Biomedical subjects

N J Freezer

Publications and source records attributed to N J Freezer.

6 recordsLinked to original sources

PubMed1995

Obstructive sleep apnoea presenting as failure to thrive in infancy.

OBJECTIVE: To study the postoperative outcome of infants under the age of 18 months in whom an adenotonsillectomy had been performed, with particular emphasis on the pre- and postoperative weight gain and linear growth velocities, and the resolution of symptoms of obstructive sleep apnoea (OSA). METHODOLOGY: A retrospective study of all infants in whom an adenotonsillectomy had been performed during the 5 year period to January 1990. Details of pre- and postoperative outcome variables were obtained by review of hospital and office records and by telephone calls to the parents. RESULTS: Complete data were available for 29 (76%) of the 38 infants in whom an adenotonsillectomy had been performed. The data from these infants are reported. Pre-operatively, all infants had clinical symptoms of OSA, and 52% of infants also presented with failure to thrive (FTT). Seven infants were dysmorphic: three had Down syndrome, three had a craniofacial anomaly and one infant had Mobius syndrome. Following adenotonsillectomy, 23 infants (79%) had complete resolution of their OSA symptoms. Two infants with Down syndrome required a tracheostomy to relieve persistent upper airway obstruction. Eighty-seven per cent of the infants with pre-operative FTT had a significant increase in weight gain velocity postoperatively (mean 195.1 +/- 80.8 s.d. vs 509.8 +/- 249.1 g/month; P < 0.001), including the infants with mild persistent symptoms of OSA. The weight gain velocity of infants who were not failing to thrive pre-operatively did not change significantly following adenotonsillectomy (328.1 +/- 106.9 vs 333.2 +/- 146.4 g/month; P = 0.82). The linear growth velocity of all infants did not change significantly postoperatively. CONCLUSIONS: OSA should be considered in infants with FTT, as adenotonsillectomy is an effective treatment for OSA in infancy, and the weight gain velocity of these infants may increase significantly postoperatively. Overnight oximetry or other physiological studies may be required if the clinical signs and symptoms of OSA are equivocal.

Adenoidectomy↗

PubMed1995

Growth of prepubertal children with mild asthma treated with inhaled beclomethasone dipropionate.

Poorly controlled severe asthma can lead to growth impairment in childhood. In children with mild asthma, it is less clear whether treatment influences growth or adrenal function. We determined in a randomized, double-blind, placebo-controlled, community-based study, the effect of inhaled beclomethasone dipropionate (BDP) 400 micrograms/day for 7 mo on the linear growth and adrenal function of 94 children 7 to 9 yr of age. Height was measured at least monthly during treatment, and adrenal function assessed by overnight urinary cortisol at baseline and after 3 and 6 mo of treatment. Mean regressed daily growth was significantly decreased during the treatment period in the BDP-treated group, 0.79 versus 1.14 mm/wk (difference 0.35 mm/wk; 95% CI -0.46 to -0.25; p < 0.0001). At the end of the 7 mo, the BDP-treated children had grown significantly less than the children on placebo: mean of 2.66 versus 3.66 cm (difference 1.0 cm; 95% CI -1.36 to -0.64 cm; p < 0.0001). Growth was significantly decreased in both males and females. During a washout period of 4 mo, there was no significant catch-up growth. BDP had no effect on overnight urinary cortisol production. BDP at a dose taken by many children significantly decreases statural growth in children with mild asthma, and this effect is unlikely to be mediated through the hypothalamo-pituitary-adrenal axis.

Administration, Inhalation↗

PubMed1995

Prostaglandin D2-induced bronchoconstriction is mediated only in part by the thromboxane prostanoid receptor.

Prostaglandin D2 (PGD2) is a potent bronchoconstrictor, and is thought to have a role in the pathogenesis of asthma. PGD2 causes vasodilation acting via the prostaglandin (DP) receptor on vascular smooth muscle, and myocontraction acting via the thromboxane (TP) receptor on bronchial smooth muscle. To determine the relative contribution of these mechanisms we have studied the degree to which a potent TP receptor antagonist inhibits PGD2-induced bronchoconstriction. Twelve atopic asthmatic subjects underwent baseline PGD2 bronchial challenges to determine the cumulative concentration of PGD2 required to reduce forced expiratory volume in one second (FEV1) by 20%. At four subsequent randomized visits, subjects received this concentration of PGD2 90 min after dosing with placebo or 20, 50 or 100 mg of BAY u 3405, a potent competitive TP receptor antagonist. Serum was taken for drug assay at 90 min. After each dose of PGD2, FEV1 was measured for 30 min, and the area under the percentage fall in the FEV1/time curve (AUC) was calculated. The mean +/- SEM AUC for placebo was 414 +/- 68, and for the 20, 50 and 100 mg doses of BAY u 3405 was 169 +/- 33, 173 +/- 59 and 135 +/- 63, respectively. There were no significant differences between the AUCs for any of the drug doses, whilst all three doses were significantly different from placebo. The plateau response achieved with increasing doses of the antagonist suggests complete blockade of the TP receptor. These data demonstrate that thromboxane receptor blockade only partially inhibits the airway narrowing response to PGD2, and support the existence of a vascular component to PGD2-induced acute airway narrowing in asthma.

Adult↗

PubMed1991

Pulmonary mechanics and outcome of neonates on ECMO.

Deciding when to wean neonates from extracorporal membrane oxygenation (ECMO) can be difficult. The usefulness of simple measurements of pulmonary mechanics e.g., dynamic compliance (Cdyn) has been questioned. We investigated the pulmonary mechanics of eight neonates using the interrupter technique, which allows the partitioning of pulmonary mechanics into compartments representing the conducting airways and more peripheral phenomena (viscoelastic properties and "pendelluft"). Three neonates required ECMO for a congenital diaphragmatic hernia (CDH), two for hyaline membrane disease (HMO), two for meconium aspiration syndrome (MAS), and one for pneumonia. All neonates with MAS, HMD, and pneumonia were successfully weaned from ECMO when their Cdyn was 0.3 mL/cmH2O/kg or greater [mean 0.34 +/- 0.06 (SEM)]. All three neonates with CDH died and their highest Cdyn was 0.21, 0.19, and 0.09 mL/cmH2O/kg respectively (mean, 0.16 +/- 0.037). The airway resistance (Raw) and the slower component of pressure change after interruption (delta Pdiff), a measure of the more peripheral phenomena of the lung, were not significantly different in those neonates who survived and those who did not. The values for delta Pdiff in all patients were higher than those in healthy neonates. However, the Raw was not different. This suggests that the major disturbance in pulmonary mechanics was distal to the conducting airways. Those neonates who were successfully weaned from ECMO had a significantly higher Cdyn 24-48 hours prior to decannulation. Considering the lung as a two-compartment model offers no advantages when compared to the one-compartment model for the prediction of the outcome of a neonate on ECMO.

Airway Resistance↗

PubMed1990

Tracheostomy in children with Guillain Barré syndrome.

During the 10-yr period beginning January 1979, 59 infants and children with Guillain Barré syndrome (GBS) were admitted to our hospital. Tracheostomies were performed in 15 patients and their records were reviewed. Fourteen patients were recalled for assessment of pulmonary function and respiratory muscle strength (RMS). The median duration of assisted ventilation (including endotracheal [ET] intubation) was 21 days and the median duration of tracheostomy was 39 days. Only two patients were discharged with the tracheostomy in situ. All patients were successfully decannulated at the first attempt. No tracheostomy-related complications or symptoms were reported apart from croup in two patients. On review, lung volumes and maximal inspiratory and expiratory flows were normal. There was no evidence of tracheal stenosis or significant tracheomalacia. RMS tests were normal. In this hospital, tracheostomy is a safe, well-tolerated procedure in the management of infants and children with GBS who need long-term ventilation. There were no deaths and all patients returned to their normal school or were gainfully employed after their illness, although 12 patients had mild persistent weakness of at least foot dorsiflexion.

Adolescent↗

PubMed1990

Tracheostomy.

The records of all children who had a tracheostomy performed over a 10 year period from January 1979 were reviewed. Altogether 142 patients aged 1 day to 24.8 years received a tracheostomy, 70 in the first year of life. The conditions necessitating tracheostomy were trauma (n = 21), acquired subglottic stenosis (n = 21), subglottic haemangioma (n = 16), Guillain-Barré syndrome (n = 14), Pierre Robin syndrome (n = 9), craniofacial disorders (n = 9), micrognathia (n = 5), and others in 47. In patients successfully decannulated the median period of tracheostomy was 104 days (range 3 days to 9.0 years) and in 25 patients the tracheostomy is still in situ. Eighty four patients (60%) were discharged from hospital with their tracheostomy in situ and no patient was kept in hospital because of a tracheostomy beyond four weeks. There were two tracheostomy related deaths in hospital. Both patients had severe acquired subglottic stenosis secondary to ventilation for lung disease of prematurity. There were no tracheostomy related deaths at home; complications included tracheal granulomas and polyps (n = 19). After removal of the tracheostomy 13 children had a fistula requiring surgical closure and four required revision of the tracheostomy scar. Tracheostomy is well tolerated in small children, with few complications and can be managed safely in the home by the family.

Adolescent↗