Methylene blue attenuates the hemodynamic changes of the ischemia reperfusion syndrome in liver transplantation, and this effect involves guanylate cyclase inhibition.

Aims: We evaluated the possibility that repeated ischemic preconditioning or N-acetylcysteine (NAC) could prevent ischemia-reperfusion injury as determined by indocyanine green plasma disappearance rate (ICG-PDR) or has favorable hemodynamic effects during reperfusion in an in vivo canine liver model. Methods: Under general anesthesia, 3 groups of mongrel dogs (n = 5 per group) were subjected to (1) 60-min hepatic ischemia, (2) same ischemia preceded by intravenous administration of 150 mg kg^–1 NAC, and (3) three episodes of IPC (10-min ischemia followed by 10-min reperfusion) prior to same ischemia. Hepatic reperfusion was maintained for a further 180 min, with hemodynamic and hepatic function parameters monitored throughout. Results: Plasma disappearance rate of indocyanine green and serum levels of aspartate transferase and alanine transferase showed no significant differences between groups. Although liver injury was obvious, reflected by hemodynamic, blood gas, and liver function tests, NAC and IPC failed to prevent decay in hepatic function in this canine model. Conclusion: The results do not support the hypothesis that short-term use of NAC and IPC is beneficial in hepatic surgery.

Repeated ischemic preconditioning might improve hemodynamic parameters, whereas we were unable to find any significant differences between the groups regarding N-acetylcysteine.

INTRODUCTION.Prone position ventilation (PPV) can improve oxygenation in acute respiratory failure (ARF). There is neither an evidence for an obvious improvement of outcome nor proved positive effects on the further course of critical illness so far. The aim of our study is to analyze the effect of PPV on the course of sepsis and acute respiratory failure. METHODS.We studied 110 consecutive patients with an ARF, n=18 with ALI and n=92 with ARDS (mean age 66±13 [SE]) in a clinical follow-up design at a SICU in a university hospital, who met the criteria of the American-European consensus definition. All patients were ventilated intermittent in supine and prone position (135°left/right-side-position) for at least six hours per day for supportive treatment of ARF. Responder or non-responder each after a time interval of 8, 16, 24 or 48h after starting PPV were defined by a higher or lower oxygenation-index respectively in comparison to the median of all patients in each time interval. Data collection included individual oxygenation-index and the cause of death in deceased patients. (Statistical analysis-SPSS®:Mann-Whitney-Test). RESULTS.PPV was well tolerated in all n=110 patients and showed a significant increase of PaO2/FiO2-ratio in n=106 within the first six hours of PPV (SP 149±0,52 vs. PP 230±0,73mmHg [mean±SEM]). In the remaining four cases there was a positive effect within the first 24 hours. N=67 (61%) of the patients died and n=43 (39%) survived ARF. The outcome subsequent to the defined time intervals was different:Death as a result of sepsis (S) or respiratory failure (RF) later on Time interval after 8h after 16h after 24h after 48h Responder (S)