1.
Zoerner, Frank, 1973-
(author)
Novel Interventions in Cardiac Arrest : Targeted Temperature Management, Methylene Blue, S-PBN, Amiodarone, Milrinone and Esmolol, Endothelin and Nitric Oxide In Porcine Resuscitation Models
2015
Doctoral thesis (other academic/artistic) abstract
It is a major clinical problem that survival rates after out-of-hospital cardiac arrest have not markedly improved during the last decades, despite extensive research and the introduction of new interventions. However, recent studies have demonstrated promising treatments such as targeted temperature management (TTM) and methylene blue (MB).In our first study, we investigated the effect of MB administered during experi-mental cardiopulmonary resuscitation (CPR) in the setting of postponed hypother-mia in piglets. We set out to study if MB could compensate for a delay to establish targeted TTM. The study demonstrated that MB more than compensated for 30 min delay in induction of TTM. The effect of MB added to that of TTM.The second study examined the effects of TTM and S-PBN on the endothelin system and nitric oxide synthases (NOS) after prolonged CA in a porcine CPR mod-el. The study was designed to understand the cardioprotective mechanism of S-PBN and TTM by their influence on the endothelin system and NOS regulation. We veri-fied for the first time, that these two cardioprotective postresuscitative interventions activate endothelin-1 and its receptors concomitantly with eNOS and nNOS in the myocardium. We concluded that nitric oxide and endothelin pathways are implicated in the postresuscitative cardioprotective effects of TTM.The third study compared survival and hemodynamic effects of low-dose amio-darone and vasopressin to vasopressin in a porcine hypovolemic CA model. The study was designed to evaluate whether resuscitation with amiodarone and vasopressin compared to vasopressin alone would have an impact on resuscitation success, survival, and hemodynamic parameters after hemorrhagic CA. We found that combined resuscitation with amiodarone and vasopressin after hemorrhagic circulatory arrest resulted in greater 3-hour survival, better preserved hemodynamic parameters and smaller myocardial injury compared to resuscitation with vasopressin only.In our fourth study we planned to compare hemodynamic parameters between the treatment group (milrinone, esmolol and vasopressin; MEV) and control group (vasopressin only) during resuscitation from prolonged cardiac arrest in piglets. The study was designed to demonstrate if MEV treatment improved hemodynamics or cardiac damage compared to controls. We demonstrated that MEV treatment reduced cardiac injury compared with vasopressin alone.
2.
Bergquist, Maria
(author)
Glucocorticoid receptors in severe inflammation : Experimental and clinical studies
2014
Doctoral thesis (other academic/artistic) abstract
Septic shock is one of the most common causes of mortality in intensive care, in spite of antibiotic treatment. Glucocorticoid treatment can be used to blunt an overwhelming immune response in severe inflammation. The varying effects of glucocorticoid treatment in sepsis are poorly understood, with consequences for the clinical guidelines for treatment. Glucocorticoids are potent anti-inflammatory mediators which exert their effects through the glucocorticoid receptor (GR). Deeper understanding about the mechanisms of GR signalling may help to guide and improve glucocorticoid treatment. The aim of this thesis was to analyse GR expression and binding capacity in experimental and human septic shock and severe inflammation with cellular specificity using flow cytometry. In the late phase of a murine sepsis model, we observed decreased GR expression in leukocytes. In a murine model of early endotoxic shock, we observed decreased GR binding capacity in spite of an increased expression, in neutrophils. Glucocorticoid treatment was beneficial only when administered early in both models. Compared to healthy subjects, GR expression was increased in leukocytes from patients during the initial sepsis phase, while GR binding capacity was only increased in lymphocytes and monocytes. In contrast, neutrophils and other leukocyte subsets displayed decreased GR binding capacity. Neutrophil numbers were increased in all patients with sepsis compared to healthy subjects. We also studied patients with burn injury after admission before any infectious event had likely occurred, and on day 7 post admission, when several of the patients had been diagnosed with sepsis. GR expression and binding capacity was increased in leukocytes on admission as compared to healthy subjects, and patients diagnosed with sepsis on day 7 had a further increased GR expression in T lymphocytes. GR binding capacity was decreased in proportion to the extent of the burn injury on day 14 post admission. In conclusion, sepsis and severe inflammation have significant impact on the expression and function of GR, likely to influence the efficiency of glucocorticoid treatment. In addition, glucocorticoid treatment is beneficial only when given early in these models of experimental sepsis.
