What is the main difference between auscultatory and oscillometric BP devices?

• A. Auscultatory devices use Korotkoff sounds with a stethoscope; oscillometric devices detect cuff pressure oscillations and estimate SBP/DBP via algorithms.
• B. Auscultatory devices rely on pulse oximetry; oscillometric devices rely on auscultation.
• C. Auscultatory devices measure MAP directly; oscillometric devices do not.
• D. Auscultatory devices require finger pulse checks; oscillometric do not.

Answer: (B)

The main difference is how the device determines the pressure. In auscultatory measurement, you inflate the cuff and slowly deflate while listening with a stethoscope for Korotkoff sounds; the first sound marks systolic BP and when the sounds disappear marks diastolic BP. This method relies on audible arterial sounds and human listening.

In oscillometric measurement, the cuff is inflated and deflated while the device detects small oscillations in cuff pressure caused by each heartbeat. The device uses algorithms to interpret these oscillations to estimate systolic and diastolic pressures (and often mean arterial pressure). It's automated and doesn’t require a stethoscope.

The statement that auscultatory devices rely on pulse oximetry is not correct, since pulse oximetry measures oxygen saturation, not blood pressure.