NURS 251 PHARMACOLOGY Module 3

NURS 251 PHARMACOLOGY Module 3 3.1: Introduction to Cardiology Taking a Blood Pressure Blood pressure is the pressure exerted against the walls of blood vessels as blood circulates through the body. Blood pressure is measured using an instrument called a sphygmomanometer, perhaps more commonly known as the blood pressure cuff. The pressures associated are measured in units of millimeters of mercury (mm/Hg). The health care provider inflates a blood pressure cuff in order to cut off the blood flow from the brachial artery. As they release the pressure in the cuff, they are listening with a stethoscope, for the first sound, called the Korotkoff sound, meaning there is no longer enough pressure to keep all the blood from flowing. The Korotkoff sound corresponds to a numerical gauge on the sphygmomanometer and is called the systolic value (top number) of the patient’s blood pressure. The provider continues to let air out of the cuff and eventually the sounds disappear, representing that the brachial artery is now completely open. When this occurs, the numerical value on the sphygmomanometer is known as the diastolic value (bottom number) in a patient’s blood pressure. Hypertension is defined as the persistent systolic blood pressure of greater than 150mm/Hg and/or a diastolic blood pressure greater than 90mm/Hg in patients 60 years of age and older. For patients younger than 60 or those with kidney disease or diabetes, it is defined as a systolic reading greater than 140mm/Hg and diastolic greater than 90mmHg. Hypertension is often an asymptomatic disease and is also considered the most common disease state worldwide. Table 3.1 below breaks down different classifications of hypertension.