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.