Biomedical subjects

G J Redding

Publications and source records attributed to G J Redding.

44 records · Page 3Linked to original sources

PubMed1985

Sleep patterns in nonambulatory boys with Duchenne muscular dystrophy.

Sleep patterns and respiratory function during sleep were studied in five nonambulatory boys with Duchenne muscular dystrophy to clarify why patients with this disease awaken frequently at night. It was hypothesized that hypoxemia during sleep due to severe restrictive lung disease might cause nighttime arousals. Each boy underwent electroencephalography, electro-oculography and electromyography. Also determined were arterial oxyhemoglobin saturation, airflow from the nose and mouth, chest and abdominal excursions, and carbon dioxide tension of exhaled breaths. All five subjects had pulmonary function abnormalities consistent with severe restrictive lung disease and respiratory muscle weakness but none had evidence of respiratory failure or cor pulmonale. The boys awakened three times more frequently than age-matched published norms and experienced sleep stage shifts twice as often as normal children. Rapid-eye movement (REM) sleep as a proportion of total sleep was significantly reduced; sleep stage I was increased compared to normal values. No subject developed oxyhemoglobin desaturation during sleep. End-tidal CO2 tensions rose during sleep stages I, II and V (REM) in association with reduced chest wall excursion, suggesting transient episodes of mild hypoventilation which were not associated with arousals. Sleep fragmentation, frequent arousals and REM sleep deprivation occur in some boys with Duchenne muscular dystrophy but are not associated with significant disorders in breathing during sleep.

Adolescent↗

PubMed1984

Atelectasis in childhood.

The clinician who identifies atelectasis in a child must determine the mechanism by which atelectasis developed, the functional significance of the collapsed lung, and the etiology responsible for its presence. This article provides a framework to help physicians address these issues and thereby elect the most rational diagnostic and therapeutic interventions at the most appropriate time.

Age Factors↗

PubMed1984

Nifedipine attenuates acute hypoxic pulmonary vasoconstriction in awake piglets.

The calcium channel blocker nifedipine was administered to awake piglets to determine the drug's potential efficacy as a pulmonary vasodilator in newborns. We hypothesized that nifedipine attenuates acute hypoxic pulmonary vasoconstriction in this age group. Hemodynamic and arterial blood gas measurements were made in 24 catheterized piglets, 10 +/- 3 days of age, while they breathed room air and then 12% O2, 4% CO2, and 86% N2 gas. Thirteen piglets were studied before and after infusions of 15 and 40 micrograms X kg-1 X min-1 of nifedipine prior to hypoxia to see if the drug prevents hypoxic pulmonary vasoconstriction. In 7 animals, nifedipine was administered after the onset of hypoxia to see if the drug reduces ongoing hypoxic pulmonary vasoconstriction. Nifedipine significantly increased heart rate (56 +/- 28%) and cardiac output (48 +/- 45%) and decreased systemic artery pressure (-11 +/- 7%) and systemic vascular resistance (-37 +/- 18%) compared with pretreatment values under normoxic conditions. Pulmonary artery pressure increased (28 +/- 21%) after nifedipine treatment, but total pulmonary resistance remained unchanged during normoxia. Nifedipine did not reduce pulmonary artery pressure compared with pretreatment values during hypoxia, but reduced the elevation in total pulmonary resistance associated with hypoxia by 45 to 99% in a dose-dependent manner. We conclude that nifedipine vasodilates the constricted pulmonary vasculature associated with hypoxia in newborns but that this effect is manifested primarily by a rise in cardiac output rather than by a reduction in pulmonary artery pressure in this age group.

Animals↗

PubMed1984

Multiple pulmonary complications in a patient with Stevens-Johnson syndrome.

Since first described in 1922, Stevens-Johnson syndrome has been associated frequently with pneumonia of many etiologies. This "mucosal respiratory syndrome," first reported by Stanyon and Warner in 1945, is associated with "early" pneumonia which resolves 2 to 3 weeks after onset of the rash. In our patient, pneumonia began 10 days after rash onset and was nearly resolved by day 20. The unique feature of this case was the onset of late pulmonary complications 25 days after the appearance of the exanthem, manifesting as acute noninfectious interstitial disease with superimposed airway obstruction.

Airway Obstruction↗

PubMed1984

Effects of meclofenamate on pulmonary vascular resistance correlate with postnatal age in young piglets.

We administered sodium meclofenamate, a prostaglandin synthetase inhibitor, to 15 piglets (ages 5-70 d) to test the hypothesis that endogenous prostaglandin pulmonary vasodilators influence total pulmonary resistance under both normoxic and hypoxic conditions. No significant differences in hemodynamic measurements were found between the control group and drug-treated animals more than 12-d-old. When six experimental animals less than 12 d of age were compared with six age-matched controls, meclofenamate produced a small but significant increase in mean pulmonary artery pressure (110 +/- 9 versus 97 +/- 10%, P less than 0.05) and total pulmonary resistance (135 +/- 23 versus 102 +/- 12%, P less than 0.03). The magnitude of the change in total pulmonary resistance produced by 2 mg/kg of meclofenamate during normoxia correlated inversely with postnatal age (r = 0.83, P less than 0.01). Individual changes in pulmonary hemodynamics produced by acute hypoxia after meclofenamate treatment were the same as pretreatment values and were similar in both young and older animals.

Animals↗

PubMed1982

Serial changes in pulmonary functions in children hospitalized with cystic fibrosis.

Pulmonary functions were serially measured in 17 children hospitalized with cystic fibrosis (CF) to determine how much and when pulmonary functions improved during 14 days of inpatient treatment. Absolute lung volumes and forced expiratory flows were recorded every other day while patients received chest physiotherapy, antibiotics, and bronchodilators. Vital capacity first improved after the fifth hospital day coincidentally with a reduction in residual volume and an increase in peak expiratory flow rate. Significant improvements in other pulmonary functions developed later in the hospitalization. Improvement in most pulmonary functions continued throughout the hospitalization and was maintained 2 wk after discharge. Improvement was less and uniformly developed later in those children with severe lung disease on admission (NIH score less than 50) compared with those with moderate respiratory involvement (NIH score greater than 50). Pulmonary function measurements may prove useful in determining the optimal duration of treatment for patients who are hospitalized with CF.

Adolescent↗

PubMed1979

Partial obstruction of endotracheal tubes in children: incidence, etiology, significance.

We examined 99 endotracheal tubes removed from 81 pediatric patients to determine the incidence of partial endotracheal tube obstruction and predisposing factors. The overall incidence of obstruction was 20.2% (20/99); 14 of the 20 obstructed tubes were occluded less than 50%. General anesthesia during the period of intubation was the only factor significantly associated with an increased incidence of obstruction (p less than 0.05). There was no correlation of obstruction with duration of intubation, the presence of a Murphy-eye side hole, or small tube size. Among the 71 tubes from patients who received general anesthesia, a tube size of 4 mm or less was associated with an increased incidence of obstruction (p less than 0.05). Pressure-flow curves for three different sizes of endotracheal tubes were constructed to determine the increase in resistance produced by different degrees of obstruction. At flow rates that approximated those found in children during quiet breathing, the resistance of tubes that were 50% obstructed was 4 times greater than that found in unobstructed tubes.

Adolescent↗

PubMedDate not supplied

Differences in asthma prevalence between samples of American Indian and Alaska Native children.

OBJECTIVES: To better understand the prevalence of asthma among American Indian and Alaska Native (AI/AN) children and to explore the contribution of locale to asthma symptoms and diagnostic assignment, the authors surveyed AI/AN middle school students, comparing responses from metropolitan Tacoma, Washington (metro WA) and a non-metropolitan area of Alaska (non-metro AK). METHODS: Students in grades 6-9 completed an asthma screening survey. The authors compared self-reported rates of asthma symptoms, asthma diagnoses, and health care utilization for 147 children ages 11-16 self-reporting as AI/AN in metro WA and 365 in non-metro AK. RESULTS: The prevalences of self-reported asthma symptoms were similar for the metro WA and non-metro AK populations, but a significantly higher percentage of metro WA than of non-metro AK respondents reported having received a physician diagnosis of asthma (OR 2.33; 95% CI 1.23, 4.39). The percentages of respondents who reported having visited a medical provider for asthma-like symptoms in the previous year did not differ. CONCLUSIONS: The difference in rates of asthma diagnosis despite similar rates of asthma symptoms and respiratory-related medical visits may reflect differences in respiratory disease patterns, diagnostic labeling practices, or environmental factors. Future attempts to describe asthma prevalence should consider the potential contribution of non-biologic factors such as diagnostic practices.

Adolescent↗