Discussion
This is the first report in literature on performing FE-NIV assessment in the whole approachable AE tract in infants with sBPD. FE-NIV is a practical and well-tolerated modality even in cardiopulmonary compromised infants. In this study, all infants received complete FE assessments, and each assessment was safely accomplished in no more than seven minutes. Transient desaturation or bradycardia that occurred were all resolved in less than two minutes of applying this NIV maneuvers.
BPD is a clinically challenging condition. Many AE tract pathologies that resulted in lumen narrowing or incompetency may be frequently undiagnosed or misdiagnosed due to poor diagnostic value of indirect radiographic images or intolerance to direct FE procedures without appropriate support. Airway tissue of premature infants are particularly vulnerable be injury as they are fragile and compliant.19,20 Since birth, their AE tracts bore frequent invasive processes such as intubations, suctioning, infections and barotrauma of prolonged PPV during their complicated and lengthy hospitalizations. These iatrogenic damages might result in tissue fibrosis, lumen stenosis and structural weakness.21-23In addition, infants with sBPD also encounter recurrent complications such as sepsis, cyanotic episodes, apnea and difficulty weaning. Therefore, they are best assessed and managed by a multidisciplinary team specializing in comprehensive care of the complex disorders.
For infants with invasive airways (ET or tracheostomy tube), we started the FE assessment through the artificial lumens evaluating tissue-condition around the tube’s tip, where the most iatrogenic trauma rise. By manipulating FE and invasive airway, we imitate the dynamic ET tip motion and the suction catheter against the mucosal wall of tracheobronchial lumens in vivo. The ET or FE tips might embed into a granuloma, against the main carina, or even block a bronchial branch. Additionally, the tip of suction catheter might repeatedly striking against the bifurcations of a branch and resulted in granulation formations. All of these causes of traumatic striking might be ignored after extubation. For infants without ET or after extubation, comprehensive assessment with FE-NIV began from the nostrils down to the all-approachable bronchi, esophagus, and stomach were performed with increased focus around the hypopharynx, larynx and supra-stomy region where majority of ET, tracheostomy tube, suctioning and feeding tube related injuries might exist.24-26 Kurachek, et al.22 reported that that upper airway lesions like laryngomalacia, subglottic stenosis, TM, BM or tracheobronchial malacia are the leading causes of extubation failure in pediatric patients. In this study, majority of infants with sBPD (38/42, 90.5%) had AE pathologies detected by FE-NIV. These findings highlight the importance of performing precise AE tracts evaluation.
Failure of extubation or weaning respiratory support in patients with sBPD due to pathologies involving AE tract have been well reported in the literature.23,27-29 In our study, positive rate of 90.5% (38/42) was higher than rate of 74.0% (20/27) from previous study by Hysinger4 in which only airway pathologies were identified. Utilizing the novel FE-NIV approach, we were safely take time and able to detailedly examined AE regions including pharyngolarynx, upper trachea and esophagus, and thus, yielded more pathologic findings. These findings allowed us to further adjust and formulate appropriate and individualized treatment strategies for lesions encompassing not only the airway tracts, but also the esophageal portions.
Consequent changes of respiratory cares and medication management were adjustment. For symptomatic or refractory airway lesions such as severe granulations, stenosis and malacia, we were capable of providing effective therapeutic interventions through the FE-NIV procedure,15,30 including laser ablation for granulations and balloon dilatation for lumen stenoses. Additionally, in selected infants of severe airway malacia with frequent life-threatening episodes and failed to achieve satisfactory response to such management, we were able to performed stent placements16,30 over the affected sites with aid of FE-NIV, thus forestalling the need of more invasive surgical approach. In this study, surgeries of tracheostomy and gastric fundoplication were reserved for severe, refractory subglottic stenosis and GERD, respectively.
Performing FE-NIV approach for assessment of sBPD infants provides several advantages. First, it is a simple and practical skill that obviates the need for artificial airway devices such as face-mask, ventilation bag, laryngeal airway mask, ET, ventilator, or equipment as HFNC that is cost-effective and applicable in resource-limited situations. Compare to the HFNC, this NIV may be better in less oxygen flow needed, interface near the larynx, and provide controllable PPV for effects of splinting airway and oxygenation. Second, in the “PhO2”, the ventilation interface locates near the larynx which has less death space and it functioning likes the physiology of “apneic oxygenation”31,32 can prolong duration of safe oxygen saturation. Third, due to less airway devices used, workspace for FE handling and manipulation is less occluded, allowing for smoother procedure, careful measurement and yield more comprehensive pathologies. Fourth, it can provide direct and dynamic visual evidence-base information that is valuable to formulate clinical decisions for individualized management. Fifth, addition of SPI and AC, it can safely support the PPV, provide a less hurried approach, improve the FE assessment as well as the more invasive therapeutic procedures, even in cardiopulmonary compromised infants.15-17,29
There are several limitations presented in this study. 1) Due to retrospective nature, it was difficult to clarify the complex factors contributed to these pathologies, especially for infants who were transferred to our hospital relatively late in their clinical courses. 2) No bronchoalveolar lavage was performed during FE that was due to it could easily be achieved by direct suction from invasive airway and also concerned about tracheobronchial colonization in these infants. As result, we preferred using FE with no inner channel. 3) The sample size was small and the FE-NIV used in the study was single-center based. Future multicenter studies of the FE-NIV assessment in whole AE tract may be needed to more clarify the issues.