Final answer:
For a patient with shortness of breath, the supine position should generally be avoided when preparing for an EKG. Instead, a semi-upright position is usually recommended to ease breathing. Standing positions or other strenuous postures are also not appropriate for an EKG in patients with respiratory issues.
Step-by-step explanation:
The medical assistant is preparing a patient who has shortness of breath for an EKG, and it is important to choose the correct position for the patient to ensure comfort and accuracy of the reading. For a patient with shortness of breath, the position that is generally not recommended is the supine position, where the patient is lying flat on their back. This position can sometimes exacerbate breathing difficulties, especially in patients with respiratory issues like pneumonia, as it can limit the expansion of the lungs and can increase pressure on the chest. The preferred positions might include sitting up or in a semi-reclined position to help ease the breathing.
A standing position with extended upper limbs out at a ninety-degree angle and lower limbs in a wide stance is typically not used for an EKG and could be challenging for a patient with shortness of breath. Therefore, position b and d from the options provided are not appropriate for an EKG in a patient with shortness of breath. Position c, which is the supine position with the limbs at the sides, should be avoided in patients with breathing difficulties. Instead, a semi-upright position like Fowler's or semi-Fowler's can assist in easier breathing during the EKG.