Pneumothorax - In a pneumothorax, air collects in the pleural cavity. It may be caused by trauma to the chest, chest surgery, and COPD among other causes. When a pneumothorax is small, it may simply be observed to see if the air is reabsorbed.
This ratio is determined by dividing the HDL cholesterol into the total cholesterol. If a person has a total cholesterol of 200 mg/dL and an HDL cholesterol of 40 mg/dL, his or her total/HDL cholesterol ratio would be 5:1. The goal is to keep this ratio below 5:1, with the ideal being below 3.5:1.his ratio is determined by dividing the HDL cholesterol into the total cholesterol. If a person has a total cholesterol of 200 mg/dL and an HDL cholesterol of 40 mg/dL, his or her total/HDL cholesterol ratio would be 5:1. The goal is to keep this ratio below 5:1, with the ideal being below 3.5:1.
Total cholesterol is defined as the sum of HDL, LDL, and VLDL. Usually, only the total, HDL, and triglycerides are measured. For cost reasons, the VLDL is usually estimated as one-fifth of the triglycerides and the LDL is estimated using the Friedewald formula (or a variant): estimated LDL = [total cholesterol] â [total HDL] â [estimated VLDL].