The influence of flowrate and gas density on positive airway pressure for high flow nasal cannula applied to infant airway replicas.

High flow nasal cannula (HFNC) therapy has been previously shown to produce positive upper airway pressures in adult and child patients. This work aimed to evaluate and quantify the effects of HFNC flowrate and gas type on airway pressures measured in vitro in infant airway replicas. Ten realistic infant airway replicas, extending from nares to trachea, were connected in turn to a lung simulator and were supplied gas flows through HFNC. Air and heliox were each provided at two weight-indexed flowrates, 1 l/min/kg and 2 l/min/kg. Pressure and lung volume were continuously measured during simulated breathing. For constant simulated patient effort, no statistically significant change in tidal volume was measured between baseline and lower or higher HFNC flowrates, nor was there any significant difference in tidal volume between air and heliox. Tracheal pressure increased with increasing HFNC flow rate, and was highly variable between airway replicas. Higher pressures were measured for air versus heliox. For air supplied at 2 l/min/kg, average airway pressures in excess of 4 cm H2O were generated, with positive end-expiratory pressure (PEEP) ranging from 2.5 to nearly 12 cm H2O across the replicas. A predictive correlation for PEEP was proposed based on supplied gas density and flow velocities exiting the cannula and nares, and was able to account for a portion of variability between airway replicas (R2 = 0.913). Additionally, PEEP was well correlated with, and predictive of, expiratory peak pressure (R2 = 0.939) and average inspiratory pressure (R2 = 0.944).

Using cone beam CT to assess the upper airway after surgery in children with sleep disordered breathing symptoms and maxillary-mandibular disproportions: a clinical pilot.

BACKGROUND: The surgical excision of anatomic obstructions such as adenoids, palatine or lingual tonsils are commonly performed in children with sleep disordered breathing (SDB). Imaging studies measuring airway changes post-surgery in the SDB pediatric population are scarce, rarely addresses the nasal cavity, and are based on global measures (e.g. volume) that do not represent the complexity of the upper airway anatomy. The purpose of this pilot is to test the feasibility in using cone beam CT (CBCT) to analyze the nasal and pharyngeal airway space post-surgery using meaningful methods of analyses, and correlating imaging findings with clinical outcomes in children with SDB symptoms and maxillary-mandibular disproportion. METHODS: Twelve non-syndromic children with SDB symptoms and jaw disproportions were evaluated by interdisciplinary airway team before and after upper airway surgery. CBCT and OSA-18 quality of life questionnaire pre and post-operatively were completed. Conventional and new airway variables were measured based on 3D models of the upper airways and correlated with OSA-18. Conventional measures include volume, surface area, and cross-sectional area. New airway measures include constriction and patency; point-based analyses. RESULTS: Eight females and four males were 8.8 ± 2 years with mean BMI of 18.7 ± 3. OSA-18 improved, median (lower quartile-upper quartile) from 64.2 (54.7-79.5) to 37.6 (28.7-43) postoperatively, p < 0.001. The median of all airway measures improved however with very wide range. Subjects with the smallest amounts of constriction relief and/or gain in airway patency presented with least improvement in OSA-18. New airway measures show strong correlation with changes in OSA-18 (ρ = 0.44 to 0.71) whereas conventional measures showed very weak correlation (ρ = -0.04 to 0.37). CONCLUSIONS: Using point-based analyses, new airway measures better explained changes in clinical symptoms compared to conventional measures. Airway patency gained by at least 150% and constriction relief by at least 15% showed marked improvement in OSA-18 by 40-55%, after surgery in the tested cohort.

Adenovirus necrotizing hepatitis complicating atypical teratoid rhabdoid tumor.

Adenovirus-induced fulminant hepatitis is rare. It has been reported in children with primary immunodeficiency, following transplantation or while receiving chemotherapy for hematological malignancy. We present the case of an infant recovering from chemotherapy for atypical teratoid rhabdoid tumor (ATRT) in whom a diagnosis of hepatic necrosis due to adenovirus was made.

Evaluation of sevoflurane as an anesthetic agent for voiding cystourethrography in pediatric patients.

BACKGROUND: Sevoflurane anesthetic has recently been administered by anesthesiologists during voiding cystourethrograms in a centre where radiologists are not permitted to deliver pediatric sedation. OBJECTIVE: To determine whether sevoflurane is a satisfactory anesthetic agent for voiding cystourethrography in children. METHODS: Records of children undergoing voiding cystourethrogram while they were under sevoflurane were reviewed for anesthetic adverse effects and diagnostic quality of the cystourethrogram. The occurrence of on-table voiding and post-void residual bladder volume were documented and compared with an age- and sex-matched control group of children undergoing unsedated voiding cystourethrography. The caregivers were surveyed regarding the anesthetic experience. RESULTS: A total of 91 children underwent sevoflurane voiding cystourethrography; there were no adverse cardiorespiratory events. Voiding was observed in 96%, with residual bladder volumes minimal in 38%, moderate in 32%, and large in 28% of anesthetized children, not significantly different from the control group. Vesicoureteral reflux was observed in 53% of examinations under sevoflurane. When children with a previous history of reflux or voiding cystourethrography were excluded in a comparison with age- and sex-matched controls, vesicoureteral reflux was observed in 38% of studies under sevoflurane and in 44% of studies in the control group, P = .69; 85% of caregivers of children with prior unsedated voiding cystourethrography found voiding cystourethrography with sevoflurane easier than without sevoflurane; 89% thought the anesthetic experience reduced their child's anxiety towards medical procedures. CONCLUSION: No adverse events or effects on diagnostic quality of the pediatric voiding cystourethrogram were encountered when using sevoflurane. The majority of surveyed caregivers thought that anesthesia made voiding cystourethrography an easier experience for their child.

The rapid prototyping of anatomic models in pulmonary atresia.

OBJECTIVE: The goal of this study was to assess the utility and accuracy of solid anatomic models constructed with rapid prototyping technology for surgical planning in patients with pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries. METHODS: In 6 patients with pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries, anatomic models of the pulmonary vasculature were rapid prototyped from computed tomographic angiographic data. The surgeons used the models for preoperative and intraoperative planning. The models' accuracy and utility were assessed with a postoperative questionnaire completed by the surgeons. An independent cardiac radiologist also assessed each model for accuracy of major aortopulmonary collateral artery origin, course, and caliber relative to conventional angiography. RESULTS: Of the major aortopulmonary collateral arteries identified during surgery and conventional angiography, 96% and 93%, respectively, were accurately represented by the models. The surgeons found the models to be very useful in visualizing the vascular anatomy. CONCLUSION: This study presents the novel vascular application of rapid prototyping to pediatric congenital heart disease. Anatomic models are an intuitive means of communicating complex imaging data, such as the pulmonary vascular tree, which can be referenced intraoperatively.

Antenatal diagnosis and successful surgical removal of a large right ventricular fibroma.

Congenital cardiac tumors are very rare and fibromas are the second most common type. Fibromas are benign tumors, but they have potentially serious complications. Their antenatal diagnosis is infrequently reported in the literature, and the management of these tumors is a source of controversy. We report the case of a rare form of right ventricular free wall fibroma. Antenatal diagnosis was made at 36 weeks of gestation, with subsequent successful resection at 2 weeks of age. A brief review of the literature focuses on the diagnostic approach and the clinical and surgical management of congenital cardiac fibromas.