What is the normal pH of the blood?

Appeared in: SGPGI Nursing Officer-2024

Explanation

The normal pH of arterial blood is tightly regulated between 7.35 and 7.45.
This slightly alkaline environment is essential for optimal function of enzymes, transport of oxygen by hemoglobin, and overall cellular metabolism.
The body maintains this balance through complex mechanisms involving chemical buffers (like bicarbonate), the respiratory system (by regulating CO2), and the renal system (by excreting acids or retaining bicarbonate).

Option A: This option presents an inverted and illogical range. A pH of 7.10 represents severe acidosis, while 7.45 is the upper limit of normal.
Option C: This entire range is below 7.35, which defines a state of acidosis, not normal pH.
Option D: This range represents a state of moderate to severe acidosis, which is a serious medical condition requiring urgent intervention.

Clinical Relevance

Nursing practice connection: Knowing Normal Arterial Blood pH and Acid-Base Balance helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Nurses frequently monitor Arterial Blood Gas (ABG) results to assess a patient's acid-base status, particularly in critical care, emergency, and post-operative settings.
Deviations from the normal pH range are a critical indicator of underlying disease processes, such as respiratory failure (respiratory acidosis/alkalosis) or metabolic issues like diabetic ketoacidosis or kidney failure (metabolic acidosis).
What if? If a patient's ABG report showed a pH of 7.28, the nurse would recognize this as acidosis, immediately assess the patient's respiratory status and level of consciousness, notify the physician, and anticipate orders for interventions like administering sodium bicarbonate or adjusting mechanical ventilation settings.

How to Approach the Question

Identify the core of the question: it asks for a specific, fundamental physiological value—the normal pH of blood.
Recognize this as a factual recall question. These questions test your memory of key numbers and ranges essential for nursing practice.
Recall that the body's internal environment is tightly controlled (homeostasis) and the pH range is very narrow and slightly alkaline.
Mentally retrieve the specific range: 7.35 to 7.45.
Compare this recalled value to the given options and select the one that matches exactly.

Concept Tested & Keywords

QZCZvzB0yK1l1hF21UA5u0

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

E6 Nelson Textbook of Pediatrics(2024) — Volume 1 p. 554-556

Practise the full SGPGI Nursing Officer-2024

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