The level of hypotension during hemorrhagic shock is a major determinant of the post-resuscitation systemic inflammatory response: an experimental study

<p>Abstract</p> <p>Background</p> <p>To evaluate whether the level of hypotension during hemorrhagic shock may influence the oxidative and inflammatory responses developed during post-ischemic resuscitation.</p> <p>Methods</p> <p>Fifteen rabbits were equally allocated into three groups: sham-operated (group sham); bled within 30 minutes to mean arterial pressure (MAP) of 40 mmHg (group shock-40); bled within 30 minutes to MAP of 30 mmHg (group shock-30). Shock was maintained for 60 min. Resuscitation was performed by reinfusing shed blood with two volumes of Ringer's lactate and blood was sampled for estimation of serum levels aminotransferases, creatinine, TNF-α, IL-1β, IL-6, malondialdehyde (MDA) and total antioxidant status (TAS) and for the determination of oxidative burst of polymorhonuclears (PMNs) and mononuclear cells (MCs).</p> <p>Results</p> <p>Serum AST of group shock-30 was higher than that of group shock-40 at 60 and 120 minutes after start of resuscitation; serum creatinine of group shock-30 was higher than group shock-40 at 120 minutes. Measured cytokines, MDA and cellular oxidative burst of groups, shock-40 and shock-30 were higher than group sham within the first 60 minutes after start of resuscitation. Serum concentrations of IL-1β, IL-6 and TNF-α of group shock-30 were higher than group shock-40 at 120 minutes (p < 0.05). No differences were found between two groups regarding serum MDA and TAS and oxidative burst on PMNs and MCs but both groups were different to group sham.</p> <p>Conclusion</p> <p>The level of hypotension is a major determinant of the severity of hepatic and renal dysfunction and of the inflammatory response arising during post-ischemic hemorrhagic shock resuscitation. These findings deserve further evaluation in the clinical setting.</p

Nitrosative and Oxidative Stresses Contribute to Post-Ischemic Liver Injury Following Severe Hemorrhagic Shock: The Role of Hypoxemic Resuscitation

Purpose: Hemorrhagic shock and resuscitation is frequently associated with liver ischemia-reperfusion injury. The aim of the study was to investigate whether hypoxemic resuscitation attenuates liver injury. Methods: Anesthetized, mechanically ventilated New Zealand white rabbits were exsanguinated to a mean arterial pressure of 30 mmHg for 60 minutes. Resuscitation under normoxemia (Normox-Res group, n = 16, PaO2 = 95–105 mmHg) or hypoxemia (Hypox-Res group, n = 15, PaO 2 = 35–40 mmHg) followed, modifying the FiO 2. Animals not subjected to shock constituted the sham group (n = 11, PaO 2 = 95–105 mmHg). Indices of the inflammatory, oxidative and nitrosative response were measured and histopathological and immunohistochemical studies of the liver were performed. Results: Normox-Res group animals exhibited increased serum alanine aminotransferase, tumor necrosis factor- alpha, interleukin (IL)-1b and IL-6 levels compared with Hypox-Res and sham groups. Reactive oxygen species generation, malondialdehyde formation and myeloperoxidase activity were all elevated in Normox-Res rabbits compared with Hypox-Res and sham groups. Similarly, endothelial NO synthase and inducible NO synthase mRNA expression was up-regulated and nitrotyrosine immunostaining increased in animals resuscitated normoxemically, indicating a more intense nitrosative stress. Hypox-Res animals demonstrated a less prominent histopathologic injury which was similar to sham animals. Conclusions: Hypoxemic resuscitation prevents liver reperfusion injury through attenuation of the inflammatory respons

Effect of percutaneous endoscopic gastrostomy on gastro-esophageal reflux in mechanically-ventilated patients

AIM: To investigate the effect of percutaneous endoscopic gastrostomy (PEG) on gastroesophageal reflux (GER) in mechanically-ventilated patients. METHODS : In a prospective, randomized, controlled study 36 patients with recurrent or persistent ventilator-associated pneumonia (VAP) and GER &gt; 6% were divided into PEG group (n=16) or non-PEG group (n=20). Another 11 ventilated patients without reflux (GER &lt; 3%) served as control group. Esophageal pH-metry was performed by the “pull through” method at baseline, 2 and 7 d after PEG. Patients were strictly followed up for semi-recumbent position and control of gastric nutrient residue. RESULTS: A significant decrease of median (range) reflux was observed in PEG group from 7.8 (6.2 -15.6) at baseline to 2.7 (0 - 10.4) on d 7 post-gastrostomy (P &lt; 0.01), while the reflux increased from 9 (6.2-22) to 10.8 (6.3 - 36.6) (P &lt; 0.01) in non-PEG group. A significant correlation between GER (%) and the stay of nasogastric tube was detected (r=0.56, P&lt; 0.01). CONCLUSION: Gastrostomy when combined with semi-recumbent position and absence of nutrient gastric residue reduces the gastroesophageal reflux in ventilated patients. (C) 2006 The WIG Press. All rights reserved

Hypoxemic resuscitation after hemorrhagic shock is accompanied by reduced serum levels of angiopoietin-2

Background: To investigate whether angiopoietin-2 (Ang2) and vascular endothelial growth factor (VEGF) are implicated in the hypoxemic resuscitation from hemorrhagic shock. Methods: Twenty rabbits were subjected to hemorrhagic shock after blood exsanguination; resuscitation was performed by infusion of the shed blood in ten rabbits under normoxemic conditions (NormoxRes) and in 10 under hypoxemic conditions (HypoxRes); four rabbits were subjected to sham operation. Serum was drawn at serial time intervals: serum was applied for stimulation of U937 monocytes. Results: Serum concentrations of Ang2 were higher in the NormoxRes group compared to the HypoxRes group at 90 min (p: 0.049) and at 120 min (p: 0.028). Serum concentrations of VEGF did not differ between groups. Concentrations of VEGF in the supernatants of U937 stimulated with sera of all groups were below detection limit The wet to dry. lung ratio of the HypoxRes group was significantly lower than the NormoxRes group (p &lt; 0.0001). Conclusions: Hypoxemic resuscitation from hemorrhagic shock is a process accompanied by reduced serum levels of Ang2. These findings add significantly to our understanding of that experimental treatment strategy of resuscitation. (C) 2009 Elsevier Ltd. All rights reserved

Reasons of PEG failure to eliminate gastroesophageal reflux in mechanically ventilated patients

AIM: To investigate factors predicting failure of percutaneous endoscopic gastrostomy (PEG) to eliminate gastroesophageal reflux (GER)