Low Carbon Dioxide Levels in Blood

The functioning of all body systems and organs depends on maintaining the acid-base balance in body fluids. A low level of carbon dioxide in blood, called hypocapnia, is a red flag signaling that something is upsetting the balance.

Normality

Regardless of altitude, the normal concentration of CO2 in blood is equivalent to an atmospheric partial pressure at sea level of 35 to 45 mmHg, according to the book “Medical-Surgical Nursing.”

Imbalance

A partial pressure of CO2 (PaCO2) lower than 35 mmHg indicates that the blood is no longer sufficiently acidic, observes the book “Medical-Surgical Nursing.”

Significance

Metabolic reactions depend on the acid-base balance, observe Professor Arthur Vander and his co-writers in the book “Human Physiology.” Too little or too much acid in body fluids indicates some underlying condition that, if it persists, will do widespread harm, interfering with nerve impulses and muscle contraction.

Possible Causes

Low PaCO2 can arise from loss of acidic fluids, such as through vomiting; excessive retention of sodium bicarbonate; or hyperventilation, according to the book “Understanding Pathophysiology.”

Symptoms

Symptoms may include weakness; muscle cramps; shallow, slow respirations; confusion; convulsions; abnormally rapid beating of the upper heart chambers (atrial tachycardia); dizziness; tingling of the extremities; or coma, observe the authors Sue Huether, Ph.D. and Kathryn McCance, Ph.D.

References

• “Medical-Surgical Nursing, 6th edition”; Joyce M. Black, Jane Hokanson Hawks, and Annabelle M. Keene; 2001
• “Human Physiology: the Mechanisms of Body Function, 8th edition”; Arthur Vander, James Sherman, and Dorothy Luciano; 2001
• “Understanding Pathophysiology, 2nd edition”; Sue E. Huether and Kathryn L. McCance; 2000

Resources

• U.S. National Library of Medicine and NIH: Alkalosis