The normal range for pH of blood is?

Appeared in: JODHPUR AIIMS SNO-2018

Explanation

The normal pH of human arterial blood is maintained in a very narrow range of 7.35 to 7.45.
This range is optimal for metabolic functions, enzymatic reactions, and the proper transport of oxygen by hemoglobin.
The body's buffer systems, along with the respiratory and renal systems, work together to maintain this delicate balance, a state known as homeostasis.
Deviations from this range can lead to significant physiological problems and, if severe, can be life-threatening.

Option B: A pH range of 7.47-7.57 is higher than the normal range and indicates alkalosis, a state where the blood is too alkaline.
Option C: A pH range of 7.11-7.22 is significantly lower than the normal range and indicates a state of severe acidosis, where the blood is too acidic.
Option D: A pH range of 8.0-8.2 is extremely alkaline and is considered incompatible with life. The upper limit of pH at which a person can survive for more than a few hours is approximately 8.0.

Clinical Relevance

Nursing practice connection: Knowing Normal blood pH range and acid-base balance helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Nurses frequently monitor blood pH through Arterial Blood Gas (ABG) analysis, especially in critically ill patients, to assess their metabolic and respiratory status.
Understanding ABG results is crucial for identifying life-threatening conditions like acidosis or alkalosis and for evaluating the effectiveness of treatments.
What if? A patient with chronic obstructive pulmonary disease (COPD) has a pH of 7.32. This indicates respiratory acidosis due to CO2 retention. The nursing priority would be to improve ventilation, possibly through positioning, oxygen therapy as prescribed, and monitoring for further respiratory distress.

How to Approach the Question

This is a factual recall question that tests your knowledge of a fundamental physiological value.
First, identify the keywords in the question: 'normal range' and 'pH of blood'.
Recall the specific, narrow range for normal arterial blood pH from your studies.
Compare the recalled value (7.35-7.45) with the given options.
Select the option that exactly matches the correct physiological range.
Eliminate other options by recognizing them as representing acidosis (too low) or alkalosis (too high).

Concept Tested & Keywords

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E6 Nursing Fundamentals Potter Perry 12e Part 5 p. 54-56

E6 Physiology Guyton 4SAE Part 2B p. 66-68

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