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Biomedical subjects

R T Brouillette

Publications and source records attributed to R T Brouillette.

At least 19 recordsLinked to original sources
PubMed2001

Efficacy of fluticasone nasal spray for pediatric obstructive sleep apnea.

OBJECTIVE: We tested the hypothesis that a 6-week course of a nasal glucocorticoid spray would decrease the severity of obstructive sleep apnea in children with adenotonsillar hypertrophy. STUDY DESIGN: We conducted a randomized, triple-blind, placebocontrolled, parallel-group trial of nasal fluticasone propionate versus placebo in 25 children aged 1 to 10 years with obstructive sleep apnea proven on polysomnography. The primary outcome was the change from baseline in the frequency of mixed and obstructive apneas and hypopneas. RESULTS: Thirteen children received fluticasone, and 12 received placebo. The mixed/obstructive apnea/hypopnea index decreased from 10.7 +/- 2.6 (SE) to 5.8 +/- 2.2 in the fluticasone group but increased from 10.9 +/- 2.3 to 13.1 +/- 3.6 in the placebo group, P =.04. The mixed/obstructive apnea/hypopnea index decreased in 12 of 13 subjects treated with fluticasone versus 6 of 12 treated with placebo, P =.03. The frequencies of hemoglobin desaturation and respiratory movement/arousals also decreased more in the fluticasone group. Changes from baseline in tonsillar size, adenoidal size, and symptom score were not significantly different between groups. CONCLUSION: Nasal fluticasone decreased the frequency of mixed and obstructive apneas and hypopneas, suggesting that topical corticosteroids may be helpful in ameliorating pediatric obstructive sleep apnea.

Administration, Intranasal↗
PubMed2000

Treatment of sleep-disordered breathing in children with myelomeningocele.

The prevalence of moderate to severe sleep-disordered breathing (SDB) in patients with myelomeningocele may be as high as 20%, but little information is available regarding treatment of these patients. To assess the efficacy and complications of treatments for these children, we collected data on 73 patients from seven pediatric sleep laboratories. Obstructive sleep apnea (OSA, n = 30) and central apnea (n = 25) occurred more frequently than central hypoventilation (n = 12). We also describe a sleep-exacerbated restrictive lung disease type of SDB in 6 patients who had hypoxemia during sleep without apnea or central hypoventilation. For each type of SDB, effective treatments were identified in a stepwise process, moving towards more complex and invasive therapies. For OSA, adenotonsillectomy was often ineffective (10/14), whereas nasal continuous positive airway pressure (CPAP) was usually successful (18/21). For central apnea, methylxanthines and/or supplemental oxygen proved sufficient in 2 of 9 and 3 of 6, respectively, but noninvasive positive pressure ventilation was required in 7 children. For central hypoventilation, supplemental oxygen (alone or with methylxanthines), noninvasive positive pressure ventilation, and tracheostomy with positive pressure ventilation were effective in 3, 2, and 2 patients, respectively. Sleep-exacerbated restrictive lung disease always required supplemental oxygen treatment, but in 2 cases also required noninvasive positive pressure ventilation; nutritional and orthopedic procedures also were helpful. Posterior fossa decompression was used for the first three types of SDB, but data were insufficient to delineate specific recommendations for or against its use. In summary, evaluation by an experienced, multidisciplinary team can establish an effective treatment regime for a child with myelomeningocele and SDB.

Adolescent↗
PubMed2000

Computerised audiovisual event recording for infant apnoea and bradycardia.

Event recording, by differentiating between true and false events, has advanced the diagnosis and management of infants on home cardiorespiratory monitors; however, the pathogenesis of many events remains obscure. To clarify infant behaviours around the time of apnoea/bradycardia alarms, a computerised audiovisual event recording system (CAVERS) triggered by the apnoea/bradycardia recorder, has been developed. The audiovisual recording can begin up to 3 min before the alarm and can continue for up to 3 min after the alarm. CAVERS information is recorded for a total of 65 events in 13 infants. The CAVERS proves most helpful in documenting infant position and the wide variety of behaviours associated with bradycardic events. These behaviours range from sleep or quiet wakefulness to crying and generalised movements. Post-event activity is also highly variable. Interestingly, 20 of 65 events appear to terminate when the infant wakes to the audible monitor alarm. Nursing intervention is documented for 14 of 42 bradycardic events but only one of 23 apnoeic events. The CAVERS, by elucidating infant behaviours, provides information complementary to that given by cardiorespiratory event recording. It is suggested that infant monitors of the future should incorporate both audiovisual and cardiorespiratory data to elucidate optimally apparent life-threatening events, apnoeas and bradycardias.

Apnea↗
PubMed2000

Nocturnal pulse oximetry as an abbreviated testing modality for pediatric obstructive sleep apnea.

OBJECTIVE: To determine the utility of pulse oximetry for diagnosis of obstructive sleep apnea (OSA) in children. METHODS: We performed a cross-sectional study of 349 patients referred to a pediatric sleep laboratory for possible OSA. A mixed/obstructive apnea/hypopnea index (MOAHI) greater than or equal to 1 on nocturnal polysomnography (PSG) defined OSA. A sleep laboratory physician read nocturnal oximetry trend and event graphs, blinded to clinical and polysomnographic results. Likelihood ratios were used to determine the change in probability of having OSA before and after oximetry results were known. RESULTS: Of 349 patients, 210 (60%) had OSA as defined polysomnographically. Oximetry trend graphs were classified as positive for OSA in 93 and negative or inconclusive in 256 patients. Of the 93 oximetry results read as positive, PSG confirmed OSA in 90 patients. A positive oximetry trend graph had a likelihood ratio of 19.4, increasing the probability of having OSA from 60% to 97%. The median MOAHI of children with a positive oximetry result was 16.4 (7.5, 30.2). The 3 false-positive oximetry results were all in the subgroup of 92 children who had diagnoses other than adenotonsillar hypertrophy that might have affected breathing during sleep. A negative or inconclusive oximetry result had a likelihood ratio of.58, decreasing the probability of having OSA from 60% to 47%. Interobserver reliability for oximetry readings was very good to excellent (kappa =.80). CONCLUSIONS: In the setting of a child suspected of having OSA, a positive nocturnal oximetry trend graph has at least a 97% positive predictive value. Oximetry could: 1) be the definitive diagnostic test for straightforward OSA attributable to adenotonsillar hypertrophy in children older than 12 months of age, or 2) quickly and inexpensively identify children with a history suggesting sleep-disordered breathing who would require PSG to elucidate the type and severity. A negative oximetry result cannot be used to rule out OSA.

Adenoids↗
PubMed2000

Circumstances leading to a change to prone sleeping in sudden infant death syndrome victims.

CONTEXT: In addition to usual prone sleeping, unaccustomed prone sleeping represents a significant risk factor for sudden infant death syndrome (SIDS). However, little information is available regarding the circumstances leading caretakers to change the infant's sleep position to prone position in SIDS victims. OBJECTIVE: To determine, in a population of SIDS victims, the timing of a change to prone sleeping and the reason for that change in infants who were originally nonprone sleepers. DESIGN AND SETTING: Case series analysis from a questionnaire administered between 1991 and 1997 to parents and other caretakers of SIDS victims in the province of Quebec (Canada). SUBJECTS: One hundred fifty-seven SIDS cases occurring in the province during the study. RESULTS: Of the 157 SIDS cases studied, 139 were found in the prone position, although only 93 infants usually slept prone. Of the 64 nonprone sleepers, 34 had been changed to prone by the parents or another caretaker before death, and 18 had apparently turned to prone for the first time. In the 34 cases changed to prone, the change occurred <1 week before death for 21 infants; for 16 of those infants, death occurred the first or second time that they slept prone. In 56% of the cases changed from a nonprone to prone sleeping position, a caretaker other than the parents had precipitated the change. CONCLUSIONS: Ongoing campaigns to decrease the risk of SIDS should emphasize the risk of unaccustomed prone sleeping to both parents and secondary caretakers.

Female↗
PubMed1999

Head turning and face-down positioning in prone-sleeping premature infants.

BACKGROUND: Term infants may die of sudden infant death syndrome (SIDS) when they assume the face-straight-down or the face-near-straight-down head positions. Preterm infants have a higher SIDS rate, but it is not known how often they assume the face-straight-down and face-near-straight-down positions. OBJECTIVES: To determine the frequency and cardiorespiratory consequences of head turning and face-down head positioning in prone-sleeping premature infants. STUDY DESIGN: Supervised overnight cardiorespiratory and audiovisual recordings were conducted in 15 prone-sleeping preterm infants nearing hospital discharge: birth weight, 1178 101 (SEM) g, postconceptional age, 40 1.0 weeks. RESULTS: The preterm infants, studied at a younger postconceptional age than previously reported term infants, seldom turned their heads during sleep; therefore they rarely assumed the face-straight-down position (6 episodes in 3 infants) or the face-near-straight-down position (30 episodes in 6 infants). CONCLUSIONS: Prematurely born infants, known to be at increased risk of SIDS, rarely assume face-down positions when sleeping prone at approximately 40 weeks' postconceptional age. These results suggest that head turning during sleep is developmentally regulated and may have relevance to understanding the age distribution of SIDS.

Female↗
PubMed1999

Sleep-disordered breathing in patients with myelomeningocele: the missed diagnosis.

Moderate to severe sleep-disordered breathing (SDB) was identified in 20% (17 of 83) of children with spina bifida/myelomeningocele (SB/MM) at the Montreal Children's Hospital. The prevalence of SDB in patients with SB/MM elsewhere has not been determined. To establish current practices for identifying SDB in patients with SB/MM, questionnaires were sent to the coordinators of the 212 spina-bifida clinics in Canada and in the United States. Eighty-six (41%) questionnaires were returned, representing data on 13 349 patients. Although 67% of the responding centers reported availability of cardiorespiratory sleep studies, only 996 (7.5%) patients with SB/MM had been tested and only 418 (3.1%) patients had been diagnosed with SDB. Across clinics, the prevalence of SDB was directly related to the frequency of testing. Of 380 deaths over the past 10 years, SDB and sudden unexplained death during sleep were identified as the cause of death in 49 (12.8%) and 34 (8.9%) patients, respectively. Moderate to severe SDB may not have been identified in a significant number of patients with SB/MM because they have not been tested.

Cause of Death↗
PubMed1998

Acute airway obstruction in Hunter syndrome.

Hunter syndrome is one of the mucopolysaccharidoses, characterized by a deficiency of the lysosomal enzyme iduronate sulfatase. Among its physical manifestations, there are numerous head and neck signs, including characteristic facial features, macroglossia and short neck. The accumulation of glycosaminoglycans in the soft tissues of the head and neck can be associated with acute airway obstruction. We report a 7 year old boy with Hunter syndrome who developed acute airway compromise requiring an emergency tracheotomy. A review of the literature of airway management in patients with this disease is also presented.

Airway Obstruction↗
PubMed1998

Frequency and timing of recurrent events in infants using home cardiorespiratory monitors.

OBJECTIVE: To determine the incidence, type, timing, and factors predictive of recurrent significant events in infants with home cardiorespiratory monitors. STUDY DESIGN: We reviewed data accumulated for 147 patients with an event-recorder type of monitor. The infants were allocated to one of four diagnostic categories: apparent life-threatening events (ALTE, n = 73), former premature infants with persistent apnea and bradycardia (n = 29), siblings of victims of sudden infant death syndrome (SIDS) (n = 24), and parental anxiety after a nonsignificant event (n = 21). RESULTS: Compliance with monitoring was excellent; the monitors were used on 94% of the prescribed days. Fifty-three (36%) of 147 infants had significant events; of those, 46 (87%) experienced their first event during the first month of monitoring, and 69% of the events occurred during that first month. The most prevalent event type was a bradycardic event. Among infants in the ALTE group, events during the initial investigation period predicted the likelihood of events at home; 2 of the 47 infants (4%) with negative results for an investigation and no events recorded in hospital had apnea, and 4 had a bradycardic event (9%). In contrast, when significant events were recorded in hospital, the events were likely to recur at home (69% and 35% of the infants had apnea or bradycardia, respectively; p < 0.001). CONCLUSION: Because most apnea, bradycardia, and recurrent clinical events began during the first month of monitoring, we emphasize the need for vigilant follow-up care of infants immediately after institution of home monitoring. Readmission for investigation is warranted in infants with severe or multiple recurrent events.

Anxiety↗
PubMed1998

Sleep-disordered breathing in children with myelomeningocele.

BACKGROUND: Although patients with myelomeningocele and the Chiari II malformation are known to have sleep apnea and respiratory control deficits, the prevalence, types, severities, and associations of sleep-disordered breathing (SDB) have not been adequately defined. METHODS: A cross-sectional study of our myelomeningocele clinic population was undertaken to correlate polysomnographic results with historical data and findings from magnetic resonance imaging of the Chiari malformation, pulmonary function results, and nocturnal pulse oximetry. RESULTS: A questionnaire survey of symptoms was available for 107 of 109 children (98% of the clinic population), and 83 patients agreed to undergo overnight polysomnography. Breathing during sleep was classified as normal in 31 cases (37%), mildly abnormal in 35 cases (42%), and moderately/severely abnormal in 17 cases (20%). Among the 17 patients with moderately/severely abnormal SDB, 12 patients had predominantly central apneas and 5 had predominantly obstructive apnea. Patients with a thoracic or thoracolumbar myelomeningocele, those who had previously had a posterior fossa decompression operation, those with more severe brain-stem malformations, and those with pulmonary function abnormalities were more likely to have moderately/severely abnormal SDB, relative risks (95% confidence intervals) 9.2 (2.9 to 29.3), 3.5 (1.3 to 8.9), 3.0 (0.9 to 10.5), and 11.6 (1.6 to 81.3), respectively. Failure of obstructive SDB to resolve after adenotonsillectomy in four patients suggested abnormal control of pharyngeal airway patency during sleep. Nocturnal pulse oximetry accurately predicted moderately/severely abnormal SDB with a sensitivity of 100% and a specificity of 67%. CONCLUSIONS: The pathogenesis of SDB in patients with myelomeningocele involves the functional level of the spinal lesions, congenital and acquired brainstem abnormalities, pulmonary function abnormalities, disorders of upper airway maintenance, and sleep state. Polysomnography and nocturnal pulse oximetry should be performed in high-risk patients to detect and classify SDB.

Arnold-Chiari Malformation↗
PubMed1997

Do systemic corticosteroids effectively treat obstructive sleep apnea secondary to adenotonsillar hypertrophy?

To determine if pediatric obstructive sleep apnea syndrome (OSAS) caused by adenotonsillar hypertrophy (ATH) could be treated by a short course of systemic corticosteroids, we conducted an open-label pilot study in which standardized assessments of symptomatology, OSAS severity, and adenotonsillar size were performed before and after a 5-day course of oral prednisone, 1.1+/-0.1 (+/-SE) mg/kg per day. Outcome measures included symptom severity, adenotonsillar size, and polysomnographic measures of OSAS. Selection criteria included age from 1 to 12 years, ATH, symptomatology suggesting OSAS, an apnea/hypopnea index (AHI) > or = 3/hour, and intent to perform adenotonsillectomy. Only one of nine children showed enough improvement to avoid adenotonsillectomy. Symptomatology did not improve after corticosteroid treatment but did after removal of tonsils and adenoids. Polysomnographic indices of OSAS severity did not improve after corticosteroid treatment. After corticosteroids, tonsillar size decreased in only two patients, adenoidal size was only marginally reduced, and the size of the nasopharyngeal airway was not significantly increased. These results suggest that a short course of prednisone is ineffective in treating pediatric OSAS caused by ATH.

Adenoidectomy↗
PubMed1997

Evaluation of the newborn's blood gas status. National Academy of Clinical Biochemistry.

Blood gas measurements and complementary, noninvasive monitoring techniques provide the clinician with information essential to patient assessment, therapeutic decision making, and prognostication. Blood gas measurements are as important for ill newborns as for other critically ill patients, but rapidly changing physiology, difficult access to arterial and mixed venous sampling sites, and small blood volumes present unique challenges. This paper discusses considerations for interpretation of blood gases in the newborn period. Blood gas measurements and noninvasive estimations provide important information about oxygenation. The general goals of oxygen therapy in the neonate are to maintain adequate arterial PaO2 and SaO2, and to minimize cardiac work and the work of breathing. Pulse oximetry and transcutaneous oxygen monitoring are extraordinarily useful techniques of estimating and noninvasively monitoring the neonate's oxygenation, but each method has limitations. Arterial blood gas determinations of pCO2 provide the most accurate determinations of the adequacy of alveolar ventilation, but capillary, transcutaneous, and end-tidal techniques are also useful. An approach to and examples of acid-base disorders are presented. Three hemoglobin variants relevant to the newborn are considered: fetal hemoglobin, carboxyhemoglobin, and methemoglobin. Blood gases obtained in the immediate perinatal period can help assess perinatal asphyxia, but particular attention must be paid to the sampling site, the time of life, and the possible and proven diagnoses.

Acid-Base Equilibrium↗
PubMed1996

Pulse oximetry: accuracy of methods of interpreting graphic summaries.

Although pulse oximetry has been used to determine the frequency and extent of hemoglobin desaturation during sleep, movement artifact can result in overestimation of desaturation unless valid desaturations can be identified accurately. Therefore, we determined the accuracy of pulmonologists' and technicians' interpretations of graphic displays of desaturation events, derived an objective method for interpreting such events, and validated the method on an independent data set. Eighty-seven randomly selected desaturation events were classified as valid (58) or artifactual (29) based on cardiorespiratory recordings (gold standard) that included pulse waveform and respiratory inductive plethysmography signals. Using oximetry recordings (test method), nine pediatric pulmonologists and three respiratory technicians ("readers") averaged 50 +/- 11% (SD) accuracy for event classification. A single variable, the pulse amplitude modulation range (PAMR) prior to desaturation, performed better in discriminating valid from artifactual events with 76% accuracy (P < 0.05). Following a seminar on oximetry and the use of the PAMR method, the readers' accuracy increased to 73 +/- 2%. In an independent set of 73 apparent desaturation events (74% valid, 26% artifactual), the PAMR method of assessing oximetry graphs yielded 82% accuracy; transcutaneous oxygen tension records confirmed a drop in oxygenation during 49 of 54 (89%) valid desaturation events. In conclusion, the most accurate method (91%) of assessing desaturation events requires recording of the pulse and respiratory waveforms. However, a practical, easy-to-use method of interpreting pulse oximetry recordings achieved 76-82% accuracy, which constitutes a significant improvement from previous subjective interpretations.

Adolescent↗
PubMed1996

Face-straight-down and face-near-straight-down positions in healthy, prone-sleeping infants.

OBJECTIVE: To determine the frequency and physiologic consequences of the face-straight-down (FSD) position, a postulated mechanism for the sudden infant death syndrome in prone-sleeping infants. STUDY DESIGN: A survey of 151 infants, aged 1 to 7 months, in Montreal showed that 33% slept prone. Ten healthy prone-sleeping infants were studied in their homes at age 10 to 22 weeks. Infrared video and cardiorespiratory recordings were made on 3 consecutive nights in the prone (nights 1 and 3) and lateral (night 2) positions. RESULTS: Infants maintained the prone position during 17 of 19 studies, but only 4 of 9 infants maintained the lateral position. The FSD position was observed 27 times in 17 prone nights: median frequency, 0.6 times per night (interquartile range, 0 to 4), and median total duration, 3.3 minutes (0.8% of total sleep time). A related position, the face-near-straight-down (FNSD) position, occurred more often, 5.3 (1 to 10) time per prone night, for 22.4 minutes (5.8% of total sleep time). Most periods in the FSD and FNSD position had no physiologic consequences; however, 14% of FSD and 3% of FNSD episodes were associated with airway obstruction as indicated by snoring, paradoxical respiratory movements, apnea, and/or increased partial pressure of transcutaneous carbon dioxide. Spontaneous arousal and head turning terminated the FSD and FNSD episodes. CONCLUSION: The FSD and FNSD positions occur commonly in healthy prone-sleeping infants, and these positions can cause airway obstruction. We speculate that those infants with sudden infant death syndrome found in the FSD or FNSD position either have a congenital or an acquired defect in the arousal-head turning response or have encountered insurmountable environmental factors that prevent effective head turning.

Airway Obstruction↗
PubMed1996

Can sleep and wakefulness be distinguished in children by cardiorespiratory and videotape recordings?

Polysomnography, including EEG recording, is the standard method to diagnose obstructive sleep apnea (OSA) in children and adults. Diagnosis of OSA would be considerably simplified if it was shown that sleep could be distinguished from wakefulness without EEG recordings. Therefore, we compared sleep/wakefulness classification using a simplified cardiorespiratory-video (CRV) method with standard polysomnography in 20 children undergoing in-hospital evaluation for OSA. The channels for the simplified montage were chosen because they (1) were suitable for unattended, home recordings, (2) allowed the diagnosis of apneas, hypopneas, desaturation, and movement/arousals, and (3) did not require attachment to the head or face that might disturb the childs sleep. Sleep staging by the two methods was blinded to results of the other method. We evaluated 21,832 30-s epochs--1,092+/-111 (SD) per child. Across 20 subjects, 79.7+/-7.1% of the epochs were sleep. The simplified montage agreed with polysomnographic classification of sleep/wakefulness for 93.8+/-2.5% of the epochs. Of all sleep epochs, 97.7 (96.4, 98.1%) median (interquartile range), were correctly classified; sleep predictive value of the CRV method was 95.2+/-2.8%. Of all epochs classified as wakefulness by polysomnography, 80.1+/-12.8% were correctly classified by the CRV method. The wakeful predictive value was 88.7+/-2.6%. Kappa values averaged 0.8+/-0.1, indicating that agreement between the CRV method and polysomnography did not occur by chance and that the level of agreement was excellent. Thus, sleep can be distinguished from wakefulness in children being evaluated for OSA using a combination of cardiorespiratory and videotape recordings. These results suggest that the CRV method would be useful in a pediatric laboratory setting where EEG recordings are not always possible. They also suggest that overnight, unattended CRV recordings in a childs own home could correctly distinguish sleep from wakefulness.

Child↗
PubMed1996

Cardiorespiratory sleep studies for children can often be performed in the home.

We developed a portable recording system, suitable for unattended use in a patient's home, that quantitates the essential diagnostic elements of pediatric obstructive sleep apnea syndrome (OSAS): obstructive, mixed and central apneas and hyponeas; hemoglobin saturation, sleep vs. wakefulness; body and head positions; snoring: and sleep disturbance. The present paper reviews validation studies and summarizes two recent studies that demonstrate the unique advantages of performing clinical and research cardiorespiratory sleep studies in the child's home. Development of inexpensive, portable records that integrate audiovisual and physiologic information will make such home recordings more widely available.

Humans↗