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Causes for decreased static compliance
  • Pneumothorax
  • Pneumonia
  • ARDS
  • Pleural Effusion
  • Pulmonary Edema
  • Fibrosis
Static Compliance Ranges

  • 35-50 cmH2O

  • May go as high as 100 cmH2O

Static Compliance Formula
Vt-[{Static pressure-Peep) x tubing compliance]
_______________________________________
          Static pressure-Peep
Corrected Vt formula
Vt - [{Static pressure-Peep) x TCF ]
To correct an inverse I:E ratio ______ Vt.
Decrease Vt which will increase expiratory time.
To correct an inverse I:E ratio ______ peak flow.
Increase peak flow which will increase expiratory time.
To correct an inverse I:E ratio ______ respiratory rate.
Decrease RR which will increase expiratory time.
Define PEEP
  • Positive End Expiratory Pressure
  • Airway pressure is not allowed to return to atmosphere at end exhalation
  • Increasing PEEP increases cardiovascular work
Physiologic effects of PEEP
  • Increased mean intrapulmonary pressure
  • Increased mean intrathoracic pressure
  • Increased FRC
  • Decreased WOB
  • Improved oxygenation (Increases PaO2)
Indications for PEEP
  • Pulmonary edema
  • ARDS
  • Chest trauma
  • Atelectasis
Alveolar minute ventilation
AMV = (Vt-Deadspace) x RR
Volume lost in tubing
(Static pressure-PEEP) x TCF
Flex Tubing Deadspace
Inches x 10ml/in =
Anatomical Deadspace
Weight (kg) x 2.2 lbs x 1ml =
If low pressure alarm sounds ________.
Check for leaks
If PaO2 low at 60% FiO2 next step is _________
Increase PEEP
Weaning Parameters
  • Vt  >5 ml/kg
  • VC  >15 ml/kg
  • RR  >6 <35 b/m
  • NIF  20 cmH2o or more
  • Minute Volume  <10 L/m
  • FIO2  <50%
  • VD/Vt  <.60
  • Cs  >25 ml/cmH2O
Define VC
  • Vital capacity
  • Total amount of air that can be exhaled after a maximum inspiration
Define Vd/Vt
  • Ratio of dead space to tidal volume
  • Normal range .2-.4
Hazards of PEEP
  • Decrease in cardiac output
  • Increase pulmonary shunting
  • Decreased lung compliance
  • May cause pulmonary barotrauma
Indications for CPAP
  • Same as for PEEP
  • Pt must be breathing spontaneously
Goal of CPAP Therapy
  • Improve hpoxemia
  • Decrease intrapulmonary shunting
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