What is a straight catheter used for?

A straight catheter is specifically designed for single-use drainage of the bladder. It is inserted to relieve urinary retention or to obtain a sterile urine sample. Once the bladder has been drained, the catheter is removed. This temporary type of catheterization does not provide continuous drainage, which distinguishes it from other types of catheters such as indwelling or Foley catheters that are designed for long-term drainage.

Although the other options mention valid uses of different types of catheters or procedures, they do not accurately reflect the function of a straight catheter. Continuous drainage of the bladder applies to indwelling catheters, while medication delivery involves specialized catheters that are generally designed for that purpose. Monitoring bladder pressure typically requires a different setup, often with specialized catheters used in urodynamic studies rather than a straight catheter. Therefore, the distinct characteristic of the straight catheter being a single-use device for immediate bladder drainage makes it particularly suited for the purpose described in the answer.