CONFERENCE NEWS UPDATE
EUROPEAN RESPIRATORY SOCIETY ANNUAL CONGRESS

Findings demonstrating the efficacy of a new protocol for weaning unconscious patients from mechanical ventilation were presented at the Annual Congress of the European Respiratory Society in Madrid, Spain. Other highlights of that meeting included a report that montelukast significantly improves exercise performance parameters in asthmatic patients without causing cardiac side effects and new evidence that eosinophilic inflammation plays a role in exercise-induced bronchoconstriction but not in methacholine-induced hyperresponsiveness.

OSA SEVERITY IS LINKED TO THE INTENSITY OF NOCTURNAL CARDIAC DYSRHYTHMIAS

The severity of obstructive sleep apnea correlates with the maximum intensity of nocturnal cardiac dysrhythmias, according to findings reported by Zoltán Tomori, MD, of Safárik University in Kosice, Slovakia, and colleagues. The data support the researchers' previous findings of a causal relationship between hypercapnia and cardiac dysrhythmias during reversible apneic episodes in cats.

The researchers analyzed polysomnographic records from 15 patients with obstructive sleep apnea to determine both the incidence and intensity of nocturnal cardiac dysrhythmias. A 10-point graded scale was used to estimate sinoatrial and atrioventricular blocks, as well as ventricular and supraventricular premature beats or rhythms.

The highest degree of nocturnal cardiac dysrhythmia was found to correlate significantly with both the respiratory disturbance index (P = .03) and minimum oxygen saturation (P = .01) but was not correlated with either the total number of obstructive apneas, the ratio of obstructive/central apnea, mean oxygen saturation, or body mass index.

THE ROLE OF EOSINOPHILS IN EXERCISE-INDUCED BRONCHOCONSTRICTION

Asthmatic patients experienced eosinophilic inflammation in response to exercise but not to a methacholine challenge in a recent study by C. Micheletto, MD, and colleagues from Bussolengo General Hospital in Italy. The findings emphasize the role of eosinophil inflammation in sustaining exercise-induced bronchoconstriction.

Sixteen nonsmokers with mild asthma (age, 18 to 52 years) were enrolled in the study. Serum level of eosinophilic cationic protein (s-ECP), percentage of blood eosinophils in the total white cell count (Eos%), and forced expiratory volume in 1 second (FEV1) were measured after a 3-week washout period. Each patient then underwent a methacholine challenge, which was followed 2 days later by an exercise challenge.

At baseline, mean s-ECP and Eos% were 15.6 µg/L and 5.7%, respectively. The mean provocative dose of methacholine required to cause a 20% fall in FEV1 from baseline level was 636 µg. The mean maximum percent fall in FEV1 from baseline on the exercise challenge was 19.3%. Exercise-induced bronchoconstriction was significantly related to both s-ECP (P < .001) and Eos% (P < .04); in contrast, the methacholine-induced response was not related to either of these variables.

The findings suggest that eosinophilic inflammation plays a role in exercise-induced bronchoconstriction but that other factors (eg, airway wall remodeling or autonomic dysfunction) are involved in methacholine-induced hyperresponsiveness, according to the researchers.

NOT ALL PULMONARY FIBROSIS PATIENTS NEED TREATMENT

Treatment of idiopathic pulmonary fibrosis (IPF) may not be indicated for all patients, according to findings from a recent study. Antonio Xaubet, MD, of the University of Barcelona, Spain, and colleagues found that selected patients with this condition remained stable for about 1 year without treatment.

A total of 39 patients with IPF were followed for a mean of 24 months. Treatment was initiated at diagnosis in 26 patients (group 1) but not in 13 patients (group 2). Indications for treatment included an increase in the degree of dyspnea and a more than 15% fall in forced vital capacity (FVC) or in the lungs' diffusing capacity for carbon monoxide.

At diagnosis, the patients in group 1 had a significantly lower mean FVC (56% vs 73%; P = .0004) and a significantly greater extent of ground-glass pattern on high-resolution computed tomography scan (18% vs 4%; P = .004) than did those in group 2. A total of 13 of the 26 patients in group 1 died a mean of 11 months after the initial assessment.

In group 2, treatment was initiated in 7 of the 13 patients at a mean of 12 months after diagnosis. The remaining 6 untreated patients (15% of the entire group) had stable disease during the follow-up period.

There were no significant differences in terms of physiological variables among the patients who were treated during the study period and the 6 patients who remained untreated. "These findings may have implications for the initiation of drug therapy, in light of both the limited efficacy and side effects of the drugs used to treat IPF," according to the researchers.

MONTELUKAST IMPROVES EXERCISE PERFORMANCE IN ASTHMATIC PATIENTS

In a recent study, montelukast was associated with significant increases in exercise performance parameters in asthmatic patients. The drug did not appear to cause cardiac side effects or to change the resting metabolism, reported E. Kalmanova, MD, and colleagues from the Pulmonology Research Institute in Moscow.

Seventeen asthmatic patients were randomized to 10 mg/d montelukast or no treatment for 14 days; the two groups then switched treatment options for an additional 14 days. Respiratory function tests, measurements of exercise and resting metabolism, and 24-hour electrocardiography were used to evaluate the subjects during the study period.

Figure

The Effects of Montelukast on Metabolic Parameters

*Data extracted from Kalmanova E et al. Influence of montelukast on exercise and resting metabolism in asthmatic patients. Eur Respir J 1999;14(suppl 30):89s.

PERIPHERAL AIRWAY INFLAMMATION IN PATIENTS WITH EMPHYSEMA

Inflammation of the peripheral airways-but not of the pulmonary arteries and lung parenchyma-was found in specimens taken from patients with severe emphysema who underwent lung volume reduction surgery, a new study indicates.

Marina Saetta, MD, of the University of Padova, Italy, and colleagues compared surgical specimens obtained from seven smokers who underwent lung volume reduction surgery and from four nonsmoking controls who underwent lung resection for localized pulmonary lesions.

In comparison with the control group, the smokers had significantly increased inflammatory cell infiltration in peripheral airways. In contrast, the two groups were not significantly different in terms of inflammation in the pulmonary arteries and lung parenchyma.

PROTOCOL TO WEAN UNCONSCIOUS PATIENTS FROM THE VENTILATOR

New findings suggest that it is possible to wean unconscious patients from mechanical ventilation. Eight of 14 unconscious patients were successfully weaned using a protocol developed by D. Gross, MD, and colleagues from the Tel-Aviv Sourasky Medical Center and Reut Medical Center in Tel Aviv, Israel.

Lack of consciousness was caused by stroke in 7 patients, postsurgical anesthetic complications or congenital brain damage in 5 patients, and posttraumatic head injury caused by an accident in 2 cases. The patients had been chronically ventilated for 2 to 12 months before inclusion in this study.

The weaning protocol, which commenced after the patients were stabilized nutritionally, consisted of short trials of near-spontaneous breathing bouts a few times daily. These bouts were separated by at least 30 minutes of rest with ventilatory assistance.

Patients who were able to breathe spontaneously for at least 1 hour began breathing exercises through inspiratory resistance (6 cm H2O/L/s); each session lasted 5 to 10 minutes and was repeated a few times daily. When patients were free of mechanical ventilation for the whole day, the night weaning protocol was initiated. Of the 14 patients enrolled in the study, 8 patients were successfully weaned within 2 to 8 weeks. "Most of those not weaned most likely had impaired respiratory centers in the brain," according to the researchers.

ASTHMA MANAGEMENT FOR PATIENTS WITH ARRHYTHMIAS

A combination of albuterol and ipratropium bromide as treatment for asthma exacerbations may be preferable to albuterol alone in patients at high risk for arrhythmias, according to findings presented by Michael B. Anthracopoulos, MD, and colleagues from the University of Patras in Greece.

Sixteen asthmatic children ages 6 to 15 years who did not have heart disease were randomized to a 0.15-mg/kg dose of albuterol or a combination dose of 0.1 mg/kg albuterol and 5 &#181g/kg ipratropium bromide for treatment of asthma exacerbations. Three inhalations of the respective treatments were given at 20-minute intervals. Spirometry was performed at baseline and 15 minutes after inhalation. Heart rate variability-a measure of autonomic nervous system balance over time-was assessed by Holter monitor at baseline, immediately after inhalation, and 10 minutes after inhalation.

The treatments resulted in a similar improvement in spirometric parameters. However, the combination treatment, when compared with albuterol alone, shortened the time to reduce the high-frequency power component of heart rate variability. In addition, combination therapy resulted in faster reductions and longer durations of the low-frequency power component and the total power component of heart rate variability. All these differences were statistically significant. Albuterol alone took longer to reduce the standard deviation of all normal sinus RR intervals and maintained that reduction for a shorter period.

The findings suggest that the combined treatment provides an earlier and longer domination of the sympathetic over the parasympathetic nervous system. These findings "may have clinical implications for the management of patients at high risk for arrhythmias," the researchers noted.

TELEPHONE FOLLOW-UP IS FEASIBLE FOR ASTHMATIC PATIENTS

Researchers from the University of Aberdeen in the United Kingdom have found that telephone follow-up for asthmatic patients who present to the emergency department is "pragmatically feasible." Furthermore, telephone follow-up may increase clinic attendance, reported Mariesha A. Jaffray, MD, and colleagues.

The study population consisted of 203 patients, ages 14 to 62 years (mean, 26 years) who presented to the emergency department with symptoms of asthma but were not admitted to the hospital. The patients were randomized to chest clinic follow-up or no follow-up and to telephone follow-up or no telephone follow-up in a 2 X 2 study design. Telephone follow-up consisted of a standardized telephone questionnaire administered by a trained asthma nurse. Three attempts at contact were made.

Of the 82 patients randomized to telephone follow-up who had a telephone number, 63% were contacted a median of 7 days after initial presentation. Of the 82 patients randomized to clinic follow-up who lived locally, 52% maintained their appointment schedules a median of 23 days after initial presentation. Patients who were contacted by telephone were more likely to attend their clinic appointment compared with patients who were not telephoned (72% vs 44%; P < .05).