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Biomedical subjects

Gillian M Nixon

Publications and source records attributed to Gillian M Nixon.

13 recordsLinked to original sources
PubMed2006

Pulse intravenous methylprednisolone for resistant allergic bronchopulmonary aspergillosis in cystic fibrosis.

Allergic bronchopulmonary aspergillosis (ABPA) results from a hypersensitivity response to Aspergillus fumigatus. It is seen in a number of chronic respiratory conditions, particularly in association with cystic fibrosis (CF). Oral corticosteroids and itraconazole represent the mainstay of treatment. There is evidence for the use of pulse methylprednisolone in other respiratory conditions as well as a number of inflammatory conditions. This is the first reported use of pulse intravenous methylprednisolone in the treatment of ABPA in CF. We present the clinical course of four children with CF and severe ABPA, in whom pulse methyprednisolone was used to manage the disease because of relapses or marked side effects on high-dose oral corticosteroids. Methylprednisolone pulses achieved disease control in 3 of the 4 children. However, troublesome side effects were experienced, in some cases necessitating discontinuation of therapy. Pulse methylprednisolone may represent a treatment option for children with CF and ABPA, where ABPA fails to respond adequately to routine therapy.

Antifungal Agents↗
PubMed2005

Lower airway inflammation in infants with cystic fibrosis detected by newborn screening.

Controversy exists over whether the lower airway inflammation that characterizes cystic fibrosis (CF) is initiated primarily by the genetic defect. To determine if inflammation precedes infection, we examined bronchoalveolar lavage (BAL) fluid cytology, cytokines (interleukin (IL)-1beta, IL-4, IL-5, IL-6, IL-8, IL-10, and tumor necrosis factor-alpha), and free neutrophil elastase activity from 70 CF (aged 1.5-71 months) children detected by newborn screening and 19 (aged 2.0-48 months) controls with chronic stridor. CF subjects were selected and categorized as pristine (13 aged </= 6 months, lacking prior respiratory symptoms and exposure to antibiotics, and without respiratory pathogens on BAL), infected (42 with viruses or >/= 10(5) colony-forming units/ml of pathogenic bacteria in BAL), and uninfected (15 aged > 6 months, asymptomatic, not taking antibiotics at bronchoscopy, and free of pathogens in their BAL). To further resolve if inflammation develops without infection, inflammatory mediators in paired annual BAL samples from 38 CF subjects were measured, and results were grouped according to whether BAL showed persistence (n = 6), acquisition (n = 8), clearance (n = 13), or absence (n = 11) of infection. While pristine, uninfected, and control subjects had similar BAL profiles, infected patients showed elevated inflammatory indices, including increased IL-10 (P < 0.001). Pristine subjects had the fewest signs of inflammation. Analysis of BAL pairs found differences between the four infection groups for changes in neutrophil percentages, IL-8 (P < 0.001), and free neutrophil elastase (P = 0.009). Infection was associated with elevated inflammatory mediators in BAL fluid. In contrast, minimal or reduced signs of inflammation accompanied absence of eradication of infection from BAL fluid. We conclude that in CF, infection initiates and sustains airway inflammation.

Bronchoalveolar Lavage Fluid↗
PubMed2004

Planning adenotonsillectomy in children with obstructive sleep apnea: the role of overnight oximetry.

OBJECTIVE: Obstructive sleep apnea (OSA) in children is usually effectively treated by adenotonsillectomy (T&A). However, there may be a waiting list for T&A, and the procedure is associated with an increased risk of postoperative complications in children with OSA. Needed is a simple test that will facilitate logical prioritization of the T&A surgical list and help to predict children who are at highest risk of postoperative complications. The objective of this study was to develop and validate a severity scoring system for overnight oximetry and to evaluate the score as a tool to prioritize the T&A surgical list. METHODS: This study comprised 3 phases. In phase 1, a severity score was developed by review of preoperative overnight oximetry in children who had urgent T&A in 1999-2000. In phase 2, the score was validated retrospectively in 155 children who had polysomnography (PSG) before T&A in 1992-1998. In a phase 3, a 12-month prospective evaluation of a protocol based on the score was conducted. RESULTS: In phase 1, a 4-level severity score was developed on the basis of the number and the depth of desaturation events (normal to severely abnormal, categories 1-4). In phase 2, the McGill oximetry score correlated with severity of OSA by PSG criteria. In phase 3, a clinical management protocol was developed based on the score. Of 230 children tested, 179 (78%) had a normal/inconclusive oximetry (category 1) and went on to have PSG. Those with a positive oximetry (categories 2-4; 22%) had no additional sleep studies before T&A. Timing of T&A was based on oximetry score, leading to a significant reduction in waiting time for surgery for those with higher oximetry scores. Postoperative respiratory complications were more common with increasing oximetry score. CONCLUSIONS: Overnight pulse oximetry can be used to estimate the severity of OSA, to shorten the diagnostic and treatment process for those with more severe disease, and to aid clinicians in prioritization of T&A and planning perioperative care.

Adenoidectomy↗
PubMed2003

Urgent adenotonsillectomy: an analysis of risk factors associated with postoperative respiratory morbidity.

BACKGROUND: The aim of this study was to determine the frequency and type of respiratory complications after urgent adenotonsillectomy (study group) for comparison with a control group of children undergoing a sleep study and adenotonsillectomy for obstructive sleep apnea syndrome. A second aim was to assess risk factors predictive of respiratory complications after urgent adenotonsillectomy. METHODS: The perioperative course of children who underwent adenotonsillectomy between January 1, 1999, and March 31, 2001, was reviewed. Two groups of children were identified from two different databases: the hospital database for surgical procedures (the study group) and the sleep laboratory database (the control group). The retrospective chart review focused on the preoperative status (including an evaluation for obstructive sleep apnea), anesthetic management, and need for postoperative respiratory interventions. RESULTS: A total of 64 consecutive cases for urgent adenotonsillectomy were identified, and 54 children met the inclusion criteria. Thirty-three children (60%) had postoperative respiratory complications necessitating a medical intervention; 11 (20.3%) required a major intervention (reintubation, ventilation, and/or administration of racemic epinephrine or Ventolin), and 22 (40.7%) required a minor intervention (oxygen administration). Six children (11.1%) required reintubation in the recovery room for respiratory compromise. Risk factors for respiratory complications were an associated medical condition (odds ratio, 8.15; 95% confidence interval, 1.81-36.73) and a preoperative saturation nadir less than 80% (odds ratio, 5.54; 95% confidence interval, 1.15-26.72). Sixteen (49%) of the medical interventions were required within the first postoperative hour. Atropine administration, at induction, decreased the risk of postoperative respiratory complications (odds ratio, 0.18; 95% confidence interval, 0.11-1.050. CONTROL GROUP: Of 75 children who underwent a sleep study and adenotonsillectomy, 44 had sleep apnea and were admitted to hospital after elective adenotonsillectomy. Sixteen (36.4%) children had postoperative respiratory complications necessitating a medical intervention. Six percent of the children (n = 3) required a major medical intervention. No child required reintubation for respiratory compromise. CONCLUSIONS: Severe obstructive sleep apnea syndrome and an associated medical condition are risk factors for postadenotonsillectomy respiratory complications. Risk reductions strategies should focus on their assessment.

Adenoidectomy↗
PubMed2002

Detection of a widespread clone of Pseudomonas aeruginosa in a pediatric cystic fibrosis clinic.

Cross-infection by Pseudomonas aeruginosa between unrelated patients with cystic fibrosis (CF) is believed to be uncommon. After detecting a genotypically identical strain of P. aeruginosa in five unrelated children with CF dying from severe lung disease, we determined its prevalence within a large CF clinic using pulsed-field gel electrophoresis and random amplified polymorphic DNA assays. The clinical status of P. aeruginosa-infected patients was also determined. Between September and December 1999, 152 patients, aged 3.9-20.7 years, provided sputum for culture. P. aeruginosa was detected in 118 children of mean (SD) age 13.5 (3.8) years. The genotyping techniques were concordant, showing that 65 (55%) infected patients carried an indistinguishable or closely related strain. No distinctive antibiogram or environmental reservoir was found. Patients with the clonal strain were more likely than those with unrelated isolates to have been hospitalized in the preceding 12 months for respiratory exacerbations. This study demonstrates extensive spread of a single, clonal strain of P. aeruginosa in a large pediatric CF clinic. Whether this strain is also more virulent than sporadic isolates remains to be determined. As transmissible strains could emerge elsewhere, other CF clinics may also need to consider molecular methods of surveillance for cross-infection.

Adolescent↗
PubMed2002

Sleep and breathing in Prader-Willi syndrome.

Prader-Willi syndrome (PWS) is a genetic disorder, with hypotonia being the predominant feature in infancy, and developmental delay, obesity, and behavioral problems becoming more prominent in childhood and adolescence. Children with this disorder frequently suffer from excessive daytime sleepiness and have a primary abnormality of the circadian rhythm of rapid eye movement sleep. They also have primary abnormal ventilatory responses to hypoxia and hypercapnia, and these abnormalities may be exacerbated by obesity. Children with PWS are at risk of a variety of abnormalities of breathing during sleep, including obstructive sleep apnea and sleep-related alveolar hypoventilation. Clinical evaluation should include a careful history of sleep-related symptoms and assessment of the upper airway and lung function. Polysomnography should be considered for those with symptoms suggestive of sleep-disordered breathing. Treatment options depend on the underlying problem, but may include behavioral interventions, weight control, adenotonsillectomy, and nocturnal ventilation.

Child↗
PubMed2002

Obstructive sleep apnea in children: do intranasal corticosteroids help?

Obstructive sleep apnea (OSA) is a common condition of childhood, and is associated with significant morbidity. Prevalence of the condition peaks during early childhood, due in part to adenoidal and tonsillar enlargement within a small pharyngeal space. The lymphoid tissues regress after 10 years of age, in the context of ongoing bony growth, and there is an associated fall in the prevalence of OSA. Obstruction of the nasopharynx by adenoidal enlargement promotes pharyngeal airway collapse during sleep, and the presence of large tonsils contributes to airway obstruction. Administration of systemic corticosteroids leads to a reduction in the size of lymphoid tissues due to anti-inflammatory and lympholytic effects. However, a short course of systemic prednisone has been demonstrated not to have a significant effect on adenoidal size or the severity of OSA, and adverse effects preclude the long-term use of this therapy. Intranasal corticosteroids are effective in relieving nasal obstruction in allergic rhinitis, and allergic sensitization is more prevalent among children who snore than among those who do not snore. Intranasal corticosteroids have also been demonstrated to reduce adenoidal size, independent of the individual's atopic status. There is preliminary evidence of an improvement in the severity of OSA in children treated with intranasal corticosteroids, but further studies are needed before such therapy can be routinely recommended. Prescribing clinicians should take into account the potential benefits to the patient, the age of the child, the presence of comorbidities such as allergic rhinitis, the agent used, and the dose and duration of treatment when considering such therapy.

Administration, Intranasal↗
PubMed2002

Scoring arousals in the home environment.

Arousals from sleep and consequent sleep disruption may be a causal link between sleep-disordered breathing and its sequellae in children. Quantification of arousals therefore makes an important contribution to the overall assessment of the sleep of a child with suspected obstructive sleep apnea (OSA) or other sleep disorders. Arousals are classically defined by changes in the electroencephalographic (EEG) channels, but most arousals in children involve body movement in addition to EEG changes. Several methods of quantifying arousals without the use of EEG have been proposed, with the aim of simplifying testing in children with suspected OSA so that it can be safely and efficiently performed in the child's home. The following paper gives a background to the assessment of arousals from sleep in children, and describes methods for detecting arousals and their potential application to recordings performed in a child's home.

Journal Article↗
PubMed2002

Diagnostic techniques for obstructive sleep apnoea: is polysomnography necessary?

Obstructive sleep apnoea (OSA) is a common condition of childhood with significant associated morbidity. The comprehensive evaluation of children who present with suggestive symptoms involves the overnight recording and assessment of both sleep and respiration by polysomnography in a sleep laboratory. These studies require resources and facilities that are not widely available and thus simpler, more available and less expensive alternatives have been sought. This review discusses the available alternatives to polysomnography for the evaluation of the child with suspected obstructive sleep apnoea.

Child↗
PubMed2002

Urinary incontinence in female adolescents with cystic fibrosis.

OBJECTIVES: Urinary incontinence is common in healthy women and occurs with increased frequency in adult women with chronic lung disease, including cystic fibrosis (CF). This study aimed to determine the prevalence, severity, and impact on daily life of urinary incontinence in female adolescents with CF. METHODS: An interviewer-administered questionnaire was conducted with females who were aged 12 years and older and attend the CF Clinic at the Royal Children's Hospital in Melbourne, Australia. RESULTS: Fifty-five (96%) of 57 eligible adolescents (age: 12-19 years) participated. Twenty-six (47%) reported ever having been incontinent of urine; 12 (22%) reported daytime incontinence twice a month or more. Median age of onset of incontinence was 13 years (range: 7-16 years). No relationship was seen with age, lung function, body mass index, or menarchal status. Coughing and laughing were the most commonly reported precipitants (affecting 84% and 68%, respectively). Of those with incontinence once a year or more, 42% reported that it sometimes prevented them from doing effective physiotherapy. Social life was affected by incontinence in approximately one third of respondents. Nearly half (42%) of affected adolescents had told no one, and only 2 had discussed the problem with their physician. CONCLUSIONS: Urinary incontinence is common in female adolescents with CF and is not related to illness severity. Urinary incontinence has a negative impact on the performance of chest physiotherapy. Given the lack of adolescent report and knowledge of treatment availability, inquiry about symptoms of urinary incontinence should be part of the routine assessment of female adolescents with CF.

Adolescent↗
PubMed2002

Differences in pulse oximetry technology can affect detection of sleep-disorderd breathing in children.

UNLABELLED: Newer pulse oximeters have been developed to be motion resistant and thus have few false alarms. However, they have not yet been evaluated in a pediatric sleep laboratory setting. While evaluating new oximeters for use in our laboratory, we obtained simultaneous pulse oximetry data from two Masimo oximeters and from two Nellcor oximeters during nocturnal polysomnography in children referred for sleep-disordered breathing (SDB). In series 1, comprising 24 patients, comparisons were made between a Masimo oximeter with 4-second averaging time and the Nellcor N-200 oximeter set for 3 to 5 second averaging. A maximum of 20 events per patient were randomly selected for analysis, an "event" being a desaturation of > or = 4% registered by either oximeter. Interobserver agreement for event classification was 93%. Eighty-eight percent of 220 desaturation events occurring during wakefulness and 38% of 194 events occurring during sleep were classified as motion artifact on the Nellcor oximeter. Neither the Masimo oximeter nor the transcutaneous oxygen probe confirmed that the desaturation was real, in most of these cases. During sleep, there were 119 events detected by either or both oximeters: 113 (95%) by the Nellcor versus 82 (69%) by the Masimo. For these 119 events, the extent of desaturation was slightly less for the Masimo than the Nellcor oximeter, 4.5 +/- 2.4% versus 5.5 +/- 2.5%, respectively. In series 2, 22 patients were studied comparing a Masimo Radical oximeter with 2 second averaging to the Nellcor N-200 oximeter. The extent of desaturation was slightly greater for the Masimo oximeter. The Masimo oximeter detected more non-artifactual desaturation events occurring during sleep than the Nellcor oximeter, 90% versus 76% (chi2 = 9.9, p < 0.01). In series 3, comprising 128 events in 5 patients, a Nellcor N-395 oximeter detected fewer desaturations during non-movement, sleep periods and had more movement related "desaturation" events, compared to a Masimo Radical oximeter. CONCLUSIONS: The Masimo oximeters register many fewer false desaturations due to motion artifact. Using 4-second averaging, a Masimo oximeter detected significantly fewer SaO2 dips than the Nellcor N-200 oximeter but using 2-second averaging, the Masimo oximeter detected more SaO2 dips than the Nellcor N-200 oximeter. The sensitivity and motion artifact rejection characteristics of the Nellcor N-395 oximeter are not adequate for a pediatric sleep laboratory setting. These findings suggest that in a pediatric sleep laboratory, use of a Masimo oximeter with very short averaging time could significantly reduce workload and improve reliability of desaturation detection.

Adolescent↗