Endothelin-1 in exhaled breath condensate of allergic asthma patients with exercise-induced bronchoconstriction

<p>Abstract</p> <p>Background</p> <p>Exercise-induced bronchoconstriction (EIB) is a highly prevalent condition, whose pathophysiology is not well understood. Endothelins are proinflammatory, profibrotic, broncho- and vasoconstrictive peptides which play an important role in the development of airway inflammation and remodeling in asthma. The aim of the study was to evaluate the changes in endothelin-1 levels in exhaled breath condensate following intensive exercise in asthmatic patients.</p> <p>Methods</p> <p>The study was conducted in a group of 19 asthmatic patients (11 with EIB, 8 without EIB) and 7 healthy volunteers. Changes induced by intensive exercise in the concentrations of endothelin-1 (ET-1) in exhaled breath condensate (EBC) during 24 hours after an exercise challenge test were determined. Moreover, the possible correlations of these measurements with the results of other tests commonly associated with asthma and with the changes of airway inflammation after exercise were observed.</p> <p>Results</p> <p>In asthmatic patients with EIB a statistically significant increase in the concentration of ET-1 in EBC collected between 10 minutes and 6 hours after an exercise test was observed. The concentration of ET-1 had returned to its initial level 24 hours after exercise. No effects of the exercise test on changes in the concentrations of ET-1 in EBC in either asthmatic patients without EIB or healthy volunteers were observed. A statistically significant correlation between the maximum increase in ET-1 concentrations in EBC after exercise and either baseline F_ENOand the increase in F_ENOor BHR to histamine 24 hours after exercise in the groups of asthmatics with EIB was revealed.</p> <p>Conclusion</p> <p>The release of ET-1 from bronchial epithelium through the influence of many inflammatory cells essential in asthma and interactions with other cytokines, may play an important role in increase of airway inflammation which was observed after postexercise bronchoconstriction in asthmatic patients.</p

The effects of sedation on gastric emptying and intra-gastric meal distribution in critical illness

The original publication can be found at www.springerlink.comObjectiveTo evaluate the effects of sedation with morphine and midazolam (M&M) versus propofol on gastric emptying in critically ill patients.DesignDescriptive study.SettingMixed medical and surgical intensive care unit.PatientsThirty-six unselected, mechanically ventilated, critically ill patients.InterventionsGastric scintigraphic data were analysed retrospectively according to whether patients were receiving M&M (n=20; 14M, 6F) or propofol (n=16; 7M, 9F). Measurements were performed over 4 h after administration of 100 ml of Ensure, labelled with 20 MBq Tc99m.Measurements and resultsGastric half-emptying time (t1/2) and total and regional (proximal and distal stomach) meal retention (%) were assessed. The median t1/2 of patients receiving M&M (153 (IQR: 72-434) min) was significantly longer than that of patients receiving propofol (58 (34-166) min, p=0.02). Total gastric retention was greater in patients receiving M&M compared to those receiving propofol (por=5% meal retention at 240 min than those treated with propofol (95% (19/20) vs. 56% (9/16); p=0.01). Changes in blood glucose concentrations during the study were similar in the two groups.ConclusionsIn critical illness, patients receiving M&M for sedation are more likely to have slow gastric emptying, and proximal meal retention than those receiving propofol. The apparent beneficial effects of propofol-based sedation need confirmation by a prospective randomised controlled study.Nam Q. Nguyen, Marianne J. Chapman, Robert J. Fraser, Laura K. Bryant, Carly Burgstad, Katrina Ching, Max Bellon and Richard H. Hollowa

The relationship between blood glucose control and intolerance to enteral feeding during critical illness

ObjectiveTo assess the relationship between blood glucose concentrations (BSL) and intolerance to gastric feeding in critically ill patients.DesignProspective, case-controlled study.Patients and participantsTwo-hourly BSL and insulin requirements over the first 10 days after admission were assessed in 95 consecutive feed-intolerant (NG aspirate > 250 ml during feed) critically ill patients and 50 age-matched, feed-tolerant patients who received feeds for at least 3 days. Patients with diabetes mellitus were excluded. A standard insulin protocol was used to maintain BSL at 5.0-7.9 mmol.Measurements and resultsThe peak BSLs were significantly higher before and during enteral feeding in feed-intolerant patients. The mean and trough BSLs were, however, similar between the two groups on admission, 24 h prior to feeding and for the first 4 days of feeding. The variations in BSLs over 24 h before and during enteral feeding were significantly greater in feed-intolerant patients. A BSL greater than 10 mmol/l was more prevalent in patients with feed intolerance during enteral feeding. The time taken to develop feed intolerance was inversely related to the admission BSL (r= -0.40). The amount of insulin administered before and during enteral feeding was similar between the two groups.ConclusionsFeed intolerance in critically ill patients is associated with a greater degree of glycaemic variation, with a greater number of patients with transient hyperglycaemia. These data suggest more intensive insulin therapy may be required to minimize feed intolerance, an issue that warrants further study.Nam Nguyen, Katrina Ching, Robert Fraser, Marianne Chapman and Richard Hollowa