Home measurement of oxygen saturation during sleep in patients with cystic fibrosis.

Feasibility and reproducibility of home measurement of arterial oxygen saturation (SaO2) were evaluated in 14 clinically stable patients with cystic fibrosis (CF). Changes in SaO2 during sleep were compared to the clinical status and pulmonary function while awake to identify predictors of nocturnal oxyhemoglobin desaturation. Each patient was assessed by clinical score, spirometry, and arterial blood gas analysis within 72 hours of the overnight study. Eight patients were studied on more than one occasion to assess dependence of SaO2 on position and reproducibility of overnight studies. A pulse oximeter stored up to 8 hours of nocturnal SaO2 measurements in its memory. Off-line analysis of trend data provided the proportion of sleep with SaO2 less than 90% and less than 85%. We found that patients with daytime PaO2 less than 60 mm Hg spent greater than 80% of their sleep with SaO2 less than 90%, while those with PaO2 greater than 70 mm Hg spent less than 20% of the night with SaO2 less than 90%. Patients with daytime PaO2 of 67-70 mm Hg were desaturated to less than 90%, from 0 to 98% of the night. No consistent body position dependence of daytime SaO2 was found. Home measurement of SaO2 during sleep was reproducible, with a difference on two repeat occasions of 4% +/- 2 (mean +/- SEM) for %time with SaO2 less than 90% and 3% +/- 2 for %time with SaO2 less than 85%. The severity of hemoglobin desaturation during sleep could not be reliably predicted from clinical scores or awake pulmonary function.(ABSTRACT TRUNCATED AT 250 WORDS)

Is bronchiolitis in infancy an antecedent of chronic lung disease in adolescence and adulthood?

Acute bronchiolitis in infancy appears to be associated with persistence of wheezing or subsequent asthma in later life. Chest imaging techniques have demonstrated persistent structural lung damage such as atelectasis, bronchiectasis, and obliterative bronchiolitis among survivors of the more severe forms of bronchiolitis. In addition, in a significant number of survivors without demonstrable structural damage, pulmonary function studies have revealed a spectrum of disturbances including air-trapping, reduced air flow at low lung volumes, hypoxemia (all indicating disease in the small airways), and bronchial hyperreactivity. However, it has not yet been proven definitively whether the relationship between severe bronchiolitis in infancy and chronic obstructive lung disease is causal or noncausal. Further prospective clinical studies are needed to resolve this question.

Cystic fibrosis in the adolescent and adult.

Modern comprehensive therapy for CF now allows the survival of patients into adulthood. In addition, more patients are being diagnosed for the first time in adolescence or early adulthood. As a result, over 20% of all CF patients are aged 18 years or older. The clinical and radiologic features of the older patients differ from those of pediatric patients and are discussed in this article. However, as with the pediatric patients, chronic lung disease remains the major cause of morbidity and is, almost uniformly, the cause of death in adolescent and adult CF. The plain chest radiograph remains a vital tool not only for diagnosis but as a simple method for establishing a baseline at diagnosis and quantifying serial changes as the patient ages.

Noninvasive determination of total respiratory system compliance in infants by the weighted-spirometer method.

The weighted-spirometer method for noninvasive determination of static total respiratory system compliance (Crs) was adapted for use in infants. Ten normal newborns and 5 infants with bronchopulmonary dysplasia (BPD) were studied. The newborns had a mean Crs of 3.8 ml/cm H2O. Their mean specific Crs was 1.13 ml/cm H2O/kg body weight and 0.075 ml/cm H2O/cm body length. These Crs values were similar to those reported by other investigators who used the Hering-Breuer airway occlusion technique. The infants with BPD, who were of the same weight, height, and postconception age as the normal newborns, had significantly (p less than 0.05) lower mean specific Crs (0.60 ml/cm H2O/kg body weight and 0.047 ml/cm H2O/cm body length) relative to the normal newborns. These data suggest that intrinsic changes in lung elastic characteristics may contribute to the reduced lung compliance of infants with BPD. The weighted-spirometer method for measuring Crs is a potential tool for the noninvasive study of the elastic properties of the respiratory system during infancy in health and disease.

Fatal lower respiratory tract infection due to herpes simplex virus in a previously healthy child.

A well-nourished, previously healthy, 9-month-old baby died of herpes simplex virus infection of the lower respiratory tract, without apparent dissemination. The herpetic disease followed bacterial pneumonitis for which the patient had had tracheal intubation.

Sex differences in growth patterns of the airways and lung parenchyma in children.

Seventeen boys and 19 girls, 8-15 yr in age, were studied to ascertain, in the two sex groups, the predictors of airway size [assessed by measurement of tracheal cross-sectional area (CSA) and maximal expiratory flows (Vmax)] and the relative rates of growth of the major divisions of the airways and lung parenchyma. In boys, total lung capacity (TLC) accounted for 77% of the variance of CSA and for 66% of the variability of Vmax. In contrast, somatic growth and maturation in girls accounted for only 45% of the variance of CSA and for 64% of the variability of Vmax; TLC was relatively unimportant. In boys, but not in girls, TLC-corrected CSA was significantly and inversely related to height and to TLC. In girls, TLC-corrected Vmax at 50 and 75% of forced vital capacity were directly related to height. These observations suggest different patterns of airway-parenchymal-somatic growth relationships in the two sexes. Furthermore, parenchymal growth appears to be the best determinant of airway growth in boys. In girls, other factors, perhaps genetic in nature, besides growth of parenchyma, may help determine airway size.

Disseminated tuberculoid lesions in infants following BCG vaccination.

The records of 830 consecutive autopsies at Children's Hospital, Winnipeg revealed that 26 of the 36 infants (34 Canadian Indian, 1 Inuit and 1 Caucasian) given BCG vaccine shortly after birth had tuberculoid granulomas in various sites, including the vaccination site, regional lymph nodes, liver, spleen, lung, bone marrow and salivary gland. Mycobacterium bovis, BCG type, was identified in three of the four cases in which isolation was attempted. The principal causes of death had been sudden infant death syndrome and respiratory tract infections. None of the infants had histologic evidence of an immune deficiency. However, it is possible that in two cases the dissemination of BCG was enhanced by a temporary immunologic defect induced by malnutrition.

Adenovirus bronchiolitis in Manitoba: epidemiologic, clinical, and radiologic features.

We reviewed our experience with 41 children hospitalized from 1974 to 1978 for adenovirus (ADV) bronchiolitis. Thirty-two patients (78 percent) were native Indians between four and 12 months old. In 18 of the 41 patients (43.9 percent) acute complications developed. The five fatal cases (12.2 percent) were confined to native children. The initial chest roentgenograms showed lobar consolidation in 35 patients (85.4 percent). Atelectasis developed in five (12.2 percent) during hospitalization. Sixteen of 25 patients (64 percent) with adequate radiologic follow-up examination had subsequent pneumonias or showed residual chronic changes. The reasons for the predilection of ADV bronchiolitis in native Indian children and the precise effect on subsequent airway function in survivors are unknown and require further study. We emphasize the importance of ADV as a cause of bronchiolitis in native Indian children. Furthermore, this report focuses attention on the contribution of this disease to the spectrum of chronic pulmonary disorders in the pediatric group.

Xenon-133 ventilation and perfusion studies in bronchiectasis.

Thirty-nine Xenon-133 ventilation and perfusion studies in 36 patients with bronchiectasis were analyzed retrospectively. These patients showed a marked reduction in ventilation with a less severe reduction in pulmonary arterial perfusion, resulting in areas of low ventilation-perfusion ratios. In those patients with bronchographic confirmation, xenon studies had greater sensitivity (0.89) than the chest radiographs (0.71). Where both the radiograph and the scan are normal, bronchiectasis is virtually excluded; therefore bronchography is not indicated.

Terbutaline elixir in preschool children with chronic asthma.

In a double-blind, single-dose trial asthmatic children, ages two to six years, received 25, 50 or 100 ug/kg terbutaline and placebo on four consecutive days. After ingestion of all doses and placebo mean pulmonary index score and mean total respiratory resistance (Rrs), measured by forced oscillation decreased significantly at 0.5, 1, 2, 3 and 4 hours, with maximal decrease at two hours. A dose response was apparent but was significant only between doses of 25 ug/kg and 50 ug/kg at four hours. Adverse effects included elevation of heart rate two hours after the 100 ug/kg dose and tremor. In a subsequent nine-week, single-blind trial clinical wheezing was completely prevented by terbutaline 50 ug/kg tid in five of eight patients and by 75 or 100 ug/kg tid in two patients. Baseline Rrs did not decrease. No adverse ophthalmologic, hematologic or biochemical changes were observed.

Radiologic features of miliary tuberculosis in children and adults.

We reviewed the radiologic features of 19 children and 26 adults with miliary tuberculosis. Children had a very high prevalence of associated lymph node enlargement compared to the adults (95% vs. 12%). Pulmonary consolidation was more common in children (42% vs. 12%). Pleural effusions were uncommon in both groups. The miliary pulmonary lesions cleared faster in children. Evidence of previous tuberculosis was seen in 31% of the adults but none of the children. Most of these differences in radiologic features between children and adults probably represent differences in pathogenesis for hematogenous spread in the two groups.

Role of peripheral and central chemoreceptors in the initiation of fetal respiration.

The relationship between fetal femoral arterial P02 and PC02 was evalulated in 13 fetal sheep with intact and denervated peripheral chemoreceptors. With intact chemoreceptors, a significant relationship was found between fetal Pa02 and PaC02 at the time of the first breath (Pa02 = 2.57 + 0.09 PaC02; r = 0.62, P less than 0.05)mfollowing bilateral carotid sinus nerve section (CSN) or total peripheral chemodenervation (TD), PaC02. Comparison of the intact, CSN, and TD blood gases at the time of the first breath demonstrated that a) severe hypoxemia stimulates fetal respiration even following total peripheral chemodenervation; b) fetal central chemoreceptors do not respond to PaC02; c) PaC02 acting via peripheral chemoreceptors has a minor modulating effect on the degree of hypoxemia required to initiate fetal respiration. At a PaC02 below 40 mmHg this effect is inhibitory, acting via the carotid body. At a PaC02 above 90 mmHg this effect is stimulatory, acting via both carotid and aortic bodies.

Bronchopulmonary dysplasia and lung rupture in hyaline membrane disease: influence of continuous distending pressure.

Review of 158 patients with hyaline membrane disease was undertaken. The introduction of artificial ventilation with a positive end-expiratory pressure (IPPB and PEEP) has doubled the prevalence of pneumothorax, pneumomediastinum and interstitial emphysema from 20.7% to 39.7%). Continuous negative distending pressure during spontaneous ventilation (CNP) was associated with a prevalence of lung rupture similar to that occurring spontaneously (4.8%). No patient treated with CNP alone developed bronchopulmonary dysplasia. Patients treated with IPPB with PEEP had a marked decreased prevalence of bronchopulmonary dysplasia (17.2%) when compared to patients treated with IPPB alone (36.2%), probably related to the enhanced overdistension of relatively normal areas of the lung may be related to the increased prevalence of lung rupture seen during IPPB with PEEP.