Biomedical subjects

G M Loughlin

Publications and source records attributed to G M Loughlin.

At least 19 recordsLinked to original sources

PubMed2000

Pulse oximetry is a poor predictor of hypoxemia in stable children with sickle cell disease.

OBJECTIVE: To evaluate the accuracy of the pulse oximeter to detect hypoxemia in patients with sickle cell disease in an ambulatory care setting. STUDY DESIGN: Simultaneous measurements of PaO(2), arterial oxygen saturation by co-oximetry (criterion standard), and pulse oximetry were performed in 21 children with sickle cell disease during 22 outpatient visits. The bias and precision of the pulse oximeter compared with measured arterial oxygen saturation by co-oximetry were determined. The sensitivity, specificity, and positive and negative predictive values of the pulse oximeter to detect hypoxemia (PaO(2) <70 mm Hg) were also calculated. RESULTS: The mean difference between pulse oximetry and measured oxygen saturation (bias) was 5.0% and the SD (precision) was 5.3. Twenty-one patients had a PaO(2) greater than 70 mm Hg; 7 of these (33%) were predicted to be hypoxic by pulse oximetry with values less than 93%, for a specificity to detect normoxia of 67%. CONCLUSION: Making treatment decisions based on pulse oximetry data alone in patients with sickle cell disease who are not acutely ill may be inappropriate.

Adolescent↗

PubMed2000

Oropharyngeal dysphagia and aspiration in patients with ataxia-telangiectasia.

OBJECTIVES: To determine whether patients with ataxia-telangiectasia exhibit oropharyngeal dysphagia with concomitant aspiration and to examine the relationships among swallowing function, age, and nutritional status. STUDY DESIGN: Seventy patients (mean age, 10.7 years; range, 1.8 to 30 years) had feeding/swallowing and nutritional evaluations. Fifty-one patients, in whom there were concerns about swallowing safety, were examined with a standardized videofluoroscopic swallow study. RESULTS: Fourteen of the 51 patients (27%) with histories suggestive of dysphagia demonstrated aspiration. Of these, silent aspiration (aspiration without a cough) occurred in 10 (71%) patients. Aspirators were significantly older than non-aspirators (mean age, 16.9 vs 10.8 years; P =.002). Advancing age was the strongest factor associated with aspiration during continuous drinking (P =.01). In patients with ataxia-telangiectasia, weight and weight/height were abnormally low at all ages and most compromised in older patients. Patients who aspirated had significantly lower mean weight (P <.002) and weight/height z scores (P <.001) than did patients who did not aspirate. CONCLUSIONS: Oropharyngeal dysphagia is common and appears to be progressive in patients with ataxia-telangiectasia. Older patients also have a higher incidence of poorer nutritional status. The relationship between dysphagia and nutritional status deserves further investigation.

Age Factors↗

PubMed2000

Cardiorespiratory function is significantly improved following corrective surgery for severe pectus excavatum. Proposed treatment guidelines.

BACKGROUND: Pectus excavatum is a congenital chest abnormality which may become more marked during childhood and teenage growth. Young teenagers with severe PE deformities often become short of breath during strenuous exercise and complain of becoming easily fatigued. The pathophysiologic effects of PE remain controversial because they have been difficult to measure, especially in young children. Symptomatic patients often have significant subjective improvement during exercise following PE repair and there is a major cosmetic impact on teenagers with severe deformities. This study was designed to measure pulmonary and cardiac function with exercise before and after corrective surgery. METHODS: Pulmonary function testing and incremental exercise testing were performed in 36 adolescents with pectus excavatum (PE) and 10 age-matched, healthy control subjects. Six months after corrective surgery was performed, 15 of these PE patients and 6 control subjects were re-evaluated for pulmonary function. RESULTS: Before surgery, PE subjects had a lower forced vital capacity (FVC) than controls; there was no change in FVC after surgery. Before surgery, 58% of PE patients had subjective complaints of exercise limitation; 66% of the patients were significantly improved after surgery. PE subjects exercised at a similar workload to controls. Respiratory parameters during exercise were similar between the two groups before surgery, indicating that exercise was not limited by restrictive lung disease. After surgery, PE subjects exercised longer and had a higher oxygen pulse than before surgery, whereas controls showed no such changes. Although some PE subjects showed mild restrictive lung function, surgical repair did not influence this mild degree of restriction. CONCLUSIONS: After corrective surgery, PE patients have increased exercise tolerance and a higher oxygen pulse. Oxygen pulse is a measure of cardiac output. Results suggest that PE repair improves cardiopulmonary function during vigorous exercise. Based upon these studies, and our experience in the treatment of more than 700 surgical patients with pectus excavatum over a 40-year period, guidelines for the diagnosis and management of children with pectus excavatum are proposed.

Adolescent↗

PubMed1999

Chloride transport in the ferret trachea.

A net secretion of chloride stimulated by carbamylcholine was observed in whole trachea. Luminal anthracene-9-carboxylic acid inhibited the net secretion of chloride and the transepithelial potential difference across the isolated trachea. Submucosal ouabain inhibited the net secretion of chloride and submucosal ouabain, or submucosal bumetanide inhibited the transepithelial potential difference across the isolated trachea. Short-circuited flat sheets of trachea manifested a net secretion of chloride induced by carbamylcholine. Serosal ouabain inhibited the short-circuit current and net chloride flux across isolated flat sheets of trachea.

Animals↗

PubMed1998

Natural history of primary snoring in children.

It is not known whether children with primary snoring (PS) progress to develop obstructive sleep apnea syndrome (OSAS). Therefore, we repeated polysomnography in a cohort of 20 children diagnosed 1-3 years previously with PS. All children initially presented with symptoms suggestive of OSAS. They were diagnosed with PS when initial polysomnography demonstrated snoring, with less than one obstructive apnea per hour, normal gas exchange, and infrequent arousals. Of 75 potential candidates, 20 were available for reevaluation (33 could not be contacted, 8 had undergone tonsillectomy and adenoidectomy, and 14 declined). Mean age was 6 +/- 4 (SD) years at the time of the initial study. The initial apnea index was 0.2 +/- 0.3, SpO2 nadir 95 +/- 2%, and peak end-tidal PCO2 was 47 +/- 3 mm Hg. At follow-up, all children were reported by their parents to still be snoring; in 20% snoring had reportedly increased, and in 70% there was no change. Eighty percent were thought to have difficulty breathing during sleep. For the group as a whole, there were no significant changes in apnea index, SpO2, or peak end-tidal PCO2. However, two children had mild OSAS on repeat polysomnography (apnea index of 3). We conclude that, in most children, primary snoring does not progress to OSAS over the course of several years. This study indicates that OSAS in the few individuals who do progress is mild. Parental concern about children's breathing patterns during sleep is a poor predictor of polysomnographic abnormalities. However, because many patients were lost to follow-up in this study, further prospective studies are needed.

Adolescent↗

PubMed1998

Sleep-disordered breathing in children with achondroplasia.

OBJECTIVE: Our objective was to characterize sleep-disordered breathing in 88 children with achondroplasia aged 1 month to 12.6 years. RESULTS: At the time of their initial polysomnography, five children had previously undergone tracheostomy, and seven children required supplemental oxygen. Initial polysomnography demonstrated a median obstructive apnea index of 0 (range, 0 to 19.2 apneas/hr). The median number of central apneas with desaturation per study was 0.5 (0 to 49), the median oxygen saturation nadir was 91% (50% to 99%), and the median peak end-tidal pCO2 was 47 mm Hg (36 to 87 mm Hg). Forty-two children (47.7%) had abnormal initial study results, usually caused by hypoxemia. Two children with severe obstructive sleep apnea eventually required continuous positive airway pressure therapy, and three additional children required tracheostomies. CONCLUSIONS: (1) Children with achondroplasia often have sleep-related respiratory disturbances, primarily hypoxemia. (2) The majority do not have significant obstructive or central apnea; however, a substantial minority are severely affected. (3) Tonsillectomy and adenoidectomy decreases the degree of upper airway obstruction in most but not all children with achondroplasia and obstructive sleep apnea. (4) Restrictive lung disease can present at a young age in children with achondroplasia.

Achondroplasia↗

PubMed1997

High prevalence of allergic sensitization in children with habitual snoring and obstructive sleep apnea.

STUDY OBJECTIVE: To determine whether allergic sensitization occurs frequently in children with habitual snoring and whether allergy predicts the occurrence of obstructive sleep apnea syndrome (OSAS) in snoring children. DESIGN: Prospective study of 39 children with habitual snoring who were referred for polysomnography. SETTING: Pediatric pulmonary sleep disorders clinic in a tertiary referral center. MEASUREMENTS: Subjects underwent a complete history and physical examination. To assess for the presence of allergic sensitization, a multiantigen radioallergosorbent test (RAST) was performed on serum samples. Subjects then underwent nocturnal polysomnography to determine the presence and severity of OSAS. RESULTS: Fourteen subjects (36%) demonstrated sensitivity to allergens; this is higher than expected for the general pediatric population. The frequency of OSAS was increased in subjects with positive RAST results compared to those with negative RAST results (57% vs 40%; chi 2 = 9.11; p < 0.01). CONCLUSION: Allergy is frequently present in pediatric patients with habitual snoring. Furthermore, the presence of allergy is associated with an increased risk of OSAS in this population.

Child↗

PubMed1996

Polysomnography in the evaluation of readiness for decannulation in children.

OBJECTIVE: To determine whether polysomnography is useful in the evaluation of readiness for decannulation in children with long-term tracheotomy. DESIGN: Descriptive, retrospective case series. SETTING: Tertiary care pediatric center, pediatric sleep disorders laboratory, and pediatric otolaryngology referral center. PATIENTS: Children (younger than 18 years) with tracheotomy undergoing polysomnography to assess their dependence on tracheotomy. INTERVENTION: Polysomnography in all patients; endoscopy and decannulation in those judged clinically ready. MAIN OUTCOME MEASURES: Success of decannulation. RESULTS: Thirteen of 16 patients with favorable polysomnographic data were successfully decannulated. CONCLUSION: Polysomnography is a useful supplement to airway endoscopy in the evaluation of readiness for decannulation in children with long-term tracheotomy and dynamic airway issues.

Child↗

PubMed1996

Evaluation of pulmonary function and polysomnography in obese children and adolescents.

Obese adults have an increased prevalence of pulmonary disorders. Although childhood obesity is a common problem, few studies have evaluated the pulmonary complications of obesity in the pediatric population. We, therefore, performed pulmonary function tests (PFTs), polysomnography, and multiple sleep latency tests (MSLTs) in 22 obese children and adolescents [mean age, 10 +/- 5 (SD) years; 73 percent female; 184 +/- 36 percent ideal body weight], none of whom presented because of sleep or respiratory complaints. PFTs were normal in all but two subjects. Ten (46 percent) subjects had abnormal polysomnograms. There was a positive correlation between the degree of obesity and the apnea index (r = 0.47, P < 0.05), and an inverse correlation between the degree of obesity and the Sa0(2) nadir (r = -0.60, P < 0.01). The degree of sleepiness on MSLT correlated with the degree of obesity (r = -0.50, P < 0.05). We conclude that obese children and adolescents have a high prevalence of sleep-disordered breathing, although in many cases it is mild. Obstructive sleep apnea syndrome (OSAS) improved following tonsillectomy and adenoidectomy. We recommend that pediatricians have a high index of suspicion for OSAS when evaluating obese patients, and that polysomnography be considered for these patients.

Adolescent↗

PubMed1996

Chest wall constriction after too extensive and too early operations for pectus excavatum.

BACKGROUND AND METHODS: Since 1990 we have evaluated 12 children and teenagers in whom severe cardiorespiratory symptoms have developed due to failure of chest wall growth after very extensive pectus excavatum operations (removal of five or more ribs) at very early ages (< 4 years). RESULTS: Apparently these extensive procedures have removed or prevented growth center activity, which resulted in restriction of chest wall growth with marked limitation of ventilatory function. The forced vital capacity ranged from 30% to 50% of predicted and the forced expiratory volume in 1 second from 30% to 60%. All patients are symptomatic with mild exercise and cannot compete in running games. Our protocol for critical evaluation includes exercise pulmonary function studies and axial computed tomographic reconstruction. CONCLUSIONS: This report is an alert to recognize such patients and also to recommend delay in operative repair in small children until at least 6 to 8 years of age. The younger the patient the more limited the chest wall resection for pectus excavatum should be. Five of these patients have had a chest cavity expansion operation with encouraging early results.

Adolescent↗

PubMed1996

Cardiorespiratory function before and after corrective surgery in pectus excavatum.

OBJECTIVE: To determine whether pectus excavatum (PE) results in cardiopulmonary abnormalities, and whether surgical repair results in improvement. METHODS: We performed pulmonary function testing and incremental exercise testing in 36 adolescents with PE (aged 16 +/- 3 (SD) years) and 10 age-matched, healthy control subjects. Fifteen PE subjects were reexamined postoperatively, as were six control subjects. RESULTS: Preoperatively, PE subjects had a significantly lower forced vital capacity than control subjects had (81% +/- 14% vs 98% +/- 9% of the predicted value; p < 0.001). Chest computed tomography ratios of internal transverse to antero-posterior diameters correlated inversely with total lung capacity (r = 0.56; p < 0.01). Fifty-eight percent of PE subjects had subjective complaints of exercise limitation. PE subjects exercised at a workload similar to that of control subjects. Maximal heart rate and O2 pulse did not differ between the two groups. Respiratory measurements during exercise were similar between the two groups. Respiratory measurements during exercise were similar between the two groups. Postoperatively there was no change in forced vital capacity (as a percentage of the predicted value). The PE subjects exercised for a slightly longer period and had a slightly higher O2 pulse, whereas control subjects showed no change. CONCLUSION: Some subjects with PE have mild restrictive lung disease, which is not affected by surgical repair. Postoperatively they have a slight increase in exercise tolerance and O2 pulse, which suggests improved cardiac function during exercise. However, the clinical implications of this modest improvement are unclear.

Adolescent↗

PubMed1996

Obstructive sleep apnea in children.

The obstructive sleep apnea syndrome is a common cause of morbidity during childhood. Childhood obstructive sleep apnea syndrome is usually secondary to adenotonsillar hypertrophy. Other risk factors include craniofacial anomalies, obesity, and neuromuscular disease. Symptoms include snoring and difficulty breathing during sleep. Definitive diagnosis is made by polysomnography. Normative polysomnographic parameters vary with age; thus age-appropriate norms must be used. In contrast to adults, children often manifest a pattern of persistent partial airway obstruction during sleep, rather than cyclical, discrete obstructive apneas. Most children are cured by tonsillectomy and adenoidectomy. However, some children require further therapy, such as continuous positive airway pressure.

Adolescent↗

PubMed1996

Specialized studies in pediatric dysphagia.

The evaluation and management of the pediatric patient with a feeding and swallowing disorder may require the use of specialized studies to evaluate specific aspects of swallowing function; to judge the consequences of the swallowing dysfunction; and to assess factors that may be contributing to swallowing dysfunction. Instrumental assessment of swallowing function may include upper gastrointestinal studies, videofluoroscopy or videofluoroscopic swallow studies, ultrasonography, radionuclide imaging, fiberoptic endoscopy of swallowing, and cervical auscultation. Procedures that assess the consequences and/or identify factors contributing to swallowing dysfunction may include pulse oximetry, chest x-rays, laryngoscopy and/or bronchoscopy, and pulmonary function tests. The use of such specialized procedures to evaluate children with dysphagia is the focus of this article.

Deglutition Disorders↗

PubMed1996

Effect of sleep deprivation on driving safety in housestaff.

Sleep deprivation is known to affect driving safety. Housestaff (HS) are routinely sleep-deprived when on call. We hypothesized that this would affect their driving. We therefore administered questionnaires regarding driving to 70 pediatric HS, who were on call every fourth night, and to 85 faculty members (FAC), who were rarely disturbed at night. HS were questioned about events during their residency, and FAC were questioned about events during the preceding three years. There was an 87% response rate for each group. HS slept 2.7 +/- 0.9 (SD) hours when on call vs 7.2 +/- 0.8 hours when not on call (p < 0.001). 44% of HS had fallen asleep when stopped at a light, vs 12.5% FAC (p < 0.001). 23% of HS had fallen asleep while driving vs. 8% FAC (ns). A total of 49% of HS had fallen asleep at the wheel; 90% of these events occurred post-call. In contrast, only 13% of FAC had fallen asleep at the wheel (p < 0.001). HS had received a total of 25 traffic citations for moving violations vs. 15 for FAC and were involved in 20 motor vehicle accidents vs. 11 for FAC. One traffic citation clearly resulted from HS falling asleep at the wheel vs. none for FAC. We conclude that HS frequently fall asleep when driving post-call. We speculate that current HS work schedules may place some HS at risk for injury to themselves and others. Further study, using prospectively objective measures is indicated.

Accidents, Traffic↗

PubMed1996

Polysomnography after adenotonsillectomy in mild pediatric obstructive sleep apnea.

OBJECTIVES: a) To determine the need for intensive monitoring on the first operative night of surgery in children undergoing adenotonsillectomy for mild obstructive sleep apnea; b) to examine the effect of narcotics on postoperative obstructive sleep apnea. DESIGN: Randomized, prospective study. SETTING: University hospital. PATIENTS: Children, ranging in age between 1 and 18 yrs, presented to the Pediatric Otolaryngology Clinic for adenotonsillectomy for mild obstructive sleep apnea defined as from one to 15 obstructive apnea events per hour on preoperative polysomnogram. INTERVENTIONS: Patients were assigned to receive either a narcotic- or a halothane-based anesthetic for adenotonsillectomy. A postoperative polysomnogram was performed in the pediatric intensive care unit on the first operative night. MEASUREMENTS AND MAIN RESULTS: Eighteen patients were recruited, 15 of whom met inclusion criteria: nine patients received a halothane-based anesthetic and six patients received a fentanyl-based anesthetic. When the data were analyzed by pooling both groups, the differences between pre- and postoperative sleep studies demonstrated a reduction in the number of obstructive events and less severe oxygen desaturations on the operative night. Total sleep time between the two sleep studies decreased from 371 +/- 13 to 304 +/- 14 mins. The number of obstructive apnea events/hr decreased as well. The lowest oxygen saturation measured during rapid eye movement sleep was 78 +/- 5% preoperatively and 92 +/- 1% postoperatively. CONCLUSIONS: Our data suggest that children without underlying medical conditions, neuromotor diseases, or carniofacial abnormalities, 1 to 18 yrs of age, who suffer from mild obstructive sleep apnea, have improvements documented by polysomnography on the night of surgery following adenotonsillectomy and do not necessarily need to be monitored intensively. These findings were not significantly affected by the choice of intraoperative anesthetic.

Adenoidectomy↗

PubMed1995

Supplemental oxygen during sleep in children with sleep-disordered breathing.

Supplemental O2 is sometimes used to treat children with the obstructive sleep apnea syndrome (OSAS). However, its effects have not been studied. We therefore evaluated the use of supplemental O2 during sleep in children with OSAS. Oxygen and room air were delivered via nasal cannula at 1 L/min for 4 h each in a randomized, double-blind fashion. Twenty-three children were studied (mean age, 5 +/- 3 [SD] yr). Patients had a higher mean SaO2 and higher SaO2 nadir when breathing O2. There was no difference in the number (10.9 +/- 20.6/h on O2 versus 13.5 +/- 19.3 on room air) or duration of obstructive apneas. Although there was no overall change in end-tidal PCO2 when patients breathed O2, two children showed a significant increase. We conclude that breathing supplemental O2 during sleep in children with OSAS results in improved oxygenation and in most cases does not exacerbate sleep-disordered breathing. However, end-tidal PCO2 should be monitored in children with OSAS receiving O2 therapy. We speculate that supplemental O2 does not depress the ventilatory drive during sleep in most children with OSAS.

Child↗

PubMed1995

Inability of clinical history to distinguish primary snoring from obstructive sleep apnea syndrome in children.

STUDY OBJECTIVE: To determine whether primary snoring (PS) could be distinguished from childhood obstructive sleep apnea syndrome (OSAS) by clinical history. DESIGN: Retrospective study of clinical history of 83 children with snoring and/or sleep disordered breathing who were referred for polysomnography. SETTING: Tertiary referral center; pediatric pulmonary sleep apnea clinic. MEASUREMENTS: We evaluated the ability of a clinical obstructive sleep apnea (OSA) score and other questions about sleep, breathing, and daytime symptoms to distinguish PS from OSAS in children. Parents were asked about the child's snoring, difficulty breathing, observed apnea, cyanosis, struggling to breathe, shaking the child to "make him or her breathe," watching the child sleep, afraid of apnea, the frequency and loudness of snoring, and daytime symptoms such as excessive daytime sleepiness (EDS). RESULTS: Based on polysomnography results, 48 patients were classified as PS and 35 as OSAS. Peak endtidal CO2 (49 +/- 3.2 vs 55 +/- 8.2 [SD] mm Hg); lowest arterial oxygen saturation measured by pulse oximetry (95 +/- 1.9 vs 82 +/- 14%); and apnea/hypopnea index (0.27 +/- .3 vs 8.4 +/- 6 events/h) indicated that the diagnostic criteria for PS versus OSA were reasonable. There were no differences between PS and OSA patients with respect to age, sex, race, failure to thrive, obesity, history of EDS, snoring history, history of cyanosis during sleep, or daytime symptoms except for mouth breathing. There were no significant differences in sleep variables between PS patients and those with any severity of OSAS. The OSA score misclassified about one of four patients. Comparing PS and OSA patients, significant findings were daytime mouth breathing (61 vs 85%; p = 0.024); observed apnea (46 vs 74%; p = 0.013); shaking the child (31 vs. 60%; p = 0.01); struggling to breathe (58 vs 89%; p = 0.003); and afraid of apnea (71 vs 91%; p = 0.028). However, none of these were sufficiently discriminatory to predict OSAS. CONCLUSION: We conclude that PS in children cannot be reliably distinguished from OSAS by clinical history alone.

Case-Control Studies↗

PubMed1995

Making the most of pulse oximetry.

A noninvasive device that gives continuous oxygenation readings has great appeal, and pulse oximetry has enjoyed wide acceptance. To use it most effectively, though, you need to understand the principles it's based on and know its limitations.

Ambulatory Care↗