You are working in a tertiary care hospital when a 23 year-old male presents to your emergency department after being physically assaulted. He suffered a head injury as well as multiple stab wounds to the chest. His GCS was 4 on presentation, and there was no pneumothorax on initial chest X-ray. After you perform RSI, the patient was found to have a small pneumothorax on repeat chest X-ray. Patient is clinically stable, and you consider observation. What factor in his clinical presentation increases the chance of observation failure?