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see also: Jet Anesthesia Adapter and Operating room setup for subglottic stenosis

return to: Laryngeal Surgery (Benign Disease) Protocols or Adult Airway in the Operating Room

note use of the blunt hollow metal adapter (Cadence (R) Part: 4400-12X2B 'custom hypo ndle 12 x 2 blunt tip') that is modified to permit placement in the side port of the Dedo Laryngoscopy. 

Note 'new' (as of July 2018) Jet Anesthesia unit depicted below:

Definition and Terms

1. Jet ventilation refers to delivery of oxygen via high pressure jet ventilator
2. Jet insufflation with passive expiration
3. During HFJV the ventilation gas is intermittently administered by an injector with a high frequency into the airway which is open to the outside. Exhalation occurs passively in the area nearby the wall of the airway cross-section. According to the availability of the technique and the indications jet ventilation can be implemented in an infraglottic, supraglottic, transtracheal or transluminal manner. To exert influence on gas exchange of the patient the respiratory rate, driving pressure, oxygen concentration and inspiration time can be changed according to the needs.

Indications

1. Direct laryngoscopy
2. Spontaneous ventilation, mechanical controlled ventilation, apneic intermittent ventilation
3. Transtracheal jet ventilation may be used even with partial airway obstruction.

Relative Contraindications

1. If a definitive airway can easily and rapidly be secured with endotracheal intubation
2. Significant direct damage to the cricoid cartilage or larynx
3. Complete upper airway obstruction
4. Airway obstruction below the vocal cords that renders exhalation difficult or impossible is a relative contraindication.
5. Foreign body which may be distally lodged
6. Severe tracheal stenosis, risk of excessive bleeding during the procedure, patients at risk for aspiration and exacerbation of lung diseases
7. Obesity or poor pulmonary compliance

Equipment

1. High-pressure non-collapsible oxygen tubing
2. Oxygen source with a flow at 10-15 L/min
3. Manual jet ventilator/insufflator device- hand held
4. Pressure regulator (less than 50 psi)

Preparation

1. Bed turned 90 degrees (Anesthesia on the right side of bed) prior to patient entering room.
2. Anesthesia induction agents dependent on anesthesiologist preference, age of patient and diagnosis requiring treatment.
3. Topical lidocaine often is used to minimize laryngeal sensitivity and to reduce the risk of laryngospasm
4. Ventilation is held briefly during tissue manipulation, debridement, or to avoid distal seeding, injury to normal tissues, or foreign object into the distal airway.
5. Routine moisturizing with atomized saline may prevent the excessive mucosal drying that may contribute to necrotizing tracheobronchitis (associated with jet >2 hours)

Technique

1. Components
   1. Injector needle- 13 gauge blunt ended stainless steel needle connected to toggle valve by 1.5 meter length high pressure tubing
      1. 16 gauge needle recommended for infant
   2. Toggle Valve- controls the delivery of the gas mixture, connected to accumulator by at least 3 meter length of high pressure tubing
   3. Accumulator- is the output of the regulator to allow for smoothing of jetting pressure, necessary for adults weighing over 100kg
   4. Mixer- oxygen (70%) and nitrous oxide (30%) are supplied from central sources at 50 psi and fed into mixer, flow restriction here
2. Injector needles is inserted into the right light channel of the laryngoscope (this should be tested prior to patient entering the room)
3. The fiberoptic light source is always placed in the light channel on the left side of the laryngoscope
4. The hypoxic patient should receive oxygen in intermittent bursts
   1. Adults: jet pressure starting at 20 psi, increased gradually until adequate chest rise and fall is noted, < 50 psi
   2. Children: jet pressure starting at 5-10 psi which is increased until adequate chest rise and fall is noted, <30 psi
   3. Rate: 20 bursts per minute.
   4. Insufflation should last approximately 1 second, and exhalation should be given 3-4 seconds.
   5. An adequate expiratory phase is important to minimize the risk of barotrauma.
   6. Hand-eye coordination of anesthesiologist is imperative (watching chest deflate, administering insufflation not a moment sooner)
5. Numerous variations have been used in microlaryngoscopy
   1. Structural modification of laryngoscope
   2. Percutaneous transtracheal jet catheter
   3. Nasotracheal jet catheter
   4. Carden tube
   5. Orotracheal jet catheter 
   6. Attachment of the jet injector into the lumen of the laryngoscope

Advantages

1. Enhances surgical exposure
2. Less direct mucosal trauma than endotracheal tube
3. Increased oxygen tension for laser cases

Disadvantages

1. Does not provide definitive airway protection against copious secretions or aspiration
2. Incomplete control of the airway
3. Use of subglottic ventilation (as per the Hunsaker catheter) ( Abdelmalak 2020) employs potentially flammable tubing that extends below the vocal cords and may not be laser safe with risk of airway fire- jet tubes extending into the subglottis may not all be considered laser safe 
   1. --Supraglottic jet anesthesia as described in this protocol does not include introduction of potentially flammable materials into the work area and therefore would be considered laser safe.
   2. --Use of supraglottic jet anesthesia during laser microdirect laryngoscopy has been extensively reported in peer-reviewed publications (Zeng 2021, Halmos 2020)
   3. --Specific comment regarding supraglottic jet anesthesia as described in this protocol as safe for laser use was addressed over 30 years ago by Gussack et al (Gussack 1987): "Since 1984, we have developed a technique utilizing jet ventilation delivered through a metal delivery system providing a relatively safe, ignition-free environment."
4. Requires specialized training required by all that use it and heightened communication between providers
5. Degree of gas exchange is unknown until end tidal capnography or ABG obtained, e.g. limited conditions for monitoring gas exchange and mechanics of ventilation in contrast to conventional ventilation
6. Complications
   1. Aspiration, GI insufflation, bleeding, pneumothorax, subcutaneous emphysema, catheter as foreign body and inadequate ventilation
   2.  Barotrauma: intrapulmonary trapping of air as evidenced by subcutaneous emphysema, pneumomediastinum, and pneumothorax
      1. Increased incidence with inadequate paralysis, laryngospasm, obstructing lesions etc.
      2. Transtracheal jet ventilation was associated with a significantly higher complication rate than transglottal jet ventilation (P < 0.0001; odds ratio, 4.3 [95% confidence interval, 1.9-10.0]). All severe complications were related to barotraumas resulting from airway outflow obstruction during jet ventilation, most often laryngospasms. (Jaquet et al)
7. Aerosol generation has been identified to occur employing jet anesthesia along with CO2 laser use - with a recent study (Zeng 2021) identifying that "Although direct laryngoscopy with GETA [general endotracheal anesthesia] was significantly associated with small increases in particle concentration, jet ventilation overall did not increase particle aerosolization." and "Nonetheless, judicious use of PPE [personal protective equipement] remains advisable during laryngology procedures."
   1. Azadeh Ranjbar et al (2021) interpreted this study by Zeng as having a sufficiently small sample size as to limit interpretation - and concluded that  "GETA [general endotracheal anesthesia] appears to be safest" in their focus on aerosol generation in the COVID pandemic era

Older Unit Depicted Below (retired from use July 2018)

References

Jaquet Y et al. Complications of different ventilation strategies in endoscopic laryngeal surgery: a 10-year review. Anesthesiology. 2006 Jan;104(1):52-9.

Merati AL et al. The utility of routine chest radiography following jet ventilation in elective laryngotracheal surgery. Laryngoscope. 2004 Aug;114(8):1399-402.

Evans KL, Keene MH, Bristow ASE. High-frequency jet ventilation: a review of its role in laryngology. J Laryngol Otol 1994;108:23--25.

Shikowitz MJ, Abramson AL, Liberatore L. Endolaryngeal jet ven- tilation: a 10-year review. Laryngoscope 1991;101:455--461.

Crockett DM, McCabe BF, Scamman FL, Lusk RP, Gray SD. Venturi jet ventilation for microlaryngoscopy: technique, complications, pitfalls. Laryngoscope 1987;97:1326--133

Chitilian HV, Bao X, Mathisen DJ, and Alfille PH: Anesthesia for Airway Surgery   Thoracic Surgery Clinics  2018 Volume 28, Issue 3, pages 249-255

Scamman FL and McCabe BF: Supraglottic Jet Ventilation for laser Surgery of the Larynx in Children  Ann. Otol. Rhinol. Laryngol., 95:142-145, 1986

Zheng M, Lui C, O'Dell K, M Johns M, Ference EH, Hur K. Aerosol Generation During Laryngology Procedures in the Operating Room. Laryngoscope. 2021 Dec;131(12):2759-2765. doi: 10.1002/lary.29729. Epub 2021 Jul 2. PMID: 34213770.

Abdelmalak BB, Doyle DJ. Recent trends in airway management. F1000Res. 2020 May 13;9:F1000 Faculty Rev-355. doi: 10.12688/f1000research.21914.1. PMID: 32489647; PMCID: PMC7222034.

Azadeh Ranjbar P, Al Omari AI, Mann D, Balouch B, Sataloff RT. COVID-19 and laryngological surgery. Oper Tech Otolayngol Head Neck Surg. 2022 Jun;33(2):84-95. doi: 10.1016/j.otot.2022.04.003. Epub 2022 Apr 28. PMID: 35502268; PMCID: PMC9045871.

Gussack GS, Evans RF, Tacchi EJ. Intravenous anesthesia and jet ventilation for laser microlaryngeal surgery. Ann Otol Rhinol Laryngol. 1987 Jan-Feb;96(1 Pt 1):29-33. doi: 10.1177/000348948709600107. PMID: 2880547.

Halmos GB, Plate CMA, Krenz G, Molenbuur B, Dikkers FG, van Dijk BAC, Wachters JE. Predictors for failure of supraglottic superimposed high-frequency jet ventilation during upper airway surgery in adult patients; a retrospective cohort study of 224 cases. Clin Otolaryngol. 2020 Mar;45(2):253-258. doi: 10.1111/coa.13465. Epub 2019 Dec 12. PMID: 31628712; PMCID: PMC7027582.