Peripheral tissue oxygenation and the number of organs transplanted per donor.

Current donor management practices target macrohaemodynamic parameters, but it is unclear if this leads to improvements in microvascular perfusion and tissue oxygenation; the latter may have more impact on organ status. In a recent preclinical study we determined that brain death impaired tissue perfusion and oxygen utilisation in swine while pharmacologic correction of these deficits improved organ function and reduced markers of tissue injury. As a first step in translating the preclinical findings, we conducted a prospective observational study to determine if there was an association between peripheral tissue oxygenation (measured by near-infrared spectroscopy) in deceased by neurological criteria human donors and the number of organs transplanted. In 60 donors, the mean time-weighted average of tissue oxygenation was 87.5% (standard deviation, SD, 5.2%) and the average number of organs transplanted was 3.5 (SD 2); there was a positive linear relationship between these two parameters. A 5% rise in tissue oxygenation was associated with an increase of 0.47 organs transplanted (95% confidence intervals 0.16 to 0.78) after adjusting for age (P=0.004). No such correlations were observed for the macrohaemodynamic or macro-oxygenation parameters (including arterial blood oxygenation). The results of this clinical trial are consistent with our preclinical work and support the postulate that targeting the microvasculature to improve tissue perfusion and tissue oxygen delivery in human donors has the potential to increase the quantity of organs suitable for transplant.

The effect of inhalational anaesthesia during deceased donor organ procurement on post-transplantation graft survival.

Many deceased by neurologic criteria donors are administered inhalational agents during organ recovery surgery-a process that is characterised by warm and cold ischaemia followed by warm reperfusion. In certain settings, volatile anaesthetics (VA) are known to precondition organs to protect them from subsequent ischaemia-reperfusion injury. As such, we hypothesised that exposure to VA during organ procurement would improve post-graft survival. Lifebanc (organ procurement organisation [OPO] for NE Ohio) provided the investigators with a list of death by neurologic criteria organ donors cared for at three large tertiary hospitals in Cleveland between 2006 and 2016-details about the surgical recovery phase were extracted from the organ donors' medical records. De-identified data on graft survival were obtained from the United Network for Organ Sharing (UNOS). The collated data underwent comparative analysis based on whether or not VA were administered during procurement surgery. Records from 213 donors were obtained for analysis with 138 exposed and 75 not exposed. Demographics, medical histories, and organ procurement rates were similar between the two cohorts. For the primary endpoint, there were no significant differences observed in either early (30-day) or late (five-year) graft survival rates for kidney, liver, lung, or heart transplants. Our findings from this retrospective review of a relatively small cohort do not support the hypothesis that the use of VA during the surgical procurement phase improves graft survival. Reviews of larger datasets and/or a prospective study may be required to provide a definitive answer.

Recent advances in perioperative anesthetic management update on the role of vasopressin and its effects on outcomes.

The vasoconstrictive and antidiuretic physiologic properties of vasopressin (antidiuretic hormone) have long been known. Until recently however, vasopressin was mostly used for diabetes insipidus and noctournal enuresis. This review summarizes the growing body of evidence regarding the perioperative use of vasopressin and its analogues in the management of certain forms of cardiovascular collapse. Physiologically, vasopressin is involved in regulating osmotic, volemic, and cardiovascular homeostasis. It acts via several specific vasopressin receptors that are variably distributed in the heart, kidneys and vasculature etc. Under normal conditions, its antidiuretic effect predominates and vasopressin only induces vasoconstriction at high concentrations. Regarding catecholamine-resistant vasodilatory shock, current evidence suggests that with adequate volume resuscitation, exogenous vasopressin in low "physiologic" doses (0.01-0.04 units/min) safely supports mean arterial pressure without adversely affecting myocardial function and splanchnic circulation. One possible explanation is that metabolic acidosis impairs the function of alpha-adrenergic (but not vasopressin) receptors, thus diminishing the response to catecholamines. Although there is yet no clear cut mortality benefit, vasopressin is now recommended as a second-line agent in septic shock for its catecholamine-sparing effect and as an alternative to epinephrine in cardiopulmonary resuscitation. It has also demonstrated efficacy in ameliorating vasoplegia after cardiopulmonary bypass as well as perioperative hypotension in patients on renin-angiotensin system antagionists preoperatively. In summary, accumulating clinical experience and formal studies indicate that vasopressin has a role in restoring vascular tone in refractory vasodilatory shock states with minimal adverse effects provided that euvolemia is assured.

Circulating-water garment or the combination of a circulating-water mattress and forced-air cover to maintain core temperature during major upper-abdominal surgery.

BACKGROUND: A recent heat-balance study in volunteers suggested that greater efficacy of circulating-water garments (CWGs) results largely from increased heat transfer across the posterior skin surface since heat transfer across the anterior skin surface was similar with circulating-water and forced-air. We thus tested the hypothesis that the combination of a circulating-water mattress (CWM) and forced-air warming prevents core temperature reduction during major abdominal surgery no worse than a CWG does. METHODS: Fifty adult patients aged between 18 and 85 yr old, undergoing major abdominal surgery, were randomly assigned to intraoperative warming with a combination of forced-air and a CWM or with a CWG (Allon ThermoWrap). Core temperature was measured in the distal oesophagus. Non-inferiority of the CWM to the CWG on change from baseline to median intraoperative temperature was assessed using a one-tailed Student's t-test with an equivalency buffer of -0.5°C. RESULTS: Data analysis was restricted to 16 CWG and 20 CWM patients who completed the protocol. Core temperature increased in both groups during the initial hours of surgery. We had sufficient evidence (P=0.001), to conclude that the combination of a CWM and forced-air warming was non-inferior to a CWG in preventing temperature reduction, with mean (95% CI) difference in the temperature change between the CWM and the CWG groups (CWM-CWG) of 0.46°C (-0.09°C, 1.00°C). CONCLUSIONS: The combination of a CWM and forced-air warming is significantly non-inferior in maintaining intraoperative core temperature than a CWG. TRIAL REGISTRY: This trial has been registered at clinical trials.gov, identifier: NCT 00651898.

Ventricular dysfunction associated with brain trauma is cause for exclusion of young heart donors.

OBJECTIVE: Ventricular dysfunction (VD) in the context of brain death (BD) is one medical cause that may be reversed to extend the range of donors for cardiac transplant programs. The aim of this study was to identify and quantify the causes for exclusion of potential heart donors and to define risk factors for VD among the BD population. MATERIALS AND METHODS: This study of 100 heart-beating potential donors defined subjects as those younger than 50 years. We defined hemodynamic dysfunction (HD) as failure to achieve hemodynamic objectives despite the use of inotropic agents by protocol or upon diagnosing VD. RESULTS: Among 246 BD subjects were 100 potential heart donors. Of these, 75 were transformed into real donors (RD) including 13 heart RD and 62 noncardiac RD. The conversion rate of BD subjects younger than 50 years to heart RD was 17%. When we analyzed the medical reasons for exclusion of the 62 donors who were not converted to heart RD, we observed that HD was the major cause (34%). When we analyzed the causes for exclusion related to cause of death, cranial trauma predominated (52%; P = .01; relative risk 3.5; 95% confidence interval 1.4-8.5). CONCLUSION: Hemodynamic dysfunction represented the major cause for loss of heart donors; it was associated with younger patients with cranial trauma.

International indicators of donation and solid organ transplantation.

The main goal of any organ procurement organization (OPO) is to offer the greatest number of organs achievable with the goal of reducing mortality and the waiting list time of patients. Evaluation of OPO activity is mandatory to identify causes of missed potential donors seeking to implement changes in steps susceptible of improvement. In this review, we have presented the classical indicators of brain death along with new indicators. We observed that when the donor generation capacity is adjusted to the deaths, the indicator is more reliable for comparisons of countries with different mortality rates. We concluded that the indicators are complementary, because they measure different aspects of the process. To have a better understanding of the situation, country, institution, or hospital, one should simultaneously use all of the indicators.

Brain death epidemiology in Uruguay and utilization of the Glasgow coma score in acute brain injured patients as a predictor of brain death.

OBJECTIVE: The knowledge of brain death (BD) epidemiology and the acute brain injury (ABI) progression profile are relevant to improve public health programs, organ procurement strategies, as well as intensive care unit (ICU) protocols aiming to increase the detection of potential donors. The aim of this study was to analyze the BD epidemiology and the ABI progression profile among subjects admitted to ICUs with a Glasgow Coma Score (GCS) < or = 8. MATERIALS AND METHODS: This was a prospective, observational study of BD reported to the National Institute of Donation and Transplantation from 2000-2006. The patients with ABI and GCS < or = 8 who were admitted to 5 ICUs with In-hospital Transplant Coordination were analyzed over the period of 2005-2007. RESULTS: The BD detection increased from 28.7 in 2000 to 58.5 BD pmp in 2006. The real donor global rate increased from 10 to 24.6 pmp from 2000 to 2006. The ABI patients with GCS < or = 8 had a global mortality rate of 56%, including 23.4% who evolved to BD. CONCLUSIONS: This study showed a 200% increment of detected BD and 150% of real donors, although these results are still below the international figures. GCS follow-up appeared to be a good tool to predict the BD outcome. The follow-up of patients with ABI allowed us to improve our BD detection strategy.