Introduction

Congenital pulmonary airway malformation (CPAM) is a rare developmental anomaly often requiring surgical intervention. Video-assisted thoracoscopic surgery (VATS) has become the preferred approach, for which effective one-lung ventilation (OLV) is crucial. In pediatric patients, the narrow airway diameter precludes the use of double-lumen tubes, making BB the mainstay for lung isolation. However, anatomical variations can sometimes challenge standard techniques. This case report describes the successful use of an innovative, individualized dual-BB strategy to achieve OLV in a child undergoing S1a segmentectomy for CPAM, after initial isolation of the right main bronchus failed. This approach highlights a valuable adaptive solution for managing complex pediatric airways.

Case report

An 11-year-old girl (height 150 cm, weight 36 kg) was admitted due to “cough for 7 days”. Physical examination on admission: BT 36.8℃, HR 82 bpm, RR 19 bpm, BP 114/69 mmHg. The patient presented with a cough and occasional nasal congestion. Auscultation revealed bilateral coarse breath sounds. Auxiliary examinations: Complete blood count: WBC 5. 06 × 10⁹/L, RBC 4. 01 × 10¹²/L, Hb 119. 00 g/L, PLT 359. 00 × 10⁹/L, lymphocytes 45. 80%, monocytes 5. 50%, neutrophils 46. 30%; Procalcitonin, ESR, CRP: normal; Routine biochemistry: liver/kidney function, cardiac enzymes, electrolytes: no abnormalities; Mycoplasma pneumoniae and Chlamydia pneumoniae IgM antibodies: negative; Immunoglobulins A/G/M: normal; IgE: normal; Coagulation test (5 items): fibrinogen 1. 82 g/L (low), other parameters normal; Urinalysis: unremarkable. ECG: Sinus arrhythmia; Non-contrast + contrast-enhanced CT findings (Fig. 1): A patchy low-density shadow in the right upper lobe with sparse lung markings. Bubble-like low-density shadows along the anteromedial border with patchy high-density opacities. A small air-containing cystic cavity ≈ 3. 6 mm in diameter with thickened walls is visible within the lesion. Tracheobronchial reconstruction: Trachea, bilateral main bronchi, and lobar/segmental bronchi are patent. Preoperative CT measurement: Right main bronchus diameter = 17 mm at 1 cm below carina (axial plane). Past history: Recurrent hospitalizations for “bronchitis” since age 2 (4–5 episodes/year), accompanied by nasal congestion and rhinorrhea. Admission diagnosis: ① Pneumonia; ② Cystic lesion, right upper lobe. After thorough discussion with thoracic surgery, surgery was planned: “Video-assisted thoracoscopic resection of right upper lobe cystic lesion under general anesthesia”.

Fig. 1
figure 1

CT showing cystic lesion in the right upper lobe

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After general anesthesia induction, a 9F BB (OD 3.0 ± 0.3 mm, Inflated balloon diameter 18 ± 5 mm, Humanwell, Yichang; Fig. 2) was placed under video laryngoscopy. An ID 6. 0 uncuffed endotracheal tube was then inserted orally. A bronchoscope was inserted through the endotracheal tube. Attempts to position the BBballoon at the right main bronchus orifice failed to achieve complete occlusion despite repeated adjustments. The BBballoon was advanced into the bronchus intermedius. Under bronchoscopic guidance, the balloon was gradually inflated with air until a complete seal was achieved, requiring a volume of 4 mL with a manometrically measured pressure of 18 cmH2O. Effective sealing was confirmed by the absence of air leak during manual lung inflation at 20 cmH2O pressure. (Fig. 3a). Under direct bronchoscopic visualization, the tip of the 5 F BB (OD 1.7 ± 0.2 mm, Inflated balloon diameter 11 ± 4 mm, Humanwell, Yichang) was slowly advanced to the orifice of the right upper lobe bronchus. By gently rotating the patient’s head to the left with slight extension, the airway axis was straightened to reduce the angulation of the right upper lobe bronchus. The blocker was then carefully rotated to adjust its orientation, allowing the balloon to be positioned precisely at the opening of the right upper lobe bronchus. The sealing efficacy was confirmed using the previously described leak test, successfully isolating the right upper lobe (Fig. 3b). Complete right lung isolation was subsequently verified through fiberoptic inspection, absence of breath sounds on auscultation, and visual confirmation of lung immobility (Fig. 3c). The BBs and endotracheal tube were then fixed in position (Fig. 3d), and satisfactory lung collapse was confirmed thoracoscopically (Fig. 4). Intraoperative monitoring included continuous electrocardiography, pulse oximetry (SpO2), invasive arterial blood pressure via a radial arterial line, cerebral oximetry, and anesthetic gas analysis. Arterial blood gas (ABG) analysis was performed 20 min after the establishment of OLV, revealing a PaO of 107 mmHg and a PaCO of 43 mmHg on FiO2 0. 5. Pressure-controlled ventilation (PCV) maintained end-tidal CO₂(PetCO₂) at 35–50 mmHg and SpO₂ >95% by adjusting respiratory rate and inspiratory pressure. The child was placed in the left lateral position. Thoracoscopic exploration revealed incomplete minor fissure, irregular visceral pleural surface of right upper lobe S1a segment, and multiple variably sized bullae on the lung surface. The S1a segmentectomy proceeded uneventfully with an estimated blood loss of approximately 5 mL. The patient maintained stable respiratory mechanics and hemodynamic parameters throughout the procedure. A second ABG analysis prior to resuming two-lung ventilation confirmed adequate gas exchange (PaO2 103 mmHg, PaCO2 45 mmHg), with no associated complications observed. OLV time: 79 min. Total surgical duration: 102 min.

Fig. 2
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Bronchial blocker (BB) placement

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Fig. 3
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Bronchial blockade achieving right lung isolation. a Occlusion of the bronchus intermedius by the first bronchial blocker (BB); b Occlusion of the right upper lobe bronchus by the second BB; c View confirming complete right lung isolation; d Final secured positions of the two BBs and the endotracheal tube

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Fig. 4
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Thoracoscopic view showing satisfactory right lung collapse following the placement of dual BBs

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Postoperatively, the endotracheal tube and BBs were removed after spontaneous breathing resumed. The child was transferred to the PACU and returned to the ward after achieving stable vital signs and full consciousness. Pathological diagnosis: CPAM (right upper lobe S1a) with mild vascular proliferation and focal hemorrhage. The patient was discharged on postoperative day 7 following clinical and imaging assessments that confirmed resolution of bronchitis and absence of other pulmonary complications.

Discussion

CPAM is the most common type of congenital pulmonary developmental anomaly, with an estimated prevalence of 1/35,000 to 1/7,200 live births and a gradually increasing trend. Its pathogenesis may involve disrupted signaling between epithelial cells and underlying mesenchymal cells during lung embryogenesis, leading to deficient normal alveoli and formation of multicystic lung masses [1]. The primary pathological features include adenomatous overgrowth of terminal bronchioles, alveolar hypoplasia, and extensive interstitial hyperplasia. These lesions are well-demarcated within the pulmonary parenchyma, typically affecting part of or an entire unilateral lung lobe. Clinical manifestations predominantly include recurrent infections and dyspnea [2]. Due to risks of cyst enlargement causing compressive symptoms, recurrent infections, and potential cyst rupture leading to pneumohemothorax—coupled with the absence of spontaneous regression during growth—surgical intervention is indicated [3] .

In pediatric patients undergoing VATS, establishing effective OLV is critical yet challenging. It is essential for achieving optimal surgical conditions through controlled lung collapse, while also protecting the dependent lung from contamination and facilitating precise manipulation in a confined operative field. In children, the narrow tracheal diameter limits double-lumen endotracheal tube options, making BB the preferred OLV tool. BBs offer advantages including operational simplicity, minimal invasiveness, and reduced disruption of respiratory physiology [4,5,6]. BB placement methods include extraluminal (outside the endotracheal tube) and intraluminal approaches. The extraluminal technique provides greater flexibility in endotracheal tube selection, requiring initial BB insertion followed by endotracheal tube placement with the BB positioned externally [7, 8]. In this case, the extraluminal approach was selected for the first BB to minimize reduction in endotracheal tube cross-sectional area and avoid interference between the bronchoscope and blocker.

The right main bronchus is anatomically anterior, closely aligned with the tracheal vertical axis, and characterized by a short, wide, steep morphology with a small tracheal bifurcation angle. Studies report right main bronchus diameters of 7. 7–9. 9 mm in children aged 9–10 years [9, 10]. Preoperative CT in this patient measured a right main bronchus diameter of 17 mm at 1 cm below the carina (axial plane). A 9F BB (OD :3.0 ± 0.3 mm, Inflated balloon diameter: 18 ± 5 mm) was initially placed extraluminally but failed to achieve complete occlusion despite repeated adjustments. Potential reasons include: measurement inaccuracies in imaging; significant interindividual variability in pediatric bronchial dimensions; and elliptical cross-sectional morphology of the right main bronchus preventing complete balloon-tissue apposition due to insufficient deformation under balloon pressure. When standard bronchial blockade fails or anatomical variations are present, anesthesiologists typically consider several alternatives: using a single-lumen endotracheal tube inserted into the main bronchus of the ventilated lung, which makes secretion clearance from the affected lung difficult and complicates the transition between two-lung and one-lung ventilation; employing a double-lumen tube, which carries an increased risk of potential injury to the glottis and trachea in pediatric patients; or relying on lung retraction or artificial pneumothorax, which increases surgical difficulty and fails to isolate the healthy lung effectively. In our approach, a 5 F BB (OD :1.7 ± 0.2 mm, Inflated balloon diameter :11 ± 4 mm) was placed intraluminally, successfully occluding the right upper lobe bronchus. Its central suction channel allowed direct aspiration of secretions from the right upper lobe while simultaneously facilitating effective collapse of the targeted lobe.

Conclusion

This case demonstrates that the dual-BB strategy represents a feasible solution for achieving lung isolation in complex pediatric airways when standard techniques fail. While our experience supports the technical reproducibility of this approach, several limitations should be acknowledged, including its single-case nature, the absence of comparative data, and the lack of long-term follow-up or pulmonary function evaluation, which precludes assessment of long-term respiratory outcomes. In addition, the reported physiological data are limited, and potential complications of dual blockers—such as airway injury, dislodgement, positioning difficulties, or extraction trauma—have not been fully explored. Successful implementation of this technique necessitates comprehensive preoperative evaluation, advanced fiberoptic bronchoscopy skills, and expertise in pediatric airway management. Therefore, we propose this method as a valuable alternative in specialized centers with appropriate technical capacity, while emphasizing that its broader application should be substantiated by further clinical evidence.