Respiratory Therapy - Mechanical Ventilation

  1. Define compliance using a mathematical equation.
  2. Define VD/VT using a mathametical equation.
    (PaCO2 - PECO2)/PaCO2
  3. Define minute ventilation using a mathmatical equation.
    VE = VT X RR
  4. Define alveolar ventilation using a mathematical equation.
    (VT - VD) X RR
  5. State the 13 physiological effects of positive pressure ventilation.
    • Increases Mean Airway Pressure
    • Increases Mean Intrathoracic Pressure
    • Decreases Venous Return
    • Decreases Cardiac Output
    • Increases Intracranial Pressure
    • Decreases Urinary Output
    • Decreases Work of Breathing
    • Mechanical Bronchodilation
    • Increases Deadspace Ventilation
    • Increases Intrapulmonary Shunting
    • Manipulation of Level of Ventilation
    • Effects on GI (Increases Gastric Secretions)
    • Psychological Effect (Insomnia, Anxiety, Frustration, Depression, Apprehension, Fear)
  6. Your 120 pound (IBW) patient has a tidal volume of 500 ml and a delivery rate of 12 bpm. Calculate the patient's minute ventilation.
    12 X 500 = 6.000
  7. Your 120 pound (IBW) patient has a tidal volume of 500 ml and a delivery rate of 12 bpm. Calculate the patient's alveolar ventilation.
    (500 - 120) 12 = 4.56 L/m
  8. Give the normal value for pulmonary shunt.
    2 - 5%
  9. Give the normal value of BUN.
  10. Give the normal value of creatinine.
    0.7 - 1.5
  11. What are the 4 variables that a ventilator uses to end inspiration?
    • Time
    • Pressure
    • Flow
    • Volume
  12. Define mean airway pressure.
    The average amount of air in the airway during respiratory cycle.
  13. If you have the following parameters calculate the total minute ventilation.
    VT = 700
    Mode = SIMV
    Rate = 10
    Rate Spt = 4
    VT Spt = 400
    10 X 700 + 4 X 400 = 8.6 L
  14. When CPAP is in use, the total amount of the work of breathing is produced by the _________.
  15. Interpret the following blood gas:
    pH = 7.48
    PaCO2 = 30 mmHg
    PaO2 = 79
    HCO3 = 26
    Uncompensated respiratory alkalosis w/ mild hypoxemia
  16. Mechanical ventilation is used to support ____a____ and one of its most frequent uses is an acute care setting is to manage conditions associated with ____b____.
    • a) hypoventilation
    • b) post anesthesia recovery
  17. Poiseuille's Law demonstrates that the work of breathing increases 16 times when the radius of an airway is reduced by _________ of its original size.
  18. During mechanical ventilation rounds, you are trending a patient's dynamic compliance measurements. The primary purpose of this procedure is to monitor changes in the patient's:
    airway pressure
  19. Dr. Abel asks you to recommend a method for assessing the elastic properties of a patient's lungs. You would suggest measuring the:
    static compliance
  20. The criticalrange of dynamic compliance is between ____a____ and this measurement is used to evaluate the condition of a patient's ____b____.
    • A) 30 and 40 mL/cm H2O
    • B) airways
  21. The pulmonary measurements for an intubated post-operative patient are below:
    Corrected Tidal Volume = 900 mL
    PEEP = 5 cm H2O
    Peak Airway Pressure = 60 cm H2O
    Plateau Pressure = 36 cm H2O
    Based on this information, the dynamic compliance is about:
    16 mL/cm H2O
  22. The critical range of static compliance is between ____a____ and this measurement is used to evaluate that condition of a patient's ____b____.
    • A) 40 and 60 mL/cm H2O
    • B) lung parenchyma
  23. The pulmonary measurements for a patient being treated for a 40% tension pneumothorax are below:
    Corrected Tidal Volume = 750 mL
    PEEP = 8 cm H2O
    Peak Airway Pressure = 74 cm H2O
    Plateau Pressure = 49 cm H2O
    Based on this information, the static compliance is about:
    18 mL/cm H2O
  24. The volume of air in the conducting airways is known as ____a____ deadspace and under normal conditions it can be estimated to be about ____b____ ml per pound of ideal body weight.
    • A) Anatomic
    • B) One
  25. Dr. Plauche asks you to evaluate his patient in the CCU who has developed oxygenation failure secondary to congestive heart failure. In assessing the patient, you would expect to observe all of the following clinical signs except:
  26. During spontaneous breathing, alveolar pressure is _________ barometric pressure at end-inspiration.
    equal to
  27. During positive pressure ventilation, the pressure in the airway, alveoli, and pleural space:
  28. You are assessing the condition of a 20 year-old patient with status asthmaticus who is being mechanically ventilated. You note that the peak inspiratory pressures as well as the patient's work of breathing have steadily increased over the last three hours. You would initially check the patient's:
    breath sounds
  29. Ms. Warren has the following laboratory results: prothrombin time: 5 sec., bilirubin level: 60 mg/L, albumin level: 13 g/L. This finding suggests _________ impairment.
  30. In reviewing Mr. Johnason's chart, you note that he is receiving total parenteral nutrition (TPN). This means that he is getting a complete nutritional program provided by any route other than:
  31. Patients with neurological impairment due to ventilatory and oxygenation failure will usually describe their headache as _________ in the head.
  32. The ventilator is a _________ controller if the pressure waveform does not change when airflow resistance and compliance are changed.
  33. Th eventilator is a volume controller if the _________ is measured and used as a feedback signal to control the volume delivered.
  34. Heated wire grids, venture pneumotachometers and vortex sensors are devices used to measure the inspiratory:
  35. When the ventilator delivers a breath every 5 seconds, it is operating under the ____a____ mode and the breaths are considered ____b____.
    • A) control
    • B) time-triggered
  36. In order to control the I:E ratio during mechanical ventilation, a _________ cycled mechanism is most effective.
  37. The term "triggered" describes the mechanism by which ventilator:
    begins the inspiratory phase
  38. You are asked to calculate the VD/VT for Mr. Goosby, a 19-year-old patient who is being mechanically ventilated following a motor vehicle crash. The following information is available from teh chart:
    PaO2 = 64 mmHg
    PaCO2 = 60 mmHg
    PECO2 = 18 mmHg
    VE = 16 L
    FIO2 = 40%
    His deadspace percentage is:
  39. A VD/VT ratio of a 19-year-old patient who is being mechanically ventilated following a motor vehicle crash, is 70%. Th edifferential diagnosis may include:
    pulmonary embolism
  40. The pressure gradient that must be generated between the airway opening and alveoli in order to produce inspiratory flow is known as:
    transairway pressure
  41. PEEP offers which of the following physiological benefits?
    • Increased functional residual capacity
    • Decreased alveolar distending pressures
    • Decreased work of breathing
  42. Patients with ____a____ are least likely affected by the hemodynamic effects of PEEP because the compliance of the patients is very ____b____.
    • A) ARDS
    • B) low
  43. Mrs. Smith is being ventilated with assist control mode at a rate of 10 breaths per minute. Under this setting, a ventilator triggered breath will be delivered every _________ seconds if the patient becomes apneic.
  44. Mechanical ventilation is initiated with pressure support of 15 cm H2O. Which of the following parameters would you monitor in order to ascertain that the pressure support level is adequate?
    • Spontaneous Tidal Volume
    • Spontaneous Respiratory Rate
    • Arterial Blood Gas Results
  45. Dr. Goodnow asks you to initiate mechanical ventilation on a patient with myasthenia gravis. In order to obtain an I:E ration that is near physiologic, you would adjust the ventilaatior setting until an I:E ratio is about _________ is reached.
  46. How do you assess adequacy of ventilation
  47. Decreas in VA =
    • Increase in PaCO2
    • Hypoventilation
  48. Increase in VA =
    • Decrease in PaCO2
    • Hyperventilation
  49. What factors affect VA?
    • Underestimation of tidal volume
    • Improper setting of ventilator controls
    • Leaks in the circuit
    • Tubing and ventilator compliance
    • Measuring tidal volume
  50. What are the clinical signs of O2 failure and hypoxia?
    • Hypoxemia
    • Dyspnea
    • Tachypnea
    • Tachycardia
    • Cyanosis
  51. When is static compliance measured?
    When no air flow is present.
  52. State the static compliance equation.
    (Corrected Tidal Volume)/(Plateau Pressure - PEEP)
  53. What is the critical range for static compliance?
    40 - 60 mL/cm H2O
  54. When is dynamic compliance measured?
    When air flow is present.
  55. State the dynamic compliance equation.
    (Corrected Tidal Volume)/(PIP - PEEP)
  56. What is the critical range for dynamic compliance?
    30 - 40 mL/cm H2O
  57. State the equation for corrected tidal volume.
    Exp VT - (PIP - PEEP)3
  58. What could be the cause of both peak and plateau pressures sincreasing?
    • Pulmonary edema
    • Tension pneumothorax
    • Splinting-thoracic injury
    • Bronchial intubation
    • Atelectais-pneumonia
  59. Why could peak pressure be increased?
    • Increased peak flow
    • Small or obstructed ET tube
    • Mucus plug
    • Bronchospasm
    • Bronchiolitis
  60. What clincal conditions decrease static compliance?
    • Atelectasis
    • ARDS
    • Tension Pneumothorax
    • Obesity
    • Retained secretions
  61. What clinical conoditions decrease dynamic compliance?
    • Bronchospasm
    • Kinking of the ET tube
    • Airway obstruction
  62. What 5 mechanisms lead to ventilatory failure?
    • Hypoventilation
    • Persistent V/Q mismatch
    • Persistent intrapulmonary shunting
    • Persistent diffusion defect
    • Persistent reduction of PiO2
  63. How can oxygenation failure be diagnosed?
    • Severe hypoxemia
    • Patient does not respond to moderate to high levels of supplemental oxygen
    • Hypoxia can occur with a normal PaO2
  64. What is MAWP directly related to?
    • Inspiratory time
    • RR
    • PIP
    • PEEP
    • VT
  65. What is the amount of pressure transmitted to intrathoracic space dependent on?
    • Lung compliance
    • Thoracic compliance
  66. If you have a decreased lung compliance (stiff lung) is the amount of pressure transmitted increased or decreased?
  67. If you have a decrease in compliance of the thorax (stiff thorax) is the amount of pressure transmitted greater or lower?
  68. Why is venous return decreased due to positive pressure ventilation?
    • Increase in intrathoracic pressure
    • Compression of the vessels
    • Decrease in venous flow to the right side of the heart
  69. Why is cardiac output decreased due to positive pressure ventilation?
    • Venous return is decreased
    • A reduction in stroke volume occurs
    • A reduction of cardiac output and pulmonary blood flow occurs
  70. Why is intracranial pressure increased due to positive pressure ventilation?
    • Venous return is decreased
    • Blood will pool in periphery and cranium
    • An increase of volume in cranium will occur
  71. Why is urinary output decreased due to positive pressure ventilation?
    • Cardiac output decreases
    • Blood flow decreases
    • Filtration rate is altered
    • Urine formation is diminished
  72. Why is work of breathing decreased due to positive pressure ventilation?
    Force for ventilation is provided by the ventilator
  73. How is mechanical bronchodilation produced due to positive pressure ventilation?
    Positive pressure causes mechanical dilation of all conducting airways
  74. Why is deadspace ventilation increased due to positive pressure ventilation?
    • Positive pressure distends conducting airways
    • It inhibits venous return
    • Portion of the VT that is deadspace increases
    • Alteration in distribution of ventilation occurs
  75. What is the normal VD/VT ratio?
    0.20 to 0.40
  76. What will mechanical ventilation cause VD/VT ratios to increase to?
    0.40 to 0.60 in the normal individual
  77. Why is intrapulmonary shunt increased due to positive pressure ventilation?
    • With positive pressure ventilation, gas distribution and pulmonary perfusion is altered
    • Ventilation to gravity depended area decreases
    • Perfusion to these areas increases
  78. Mecanical ventilation may increase shunt fraction to approximately what percent in a normal adult?
  79. Manipulating the level of ventilation can cause:
    • Hyperventilation or hypoventilation by innappropriate settings
    • RR, VT, IT, and flow can be manipulated
  80. Why is GI effected due to positive pressure ventilation?
    Stress from positive pressure ventilation leads to and increase in gastric secretion and results in stress ulcers.
  81. What is indicated with an increase in BUN?
    Renal Failure
  82. An increase in creatinine indicated what?
    Renal Failure
  83. What does TPN stand for?
    Total Parenteral Nutrition
  84. What is oliguria?
    Decreased Urine Output
  85. What values define urine output?
    • U.O. of < 400 mL in 24 hours
    • U.O. < 160 mL in 8 hours
  86. What is ventilatory work dependent on?
    • Load - Pressure required to deliver VT
    • Elastic Load - Volume/Compliance
    • Resistance Load - RAW and Iflow
  87. What classifies a mechanical ventilator?
    • Input Power
    • Drive Mechanism
    • Control Circuit
    • Control Variables
    • Phase Variables
    • Output Waveforms
    • Alar Systems
  88. What are the types of input power?
    • Pneumatic - 50 psi compressed gas
    • Electric - Uses electricity
    • Combined - Uses both pneumatic and electric
  89. What do drive mechanisms provide?
    Mechanical force that produces the flow of gas necessary for delivery of VT
  90. The type of drive mechanism determines chaaracteristic flow and pressure patterns. The types of drive mechanisms are:
    • Piston
    • Bellows
    • Reducing Valve
    • Microprocessor
  91. What does a control circuit do?
    It controls venilator drive mechanism or output control valve.
  92. What kind of control circuits are there?
    • Mechanical
    • Pneumatic
    • Fluidic
    • Electric
    • Electronic
  93. What does the trigger variable do?
    It determines the start of inspirations
  94. What does the limit do?
    The limit does not allow variable to rise above a preset value.
  95. What is the cycle?
    The method the ventilator uses to end inspiration.
  96. What is the baseline?
    The variable that is controlled during the expiratory phase/expiratory time
  97. WHat are the types of alarm systems?
    • Input Power Alarms
    • Control Circuit Alarms
    • Output Alarms
  98. List the modes of mechanical ventilation?
    • Spontaneous
    • PEEP
    • CPAP
    • BiPAP
    • CMV
    • A/C
    • IMV
    • SIMV
    • MMV
    • PSV
    • PCV
    • APRV
    • IRV
  99. What does the ventilator provide to the patient in spontaneous mode?
    • Flow to patient in a timley manner
    • Flow adequate to meet patient's inspiratory needs
    • Provides adjunct modes like PEEP
  100. What is PEEP?
    Increased baseline pressure above zero.
  101. What are the indications for PEEP?
    • Intrapulmonary shunting and refractory hypoxemia
    • Decreased FRC and lung compliance
  102. Complications of PEEP
    • Decreased venous return
    • Barotrauma
    • Increased ICP
    • Alterations of renal functions and H2O metabolism
  103. When should CPAP be used?
    • On a spontaneously breathing patient
    • Intrapulmonary shunting and refractory hypoxemia
    • Decreased FRC and lung compliance
    • On a patient with adequate lung function
  104. How is CPAP applied to patients?
    • Adult - mask, ET, nasal mask
    • Neonate - nasal method
  105. List the indications for BiPAP?
    • Prevent intubation of end-stage COPD patients
    • Support patients in chronic ventilatory failure
    • Restrictive chest wall disease, neuromuscular disease and nocturnal hypoventilation
  106. Where should BiPAP settings be set to start with?
    • IPAP - 8 cm H2O
    • EPAP - 4 cm H2O
    • These are increased by 2 cm H2O increments at a time
  107. BiPAP's volume delivered is ovtained by:
    • Increase IPAP level
    • Decrease EPAP level
    • Increase compliance
    • Decrease air flow resistance
  108. How does a CMV work?
    • It delivers a preset tidal volume and respiratory rate
    • The machine is responsible for initiation and delivery of each tidal volume
    • Total minute ventilation determined by machine
  109. List the indications for CMV.
    • Patient fights ventilator
    • Seizure activity or tetnus
    • Complete rest for patient
    • Crushed chest injury
  110. What are the hazards of CMV?
    • Apnea
    • Hypoxia
    • - These are caused by disconnect or the ventilator failling to operate.
  111. What does assist control do?
    • Sets a rate and tidal volume
    • Patient can initiate inspiratory phase
    • Minute ventilation may increase from preset
  112. What is the indication for assist control
    Full ventilatory failure
  113. What does IMV do?
    • Delivers a control breath
    • Allows patient to breath spontaneously at any tidal volume
    • Allows for breath stacking
  114. What does SIMV do?
    • Ventilator delivers a control breath
    • Patient breathes spontaneously at any tidal volume
    • Mandatory breaths are synchronized with patients spontaneous breath
    • Avoids breath stacking
  115. What does MMV do?
    • A minimum minute volume is set
    • Patient receives volume by breathing totally spontaneously, being mechanically ventilated, combination of spontaneous and mechanical ventilation.
  116. What does PSV do?
    • Lowers work of spontaneous breathing and augments patient's spontaneous tidal volume
    • Patient establishes frequency, inspiratory flow, and inspiratory time
  117. What does PCV do?
    • It makes all breathes time or patient triggered, pressuer limited and time cycled
    • Minimizes PIP while maintaining adequate oxygenation and ventilation
  118. What does APRV do?
    It provides 2 levels of CPAP and allows spontaneous breathing at both levels.
  119. What does IRV do?
    • Lengthens inspiratory time and shortens expiratory time
    • 2:1 to 4:1
    • It is used with PCV
Card Set
Respiratory Therapy - Mechanical Ventilation
Exam 1 Flashcards