Respt 120

  1. CPAP
    • Improves oxygenation
    • Used to treat obstructive sleep apnea
    • Also used to treat patients with COPD
  2. Noninvasive positive pressure ventilation
    • Used for patients with respiratory failure caused by various neuromuscular disorders, chest wall deformities, COPD, central ventilatory control abnormalities, and acute cardiogenic  pulmonary edema
    • Can reduce the need for intubation in 60 to 75% of patients
  3. Advantages of Noninvasive positive pressure ventilation!
    • Avoids complications associated with artificial airways
    • Provides flexibility in initiating and removing mechanical ventilation
    • Reduces requriements for heavy sedation
    • Preserves airway defense, speech, and swallowing mechanisms
    • reduces need for invasive monitoring
  4. Disadvantages of Noninvasive positive pressure ventilation!
    • Can cause gastric distention
    • skin pressure lesions
    • Facial pain
    • Dry nose
    • eye irritation
    • Discomfort
    • Claustrophobia
    • poor sleep
    • mask leaks can occur
  5. Full ventilatory support
    • Provides all the energy necessary to maintain effective alveolar ventilation
    • Provided when ventilatory rates are high (8 breaths/min or more) and tidal volume is adequate for the patient
  6. Partial ventilatory support
    Any degree of mechanical ventilation in which set machine rates are lower than 6 breath/min and the patients partipates in the work of breathing to help maintain effective alveolar ventilation
  7. Patient lung characteristics in volume controlled ventilation!
    • Reduction in lung or chest wall compliance produce higher peak and plateau pressures
    • Increases compliance produces lower peak and plateau pressures
    • Increased airway resistance produces a higher peak pressure
    • Reduction in airway resistance produces lower peak pressures
  8. Inspiratory flow pattern in volume controlled ventilation!
    • Peak pressures is higher with a constant flow and lower with a decelerating flow pattern
    • Decelerating flow pattern has a higher mean airway pressure
    • Constant flow generates the lowest mean airway pressure
    • High inspiratory gas flow creates a higher peak pressure
  9. Volume setting in volume controlled ventilation!
    • High volume produces higher peak and plateau pressures
    • Low volumes produce lower peak and plateau pressures
  10. PEEP in volume controlled ventilation!
    Increasing PEEP increases the peak and mean  pressures
  11. Auto PEEP in volume controlled ventilation!
    Increases in auto PEEP increases the peak inspiratory pressure
  12. Pressure setting in pressure controlled ventilation!
    • Higher pressure setting produce larger volumes
    • Lower pressure setting produce lower volumes
    • Increasing the PIP while maintaining a constant EEP increases volume delivery
  13. Pressure gradient in pressure controlled ventilation!
    Increasing EEP (PEEP + auto PEEP) while keeping PIP constant reduces the pressure gradient (PIP - EEP) and lowers volume delivery
  14. Patient lung characteristics in pressure controlled ventilation!
    • Reduced compliance results in lower volumes
    • Increased compliance results increased volumes
    • Increased airway resistance (RAW) results in lower volume delievery
    • Reduction in airway resistance results in higher volume delievery
  15. Inspiratory time in pressure controlled ventilation!
    When the inspiratory time is extended, volume delievery increases
  16. Patient effort in pressure controlled ventilation!
    Active inspiration by the patient can increase volume delievery
  17. Continuous mandatory ventilation
    • All breaths are mandatory and can be volume or pressure targeted
    • Breaths can also be patient triggered or time triggered
  18. Intermitted mandatory ventilation
    • Involves periodic volume or pressure targeted breaths that occur at set intervals (Time triggering)
    • The patient can breath spontaneously between mandatory breaths
  19. CPAP may be helpful for...
    Improving oxygenation in patients with refractory hypoxemia and a low FRC, which can occur with a acute lung injury
  20. Pressure support ventilation
    A pressure support breath is patient triggered, pressure limited, and flow cycled
  21. Advantages of volume targeted or pressure targeted continuous mandatory ventilation! (CMV)
    • Set minimum ventilation with volume tregeted breaths
    • Guaranteed volume or pressure with each breath
    • May synchronize with patient efforts
    • Patient may establish rate
    • Can provide full support in patients who are not breathing spontaneously
  22. Advantages of volume targeted or pressure targeted synchronized intermittent mandatory ventilation! (SIMV)
    • May lower mean airway pressure
    • Variable work of breathing for patient may maintain muscle strength and reduce muscle atrophy
    • Can be used for weaning
    • May reduce alkalosis associated with CMV
    • Full or partial support can be adjusted to meet patients needs
    • Sedation and paralysis are not requried
  23. Metabolic rate is directly related to...
    Body mass and surface area
  24. Minute Ventilation
    • Men- Ve = 4 x body surface area (BSA)
    • Women- Ve = 3.5 x body surface are (BSA)
  25. Calculating ideal body weight!
    • Women: IBW= 105 +5(H-60)
    • Where H is hieght in inches
    • Men: IBW = 106 + 6(H-60)
  26. Tubing compliance
    • Reflects the volume (in milliliters) of gas compressed in the ventilator circuit
    • Ct= change in volume divided by change in pressure
  27. When setting tidal volume and rate, the goal is not to focus so much on the exact Vt and rate but to focus...
    • On using setting that do not harm the patient
    • Maintaining plateau pressures lower than 30 cm H2O is very important
    • In some cases let PaCO2 rise and pH fall outside the patients normal values to avoid lung injury
  28. When determining tidal volume for ventilated patients...
    • A range of 5 to 8 mL/kg of IBW is typically used for adults
    • 4 to 8 mL/kg IBW for infants and children
    • 6 to 12 ml/kg IBW
    • 5-10 ml/kg IBW
  29. Mechanical dead space
    • The volume of gas that is rebreathed during ventilation
    • Adding dead space will increase dead space
    • App 6 inch of tubing will increase CO2 by 2 to 3 ml/Hg
  30. Gas flow during controlled mechanical ventilation
    • High flows shorten Ti and may result in higher peak pressures and poor gas distrubution
    • Slower flows may reduce peak pressures, improve gas distrubution, and increase Paw
    • Shorter Te can lead to air trapping and longer Ti may cause cardiovascular side efects
  31. A long Ti (requring 3 to 4 constants) has been shown to improve...
    • Ventilation in nonhomogeneous lungs like those seen in ARDS
    • good for patients with increased resistance
  32. Fast Ti flows (requring fewer time constant to fill the lungs) may benefit...
    Patients with increased airway resistance as in COPD, providing longer Te, which in turn will reduce or prevent the risk of air trapping
  33. Inspiratory pause
    A maneuver that can be performed by preventing the expiratory valve from opening for a short time at the end of inspiration
  34. The inspiratory pause maneuver is used to obtain...
    Measurements of Pplateau, which helps to estimate alveolar pressure for the calculations of static compliance
  35. The inspiratory pause provides a longer inspiratory time, which in turn provides...
    • Optimum V/Q matching
    • Reduces dead space to tidal volume ratios
  36. In any pressure targeted breath the difference in what determines the set Vt delievery?
    Pressure between baseline (PEEP + auto PEEP) and PIP
  37. There are two ways to set the pressure in pressure targeted breath to provide the desired Vt!
    • One way is to deliever a volume targeted breath to the patient at the desired Vt and measure the plateau and baseline pressures
    • A second method to intiate pressure ventilation is to start at a low pressure (10-15 cm H2O) and check the Vt before readjusting the pressure to attain the desired volume
  38. Pressure support ventilation
    • The pressure is set at a level sefficient to prevent a fatiguing workload on the respiratory muscles
    • Set the initial PSV level to equal the transairway pressure
  39. The goal of adjusting pressure support ventilation!
    • To help increase Vt (4-8 mL/kg)
    • To decrease respiratory rate (to <30 breaths/min
    • To decrease the WOB associated with breathing through an artificial airway
  40. The goal of setting a specific FiO2 for a patient is to...
    Achieve a clinically acceptable arterial oxygen tension(60-100 mm Hg)
  41. If the PaO2 is not within the desired range, The equation for FiO2!
    Image Upload 1 
  42. Hypoxic Drive
    • If a baseline ABG is not available, it is advisible to select a high initial FiO2 setting > 0.50
    • This can be a way of restoring normal oxygenation and replacing tissue oxygen storage when oxygen debt and lactic acid accumulation has occured 
  43. Extended use of 100% O2 is not recommended because...
    It can lead to absorption atelectasis and long term oxygen toxicity
  44. Sensitivity setting
    • Flow triggering is set in a range of 1 to 10 L/min below the base flow
    • Pressure sensitivity is common between -1 and -2 cm H2O
  45. When a FiO2 greater than 0.50 is requried to maintain oxygenation...
    PEEP may be indicated
  46. Many clinicians prefer using flow triggering because...
    It provides a slightly faster response time compared with pressure triggering
  47. If auto PEEP is present...
    Patients might have trouble triggering a breath
  48. Intrinsic PEEP can occur in three situation!
    • Strong active expiration
    • High minute ventilation where Te is too short
    • expiratory flow limitations due to increased airway resistance
  49. Humidity
    The humidification system used during mechanical ventilation should provide at least 30 mg H2O/L of absolute humidity at a temperature range of about 31 to 35 degrees C for all available flows up to Ve of 20 to 30 L/min
  50. Heated Humidifiers devices!
    • Passover
    • Vapor phase
    • Wick
    • Active heat and moisture exchange
  51. Heated humidifiers
    Typically include a servo controlled heater with a temperature probe that is placed close to the patient airway
  52. Whenever the temperature in the patients circuit is less than the temperature of the gas leaving the humidifier...
    • Condensate accumulates in the circuit
    • This will increase as the room temp becomes cooler
  53. To assess whether a humidity deficit is present...
    The therapist should check the patients secretions
  54. Heat moisture exchangers
    Can provide up 10 to 14 mg/L of water at tidal volumes of 500 to 1000 mL
  55. The dead space for most HMEs ranges from...
    50 to 100 mL
  56. Contraindications for heat moisture exchangers!
    • The presence of thick, copious, or bloody secretion.
    • The patients exhaled tidal volume is less than 70% of inhaled Vt
    • Body temp below 32* C
    • Spontaneous Ve is greater than 10 L/min
    • An aerosolized medication must be given
    • Very small Vt must be delievered
  57. Most HMEs have a resistance to flow of...
    Between 2.5 and 3.5 cm H2O/L/min
  58. Low pressure alarms
    • Usually set about 5 to 10 cm H2O below PIP
    • These alarms are useful for detecting patient disconnection and leaks in the system
  59. High pressure alarms
    • Set about 10 cm H2O about PIP
    • Usually end inspiration when activated
  60. Low PEEP/CPAP alarms
    • Usually set about 2 to 5 cm H2O below the PEEP
    • Activation of these latter alarms usually indicates the presence of a leak in the circuit
  61. Low minute ventilation alarm
    10 to 15% below average minute volume
  62. Sigh breaths
    • A deep breath that occurs regular as a part of a normal breathing patterm
    • Reduces atelectasis
  63. Sighs or deep breaths may be appropriate in the following situations!
    • Before and after suctioning
    • Before and after bronchoscopy
    • During an extubation procedure
    • During CPT
    • During low Vt ventilation
    • As a recruitment maneuver in some patients with ARDs
  64. Final consideration in ventilator equipment setup!
    • Check ventilator and circuit function
    • Fill the humidifier with sterile water and set the humidifier temp so that the final gas temp at the airways will be 31 to 35 *C or place an HME in line
    • Place a temperature monitoring device near the patients connector when heated humidifier is used
    • Check the FiO2, set Vt and F
    • Adjust the alarms
    • Ensure that the patient is connected to an electrocardiographic monitor
    • Have an emergency airway tray avilable in case the patient airway is removed or damanged
    • Check that the suctioning equipment is available and functioning
    • Select a volume monitoring device and an oxygen analyzer if one is not available with the ventilator
    • Ensure that a manual resuscitation is available
  65. Once the decision has been made to connect the patient to a ventilator, several steps should be taken, including the following:
    • Preparing the patient
    • Establishing an airway interface
    • Manually ventilating the patient
    • Stabilizing the patient's cardiovascular status
    • Meeting ventilation needs
    • Treating the cause of respiratory failure 
  66. Guidelines for neuromuscular disorders!
    • Full or partial support
    • NPV or PPV
    • Nonivasive or invasive ventilation
    • Assist/control mode
    • Volume control ventilation
    • Vt of 700 to 1000 L while maintaining the Pplateau at less than 30 cm H2O
    • F= 8 to 16 breaths/min
    • Inspiratory flow rates greater than 60 L/min
    • Flow waveform: constant or descending flow pattern
    • PEEP = 5 cm H2O
    • FiO2 = 0.21
  67. Indications for mechanical ventilation in acute exacerbation of asthma!
    • Exhaustion with developing metabolic acidosis and decresing pH
    • If aidible bilateral wheezes become distant as air trapping increases
    • Severe hypoxemia
    • Altered mental status changes
  68. Tidal volume and rate for patients with normal lungs?
    • High tidal volume to low to normal rate
    • Vt 10 to 12 mg/IBW
    • Rate 8-12
  69. Rate and tidal volume based on obstructive lungs (COPD)!
    • Moderate Tidal volume 8-10 mg/IBW
    • Rate 8-12
    • I:E ratio 1:4
  70. Rate and tidal volume based on restructive lungs (ARDs)!
    • Small tidal volumes 4-8 mg/IBW
    • maintain low alveoi pressure
    • Rate 15-25
    • Do not want auto PEEP with high rate decrease exhalation time
    • CO2 will rise
  71. A increase in gas flow, a decrease in I time and increase in PEEP pressure will...
    Decrease perfusion
  72. Slow or no flow will...
    Decrease PIP
  73. Decrease in PIP will...
    • Protect alveoli
    • Increase I time
  74. Better gas distrubtion
    Increase in mean airway pressure which improves oxygenation
  75. A decrease in E time will...
    • Increase chance for cardiovascular effects
    • Can lead to impression of inferior and vena cava which reduces venous return to heart
  76. Oxygen toxicity
    • destroys lung endothelium
    • Alveoli capillarily thickens
  77. CPAP only treats!
  78. BiPAP helps...
    Ventilation and perfusion
  79. Nuromuscular disorder
    • Normal drive to breath
    • Risk of aspiration
    • Weak muscles
    • Cant protect airway
    • Big tidal volumes at high flow
  80. Pulsus paradoxus
    • The strength of the pulses will change when inhaling
    • Change of PPl changes blood flow
  81. Asthma
    • High flow
    • Descending flow waveform
  82. Permissive hypercapnia
    Allowing CO2 to go up to prevent lung damage
  83. A increase in PEEP will...
    Increase ICP which is bad
  84. Iatrogenic Hyperventilation
    • Decrease in CO2 causes vasoconstruction of cerebral vessels which decreases ICP and swelling
    • CO2 25-30
    • Temporary
    • Effective for 48 hours
    • Controversial
  85. Refractory Hypoxemia
    Hypoxmia that does not respon to oxygen
  86. ARDS
    • Keep FiO2 low
    • Use PEEP higher to keep O2 low
    • Longer I time to improve oxygenation
    • make sure E time is long enought to prevent air trapping
Card Set
Respt 120
Test 2