Jet ventilation is a form of mechanical ventilation that uses very high respiratory rates and small tidal volumes delivered via a jet of gas. It can be used supraglottically or subglottically for procedures involving the airway. Key indications are subglottic and tracheal stenosis. The jet ventilator provides active insufflation of gas while exhalation is passive. Gas exchange occurs via mechanisms like laminar flow and Taylor dispersion. Precautions must be taken to ensure adequate ventilation and monitoring of end-tidal CO2. Complications can include barotrauma, pneumothorax, or difficulty ventilating.

1. Jet ventilation in the operating
room
HELGA KOMEN, MD
DEPARTMENT OF ANESTHESIOLOGY, WASHINGTON UNIVERSITY IN ST LOUIS

2. Jet ventilation - definition
◦ High frequency jet ventilation (HFJV) is a form of mechanical ventilation that
combines very high respiratory rates (>60 breaths per minute, i.e. > 1 Hz (1 Hz = 1 cycle/sec.))
with tidal volumes that are smaller than the volume of total dead space, anatomic +
equipment (<1mL/kg), using a jet of gas [Standiford TJ et al. Chest 1989.].
◦ That is what we use in the OR
◦ First described by Klain and Smith!
◦ Klain M, Smith RB: High frequency percutaneous transtracheal jet ventilation. Crit Care Med 1977;
5: 280-7
JET VENTILATION IN THE OPERATING ROOM

3. Jet ventilation – available only in Europe (not FDA approved!)
◦ Superimposed jet ventilation (SHFJV®) - jet ventilation of normal frequency (<1Hz)
and high frequency (>1Hz) conducted simultaneously, permits ventilation at two different
pressure plateaus. Thus, oxygenation as well as CO2 elimination can be regulated efficiently.
(e.g. Twinstream™).
◦ We don`t have it
◦ This technique cannot be applied through an infraglottic or transtracheal catheter.
◦ First described in 1990s
◦ Aloy A, Schachner M, Spiss CK, Cancura W: [Tube-free translaryngeal superposed jet ventilation].
Anaesthesist 1990; 39: 493-8 26.
◦ Kull M, Samarütel J, Nurm V: Double frequency jet ventilation for endolaryngeal laser surgery. Lasers
in medical science 1993; 8: 141- 146
JET VENTILATION IN THE OPERATING ROOM

4. HFJV (Supraglottic/Subglottic) -Indications
• Subglottic stenosis
• Tracheal stenosis
• Glottic stenosis
JET VENTILATION IN THE OPERATING ROOM

5. HFJV, supraglottic - principles
JET VENTILATION IN THE OPERATING ROOM

6. HFJV, subglottic - principles
JET VENTILATION IN THE OPERATING ROOM

7. HFJV - principles
-The insufflation of gas through the jet nozzle is an active process, whereas
the exhalation happens outside the jet nozzle and is passive (picture!)
- Tidal volumes utilized are smaller than the total dead space (anatomical +
equipment), therefore gas exchange must occur via *alternative means (next
slide!) in addition to the standard bulk flow (convective) ventilation that occurs
during a normal inspiratory-expiratory cycle.
- Expired gas flows out passively during HFJV, seeking its path of least resistance in
the annular or “unused” spaces around the highly accelerated inspired gas. By
moving out along the airway walls, expired gas facilitates mucociliary clearance.
JET VENTILATION IN THE OPERATING ROOM

8. *Alternative means of gas exchange:
•Laminar flow (non-turbulent, low Reynolds number) in small airways produces a scenario where the high-
pressure of the delivered breath flows down the middle of the airway and the margins of the airway contain gas
moving in the opposite direction.
•The Pedulluft effect describes the movement of inspired gas from those alveoli that fill the fastest to those that
are slower to fill. This is based on the fact that there is variability between alveoli in both resistance and
compliance.
•Taylor dispersion (convective streaming) is the diffusion of the high velocity central gases to the margins of the
airway. This phenomenon primarily occurs in the smaller airways and further enhances gas mixing and hence
exchange.
•Cardiogenic mixing also contributes to gas exchange during jet ventilation, albeit likely to a lesser extent than
those mentioned previously. It occurs as a result of the rhythmic, pulsatile nature of the heart conferring a mixing
of gases
- It is important to maintain an adequate portion of the upper airway open to the atmosphere, to allow exhalation
and thus avoiding overdistention of the distal airways (inadvertent PEEP increases).
JET VENTILATION IN THE OPERATING ROOM
HFJV - principles

9. (Relative) Contraindications for HFJV
- Airway stenosis >50% preventing air egress of gas following insufflation - no catheter should be
introduced through an airway narrowing when the remaining cross section for exhalation is less
than 50% of normal. Supraglottic jet ventilation advised!
- Morbid obesity preventing ventilation with patient relaxed (airway collapse, difficulty
visualizing chest rise and fall)
JET VENTILATION IN THE OPERATING ROOM

10. Picture of jet vent machine (take it!)
JET VENTILATION IN THE OPERATING ROOM

11. HFJV in the operating room - equipment
- Monsoon jet ventilator (POD5 (East pavillion supply room)
one and POD3 one)
- CO2 transcutaneous monitor
- Rigid laryngoscope (inserted by surgeon)
- Jet cannula
JET VENTILATION IN THE OPERATING ROOM

12. - Supraglottic
jet cannula
- Subglottic - Hunsaker tube, LaserJet catheter
HFJV in the operating room - delivery
JET VENTILATION IN THE OPERATING ROOM

13. -Make sure patient received good preoxygenation
-All the equipment (surgeon, jet vent) has to be ready/checked before induction
-After induction of anesthesia (fentanil/propofol/succinylcholine) direct laryngoscopy is
performed by the surgeon. Jet cannula is attached to the rigid laryngoscope
-Jet Ventilation is started
- typical settings – driving pressure (DP) 20-30 psi, frequency (f) 120/cpm, FjetO2 100%
- Make sure you see “rise and fall” of the chest wall (smaller amplitude than during ventilation
through OT tube)
- If laser is used, press option `laser` on jet ventilator (lowers FjetO2 to 30%)
JET VENTILATION IN THE OPERATING ROOM
HFJV - Induction of Anestheshia

14. HFJV - Maintenance of Anesthesia
- TIVA – remifentanil + propofol infusion
- Transcutaneous CO2 monitoring - PtcCO2
• latency period of approximately 1 minute
• transcutaneous measurement is local only (it does not represent a global value of the whole organism,
but it yields a fair trend of the global CO2 course)
• an increase of PaCO2 to the extent of 1.5 times baseline can be tolerated at the end of surgery
• If PtcCO2 high, try increasing DP (max 40psi)
-BIS monitoring- preferable
-Muscle relaxation – usually, procedure is one hour long. You may choose to use rocuronium
(Sugammadex?!)
JET VENTILATION IN THE OPERATING ROOM

15. - HFJV does NOT allow: setting specific tidal volume, sampling EtCO2
Inspiratory time (IT)%: 35% (about 1/3 of the respiratory cycle)
DP: 20-40 psi (pound-force per square inch)
f: 120/cpm (above 100/cpm ventilator safety features work best)
Humidifier: As Needed (not required for cases <30mins, in ICU mandatory due to prolonged
ventilation), <50% humidity
PP: 24 cmH2O (may increase as needed – consider as mean airway pressure; measure through
same port/tube used for jet ventilation (BLUE line))
PIP: 28 cmH2O (measured through separate port/tube than used for jet ventilation (RED line),
e.g. when we use Hunsaker tube it can be attached to side port)
Laser FiO2% = 30%
-IT and f improve oxygenation (by increasing "auto-PEEP" or pause pressure), while an increase
in DP and a decrease in f, improve ventilation (CO2 exchange).
Jet ventilator settings
JET VENTILATION IN THE OPERATING ROOM

16. • Optimum frequency for the broadest range of lung pathologies (approx. 90 – 93%) ranges between f =
110 – 140/cpm in patients weighing more than 12 kg.
• The lowest peak pressure in airways with a tolerable inadvertent PEEP occurs at a frequency of 120
c/min.
• Pawmax increases at frequencies under 100 c/min and inadvertent PEEP increases at frequencies over
150 c/min.
• For this reason the recommended golden standard is a frequency of = 120 cpm.
• An increase in DP results in higher TV and MV; however, this relationship is not linear
because of the complex interaction of multiple factors.
Jet ventilator settings – frequency
JET VENTILATION IN THE OPERATING ROOM

17. -Difficulty ventilating
-CO2 retention (transcutaneous monitoring available!) - Degree of gas exchange is uknown until
end tital capnography or ABG obtained, i.e. limited conditions for monitoring gas exchange and
mechanics of ventilation in contrast to conventional ventilation
-Hypoxia
-Barotrauma - observation of chest rising during inspiratory phase and falling during expiratory
phase remains the main safety feature to prevent BAROTRAUMA.
- Pneumothorax
- Mediastinal emphysema, Subcutaneous emphysema (more frequent with transtracheal ventilation )
-Gastric distension
-Distal seeding of virus if used for papilloma surgery (N95 mask mandatory)
JET VENTILATION IN THE OPERATING ROOM
Jet ventilation complications
- postoperative CXR indicated after each case!

18. Manual jet ventilation
• Emergency ventilation situations – post-cricothyrotomy trans-tracheal ventilation
• Equipment
• High-pressure non-collapsible oxygen tubing
• Oxygen source with a flow at 10-15 L/min or higher
• Manual jet ventilator/insufflator device - hand held
• Pressure regulator (less than 50 psi)
- Start with low-frequency JV with approximately 20 cpm, DP 10psi
Increase DP by 5 psi at a time if SpO2 not satisfying.
- We have 3 Manual jet ventilators on POD5 (two in airway carts between ORs
218 and 219, and one in the supply room West pavillion)
JET VENTILATION IN THE OPERATING ROOM

19. Thank you!
JET VENTILATION IN THE OPERATING ROOM