Maximum tolerable warm ischaemia time in transplantation from non-heart-beating-donors

Is donation after circulatory determination of death feasible for pediatric patients in italy?

To determine the potential effect of a donation after cardiac death active program on the number of organ donors in a Italian Pediatric Intensive Care Unit (PICU). We conducted a retrospective study of all deaths in PICU of an academic Children Hospital between 2012 and 2020, tracing the organ donation activity. Patients were categorized as brain deaths, deaths despite maximal resuscitation, and deaths after withdrawal or limitation of life support. Patient demographics, premortem physiology, end-of-life circumstances, and functional warm ischemia time were recorded. Eligible donors after cardiac death were identified by the absence of medical contraindication and functional warm ischemia time <60 minutes. Of 124 deaths that occurred during the study period, 34 met criteria for brain death, 23 were potential donors, and 13 became actual donors. Of the remaining 90 patients that met criteria for cardiac death, 66 died despite maximal resuscitation, 24 died after withdrawal or limitation of care and between them 13 were identified as theoretically eligible DCD donors. Of these, 5 patients had a functional warm ischemia time of <1 hour and were potential candidates for DCD of 10 kidneys and 2 lungs. Even if few children could have been eligible for DCD in the study period, an active program could have been able to increase the number of potential organ donors by 20% in the last eight years at our institution. DCD deserves to be explored in Italy as a new option for children.

Breath-Hold Diving

Breath-hold diving is practiced by recreational divers, seafood divers, military divers, and competitive athletes. It involves highly integrated physiology and extreme responses. This article reviews human breath-hold diving physiology beginning with an historical overview followed by a summary of foundational research and a survey of some contemporary issues. Immersion and cardiovascular adjustments promote a blood shift into the heart and chest vasculature. Autonomic responses include diving bradycardia, peripheral vasoconstriction, and splenic contraction, which help conserve oxygen. Competitive divers use a technique of lung hyperinflation that raises initial volume and airway pressure to facilitate longer apnea times and greater depths. Gas compression at depth leads to sequential alveolar collapse. Airway pressure decreases with depth and becomes negative relative to ambient due to limited chest compliance at low lung volumes, raising the risk of pulmonary injury called "squeeze," characterized by postdive coughing, wheezing, and hemoptysis. Hypoxia and hypercapnia influence the terminal breakpoint beyond which voluntary apnea cannot be sustained. Ascent blackout due to hypoxia is a danger during long breath-holds, and has become common amongst high-level competitors who can suppress their urge to breathe. Decompression sickness due to nitrogen accumulation causing bubble formation can occur after multiple repetitive dives, or after single deep dives during depth record attempts. Humans experience responses similar to those seen in diving mammals, but to a lesser degree. The deepest sled-assisted breath-hold dive was to 214 m. Factors that might determine ultimate human depth capabilities are discussed. © 2018 American Physiological Society. Compr Physiol 8:585-630, 2018.

Tissue conservation for transplantation

Pathophysiological changes that occur during ischemia and subsequent reperfusion cause damage to tissues procured for transplantation and also affect long-term allograft function and survival. The proper preservation of organs before transplantation is a must to limit these injuries as much as possible. For decades, static cold storage has been the gold standard for organ preservation, with mechanical perfusion developing as a promising alternative only recently. The current literature points to the need of developing dedicated preservation protocols for every organ, which in combination with other interventions such as ischemic preconditioning and therapeutic additives offer the possibility of improving organ preservation and extending it to multiple times its current duration. This review strives to present an overview of the current body of knowledge with regard to the preservation of organs and tissues destined for transplantation.

Is There a Particular Ethical Practice and Policy Space in North America for Uncontrolled Kidney Donation after Circulatory Death?

Despite successful transplantation outcomes in Europe, uncontrolled organ donation after circulatory determination of death (uDCDD) has essentially been a non-starter in North America. In this paper, I identify and explore a set of interesting, ethics-related considerations that are of relevance to this organ donation-transplantation practice. The analysis provides a theoretical platform for my development of a proposal for the creation of a particular ethical practice and policy space for kidney uDCDD in the U.S. and Canada that recognizes and aims to effectively address the various, identified challenges and constraints.

A collection of primary tissue cultures of tumors from vacuum packed and cooled surgical specimens: a feasibility study

Primary cultures represent an invaluable tool to set up functional experimental conditions; however, creation of tissue cultures from solid tumors is troublesome and often unproductive. Several features can affect the success rate of primary cultures, including technical issues from pre-analytical procedures employed in surgical theaters and pathology laboratories. We have recently introduced a new method of collection, transfer, and preservation of surgical specimens that requires immediate vacuum sealing of excised specimens at surgical theaters, followed by time-controlled transferring at 4°C to the pathology laboratory. Here we investigate the feasibility and performance of short-term primary cell cultures derived from vacuum packed and cooled (VPAC) preserved tissues. Tissue fragments were sampled from 52 surgical specimens of tumors larger than 2 cm for which surgical and VPAC times (the latter corresponding to cold ischemia time) were recorded. Cell viability was determined by trypan blue dye-exclusion assay and hematoxylin and eosin and immunohistochemical stainings were performed to appreciate morphological and immunophenotypical features of cultured cells. Cell viability showed a range of 84–100% in 44 out of 52 (85%) VPAC preserved tissues. Length of both surgical and VPAC times affected cell viability: the critical surgical time was set around 1 hour and 30 minutes, while cells preserved a good viability when kept for about 24 hours of vacuum at 4°C. Cells were maintained in culture for at least three passages. Immunocytochemistry confirmed the phenotype of distinct populations, that is, expression of cytokeratins in epithelioid cells and of vimentin in spindle cells. Our results suggest that VPAC preserved tissues may represent a reliable source for creation of primary cell cultures and that a careful monitoring of surgical and cold ischemia times fosters a good performance of primary tissue cultures.