A 21-Year-Old Man Is Brought to the Emergency Department After

question 4

Multiple Choice

A 21-year-old man is brought to the emergency department after being found unresponsive in a public restroom.  He has a history of injection drug use.  Temperature is 36.1 C (97 F) , blood pressure is 110/70 mm Hg, pulse is 62/min, and respiratory rate is 8/min.  On physical examination, the patient is unconscious with pinpoint pupils.  Endotracheal intubation is performed, and mechanical ventilation is begun.  The ventilator settings are adjusted to provide a minute ventilation of 6.0 L/min.  Calculated alveolar ventilation is 4.2 L/min.  Which of the following most likely accounts for the difference between these 2 parameters?

• A)Dead space volume
• B)Functional residual capacity
• C)Residual volume
• D)Respiratory rate
• E)Tidal volume