Respiratory Case Study


A 60-year-old woman is in the intensive care unit for treatment of respiratory failure.  Her underlying disease is emphysema, caused by years of smoking. Her trachea is intubated and she is on a mechanical ventilator to assist breathing.  The following lab results are obtained:

From arterial blood:

pH = 7.5

PCO2 = 35mm Hg

PO2 = 63mm Hg

Hemoglobin = 9g/dl

oxygen saturation = 73%

From Cardiac catheter in pulomonary artery:

Cardiac output = 5 L/min

PCO2 = 45mmHg

PO2 = 38mm Hg



In order to thoroughly respond to these questions be sure to review external and internal gas exchange.


1.)  Describe pulmonary and systemic circulation with specific reference made to both external and internal respiratory exchange.


2.) How are oxygen and carbon dioxide transported in the blood? Elaborate on the role of hemoglobin in oxygen transport.


3.)  What is normal arterial P02 and why is the patient's different? Explain.

4.) Describe the gross effects of emphysema on lung tissues. How did smoking contribute to this problem?

5.) What is meant by oxygen saturation? How much oxygen is delivered to the systemic tissues returns to the right atrium of the heart in a healthy individual? this patient?

6.) The patient is currently on a mechanical ventilator, what further treatments may be necessary for this patient?