Face-mask CPAP as palliative support for diffuse tracheobronchomalacia from ring agenesis in an infant: When sleep becomes therapeutic

Abstract

Congenital absence or deficiency of tracheal rings is exceptionally rare and may cause diffuse tracheobronchomalacia (TBM) with life-threatening airway collapse. A 6-month-old girl had persistent stridor from birth, cyanotic spells during feeding, and nocturnal desaturation. Cervicothoracic CT suggested severe airway collapse, and rigid bronchoscopy showed a flattened trachea and main bronchi without visible cartilaginous rings, consistent with ring agenesis and diffuse TBM. Curative surgery was not feasible. After in-hospital titration during a nap, face-mask CPAP with heated humidification was prescribed during sleep and postprandial windows. A minimal effective pressure of 6 cmH₂O stabilized oxygenation and reduced cyanotic episodes, with good tolerance and device-recorded adherence. Despite transient clinical benefit, the infant died at one and a half years of age (18 months) due to disease progression. In extensive congenital TBM from ring agenesis not amenable to reconstruction, targeted face-mask CPAP can provide palliative/bridging support by counteracting dynamic airway collapse at times of highest vulnerability (sleep and after feeding). This case highlights practical aspects of titration, interface choice, and monitoring in infants.

1. Introduction

Congenital malformations of the trachea, though rare, can have major clinical consequences, especially when they involve the cartilaginous structure of the tracheal rings. The congenital absence of these rings is an exceptionally rare embryological developmental anomaly, responsible for severe tracheal stenosis or dynamic airway collapse [[1], [2], [3], [4]]. These anomalies often present in the neonatal period with persistent stridor, episodes of cyanosis, or recurrent respiratory infections [[1], [2], [3], [4]], and may lead to diagnostic delays or confusion with other conditions such as tracheomalacia.

Diagnosis relies on increasingly sophisticated tools such as dynamic bronchoscopy and computed tomography, while emerging techniques like optical coherence tomography (OCT) offer promising improvements in tracheal structure characterization [1]. Management is most often surgical, but this may not be feasible in diffuse or extensive forms. In such cases, continuous positive airway pressure (CPAP) therapy emerges as a relevant palliative option, particularly when anatomical anomalies preclude surgical correction [5].

Sleep represents a critical period in infants with tracheal malformations, due to the physiological decrease in pharyngeal and tracheal muscle tone that promotes airway collapse [6]. In this context, CPAP serves not only as a treatment for sleep-disordered breathing but also as a ventilatory support to stabilize respiratory status during daytime and postprandial periods—especially in infants with tracheal collapse [5,6].

We report here an exceptional case of diffuse congenital tracheobronchomalacia in a 6-month-old infant, in which CPAP played a crucial therapeutic role during both sleep and postprandial periods, in the absence of any curative surgical option.

2. Clinical case

The patient, F.H., was a full-term newborn with a birth weight of 2.3 kg and Apgar scores of 4, 5, and 7 at 1, 5, and 10 minutes, respectively. She was born to first-degree consanguineous parents, with a family history of neonatal death from respiratory distress in a sibling.

She was admitted to the neonatal intensive care unit at 22 hours of life for acute respiratory distress with inspiratory stridor present from birth. The initial clinical severity was assessed as moderate to severe. Delivered by cesarean section at 42 weeks and 2 days due to maternal preeclampsia and a scarred uterus, she presented with oxygen desaturation to 70 % under 4 L/min nasal cannula. Due to the severity of her condition, she was sedated, intubated, and mechanically ventilated, maintaining oxygen saturations between 80 and 90 % on 100 % FiO₂. Empirical antibiotic therapy was initiated with aximycine, gentamicin, and ceftriaxone. Bloodwork revealed leukocytosis at 17,400/mm³ with neutrophil predominance (13,700/mm³).

Initial chest X-rays revealed a right upper lobe opacity, followed by a basithoracic right opacity the next day, which evolved over 10 days into a bilateral alveolo-interstitial syndrome. These radiological findings were initially interpreted as infectious or ventilator-related complications. A cervico-thoraco-abdominal CT scan performed on day 28 due to persistent stridor and clinical deterioration showed no obvious tracheal anomaly but did reveal posterior-basal pulmonary consolidations, ground-glass opacities, small nodules suggestive of infection, and a partial thrombosis of the left portal vein branch.

The initial evolution was favorable with improved oxygen saturation (95–98 % on room air) and resolution of infection, allowing for extubation on day 9. However, respiratory deterioration led to reintubation for desaturation (70–80 %) and worsening biological markers (elevated CRP, thrombocytopenia), prompting a reassessment and initiation of imipenem, amikacin, and vancomycin. After a second extubation on day 14, the patient resumed feeding but remained pale (hemoglobin 8.6 g/dL), necessitating a transfusion.

One month after discharge, she was readmitted for generalized cyanosis during feeding. Echocardiography revealed a patent foramen ovale (PFO), partially explaining the desaturation episodes.

At 6 months of age, she was again hospitalized for acute respiratory distress with fever of 41 °C, grunting, coughing, rhinorrhea, signs of increased work of breathing, and desaturation to 70 %. Clinical examination revealed rhonchi on pulmonary auscultation. Initial blood tests showed hemoglobin at 11 g/dL, white blood cell count at 6710/mm³, and CRP at 5 mg/L. She was started on respiratory physiotherapy and nebulized bronchodilation with ipratropium bromide. A broad etiological investigation was initiated: stool parasitology and HIV serology were negative, rhinovirus PCR was positive. Thyroid-stimulating hormone (TSH) was within normal limits. Intact parathyroid hormone (PTH) was 44.7 pg/mL. Immunoglobulin levels were within normal range (IgG 7.25 g/L, IgA 0.63 g/L, IgM 1.46 g/L), with no indication of immunodeficiency. Total CPK was normal (91 U/L), with slightly elevated CPK-MB (63 U/L) but no clinical or echocardiographic impact.

Due to cyanotic coughing fits, oxygen therapy was resumed along with 6-hourly nebulizations. Biological markers later showed elevated WBC (17,680/mm³, neutrophils 14,490) and CRP (43.7 mg/L). Amoxicillin-clavulanic acid was initiated. Respiratory fatigue was intermittently noted, requiring supplemental oxygen.

Anthropometric measurements showed weight at 4.3 kg (−5 SD), length at 63 cm (−4 SD), and head circumference at 40 cm (−3 SD), consistent with failure to thrive. Psychomotor development was also delayed: social smiling at 4 months, no head control or sitting position.

A cervico-thoracic CT scan (Fig. 1) revealed anterior bulging of the posterior tracheal wall from C6 to T2, forming an inverted U-shaped trachea with luminal narrowing suggestive of tracheomalacia. This finding prompted a re-evaluation of the persistent stridor since birth, initially attributed to post-intubation complications.

Fig. 1.

Contrast-enhanced cervico-thoracic CT scan (axial slices with coronal and sagittal reconstructions), demonstrating anterior bulging of the posterior tracheal wall, resulting in an inverted U-shaped configuration from C6 to T2 and significant narrowing of the tracheal lumen, consistent with tracheomalacia (yellow arrows).

Rigid bronchoscopy (Fig. 2) revealed congenital absence of tracheal rings, with flattening of the trachea, mainstem bronchi, and lobar bronchi, consistent with diffuse congenital tracheobronchomalacia. Genetic testing could not be performed.

Fig. 2.

(A–C): Rigid bronchoscopy views showing an ovoid tracheal lumen with absence of visible cartilaginous rings, a compliant anterior wall, and an enlarged posterior membranous wall. The overall appearance is consistent with diffuse congenital tracheobronchomalacia.

In the absence of a curative surgical option and given the occurrence of desaturations during sleep (predominantly nocturnal, documented during nap polygraphy, Fig. 3), associated stridor, and cyanotic episodes during feeding, face-mask continuous positive airway pressure (CPAP) was initiated as a pneumatic stent to limit tracheobronchial collapse. Titration was performed in the hospital setting during a nap, with progressive trials from 4 to 6 cmH₂O to identify the minimal effective pressure. Response criteria included resolution of desaturations, reduction of stridor/inspiratory snoring, stabilization of thoracic effort, and mask leaks deemed acceptable. The effective pressure was determined to be 6 cmH₂O, which was well tolerated. The device used was a DreamStation® (Philips Respironics) in fixed CPAP mode, with a pediatric full-face mask and heated humidifier. CPAP was prescribed for all sleep periods (night and naps) as well as postprandially, corresponding to high-risk periods for collapse.

Fig. 3.

Nap polygraphy during CPAP titration. (A–D) (without CPAP): Repeated desaturations, inspiratory flow limitation (flattened CanFlow), unstable thoracic signal (THO), and snoring. (E) (CPAP 4 cmH₂O): Partial improvement: reduced frequency/amplitude of desaturations, but residual obstructive events and persistent flow limitation. (F) (CPAP 6 cmH₂O): Near-complete correction: SpO₂ stabilized (=94–95 %), regular CanFlow, stable THO, and absence of snoring → minimal effective pressure identified.

Airway stenting, including a silicone Y-shaped stent, was discussed by our multidisciplinary airway team. However, bronchoscopic findings demonstrated diffuse tracheobronchomalacia extending into both main bronchi and the lobar bronchi, together with a very small airway calibre incompatible with currently available pediatric Y-stents. In addition, stenting in non-malignant diffuse TBM is associated with a high risk of granulation, migration and repeated endoscopic interventions. For these reasons, and in accordance with pediatric airway guidelines, Y-stent placement was not considered appropriate in this infant.

Adherence monitoring (Fig. 4) over a representative 110-day period (May 30 → September 16) showed near-daily use, with an overall adherence rate of 89 % (≈98/110 days). On the “Total use” histogram, each bar represents the number of hours of daily use (vertical axis in hours); the horizontal red line indicates the adherence threshold of 4 h/night (default software setting, used here as a pediatric reference). Most nights exceeded this threshold, with several complete nights of > 7–10 h; shorter bars below the threshold corresponded to naps and prescribed postprandial sessions. Over the same period, the device summary reported a mean residual AHI of 3.6 events/h (device-derived value, adult algorithm; to be interpreted with caution in infants) and mean total leak of 36 L/min (including intentional mask leak) - findings consistent, in conjunction with clinical data, with effective ventilation and a well-fitted interface. Treatment was maintained from 6 to 18 months of age, providing approximately one year of follow-up under CPAP.

Fig. 4.

Long-term CPAP adherence. “Total use” histograms (DreamStation®) illustrating daily usage over a 110-day period (May 30 → September 16). Red line = adherence threshold set at 4 h/day. Overall adherence was 89 % (≈98/110 days), with predominantly nocturnal use and additional daytime sessions (naps/postprandial periods). For the same period, the device reported a mean residual AHI of 3.6 events/h and mean total leak of 36 L/min (including intentional leak). Values are derived from device software and should be interpreted with caution in infants.

3. Discussion

The normal trachea is composed of incomplete “C”-shaped cartilaginous rings, posteriorly open and bridged by a membranous wall. This rigid framework prevents expiratory airway collapse, with a typical cartilage-to-membrane ratio of approximately 4.5:1 [7]. Congenital absence of tracheal rings is an extremely rare anomaly of embryological development, often leading to severe tracheal stenosis or collapse, and is prone to misdiagnosis. Patients typically present with nonspecific symptoms such as stridor, apneas, cyanosis, or recurrent respiratory infections, which may be misattributed to tracheomalacia or recurrent pneumonia [[1], [2], [3], [4]].

Clinical severity depends on the extent, location, and degree of tracheal involvement. Long-segment stenosis or juxtacarinal involvement tends to be more severe. Localized forms are often isolated, whereas long or diffuse forms may be associated with esophageal atresia (EA) or tracheoesophageal fistula (TEF). Bronchoscopic examination typically reveals a soft, concentric, dynamically collapsing stenosis resembling a gastric cardia in short-ring absence. In contrast, flattened tracheal architecture with anterior collapse suggests severe tracheomalacia in extensive forms. These extended malformations do not respond to conservative management, as tracheal rigidity does not improve with age [2].

CT imaging helps assess stenosis location, length, and severity. Dynamic bronchoscopy remains essential, and emerging technologies such as optical coherence tomography (OCT) may offer future noninvasive assessment of tracheal wall structures [1]. From an embryological standpoint, multiple signaling pathways have been implicated, including Isl1–Nkx2.1, BMP, Fgf10/Shh, and inactivation of Tbx4/Tbx5, which are associated with defective tracheoesophageal separation and impaired cartilage development [[8], [9], [10], [11]]. These findings suggest that isolated short-segment absence and extensive malformations with associated anomalies may arise from distinct developmental mechanisms.

Management is often surgical. Resection-anastomosis is feasible in short segments away from the glottis or carina. Up to 50 % of the trachea may be resected in young children, beyond which the risk of anastomotic dehiscence increases. Carinal reconstructions and external tracheal stabilization may be considered in more extensive lesions. Tracheal stents may serve as a temporary bridge in acute cases but are not a definitive solution [12]. Prognosis depends on early diagnosis, associated anomalies, and surgical feasibility. Close postoperative monitoring is essential to detect restenosis or infectious complications.

A six-case series by Ma et al. [13] sheds light on this rare condition. Five infants had segmental ring absence; one had complete absence in the mid-trachea within a VACTERL syndrome. Four patients underwent successful surgery; two died—one from anastomotic rupture, the other from respiratory failure following parental refusal of surgery. One with extensive malformation required multiple stent placements. This series underscores the frequent initial misdiagnosis of tracheomalacia, as observed in our patient.

A review of seven studies including 12 patients reported by Torre et al. [1] showed that six cases had short-segment stenosis treated surgically between 4 weeks and 16 months of age. More extensive cases were associated with EA, TEF, or VACTERL. Some required tracheostomy, stents, or staged surgical interventions. Santoli [2] reported a 50 % tracheal resection, while three patients were only correctly diagnosed after failed management for presumed tracheomalacia.

A case by Angeles et al. [14] demonstrated successful surgical management of a premature newborn with focal ring absence. A complete tracheal reconstruction was achieved. Another series by Smith et al. [15] described nine children who underwent slide tracheoplasty, with a mean follow-up of 5.89 years. Only one patient required additional procedures. This confirms the effectiveness of slide tracheoplasty in selected rare malformations.

Our patient presented a diffuse absence of tracheal rings extending to the main and lobar bronchi, rendering curative surgery unfeasible. In this case, CPAP was successfully initiated to manage nocturnal desaturation, reflecting sleep-related breathing disorders exacerbated bytracheobronchomalacia. CPAP also helped stabilize respiratory status after feeding, when suction and reflux increased the risk of airway collapse.

Although tracheobronchial stents may serve as temporary support in selected older children with focal central airway obstruction, their use in infants with diffuse congenital TBM is highly restricted. According to the ERS statement on pediatric tracheobronchomalacia, Y-stents are not recommended for diffuse malacia, particularly when disease extends beyond the main bronchi, because currently available devices only splint central airways and require a minimum airway calibre [21]. Furthermore, pediatric series of airway stenting report high rates of granulation, mucus plugging, migration and repeated bronchoscopies in non-malignant, growing airways, especially in infants [12]. In our patient, the combination of very small airway calibre and diffuse malacia involving the main and lobar bronchi made Y-stent placement anatomically inappropriate. CPAP therefore represented the safest method of providing a pneumatic stent.

Several studies have shown that CPAP acts as an intraluminal stent, increasing functional residual capacity and improving forced expiratory flows in infants with tracheomalacia. It is also useful in long-term management, including in tracheostomized children when surgery is not feasible. These data support CPAP's role in delaying decompensation and maintaining functional tracheal patency.

The use of CPAP in infants under one year remains poorly documented due to technical challenges and adherence concerns. In our case, initiation at 6 months was successful thanks to a multidisciplinary sleep center approach, enhanced parental support, and controlled titration. The excellent adherence observed confirms CPAP's feasibility in this context.

A study by Sriboonyong et al. [5] involving 15 children with severe tracheobronchomalacia treated at home via tracheostomy-delivered CPAP highlights its safety and efficacy in resource-limited settings. Although our patient was not tracheostomized, this experience reinforces the value of CPAP as an effective palliative solution outside of surgery.

The effectiveness of CPAP in preventing dynamic airway collapse in infants with tracheomalacia was rigorously explored by Davis et al. [6]. In this experimental study, six infants with tracheomalacia and five controls underwent flow–volume curve measurements at different CPAP levels (0, 4, and 8 cmH₂O). CPAP significantly increased peak expiratory flows at functional residual capacity (FRC) without altering forced vital capacity (FVC). This improvement was attributed to increased lung volume (FRC), not intrinsic changes in airway mechanics. CPAP increases transpulmonary pressure, thus dilating and splinting the airway, mimicking a pneumatic brace. These results confirm its stabilizing role, especially during sleep when airway muscle tone physiologically decreases. In our case, CPAP was also beneficial after meals, when suction and swallowing increase collapse and desaturation risk. This provides a strong physiological rationale for targeted CPAP use in infants, particularly during nocturnal and postprandial vulnerability.

Our patient (6 months old) is among the youngest reported in the literature, compared with a median age of 28 months in Elmeazawy et al. [16], 33 months in Sanchez [17], 29 months in Su [8,18] months in Koenigs [19], and 8 years in Douros [20]. Unlike the male predominance reported by Elmeazawy (38 boys vs 30 girls), our female case represents a less frequent, yet well-documented presentation.

4. Conclusion

Diffuse congenital tracheobronchomalacia is a rare but severe condition that requires early and multidisciplinary management. The present case illustrates not only the diagnostic complexity of these anomalies, but also the growing interest in non-invasive strategies for inoperable forms. When initiated appropriately and supervised by a specialized sleep team, CPAP can provide significant clinical benefit even in infants, by stabilizing critical periods such as sleep and feeding. This case supports broader recognition of CPAP as a therapeutic tool in severe congenital respiratory malformations in young children.

CRediT authorship contribution statement

Abir Bouhamdi: Writing – review & editing, Writing – original draft, Methodology, Formal analysis, Data curation, Conceptualization. Yassin Chefchaou: Data curation. Nahla En-nejjari: Data curation. Meryem Benjelloun: Data curation. Sanae Labyad: Data curation. Lamiyae Senhaji: Supervision. Meryem Karhate: Supervision. Ilham Tadmouri: Supervision. Badr Alami: Supervision. Zouhayr Souirti: Supervision. Mounia Serraj: Supervision. Bouchra Amara: Supervision. Mohamed Chakib Benjelloun: Supervision. Mohammed Elbiaze: Writing – review & editing, Validation, Supervision, Conceptualization.

Consent

Informed consent was obtained from the patient's legal guardians for the publication of this clinical case.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Declaration of competing interest

The authors declare no conflicts of interest.