Overview ↑ O2 demand → ↑ respiratory rate and ↑ tidal volume → ↑ minute ventilation ↑ O2 consumption and ↑ CO2 production Arterial blood no change in PaO2 and PaCO2 ↑ minute ventilation and ↑ efficiency of gas exchange ensure that there is neither a decrease in PaO2 nor an increase in PaCO2 ↓ pH during strenuous exercise secondary to lactic acidosis Venous blood ↑ PvCO2 skeletal muscle adds more CO2 than usual to venous blood no change in PaCO2 sufficient ↑ minute ventilation to remove excess CO2 Pulmonary blood flow ↑ cardiac output → ↑ pulmonary blood flow → ↓ pulmonary resistance pulmonary blood flow becomes more evenly distributed throughout lungs V/Q ratio from lung apex to lung base becomes more uniform ↓ physiologic dead space Oxygen-hemoglobin dissociation curve ↑ tissue PCO2, ↓ tissue pH, and ↑ temperature → shifts to right ↓ hemoglobin affinity for O2 → ↑ O2 unloading in exercising skeletal muscle Chronic changes include ↑ cardiac chamber size and ↑ wall thickness due to hypertrophy ↑ ejection fraction and ↑ cardiac output due to greater efficiency ↑ maximum oxygen consumption (VO2 max) during exertion
QUESTIONS 1 of 3 1 2 3 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (M1.PL.15.23) A person is exercising strenuously on a treadmill for 1 hour. An arterial blood gas measurement is then taken. Which of the following are the most likely values? Tested Concept QID: 100826 Type & Select Correct Answer 1 pH 7.38, PaO2 100, PCO2 69 HCO3 42 10% (6/61) 2 pH 7.36, PaO2 100, PCO2 40, HCO3 23 77% (47/61) 3 pH 7.32, PaO2 42, PCO2 50, HCO3 27 5% (3/61) 4 pH 7.56, PaO2 100, PCO2 44, HCO3 38 0% (0/61) 5 pH 7.57 PaO2 100, PCO2 23, HCO3 21 7% (4/61) M 1 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 Review tested concept Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK