Flow dynamics in pediatric rigid bronchoscopes using computer-aided design modeling software

Anesthesia for thoracic surgery in infants and children

The management of infants and children presenting for thoracic surgery poses a variety of challenges for anesthesiologists. A thorough understanding of the implications of developmental changes in cardiopulmonary anatomy and physiology, associated comorbid conditions, and the proposed surgical intervention is essential in order to provide safe and effective clinical care. This narrative review discusses the perioperative anesthetic management of pediatric patients undergoing noncardiac thoracic surgery, beginning with the preoperative assessment. The considerations for the implementation and management of one-lung ventilation (OLV) will be reviewed, and as will the anesthetic implications of different surgical procedures including bronchoscopy, mediastinoscopy, thoracotomy, and thoracoscopy. We will also discuss pediatric-specific disease processes presenting in neonates, infants, and children, with an emphasis on those with unique impact on anesthetic management.

Effect of Heliox on Respiratory Outcomes during Rigid Bronchoscopy in Term Lambs

Objective To (1) compare physiologic changes during rigid bronchoscopy during spontaneous and mechanical ventilation and (2) evaluate the efficacy of a helium-oxygen (heliox) gas mixture as compared with room air during rigid bronchoscopy. Study Design Crossover animal study evaluating physiologic parameters during rigid bronchoscopy. Outcomes were compared with predicted computational fluid analysis. Setting Simulated ventilation via computational fluid dynamics analysis and term lambs undergoing rigid bronchoscopy. Methods Respiratory and physiologic outcomes were analyzed in a lamb model simulating bronchoscopy during foreign body aspiration to compare heliox with room air. The main outcome measures were blood oxygen saturation, heart rate, blood pressure, partial pressure of oxygen, and partial pressure of carbon dioxide. Computational fluid dynamics analysis was performed with SOLIDWORKS within a rigid pediatric bronchoscope during simulated ventilation comparing heliox with room air. Results For room air, lambs desaturated within 3 minutes during mechanical ventilation versus normal oxygen saturation during spontaneous ventilation ( P = .01). No improvement in respiratory outcomes was seen between heliox and room air during mechanical ventilation. Computational fluid dynamics analysis demonstrates increased turbulence within size 3.5 bronchoscopes when comparing heliox and room air. Meaningful comparisons could not be made due to the intolerance of the lambs to heliox in vivo. Conclusion During mechanical ventilation on room air, lambs desaturate more quickly during rigid bronchoscopy on settings that should be adequate. Heliox does not improve ventilation during rigid bronchoscopy.

Predictors of complicated airway foreign body extraction

OBJECTIVES

To evaluate outcomes of foreign body aspiration (FBA) and to investigate surgeon and hospital volume as risk factors for a complicated course.

STUDY DESIGN

Retrospective case series.

METHODS

Children with FBA in a multihospital network were identified from January 2005 to September 2015. Demographic information, surgeon, and hospital location were reviewed. Mean operative time and hospital length of stay were recorded. Cases requiring intensive care unit admission, hospital stay greater than 24 hours, need for more than one bronchoscopy, operative time greater than 1 hour, or death were considered "complicated."

RESULTS

A total of 450 cases of airway foreign body extraction were performed. Patient ages ranged from 0.6 to 18.8 years, with a median age of 1.9 years. Bronchoscopy with foreign body extraction was performed by 55 different surgeons at 11 different facilities. There were one to 24 surgeons for each facility, with an average number of 5.4 surgeons per facility. A total of 88 (19.6%) cases were considered complicated, including five (1.1%) deaths. Increased rates of complications were seen with unwitnessed aspiration (P = 0.008) and hyperlucency (P < 0.001) or infiltrates (P = 0.001) on chest radiographs. No significant association was found between surgeon type or facility as related to a complicated case.

CONCLUSIONS

Unwitnessed aspiration events and abnormalities on chest radiograph may be associated with a more complicated course in children with FBA. This multihospital study identified a low number of procedures by many surgeons; however, surgeon and hospital volume did not significantly correlate with higher complication rates.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:490-495, 2018.