Airway Management/Ventilation Flashcards
How to size an oropharyngeal or nasopharyngeal airway
Oropharyngeal airway - teeth to the angle of the mandible
Nasopharyngeal airway - measure from the nose to the tragus
–Remember the bevel always points to the turbinates
What to do if you screw up an intubation
Have a back up plan
-LMA or nasopharyngeal airway ready to go
Have someone else there to help
Have all equipment and back up that you need prepared before
Document trauma, consult appropriate specialists
What is a Combitube?
Used as a back up for failed intubation on a patient that is completely unconscious
Not considered a definitive airway
Inserted blindly and utilized for difficult airways
How do you select the appropriate size endotracheal tube
Only people that are using smaller than 5.0cm are children
Should place at least a 7.0
Adult female: 7.0-7.5
Adult Male: 8.0-9.0
Drugs used for rapid sequence intubation
Induction (sedation) agents:
Etomidate (most common) 20mg- can cause adrenal suppression
Ketamine
Fentanyl
Midazolam
Propofol - also very easy to use
Thiopental
Methohexital
Neuromuscular Blocking Agents:
Succinylcholine (most common) 120mg - problem is that it causes electolyte gradient shifts to occur - beware in hyperK or hx of malignant hyperthermia
Rocuronium
Vecuronium
Order of rapid sequence intubation
Plan
Preparation - drugs, your equipment and instruments
Protect the cervical spine
Positioning - patient’s head and your equipment to the right
Pre-oxygenate the patient
Pretreatment (adjunct medications - Zofran, Lidocaine for vagal response)
Paralysis and induction (other way around)
—-Administer sedation medication first (etomidate)
—-Administer neuromuscular blocking agent next (succ)
Placement and proof
–Colorimetric end-tidal CO2 detector, 5 point auscultation, mist in tube, CXR
Postintubation management
–Secure the tube, given continuous sedation
Volume Control Modes
Assist/Control
- requires the least amount of effort on the part of the patient
–breaths are given either according to the pre-set rate, or if the patient’s inspiratory effort is sensed by the ventilator
—-If the pt attempts to breathe on their own, they will still receive a full tidal volume
–Each breath is given at least to the pre-set tidal volume
–Danger is it can lead to hyperventilation if the patient starts to breathe too fast
SIMV - Synchronized Intermittent Mandatory Ventilation
–Not as often used
–Similar to A/C but it will allow the patient to take a smaller breath beyond the pre-set rate.
–SIMV constantly recalculates the minute volume every 7.5 seconds
–If it determines that the minute volume will not be reached because the breaths the patient is taking are too small, it will wait until it senses a breath and then it will deliver the appropriate breath at the pre-set tidal volume
Pressure Control Modes:
Pressure Controlled Ventilation
–All the same features of A/C but the ventilator delivers the breath over a pre-set inspiratory time until a pre-set peak inspiratory pressure (PIP) is reached, irrespective of tidal volume.
–So instead of volume being the thing that we are worried about, it is the pressure within the lung
PRVC - Pressure-Regulated Volume Control
–Similar to A/C but combines pressure-limited, volume-targeted, time cycled breaths. The PIP delivered by the ventilator is varied on a breath to breath basis to achieve a target tidal volume that set set by the user.
What is PEEP?
Positive end-expiratory pressure
Prevents against alveolar collapse, and applies a pressure to maintain the reserve volume
In normal people, alveolar collapse does not happen and they do not need to be held open and the end-expiratory pressure returns to 0cm H2O.
With an increase in PEEP, the pressure will continue to be elevated to keep alveoli open
Usually set to minimum of 5cm H2O
Problems if the PEEP is too high
Will cause increased dead space in the lungs because of the amount of air that is staying within the lung at the end of expiration
Increased amount of dead space decreases the amount of space available for ventilation
Will also create pressure build up on alveoli and this can cause barotrauma
If alveoli are kept open too long, can crease ARDS
When do you use volume assist control vs pressure assist control
In patients that cannot breathe - Pressure assist
—Blow the lungs open
—Good for restrictive or obstructive lung disease, PNA
In patients that won’t breath - volume
—Neurologic disorders, ingestion of respiratory depressants
—Lungs are just fine. The brain isn’t working. Need the volume
Initial settings for volume controlled A/C
vT: 6mL/kg of ideal body weight
f (rate): 14-18 breaths per minute - if very acidotic, you might want to increase minute volume to blow off CO2
FiO2: 100%
PEEP: 5-10cm H2O
—remember that the more opacification CXR, the PEEP will be required to prevent intrapulmonary shunting
—If hypoxia persists, increase it until the SaO2 reaches 88% but never exceed 20cm H2O
—After adjusting the PEEP, check the plateau pressure (that which is reached at the end of expiration), and if more than 30cmH2O, decrease the vT but don’t drop below 4mL/kg of ideal body weight
Initial settings for pressure control A/C
PEEP: 5-10cm H2O, depending on the degree of hypoxia
FiO2: 100%
Driving pressure not to exceed, 30cm H2O (driving pressure is the pressure that is given to reach the peak inspiratory pressure, which is the same as the plateau pressure in this mode)
f (rate): 14-18 bpm
Inspiratory time adjusted to the keep the I:E ration 1:1.5 or higher
—If hypoxia persists, increase the PEEP until the SaO2 reaches 88%, but remember that driving pressure is given on top of the PEEP, so an increase in the PEEP requires a decrease in the driving pressure to keep it less than 30cm H2O
What to do after the ventilator settings have been set
Check an ABG
Make changes to the rate to change the PaCO2 (increase f for a high PaCO2 and decrease for a low one) but leave the vT in the 4-6 range, keeping the plateau pressure or inspiratory pressure <30
Lower the FiO2 to keep the PaO2 between 55-70mmHg and the SaO2 between 88-94%
Trouble shooting the vent:
PaO2 too low?
PaCO2 too high (in volume control A/C)?
PaCO2 too high (in pressure control A/C)?
PaCO2 too low (in volume control)?
PaCO2 too low (in pressure control)?
PaO2 too low?
–Increase the PEEP, increase the FiO2
PaCO2 too high (in volume control A/C)?
—Increase rate, increase vT
PaCO2 too high (in pressure control A/C)?
–Increase driving pressure, increase rate
PaCO2 too low (in volume control)?
–Decrease rate, lower vT
PaCO2 too low (in pressure control)?
–Decrease rate, lower driving pressure
