Pulse oximeters use wavelengths of two lights (infrared light at 940 nm and red light at 660 nm), which are absorbed differently by either oxyhemoglobin or the reduced hemoglobin to measure arterial oxygen-saturation level (SpO₂).

The design of the NIBP parameter of a patient monitor is required to be proven to be safe and effective for use in the diagnosis, and treatment of disease states and underlying chronic conditions, and in the prescribing of medications and other therapies. This testing is governed by national and international standards including AAMI/ANSI SP10 and IEC 80601-1-2-30 for minimum performance and safety. The performance of NIBP monitors are required to be evaluated or tested during scheduled maintenance by the manufacturer.

Blood pressure can be measured using a variety of techniques, which can be classified into two major categories: invasive and non-invasive. The invasive approach inserts a catheter into an artery of a test subject. The catheter may contain a pressure transducer at its tip or it may be fluid-filled and couple the blood pressure through the fluid to an external transducer. The change of fluid pressure (blood pressure) in the subject's artery is measured invasively.

Doctors have determined a normal range for both systolic and diastolic blood pressure after examining the blood pressure of many people. The following figures can be used as a guide for adult blood pressure:
1. Normal blood pressure: less than 120/80 mmHg
2. High/Normal: between 120/80 and 140/90 mmHg
3. High: equal to or more than 140/90 mmHg
4. Very high: equal to or more than 180/110

70 % of the original capacity with operation at 25 °C room temperature.