What are common signs of inadequate ventilation?

Inadequate ventilation leads to a failure in the effective exchange of gases, which can manifest in several specific and observable signs. Abnormal respiratory rates indicate that the body is struggling to maintain adequate ventilation, whether it's too fast (tachypnea) or too slow (bradypnea). Cyanosis, which is the bluish discoloration of the skin, particularly around the lips or extremities, signifies that tissues are not receiving enough oxygen, pointing directly to hypoxemia caused by inadequate ventilation. Diminished breath sounds may indicate that air is not moving effectively in and out of the lungs, suggesting an obstruction or reduced airflow in the respiratory passages.

In contrast, the other options either describe signs that would not typically indicate inadequate ventilation or include symptoms that could result from various other conditions unrelated to ventilation status. For instance, increased heart rate and elevated blood pressure can be responses to stress or hypoxia in general but are not specific indicators of inadequate ventilation. High oxygen saturation and alertness usually indicate effective ventilation and oxygen delivery rather than poor ventilation. Weight loss and fatigue may be associated with chronic conditions affecting the respiratory system but are not immediate indicators of acute inadequate ventilation.