Fundamentals of Respiratory Care Question and Answers

Fundamentals of Respiratory Care Under what conditions will the alveolar PACO2 rise above normal? - ANS if VA decreases relative to carbon dioxide production A 70-kg male patient has a VCO2 of 200 ml/min and a VA of 9 L/min. From this information, what can you infer? - ANS The patient will have a lower than normal PACO2. What is the primary determinant of the PAO2? - ANS PO2 in the inspired gas A normal person breathing 100% oxygen at sea level would have PAO2 of about what level? - ANS 670 mm Hg What is the highest PAO2 one could expect to observe in an individual breathing room air at sea level? - ANS 110 to 120 mm Hg When is the rate of gaseous diffusion across a biological membrane decreased? - ANS The partial pressure gradient is low. What is the primary factor that maintains the pressure gradient that drives oxygen from the capillaries into the interstitial spaces and into the cells? - ANS cellular consumption of oxygen What occurs in the bases of the upright lung? - ANS The V/Q is lower than the average. If the total hemoglobin content (Hb + HbO2) of a sample of blood is 20 g/dl and the oxyhemoglobin (HbO2) content is 15 g/dl, what is the HbO2 saturation? - ANS 75% At a PaO2 of 65 mm Hg, what is the approximate saturation of Hb with oxygen? - ANS 80% What is the approximate normal CaO2 - CO2 in a healthy adult at rest? - ANS 5 ml/dl According to the Fick principle, if oxygen consumption remains constant, an increase in cardiac output will manifest itself as which of the following? - ANS decrease in the CaO2 What role does the Bohr effect play in oxygen transport? - ANS enhances oxygen delivery to tissues and oxygen pickup at lungs A patient has a P50 value of 29 mm Hg. What does this indicate? - ANS decreased affinity of Hb for oxygen Which of the following statements is true regarding the Haldane effect? - ANS At high SaO2 levels, the capacity of blood to hold carbon dioxide decreases. Which of the following equations best describes oxygen delivery to the tissues? - ANS arterial oxygen content ´ cardiac output A patient with a normal PaO2 and cardiac output is exhibiting signs and symptoms of tissue hypoxia. What is the most likely cause? - ANS hemoglobin deficiency What is a uniform distribution of large molecules that attract and hold water? - ANS colloid Gas transport in the body is most affected by changes in which of the following variables? - ANS ambient pressure. A solution holding the maximum amount of solute in a given volume at a constant temperature is said to be what? - ANS saturated The most important physiological characteristic of solutions is their ability to exert pressure. - ANS true Which of the following is true regarding osmotic pressure? - ANS Osmotic pressure depends on the number of particles in solution. Which of the following is an isotonic solution? - ANS 0.90% NaCl