CCT Vent Mgt

To maintain alveolar Gas exchange appropriate for the patients metabolic needs and to correct hypoxia and/or hypercapnia.

• – Volume of each delivered breath
• – How is it calculated?
• • 7-10 ml/kg of “ideal body weight”
• • Overweight people do not have bigger lungs

• – Fraction of inspired concentration of
• oxygen
• • Ranges from 21% to 100%
• • Initially set the FiO2 at 100% and titrate down based on blood gas values
• • Once blood gases have been obtained it is possible to titrate the FiO2

• – Number of breaths per minute
• – Depends on what is wrong with the patient
• – Initially set at 12-14 (adult) breaths per minute but can be higher or lower
• – Rate must be matched with the Vt to ensure adequate minute volume

• – Function of tidal volume and respiratory rate and is normally 6-10 liters in an adult
• – Represented by the following formula:
• • Vm (L/min) = Vt (ml) X respiratory rate (BPM).

• – Assist Control-AC
• – Synchronized intermittent mandatory ventilation-SIMV
• – Continuous Positive Airway Pressure- CPAP
• – Bilevel Positive Airway Pressure- BiPAP

• – Provides full Vt at a minimum preset rate
• – Patient can initiate breaths in this mode, providing additional full Vt
• – Provides near complete resting of the ventilatory muscles
• – Patient can be awake, sedated or paralyzed
• – Pressure support can not be initiated in this mode
• • Since patients can initiate ventilation, they can hyperventilate and become alkalotic. They can also “stack” breaths which can result in air-trapping and the possibility of barotrauma. May want to consider sedation/paralysis to facilitate more effective ventilations

• – Delivers a fixed Vt at a preset rate but allows patient to take their own breaths.
• – When ventilator breath is delivered, ventilator will deliver set Vt.
• – Patient initiated breaths are totally dependant on
• patient.
• – Advantages-patients are more comfortable since they have more control over ventilations
• – Can result in respiratory fatigue if the rate is set too low causing a rise in pCO2 and air trapping i.e.: stacking breaths or auto PEEP.

• • In this mode you can only have the components of:
• – FiO2
• – PEEP
• – Pressure Support
• • No set rate or Vt.
• • Cannot give neuromuscular blockers to patients in CPAP
• • Use sedation conservatively and with extreme caution
• – Generally used for weaning and mode used prior to
• extubation.

• • Ventilators can be set to provide a fixed airway pressure at the end of expiration
• • Opens closed alveolar units increasing lung area for gas exchange.
• • PEEP can improve secretion drainage from closed alveoli
• • Typical PEEP settings are from 5-10 but can go over 20
• – PEEP can reduce venous return and lower left ventricular afterload; PEEP especially at high pressures can cause barotrauma

• • “Turbo Boost” added to each Patient Initiated breath to help overcome the resistance of the Vent circuit and airway device
• • Patient triggers the ventilator at a predetermined pressure during inspiration (sensitivity), ventilation is terminated when the patient ceases to inspire
• • Patient has full control over his ventilatory pattern and minute volume
• • Cannot be used in heavily sedated, paralyzed or comatose patients

• • Amount of inspiratory effort required to initiate an assisted breath – Ranges from 1-8 L/min.
• – 1 L/min. is the most sensitive meaning it is the most sensitive to the patient initiation of a breath which decreases their work of breathing
• – If the sensitivity is turned off that means the ventilator is in full control mode-The patient cannot initiate a breath on their own
• • This is very uncomfortable and frightening for the patient unless they are sedated and paralyzed

• – Can be adjusted so that the inspiratory volume can be delivered in time to allow for adequate exhalation.
• – Dependant on Vt, and Rate.
• – Most commonly used rates are 40-80 lpm
• • How quickly the breath is delivered
• – If rate is set at 20 lpm the breath will be delivered slowly
• – If the rate is set at 100 the breath will be delivered quickly

• Inspiration/Expiration Ratio
• – Normal starting I/E ratio is 1:2
• • It generally takes the average person to inspire in 1 second and expire in 2 seconds
• – If the patient has an obstructive airway disease (COPD) then consider reducing to 1:3 or 1:4 to prevent air trapping
• – Use Peak Flow to obtain adequate I:E.

• • Displacement
• • Obstruction
• • Pneumothorax
• • Equipment Failure
• – If equipment failure is suspected the patient should be removed from the ventilator and manually bagged

• • Two things can change CO2
• – Respiratory rate
• – Vt
• • Change only 1 setting at a time
• • If you have calculated the Vt correctly, adjust the rate
• • If rate changes seem inappropriate, change Vt first

• • Two things can change oxygenation levels
• FiO2
• PEEP

• • Consider increasing their respiratory rate
• • Consider increasing Vt.
• • Can result in respiratory acidosis
• •We want to Increase Minute Volume

• • Consider decreasing their respiratory rate
• • Consider decreasing Vt
• • Can result in respiratory alkalosis
• • Decrease Minute Volume

• • Adult 12-14 BPM
• • Increase will increase Vm, and Decrease ETCO2
• • Decrease will Decrease Vm, and Increase ETCO2

• 7-10 ml/Kg
• Increase will increase Vm, and Decrease ETCO2
• Decrease will decrease Vm, and Increase ETCO2
• (Vm=Minute Volume)

• • CPAP-Continuous Positive Airway Pressure
• – CPAP = PEEP
• • BiPAP-Bilevel Positive Airway Pressure
• – BiPAP = Two levels of (PS) PEEP + PS
• • IPAP = Inspiratory PAP (PS)
• • EPAP = Expiratory PAP (PEEP)

• • “Normal” ETCO2 is 35 – 45
• • “If V/Q are on equal terms, ETCO2 and PACO2 should be close to equal”

• • There are 4 Questions to use every time you monitor Waveforms.
• – Is there rise and fall of the waveform?
• –What is the number Value and is it “Normal”?
• –What is the shape of the Waveform?
• – Does it return to baseline?

• – Frequency
• A waveform should be present for every exhalation
• Presence of a waveform = presence of carbon dioxide
• – Height
• Hypermetabolic states will increase the height of the capnogram as will prolonged hypoventilation
• Decreases in cardiac output will decrease the height of the capnogram as will hyperventilation
• – Baseline
• Gradual elevations in Phase 0 or Phase I indicate re-breathing
• A sudden rise in EtCO2 AND the baseline is likely indicative of sample contamination
• – Shape
• Deviations from the normal curve of the waveform have specific meanings
• All humans with healthy lungs have the same shaped waveform
• • Any variation warrants an evaluation of the cause
• – Things to assess
• • Expiratory upstroke
• – Steep, sloping, prolonged
• • Alveolar plateau
• – Flat, prolonged, deflection, slope
• • Inspiratory downstroke
• – Steep, sloping or prolonged
• –Whenever possible, compare the EtCO2 with the measured PaCO2on the ABG.

• – ET Tube becomes Displaced
• – ET Tube is Plugged or Kinked
• – Cardiac Arrest
• – Apnea or Mechanical Ventilator Failure
• – Equipment Malfunction