Status asthmaticus requiring extracorporeal membrane oxygenation associated with rhinovirus infection.

Objective: Evolving research links human rhinovirus (HRV) with status asthmaticus (SA) as well as severe respiratory illness in patients with atopy and asthma. This case series reviews five episodes of HRV-associated SA that required extracorporeal membrane oxygenation (ECMO). Methods: Charts of four patients, five total episodes of ECMO, with SA secondary to HRV were reviewed in this IRB-approved case series. Outcomes included demographic information, past medical history, clinical parameters and spirometry. Results: Patients (three male, one female), mean age 9 years (range 7-12 years) at the time of admission, were African American, on Medicaid, carried a diagnosis of persistent asthma, and had documented non-adherence to prescribed, daily controller medications. One patient had passive smoke exposure. All patients had a mean IgE of 734 (range 12-2497) with seasonal allergic rhinitis was diagnosed in three patients. Cases occurred in spring (3/5) and fall (2/5). Venous/venous ECMO (4/5) or venous/arterial ECMO (1/5) was continued for a mean duration of 4.2 days (range 3-7 days). Spirometry after hospitalization had a mean FEV1 of 1.59 L (81% predicted, range 69%-91%), and an FEF25%-75% 1.13 L (47.5% predicted, range 41%-65%) at an average of 16.7 weeks post ECMO. Conclusions: This case series highlights the association between persistent, poorly controlled asthma and severe SA with HRV infection resulting in ECMO. Despite life-threatening illness, these patients did not demonstrate significant large-airway obstruction following infection. However, patients showed persistently abnormal small airway function, which could be a risk factor or early evidence of vulnerability to infection.

Procalcitonin Levels in Critically Ill Children With Status Asthmaticus.

BACKGROUND: Children with status asthmaticus (SA) often present with fever and are evaluated with chest radiographs (CXRs). In the absence of a confirmatory test for bacterial infection, antibiotics are started whenever there are radiological infiltrates or if there is a suspicion of pneumonia. We undertook this study to determine if serum procalcitonin (PCT) levels at admission are altered in critically ill children with SA. We also sought to determine if serum PCT levels are elevated in children with radiological infiltrates or in children who were treated with antibiotics. METHODS: This is a prospective single-center observational study evaluating serum PCT levels in critically ill children with SA. Study subjects included children 1 to 21 years old, admitted to a pediatric intensive care unit (PICU) with SA between March 2012 and April 2013. For the purposes of this study, patients whose CXRs were read by the radiologist as probable bacterial pneumonia was defined as having "radiological bacterial pneumonia," whereas patients who received antibiotics by the treating physician were defined as having "clinician-diagnosed pneumonia." RESULTS: Sixty-one patients with a median age of 7.3 years (interquartile range, 4-10 years) were included in the study. Fifty-one percent were male. Average Pediatric Risk of Mortality III score was 2.7 (SD, 2.9). Three patients (5%) were determined to have radiological bacterial pneumonia, whereas 52 (85%) did not. Six patients (10%) were indeterminate. The mean PCT level for all patients was 0.65 (SD, 1.54) ng/mL, whereas the median PCT level was 0.3 ng/mL. There was no significant difference in the mean PCT levels between the patients with and without clinician-diagnosed pneumonia (0.33 [SD, 0.36] vs 0.69 [SD, 1.67], P = 0.44). Using a PCT cutoff level of 0.5 ng/mL, a significant association was found with the presence of fever (P = 0.004), but no significant association was found with the presence of CXR infiltrates, radiological bacterial pneumonia, hospital length of stay, PICU length of stay, Pediatric Risk of Mortality III scores, or receipt of antibiotics. CONCLUSIONS: Serum PCT level was not elevated to greater than 0.5 ng/mL in 75% of this cohort of critically ill children with SA admitted to PICU. Presence of CXR infiltrates was not associated with higher PCT levels. Large clinical trials are needed to study the diagnostic and predictive role of PCT in this patient population.

ASTHMA CONTROL STATUS AND LUNG FUNCTION IN RELATION TO VITAMIN D LEVEL IN CHILDREN WITH BRONCHIAL ASTHMA.

The aim of the study - low circulating vitamin D level maybe related to poor asthma control status and decreased lung function. The aim of our research is to establish correlation between serum vitamin D level, asthma control status and lung function. The study was performed in children aged 6-15 years old, including patients with asthma (n=50), who referred to Sachkhere medical center for a visit. The status of asthma control in the basic group was classified as controlled (n=31) and uncontrolled (n=19). The children underwent serum vitamin D and IgE level, spirometry and skin prick tests for the study. Using the multivariate logistic regression analysis, the presence of asthma was associated with the reduced level of vitamin D (OR = 1.35, 95% CI (1,14-1.58) P = 0.011; χ2=6.78; F-0.022) in children with uncontrolled bronchial asthma. 48% of the patients in the group- controlled asthma (n=15) had vitamin D deficit, and in 52% of the cases (n=16) was confirmed with vitamin D insufficient. In the group -uncontrolled asthma - 5% of the patients (n=1) had Vitamin D insufficiency in blood serum. In 95% (n=18) of the patients vitamin D level was significantly low <20 ng/ml. According the results, decreased pulmonary function (p-0.039; χ2-3.12) is strongly associated with low level of vitamin D; but neither serum IgE level (p-0.54; χ2-10.9), nor skin prick test result on dust mite (p-0.50, χ2-5.12 ) was correlations with serum vitamin D low level. The presence of vitamin D deficiency effectively predict increased risk of uncontrolled bronchial asthma in children. Serum vitamin D level is related to lung function too. Therefore, the normalization of the serum levels of Vitamin D may have beneficial effect on improvement of asthma control in the complex of asthma management and preventive measures.

Extracorporeal membrane oxygenation support for life-threatening acute severe status asthmaticus.

INTRODUCTION: Status asthmaticus is a life-threatening condition characterized by progressive respiratory failure due to asthma that is unresponsive to standard therapeutic measures. We used extracorporeal membrane oxygenation (ECMO) to treat patients with near-fatal status asthamticus who did not respond to aggressive medical therapies and mechanical ventilation under controlled permissive hypercapnia. MATERIALS AND METHODS: Between January 2011 and October 2015, we treated 16 adult patients with status asthmaticus (8 women, 8 men, mean age: 50.5±10.6years) with veno-venous ECMO (13 patients) or veno-arterial (3 patients). Patients failed to respond to conventional therapies despite receiving the most aggressive therapies, including maximal medical treatments, mechanical ventilation under controlled permissive hypercapnia and general anesthetics. RESULTS: Mean time spent on ECMO was 300±11.8 hours (range 36-384 hours). PaO2, PaCO2 and pH showed significant improvement promptly after ECMO initiation p=0.014, 0.001 and <0.001, respectively, and such values remained significantly improved after ECMO, p=0.004 and 0.001 and <0.001, respectively. The mean time of ventilation after decannulation until extubation was 175±145.66 hours and the median time to intensive care unit discharge after decannulation was 234±110.30 hours. All 16 patients survived without neurological sequelae. CONCLUSIONS: ECMO could provide adjunctive pulmonary support for intubated asthmatic patients who remain severely acidotic and hypercarbic despite aggressive conventional therapy. ECMO should be considered as an early treatment in patients with status asthmaticus whose gas exchange cannot be satisfactorily maintained by conventional therapy for providing adequate gas change and preventing lung injury from the ventilation.

Diastolic hypotension is an unrecognized risk factor for ß-agonist-associated myocardial injury in children with asthma.

OBJECTIVES: Tachycardia and diastolic hypotension have been associated with ß-2 agonist use. In the setting of ß-agonist-induced chronotropy and inotropy, diastolic hypotension may limit myocardial blood flow. We hypothesized that diastolic hypotension is associated with ß-agonist use and that diastolic hypotension and tachycardia are associated with biochemical evidence of myocardial injury in children with asthma. DESIGN: Two patient cohorts were collected. The first, consisting of patients transported for respiratory distress having received at least 10 mg of albuterol, was studied for development of tachycardia and hypotension. The second, consisting of patients who had troponin measured during treatment for status asthmaticus with continuous albuterol, was studied for factors associated with elevated troponin. Exclusion criteria for both cohorts included age younger than 2 years old, sepsis, pneumothorax, cardiac disease, and antihypertensive use. Albuterol dose, other medications, and vital signs were collected. Diastolic and systolic hypotension were defined as an average value below the fifth percentile for age and tachycardia as average heart rate above the 98th percentile for age. PATIENTS: Ninety of 1,390 children transported for respiratory distress and 64 of 767 children with status asthmaticus met inclusion criteria. MEASUREMENTS AND MAIN RESULTS: Diastolic hypotension occurred in 56% and 98% of the first and second cohorts, respectively; tachycardia occurred in 94% and 95% of the first and second cohorts, respectively. Diastolic hypotension and tachycardia had a weak linear correlation with albuterol dose (p = 0.02 and p = 0.005, respectively). Thirty-six percent had troponin > 0.1 ng/mL (range, 0-12.6). In multivariate analysis, interaction between diastolic hypotension and tachycardia alone was associated with elevated troponin (p = 0.02). CONCLUSIONS: Diastolic hypotension and tachycardia are dose-dependent side effects of high-dose albuterol. In high-risk patients with status asthmaticus treated with albuterol, diastolic hypotension and tachycardia are associated with biochemical evidence of myocardial injury. Diastolic hypotension, especially combined with tachycardia, could be a reversible risk factor for myocardial injury related to ß-agonist use.

Serial cardiac troponin concentrations as marker of cardiac toxicity in children with status asthmaticus treated with intravenous terbutaline.

OBJECTIVES: The study's objectives were to evaluate serial troponin concentrations as a marker of cardiac toxicity in children receiving intravenous terbutaline for status asthmaticus and to study if troponin concentrations are affected by severity of asthma and risk factors for severe asthma. METHODS: This was a prospective observational study in 20 consecutive patients who were admitted to a tertiary care pediatric intensive care unit for status asthmaticus and received intravenous terbutaline. Cardiac troponin I (cTnI) concentrations were measured half an hour before the bolus of intravenous terbutaline, 4 hours after terbutaline, and then every 24 hours until discontinuation of the continuous terbutaline infusion. RESULTS: Ten patients had cTnI concentrations greater than 0.03 ng/mL. Maximum cTnI concentrations were recorded after the terbutaline bolus in 6 patients, during terbutaline infusion in 3 patients, and before terbutaline use in 1 patient. Three of these 10 (3/10) patients showed increased cTnI concentrations before the terbutaline bolus. One patient had a significant elevation in cTnI concentration (peak level of 3.79 ng/mL) with electrocardiogram (ECG) changes of myocardial injury that normalized upon discontinuation of terbutaline. All other patients with elevated cTnI concentrations had normal ECG findings. CONCLUSIONS: Elevated cTnI concentrations were observed in 50% of patients treated with intravenous terbutaline for status asthmaticus. Clinically significant cardiotoxicity was not observed except in 1 patient in whom the abnormal ECG findings normalized upon discontinuation of terbutaline. There was no statistically significant difference in asthma severity or in the risk factors for severe asthma in children with and without elevation of cTnI concentrations.

Life-threatening asthma in children: treatment with sodium bicarbonate reduces PCO2.

OBJECTIVES: To assess the effect of administration of sodium bicarbonate on carbon dioxide levels in children with life-threatening asthma (LTA) and to evaluate the clinical effect of this treatment. STUDY DESIGN: Retrospective study. SETTING: A pediatric ICU (PICU) of a tertiary care university hospital. PATIENTS: Seventeen children with LTA who received sodium bicarbonate. MEASUREMENTS AND RESULTS: In January 1999, a new protocol for the treatment of LTA was initiated in our institution, incorporating the use of IV sodium bicarbonate in acidotic patients (pH < 7.15) with refractory status asthmaticus. Since January 1999, sodium bicarbonate was administered to 17 patients; 5 patients received two or three doses of sodium bicarbonate. In three patients, sodium bicarbonate was administered after intubation. Intubation and mechanical ventilation were performed in five patients before admission to the PICU, and in one patient during admission. There was a significant decrease of Pco(2) after sodium bicarbonate infusion (p = 0.007). An improvement of respiratory distress in all but one patient was seen as well. CONCLUSIONS: Administration of sodium bicarbonate in 17 children with LTA was associated with a significant decrease in Pco(2) and an improvement of respiratory distress. The possible benefits of sodium bicarbonate in LTA deserve further study in a controlled, prospective design.

Prediction of intravenous theophylline dosage based on a single, nonsteady-state concentration: a clinical study of childhood status asthmaticus.

A pharmacokinetic model was applied to achieve therapeutic serum theophylline concentrations rapidly in 25 children with status asthmaticus. A sustained release theophylline preparation had been taken within 36 hours by 12 children; within 14 hours, seven had taken an immediate release preparation; for six children, no theophylline was taken before hospital admission. Single serum theophylline concentrations were determined at nonsteady-state conditions within 13.5 hours of admission (median 6.75 hours). An iterative program was applied to predict the steady-state theophylline concentration as well as necessary adjustments in dosage. Measured steady-state concentrations were then compared with the predicted values. The median measured steady-state concentration was 15 mg/L, and the median predicted steady-state level was 13 mg/L. The least squares regression line was: Measured = 0.738 predicted + 4.77; r = .721, P less than .01. No patient experienced symptoms of toxicity. This technique affords the possibility of accurate prediction of steady-state theophylline concentrations and dosing requirements with a minimum number of serum concentration determinations in children with status asthmaticus.

Facilitation of mechanical ventilation in status asthmaticus with continuous intravenous thiopental.

Mechanical ventilation in status asthmaticus is associated with a significant mortality and morbidity. To facilitate intermittent positive pressure ventilation (IPPV), we have used continuous IV thiopental (thiopentone) together with traditional ventilatory techniques. With this policy, we were able to achieve rapid correction of arterial blood gas tensions in a group of 20 severe asthmatics requiring IPPV. By 1 hour, peak airway pressure (PAP) had fallen from 58.6 +/- 15.7 to 30.2 +/- 10.9 cm H2O (p less than 0.001). During the same period, PaCO2 fell from 51.3 +/- 15.3 to 40.17 +/- 8.2 mm Hg (p less than 0.05) and pH rose from 7.25 +/- 0.1 to 7.33 +/- 0.1 (p less than 0.001). Morbidity was low and in particular, no episode of barotrauma was noted. All patients survived the acute attack and were successfully liberated from the ventilator. We conclude that these results are largely attributable to our use of early and continuous IV anesthesia induced by thiopental.

Helium-oxygen mixtures in intubated patients with status asthmaticus and respiratory acidosis.

Seven patients with status asthmaticus intubated for respiratory failure who had elevated airway pressures and persistent respiratory acidosis were successfully ventilated using a mixture of 60 percent helium and 40 percent oxygen. All patients experienced a rapid reduction in airway pressures, CO2 retention, and resolution of acidosis while breathing a helium-oxygen mixture. There were no untoward effects. Helium-oxygen mixtures improve ventilation by reducing the Reynolds number and reducing density dependent resistance. Helium's beneficial effects are due to its high kinematic viscosity, high binary diffusion coefficient for CO2, and high diffusivity. Helium-oxygen mixtures should be considered for use in mechanically ventilated asthmatics with respiratory acidosis who fail conventional therapy.

Non-invasive mechanical ventilation in status asthmaticus.

OBJECTIVE: To evaluate our clinical experience with the use of non-invasive mechanical ventilation (NIMV) in patients with an acute asthmatic attack. DESIGN: Seven-year period retrospective observational study. SETTING: General intensive care department (ICU) of a county hospital. PATIENTS: From 1992 to 1998, we documented clinical data, gas exchange and outcome of every asthmatic patient admitted to our ICU because of status asthmaticus (SA) refractory to initial medical therapy. INTERVENTIONS: Clinical charts were reviewed and patients were allocated to two groups according to their suitability as participants in an NIMV trial. Patients who arrived in respiratory arrest and those who ultimately improved with medical management alone were not considered candidates for NIMV. For the present analysis, the rest of the patients were considered candidates for NIMV, while the decision to start a NIMV trial or to perform endotracheal intubation (ETI) remained at the discretion of the attending physician. When patients failed to improve with NIMV, standard mechanical ventilation (MV) with ETI was initiated. MEASUREMENTS AND RESULTS: Fifty-eight patients were included in the study. Twenty-five patients (43%) were not eligible for NIMV: 11 patients (19%) because of respiratory arrest on their arrival at the Emergency Room and 14 patients (24%) because of improvement with medical management (bronchodilators, corticoids and oxygen). The remaining 33 patients were eligible for NIMV (57%): 11 patients (33%) received invasive MV and 22 patients (67%) were treated with NIMV. Three NIMV patients (14%) needed ETI. We compared data at baseline, 30 min, 2-6 h and 6-12 h after the onset of ventilatory support. Significant differences were observed in arterial blood gases on admission to the Emergency Room between MV and NIMV: PaCO2 (89 +/- 29 mmHg vs 53 +/- 13 mmHg, p < 0.05), pH (7.05 +/- 0.21 vs 7.28 +/- 0.008, p < 0.05) and HCO3- level (22 +/- 5 mmol/l vs 26 +/- 6 mmol/l, p < 0.05). No differences were found in the median length of ICU stay (4.5 vs 3 days), median hospital stay (15 vs 12 days) and mortality (0 vs 4%). CONCLUSION: Face mask NIMV appears to be a suitable method for improving alveolar ventilation and can reduce the need for intubation in a selected group of patients with SA.

Serum magnesium levels in asthmatic children during and between exacerbations.

OBJECTIVE: To determine, if possible, whether magnesium deficiency exists in children with asthma during acute attacks and between exacerbations. SETTING: Emergency Department Clinic and Outpatient Pediatric Clinic of Jordan University of Science and Technology, Irbid. METHODS: A total of 174 known asthmatic children who presented to the emergency department in acute attack (group 1) and 94 asthmatic children who presented to outpatient clinics for follow-up of asthma (group 2) had their serum magnesium levels assayed and compared with 232 patients without asthma (controls; group 3). Exclusion criteria were history of renal disease, cardiac disease, malabsorption, diuretic use, alcoholism, and pregnancy. RESULTS: There were no differences between study groups, although male patients had a slightly lower level of magnesium than female patients. CONCLUSION: After removing the confounder of sex, serum magnesium levels in asthmatic children during acute attacks and between exacerbations are not significantly different from those of controls.

Pressure-controlled ventilation in children with severe status asthmaticus.

OBJECTIVE: The optimum strategy for mechanical ventilation in a child with status asthmaticus is not established. Volume-controlled ventilation continues to be the traditional approach in such children. Pressure-controlled ventilation may be theoretically more advantageous in allowing for more uniform ventilation. We describe our experience with pressure-controlled ventilation in children with severe respiratory failure from status asthmaticus. DESIGN: Retrospective review. SETTING: Pediatric intensive care unit in a university-affiliated children's hospital. PATIENTS: All patients who received mechanical ventilation for status asthmaticus. INTERVENTIONS: Pressure-controlled ventilation was used as the initial ventilatory strategy. The optimum pressure control, rate, and inspiratory and expiratory time were determined based on blood gas values, flow waveform, and exhaled tidal volume. MEASUREMENT AND MAIN RESULTS: Forty patients were admitted for 51 episodes of severe status asthmaticus requiring mechanical ventilation. Before the institution of pressure-controlled ventilation, median pH and Pco(2) were 7.21 (range, 6.65-7.39) and 65 torr (29-264 torr), respectively. Four hours after pressure-controlled ventilation, median pH increased to 7.31 (6.98-7.45, p <.005), and Pco(2) decreased to 41 torr (21-118 torr, p <.005). For patients with respiratory acidosis (Pco(2) >45 torr) within 1 hr of starting pressure-controlled ventilation, the median length of time until Pco(2) decreased to <45 torr was 5 hrs (1-51 hrs). Oxygen saturation was maintained >95% in all patients. Two patients had pneumomediastinum before pressure-controlled ventilation. One patient each developed pneumothorax and subcutaneous emphysema after initiation of pressure-controlled ventilation. All patients survived without any neurologic morbidity. Median duration of mechanical ventilation was 29 hrs (4-107 hrs), intensive care stay was 56 hrs (17-183 hrs), and hospitalization was 5 days (2-20 days). CONCLUSIONS: Based on this retrospective study, we suggest that pressure-controlled ventilation is an effective ventilatory strategy in severe status asthmaticus in children. Pressure-controlled ventilation represents a therapeutic option in the management of such children.

[The changes in total and free catecholamine level in plasma in a patient with status asthmaticus].

Halothane was administered in oxygen to a young man in status asthmaticus whose bronchospasm did not respond to usual treatments. Plasma catecholamine concentrations were measured during and after bronchospasm. Fifteen minute inhalation of halothane produced marked bronchodilatation as reflected in decreased peak airway pressure, decreased wheezing and fall in PaCO2 from 110 mmHg to 45 mmHg. Treatment with halothane was discontinued after 120 min inhalation. Arterial blood samples were obtained to determine free and total catecholamine (CA) on the following four occasions: 1. during status asthmaticus, 2. fifteen minutes after inhalation of halothane, 3. one day after bronchospasm and 4. two days after bronchospasm. During attack, free norepinephrine and epinephrine concentrations were markedly elevated. These values decreased remarkably after administration of halothane. Total norepinephrine and epinephrine were also elevated during bronchoconstriction, and these high concentrations persisted after bronchodilatation. The changes in CA levels suggest that sympathoadrenal hyperactivity elicited by acute asthma can be suppressed by halothane as evidenced by the decreased concentration in free catecholamines, which are physiologically active. The levels in total catecholamine did not correlate with the patient's condition. Therefore, judgement based only on the levels in total CA might lead to misinterpretation in estimating sympathoadrenal activity.

[Relation between serum eosinophil cationic protein (ECP) level and asthma attack in children].

Serum eosinophil cationic protein (sECP) levels were measured in 339 patients with childhood asthma, and the clinical courses of these patients were followed for 57 weeks. While considering the history and characteristics of each patient, we examined the correlation between asthma attack frequency and sECP, blood eosinophil count, and serum total IgE (tIgE) to determine their usefulness in predicting asthma attacks. Among patients with no other allergic diseases, sECP levels in patients who had no asthma attacks two weeks before or after the measurement were significantly lower than those of patients who had attacks during the same four-week period. Among patients who had attacks, those patients with no attack for a year after the measurement were also found to have low sECP levels. Similarly, even among patients with asthma attacks and high sECP levels, there were cases where attacks were well controlled using nebulizer treatments with DSCG or BDP. The incident rate of attacks for patients with other allergic diseases and a low sECP was low. Yet, there was no common trend in patients with high sECP levels. Moreover, this study detected a significant correlation between sECP level and blood eosinophil count as well as between sECP level and serum tIgE. The most significant correlation with asthma attack frequency was sECP level. Thus, sECP level seems to reflect the allergy activity level, especially two weeks prior to and after the measurement. For patients without other allergic diseases, asthma attack prediction during the two weeks period after the measurement of sECP also seems possible. Therefore, periodic measurement of sECP level is useful in objectively monitoring the improvement of symptoms and establishing the treatment plan, including treatment with DSCG or BDP.

[Eosinophil activation markers in status asthmaticus]. / Eosinophil aktivációs markerek status asthmaticusban.

Eosinophil activation markers-eosinophil cationic protein, eosinophil protein-X-were investigated in acute severe asthma. The elevation of the eosinophil activity markers were found in every cases at the time of admission. The measurements were repeated eight days later. The eosinophil cationic protein and eosinophil protein-X levels were increased at the time of the admission, and a decreasing tendency was detected eight days later. The peak expiratory flow rates were monitored during the period of the hospital staying. It is important to note that, the size of the bronchial obstruction did not show any similarity in all cases comparing to the elevation or decrease of eosinophil activity markers. The authors proved the eosinophil activation in vivo in acute severe asthma. The continuous monitor of the eosinophil activity markers might have a practical value in searching of the optimal therapeutic modalities in the asthmatic patients.

[Atherogenesis in bronchial asthma patients: its relationship to the pathogenetic characteristics of the disease and to liver function (the clinico-biochemical aspects)]. / Aterogenez u bol'nykh bronkhial'noi astmoi, ego zavisimost' ot patogeneticheskikh osobennostei zabolevaniia i funktsional'nogo sostoianiia pecheni (kliniko-biokhimicheskie aspekty).

Ten asthmatics in remission and aggravation of the disease were examined for: lipoprotein pre-beta, beta and alpha fractions, total cholesterol and its fractions in atherogenic and antiatherogenic lipoproteins with estimation of the atherogenicity coefficient, activity of 5-nucleotide hydrolase, acid phosphatase, gamma-glutamyl transpeptidase and alcohol dehydrogenase. The results were indicative of more active atherosclerotic process in the presence of blockade which changed the activity of hepatocyte membrane lipoprotein receptors, of simultaneous operation in bronchial asthma patients of infiltrative and cellular mechanisms of atherosclerosis.

Elevated plasma glutathione peroxidase concentration in acute severe asthma: comparison with plasma glutathione peroxidase activity, selenium and malondialdehyde.

OBJECTIVE: To investigate plasma glutathione peroxidase concentration, glutathione peroxidase activity, plasma selenium and oxidative stress in acute severe asthma. MATERIAL AND METHODS: The study was case-control in design, with cases presenting to the emergency department with acute severe asthma and controls randomly selected from a larger cross-sectional study. Plasma malondialdehyde (MDA) was used as a measure of oxidative stress and plasma selenium was measured using ICP-MS. Glutathione peroxidase (GPx) activity was analysed using a colorimetric GPx assay and plasma GPx level was measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: Fifteen cases [mean (range) predicted peak expiratory flow rate (PEFR) of 43% (20-69)] and 15 matched controls were recruited. MDA levels (mean+/-SD) were higher in acute asthma subjects (1.30+/-0.56 micromol/L) than in controls (0.86+/-0.53 micromol/L; p<0.05). There were no differences between cases and controls for selenium (99+/-34 microg/L versus 109+/-17 microg/L) or for GPx activity (39+/-25 nmol min(-1) mL(-1) versus 38+/-24 nmol min(-1) mL(-1)), however, GPx plasma levels measured by ELISA were higher in cases than controls (22.5+/-10.8 mg/L versus 13.8+/-7.3 mg/L; p<0.05). CONCLUSIONS: Patients with acute severe asthma demonstrated increased MDA levels but no differences in plasma selenium levels or GPx activity. GPx levels measured by ELISA were elevated in severe asthma. These results are consistent with an adaptive up-regulation of GPx to protect against oxidative stress.