Biomedical subjects

N Freezer

Publications and source records attributed to N Freezer.

9 recordsLinked to original sources

PubMed2006

Bronchiectasis.

Bronchiectasis is generally classified into cystic fibrosis and non-cystic fibrosis bronchiectasis. This review article describes non-cystic fibrosis bronchiectasis in adults. Bronchiectasis can be considered a heterogeneous condition characterized by irreversible airway dilatation with chronic bronchial infection/inflammation. It remains a common condition and is a major cause of respiratory morbidity. Many factors are associated with bronchiectasis, but most commonly patients will have idiopathic disease. Important clinical findings include chronic productive cough, rhinosinusitis, fatigue and bi-basal crackles. Patients have usually had symptoms for many years. Diagnosis is confirmed by high-resolution computed tomography scanning using standardized criteria. Spirometry shows moderate airflow obstruction and there is a high prevalence of bronchial hyperreactivity. The most common pathogens are non-typeable Haemophilus influenzae and Pseudomonas aeruginosa. There may be considerable overlap with other chronic airway diseases. Treatment regimens are still not well defined. Patients tend to have ongoing symptoms and decline in respiratory function despite treatment.

Bronchiectasis↗

PubMed2005

Encasement of bedding does not improve asthma in atopic adult asthmatics.

AIM: We evaluated the impact of impermeable bed covers on asthma in asthmatics with clinically relevant house dust mite (HDM) sensitization. METHODS: The study included 32 HDM-sensitized asthmatics in whom HDM allergy was considered as a significant factor in their asthma. They were randomized into either an intervention group whose bedding was encased with impermeable covers, or a control group who received cotton covers. Before and 3 and 6 months after encasement, dust samples were collected from the bedding and assayed for Der p 1. Clinical outcomes included quality of life, lung function, bronchial reactivity to methacholine, symptoms, medications and peak flow rates. RESULTS: Baseline Der p 1 levels in both the active and the placebo groups were comparable and high (19.2 vs 18.9 microg/g of dust). There was a significant reduction in Der p 1 levels in the active group after 6 months, but not in the placebo group (7.3 vs 21.9 microg/g of dust). Quality of life improved significantly in both the intervention and control groups, but there was no significant difference in the improvements between the groups. There was no significant change in lung function, symptoms, and requirements for medications. CONCLUSIONS: Encasement of bedding significantly reduced the Der p 1 levels. However, this was not sufficient to produce worthwhile clinical improvement in those in whom dust mite avoidance might well have been recommended as part of their clinical management.

Adult↗

PubMed2003

Adrenal suppression from high-dose inhaled fluticasone propionate in children with asthma.

This cross-sectional study was designed to examine the prevalence of adrenocortical suppression in children with asthma treated with high-dose inhaled fluticasone propionate (FP). Children and adolescents (n=50) with asthma, treated with inhaled FP at a dose of > or = 1,000 mg a day for > or = 6 months, were enrolled. Early morning serum cortisol was performed. Subjects with a serum cortisol of < 400 nmol x L(-1) had a tetracosactrin stimulation test. Fifty subjects of mean age 13.1 yrs were treated with a mean dose of 924.7 microg x m(-2) x day(-1) FP for a mean duration of 2 yrs. Of the 50 subjects, 36 (72%) had serum cortisol levels of < 400 nmol x L(-1) and underwent tetracosactrin stimulation test. Of these, 6 (17%) demonstrated a less than two-fold increase in serum cortisol from baseline and peak cortisol level of < or = 550 nmol x L(-1) at 30 or 60 min poststimulation. There was a significant negative correlation between the dose of FP x m(-2) and stimulated peak cortisol level. Biochemical evidence of adrenocortical insufficiency was demonstrated in 12% of the subjects, indicating that high-dose fluticasone propionate use may be associated with dose-dependent adrenocortical suppression.

Administration, Inhalation↗

PubMed2001

Diagnostic value and pathophysiologic basis of pulsus paradoxus in infants and children with respiratory disease.

The purpose of the study was to analyze the respiratory-dependent intraarterial blood pressure variations (pulsus paradoxus, PP) in intensive care unit patients with obstructive and restrictive pulmonary disease, and to evaluate the usefulness of PP for assessment of disease severity. One-minute paper recordings of arterial blood pressures, left atrial pressures (LAP, 16 patients), breathing cycles, and electrocardiograms (ECG) were taken in 54 nonintubated children. There was a close relationship between systolic and diastolic blood pressure variations (r = 0.92). The mean coefficient of variation of PP was 18.4% (SD 11.6%). The relationship between respiratory dependent LAP fluctuations (Delta LAP) and PP was logarithmic. PP correlated significantly with a respiratory severity score (RSS: wheeze, oxygen requirement, heart rate, arterial partial pressure of carbon dioxide) in a subgroup of 16 asthmatics (r = 0.66, P = 0.005); wheeze score was the only true independent determinant of RSS (multiple regression). In the nonasthmatics with restrictive lung disease, the correlation coefficient for the association between PP and RSS was 0.34 (P = 0.08), with a significant univariate correlation between PP and wheeze score (r = 0.62, P = 0.001). We conclude that PP correlates significantly with wheeze in obstructive and restrictive disease. PP is a valuable clinical sign of disease severity in patients with wheeze as clinical manifestation of obstructive airway disease. The relationship between Delta LAP and PP confirms the finding that an increase in PP is associated with a rise in left atrial transmural pressure.

Adolescent↗

PubMed2001

Nasopharyngeal oxygen therapy produces positive end-expiratory pressure in infants.

UNLABELLED: The World Health Organisation recommends nasopharyngeal catheters as a safe and efficient method of oxygen administration in infants. However, little is known about the mechanisms of the improvement in oxygenation. The aim of the present study was to determine whether nasopharyngeal oxygen therapy produces positive end-expiratory pressure (PEEP). Nine spontaneously breathing infants (median age 13 months, range 10 days to 20 months) after heart surgery were investigated. All patients had normal pulmonary blood flow at the time of the study (Qp:Qs=1:1). Oxygen (oxygen fraction 1.0) was delivered by an 8 F catheter inserted into the nasopharynx (tip just visible below the soft palate). The pulmonary mechanics were analysed using a single compartment model of the respiratory system. Oesophageal pressure (Pes) at end-expiration, dynamic lung compliance (C(L)) and resistance (R(L)), minute ventilation, PaCO2 and PaO2 were measured at baseline without a nasopharyngeal catheter or oxygen, and at oxygen flows of 0.5 l/min, 1.0 l/min and 2.0 l/min. All the flows generated significant increases in PEEP. Mean difference in PEEP (SD, paired t-test versus baseline): 1.6 cm H2O (1.4, P=0.008) with 0.5 l/min of oxygen; 2.8 cm H2O (2.7, P=0.014) with 1.0 l/min of oxygen; and 4.0 cm H2O (2.9, P = 0.004) with 2.0 l/min of oxygen. There was a significant correlation between all the nasopharyngeal flows (in ml/kg per min) and the generated PEEP (P<0.001) and between the C(L) values and the generated PEEP (P < 0.05). There was no significant difference in PaCO2 and R(L). Minute ventilation was significantly less with nasopharyngeal oxygen than at baseline. As expected, PaO2 increased significantly with increasing oxygen flows. CONCLUSION: Administration of oxygen through an 8 F nasopharyngeal catheter at flow rates recommended by the World Health Organisation (0.5 l/min in newborns, 1.0 l/min in infants) produces moderate amounts of positive end-expiratory pressure. The levels achieved may contribute to an improvement in oxygenation by altering the visco-elastic properties of the lung.

Female↗

PubMed2001

Bone mineral density in prepubertal asthmatics receiving corticosteroid treatment.

OBJECTIVE: To examine whether bone mass is reduced in prepubertal, asthmatics receiving high doses of inhaled corticosteroids. METHODOLOGY: A cross-sectional comparison of lumbar spine-bone mineral density (LS-BMD) was undertaken in 76 subjects after stratifying them according to dosage and administration route of corticosteroid. RESULTS: Weight was the only independent predictor of LS-BMD (r(2) = 0.38). Children receiving greater than 800 microg/day of inhaled corticosteroid plus intermittent oral corticosteroid had a significantly lower weight-adjusted LS-BMD than children treated with 400-800 microg/day of inhaled corticosteroid (mean difference: 0.06 g/cm(2), 95% confidence interval (CI): - 0.02 to - 0.10). A significant difference in weight-adjusted LS-BMD persisted when all children receiving greater than 800 microg/day of inhaled corticosteroid, irrespective of additional oral corticosteroid treatment, were compared with children receiving 400-800 microg/day of inhaled corticosteroid (mean difference: - 0.05 g/cm(2), 95%CI interval: -0.02 to - 0.09). Bone mass was similar in children not receiving any inhaled corticosteroid and those treated with 400-800 microg/day of inhaled corticosteroid. CONCLUSIONS: A reduced bone mass in prepubertal asthmatic children receiving high doses of inhaled corticosteroids may predetermine a compromised peak bone mass and increase osteoporotic fracture risk in adulthood.

Absorptiometry, Photon↗

PubMed1996

Osteocalcin, growth, and inhaled corticosteroids: a prospective study.

OBJECTIVES: To determine the relationship between biochemical markers of bone metabolism and statural growth, and their suitability as surrogate markers of inhaled corticosteroid induced growth suppression. DESIGN: Randomised, double blind, placebo controlled comparison of inhaled beclomethasone dipropionate 200 micrograms twice daily as dry powder for six months. SETTING: Southampton. OUTCOME MEASURES: Serum osteocalcin, urinary deoxypyridinoline, and statural growth. SUBJECTS: 7 to 9 year old children with recurrent wheeze. RESULTS: There were no significant differences in serum osteocalcin between the beclomethasone dipropionate and placebo group measured at baseline or after three and six months' treatment, while deoxy-pyridinoline was significantly higher in the placebo treated children after three months. Growth was significantly decreased in the beclomethasone dipropionate group over the course of the study. Growth over the six months, both in those receiving beclomethasone dipropionate and those receiving placebo, was significantly correlated with serum osteocalcin measured at three months and six months. CONCLUSION: Although serum osteocalcin shows excellent correlation with growth, it is a poor marker for decreased growth associated with use of inhaled corticosteroids.

Administration, Inhalation↗

PubMed1991

Non-invasive determination of alveolar pressure during mechanical ventilation.

The development of inadvertent positive end-expiratory pressure (PEEPi) in ventilated infants is of clinical relevance and difficult to measure non-invasively. A method for estimating end-expiratory alveolar pressure by applying a multiple regression analysis to airway opening pressure, flow and volume recordings during mechanical ventilation was evaluated. In eight open-chested, paralysed and mechanically ventilated mongrel dogs, alveolar pressure was measured directly with "alveolar capsules". Alteration of ventilation patterns and addition of a resistive element were used in three dogs to induce different levels of PEEPi. End-expiratory alveolar pressure measured directly and determined from multilinear regression of airway opening pressure correlated well (mean error 0.06 +/- 0.53 (+/- SD) hPa, limits of agreement -1.16 to +1.04 hPa). The other five dogs received inhalation challenges, two with histamine, two with hypertonic saline and one with methacholine resulting in a mean increase of respiratory system resistance of 230% (range 141-489%) of the baseline values. The mean error in determining PEEPi was 0.54 +/- 0.37 hPa, the limits of agreement were -0.20 to 1.28 hPa. The method was then applied to seven mechanically-ventilated children (aged 2 months to 8 yrs, weight 4.9-23.5 kg) and the results were compared to the pressure at which inspiration began (equalling PEEPi). Seventy eight measurements were performed during open heart surgery, while compliance changed by between 3 and 186% of baseline values due to the surgical procedures. PEEPi estimated by multiple regression agreed well with the pressure at which inspiration began (mean difference 0.25 +/- 0.68 hPa, limits of agreement -1.12 to 1.62 hPa).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Steroids in croup: do they increase the incidence of successful extubation?

Between January 1983 and July 1988, 2623 patients with croup were admitted to the Royal Children's Hospital, Melbourne. A total of 416 patients (16%) were admitted to the Intensive Care Unit and 176 of these patients required intubation. Of these patients 117 patients were successfully extubated at the first attempt and 59 needed reintubation. Of the patients who were reintubated 35 were given steroids prior to subsequent extubation attempts. Only one patient who had received steroids failed extubation. Of those who did not receive steroids 59% required reintubation. In patients with croup who fail the first extubation the results of this study suggest that steroids significantly increase the success of subsequent extubations.

Adolescent↗