On an erect chest X-ray, a hemothorax is suggested by blunting of the costophrenic angle or partial or complete opacification of the affected half of the thorax. On a supine film the blood tends to layer in the pleural space, but can be appreciated as a haziness of one half of the thorax relative to the other. A small hemothorax may be missed on a chest X-ray as several hundred milliliters of blood can be hidden by the diaphragm and abdominal viscera on an erect film. Supine X-rays are even less sensitive and as much as one liter of blood can be missed on a supine film. Other methods
Ultrasonography may be used to detect hemothorax and other pleural effusions. This technique is of particular use in the critical care and trauma settings as it provides rapid, reliable results at the bedside. Ultrasound is more sensitive than chest x-ray in detecting hemothorax. Ultrasound can cause issues in people who are morbidly obese or have subcutaneous emphysema. When CT is unavailable in the current setting or the person cannot be moved to the scan, ultrasound is used.Computed tomography (CT or CAT) scans may be useful for diagnosing retained hemothorax as this form of imaging can detect much smaller amounts of fluid than a plain chest X-ray.
Tropicamide/hydroxyamfetamine (trade name Paremyd) is a combination drug used as an ophthalmic solution to induce mydriasis. It consists of:
Tropicamide (0.25%), an anticholinergic drug
Hydroxyamfetamine (norpholedrine, 1%), a sympathomimetic drug


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