Haemorrhagic shock (HS) is commonly associated with trauma. Severe haemorrhage causes hypoperfusion of tissues resulting in a global ischaemic state, and resuscitation is performed to restore circulating volume. However, the return of oxygen to ischaemic tissues causes the induction of a systemic inflammatory response, which contributes to cell death leading to organ failure. In trauma patients, failure of more than four organs is linked to certain mortality, highlighting the need for interventions that may reduce or prevent the deterioration in organ function. The aim of this thesis was to investigate the effect of therapeutic approaches on the organ injury and dysfunction induced by HS. Briefly, male Wistar rats were subjected to haemorrhage by withdrawal of blood to reduce the mean arterial pressure to 35 ± 5 mmHg for 90 min. Followed by resuscitation with 20 ml/kg Ringer’s lactate for 10 min and 50% of the shed blood for 50 min. Organ function was determined 4 h after the onset of resuscitation. This model was used to investigate the effect of three different interventions on the organ injury and dysfunction induced. In the first study, administration of bone marrow-derived mononuclear cells (BMMNCs) upon resuscitation resulted in (1) significant attenuation of the organ injury and dysfunction associated with HS, and (2) restoration of the activation of the Akt pro-survival pathway. It is possible that these beneficial effects are mediated by paracrine mediators secreted by BMMNCs, which modulate this pathway, however injection of large numbers of cells is not practical in the acute setting of trauma. Therefore, in the next study erythropoietin (EPO) was used as a daily pre-treatment for three days prior to the induction of haemorrhage, as EPO is a known stimulus of endothelial progenitor cell (EPC) mobilisation. EPO pre-treatment resulted in (1) significant attenuation of the organ injury and dysfunction associated with HS, (2) mobilisation of EPCs (CD34+/flk-1+), and (3) activation of the Akt pro-survival pathway with enhanced activation of eNOS. However, when used clinically EPO is associated with an increased risk of thrombotic events, therefore in the final study a non-erythropoietic analogue of EPO was investigated. Treatment with pyroglutamate helix B surface peptide (pHBSP) resulted in (1) significant attenuation of the organ injury and dysfunction associated with HS, and (2) activation of the Akt pro-survival pathway with enhanced activation of both eNOS and STAT3. Additionally, late pHBSP treatment, up to 60 min after the onset of resuscitation, exerted the highest degree of protection. The findings of this thesis support the view that modulation of the Akt pro-survival pathway is a potential therapeutic target in the treatment of the ischaemia-reperfusion injury associated with severe haemorrhage and resuscitation.

La traumatologie est la première cause de mortalité chez les sujets de moins de 40 ans dans les pays industrialisés. Le choc hypovolémique lié à une hémorragie du tronc est une cause fréquente de décès, à la fois sur les lieux de l’accident mais également pendant la prise en charge pré-hospitalière et intra-hospitalière. L’existence d’un hémopéritoine est un facteur de sous estimation du traumatisé grave.Le contrôle lésionnel, mieux connu sous les anglicismes « damage control ressucitation » et « damage control surgery », est le paradigme moderne de la prise en charge du choc hémorragique d’origine traumatique. Il comprend une mise en condition minimaliste privilégiant la réalisation d’une hémostase chirurgicale précoce et rapide, suivie d’une réanimation intensive associant transfusion massive, réchauffement et optimisation de la coagulation. Le traitement chirurgical exhaustif des lésions traumatiques est différé au delà de la période d’instabilité.Chez le blessé hémorragique agonique, la thoracotomie de ressuscitation avec clampage de l’aorte thoracique est une pratique courante mais dont les bases factuelles ne sont pas bien établies. En revanche en pathologie artérielle, la voie d’abord endovasculaire a très largement fait preuve de son efficacité.Nous avons émis l’hypothèse qu’un clampage aortique endovasculaire de l’aorte thoracique par voie rétrograde est possible et que cette technique améliore le profil hémodynamique dans le territoire myocardique et cérébral tout en augmentant la survie en cas de choc hémorragique lié à un traumatisme abdominal.Nos résultats suggèrent que cette technique de sauvetage est efficace, même s’il semble exister des limites corrélées à la durée de l’ischémie/reperfusion viscérale et médullaire. / Trauma is the leading cause of mortality in industrialized countries for people aged below 40 years. Fifty percent of the pre hospital and in hospital mortality from severe blunt and penetrating abdominal traumas is due to an hemorrhagic shock. Peritoneal bloody effusion is the main reason to under estimate the seriousness of trauma.Damage control resuscitation (DCR) and damage control surgery (DCS) typify the current paradigm of hemorrhagic torso trauma management. Damage control includes a basic pre operative management before a short surgical control of bleeding followed by intensive resuscitation care based on massive blood transfusion, palliation of hypothermia and correction of biological coagulation disorders. According to this strategy, the curative surgical treatment is postponed until the patient has been stabilized.Some authors have reported on the efficacy of resuscitation thoracotomy with aortic crossclamping in the emergency room in patients with severe abdominal trauma . However, the end results of such a procedure are contrasted and its use is still debated. More recently, endovascular approach has emerged in the management algorithm of some vascular emergencies. We hypothesized that an endovascular retrograde occlusion of the thoracic aorta would be a safe and efficient to preserve hemodynamic profile in cardiac and cerebral area, and to improve survival in case of uncontrolled hemorrhagic shock caused by an abdominal trauma.Our results sustain this hypothesis, even if its benefits seem time-limited, according to the medullar and visceral side-effects of ischemia/reperfusion.

Introduction : Trauma is the leading cause of death in patients between the ages of 1-44 years in South Africa. Taking these statistics into consideration it is essential to better resuscitation strategies in order to improve outcome of trauma patients. Compensated and uncompensated haemorrhagic shock is frequently under diagnosed in trauma patients, which has a definitive effect on mortality. Concerns about inadequate monitoring of patients through the use of only physiological end points are raised. Methods : A comprehensive literature review was conducted on resuscitation strategies for patients presenting with haemorrhagic shock. Physiological and metabolic end points of resuscitation were identified to guide resuscitation strategies. A quantitative, retrospective, non-experimental, descriptive, correlational and crosssectional research design was chosen for this study. Data was collected by using biophysical measures, namely clinical audit checklists. Results : Lactate was identified as a good indicator to predicting mortality in patients presenting with shock caused by haemorrhage. Special consideration to patients’ age and physiological status should be made during resuscitation. The consequence of delayed resuscitation in haemorrhagic shock patients is associated with an increase in mortality that can be prevented. It is found that serum blood lactate levels taken over time are good predictors of patient survival rates. Patients presenting with a raised serum blood lactate level for more than 24-hours has an increase in mortality rate. Conclusion : Emergency nurse practitioners are responsible for the monitoring of patients admitted to the emergency unit with haemorrhagic shock. The use of serum lactate levels during the first 24-hours of the resuscitation of patients with haemorrhage can assist with the implementation of strategies to reverse the effect haemorrhagic shock on cellular level in these patients. / Dissertation (MCur)--University of Pretoria, 2011. / Nursing Science / unrestricted

Les traumatismes graves sont une cause principale d’hospitalisations et peuvent induire des handicaps physiques et psychologiques. Dans ce travail, nous nous intéressons au choc hémorragique (CH), défini par une perte sanguine de plus de 30% menant à une ischémie systémique causant de la mort cellulaire et la libération de médiateurs circulants. Parmi ces médiateurs, notre groupe a déjà démontré l’augmentation en circulation de l’acide urique (AU) après le CH et son rôle dans l’atteinte d’organes ; un effet qui est prévenu par l’utilisation d’une uricase, qui métabolise l’AU circulant. Notre objectif actuel est de démontrer le rôle de l’AU dans l’altération du système nerveux central. Pour ce faire nous utilisons un modèle murin de CH reperfusé avec 3 groupes expérimentaux : SHAM (contrôle), CH et CH+U (uricase IP au moment de la reperfusion). Nos résultats démontrent que l’altération de la perméabilité de la barrière hématoencéphalique (augmentation significative de la perméabilité à la fluorescéine de sodium (NaF)) et de l’expression de ICAM-1 après le CH peut être prévenu par l’administration d’uricase. Les résultats sont les mêmes pour la mesure de la neuroinflammation (activité de la myéloperoxidase (neutrophiles) ainsi que astrocytes et microglie activés) et de l’apoptose/dégérescence neuronale (caspase-3, coloration TUNEL et fluorojade). En conséquence à l’atteinte neuroinflammatoire et apoptotiques, nous observons une augmentation significative des comportements anxieux après le CH, détectés par le test de nage forcée, le labyrinthe en croix surélevé et l’intéraction sociale, et qui sont prévenus par le traitement avec uricase. En conclusion, ce projet permet de confirmer que l’AU joue un rôle important dans l’atteinte cérébrale et l’altération des comportements, après le CH reperfusé. / Polytrauma is one of the main causes of hospitalisations and can lead to physical and psychological handicaps. This work focuses on hemorrhagic shock (HS), defined by a blood-loss of at least 30%, leading to systemic ischemia, cell death and the release of various mediators in circulation. The importance of one of these mediators, uric acid (UA), in multiple organ failure after HS and the improvement by the use of an uricase, which can destroy UA, was already demonstrated by our lab. Our objective is to illustrate the implication of UA in central nervous system alterations after HS. To reach this goal, we use a murine model which is assigned to one of our 3 experimental groups: SHAM (control), HS and HS+U (IP injection of uricase at reperfusion). Our results show an altered blood-brain barrier permeability (significant infiltration of NaF in the brain after HS), an increased expression of ICAM-1 after HS and a prevention of both these results by uricase treatment. The same results are observed for neuroinflammation (myeloperoxidase activity (neutrophils), astrocytes and microglia) and for neuronal apoptosis/degeneration (caspase-3, TUNEL staining and FluoroJade staining). Furthermore, anxiety is increased after HS compared to SHAM but prevented with uricase treatment. The tests used to reach this conclusion are the elevated plus maze, the forced swim test and social interaction. In conclusion, this project confirms the central role of UA in brain lesions and subsequent behavioral alterations after resuscitated HS.