donor characteristics, distance between donor and listing center, management strategies, or organ quality. Machine learning modeling suggested neither OPO donor management nor cardiac function is the primary driver of whether an organ is accepted. Instead, number of prior donor offer refusals and individual listing center receiving the offer were two of the most predictive variables of organ acceptance.

CONCLUSIONS

OPO clinical practice variation does not seem to account for the discrepancy in pediatric donor heart utilization rates among OPOs. Listing center acceptance practice and prior number of donor refusals seem to be the important drivers of heart utilization and may at least partially account for the variation in OPO heart utilization rates given the regional association between OPOs and listing centers.

Anti-Apoptotic Effects of 3,3',5-Triiodo-L-Thyronine in the Liver of Brain-Dead Rats

Background

Thyroid hormone treatment in brain-dead organ donors has been extensively studied and applied in the clinical setting. However, its clinical applicability remains controversial due to a varying degree of success and a lack of mechanistic understanding about the therapeutic effects of 3,3’,5-Triiodo-L-thyronine (T₃). T₃ pre-conditioning leads to anti-apoptotic and pro-mitotic effects in liver tissue following ischemia/reperfusion injury. Therefore, we aimed to study the effects of T₃ pre-conditioning in the liver of brain-dead rats.

Methods

Brain death (BD) was induced in mechanically ventilated rats by inflation of a Fogarty catheter in the epidural space. T₃ (0.1 mg/kg) or vehicle was administered intraperitoneally 2 h prior to BD induction. After 4 h of BD, serum and liver tissue were collected. RT-qPCR, routine biochemistry, and immunohistochemistry were performed.

Results

Brain-dead animals treated with T₃ had lower plasma levels of AST and ALT, reduced Bax gene expression, and less hepatic cleaved Caspase-3 activation compared to brain-dead animals treated with vehicle. Interestingly, no differences in the expression of inflammatory genes (IL-6, MCP-1, IL-1β) or the presence of pro-mitotic markers (Cyclin-D and Ki-67) were found in brain-dead animals treated with T₃ compared to vehicle-treated animals.

Conclusion

T₃ pre-conditioning leads to beneficial effects in the liver of brain-dead rats as seen by lower cellular injury and reduced apoptosis, and supports the suggested role of T₃ hormone therapy in the management of brain-dead donors.

Controversial points in organ donor management

There are still many controversial aspects regarding which method is best for managing organ donors to prevent, lessen, or even reverse the organ alterations associated with brain death. Fundamental aspects are the management of an adequate perfusion pressure, hormone restoration, and opposition of the inflammatory state associated with brain death. Once volume has been normalized, it is necessary to administer vasoactive drugs, including catecholamines to re-establish the loss of sympathetic tone at the vascular and myocardial level. It is impossible to define the ideal or maximal catecholamine dose because it depends on the donor's vascular tone, vascular reactivity, and pharmacokinetic variability characteristic of critical patients, particularly organ donors. To control early onset of diabetes insipidus, it is necessary to administer desmopressin. At present there are insufficient clinical studies to show the usefulness of triiodothyronine. Furthermore, due to its limited availability, elevated cost, and probable side effects, the use of this hormone is not justified. More importance is being given to the negative influence of the inflammatory state associated with brain death, which has repercussions on organ viability and probably influences the prevalence of rejection episodes. Meanwhile in organ donor management, we recommend the use of 15 mg/kg of methylprednisolone as soon as possible. Contrary to triiodothyronine, the potential benefit of its immunomodulatory effects, its low cost, and the absence of major side effects justify this recommendation.

Neuroendocrine dysfunction in pediatric critical illness

BACKGROUND

The extent of neuroendocrine dysfunction (NED) has not been well defined in critically ill children and likely varies significantly from that in adults. We sought to define the prevalence of neuroendocrine dysfunction in a group of children in a multidisciplinary pediatric intensive care unit and determine the relationship of neuroendocrine dysfunction with severity of illness and presence of sepsis.

METHODS

Prospective observational study in a pediatric intensive care unit at a referral childrens hospital. Blood samples were evaluated within 12 hrs of admission for serum cortisol, thyroid stimulating hormone, total triiodothyronine (T3), reverse triiodothyroine (rT3), free thyroxine, and arginine vasopressin. Pediatric risk of mortality, pediatric logistic organ dysfunction scores, and length of stay were calculated.

RESULTS

Seventy-three children were enrolled over a 13-month period. Median patient age was 72 months (range, 3-228 months). Overall prevalence of absolute adrenal insufficiency ranged from 7% to 58% based on cortisol cutoff chosen. Presence of absolute adrenal insufficiency, low T3 syndrome (LT3S), or vasopressin insufficiency did not differ between septic or nonseptic patients. NED did not correlate with pediatric logistic organ dysfunction, Pediatric Risk of Mortality Score III, length of stay, or mortality. Prevalence of multiple NED was 62% (28 of 45 children), where 62% had 2 neurohormonal deficiencies and 24% had 3 neurohormonal deficiencies.

CONCLUSION

NED is common in both septic and nonseptic critically ill children in a single pediatric intensive care unit. Larger scale studies are necessary to determine whether presence of NED, or specific combinations of neurohormonal dysfunction, is important in predicting outcomes or benefit of early hormonal replacement therapies in critically ill children.

[Organ donation]

For patients with end-stage organ disease transplantation of human organs is a well-established therapy, and in most cases it is the only life-saving one. But the lack of available organs is a big problem. The legal basis in Germany is the transplantation law (TPG). According to this law, every ventilated patient with diagnosed brain death is a potential organ donor. However, brain death may lead to strong reactions in the patient's cardiovascular system as well as disturbances in thermoregulation, water and electrolyte balance, and the endocrine and haemostatic systems. Thus, protecting the organs of the organ donor and, furthermore, caring for his or her relatives are great challenges for every physician and nurse in the intensive care unit.