Sp O₂ is measured by -

Appeared in: RUHS, Jaipur, PB B.Sc Nursing Entrance-2023

Explanation

A pulse oximeter is the standard noninvasive device used to measure peripheral oxygen saturation (SpO2).
It works by passing light through a translucent part of the body (like a fingertip) and measuring the differential absorption of light by oxygenated and deoxygenated hemoglobin.
This provides an estimate of the percentage of hemoglobin in the arterial blood that is saturated with oxygen.
Normal SpO2 values are generally considered to be between 95% and 100%.
A value below 90% is typically considered a clinical emergency requiring intervention.

Option A: A sphygmomanometer is used to measure arterial blood pressure, which is the force of blood against the artery walls. It does not measure blood oxygen levels.
Option C: An ECG (Electrocardiogram) records the electrical signals of the heart. It is used to detect cardiac abnormalities like arrhythmias, ischemia, or infarction, not oxygen saturation.
Option D: An otoscope is a diagnostic tool used for the visual examination of the ear canal and the tympanic membrane (eardrum).

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Measurement of SpO2 (Peripheral Oxygen Saturation) as background academic context rather than a clinical decision trigger.
Monitoring SpO2 is a critical nursing responsibility for assessing a patient's respiratory status and response to treatment, especially in postoperative, respiratory, or critically ill patients.
A sudden drop in SpO2 is an early warning sign of respiratory compromise and requires immediate nursing assessment and intervention.
Patient safety can be compromised if factors affecting accuracy (e.g., poor perfusion, nail polish, patient movement) are not considered, leading to false readings and inappropriate clinical decisions.

How to Approach the Question

First, identify the key term in the question, which is 'SpO2'.
Recall the definition of SpO2: it stands for peripheral oxygen saturation, a measure of the oxygen level in the blood.
Systematically review each option and recall its primary function.
Option A, Sphygmomanometer, measures blood pressure.
Option B, Pulse oximeter, is known for measuring oxygen saturation.
Option C, ECG, measures the heart's electrical activity.

Concept Tested & Keywords

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E6 Nursing Fundamentals Potter Perry 12e Part 3 pp. 23-25, 24-26

E6 Nelson Textbook of Pediatrics(2024) — Volume 1 p. 661-663

Practise the full RUHS, Jaipur, PB B.Sc Nursing Entrance-2023

Attempt every question from this paper in a timed mock, then review the full solution for each one.