Final answer:
A tourniquet should be applied for no more than 30 minutes to avoid tissue damage due to restricted blood flow. It's used briefly when measuring blood pressure or during certain medical procedures. Clinicians should remove or loosen it as quickly as possible.
Step-by-step explanation:
The duration for which a tourniquet should remain tied on a patient's arm is generally brief during medical procedures such as drawing blood or administering intravenous medications. For instance, when measuring blood pressure using a sphygmomanometer, the inflatable cuff acts as a tourniquet, temporarily obstructing blood flow. The clinician inflates the cuff above the patient's systolic blood pressure and then gradually deflates it while listening for Korotkoff sounds to determine blood pressure. However, in a scenario where a tourniquet is used to stop bleeding or maintain vascular access, the length of time it can be safely applied is usually limited to no more than 30 minutes. Exceeding this period risks tissue damage due to lack of blood flow. The body may respond to vessel injury with a vascular spasm that can maintain vessel constriction for up to 30 minutes but potentially for several hours. Nonetheless, professional guidelines dictate removing or loosening a tourniquet as soon as clinically possible to reduce the risk of adverse effects.