Egan’s Chapter 46 Practice Questions:

1. The goal of breathing and circulation is: tissue oxygenation

2. Dead space units: Alveoli that are ventilated but not perfused

3. Shunts units: Alveoli that are perfused but not ventilated

4. Normal resting oxygen consumption is approximately: 250 ml/min, Increases with activity, stress, and temp

5. Murray Lung Injury Scale quantifies the injury level using 4 factors: Chest X-ray findings, PaO2/FIO2 ratio, PEEP settings, Compliance

6. The most accurate and reliable measure of oxygenation efficiency is direct computation of: The physiologic shunt (Qs/Qt)

7. Alveolar-Arterial Oxygen tension difference: P(A – a)O2, Is a useful measure of the efficiency of gas exchange, If elevated indicates gas exchange problem

8. A healthy person breathing room air has a P(A – a)O2 of: 5 to 15 mm Hg, 100 – 150 if breathing 100%

9. PaO2/FiO2 Ration: The arterial PO2 to inspired oxygenatation has become important is the determination of the extent of acute lung injury (ALI) and Acute respiratory distress syndrome (ARDS). Most reliable index of gas exchange when FiO2 > .5 and PaO2 < 100.

10. A normal PaO2/FiO2 Ration while breathing room air is: About 400 to 500 mm Hg or greater than 380

11. ALI PaO2/FiO2 Ration <300 mm Hg, ARDS PaO2/FiO2 Ration <200 mm Hg

12.Oxygen consumption (Vo2): The volume of oxygen used by the body in milliliters per minute

13. Oxygen consumption may be useful in determining: Nutritional requirements, Adequacy of oxygen delivery, May occasionally help determine the cause of high ventilation requirements

14. V/Q mismatch: Alveoli that are receiving either partial ventilation or partial perfusion

15. Shunt calculation: Most accurate and reliable measure of oxygentation efficiency. Need arterial and mixed venous sample.

16. What is the single best indicator of effective ventilation?: PaCO2

17. Normal compliance of lung and chest wall: 60 – 100 ml/cm H2O

18. Normal resistance: 1 -2 cm H2O/sec, 5-10 for intubated patients

19. Peak airway pressure than 50-60 cm H2O is discouraged because: Increased risk of barotrauma and hypotension

20. Plateau pressure should not exceed: 30 cm H2O. It increases the risk of ventilator induced lung injury.

21. Unintended PEEP: Intrinsic PEEP; Alters trigger sensitivity, Leads to errors in compliance calculations, Overcome with applied PEEP, decrease tidal volume, Increase E time

22. Fora healthy person the average total work of breathing is: 0.3 to 0.5 J/L

23. The normal VC is: 70 ml/kg

24. A VC less than 10 to 15 ml/kg indicates: Considerable muscle weakness which may inhibit the ability to breathe spontaneously

25. Maximum Voluntary Ventilation (MVV): A measure used to assess respiratory muscle reserve, endurance, or fatigue

26. Normal MVV values for adults: 120 to 180 L/min

27. Normal O2 coast of breathing: 2-5 % of VO2, Amount of O2 consumes by ventilatory muscles

28. Central Venous-Right Atrial pressure (CVP): Is a measure of RA preload. The amount of venous return to the heart.

29. What is the normal CVP: 2 to 6 mm Hg, It is the lowest of all heart chambers

30. Placement of a swanganz catheter allows: Determination of CVP, PAP, and PCWP

31. Placement of catheter carries risk of: Pneumothorax, Hemothorax, Arrhythmias

32. Preload: The pressure that stretches the ventricular walls at the onset of ventricular contraction, Estimated with PCWP, LA pressure qhich reflects end diastolic pressure, Increased with LV failure

33. Normal arterial blood pressure: 120/80, Normal heart rate: 80 beats/min

34. Normal pulmonary arterial pressure (PAP): 25/10 mm Hg

35. Normal pulmonary capillary wedge pressure (PCWP): 5-10 mm Hg

36. Normal cardiac output (Qt): 5 L/min

37. Normal systemic vascual resistance (SVR): 900- 1400 dynes-sec/cm5

38. Normal pulmonary vascular resistance (PVR): 110-250 dynes-sec/cm5

39. Afterload: The load at which the ventricles must contract reflected as increased in SVR. The muscle tension requried by the left ventricle to generate blood flow.

40. Three primarily reason to measure Interacranial pressures (ICP): 1. to monitor patients at risk of life threatening intracranial hypertension, 2. to monitor for evidence of infection, 3. The assess the effect of therapy aimed at reducing ICP

41. Normal mean ICP of a supine patient: 10 to 15 mm Hg

42. The ICU came out of the: Polio epidemic of the 1950’s. Signals or values may be inaccurate due to?: Artifact, Factious events

43. Artifacts: Caused by motion, shift or spike, self resolving

44. Factitious events: real and out of range, temporary but may need attention