Diagnosis of cystic fibrosis in the Republic of Ireland: epidemiology and costs.

There were four objectives in this study: (1) determine the incidence of cystic fibrosis (CF) in Ireland; (2) estimate the cost of diagnosing CF; (3) clarify the characteristics and outcomes of the nationwide diagnostic efforts and (4) identify disparities. Surveys were conducted to determine the number, methods, costs and outcomes for sweat tests in Ireland from 2001 through 2003. The results allowed us to determine that Ireland's CF incidence is the world's highest at 1:1353. The average cost for diagnosis was Euro 2663 per patient. Analyses of data in The Cystic Fibrosis Registry of Ireland revealed longer delays when diagnosis followed respiratory symptoms, rather than gastrointestinal signs, and also in girls compared to boys, particularly those presenting with respiratory symptoms. Although expenditures for diagnosing of CF in Ireland are relatively modest, the high incidence and age of diagnosis, as well as gender-related disparities, are sufficient to warrant investment in national newborn screening.

Severe acute asthma in a pediatric intensive care unit: six years' experience.

The management of children with severe acute asthma who required admission to the intensive care (ICU) of this hospital during 1982 to 1988 was reviewed retrospectively. A total of 89 children were admitted to the ICU on 125 occasions. During the study period, 24% of the patients were admitted to the ICU on more than one occasion. Prior to admission to this hospital, patients had been symptomatic for a mean of 48 hours. Although all patients had received bronchodilators before admission to hospital, only 23% of patients had received oral corticosteroids. According to initial arterial blood gas values determined in the ICU, 77% of the patients had hypercapnia (PaCO2 greater than 45 mm Hg). The pharmacologic agents used in the ICU included nebulized beta 2-agonists (100% of admissions), theophylline (99%), steroids (94%), nebulized ipratropium bromide (10%), IV albuterol (38%), and IV isoproterenol (10%). Mechanical ventilation was necessary in 33% of admissions; the mean duration of ventilation was 32 hours. Ten patients had pneumothorax; in six cases, these were related to mechanical ventilation. Three of the patients who received mechanical ventilation died, representing a mortality of 7.5%. In each of these patients, sudden, severe asthma episodes had developed at home, resulting in respiratory arrest. They had evidence of hypoxic encephalopathy at the time of admission to the ICU and eventually were declared brain dead. It was concluded that delay in seeking medical care and underuse of oral corticosteroids at home may have contributed to the need for ICU admission.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute asthma: observations regarding the management of a pediatric emergency room.

Because inadequate assessment and inappropriate treatment of acute asthma have been implicated as contributing factors in morbidity and even deaths, the management of acute asthma, as practiced in an emergency room, were reviewed. The study population comprised 1,864 children (mean age 5.6 years; 65% boys) who attended the emergency room with acute asthma on 3,358 occasions during a 16-month period. Visits occurred more commonly in winter and usually in the evenings; 93% were self-referred and the mean duration of symptoms was 41 hours. Most acute episodes were associated with infection. Although chest auscultation, heart rate, and respiratory rate were recorded during the majority of visits, evidence that pulsus paradoxus had been measured could be found for only 1% of visits. Results of lung function and blood gas values were rarely recorded, but chest radiographs were obtained in 18% of visits. Drugs used in the emergency room included beta 2-agonists (93% of visits), theophylline (16%), and systemic steroids (4%), but no child received anticholinergic therapy. In 26% of patient visits, admission to hospital occurred; one patient died. The erratic fashion in which asthma severity appears to have been assessed and the failure to document whether lung function had been measured are causes for concern. The surprisingly high hospitalization rate may have been avoided if bronchodilators and corticosteroids had not been underused in the emergency room.

Controlled trial of nebulized albuterol in children younger than 2 years of age with acute asthma.

To determine the response to nebulized beta 2 agonist, 28 children younger than 2 years of age who visited the emergency department during an episode of acute asthma were studied. Each subject had a previous history of recurrent wheezing episodes. They were randomly assigned to receive two administrations of either nebulized albuterol (0.15 mg/kg per dose) or placebo (normal saline) with oxygen, 1 hour apart. After two nebulizations, the albuterol-treated patients had a greater improvement in clinical status (respiratory rate, degree of wheezing and accessory muscle use, total clinical score, and arterial oxygen saturation) than the placebo group. None of the patients in the albuterol group experienced a decrease of arterial oxygen saturation of greater than or equal to 2%. It is concluded that a trial of nebulized beta 2 agonists is warranted in the treatment of acute asthma in infants and young children.

Effects of nutritional status on exercise performance in advanced cystic fibrosis.

Initial evaluation of 22 patients with cystic fibrosis (CF) on entry into a trial of home oxygen therapy was used to elucidate the possible effects of poor nutritional status on exercise performance in CF. The patients had advanced lung disease (mean FEV1, 36 percent predicted) and all had a stable resting PaO2 less than or equal to 65 mm Hg. Nutritional status was determined by calculating weight as a percentage of ideal for height (Wt/Ht) for each subject. Exercise testing consisted of a progressive exercise test on a cycle ergometer to measure maximum work capacity (Wmax), and a steady state test at 50 percent of baseline Wmax. During the steady state test, cardiac output (Q) and stroke volume (SV) were computed by the indirect Fick (CO2) method. Wmax, SV, Q and lung function results are expressed as percent predicted. Mean (+/- SD) Wmax was 58 +/- 15 percent predicted. Wmax correlated with both FEV1 and Wt/Ht, but FEV1 and Wt/Ht were not related. During steady state exercise, 12 of 22 patients had a SV less than 80 percent predicted. SV correlated with Wt/Ht, but not with lung function. Thirteen of the 22 patients had a Wt/Ht less than or equal to 90 percent and were considered malnourished. When compared with the well-nourished patients (Wt/Ht greater than 90%), these malnourished subjects had significantly lower mean values for Wmax%, SV% and Q% predicted, but not for lung function parameters. We conclude that: in patients with CF and advanced lung disease, nutritional status plays a significant role in determining exercise capacity; lower exercise tolerance of malnourished patients is an independent effect, as nutritional status and lung function were not related; and malnourished patients with CF have an altered cardiac performance on exercise testing which is due to a reduced SV rather than an impaired heart rate response.

Pregnancy and cystic fibrosis.

Despite reduced fertility, pregnancy is likely to occur with increasing frequency in cystic fibrosis in proportion to the number of patients reaching childbearing age. Thirty-eight pregnancies in 25 patients with cystic fibrosis are presented. Twelve of the 25 mothers were pancreatic-sufficient. Despite previous reports of the hazards of pregnancy in cystic fibrosis, we found that pregnancy was well tolerated by the vast majority of our patients and had little effect on their pulmonary and nutritional status. Therapeutic abortion for medical indications was required in two pregnancies. The incidence of prematurity and the neonatal mortality rate were low, and no congenital abnormalities occurred. We conclude that pregnancy can be tolerated by the majority of cystic fibrosis patients, particularly those who are pancreatic-sufficient.

Exercise response and rehabilitation in cystic fibrosis.

Exercise testing can be performed safely in cystic fibrosis patients, and provides a simple and reproducible index of overall health in the disease. A wide variability in exercise capacity of cystic fibrosis patients is found, but, in general, exercise is limited by the degree of lung disease and, to a lesser extent, by compromised nutritional status. Based on the results of exercise tests, patients can then be supplied with individualised exercise prescriptions. Exercise training can be expected to improve the exercise capacity of the majority of cystic fibrosis patients, but pulmonary function generally remains unchanged. Whether exercise rehabilitation will improve the long term prognosis for patients with cystic fibrosis is currently not known.

Forced vital capacity and maximal respiratory pressures in patients with mild and moderate scoliosis.

Lung function and maximal respiratory pressures of 24 adolescent females with mild-to-moderate idiopathic scoliosis (spinal curvature 10-60 degrees) were determined and compared with 38 age- and sex-matched controls. Twelve patients with moderate scoliosis (Cobb angle 35-60 degrees) had significantly reduced mean values for FVC (% predicted) and maximal inspiratory pressure (MIP), as compared to the controls. Twelve patients with mild scoliosis (Cobb angle less than 35 degrees) had normal mean values for FVC and maximal respiratory pressures, but five individual patients had FVC values less than 80% predicted. All but one of the patients with mild scoliosis had normal MIP values. FVC (% predicted) was significantly correlated with the degree of spinal curvature (r = -0.466; P less than 0.05) but was not related to MIP. These results indicate that reduced FVC values do occur in patients with mild-to-moderate idiopathic scoliosis and suggest that these low FVC values can be attributed to the rib cage deformity rather than to an inability to generate adequate inspiratory pressures.

Hypercapnia in relation to pulmonary function in Duchenne muscular dystrophy.

Arterialized blood gases were analyzed in 143 patients with Duchenne muscular dystrophy (DMD) to assess the relationship between forced vital capacity (FVC) and hypercapnia. The majority of patients studied had PaCO2 values in the low or normal range. Only six older patients had hypercapnia (PaCO2 greater than or equal to 45 mm Hg), and all these patients had FVC values less than or equal to 40% predicted. We conclude that hypercapnic respiratory failure occurs as a late preterminal event in DMD.

The role of corticosteroids in respiratory diseases of children.

Glucocorticosteroids are potent anti-inflammatory agents and have an important role in a variety of respiratory diseases. Although their exact mode of action is unknown, it is thought that they exert their effects by binding to cytoplasmic glucocorticoid receptors. In certain conditions, such as asthma, the value of steroids cannot be questioned, and inhaled steroids have revolutionized management. In other situations, such as interstitial lung disease, the true role of steroids is still to be defined. In the management of diseases such as tuberculosis, the use of steroids is solely based on anecdotal experience.

Multiple factors limit exercise capacity in cystic fibrosis.

Exercise testing was performed in 50 patients with cystic fibrosis to determine whether hemodynamic factors limit exercise capacity in the disease. Prior to exercise testing, lung function and blood gas values were measured. Nutritional status was determined by calculating a weight for height (Wt for Ht) ratio for each subject. A progressive exercise test was used to determine maximum work capacity (Wmax). Cardiac output (Q) (indirect Fick method), and stroke volume (SV) were computed during steady-state exercise at 50% Wmax in 21 of 50 patients. Wmax, SV, Q, and lung function results are expressed as per cent predicted. The mean (+/- SD) Wmax was 75 +/- 23%. Multiple regression analysis showed that maximum voluntary ventilation, resting PaO2, and Wt for Ht accounted for 84% of the variance in Wmax. Although some patients had a reduced SV (mean = 96%) during steady-state exercise, all patients achieved a normal cardiac output (mean = 115%). SV correlated with resting PaO2 but not with lung function. We conclude that exercise capacity in cystic fibrosis is influenced by lung function, nutritional status, and resting hypoxemia, but not by cardiac function; the SV limitation noted in some patients may be due to increased pulmonary vascular resistance related to hypoxemia.

Comparison of airway reactivity induced by cold air and metacholine challenges in asthmatic children.

Bronchial responsiveness to isocapnic hyperventilation with cold air (CAH) and to inhaled methacholine (MCH) was compared in 17 children with bronchial asthma. The response to cold air was expressed as the percent drop in FEV1 from baseline at 4 min. after the challenge (delta % FEV1 CAH), and the response to methacholine as the provocative concentration required to reduce the FEV1 by 20% from baseline (PC20MCH). Both tests were sensitive (94%) for detecting airway hyperreactivity. There was no statistically significant relationship between delta % FEV1 CAH and the log PC20MCH (r = 0.39; P = 0.12). In clinical practice, methacholine test is easier to perform, but in the research field cold air challenge may be preferable because it avoids potential drug effects.

Aerosols--therapeutic use and delivery in childhood asthma.

Aerosol therapy has dramatically improved the lifestyle of the children with asthma, reflecting both the availability of more effective and safer drugs and alternative methods for their delivery. Inhaled treatment with bronchodilators, cromolyn, and inhaled corticosteroids, used singly or in various drug combinations, can control all but the most intractable asthmatic. It is essential that the inhalational device prescribed is appropriate for the child's age and that careful instructions are given as to optimal inhalation technique. Infants and young children with asthma should be given a trial of inhaled bronchodilators, recognizing the limitations this treatment may have in this age group.

Childhood asthma: a rational approach to treatment.

Asthma is a common, but frequently underdiagnosed and undertreated, condition in childhood. In most children, the diagnosis of asthma can be made on the basis of history, physical examination, and simple investigations. Successful management of asthma is contingent upon both patient and parents having a clear understanding of the condition, the goals, and specific details of treatment. The majority of children with asthma can be managed by avoidance of provoking factors, and suppression of symptoms with drug therapy. Drug therapy should follow a logical scheme such that a child with mild, infrequent asthma attacks would receive intermittent bronchodilator therapy, whereas a child with severe chronic asthma would ultimately be treated with maintenance steroids. Response to therapy should be assessed by serial measurement of pulmonary function. Certain features peculiar to infantile asthma demand a modified approach to the management of asthma in this age group.

Methacholine inhalational challenge in the evaluation of chronic cough in children.

The medical records of 58 children (age range, 7 to 16 years) who presented with chronic cough were retrospectively analyzed to determine the value of methacholine (MCH) bronchial challenge in reaching a specific diagnosis. Baseline lung function tests were normal in all subjects, apart from an elevated residual volume/total lung capacity ratio (RV/TLC) in 11 patients, and a reduced midexpiratory flow rate (FEF25-75) in five of these patients. Thirty-one patients had a positive response to MCH, but these patients could not be identified on the basis of clinical criteria or spirometric parameters. MCH-positive patients did have a significantly higher RV/TLC than did MCH-negative patients. Twenty-seven of the 31 MCH-positive patients responded to a trial of bronchodilator therapy (albuterol/theophylline), confirming the diagnosis of cough variant asthma in these patients. We conclude that children with chronic cough should be considered for methacholine challenge in order to identify patients who are likely to benefit from specific bronchodilator therapy.