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Biomedical subjects

I B Masters

Publications and source records attributed to I B Masters.

At least 37 records · Page 2Linked to original sources
PubMed2000

Severe obstructive sleep apnoea secondary to pressure garments used in the treatment of hypertrophic burn scars.

Obstructive sleep apnoea (OSA) secondary to pressure garments used to treat hypertrophic scarring of burns has never been reported. The present study describes two children who presented with OSA following introduction of such garments for management of hypertrophic scars following severe facial and upper body burns. Complex sleep polysomnography confirmed severe OSA with desaturations sufficient to result in physiological dysfunction that significantly improved on removal of the garments. As there is little evidence to suggest that the use of such garments alters the end result, the potentially serious side effect of obstructive sleep apnoea should be considered before their use is advised.

Adolescent↗
PubMed2000

Asthma management in indigenous children of a remote community using an indigenous health model.

OBJECTIVE: To describe the management of asthma in children in a remote indigenous community and the delivery of subspecialist service through the indigenous health-care model. METHODOLOGY: Children referred by indigenous health-care workers were evaluated prospectively by paediatric respiratory physicians, based on a standardized protocol, at a primary health care setting at Thursday Island, Queensland. RESULTS: Forty of the 54 children referred with a provisional diagnosis of asthma did have asthma, with 30% having persistent asthma. Only 59% of parents knew the dose of the medication prescribed and 80% had minimal knowledge of the medications. In 88% of children, the management of asthma was improved by introduction of an appropriate spacer device and changing the dose and type of medications. CONCLUSIONS: The management of children with asthma in the Torres region can be improved substantially by the use of age appropriate delivery devices and medications, and improving knowledge of asthma. Specialist delivery service to remote indigenous communities can be effectively delivered in partnership with the indigenous health service. The high proportion of persistent asthma in the Torres Straits community in comparison to urbanised Australia raises issues of inequity of appropriate medical service delivery to remote indigenous communities.

Adolescent↗
PubMed1999

Clinical versus polysomnographic profiles in children with obstructive sleep apnoea.

OBJECTIVE: To examine the clinical and polysomnographic (PSG) profiles of neurologically normal and abnormal children with obstructive sleep apnoea (OSA) and explore the relationship between these profiles. METHODOLOGY: We enrolled 56 children with persistent snoring and OSA for the study, 16 of whom were neurologically abnormal. All children were examined clinically and attended an overnight PSG study. Total clinical scores, PSG scores, and mild/moderate or severe ratings were derived for each child. RESULTS: Comparison of individual PSG parameters with neurological status demonstrated that the abnormal children had significantly increased obstructive apnoea indices, increased desaturation events and lower mean arousal indices compared to their neurologically normal OSA peers. For the neurologically abnormal children, there was a significant correlation between severity ratings of disease according to clinical and PSG profiles (r = 0.56, P = 0.03, sensitivity 82%) using the clinical summary as the gold standard, although the association was less marked in the neurologically normal children (r = -0.08, P = NS, sensitivity 69%). CONCLUSION: Neurologically abnormal children are likely to have more severe abnormalities in selected polysomnographic indices and overall scores. However, the clinical assessment is only likely to reflect this at the severe end of the spectrum. These relationships are not seen in the neurologically normal child, where little or no reliance can be placed upon predicting the severity of the polysomnographic findings from the clinical data. Decisions regarding the severity of disease and treatment should be based on the combined findings of the clinical and PSG data rather than overall clinical and polysomnographic scores or selected clinical and polysomnographic parameters.

Arousal↗
PubMed1999

Awake daytime oximetry measurements in the management of infants with chronic lung disease.

OBJECTIVE: To assess the value of 1-h daytime awake oximetry as a means of weaning oxygen flows in infants with oxygen dependent chronic lung disease. METHODS: A cohort study of oxygen dependent infants enrolled in a 3-month period. One hour of awake oximetry data were compared with equal time periods defined within a polysomnographic study and at the same oxygen flow rate. Sensitivity results were derived from the decision to wean oxygen to a lower flow or air. RESULTS: Twenty-two infants were enrolled and 27 studies were performed. The infants that could be weaned had an awake median of mean oxygen saturations of 97% and spent 14% of the time < or = 95% but only 2% < or = 92%, while for those not weaned, the awake median of mean oxygen saturations was 94% with 43% of their time < or = 95% and 26.8% < or = 92% saturation. CONCLUSIONS: Daytime oximetry can predict the outcome of polysomnography with a sensitivity of 100% and a specificity of 65%, and could be used to wean oxygen or as a screening tool for polysomnographic studies in infants with chronic lung disease provided there are reasonably long periods of monitoring and mean oxygen saturations above 95%.

Bronchopulmonary Dysplasia↗
PubMed1999

Six-month follow-up of children with obstructive sleep apnoea.

OBJECTIVES: This study examined prospectively changes in development, temperament and sleep related behaviour in children referred for obstructive sleep apnoea (OSA) and polysomnographic sleep study, some of whom had surgical intervention. METHODOLOGY: Using a prospective cohort study design, parents of 56 children referred for OSA completed sleep and temperament questionnaires and their child was assessed developmentally at the time of the polysomnographic sleep study. Forty (72%) of the children were neurologically normal. At 6 months, 42 children were reassessed using sleep and temperament questionnaires and a developmental assessment. After excluding the primary snorers, subjects were categorised as having had intervention (n = 24) or not (n = 15), and differences over the 6-month period in Griffiths scores, temperament and sleep related behaviour were examined. RESULTS: Regardless of intervention status, there was an improvement in night-time and day-time sleep behaviour for the total group, though the extent of improvement was more marked in the intervention group. For the neurologically normal children, improvement in the sleep behaviour was only significant for the intervention group (P < 0.05). Intervention did not result in any significant changes in Griffiths developmental score or temperament. CONCLUSION: Surgical intervention improves sleep behaviour in children though not temperament or development.

Adenoidectomy↗
PubMed1999

Aetiological factors and development in subjects with obstructive sleep apnoea.

OBJECTIVE: To examine whether maternal pregnancy complications, adverse birth events, respiratory illnesses, or developmental difficulty were increased in neurologically normal children with obstructive sleep apnoea (OSA) and whether severity of OSA adversely affects the child's development and temperament. METHODOLOGY: Maternal report of perinatal events, respiratory illness and developmental difficulty in 37 children with OSA was contrasted with a comparison group (n = 67). Children with OSA were assessed developmentally (Griffiths Scales), had a parental rating of temperament (Australian Temperament Scale) and attended an overnight polysomnographic sleep study. RESULTS: Children with OSA had an increased prevalence of adverse maternal pregnancy and perinatal events, respiratory disease and developmental concerns. Limited associations were found between the severity of OSA and development or temperament difficulty. CONCLUSIONS: This study suggests a relationship between OSA, though not its severity, and pre/perinatal adversity and child development. Polysomnographic and detailed developmental assessment of community-based samples of children with OSA and control children are necessary to confirm these findings.

Australia↗
PubMed1999

Modified nasopharyngeal tube for upper airway obstruction.

A modified nasopharyngeal tube is described that does not add airway dead space and resistance, is well tolerated, highly successful, and allows simultaneous use of oxygen prongs. This potentially reduces the need for surgical intervention to relieve high upper airway obstruction from Pierre-Robin syndrome and other causes.

Airway Obstruction↗
PubMed1998

Educating young children about asthma: comparing the effectiveness of a developmentally appropriate asthma education video tape and picture book.

Asthma self-management programmes have been shown to increase children's knowledge about asthma and improve their management practices and health status. However, existing programmes have rarely addressed the unique learning needs of very young children. This study aimed to develop and assess the effectiveness of a video tape and picture book designed to teach children about the prevention and management of acute episodes of asthma. The information content of the educational resources was determined by analysis of relevant medical information and asthma management skills. Social Learning Theory and consideration of the developmental stage of the target population informed the format and style of presentation of the resources. Eighty children aged between 2 and 5 years who had been diagnosed with asthma by their medical practitioner and who required daily asthma medication participated in a controlled experimental study. The study evaluated the impact of the asthma education resources on children's knowledge about asthma, compliance with medication regimens and health status. Children were randomly allocated to one of three experimental groups. Children in these groups were exposed to either the video tape alone, the book alone or both the video tape and book, or to a control group who viewed materials unrelated to asthma. The results for the three experimental groups were compared with the control group who did not receive exposure to any of the asthma education resources. The results showed that children in each experimental group had significantly greater gains in asthma-related knowledge than children in the control group and children exposed to both resources showed the greatest increases in knowledge. Children in each of the three experimental groups also had better compliance and health than children in the control group. These findings indicate that carefully designed asthma education resources are useful for providing even the youngest children with information about asthma and its management.

Asthma↗
PubMed1998

Measuring tidal volume and functional residual capacity change in sleeping infants using a volume displacement plethysmograph.

The noninvasive measurement of infant lung function during unsedated sleep in infants has been a long-standing objective in paediatric respiratory medicine. This note reports on the design and performance of a head-out volume-displacement plethysmograph (VDP) that overcomes some of the limitations of traditional lung function apparatus. The VDP comprises a rigid acrylic box with an integral water-sealed spirometer and a novel neck seal. The bilayer neck seal is of variable compliance and is comfortable and simple to use. The spirometer permits volume resolution of 1.5 mL and a dynamic range in excess of 100 mL. The frequency response extends from 0-7 Hz. Spirometer inertance was measured as 0.0015 kPa.L(-1).s(-2), resistance 0.021 kPa.L(-1).s(-1) and box capacitance 0.18L.kPa(-1). Tidal volume, respiratory rate and changes in functional residual capacity can be recorded during unsedated rapid eye movement and nonrapid eye movement whilst monitoring with conventional polysomnographic methods. The head-out configuration allows additional instrumentation to be implemented with ease, avoids facial stimulation and allows unimpeded access to the upper airway. A polysomnograph illustrating the limitations of respiratory inductance plethysmography signals and typical changes in functional residual capacity are shown.

Functional Residual Capacity↗
PubMed1997

Abnormalities in surfactant in sudden infant death syndrome as a postmortem marker and possible test of risk.

OBJECTIVE: To determine whether physical abnormalities in lung surfactant, particularly inversion of the hysteresis between surface tension and surface area, are an effective postmortem marker for sudden infant death syndrome (SIDS). METHODOLOGY: Bronchoalveolar lavage (BAL) was employed to obtain lung rinsings from 55 infants under 24 months of age at autopsy, comprising 34 index cases and 21 controls. Folch reagent was used to extract the lipoid content which was then applied at two surface concentrations, fixed and BAL-determined (BALD), to the pool of a Langmuir trough in which surface tension (gamma) was measured continuously by the Wilhelmy method as surface area (A) was cycled. RESULTS: The gamma:A loops from SIDS samples were inverted relative to controls (i.e. they were hysteresis reversed, this inversion being quantified by an empirical surface tension: area reversal (STAR) score). There was a wide scatter of STAR scores, but a critical value was found which offered a significant (P = 0.017) separation of SIDS cases from controls for a fixed surface concentration and a highly significant separation (P = 1.0 x 10(-4)) for BALD surface concentrations. Differences in the yields of phospholipid and proteolipid, or their correlation to STAR scores, did not reach statistical significance. CONCLUSIONS: Inversion of the gamma :A loops (i.e. hysteresis inversion) would appear to offer a better postmortem marker of SIDS than any reported previously, the procedure having potential for development as a prospective test indicating the risk of this disease.

Autopsy↗
PubMed1997

Raised bile acid concentrations in SIDS lungs at necropsy.

Previous studies of the abnormal physical properties of lung surfactant derived from infants experiencing prolonged expiratory apnoea, or who have died of sudden infant death syndrome (SIDS), have led to a search for the agent responsible. Bronchoalveolar lavage (BAL) has been performed upon 12 infants under 12 months at necropsy and the rinsings analysed for up to 26 bile acids using high performance liquid chromatography, which requires nanomolar quantities. They were also analysed for simultaneously retrieved phospholipid and proteolipid-a minor component of lung surfactant-as markers of lavage efficiency. Total bile acid (TBA) was found to be higher in six SIDS cases, reaching a mean (SE) 8.54 (2.24) mumol/l in the BAL fluid compared with 4.66 (1.47) mumol/l in the six controls of similar age. When related to the concomitant surfactant yield, the TBA/ proteolipid and TBA/phospholipid ratios both showed highly significant differences between index lungs and controls, providing another postmortem marker of SIDS with potential for development as a test of risk. Since the bile:phospholipid ratio determines whether phospholipase A2 synthesises or hydrolyses phospholipid, the raised TBA/phospholipid ratio could be highly significant, causing this enzyme to function more like its role in the gut than in the lung.

Autopsy↗
PubMed1995

A novel role for surfactant in the lung with implications for the sudden infant death syndrome.

Feedback from mechanoreceptors in the lungs to the brainstem has long been known to be vital for control of rhythmogenesis during normal breathing. Action potentials transmitted via the vagi are shown to display an irreversible relationship with respect to lung area (A), i.e. hysteresis, which closely resembles the hysteresis in surface tension (gamma) versus A for normal surfactant which coats that surface. Since lung recoil is largely determined by surface tension for resting tidal volumes, this will dominate the stretch of mechanoreceptors. Hence, it is postulated that, through the Hering-Breuer reflex, surfactant largely determines afferent neural feedback, explaining the above similarity in clockwise hysteresis loops. Thus the ability of normal surfactant to impart normal clockwise gamma: A hysteresis is seen as a desirable property enabling the brainstem to differentiate between the inspiratory and expiratory phases of the breathing cycle at the same lung volume. It is further hypothesized that the very abnormal surfactant found recently in some infants with prolonged expiratory apnoea by displaying anti-clockwise gamma: A loops would render afferent neural feedback to the brainstem highly confusing and could cause prolonged expiratory apnoea. This concept is discussed as a possible cause of sleep apnoea, recurrent cyanotic episodes and the Sudden Infant Death Syndrome (SIDS).

Brain Stem↗
PubMed1994

Age-related changes in oxygen saturation over the first year of life: a longitudinal study.

Stability of oxygen saturation depends on maturation and function of individual components of the respiratory system. The aim of this study was to record and analyse comprehensive oxygen saturation data in a longitudinal study over the first year of life. Detailed sleep studies were performed on 15 normal infants eight times in the first year of life. The accrued oxygen saturation data were analysed on a computerized oximetry data analysis system. Results show the mean sleep saturation levels trending upwards and stabilizing by 185 days. There was an inverse curvilinear relationship between mean age and median desaturation time and the median number of desaturations at < or = 95, < or = 92 and < or = 90% saturation. The mean cumulative desaturation time < or = 90% in the first 4 months was 11.08 min (range 2.5-36.57 min). This study demonstrates monotonic patterns of increasing saturation and decreasing number and time of desaturations < or = 95% and < or = 90% but a random pattern of desaturations < or = 85% occurs across the first 6 months of life. Cumulative desaturation times over the first 4 months of life were high and could be important to the development of maturity of the respiratory system. After 6 months, all indices of saturation and desaturation point to a stable and mature respiratory system.

Aging↗