Ventalation Flashcards
Breathing and decreasing ICP
Hyperventilation
MOA:
Hyperventilation–> ↓ PCO2 –> vasoconstriction –> ↓ cerebral blood flow–> ↓ ICP
Noninvasive ventilation
positive pressure ventilation through a noninvasive interface: nasal mask, facemask, or nasal plugs
vs.
invasive interface (endotracheal tube, tracheostomy)
Criteria for Extubation from Mechanical Ventilation-
Spontaneous respiratory rate
< 33 breaths/min
Initial settings for Noninvasive ventilation
FiO2, Ins/ Expiratory pressure
FiO2 100%
Inspiratory= 8
Experitory= 4
titrate by 2
Criteria for Extubation from Mechanical Ventilation-
A-a gradient
< 300-500 mm Hg
Assist Control
ventilator delivers preset breaths in coordination with the respiratory effort of the patient
The RR set is the RR they get
Spontaneous breathing independent of the ventilator between A/C breaths is NOT allowed.
Criteria for Extubation from Mechanical Ventilation-
Po2 (on 40% Fio,) and Pco2
Po2 (on 40% Fio,) > 70 mm Hg
Pco2 < 45 mm Hg
Pressure support ventilation
Every time a pt initiates a breath, they get the pressure I set
Synchronous intermittent mandatory ventilation
Ventilator delivers preset breaths in coordination with the respiratory effort of the patient.
Spontaneous breathing is allowed between breaths
frequently the Ventilation mode of choice in patients whose respiratory failure is not severe and who have an adequate respiratory drive.
Pressure support ventilation
A respiratory rate (RR) of _________ breaths per minute is recommended for patients not requiring hyperventilation
8-12
FiO2 settings
The lowest FiO2 that produces:
Arterial oxygen saturation (SaO2) > 90%
PaO2> 60 mm Hg .
Determining Tidal Volume
Initial TV ~ 6 mL/kg of ideal body weight
goal is to adjust the TV so that plateau pressures are less than 35 cm H2O.
Plateau= no flow in ventilatory, measuring pressure in alveolus (measuring pulm compliance)
Minute Ventilation
Total volume of gas entering lungs per minute (VE)
VE = VT × RR
VT = 500 mL/breath
Primary variables that regulate PaO2
FiO2
PEEP- Better choice
A ↓ in PAo2 causes a ___________ (in CV system)
hypoxic vasoconstriction
shifts blood away from poorly ventilated regions of lung to well-ventilated regions of lung.
Changes in Peak Pressure
Suggests airway problem
- Change in PEEP
- Change in airway resistance (mucous plug, vent kink, bronchospasm)
-Change in compliance (plateau)
Quick changes in plateau pressures (aka lung compliance)
- Pulm Edema
- Pneumothorax
- Pleural Effusions
- Abdominal Compartment syndrome
lung compliance
change in lung volume for a change in pressure
( ΔV/ ΔP)
inversely proportional to wall stiffness.
High compliance = lung easier to fill
lower compliance = lung harder to fill.
Pathology and changes in lung compliance
↑ in pulmonary fibrosis, pneumonia, pulmonary edema;
↓ in emphysema, normal
aging.
lung compliance equation
= ΔV/ ΔP
Changes in Peak Pressure from change in airway resistance can be from?
mucous plug
vent tube kink
bronchospasm
airway resistance is on vent is shown as?
Peak Pressure
Auto - PEEP physiology
Feels like breathing on top of a breath
Incomplete expiration prior to the initiation of the next breath causes progressive air trapping (hyperinflation).
With each inspiratory effort, the ventilator delivers a full assisted tidal volume.
Assist-control ventilation
Consequences of high plateau pressure
bara-trauma
ARDS and the vent
Low tidal volume
increase peep
COPD and vents
problems and solutions
↑ airway resistance (give bronchodilator)
non-adequate time for expiration ( decrease the RR or shorten inspiratory time)
