[Two Cases of Tension Pneumothorax during Posterior Spinal Fusion -Diagnosis and Decision on Emergency Drainage-].

We experienced two cases of tension pneumothorax during posterior spinal fusion. Case 1 : A 67-year-old female underwent posterior thoracic-lumbar spinal fusion. One hour after the operation had started, a sudden elevation of airway pressure and decreased Pa02 were observed. Then occasional decrease in blood pressure, tachycardia, and premature ventricular contractions followed. SpO2 re- mained stable throughout the surgery. Case 2 : A 57-year-old female underwent posterior thoracic-lumbar spinal fusion. During the surgical pro- cedure, a sudden decrease in SpO₂ accompanied by an air leak from pleura occurred. No remarkable change was observed in hemodynamics. Immediately after the operation had finished, chest X-ray on supine position revealed tension pneumotho- rax in both cases. Patients were extubated after effec- tive lung expansion by insertion of thoracic drainage tube. Tension pneumothorax is a potentially lethal compli- cation during anesthesia, resulting in cardiac arrest Though rapid diagnosis is crucial, physical examination and assessment are limited in patients on prone posi- tion. The possibility must be considered that several conditions as increased airway pressure, impaired oxy- genation and hemodynamics suggest tension pneumo- thorax. Image diagnosis using radiography or ultra- sound can be of value. If once patient on prone position develops cardiac arrest, resuscitation is extremely difficult Emergency drainage should be considered in case of highly im- paired hemodynamics.