Copyright Goodheart-Willcox Co., Inc. Chapter 18 Vital Signs, Height, and Weight 473 Using a Pulse Oximeter Another way to measure how well oxygen is being used in the body is to determine oxygen saturation in the blood. A pulse oximeter is used to measure blood oxygenation. It is commonly used when vital signs are being measured and is also used to measure oxygen effectiveness for a resident receiving oxygen. A pulse oximeter is applied to the finger (or sometimes the earlobe or toe). It uses infrared light that passes through the body tissue of the finger. A pulse oximeter’s digital display will show the amount of oxygen in the blood as a percentage (Figure 18.23). A normal reading is 95 percent to 100 percent oxygen in the blood. A reading below 85 percent is too low and is called hypoxia (lack of adequate oxygen in the body). The notation used for recording oxygen saturation in the blood is SpO2. Using a pulse oximeter has minimal risks. If improperly placed, the pulse oximeter may give an inaccurate reading. If a pulse oximeter is used continuously, pay attention to the skin around and under the device and check for possible irritation. Respirations (rate, regularity, and depth) and pulse oximeter percentages are recorded on a form provided by the healthcare facility or in the electronic record. Any irregularities must be reported to the licensed nursing staff. How Is Blood Pressure Measured? Blood pressure is the force of blood pushing against the body’s arterial walls. Measuring blood pressure is important. If a resident has hypotension (blood pres- sure that is too low), the body may not be getting enough oxygen and nutrients. Conversely, hypertension (blood pressure that is too high) may place too much pressure on the walls of the arteries (Figure 18.24). This pressure can cause a stroke or other cardiovascular problems. High or low blood pressure can also signal or cause certain diseases and conditions, such as heart disease, kidney damage or failure, various injuries, or dizziness. Measuring Blood Pressure A blood pressure reading is made up of two pressure levels, which are measured as the heart beats. The first is systolic blood pressure, which is pressure when the heart muscle contracts and pushes blood through the artery. The second is diastolic blood pressure, which is pressure when the heart muscle relaxes. These pressure levels are measured using a stethoscope and a sphygmomanometer. Both pressure levels are measured in millimeters of mercury (mmHg). Systolic blood pressure is the higher number and the first beat heard (as a tapping sound) and measured (as 120 mmHg, for example). Diastolic blood pressure is the lower number and is the last beat heard and measured (as 80 mmHg, for example). For someone with these measurements, blood pressure would be recorded as the frac- tion 120/80 mmHg. The average ranges of normal blood pressure for adults, chil- dren, and infants can be found in Figure 18.25. Think About This The Centers for Disease Control and Prevention recently reported that 75 million American adults (29 percent) have high blood pressure. This means that about one in every three adults has hypertension. Approximately one-half (54 percent) of those with high blood pressure have their condition under control. Click and Photo/Shutterstock.com Figure 18.23 The pulse oximeter is placed on the finger and measures oxygen saturation in the blood. Blood Pressure Classification Hypotension Normal Elevated Hypertension 90/60 mmHg 90–120/60–80 mmHg 120–129/80 mmHG Stage 1: 130–139/80–90 mmHG Stage 2: 140/90 mmHg Figure 18.24 Blood pressure measurements are important indicators of health and may indicate or cause certain diseases or conditions.