Mechanical ventilation provides controlled, even breaths to patients who require assistance breathing. It acts as an extra set of lungs, allowing for long transports or complex medical situations. Key terms include tidal volume, respiratory rate, fraction of inspired oxygen, and positive end-expiratory pressure. Ventilators move air in and out of the lungs, facilitating gas exchange of oxygen and carbon dioxide in the alveoli. Settings are individualized but generally start at a tidal volume of 6-8 cc/kg, respiratory rate of 12, and PEEP of 5 cm H2O. Alarms alert to high or low pressures that could indicate issues like tube dislodgement or pneumothorax.

1. Mechanical Ventilation
101
“Tell me what I need to know, and not a syllable more.”
Edward D. Struzinski,
RN, CEN, CCRN, CFRN, NR/CCEMT-P

2. First: why should I bother using a
Vent?
 Medical situations?
 “A spare set of hands” dedicated to the Patient’s
airway.
 Provides constant, uninterrupted (generally),
controlled and equal breaths over a set
amount of time and volume or pressure.
 Transport distance.
 Can you manually use your BVM like that?

3. Terminology: know it, use it.
 The tubing connecting the Vent to the Patient is
called the circuit.
 The respiratory rate is called the frequency,
abbreviated as “f”.
 The amount of air given in a single breath is called
the tidal volume, abbreviated as “V(t)”.
 The amount of air given over a minute is called
minute volume, abbreviated as “V(e)”. It consists of
both Alveoli air and Dead Space air.

4.  The amount of Oxygen being given is called the
Fraction of Inspired Oxygen, abbreviated as
“FiO2” and properly written as a decimal. (ie:
40% Oxygen = 0.4 FiO2)
 The air in the entire airway not at the Alveoli
level is called Dead Space, because it does not
perform any gas exchange.
“He’s dead, Jim.”

5. Gas Exchange
Unlike dead space, the air within the Alveoli level IS
performing gas exchange.
Oxygen crosses into the bloodstream so that it can be taken
to the heart and oxygenate cells. This is Oxygenation.
Carbon Dioxide crosses from the bloodstream so that it can
be ventilated out of the body. This is Ventilation.
Sole, Lamborn, & Hartshorn. (2001). Critical Care Nursing.
“I pick things up … … and put them down.”

6. Air in … Air out
 All ventilators do the same job: They move air in.
They move air out.
 A bag-valve-mask is nothing more than a
MANUAL mechanical ventilator.
 A bag-valve-mask, however, cannot provide
exact timing, depth, or pressure. It is only as
good as the operator. We are predictably
unpredictable.

7. CPAP / PEEP
 CPAP is Continuous Positive Airway Pressure. It is an
airway procedure performed from the outside of the
body, using a well-sealed mask.
 PEEP is Positive End-Exhalation Pressure. It is an airway
pressure that occurs inside the lungs when the Patient is
intubated.
 CPAP and PEEP are synonymous to each other
because they are both designed to achieve the same
thing:
 mechanically keeping the Alveoli slightly-inflated under
a constant pressure. This better improves
Oxygenation.
 Both can cause significant Barotrauma.
 PEEP occurs normally all the time. Do you ever really
exhale ALL THE AIR in your lungs? This is termed
“physiologic PEEP”

8. Ventilator Settings
Individualized. What is the goal?
Patient’s ideal body weight. (Height & Gender).
Special considerations.
General settings:
FiO2 = 0.4 (40% Oxygen)
V(t) = 6 – 8 cc/kg
f = 12
PEEP = 5

9. Alarms
 The Vent will alarm when pressures reaching
the Patient are too High or too Low.
 Follow the Circuit, from the Patient to the
Ventilator.
 DOPE
 Dislodgement of the tube.
 Obstruction of the tube.
 Pneumothorax.
 Equipment failure.

10. References
 Society of Critical Care Medicine. (2007).
Fundamental critical care support, 4th ed.
 Sole, M., Lamborn, M., & Hartshorn, J. (2001).
Introduction to critical care nursing, 3rd ed.
 Solheim, J. (2014). Certified emergency nurse
review.
 Walls, R., Murphy, M. (2008). Manual of
emergency airway management, 3rd ed.