Final answer:
Removing an outer sweater when measuring blood pressure helps to prevent falsely high readings and ensures the Korotkoff sounds are not muffled, which are essential for accurate systolic and diastolic pressure readings.
Step-by-step explanation:
The reason for removing the outer sweater before measuring blood pressure is primarily to prevent falsely high readings and to eliminate any muffling of the Korotkoff sounds.
These sounds are critical in determining the systolic and diastolic pressures, as they mark the moments when blood flow starts and stops being obstructed by the cuff's pressure.
Proper placement and inflation of the blood pressure cuff, without any intervening fabric, help ensure an accurate reading. Additionally, doing so can also make the patient more comfortable and ensure proper cuff application, although comfort and application ease are generally secondary reasons to the primary goal of accuracy.