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  1. Calculate the amount of pressure needed to attain a tidal volume of 0.5L (500ml) for a patient with normal respiratory system compliance 0.1 L/cm H2O.
    • C = ΔV/ΔP so ΔP = ΔV/C, so
    • P = 0.5 L/0.1 L/cm H2O or 5 ml/cm H2O
  2. What is normal compliance in a spontaneously breathing patient?
    0.05 to 0.17 L/cm H20 or 50 to 170 ml/cm H20
  3. What is normal compliance is an intubated male patient?
    40 to 50 ml/cm H2O
  4. What is normal compliance in an intubated female patient?
    35 to 45 ml/cm H2O
  5. What is the equation to calculate static compliance?
    Cs = (exhaled Vt)/(plateau pressure - EEP)
  6. What is the equation to calculate Airway Resistance?
    Raw = (PIP-Pplateau)/Flow
  7. What is normal airway resistance in a non-intubated patient?
    0.6 to 2.4 cm H2O/L/s flow
  8. What is the normal airway resistance in an intubated patient?
    ~6 cm H2O/L/s
  9. As endotracheal tube size decreases, airway resistance?
    increases
  10. An intubated 36 YO woman diagnosed with pneumonia is being ventilated with a volume of 0.5L (500 ml). The peak inspiratpry pressure is 24 cm H2O. Pplateau is 19 cm H2O and baseline pressure is zero. The inspiratory gas pressure is constant at 60 L/min (1 L/s). What is the static compliance of this patient?
    • Cs = Expired Vt/(Pplateau - EEP) or
    •      = 0.5/(19-0) = 0.0263 L/ cm H20 or 26.3ml/cm H20
  11. An intubated 36 YO woman diagnosed with pneumonia is being ventilated with a volume of 0.5L (500 ml). The peak inspiratory pressure is 24 cm H2O. Pplateau is 19 cm H2O and baseline pressure is zero. The inspiratory gas pressure is constant at 60 L/min (1 L/s). What is the airway resistance of this patient?
    • Raw = (PIP-Pplateau)/Flow
    • Raw = (24-19)/1 = 5 cm H20/L/sec
  12. What is the equation to calculate the time constant?
    Time Constant = C x R
  13. Convert 5 mm Hg to cm H2O.
  14. Calculate the time constant for a normal lung unit: Cs = 0.1 L/cm H2O  Raw = 1 cm H2o/(L/s)
  15. Calculate the time constant for a lung unit with decreased compliance and normal resistance: Cs = 0.025 L/cm H20  Raw = 1 cm H2O/(L/s).
  16. Calculate the time constant for a lung unit with normal compliance and increased resistance:  C = 0.1 L/cm H2O  Raw = 10 cm H2O/(L/s).
  17. Calculate the time constant for a lung unit with reduced compliance and increased resistance: Cs = 0.025 L/cm H20  Raw = 10 cm H2O/(L/s).
  18. Calculate the time constant for a lung unit with increased compliance and increased resistance: Cs = 0.15 L/cm H2O  Raw = 10 cm H20/(L/s).
  19. Calculate the time constant for a lung unit with increased compliance and normal resistance:  Cs = 0.15 L/cm H2O  Raw = 1 cm H2O/(L/s).
  20. 1 mm Hg = _____ cm H2O

    A) 1.30 atm
    B) 1034 cm H2O
    C) 1.36 cm H2O
    D) 1.63 cm H2O
    C) 1.36 cm H2O
    (this multiple choice question has been scrambled)
  21. The pressure difference between the alveolus (Palv) and the body surface (Pbs) is called ______________?

    A) transairway pressure
    B) transpulmonary pressure
    C) transrespiratory pressure
    D) Transthoracic pressure
    D) Transthoracic pressure
    (this multiple choice question has been scrambled)
  22. Define elastance.

    A) ability of a structure to return to it natural shape after stretching
    B) ability of a structure to stretch & remain in that position
    C) ability of a structure to stretch
    D) none of the above
    A) ability of a structure to return to it natural shape after stretching
    (this multiple choice question has been scrambled)
  23. Which of the following formulas is used to calculate compliance?

    A) C = Delta P/Delta V
    B) C = Delta V/Delta P
    C) Delta P = Delta V/C
    D) Delta V = C/Delta P
    B) C = Delta V/Delta P
    (this multiple choice question has been scrambled)
  24. Another term for airway pressure is?

    A) all of the choices
    B) airway opening pressure
    C) mouth pressure
    D) mask pressure
    A) all of the choices
    (this multiple choice question has been scrambled)
  25. Intraalveolar pressure (in relation to atmospheric pressure) at the end of inspiration during a normal quiet breath is approximately:

    A) 10 cm H2O
    B) +5 cm H20
    C) - 5 cm H2O
    D) 0 cm H20
    A) 10 cm H2O
    (this multiple choice question has been scrambled)
  26. Which of the following is associated with an increase in airway resistance?

    A) reducing the diameter of the ETT
    B) reducing the length of the ETT
    C) low airway opening pressures
    D) decreasing the flow rate of gas into the airway
    D) decreasing the flow rate of gas into the airway
    (this multiple choice question has been scrambled)
  27. Which of the following statements is true regarding negative pressure ventilation?

    A) chest cuirass is often used in treatment of hypovolemic patients
    B) tank respirators are particularly useful in the treatment of burn patients
    C) these ventilators mimic normal breathing mechanics
    D) the incidence of alveolar barotrauma is high with these devices compared with positive pressure ventilation
    C) these ventilators mimic normal breathing mechanics
    (this multiple choice question has been scrambled)
  28. PEEP is best defined as:

    A) zero baseline during exhalation on a positive pressure ventilator
    B) positive pressure during inspiration that is set by the person operating the ventilator
    C) positive pressure at the end of exhalation on a mechanical ventilator
    D) negative pressure during exhalation on a positive pressure ventilator
    C) positive pressure at the end of exhalation on a mechanical ventilator
    (this multiple choice question has been scrambled)
  29. Which of the statements is true regarding plateau pressure?

    A) plateau pressure is normally zero at end inspiration
    B) plateau pressure is a dynamic measurement
    C) plateau pressure is measured at the end of exhalation
    D) plateau pressure is used as a measure of of alveolar pressure
    D) plateau pressure is used as a measure of of alveolar pressure
    (this multiple choice question has been scrambled)
  30. One time constant should allow approximately what percentage of a lung unit to fill?

    A) 37%
    B) 63%
    C) 85%
    D) 100%
    B) 63%
    (this multiple choice question has been scrambled)
  31. A patient has a PIP of 30 cm H2O and a Pplateau of 20 cm H2O. Ventilator flow is set at a constant value of 30 lpm. What is the transairway pressure?

    A) 20 cm H2O
    B) 10 cm H2O
    C) 1 cm H2O
    D) 0.33 cm H2O
    B) 10 cm H2O
    (this multiple choice question has been scrambled)
  32. Name a commercially available ventilator that is entirely pneumatically powered.
    Bird Mark 7 or PB PR-2.
  33. Name a ventilator that is totally electrically powered.
    • Lifecare PLC-102
    • PB 2801 Homecare
    • Intermed Bear 33
  34. What type of ventilator delivers pressures below ambient pressure on the body surface and mimics the physiology of nomral breathing?
    Negative Pressure Ventilator
  35. Explain the operation of an externally mounted exhalation valve.
    During inhalation, gas flows through the expiratory valve line to the exhalation valve, closing it. On expiration, this flow ceases, the valve opens and the patient is able to exhale.
  36. What volume-displacement device creates a sine waveform for gas flow?
    Rotary Drive Piston
  37. A Drager E-4 ventilator is set to deliver a minute ventilation of 5 lpm. THe patient breathes six times in 1 minute and receives a mandatory breath of 500 ml with each breath. The ventilator detects the difference between the actual and the set minute volume and adds four more breaths (500 ml each) to make up the difference. Which of the following best describes this type of ventilator?

    A) Blank
    B) Blank
    C) Closed Loop
    D) Open Loop
    C) Closed Loop
    (this multiple choice question has been scrambled)
  38. The gas-conducting tubes that carry gas from the ventilator to the patient are referred to as the:

    A) Internal Pneumatic Circuit
    B) Control Circuit
    C) Control Scheme
    D) Patient Circuit
    D) Patient Circuit
    (this multiple choice question has been scrambled)
  39. A ventilator in which the gas that enters the patient's lungs is also the gas that powers the unit is referred to as a:

    A) Double Circuit Ventilator
    B) Direct Drive Ventilator
    C) Single-circuit ventilator
    D) Single Power Source Ventilator
    C) Single-circuit ventilator
    (this multiple choice question has been scrambled)
  40. In a spring-loaded bellows volume-delivery device, the amount of pressure is determined by the:

    A) Electrical power provided to the spring
    B) Tightness of the Spring
    C) Location of the bellows
    D) Volume setting on the ventilator
    B) Tightness of the Spring
    (this multiple choice question has been scrambled)
  41. Which of the following is an example of a flow control valve?

    A) Solenoid
    B) Linear piston
    C) Rotary Drive Piston
    D) Spring-loaded bellows
    A) Solenoid
    (this multiple choice question has been scrambled)
  42. An electrical current flows through an electromagnet and creates a magnetic field, pulling a plunger and opening a valve. This description best fits which of the following devices?

    A) Eccentric valve piston
    B) Digital valve
    C) Proportional Solenoid Valve
    D) Linear drive piston
    C) Proportional Solenoid Valve
    (this multiple choice question has been scrambled)
  43. The primary variable that the ventilator adjusts to produce inspiration is called the:
    Control Variable: the most common are pressure and volume.
  44. Equation of motion for the Respiratory System?
    Pvent + Pmuscles = (elastance x volume) + (resistance x flow)
  45. Adult Ventilator Tubing Compressibility
    ~2-3 ml per every 1 cm H20 pressure measured.
  46. The Pplat value is inaccurate when:
    the patient is actively breathing when the measurement is taken.
  47. Write the equation of motion.
    Pmus + Pvent = (V/C) + (R x Flow)
  48. Explain the term elastic recoil pressure in the equation of motion.
    The volume of air in the lungs depends on the elatic recoil, which is the pressure resulting from the alveolar tension on the volume within the alveoli.
  49. Which of the following phase variables is responsible for beginning inspiration?

    A) baseline variable
    B) trigger variable
    C) limit variable
    D) cycle variable
    B) trigger variable
    (this multiple choice question has been scrambled)
  50. List two other names for pressure-controlled ventilation.
    • pressure-targeted ventilation
    • pressure-controlled ventilation
  51. Which of the following variables will remain constant if airway resistance varies during a pressure-controlled breath?

    A) pressure
    B) pressure and expiratory time
    C) tidal volume and inspiratory flow
    D) inspiratory flow
    A) pressure
    (this multiple choice question has been scrambled)
  52. Compare pressure, volume & flow delivery in volume-controlled breaths and pressure-controlled breaths.
    With pressure-controlled breaths, the pressure waveform is constant in inspiration and volume and flow can vary. With volume-controlled breaths, volume delivery is constant & flow waveforms remain unchanged during inspiration - pressure can vary.
  53. Q=What are the two most common triggering variables?
    pressure & flow
  54. What happens in most ICU ventilators if the pressure limit is reached?

    A) inspiration ends & Vt is reduced; alarm sounds
    B) inspiration continues but pressure is limited & ventilator function does not change
    C) inspiration continues but pressure is limited
    D) alarm sounds
    A) inspiration ends & Vt is reduced; alarm sounds
    (this multiple choice question has been scrambled)
  55. Flow triggering gained widespread use by clinicians because:

    A) the therapist could set it more easily
    B) it is less expensive to manufacture
    C) it can be used with any mode of ventilation
    D) it caused less WOB for the patient
    D) it caused less WOB for the patient
    (this multiple choice question has been scrambled)
  56. A patient is being mechanically ventilated. THe Vt is set at 600 ml and the rate at 7 bpm. The low exhaled volume alarm, set at 500ml, suddenly is activated. The low pressure alarm is also activated. The volume monitor shows 0 ml. On the volume-time waveform, the expiratory portion of the volume curve plateaus and does not return to zero. The most likely cause of this problem is:

    A) loss of volume from tubing compressibility
    B) disconnection at the Y-connector
    C) Patient coughing
    D) leakage around the ETT
    B) disconnection at the Y-connector
    (this multiple choice question has been scrambled)
  57. Which ventilator uses a brief negative pressure at the beginning of the expiratory phase?

    A) Servo
    B) Puritan Bennett 840
    C) Cardiopulmonary Venturi
    D) Hamilton Galileo
    A) Servo
    (this multiple choice question has been scrambled)
  58. On a pressure-time waveform, the curve during expiratory phase does not return to the baseline rapidly as it normally would, It eventually reaches the baseline. THis may be a result of:

    A) an obstruction in the expiratory line
    B) PEEP set above zero baseline
    C) NEEP
    D) a leak in the circuit
    D) a leak in the circuit
  59. Normal Maximal Inspiratory Pressure
    -100 to -50 cm H2O
  60. Critical Maximal Inspiratory Pressure
    -20 to 0 cm H2O
  61. Normal Maximal Expiratory Pressure
    100 cm H2O
  62. Critical Maximal Expiratory Pressure
    10 to 15 cm H2O
  63. Normal VC
    65 to 75 ml/kg
  64. Critical VC
    <10 to 15 ml/kg
  65. Normal Tidal Volume
    5 to 8 ml/kg
  66. Critical Tidal Volume
    <5 ml/kg
  67. Normal Respiratory Frequency
    12 to 20 bpm
  68. Critical Respiratory Frequency
    >35 bpm
  69. Normal FEV1
    50 to 60 ml/kg
  70. Critical FEV1
    <10 ml/kg
  71. Normal Peak Expiratory Flow Rate
    250 to 600 lpm
  72. Critical Peak Expiratory Flow Rate
    75 to 100 lpm
  73. What is the best single indicator of the adequacy of ventilation?
    PaCO2
  74. What are two key indicators of the severity of acute hypoxemic respiratory failure?
    PaO2 and SpO2
  75. Which of the following indicates the presence of respiratory problems that might require respiratory support?

    A) VC of 2.1 L in a 70 kg man and PaO2 of 65 on RA and PaCO2 of 81 with a pH of 7.19
    B) MIP of -17 and VC of 2.1L in a 70 kg man and PaCO2 of 81 with a pH of 7.19 and PaO2 of 65 on RA
    C) MIP of -17 and PaCO2 of 81 with a pH of 7.19
    D) VC of 2.1 L in a 70kg man and PaO2 of 65 on RA
    C) MIP of -17 and PaCO2 of 81 with a pH of 7.19
    (this multiple choice question has been scrambled)
  76. Blood gas evaluation is  done for an unconscious patient in the ED. The results on RA are as follows:  pH 7.23  pCO2 81  pO2 43  HCO3 33 and SaO2 71%. With no other data available, which of the following forms of therapy is indicated?

    A) oxygen with a nonrebreathing mask
    B) IPPB treatment with albuterol
    C) mechanical ventilatory support
    D) CPAP mask
    C) mechanical ventilatory support
    (this multiple choice question has been scrambled)
  77. A 30 YO woman is seen in the ED. She has paralysis of the lower extremities that is progressively worsening. After several hours, during which she was monitored frequently, her VC has decreased to 12 ml/kg and MIP is -30 cm H2O. The results of blood gas analysis are not yet available. What type of therapy do you think this patient is most likely going to need?

    A) incentive spirometry to improve muscle strength
    B) narcotic blocking agent
    C) aerosolized bronchodilator administered with an MDI
    D) mechanical ventilatory support
    D) mechanical ventilatory support
    (this multiple choice question has been scrambled)
  78. A 28 YO man with botulism poisoning is beginning to develop progressive paralysis. The therapist has been monitoring the patient's MIP and VC every two hours. The most recent results show the patient continues to deteriorate:  MIP -17 cm H2O and VC 32 ml/kg. Which of the following could be appropriately recommended?

    A) medications to reverse the paralysis
    B) oxygen therapy
    C) mechanical ventilatory support
    D) gastric lavage
    C) mechanical ventilatory support
    (this multiple choice question has been scrambled)
  79. A 34 YO man is taken to the ED after and MVA. He is unconscious and unresponsive. ABG evaluation with the patient using a nonrebreathing mask show the following:  pH 7.09  pCO2  93  pO2 47  HCO3 27, Which of the following would you recommend?

    A) increase the oxygen flow to the mask
    B) administer bronchodilator therapy
    C) begin ventilatory support
    D) intubate and ventilate
    D) intubate and ventilate
    (this multiple choice question has been scrambled)
  80. A 60 YO man was admitted to the hospital yesterday for a suspected MI. Current ABG values on RA are as follows:  pH 7.47  pCO2 33  pO2 57  HCO3 25. Which of the following is the most appropriate form of therapy for this patient?

    A) NIV
    B) CO2/O2 therapy (5/95)
    C) oxygen therapy
    D) CPAP by mask
    C) oxygen therapy
    (this multiple choice question has been scrambled)
  81. A 48 YO woman is tachypneic, tachycardiac and pale. ABG results with the patient using a nonrebreathing mask are as follows:  pH 7.49  pCO2 32  pO2 45  HCO3 24. Which of the following is the most appropriate initial therapy for this patient?

    A) begin ventilatory support
    B) provide CPAP by mask
    C) administer bronchodilator therapy
    D) increase the oxygen flow to the mask
    B) provide CPAP by mask
    (this multiple choice question has been scrambled)
  82. Which of the following are goals of mechanical ventilation?

    A) provide support to the pulmonary system to maintain an adequate level of alveolar ventilation and reduce the WOB until the cause of the respiratory failure can be eliminated
    B) provide support to the pulmonary system to maintain an adequate level of alveolar ventilation and restore the ABG's to normal
    C) provide support to the pulmonary system to maintain an adequate level of alveolar ventilation and reduce the WOB until the cause of the respiratory failure can be eliminated and to restore the ABG's to normal
    D) provide support to the pulmonary system to maintain an adequate level of alveolar ventilation and to restore the ABG's to normal
    C) provide support to the pulmonary system to maintain an adequate level of alveolar ventilation and reduce the WOB until the cause of the respiratory failure can be eliminated and to restore the ABG's to normal
    (this multiple choice question has been scrambled)
  83. A 74 YO patient with COPD who has acute on chronic respiratory failure is supported with NIV. The patient is becoming more confused. Blood gas values are as follows:  pH 7.21  pCO2 58  pO2 45 and HCO3 23. Which of the following would be appropriate treatment for this patient?

    A) switch to invasive ventilation
    B) increase oxygen delivery
    C) ask the patient is he is comfortable with the mask
    D) ask the physician for a sedative
    A) switch to invasive ventilation
    (this multiple choice question has been scrambled)
  84. A 14 YO boy who has been previously diagnosed with mild persistent asthma has a PEFR of 100 lpm. This indicates which of the following?

    A) increased lung compliance
    B) heart failure
    C) increased airway resistance
    D) inability to take a deep breath and cough
    C) increased airway resistance
    (this multiple choice question has been scrambled)
  85. After oxygen is administered, a patient's HR changes from 110 to 85. the initial tachycardia was most likely caused by which of the following:

    A) hypercapnia
    B) anxiety
    C) hypoxemia
    D) pain
    C) hypoxemia
    (this multiple choice question has been scrambled)
  86. A 34 YO patient who was in an MVA is admitted to the hospital with crushed chest injuries and a fractured tibia. Two days later, the PaO2 is 56 while he is breathing 80% oxygen and the RR is 30 to 34 bpm. Based on the hx and findings, which of the following does the patient most likely need?

    A) invasive ventilation
    B) CPAP with oxygen
    C) noninvasive ventilation
    D) 100% oxygen
    A) invasive ventilation
    (this multiple choice question has been scrambled)
  87. T/F:  Although manipulation of a mechanical ventilator can be helpful in reducing intracranial pressure, this procedure has not been shown to imporve long-term outcomes.
    True
  88. Opting not to provide mechanical ventilation for an apneic patient would be appropriate under what circumstances?
    When the patient has a living will or a surrogate states that the patient does not want to be intubated and ventilated. Another possibility is an advanced stage of disease in a terminal illness.
  89. In which of the following would you try NIV?

    A) A patient in whom BP is 65/35, HR is 150 and RR is 34
    B) A patient who nearly drowned who has copious amounts of frothy, white secretions
    C) A patient with COPD and RLL oneumonia with respiratory acidosis and increased WOB
    D) a 5 YO child who has aspirated a piece of chicken and is having trouble breathing
    C) A patient with COPD and RLL oneumonia with respiratory acidosis and increased WOB
    (this multiple choice question has been scrambled)
  90. Which of the following would you use for a trauma victim with crushed chest injuries?

    A) noninvasive ventilation
    B) negative pressure ventilation
    C) pressure-cycled ventilator
    D) VC-CMV
    D) VC-CMV
    (this multiple choice question has been scrambled)
  91. A patient with hiccups is ventilated in the VC-CMV mode. Every time he hiccups, he triggers the ventilator. What would you recommend?

    A) Use VC-SIMV
    B) paralyze the patient and control ventilation
    C) use PSV
    D) use PC-CMV
    A) Use VC-SIMV
    (this multiple choice question has been scrambled)
  92. A patient with severe tetanus needs ventilatory support. Which of the following modes would you recommend?

    A) PS with CPAP
    B) paralzye and sedate the patient: control ventilation using volume control (VC-CMV)
    C) VC-SIMV
    D) PC-CMV
    B) paralzye and sedate the patient: control ventilation using volume control (VC-CMV)
    (this multiple choice question has been scrambled)
  93. In which of these four circumstances is it appropriate to select PSV?

    A) as a method of weaning, to overcome the WOB through the ETT and the circuit and for patients on PSV using the SIMV mode
    B) to overcome the WOB through the ETT and circuit, for patients on PSV using the SIMV mode and for long term patient support
    C) as a method of weaning, for patients on PSV using the SIMV mode and for long term patient support
    D) as a method of weaning, to overcome the WOB through the ETT and the circuit, for patients on PSV using the SIMV mode and for long term patient support
    D) as a method of weaning, to overcome the WOB through the ETT and the circuit, for patients on PSV using the SIMV mode and for long term patient support
    (this multiple choice question has been scrambled)
  94. A patient on PC-CMV has widely fluctuating changes in Raw because of secretions and bronchospasm. The tow tidal volume alarm is activated every few hours: the set pressure is 18 cm H2O. The physician is concerned about consistency in ventilation. What would you recommend?

    A) switch to VC-CMV
    B) sedate the patient
    C) switch to PSV
    D) increase the set pressure
    A) switch to VC-CMV
    (this multiple choice question has been scrambled)
  95. A patient with ARDS has a Pplat of 30 cm H2O and a peak inspiratory pressure of 39 cm H2O. Vt is 0.7 on VC-CMV. The decision is made to keep pressures at a safe level/ What pressure would you set and why?
    A pressure of 30 cm H2O to start would provide approximately the same Vt delivery in the VC-CMV moce and would be a safe starting point. This patient requires high pressures for delivery of Vt. Palv should be kept below 30 cm H2O.
  96. A patient receiving VC-CMV is actively triggering each breath. The therapist notices that the patient is using accessory muscles during the entire inspiratory phase. The therapist sees that the pressure-time curve has a negative deflection before inspiration and has a concave appearance during inspiration. What is the apparent problem in this situation?
    Apparently the ventilator has a fixed flow rate and pattern during inspiration that is not adequate for this patient's needs. The therapist should increase the inspiratory flow and see whether this solves the problem. Another solution would be to switch to a newer generation ventilator that allows additional flow on demand during VC-CMV.
  97. A patient has recovered from a severe pneumonia that required 8 days of PC-CMV. The patient is now conscious and responsive. She is triggering every breath and has a strong cough. What should the therapist suggest to the physician?
    At this point several possibilities exist. THe patient might be changed to PC-SIMV with a lower mandatory rate or PSV might be an option. The latter would allow the patient control over breathing. However, if PSV is used, the SpO2, Vt and Ve would need to be monitored closely. VSV might also be used. All these options would allow for more spontaneous ventilation and still provide monitoring of the patient.
  98. A physician is concerned about the high pressures required to perform ventilation for a patient with terminal cancer and severe lung scarring. The lungs are very stiff and fibrous. The physician is also concerned about maintaining a normal CO2 in this patient. What mode might be appropriate for this patient and why?
    A dual control mode that limits pressure (e.g., PRVC) might be appropriate. This mode would limit pressure delivery and could also target volume in an effort to maintain the patient's ventilation.
  99. A patient with ARDS is to be changed from CPAP of 10 cm H2O to VC-CMV. She is 5'4" tall and weighs 195 lbs. What tidal volume and rate would you set and why? Would pressure-controlled ventilation be appropriate for this patient?
    The patient's IBW is 105 + 5(64-60) = 125 lbs or 56.8 kg, therefore she has alarge BSA. Her estimated VE (assuming normal body temperature) is 3.5 x 1.94 or about 6.8 lpm. If the VE had been based on IBW, it would have underestimated her metabolic rate. However, her Vt must be based on IBW. Using the calculared IBW, an appropriate Vt for a patient with ARDS would be in the range of 4 to 8 ml/kg. For this patient the range would be 230 to 450ml. A respiratory rate of 15 (using 8 ml/kg) to 30 (using 4 ml/kg) would be in the target range. A higher rate must accompany a lower Vt. It might be appropriate to start in the middle of this range. PV would probably provide patient comfort and would be suitable for this patient, particularly based on her diagnosis. The pressure could be set to target the desired Vt.
  100. NIV in being initiated on a 54 YO man with a hx of COPD. He has an IBW of 70 kg. The initial settings are IPAP 8 cm H2O and PEEP 3 cm H2O. THe patient's Vt on these settings is 280 ml
    Try increasing the IPAP to 11 cm H2O and reevaluate the patient. The Vt should be closer to the 550 ml (range 8 to 10 ml/kg IBW) and the spontaneous rate should be below 25.
  101. A patient with RLL pneumonia and a temperature of 100 degrees F must be mechanically ventilated. How should the initial Vt be set?
    The Vt should be increased by 10% or 5% for every degree >99 degrees F.
  102. A physician requested that he patient be switched from PC-CMV to guarantee volume delivery. Ventilator parameters are VC-SIMV + PSV; Vt = 0.6; f = 20; flow = 60 lpm (using constant waveform); PSV = 27; PEEP = 8. PIP = 56 cm H2O and Pplat - 43. The physician asked the RT to find a way to refuce pressures without changing the Vt. What is a possible solution?
    Changing to a descending waveform with volume ventilation would change the pattern of pressure delivery, resulting in a decrease in the PIP. This was a real situation. In this case, the resulting PIP was 41 cm H2O and the Pplat was 32 cm H2O without any other changes.
  103. A ventilator with PRVC with a PEEP of 5, a set Vt of 650 ad an upper pressure limit of 30 cm H2O. Initially the pressure required to deliver the Vt was 20 cm H2O. Now it is taking 24 cm H2O to deliver the volume. What changes have probably occurred in the pateint's lung characteristics?
    The lung characteristics are deteriorating: this is Raw is increasing or lung compliance is decreasing or both.
  104. What ventilator mode is patient-triggered, pressure targeted, flow-cycled and also targets a set Vt?
    volume support ventilation
  105. The flow-time and pressure-time curves are viewed during PC-CMV ventilation with an apneic patient. What is the Pplat?
    ~ 14 cm H2O
  106. The pressure time curve above is observed during PSV. What is causing the curve to appear like this?

    A) a leak in the circuit
    B) no sloping in the presence of increased airway resistance
    C) active patient exhalation
    D) active inhalation
    C) active patient exhalation
    (this multiple choice question has been scrambled)
  107. A male patient has a BSA of 1.5 m2, is 5'8" and weighs 175 lbs. The patient has a hx of lung damage resulting from old TB scars. What ventilator settings (VE, Vt and f) would you select for this patient?
    • initial VE = 4 x 1.5 = 6 lpm
    • Vt is based on IBW:  IBW = 106 + 6(8) = 154 lbs or 70 kg. Vt range of 4 to 8 ml/kg = 280 to 560 ml. Example: at 6 ml/kg, initial Vt =420 ml. Rate selected using Vt and VE.  f = VE/Vt = 6/0.42 = 14, f = 14
  108. A patient with COPS is being ventilated with a Puritan Bennett 840 ventilator. Ventilator parameters are as follows: VC-CMV; flow = 40 lpm with descending flow pattern; Vt = 0.65; FiO2 = 0.3, At 2 pm, total f = 10 bpm, PIP = 28 cm H2O. There are no assisted breaths and the pressure-time curve is normal. At 4 pm, total f = 20 bpm; PIP = 37cm H2O, the patient is actively assisting and using accessory muscles to breathe and the pressure-time graphic shows a concave appearance. What would you do to correct the situation?
    Overa 2 hour period, the VE increased from 6.5 lpm to 13 lpm. THe patient is using accessory muscles to breathe and the pressure-time curve indequates an inadequate flow. PIP has also increased. These findings suggest the presence of air-trapping, therefore evaluate for the presence of intrinsic PEEP. Increase the inspiratory flow and reassess the pressure-time curve. Assess the patient's ventilatory to determine whether the problem persists. Another possibility is to switch to VC-SIMV + PSV, however inspiratory glow would still need to be increased and PSV would need to be set at an appropriate level. Other questions might also be asked: what is the SpO2?  Have the ABG's changed? Have the breath sounds changed? What does the flow-time curve look like?
  109. An 83 YO man is being treated in the ED. his wife, who brought him in, states, "he's so SOB and pale, I was worried." Oxygen by 28% air-entrainment mask is begun. The patient is given an IPPB treatment with albuterol. Despite continued therapy, the patient does not improve and continues to use accessory muscles to breathe. He is diaphoretic and pale and his temperature is 102 degrees F. The decision in made to begin NIV. A BIPAP unit is set up with initial pressures of IPAP = 6 and EPAP of -2. These are then adjusted based on pulse oximetry and the patient's RR. With an IPAP to EPAP ratio of 12 cm H2O to 4 cm H2O and a measured FiO2 of 0.3, the patient has a rate of25 bpm and an SpO2 of 87%. Vital signs, SpO2 and RR remain fairly stable. Two hours later the patient's RR has increased to 35 bpm. ABG's reveal Ph 7.21  pCO2 05  pO2 47  HCO3 40. Repeated adjustments to the IPAP:EPAP ratio fail to improve the patient's condition. The decision is made to intubate him and proide him with volume-targeted ventilation. The patient is 5'8" and weighs 148 lbs (IBW = 70 kg). BSA = 1.78 m2. The SIMV mode is selected. What initial Vt, VE and f would your select? After initiating ventilation, the following paramaters are noted: PIP 33 cm H2O  Pplat 25 cm H2O Pta = 33-15 = 8 cm H2O. The patient is spontaneously breathing an additional 10 bpm with a Vt of 200 ml. The decision is made to add pressure support for the spontaneous breaths to overcome the WOB imposed by the artificial airway. What is an estimate resistance on this patient, assuming a constant flow of 80 lpm is used for calculation? Where would you set pressure support?
    A number of solutions are possible for this problem. The following answer is provided as one option. Initial Vt is selected at 6 ml/kg (420 ml). Because this patient has a hx of COPD, a lower Vt was selected to reduce the risk of lung injury. VE is set at 8 lpm: 4 x BSA = 4 x 1.78 = 7.12 lpm, Increase VE by 5% oer degree F. Increase by 1.05 lpm to a total VE of 8.2 lpm. Rate is set at 19 bpm (VE/Vt = f) Flow is set at 80 lpm using the descending flow pattern. FiO2 is set at 0.5 initially. (NoteL because this patient is breathing spontaneously, a lower g and VE could be used, depending on the clinician's preference. The FiO2 could be lower, as well. The setting selected here would provide a minimum safe initial form of ventilation and could be adjusted based on patient assessment.  Resistance is estimated at Pta/Flow or 8cm H2o/80 lpm = 8cm H2o/1.33 lps = 6 cm H2o.L/sec. The answer is only an estimate because the flow is not constant. Pressure support is set at 6 cm H2O.
  110. A 50 YO man is receiving VC-CMV following surgery for a bowel resection. He is in the PAR. The patient has an IBW of 80 kg and a BSA of 1.8 m2. What initial settings would be appropriate?
    Post-op patients and victims of drug overdose are examples of patients who are most likely to have normal lungs yet still require ventilation. Appropriate settings for normal lungs are as follows:  VC-CMV or PC-CMV; Vt 5-8 ml.kg; f 10 to 15 bpm; descending or constant waveform; TI ~ 1 second initially; PEEP 5 cm. Keep Pplat less than 30 cm H2O. FiO2 <0.5 (titrate to patient's normal, maintain PaO2 > 70 mm Hg amd SpO2 >92%. For this patient, a Vt range of 400 to 640 ml would be appropriate. VE would equal 4x 1.8 = 7.2 lpm. Rate would range from 11 to 18 bpm. An FiO2 of 0.5, PEEP of 3 cm H2O,a descending flow ramp and VC-CMV would all be appropriate settings.
  111. FiO2 should be measured with an oxygen analyzer:
    A) at least every 24 hours and continuously with infants
  112. A patient has a Pta of 5 cm H2O. Three hours later a high pressure alarm activates. The patient's Pta is now 14 cm H2O. What is the most likely cause of this change?

    A) VC-SIMV
    B) 250 to 600 lpm
    C) secretions in the airway
    D) The volume of air in the lungs depends on the elatic recoil, which is the pressure resulting from the alveolar tension on the volume within the alveoli.
    C) secretions in the airway
    (this multiple choice question has been scrambled)
  113. A 35 YO man with ARDS is being ventilated with a Vt of 400 ml. The patient's IBW is 176 lbs (80 kg). The HME has a volume of 50 ml. What is the approximate alveolar volume of one breath for this patient?
    260 ml

    Vdant is equal to about 180 ml (80 kg IBW x 2.2 lbs/kg = 176 lbs.) With an ETT in place, the Vdant is reduced by albout half to 90 ml. The HME adds about 50 ml of mechanical deadspace. Vd is about 140ml. VD - Vt = VA;  VA = 400-160 = 260 ml.
  114. The figure below shows pressure-time curves obtained during PC-CMV. What is the Pplat?
    30cm H2O

    When the flow is zero (before exhalation begins) the pressure on the pressure time curve for the same time interval will be Pplat.
  115. A PE of the chest is performed on a mechanically ventilated patient. Breath sounds and percussion are normal except over the RML, where late inspiratory crackles are heard. This area is dull to percussion. An evaluative CXR reveals infilatrates in the RML. Based o these findings alone, what is the most likely problem?
    RML pneumonia
  116. The following values are obtained from a patient's ventilator flow sheet:
     Time     Vol     PIP     Pplat
     0100     850    35       33
     0200     850    39       32
     0300     850    42       33

    What is likely occurring?
    The Raw is getting worse.
  117. A static curve for Cs and Cd reveals a widening gap between the two curves. What does this probably represent?
    An increase in Raw, as might occur with bronchoconstriction or mucus plugging.
  118. A patient has an IBW of 150 lbs, a Vt of 0.55L and an f of 8 bpm. What is the estimated alveolar volume?
    Vt = 0.55L Vdant = 0.15L  Va= (0.55-0.15) x 8 bpm = 3.2L.
  119. After listening with a stethoscope over the trachea during VC-CMV, the therapist hears a slight leak at the end of inspiration on an orally intubated patient. What change should the therapist make?
    check cuff pressure and delivered volume.
  120. A 215 lbs, 6'4" man has a size 7 ETT in place. Cuff pressure is 35cm H2O. The set Vt is 900ml and the delivered Vt is 800ml. The patient is likely to need mechanical ventilation for a week. What would you recommend?
    change the ETT to a size 8.
  121. The following data were obtained for a patient on PC-CMV:
     Time     Set Pressure     Vt
     2100         20               550
     2300         20               575
     0100         20               620

    What do you think is causing the change ib Vt and what should the therapist evaluate?
    The change in Vt may be the result of an improvement in lung characteristics. (e.g., a decrease in Raw or an improvement in CL. Listen to the breath sounds, evaluate the flow-time and volume-time curves and check the current acid-base status. Changes in Vt may lead to respiratory alkalosis. The preset pressure may need to be reduced.
  122. A high volume/low pressure cuff has a pressure of 15 cm H2O as measured with a BP manometer technique. The therapist does not hear a leak when listening over the tracheal area with a stethoscope. What should the therapist do?
    Maintain the current pressure because this will augment tracheal perfusion.
  123. When changing the tape on the ETT, the therapist accidentally cuts the pilot balloon line. This problem can be corrected by:
    Using a stopcock, blunt-tipped needle and syringe to reinflate the cuff and keep it inflated.
  124. What causes the pressure spike indicated by arrow A on the pressure-time waveform?
    The arrow indicates an active exhalation by the patient.
  125. What ventilator parameter might be adjusted to eliminate the problem of the patient's active exhalation?
    The flow cycle criterion might be increased to a higher percentage so the the TI is shorter.
  126. What caused the flow waveform during exhalation at arrow B?
    The expiratory flow pattern at arrow B indicates air trapping.
  127. What parameters might be adjusted on the ventilator to eliminate the problem of air-trapping?
    Shortening the TI might allow a longer time for exhalation and eliminate the problem. Suctioning of the patient or administration of bronchodilato might be indicated to reduce Raw. Because this is PSV, reducing the set pressure might affect both Vt and VE, thus reducing air trapping. However, this type of adjustment would have to be monitored to ensure that the patient is still adequately ventilated.
  128. What pulmonary change is suggested by the exhalation volume waveform indicated by arrow C?
    The prolonged exhalation of volume suggests airway resistance: checking a flow-volume loop might confirm this finding.
  129. Is the flow-cycle percent set at a high or low percentage of peak flow?
    It is set at a high percentage of the peak flow.
  130. Is there any indication of inadequate inspiratory flow?
    The pressure-time curve does not have a concave appearance, however, the curve would not take this shape with pressure-targeted ventilation. The patient can get as much flow as needed and the pressure will be maintained. The ventilator would increase flow to achieve set pressure if the patient were actively inhaling, as long as a rise time or slope does not reduce inspiratory flow, inadequate flow should not be a problem.
  131. A ventilator is set for volume-targeted ventilation, constant flow and control mode. What will happen to the PIP, Pplat, TI  and Vt if CL decreases? (Assume that the pressure limit is not reached?
    PIP and Pplat will increase and TI and Vt will stay the same.
  132. A ventilator is set for pressure-targeted ventilation, patient triggering and time cycling. What will happen to the set pressure, TI and Vt if CL increases? (Assume that the pressure limit is not reached)
    Pset and TI will remain constant but Vt will increase.
  133. A patient receiving pressure ventilation has a CL of 15 ml/cm H2O. The pressure is set at 35 cm H2O. The ventilator is time cycled at 2 seconds. Flow drops to zero beofre the end of inspiration. What will the Pplat be?
    Palv is 35 cm H2o. Compliance has nothing to do with the answer. We know the pressure because the flow drops to zero during inspiration (the alveolar and preset pressures equilibrate.)
  134. A patient receiving pressure ventilation has a CL of 15 ml/cm H2O. The pressure is set at 35 cm H2O. The ventilator is time cycled at 2 seconds. Flow drops to zero beofre the end of inspiration. What is estimated volume delivery?
    Vt will be 0.424 L  Volume = Pressure x Compliance

    Volume = 35 cm H2O x 0.03ml/cm H2O = 525 ml (0.525 L)
  135. A patient receiving pressure ventilation has a CL of 15 ml/cm H2O. The pressure is set at 35 cm H2O. The ventilator is time cycled at 2 seconds. Flow drops to zero beofre the end of inspiration. CL changes to 30 ml/cm H2O with improvement in the patient's lung condition. What will happen to the flow and volume delivery?
    After compliance improves, volume delivery will increase. Volume = 35 cm H2O x 0.03 ml/cm H2O = 1.05 L (1050 ml). Pta will be approximately the same because the generating pressure is the same and Raw is not increased. (Actually Pta will decrease slightly as the flow drops off when Palv approaches the preset pressure).
  136. A patient receiving pressure ventilation has a CL of 15 ml/cm H2O. The pressure is set at 35 cm H2O. The ventilator is time cycled at 2 seconds. Flow drops to zero beofre the end of inspiration. CL changes to 30 ml/cm H2O with improvement in the patient's lung condition. How would you change volume delivery to return it to its previous level?
    Reduce the preset pressure until the desired Vt is achieved. (This would be approximately half the previous setting because compliance doubled (about 17  to 18 cm H2O).
  137. Explain the normal components of the capnograph.
    The capnograph waveform is divided into 4 phases. In Phase I, the initial gas exhaled is from the conducting airways, which contains low levels of CO2. During Phase II, alveolar gas containing CO2 mixes with gas in the anatomical airways and the CO2 concentration increases. In Phase III, the curve plateaus as alveolar gas is exhaled (this phase is often referred to as the alveolar plateau). Note that the concentration of CO2 at the end of the alveolar phase (just before inspiration begins) is called the "end-tdial CO2" or "PetCO2". On inspiration (Phase IV), the concentration falls to zero.
  138. What is the pressure-time product? How can this variable be used in the management of mechanically ventilated patients?
    The pressure-time product, which is an assessment of the transdiaphragmatic pressure during the inspiratory portion of the breathing cycle, is a way of estimating the contribution of the diaphragm during inspiration.
  139. Which of the following conditions will adversely affect pulse oximeter readings?

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