An understanding of the principles of blood pressure measurement with automated oscillometric devices (e.g., Dinamap) allows a user to realize the purpose and level of accuracy for which the equipment is designed. Good technique cells for various actions: (1) using a cuff of proper size (too large a cuff will generally work acceptably, but too small a cuff will yield erroneously high readings); (2) squeezing all of the residual air out of the cuff before applying it to the arm or leg; (3) wrapping the cuff snugly around the arm or leg; (4) instructing the patient to refrain from talking or moving and letting nothing press against the cuff during measurement; (5) keeping the cuff and heart at the same horizontal level. (6) When instrument malfunction is suspected, first checking the status of the patient (not the status of the instrument) to be sure that a clinical emergency is not causing the suspected "malfunction"; (7) repeating a reading several times when it is suspicious and, if necessary, modifying the measurement conditions by using, for example, different limbs or different cuffs until the question is resolved; and (8) remembering that a leak in the cuff, hoses, or connection can cause an unexpected malfunction.