What medical condition results from decreased ventilation and increased carbon dioxide concentration in the blood?

Respiratory acidosis occurs when there is a decrease in ventilation, leading to an accumulation of carbon dioxide (CO2) in the blood. Under normal circumstances, the body maintains acid-base equilibrium by exhaling CO2, which is produced as a waste product of metabolism. When ventilation decreases—due to conditions like respiratory diseases, drug overdose, or neuromuscular disorders—the ability to exhale CO2 is impaired.

As CO2 levels rise, it reacts with water in the blood to form carbonic acid, which leads to a decrease in blood pH and results in acidosis. This condition often manifests with symptoms like confusion, lethargy, and shortness of breath, as the body struggles to maintain normal physiological functions.

The other choices pertain to different acid-base imbalances: metabolic acidosis is characterized by a decrease in blood pH due to metabolic processes, respiratory alkalosis is caused by excessive ventilation leading to decreased CO2 levels, and metabolic alkalosis results from an increase in blood pH due to factors like excessive vomiting or bicarbonate retention. Thus, the characteristic decrease in ventilation and resultant CO2 retention directly correlates with the definition of respiratory acidosis.