Biomedical subjects

Raouf S Amin

Publications and source records attributed to Raouf S Amin.

12 recordsLinked to original sources

PubMed2006

Determination of respiratory phase during acquisition of airway cine MR images.

Subjects were imaged on a 1.5-T Signa MRI system using the head-neck vascular coil. An axial fast gradient echo cine, at the base of the second cervical vertebra, was obtained. A total of 128 images were acquired with a rapid image acquisition (one per second) over several respiratory cycles. The analog signal from the MR scanner (RF unblank) was utilized to determine the duration of the cine MR sequence. The phase of respiration was determined by analyzing the nasal air flow connected via pressure tubing to a pressure transducer outside the MR scanner room. We were thus able to determine the phase of respiration during acquisition of individual airway cine MR images. There was a wide range of airway volume measurements over the respiratory cycle with the lowest volume at end expiration and the highest at peak inspiration.

Adolescent↗

PubMed2006

Comparison of lingual tonsil size as depicted on MR imaging between children with obstructive sleep apnea despite previous tonsillectomy and adenoidectomy and normal controls.

BACKGROUND: Cine MRI has become a useful tool in the evaluation of patients with persistent obstructive sleep apnea (OSA) despite previous surgical intervention and in patients with underlying conditions that render them susceptible to multilevel airway obstruction. Findings on cine MRI studies have also increased our understanding of the mechanisms and anatomic causes of OSA in children. OBJECTIVE: To compare lingual tonsil size between children with OSA and a group of normal controls. In addition, a subanalysis was made of the group of children with OSA comparing lingual tonsils between children with and without underlying Down syndrome. MATERIALS AND METHODS: Children with persistent OSA despite previous palatine tonsillectomy and adenoidectomy and controls without OSA underwent MR imaging with sagittal fast spin echo inversion-recovery images, and lingual tonsils were categorized as nonperceptible at imaging or present and measurable. When present, lingual tonsils were measured in the maximum anterior-posterior diameter. If lingual tonsils were greater than 10 mm in diameter and abutting both the posterior border of the tongue and the posterior pharyngeal wall, they were considered markedly enlarged. RESULTS: There were statistically significant differences between the OSA and control groups for the presence vs. nonvisualization of lingual tonsils (OSA 33% vs. control 0%, P=0.0001) and mean diameter of the lingual tonsils (OSA 9.50 mm vs. control 0.0 mm, P=0.00001). Within the OSA group, there were statistically significant differences between children with and without Down syndrome for the three lingual tonsil width categories (P=0.0070) and occurrence of markedly enlarged lingual tonsils (with Down syndrome 35% vs. without Down syndrome 3%, P=0.0035). CONCLUSIONS: Enlargement of the lingual tonsils is relatively common in children with persistent obstructive sleep apnea after palatine tonsillectomy and adenoidectomy. This is particularly true in patients with Down syndrome.

Adenoidectomy↗

PubMed2005

Left ventricular function in children with sleep-disordered breathing.

Severe obstructive sleep apnea in children leads to congestive heart failure. We studied the early changes in left ventricular function across a range of severity of the disorder. A dose-dependent decrease in diastolic function with increased severity of obstructive apnea was demonstrated.

Adolescent↗

PubMed2005

Asthma as a risk factor for respiratory complications after adenotonsillectomy in children with obstructive breathing during sleep.

BACKGROUND: Children with asthma are at increased risk for obstructive breathing during sleep. Adenotonsillectomy, the treatment of choice for obstructive breathing during sleep, is associated with significant postoperative respiratory morbidity. OBJECTIVE: To determine whether asthma is a risk factor for respiratory complications after adenotonsillectomy in children with obstructive breathing during sleep. METHODS: This case-control study compared 115 children aged 3 to 18 years with respiratory complications after adenotonsillectomy (study group) with 115 children without respiratory complications after adenotonsillectomy (control group). RESULTS: The postoperative respiratory complications ranged from oxygen desaturation to respiratory failure that required mechanical ventilation. The study group had a higher proportion of children with asthma (P < .01). Logistic regression analysis showed that asthma increases the odds of postoperative respiratory complications to 4.4 (95% confidence interval, 2.13-9.0), after controlling for age, weight greater than the 97th percentile for age, sex, race, and medical conditions other than asthma. CONCLUSIONS: In children with obstructive breathing during sleep, the presence of asthma is associated with an increased risk of respiratory complications after adenotonsillectomy.

Adenoidectomy↗

PubMed2005

Pulmonary management of the patient with muscular dystrophy.

Pulmonary involvement is common in patients with muscular dystrophy, and routine screening for evidence of respiratory muscle dysfunction should be performed. Testing for respiratory muscle strength, as well as an assessment for sleep-disordered breathing, should be obtained in consultation with a specialist. Adequate airway clearance and correction of impaired ventilation are the key components of pulmonary management in this group of patients. Also, special emphasis on airway clearance is recommended during upper respiratory infections, as well as in the postoperative period. Early initiation of ventilatory support has been shown to result in longer life expectancy.

Child↗

PubMed2004

Structural cardiac changes as a predictor of respiratory complications after adenotonsillectomy for obstructive breathing during sleep in children.

BACKGROUND AND PURPOSE: To determine the association between structural cardiac changes and postoperative respiratory complications after adenotonsillectomy for obstructive breathing during sleep. PATIENTS AND METHODS: Forty-eight children, ages 2-18 years, undergoing adenotonsillectomy for obstructive breathing during sleep were recruited for this case control study. The case group consisted of 24 children with postoperative respiratory complications after adenotonsillectomy who also had an echocardiogram. An equal number of children without postoperative respiratory complications after adenotonsillectomy were recruited as controls. Left ventricular mass (LVM) was calculated from 2D guided M mode echocardiographic measurements of the left ventricle. Left ventricular mass index (LVMI) was calculated as left ventricular mass/height(2.7). Left ventricular hypertrophy (LVH) was defined as LVMI index greater than the 95th percentile for age. The two groups were compared for demographic variables and cardiac structure. RESULTS: The two groups did not significantly differ by age, height, gender or racial distribution. LVH and right ventricular (RV) dimension greater than the 95th percentile for age remained significantly associated with the occurrence of postoperative respiratory complications after controlling for body mass index (BMI) Z score, age, gender, race, systolic and diastolic blood pressure. CONCLUSIONS: The increased prevalence of structural cardiac changes in the group with complications (P<0.01) suggests an underlying cardiac origin for postoperative respiratory complications in this group of children.

Adenoidectomy↗

PubMed2004

Twenty-four-hour ambulatory blood pressure in children with sleep-disordered breathing.

Obstructive sleep apnea causes intermittent elevation of systemic blood pressure (BP) during sleep. To determine whether obstructive apnea in children has a tonic effect on diurnal BP, 24-hour ambulatory blood pressure was obtained from 60 children with mean age of 10.8 +/- 3.5 years. Thirty-nine children had obstructive apnea and 21 had primary snoring. Children with obstructive apnea had significantly greater mean BP variability during wakefulness and sleep, a higher night-to-day systolic BP, and a smaller nocturnal dipping of mean BP. Variability of mean arterial pressure during wakefulness was predicted by the desaturation, body mass, and arousal indices, whereas variability during sleep was predicted by apnea-hypopnea and body mass indices. Nocturnal BP dipping was predicted by the desaturation index. There were no significant differences in systolic, diastolic, or mean arterial BP during sleep between the groups. Diastolic BP during wakefulness was significantly different between the groups and correlated negatively with apnea-hypopnea index. We conclude that obstructive apnea in children is associated with 24-hour BP dysregulation and that, independent of obesity, the frequency of obstructive apnea, oxygen desaturation, and arousal contributes to abnormal BP control.

Adolescent↗

PubMed2004

Obstructive sleep apnea: MR imaging volume segmentation analysis.

PURPOSE: To retrospectively determine airway wall motion with volume segmentation of transverse cine magnetic resonance (MR) images in children with obstructive sleep apnea (OSA). MATERIALS AND METHODS: Transverse fast gradient-echo cine MR images of the hypopharynx were obtained at 1.5 T in 31 children with OSA (eight girls, 23 boys; mean age, 11.3 years) and 21 children free of airway symptoms who underwent MR imaging for other clinical indications (11 girls, 10 boys; mean age, 3.5 years). Volume segmentation with a k-means clustering algorithm was applied to transverse cine MR images to quantify airway volumes at each time. Airway wall motion for each child was described with standard deviation and range. Coefficient of variance and normalized range, which are independent of airway size, were used to compare groups (Kruskal-Wallis test). RESULTS: Plots of airway volume over time demonstrated large fluctuations during respiration in children with OSA and minimal fluctuations in controls; findings were consistent with airway distention and airway collapse in OSA. Average airway transverse volume was larger in the group with OSA than in the control group (OSA group, 2.52 mL; control group, 0.936 mL; P <.001). Mean standard deviation (OSA group, 0.840 mL; control group, 0.17 mL; P <.001) and mean range of airway cross section (OSA group, 3.552 mL; control group, 0.864 mL; P <.001) were larger in the group with OSA. Coefficient of variance (OSA group, 0.32; control group, 0.17; P <.001) and normalized range (OSA group, 1.42; control group, 0.96; P <.001) indicate statistically significant difference in airway dynamics in children with OSA. CONCLUSION: Volume segmentation of transverse cine MR images of the hypopharynx aids in quantification of increased airway wall motion in children with OSA. Transverse MR imaging demonstrates both airway distention and collapse in children with OSA.

Child↗

PubMed2004

Causes of persistent obstructive sleep apnea despite previous tonsillectomy and adenoidectomy in children with down syndrome as depicted on static and dynamic cine MRI.

OBJECTIVE: Our purpose was to evaluate the causes of persistent obstructive sleep apnea despite previous tonsillectomy and adenoidectomy in children with Down syndrome as depicted on cine MRI. MATERIALS AND METHODS: Cine MRI studies performed to evaluate persistent obstructive sleep apnea despite previous tonsillectomy and adenoidectomy were reviewed. MRI was performed under sedation and included cine MR images (fast gradient-echo) obtained in the midline sagittal plane and in the axial plane at the base of the tongue and T1-weighted spin-echo and fast spin-echo inversion recovery images in the axial and sagittal planes. Imaging parameters reviewed included static and dynamic diagnoses made, frequency of recurrence and diameter of tonsillar tissue, and tongue morphology. RESULTS: Twenty-seven patients were identified (mean age, 9.9 years). Diagnoses included glossoptosis in 17 patients (63%), hypopharyngeal collapse in six (22%), recurrent and enlarged adenoid tonsils in 17 (63%), enlarged lingual tonsils in eight (30%), and macroglossia in 20 (74%). Of the 20 patients with macroglossia, 11 (55%) had absence of the normal median sulcus and 12 (60%) had evidence of fatty infiltration of the tongue musculature. CONCLUSION: Persistent obstructive sleep apnea in children with Down syndrome who have undergone previous adenoidectomy and tonsillectomy has multiple causes. The most common causes include macroglossia, glossoptosis, recurrent enlargement of the adenoid tonsils, and enlarged lingual tonsils.

Adenoidectomy↗

PubMed2003

Upper airway motion depicted at cine MR imaging performed during sleep: comparison between young Patients with and those without obstructive sleep apnea.

PURPOSE: To compare the patterns of dynamic airway motion depicted on cine magnetic resonance (MR) images obtained during sleep between young patients with and those without obstructive sleep apnea (OSA). MATERIALS AND METHODS: Fast gradient-echo sequences were performed in the sagittal midline by using a 1.5-T unit to create cine MR images. Cine MR images obtained during sleep in 16 young patients with OSA were compared with those obtained in 16 young patients with no airway symptoms of airway disease. The nasopharynx, oropharynx, and hypopharynx were characterized in terms of airway motion as static patent (SP), dynamic patent, intermittent collapsed (IC), or static collapsed (SC); and the maximal diameter and greatest change in diameter (in millimeters) of these airways were calculated. Adenoid tonsil size and mouth position (ie, opened or closed) were determined. Differences in the frequency of MR imaging parameters in the different anatomic regions were evaluated by using Fisher exact, chi 2, and sample t tests. RESULTS: There were statistically significant differences in the following parameters between the two groups: nasopharynx SP (P <.001) and IC (P <.001); hypopharynx SP (P <.001) and IC (P <.001); and mean change in airway diameter of the nasopharynx (P <.001) and hypopharynx (P <.001). The mean adenoid tonsil size in the patients with OSA was larger (P =.006). CONCLUSION: There are significant differences in the patterns of dynamic airway motion between young patients with and those without OSA.

Adolescent↗

PubMed2003

Tracheostomy and home ventilation in children.

The last 30 years have brought a significant emphasis on home care for ventilator-dependent children. While the movement was driven by the desire to minimize healthcare costs, the advancements in medical knowledge and technology, and the change in the perception of a ventilator-dependent child have offered a fertile environment for the development of programs that support the chronic care of ventilator-dependent children at home (N. Engl. J. Med. 309(21) (1983) 1319; J. Pediatr. 106(5) (1985) 850; N. Engl. J. Med. 310(17) (1984) 1126; JAMA 258(23) (1987) 3398). In addition, the advances in medical and nursing care have led to the steady increase in the number of children with chronic respiratory failure and development of multi-disciplinary teams experienced and dedicated to the care of these children. Another trend that has also contributed to the rise in the number of pediatric patients using long-term mechanical ventilation is the parental expectation of long-term survival of their child. This parental expectation continues to grow as the effect of long-term mechanical ventilation on quality of life and longer survival becomes more evident. The primary indication for use of home mechanical ventilation is chronic respiratory failure (CRF) as indicated by hypoxemia and or hypercapnia. CRF is considered to be a condition persisting for greater than 1 month and requiring mechanical ventilation during part or all of the day to provide adequate gas exchange for the support of vital function (Chest 103(5) (1993) 1463).

Child↗

PubMed2002

Left ventricular hypertrophy and abnormal ventricular geometry in children and adolescents with obstructive sleep apnea.

Obstructive sleep apnea (OSA) has been shown to be an independent risk factor for cardiovascular disease in adults. However, there are severe limitations in the extent to which the cardiovascular consequences of OSA are being studied in children. To investigate the echocardiographic changes in children with OSA, right and left ventricular (RV, LV) dimensions and LV mass index and geometry were measured in 28 children with OSA and 19 children with primary snoring (PS). The study showed that LV mass index and relative wall thickness were greater in the OSA group compared with those with PS (p = 0.012 and p < 0.0001, respectively). An apnea-hypopnea index of more than 10 per hour was significantly associated with RV dimension above the 95th percentile (odds ratios, 6.7; 95% confidence interval, 1.4-32) and LV mass index above the 95th percentile (odds ratios, 11.2; confidence interval, 1.9-64). Abnormality of LV geometry was present in 15% of children with PS compared with 39% of children with OSA. We conclude that OSA in children is associated with increased LV mass.

Adolescent↗