Blood Pressure

Blood pressure is the force that blood exerts on vessel walls, as it circulates throughout the body to deliver nutrients and oxygen to tissues and organs. When measuring your patient's blood pressure, you will follow the steps of the Clinical Judgment Measurement Model, or CJMM, to make clinical decisions about patient care.

Okay, let's review the physiological regulation of blood pressure. First, when the heart contracts and pumps blood through the body during systole, the blood pressure rises. On the other hand, when the heart relaxes and refills with blood during diastole, the blood pressure decreases.

In addition to the heart, there are other internal factors that regulate blood pressure. The elastic arteries maintain blood pressure and help propel blood forward through the body by expanding and recoiling with each heartbeat. In addition, the autonomic nervous system can increase the blood pressure by increasing the heart rate and by causing vasoconstriction, where the arteries constrict, or it can decrease blood pressure by lowering the heart rate and by causing vasodilation, where the arteries relax.

Blood pressure is also influenced by hormones, like the renin-angiotensin-aldosterone system, which increases blood pressure by causing vasoconstriction and increasing the circulating blood volume; and through antidiuretic hormone, which also increases blood volume.

There are also some external factors that can increase blood pressure, too, like aging, which causes arteries to become stiffer and less compliant; and emotions, like anger and pain, which can stimulate the autonomic nervous system.

Now, blood pressure is measured in millimeters of mercury, or mm Hg for short; and is written as a fraction, like 118 over 72. In this example, 118 represents the systolic, or peak pressure in the arteries during systole; whereas 72 represents the diastolic, or lowest pressure in the arteries during diastole. Blood pressure can be measured manually, electronically, or even palpated from the brachial artery in the upper arm.

Alright, when assessing your patient's blood pressure, you will use the Clinical Judgment Measurement Model to gather and recognize important cues, including the blood pressure reading, measurement site, equipment used, as well as the patient's age, health conditions, and baseline blood pressure.

In addition, you will recognize other objective cues associated with alterations in blood pressure like cool, clammy skin or facial redness; as well as subjective cues like dizziness, blurred vision, or headache.

Next, you will analyze the relationship between the cues and link them to your patient's history and clinical presentation. For example, you'll consider whether your patient's report of blurred vision and headache are consistent with a high blood pressure reading, or if tachycardia and light headedness are consistent with hypotension.

Then, you will determine a priority hypothesis related to altered blood pressure, such as hypertension, hypotension, or orthostatic hypotension. You will rank the hypotheses by considering whether the findings are potentially life-threatening, like extremely high or low blood pressure; or an immediate concern, like chronic hypertension.

Based on this information, you will address the most serious hypothesis first, and then generate solutions, such as "My patient's blood pressure will return to the expected range within two hours of treatment."

Okay, once you have generated solutions, you will take action to implement them. For patients with hypertension, administer the prescribed antihypertensive medications and provide a calm, restful environment. For patients with hypotension, administer the prescribed IV fluids and oxygen, as well as blood products if the hypotension is from blood loss. Lastly, for orthostatic hypotension, encourage your patient to increase fluid intake, and change positions slowly to prevent falls.

Lastly, you will evaluate whether the expected outcomes have been met by reassessing your patient's blood pressure, to determine whether your patient's condition is improving, declining, or remains unchanged. If your patient's condition is declining or hasn't changed, you will need to revise the plan of care accordingly and take additional actions to guide care.

Alright, as a quick recap... Blood pressure is the force blood exerts on vessel walls, as it circulates throughout the body to deliver nutrients and oxygen to the tissues and organs. When measuring your patient's blood pressure, you will go through the steps of the Clinical Judgment Measurement Model to make clinical decisions about patient care by recognizing and analyzing cues, prioritizing hypotheses, generating solutions, taking action, and evaluating outcomes.