Using a Poor Man's Doppler with the femoral pulse, a 'Present' result indicates BP is at least how many mmHg?

Using a Poor Man's Doppler with the femoral pulse, a 'Present' result indicates BP is at least how many mmHg?

• A. 40 mmHg
• B. 60 mmHg
• C. 80 mmHg
• D. 100 mmHg

Answer: (B)

The concept being tested is how a Poor Man’s Doppler estimates systolic blood pressure by using a Doppler signal to mark the pressure at which flow first returns as you deflate the cuff. When you hear a Doppler signal (“Present”) at a certain cuff pressure, that pressure is a lower bound for the systolic blood pressure—the artery begins to allow forward flow when the cuff pressure drops to roughly the systolic level. If the signal is audible at 60 mmHg, the systolic blood pressure must be at least 60 mmHg. It could be equal to or higher than that, but it cannot be lower. The other options would imply the signal would have appeared only at those higher or lower pressures, which isn’t the information given by a “Present” result at 60 mmHg. This method provides a rough, not perfectly precise, estimate and is typically used to obtain a quick SBP when auscultation is impractical.

The concept being tested is how a Poor Man’s Doppler estimates systolic blood pressure by using a Doppler signal to mark the pressure at which flow first returns as you deflate the cuff. When you hear a Doppler signal (“Present”) at a certain cuff pressure, that pressure is a lower bound for the systolic blood pressure—the artery begins to allow forward flow when the cuff pressure drops to roughly the systolic level.

If the signal is audible at 60 mmHg, the systolic blood pressure must be at least 60 mmHg. It could be equal to or higher than that, but it cannot be lower. The other options would imply the signal would have appeared only at those higher or lower pressures, which isn’t the information given by a “Present” result at 60 mmHg. This method provides a rough, not perfectly precise, estimate and is typically used to obtain a quick SBP when auscultation is impractical.