Egans chapter 46

  1. The goal of breathing and circulation is..
    tissue oxygenation
  2. Dead space units
    Alveoil 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 defference
    P(A - a)O2
    • Is a useful mesure of the efficiency of gas exchange
    • If elvated 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 oxygentation 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 breating room air is...
    About 400 to 500 mm Hg or greater than 380

    • ALI PaO2/FiO2 Ration <300 mm Hg
    • ARDS PaO2/FiO2 Ration <200 mm Hg
  11. Oxygen consumption
    The volume of oxygen used by the body in milliliters per minute
  12. Oxygen consumption may be useful in determining:
    • Nutritional requriments
    • Adequacy of oxygen delivery
    • May occasionally help determine the cause of high ventilation requriments
  13. V/Q mismatch
    Alveoli that are receiving either partial ventilation or partial perfusion
  14. Shunt calculation
    • Most accurate and reliable measure of oxygentation efficiency
    • Need arterial and mixed venous sample
  15. What is the single best indicator of effective ventilation?
  16. Normal compliance of lung and chest wall!
    60 - 100 ml/cm H2O
  17. Normal resistance!
    • 1 -2 cm H2O/sec
    • 5-10 for intubated patients
  18. Peak airway pressure than 50-60 cm H2O is discouraged because...
    Increasked risk of barotrauma and hypotension
  19. Plateau pressure should not exceed...
    • 30 cm H2O
    • It increases the risk of ventilator induced lung injury
  20. Unintended PEEP
    • Intrinsic PEEP
    • Alters trigger sensitivity
    • Leads to errors in compliance calculations
    • Overcome with applied PEEP, decrease tidal volume, Increase E time
  21. For healthy person the average total work of breathing is...
    0.3 to 0.5 J/L
  22. The normal VC is...
    70 ml/kg
  23. A VC less than 10 to 15 ml/kg indicates...
    Considerable muscle weakness which may inhibit the ability to breathe spontaneously
  24. Maximun Voluntary Ventilation
    A measure used to assess respiratory muscle reserve, endurance, or fatigue
  25. Normal MVV values for adults!
    120 to 180 L/min
  26. Normal O2 coast of breathing!
    • 2-5 % of VO2
    • Amount of O2 consumes by ventilatory muscles
  27. Central Venous-Right Atrial pressure
    • Is a measure of RA preload
    • The amount of venous return to the heart
  28. What is the normal CVP!
    • 2 to 6 mm Hg
    • It is the lowest of all heart chambers
  29. Placement of a swan-ganz catheter allows...
    Determation of CVP, PAP, and PCWP
  30. Placement of catheter carries risk of...
    • Pneumothorax
    • Hemothorax
    • Arrhythmias
  31. 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
  32. Normal arterial blood pressure!
  33. Normal heart rate!
    80 beats/min
  34. Normal pulmonary arterial pressure!
    25/10 mm Hg
  35. Normal pulmonary capillary wedge pressure!
    5-10 mm Hg
  36. Normal cardiac output!
    5 L/min
  37. Normal systemic vascual resistance!
    900- 1400 dynes-sec/cm5
  38. Normal pulmonary vascular resistance!
    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:
    • to monitor patients at risk of life threatening intracranial hypertension
    • to monitor for evidence of infection
    • Th 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
  43. Signals or values may be inaccurate due to?
    • Artifact
    • Factious events
  44. Artifacts
    • Caused by motion
    • shift or spike
    • self resolving
  45. Factitious events
    • real and out of range
    • temporary but may need attention
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    • Normal sinus Rhythm
    • The PR interval is consistant
    • The QRS complex is no longer than 0.12
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    • Sinus arrhythmia
    • Recognized by irregular spacing between the QRS complex
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    • First degree heart block
    • PR interval is longer than .20 sec
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    Atrial flutter
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    • Premature ventricular contractions
    • The QRS is wider than normal
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    Ventricular tachycardia
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    • Ventricular Fibrillation
    • The most life threatening arrhythmia
    • Requries rapid defilbration and CPR
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Egans chapter 46
Chapter 46