Early Ultrasound Diagnosis of Post-Operative Microaspiration and Pneumonia (Case Report)

Aspiration-related complications remain one of the most significant causes of early postoperative pneumonia, and microaspiration often occurs without symptoms and is not recognized at an early stage. The sensitivity of chest X-ray and CT (computed tomography) for the earliest changes is limited, creating a diagnostic «gap» in which lung ultrasound (LUS) may play a key role. 
Patient case presentation. A 62-year-old patient with class III obesity (body mass index [BMI] 46.5 kg/m²), ASA class III, and a significant oncologic history experienced a prolonged (8-hour) neurosurgical procedure in the prone position. In the early postoperative period, after reintubation, she developed severe hypoxemia in the absence of specific changes on chest radiography or chest CT, while laboratory inflammatory markers were consistent with a nonspecific postoperative response. Lung ultrasound revealed a pattern atypical for atelectasis: multiple small (up to 1.5 cm²) subpleural consolidations scattered predominantly in the right lung, including nondependent areas, in the environment of preserved aeration of the surrounding tissue and a low lung ultrasound score. 
Diagnostic assessment and interventions. The initial impression of atelectasis was revised in favor of early aspiration pneumonia, despite a «negative» CT scan. On serial ultrasound, there was a rapid increase in the number and size of subpleural consolidations, a rise in the total ultrasound score from 7 to 17, and the appearance of a right-sided pleural effusion, which prompted repeat CT and escalation of respiratory and antibiotic therapy. The repeat CT confirmed multiple areas of consolidation and hydrothorax; aspiration pneumonia was ultimately confirmed by bronchoscopy and bronchoalveolar lavage culture, which grew polymicrobial oral flora. 
Conclusion. In the presented case, the specific lung ultrasound pattern and its progression preceded radiographic changes and made it possible to promptly suspect postoperative microaspiration as the cause of severe respiratory failure. Routine use of standardized lung ultrasound screening in high-risk patients may become a promising tool for the very early diagnosis of microaspiration, expediting the initiation of antimicrobial therapy. 

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