Effects of hydrogen sulfide (H2S) on mesenteric perfusion in experimental induced intestinal ischemia in a porcine model.

INTRODUCTION: Insufficient mesenteric perfusion is a dramatic complication in critically ill patients. Hydrogen sulfide, a newly recognized endogenous gaseous mediator, acts as an intestinal vasoactive agent and seems to protect against mesenteric ischemic damage. We investigated whether sodium hydrogen sulfide, a hydrogen sulfide donor, can improve mesenteric perfusion in an experimental model of pigs, both in physiological and ischemic conditions. METHODS: The study was conducted at Careggi University Hospital (Florence, IT). Fourteen male domestic pigs (≈10 Kg) were anesthetized and mechanically ventilated. Animals were randomized in control and ischemia groups. Mesenteric ischemia was induced with a positive end-expiratory pressure of 15 cmH2O. After mini-laparotomy, each animal received incremental doses of sodium hydrogen sulfide every 20 minutes. Perfusion of both the jejunal mucosa and sternal skin were measured by laser Doppler flowmeter, and systemic hemodynamic parameters were monitored. RESULTS: In the control group, sodium hydrogen sulfide was able to significantly improve the mesenteric perfusion, showing a 50% increase from the baseline blood flow. In the ischemia group, NaHS-induced a two-fold increase of the mesenteric post-ischemic perfusion with a recovery up to 70% of pre- positive end-expiratory pressure mesenteric blood flow. Sodium hydrogen sulfide did not directly or indirectly (by blood flow redistribution) affect the sternal skin microcirculation, heart rates, or mean arterial pressure, suggesting a tissue-specific micro-vascular action. CONCLUSIONS: In a porcine model, we observed a mesenteric perfusion recovery mediated by administration of hydrogen sulfide donor without affecting general hemodynamic.

The use of Modified Early Warning Score may help anesthesists in postoperative level of care selection in emergency abdominal surgery.

BACKGROUND: The Modified Early Warning Score (MEWS) was proposed for early identification of patients deterioration. The purpose of this study was to determine if MEWS calculation can help the anaesthesist select the correct level of care to avoid inappropriate admission to the ICU and to enhance the use of the High Dependency Unit (HDU) after emergency surgical procedures. METHODS: Emergency surgical patients admitted before MEWS application (Jan 2008-Mar 2009) were included in the control group, whereas emergency surgical patients after MEWS introduction constituted the intervention group (Apr 2009-Jan 2010). Admission diagnosis was included into three groups for data analysis: acute abdomen (intestinal occlusion, bowel perforation, intestinal ischemia), non-complicated surgery (hernia recurrence, cholecystitis, appendicitis), and blunt abdominal trauma. In intervention group, MEWS was calculated by the anaesthesists on duty before and after surgical procedure. Patients with a MEWS of 3 or 4 were transferred to the HDU, whereas a MEWS score of 5 or more was considered criteria for ICU admission. RESULTS: A total of 1082 patients were enrolled in this study. The control group was made up of 604 patients, whereas the MEWS group included 478 patients. Baseline and clinical status were comparable between groups. After MEWS introduction, HDU admissions significantly increased from 14% to 21% (P=0.0008), with a significant decrease of ICU admissions (from 11% to 5%; P=0.0010). Mortality rate analysis did not differ between groups. CONCLUSION: This study suggests that the use of a simple and reproducible score system may help in reducing ICU admissions after emergency surgery.

Vitamin D deficiency in septic patients at ICU admission is not a mortality predictor.

BACKGROUND: Vitamin D is involved in immune regulation in humans. Vitamin D serum deficiency is reported to be common in hospitalized patients, especially among Intensive Care Unit (ICU) patients. Our aim was to evaluate the relationship between vitamin D levels in septic patients and outcome. METHODS: A total of 170 patients were studied, of which 92 were severe sepsis/septic shock patients, and 72 were major trauma patients, as an age-matched control group. Exclusion criteria were: age <18 years (y), malnutrition state, pregnancy, breast feeding, chemotherapy, immunotherapy, pathologies affecting bone and calcium metabolism, vitamin D metabolism derangement for therapy, hematological and solid malignancies, and HIV. Vitamin D levels were measured by radioimmunoassay at admission. RESULTS: Median vitamin D levels at admission to ICU were 10.1 ng/mL in the sepsis group and 18.4 ng/mL in the trauma group (P<0.0001). In univariate analysis, mortality rate in septic patients was significantly correlated with age, gender, SAPS II, vitamin D level at admission, duration of mechanical ventilation, and ICU/hospital length of stay, however, the multivariate logistic regression model confirmed significance only for age. CONCLUSION: In our cohort, septic patients showed a significantly lower vitamin D level than trauma patients in comparison to age cohort patients with the same demographic/clinical characteristics, but no clear relationship between vitamin D level and outcome was found. Further studies with larger samples are needed to clarify the prognostic role of vitamin D and nutraceutical interventions in critically ill patients.

Effects of hemoperfusion with an immobilized polymyxin-B fiber column on cytokine plasma levels in patients with abdominal sepsis.

AIM: The beneficial role of hemofiltration with immobilized polymyxin-B fiber (PMX) columns in sepsis, especially sepsis due to gram-negative bacteria, has previously been emphasized. Although the efficacy of PMX-B fiber-mediated hemofiltration in reducing plasma levels of cytokines has been reported, other studies did not confirm this observation. Here we report the effects of PMX-B fiber-mediated hemofiltration on outcome and cytokine plasma levels in patients with abdominal sepsis. METHODS: Twelve consecutive patients admitted to the Intensive Care Unit (October 2006-December 2007) for severe sepsis/septic shock from abdominal infection were treated with standard therapy and 2 cycles of hemofiltration with PMX cartridges. Clinical data and plasma levels of IL-6, IL-10 and TNF-a were measured 24 hours before and after PMX treatment. RESULTS: Plasma concentrations (pg/mL) of IL-6, IL-10 and TNF-a were significantly lower after hemofiltration with a PMX fiber column (279.9+/-69.2 vs. 130.9+/-18.4, 166.4+/-36.7 vs. 45.5+/-12.2, 83.1+/-13.5 vs. 23.9+/-5.1 pg/mL, respectively; P<0.05). After treatment, patients required lower doses of norepinephrine (0.3+/-0.1 vs. 0.8+/-0.1 mg/kg/min) and reduced lactate levels, recovery of respiratory function and improved Simplified Organ Failure Assessment (SOFA) scores. After 28 days, 6 patients (50%) had survived. Subgroup analysis demonstrated that survivors had higher IL-6 and lower IL-10 and TNF-a pre-treatment plasma levels (pg/mL) compared with deceased patients (324.4+/-41.1 vs.235.3+/-38.4; 98.5+/-16.1 vs. 234.3+/-48.6, 44.5+/-9.0 vs.121.6+/-52.3 pg/mL, respectively; P<0.05). No adverse events imputable to the treatment were recorded. CONCLUSION: Hemofiltration with a PMX fiber column was able to reduce plasma levels of IL-6, IL-10 and TNF-a, especially in patients surviving at 28 days. Use of the technique was associated with lower norepinephrine support and an increased PaO2/FiO2 ratio.

Comparison between single-step and balloon dilatational tracheostomy in intensive care unit: a single-centre, randomized controlled study.

BACKGROUND: Balloon dilatational tracheostomy using the Ciaglia Blue Dolphin device has recently been introduced as a modification of the Ciaglia technique. The aim of this study was to compare the new Dolphin system with the single-step dilatational tracheostomy (Ciaglia Blue Rhino) in intensive care unit (ICU) patients. METHODS: Consecutive patients admitted to the ICU of the Emergency Department (Careggi Teaching Hospital, Florence, Italy) from January 2009 to October 2009, aged >18 years and with an indication for percutaneous dilatational tracheostomy (PDT), were enrolled. Exclusion criteria were infection/injury/malignancy of the neck, thyroid gland hypertrophy, severe head injury with uncontrolled intracranial hypertension, and coagulopathy. Patients were randomly assigned to undergo PDT using either the Ciaglia Blue Rhino (n=35) or the Ciaglia Blue Dolphin technique (n=35). Groups were compared according to tracheal puncture, tracheal tube placement time, procedure-related complications, and bleeding. RESULTS: Baseline clinical data were comparable between the two groups. Median procedure time was significantly shorter in the Rhino group compared with the Dolphin group (1.5 vs 4 min, P = 0.035). The presence of limited intra-tracheal bleeding at bronchoscopy examination after 6 h from PDT was more frequent in the Dolphin group than in the Rhino group patients (68.6% vs 34.3%, respectively, P = 0.008). No major bleeding occurred in either group. CONCLUSIONS: PDT using the Ciaglia Blue Dolphin technique is a feasible and viable option in ICU patients, but the Rhino technique had a shorter execution time and seemed to be associated with fewer tracheal injuries.

The value of lung ultrasound monitoring in H1N1 acute respiratory distress syndrome.

We present the case of a healthy young male who developed acute respiratory failure as a result of infection with influenza A/H1N1 of swine-origin and in whom ventilatory support was optimised and recovery of lung function was monitored by the use of sequential chest ultrasound examinations. The potential pivotal role of bedside lung ultrasonography in H1N1-induced respiratory failure is discussed.

Ethanol causes neurogenic vasodilation by TRPV1 activation and CGRP release in the trigeminovascular system of the guinea pig.

Ethanol stimulating transient receptor potential vanilloid 1 (TRPV1) on primary sensory neurons promotes neurogenic inflammation, including calcitonin gene-related peptide (CGRP)-mediated coronary dilation. Alcoholic beverages trigger migraine attacks and activation of trigeminal neurons plays a role in migraine. We have investigated in guinea pigs whether ethanol by TRPV1 stimulation causes neurogenic inflammation in the trigeminovascular system. Ethanol-evoked release of neuropeptides from slices of dura mater was abolished by Ca(2+) removal, capsaicin pretreatment and the TRPV1 antagonist, capsazepine. Intragastric ethanol increased plasma extravasation in dura mater, an effect abolished by capsazepine and the NK1 receptor antagonist, SR140333, and caused vasodilation around the middle meningeal artery, an effect abolished by capsazepine and the CGRP receptor antagonist, BIBN4096BS. Vasodilation of meningeal vessels by TRPV1 activation and CGRP release may be relevant to the mechanism by which alcohol ingestion triggers migraine attacks.

Protective effect of relaxin in cardiac anaphylaxis: involvement of the nitric oxide pathway.

1 Relaxin (RLX) is a multifunctional hormone best known for its role in pregnancy and parturition, that has been also shown to influence coronary perfusion and mast cell activation through the generation of endogenous nitric oxide (NO). In this study we report on the effects of RLX on the biochemical and mechanical changes of ex vivo perfused hearts isolated from ovalbumin-sensitized guinea-pigs induced by challenge with the specific antigen. The possible involvement of NO in the RLX action has been also investigated. 2 A 30-min perfusion with RLX (30 ng ml(-1)) before ovalbumin challenge fully abated the positive chronotropic and inotropic effects evoked by anaphylactic reaction to the antigen. RLX also blunted the short-term coronary constriction following to antigen challenge. Conversely, perfusion with chemically inactivated RLX had no effect. 3 The release of histamine in the perfusate and the accumulation of calcium in heart tissue induced by antigen challenge were significantly decreased by RLX, while the amounts of nitrites in the perfusate were significantly increased, as were NO synthase activity and expression and cGMP levels in heart tissue. 4 These findings indicate that RLX has a protective effect in cardiac anaphylaxis which involves an up-regulation of the NO biosynthetic pathway.