Aerospace medicine and biology: A continuing bibliography with indexes (supplement 356)

This bibliography lists 192 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during November 1991. Subject coverage includes: aerospace medicine and psychology, life support systems and controlled environments, safety equipment, exobiology and extraterrestrial life, and flight crew behavior and performance

Long-term Non-invasive Ventilation in Children: Trends, Outcomes and Adherence

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Medicina, Departamento de Pediatría. Fecha de lectura: 13-05-201

Clinical and Preclinical Lung Transplantation in the aspects of improving outcome

Lung transplantation (LTx) is an established therapeutic option for end-stage pulmonary disease. However, it remains restricted by donor lung scarcity. Donor's lungs are rejected frequently due to severe lung damage caused by aspiration or neurogenic pulmonary oedema that can all lead to acute lung injury (ALI), and more severe acute respiratory distress syndrome (ARDS). Lung transplant patients face poor survival rates in comparison with other solid organ transplantations. This is primarily due to a high incidence of postoperative complications, such as primary graft dysfunction (PGD) and chronic lung allograft dysfunction (CLAD), especially bronchiolitis obliterans syndrome (BOS). The aim of this thesis was to expand the availability of a donor's lungs for transplantation. We sought to increase the chances of a lifesaving opportunity for recipients who may otherwise have remained on the transplant waiting list for years. We did this preclinically by utilising a variety of techniques to regain lung function in discarded lungs, thus increasing the donor pool. We investigated the role of cytokine adsorption during ex vivo lung perfusion (EVLP), and extracorporeal haemofiltration post-transplant as a means of treating and restoring the ARDS-damaged lungs and reducing the incidence of PGD post-transplantation. The lungs were evaluated regarding the development of primary graft dysfunction (PGD) in which cytokines seem to be an essential target given the outcome of significantly less PGD in the group receiving cytokine adsorption. We suggest this treatment method will increase the availability of the donor's lungs and increase the tolerability of the donor's lungs in the recipient. The results of this study formed the basis for our idea to investigate the effect of mesenchymal stromal cell (MSC) therapy to restore gastric content aspirations damaged lungs and reduce the incidence of PGD at 72 hours’ post-transplantation. Furthermore, we explored pulmonary function, survival, and the incidence of CLAD between patients receiving marginal lungs after ex vivo lung perfusion (EVLP) reconditioning and patients receiving clinically standard lungs (conventional lungs) at our centre. These patients were followed for over 10 years. We did not find any difference in pulmonary function, survival, or incidence of CLAD, indicating that EVLP is safe to use and does not increase mortality. We also explored the impact of allograft ischaemic time (IT) in lung transplantation survival rate which showed superior outcomes for IT between 120 and 240 minutes. Every 2-hour increase in IT was equivalent to an increased mortality of up to 24% within 5 years. This indicates that IT has a key role in improving LTx outcomes. We explored the role of plasma biomarkers in the largest subgroup of CLAD, patients with BOS. Plasma from lung- transplanted patients with different BOS grades was analysed for protein biomarkers using Olink proteomics. A selective number of biomarkers were then validated using an enzyme-linked immunosorbent assay (ELISA) at baseline and after 1 year. Corticotropin-releasing hormone (CRH) levels were found to be related to different stages of BOS which identified CRH as a potential marker in a novel diagnostic tool to detect BOS. In conclusion, using EVLP is a safe effective platform for cytokine adsorption therapy and MSC therapy which can restore pulmonary function in damaged donor lungs, thus increasing the donor pool. CRH is a novel potential biomarker in the progression of post-transplantation BOS grades

Aerospace Medicine and Biology: A continuing bibliography with indexes supplement 201

This bibliography lists 191 reports, articles, and other documents introduced into the NASA scientific and technical information system in December 1979

End organ effects of paediatric cardiopulmonary bypass

Despite the scientific, technological and surgical improvements of the past 50 years organ dysfunction following elective paediatric cardiac surgery utilising cardiopulmonary bypass continues to account for increased complications, often leading to a protracted course in hospital with a longer stay in intensive care and the potential for irreversible organ damage long term. Furthermore, paediatric cardiac surgeons are routinely undertaking more complex operations with a shift from palliation to early correction. This has resulted in younger children being subjected to longer periods on the bypass machine with increased effects on vital organs. This thesis describes two clinical studies designed to further assess and characterise peri-operative cardiac, renal and pulmonary function in children undergoing elective cardiac repair at a tertiary referral centre in Scotland, UK. In the first instance a prospective, observational study was undertaken in forty-five children to examine the use of tissue Doppler imaging in the assessment of peri-operative cardiac function, its relationship to myocardial injury and clinical outcome. Tissue Doppler parameters were obtained using a Vivid 7 ultrasound scanner with a 7-MHz probe pre-operatively, on admission to paediatric intensive care and on day one. Myocardial injury was assessed using Troponin-I on the first post-operative day by a commercially available chemiluminescent immunoassay. In twenty children within this group peri-operative renal function was also investigated using standard estimates of glomerular filtration rate, namely creatinine clearance measured by the kinetic Jaffe method during the first and second twelve hour post-operative periods, in comparison to serum creatinine and the novel biomarker cystatin C. Routine plasma retained pre-operatively and on days 0, 1, 2 and 3 post-operatively was used to measure serum cystatin C and creatinine using a particle-enhanced nephelometric immunoassay and the Roche Creatinine Plus enzymatic assay respectively. The association between cystatin C and recorded perfusion parameters including bypass duration, pump flow, haematocrit, oxygen delivery and Troponin-I was investigated. Peri-operative pulmonary function was evaluated through a phase IV, randomised, double-blind, placebo controlled trial. In total, twenty four children were randomised to receive oral sildenafil or equivalent volume placebo four times the day before surgery. Blood samples were collected peri-operatively to measure serum cyclic guanosine monophosphate with a commercially available competitive enzyme immunoassay. Haemodynamic data and echocardiography were acquired at two and twenty four hours post-operatively including pulmonary vascular resistance index and bi-ventricular contractility. Post-operative oxygenation was also determined at the same time by oxygen delivery and oxygenation index. In Chapter 2, peri-operative cardiac function as assessed by tissue Doppler imaging was examined. The results of this study demonstrated that pre-operatively, bi-ventricular systolic function in the study group was reduced compared with normal controls, displaying a significant step-wise decrease with increasing complexity of lesion. This picture persisted post-operatively predominantly in the right ventricle and was significantly associated with the extent of myocardial injury. Impaired peri-operative left ventricular function correlated with clinical outcomes. In Chapter 3, peri-operative renal function as assessed by cystatin C and its association with parameters of perfusion was examined. The results of this study demonstrated that in comparison to serum creatinine, cystatin C had a superior correlation with glomerular filtration rate in the early post-operative period. An elevated level of this biomarker was significantly associated with bypass duration, minimum pump flow and post-operative myocardial injury. Haematocrit was not directly linked to renal dysfunction in this study although evidence of a critical dysoxic threshold within the kidney was suggested indirectly through oxygen delivery calculations. In Chapter 4, peri-operative pulmonary function and vascular reactivity in association with the pre-operative administration of oral sildenafil (0.5mg/kg, six hourly) was examined. The results of this trial demonstrated that compared to placebo, pre-operative sildenafil resulted in modest elevations of serum cyclic guanosine monophosphate, limited effects on pulmonary vascular resistance index, significant reductions in peri-operative bi-ventricular contractility, significant reductions in post-operative oxygen delivery and a trend for increasing ventilatory support. In summary, the current thesis has demonstrated that in children undergoing corrective cardiac surgery peri-operative bi-ventricular function can be accurately assessed by tissue Doppler imaging which to date has had limited use in this patient group. With regards to renal function, cystatin C was shown to be a better estimate of glomerular filtration rate and a more sensitive marker of early renal dysfunction in children after surgery. Furthermore, cystatin C identified a transient post-operative renal impairment, the magnitude of which was associated with duration of bypass, pump flow and myocardial injury. In relation to pulmonary function, this research identified that pre-operative administration of oral sildenafil to children undergoing cardiac surgery produced limited effects on pulmonary vascular resistance but was associated with reduced ventricular contractility and post-operative oxygenation raising significant concerns over its routine clinical use

Aerospace Medicine and Biology. A continuing bibliography with indexes

This bibliography lists 244 reports, articles, and other documents introduced into the NASA scientific and technical information system in February 1981. Aerospace medicine and aerobiology topics are included. Listings for physiological factors, astronaut performance, control theory, artificial intelligence, and cybernetics are included