Measuring tracheal airway pressures during transtracheal jet ventilation: an observational study*

Application and Technical Principles of Catheter High-Frequency Jet Ventilation

The aim of this publication is to analyze the topic of high-frequency jet ventilation (HFJV), namely catheter HFJV (C-HFJV), from a mathematical-physical as well as a clinical point of view. There are known issues with applying anesthesia and artificial lung ventilation (ALV) during surgical procedures in the upper airways, e.g., during bronchoscopy or tracheostomy. The principles, advantages, and disadvantages of HFJV are discussed in context with basic physical principles to clarify the proper use of this method. The basic technical principles of catheter construction, as well as its functional properties from a biophysical point of view, are introduced. Also, the placement of the catheter in the airways, the set-up of the HFJV ventilator, and the indications as well as the risks and contraindications of the use of C-HFJV are analyzed. This leads to the explanation of potentially optimal techniques for C-HFJV applications. In this article, we present the positive effects of C-HFJV even with complications such as bacterial or viral pneumonia, including COVID-19. In conclusion, we offer recommendations for clinical practice obtained from a literature review and from our rich clinical experience.

The efficacy of spontaneous and controlled ventilation with various cricothyrotomy devices: a quantitative in vitro assessment in a model lung

BACKGROUND

Guidelines for the management of a difficult airway recommend performing a cricothyrotomy in a "can't intubate/can't ventilate" situation. We investigated the tidal volumes delivered by controlled and spontaneous ventilation by seven commercially available cricothyrotomy sets (cuffed: Quicktrach II, Portex Cricothyroidotomy Kit, and Melker cuffed cannula and uncuffed: Airfree, 4.0-mm ID Quicktrach, 6.0-mm inner diameter Melker, and 13-gauge Ravussin cannula) and two improvised devices (14-gauge intravenous cannula and spike and drip chamber device).

METHODS

A LS800 model lung, set at different values for compliance and resistance and modified with different upper airway diameter, was ventilated via the respective cricothyrotomy device mechanically and using a self-inflating bag. With the 13-gauge Ravussin cannula and the 14-gauge intravenous cannula, a Manujet injector was used for jet ventilation. Spontaneous ventilation was simulated with a Michigan 560i lung.

RESULTS

During controlled or manual ventilation, all cuffed cricothyrotomy devices yielded adequate tidal volumes. Uncuffed devices provided tidal volumes≥300 mL only with an upper airway diameter of ≤3 mm. With a Manujet injector, adequate tidal volumes required an upper airway diameter between 3 mm and 5 mm. A spike and drip chamber device does not provide suitable emergency airway access. Spontaneous ventilation at adequate inspiratory pressure levels required a device inner diameter of at least 4 mm.

CONCLUSION

As expected, cuffed cricothyrotomy devices yield the best results during controlled, manual, and spontaneous ventilation. With uncuffed cricothyrotomy devices, ventilation becomes ineffective when the upper airway obstruction allows for an upper airway diameter>3 mm.

A complication of transtracheal jet ventilation and use of the Aintree intubation catheter during airway resuscitation

We report the management of a patient requiring surgical laryngoscopy with a view to laser resection of an epiglottic recurrence of laryngeal cancer. Previous attempts at tracheal intubation and awake nasal fibreoptic intubation had failed. During a previous anaesthetic the patient had been both 'impossible to intubate and to ventilate'. Neck scarring potentially complicated access for transtracheal jet ventilation. Nevertheless, a cricothyroid catheter was placed and surgery performed during low frequency 'volume' jet ventilation. Upper airway obstruction developed during the procedure, preventing exhalation, which led to raised intrathoracic pressure, cardiovascular collapse and barotrauma. The airway was re-established by insertion of an LMA Proseal. Fibreoptic placement of an Aintree intubation catheter through this allowed re-oxygenation and exchange for a cuffed tracheal tube. Some hours after the procedure, re-intubation was necessary. This was achieved using the Aintree intubation catheter as an aid to nasal fibreoptic intubation and as a tube exchanger. Novel roles of the Aintree intubation catheter and LMA Proseal in this case are discussed. Complications of transtracheal jet ventilation as well as possible methods for avoiding them are also reviewed.

[Bilateral tension pneumothorax after retrieval of transtracheal jet ventilation catheter]

We report a bilateral tension pneumothorax which occurred in a 36-year-old man after high-frequency jet ventilation (HFJV) for panendoscopy. The patient had been treated with radiotherapy and chemotherapy two years ago for an oropharyngeal adenocarcinoma, and by surgery for a recurrence. The incident occurred after a cough episode triggered by the withdrawal of the Ravussin transtracheal catheter. We are discussing the risk factors and the mechanisms of pneumothorax during HFJV with special emphasis on trapping and lung fibrosis.