The effect of blood gas, hemogram, and biochemical markers on prognosis in pneumothorax cases in the emergency department

To evaluate whether admission arterial blood gas parameters (particularly lactate), complete blood count and basic biochemistry predict clinical course and outcomes in adult patients diagnosed with pneumothorax in the emergency department. Prospective cross-sectional study conducted at Pamukkale University ED between 07 Aug 2024 and 07 Feb 2025. Adults with pneumothorax meeting inclusion criteria were enrolled. Demographics, clinical/laboratory data and treatments were recorded. Outcomes were ICU admission, tube thoracostomy, length of stay and 30-day mortality. Multivariable models identified independent predictors. We included 109 patients; mean age 41.5±18.1 years, 84.4% male. Pneumothorax type: 30.3% spontaneous and 69.7% traumatic (68 blunt, 8 penetrating); concomitant hemothorax occurred in 25.7%. Mean lactate was 2.31±1.66 mmol/L. ICU admission occurred in 29.4%, ward admission in 58.7%, and tube thoracostomy in 43.1%. Mean hospital stay was 5.3±5.4 days; 30-day mortality was 1.8% (n=2). Patients receiving oxygen on arrival had longer hospital stays (6.17±5.94 vs 4.07±4.28 days; p=0.01). In multivariable analysis, lower PaO₂ independently increased the likelihood of tube thoracostomy (OR 0.966 per mmHg; p=0.019). ICU admission was inversely associated with tube placement (OR 0.235; p=0.024), reflecting clinical prioritization in severely injured patients; more ward days correlated with having a chest tube (OR 1.368; p=0.003). Independent predictors of ICU admission included pneumothorax type (trauma), need for oxygen at presentation, associated injuries/hemothorax, and deranged acid-base variables including higher lactate (all p<0.05). In ED pneumothorax, hypoxemia (low PaO₂) is a key driver of tube thoracostomy, while ICU need aligns with trauma severity and systemic compromise marked by lactate and acid-base disturbances. Early ABG and basic hematologic assessment support practical risk stratification and disposition planning.