Mechanical Ventilation Flashcards
Pressur control
Predetermined pressure delivered at given interval
Advantages of positive pressure ventilation
Patients can’t cough -> atelectasis
- happens within minutes -> incidence of pneumonia increases with each day intubated
PEEP, suctioning, and alveolar recruitment counteract atelectasis
Extubate as soon as possible
Indications for capnography
Detect esophageal intubation, ventilation machine problems
Det ct hyperventilation, high/low metabolic rates
Detect PE, bronchospasm, calculate dead space
Dead space equation
Vd/Vt = [(PaCO2 - PetCO2)/PaCO2)]
Normal=0.3
Administering O2
Nasal cannula 0-7 L -> can detect ETCO2
Masks 10+ L -> can’t detect ETCO2
Oxygen tent 10-15 L -> can detect ETCO2
Strategies to prevent trauma
Volutrauma more injurious to lungs than barotrauma
- give smaller tidal volumes at greater RR
- higher PaCO2 allowed
Specific settings on ventilator
TV of 6 mL/kg -> prevents volumtrauma
Plateau pressure 6-10 cm H2O
FiO2
+ PEEP Resp
Improves hypoxemia
Opens airway, improves FRC
Prevents derecruitment and atelectasis
Allows lower FiO2
(-) PEEP Resp
Barotrauma, PTX
Worsen V/Q mismatch
Increase dead space ventilation
+ PEEP CV
Improves O2 delivery to myocardium
Decreases LV afterload
Treats OSA
(-) PEEP CV
Decreases preload and venous return
Increases CVP
Increases RV afterload
Worsens hypotension in hypovolemia
+ PEEP CNS
O2 delivery improved
Treats OSA
(-) PEEP CNS
Increases intracranial pressure
Decreases cerebral perfusion pressure
Increased risk of embolization
+ PEEP liver and kidney
Decreases renal and hepatic blood flow
(-) PEEP liver and kidney
Increases ADH secretion
