What is the appropriate management for a patient presenting with malacic changes?

Management of Malacic Changes (Tracheobronchomalacia)

For patients with symptomatic airway malacia, use positive end-expiratory pressure (PEEP) to stent the airways open during mechanical ventilation, and consider unsedated dynamic CT or MRI imaging as an alternative to bronchoscopy when anesthesia risks are prohibitive. 1

Diagnostic Approach

Initial Evaluation

• Bronchoscopy remains the gold standard for diagnosing tracheobronchomalacia (TBM), defining malacia as >50% airway collapse from inspiration to expiration 1
• Dynamic imaging (CT or MRI) should be considered when bronchoscopy carries excessive anesthesia risk, is not feasible, or subspecialist availability is limited 1
• Free-breathing cine CT demonstrates 96% sensitivity, 97% specificity, and 97% accuracy compared to bronchoscopy for diagnosing tracheomalacia 1

Imaging Considerations

• Dynamic CT requires radiation exposure (0.75-1.96 mSv), though doses are designed for pediatric patients 1
• CT may underestimate severity compared to bronchography, correctly identifying only 10 of 16 cases of tracheomalacia and 14 of 28 cases of bronchomalacia in one prospective study 1
• Respiratory-gated MRI shows moderate correlation with bronchoscopy and avoids radiation exposure 1

Medical Management

Mechanical Ventilation Strategies

• Apply PEEP at 5-8 cmH₂O to stent malacic airways open; higher PEEP may be necessary based on disease severity 1
• Use PEEP specifically in obstructive airway disease when air-trapping is present and to facilitate triggering 1
• Target patient-ventilator synchrony and monitor pressure-time and flow-time scalars 1
• Keep plateau pressure ≤28-32 cmH₂O with increased chest wall elastance, ≤30 cmH₂O in obstructive airway disease 1

Conservative Measures

• Maintain head of bed elevated 30-45° to optimize airway patency 1
• Use humidification for all mechanically ventilated patients 1
• Perform endotracheal suctioning only on indication, not routinely 1

Interventional Management

Airway Stenting Indications

• Stent placement is indicated for: extrinsic stenosis with luminal disorders, complex inoperable strictures, tracheobronchial malacia, and central airway fistulae 1
• Stent length should exceed stenosis margins; external diameter should be slightly larger than normal airway diameter 1
• Symptom relief and quality of life improvement achieved in the majority of patients with stent placement 1

Stent-Related Considerations

• Avoid uncovered metallic stents when tissue ingrowth may cause obstruction or if stent removal is anticipated 1
• Complications occur in <20% of cases, including displacement, mucus impaction, granuloma formation, and re-obstruction 1
• Stent insertion requires specialized training: 10 supervised procedures before independent practice, 5-10 procedures/year to maintain competence 1

Surgical Options for Refractory Cases

• Posterior tracheobronchial splinting with polypropylene mesh (Marlex) permanently prevents expiratory collapse in severe cases, with mean FEV₁ rising from 51% to 73% predicted (p=0.009) 2
• External bioresorbable plates can treat refractory localized malacia through transcervical approach under endoscopic guidance 3
• Complete splinting of all malacic central airways provides relief of dyspnea, cough, and secretion retention 2

Prognostic Implications

Morbidity and Mortality

• Untreated TBM is associated with significant morbidity including increased risk of death before hospital discharge, tracheostomy requirement, and need for home pulmonary vasodilator therapy 1
• Large airway malacia (>50% decrease in cross-sectional area) correlates with worse BPD-related outcomes 1

Mechanism of Collapse

• Snap-through instability is the mechanism for life-threatening collapse, occurring when cartilage ring properties are critically reduced 4
• Even 1 cm segments with critical property reduction can precipitate complete airway collapse 4
• Increased tracheal diameter and malacic segment length coupled with decreased cartilage/fibrous tissue properties increase collapse risk 4

Critical Pitfalls to Avoid

• Never use endovascular stenting alone without surgical ligament release in cases with extrinsic compression—this will fail due to persistent compression causing stent complications 1
• Avoid high FiO₂ (>0.8) as it worsens atelectasis formation; use FiO₂ <0.4 when clinically appropriate 5
• Do not rely solely on static imaging—malacia is state-dependent and varies with patient agitation and respiratory distress 1
• Ensure complete splinting of all malacic segments during surgical intervention, as incomplete treatment leads to poor outcomes 2