Manual translaryngeal jet ventilation and the risk of aspiration in a canine model

Supraglottic jet oxygenation and ventilation via nasopharyngeal airway for a patient with iatrogenic tracheoesophageal fistula: A case report

Background

Iatrogenic tracheoesophageal fistula (TEF) is a rare but life-threatening condition. No consensus has been reached regarding TEF treatment, though, stenting has been gaining popularity for less invasiveness than thoracic surgery. The airway management during stent placement for TEF could be challenging.

Case presentations

We report a patient who suffered from TEF after cardiac surgery with symptoms of persistent coughing and aspiration. He who was admitted for stent placement but ended up in failure and referred to our institution for further treatment. We successfully took advantage of the supraglottic jet oxygenation and ventilation (SJOV) during stent placement.

Conclusion

This is the first case so far describing SJOV in complicated stenting treatment. This demonstrates that SJOV can be applied for stent placement in TEF patients with restricted airways.

Dual-wavelength fiber-optic technique to assist needle cricothyroidotomy

The traditional needle cricothyroidotomy procedure is performed blindly without any medical equipment. Complications including posterior tracheal wall perforation, accidental vessel puncture, and missed tracheal puncture are reported. Therefore, we proposed a dual-wavelength fiber-optic technique based on the technique of near-infrared spectroscopy to assist operators performing needle cricothyroidotomy in a swine model. We embedded optical fibers in a 16-gauge intravenous needle catheter. Real-time data were displayed on an oscilloscope, and we used the program to analyze the data immediately. The change of optical density corresponding to 690-nm and 850-nm wavelengths and hemoglobin parameters (HbO₂ and Hb concentrations) was analyzed immediately using the program in the laptop. Unique and significant optical differences were presented in this experiment. We could easily identify every different tissue by the change of optical density corresponding to 690-nm and 850-nm wavelengths and hemoglobin parameters (HbO₂ and Hb concentrations). Statistical method (Kruskal-Wallis H test) was used to compare differences in tissues at each time-point, respectively. The p values in every tissue in optical density change corresponding to 690 nm and 850 nm were all < 0.001. Furthermore, the p values in every tissue in Hb and HbO₂ were also all < 0.001. The results were statistically significant. This is the first and novel study to introduce a dual-wavelength embedded fibers into a standard cricothyroidotomy needle. This proposed system might be helpful to provide us real-time information of the advanced needle tip to decrease possible complications.

Percutaneous Transtracheal Ventilation: Resuscitation Bags Do Not Provide Adequate Ventilation

Introduction:

Percutaneous, transtracheal jet ventilation (percutaneous transtracheal jet ventilation) is an effective way to ventilate both adults and children. However, some authors suggest that a resuscitation bag can be utilized to ventilate through a cannula placed into the trachea.

Hypothesis:

Percutaneous transtracheal ventilation (percutaneous transtracheal ventilation) through a 14-gauge catheter is ineffective when attempted using a resuscitation bag.

Methods:

Eight insufflation methods were studied. A 14-gauge intravenous catheter was attached to an adult resuscitation bag, a pediatric resuscitation bag, wall-source (wall) oxygen, portable-tank oxygen with a regulator, and a jet ventilator (JV) at two flow rates. The resuscitation bags were connected to the 14-gauge catheter using a 7 mm adult endotracheal tube adaptor connected to a 3 cc syringe barrel. The wall and tank oxygen were connected to he 14-gauge catheter using a three-way stopcock. The wall oxygen was tested with the regulator set at 15 liters per minute (LPM) and with the regulator wide open. The tank was tested with the regulator set at 15 and 25 LPM. The JV was connected directly to the 14-gauge catheter using JV tubing supplied by the manufacturer. Flow was measured using an Ohmeda 5420 Volume Monitor. A total of 30 measurements were taken, each during four seconds of insufflation, and the results averaged (milliliters (ml) per second (sec)) for each device.

Results:

Flow rates obtained using both resuscitation bags, tank oxygen, and regulated wall oxygen were extremely low (adult 215 ±20 ml/sec; pediatric 195 ±19 ml/sec; tank 358 ±13 ml/sec; wall at 15 l/min 346 ±20 ml/sec). Flow rates of 1,394 ±13 ml were obtained using wall oxygen with the regulator wide open. Using the JV with the regulator set at 50 pounds per square inch (psi), a flow rate of 1,759 ±40 was obtained.These were the only two methods that produced flow rates high enough to provide an adequate tidal volume to an adult.

Conclusions:

Resuscitation bags should not be used to ventilate adult patients through a 14-gauge, transtracheal catheter. Jet ventilation is needed when percutaneous transtracheal ventilation is attempted. If jet ventilation is attempted using oxygen supply tubing, it must be connected to an unregulated oxygen source of at least 50 psi.

Aspiration in transtracheal jet ventilation

BACKGROUND

Transtracheal jet ventilation (TJV) has been used successfully for managing difficult airways. However, there are some controversies regarding pulmonary aspiration. It has been shown that TJV caused no aspiration as long as the frequency of ventilation was kept higher than 60/ min. On the other hand, it has been demonstrated that manual translaryngeal jet ventilation at 20 breaths per minute also provided good protection from aspiration even with 30-degree head-up position. The purpose of this study was to reevaluate this controversy with observation of the trachea and the lungs together during TJV.

METHODS

Eight mongrel dogs were anesthetized, paralyzed and ventilated transtracheally with jet ventilator at frequencies variying from 600 to 10/min. The airway pressures below and above the jetting port were measured. The mouth of the dog was then filled with barium and chest x-rays were taken 5 minutes after each different jetting frequency.

RESULTS

No tracheal or pulmonary aspiration was observed on chest x-rays as long as the frequencies were set above 80 per minute. With frequencies of 60 per minute, barium was seen in the trachea but at a level above the jetting port. Slowing down the frequency to 10/min did not affect the level of barium.

CONCLUSION

No aspiration could be visualized on chest x-rays. The mechanism for preventing pulmonary aspiration is thought to be due to forceful continuous gas outflow through the larynx. The epiglottis seems to play no role in this mechanism. The limited tracheal aspiration was probably due to the existence of a negative pressure in the upper airway. Cessation of the TJV will cause a drop in this pressure gradient and results in pulmonary aspiration. It is recommended that the airway above the jetting port be totally cleansed prior to discontinuation of the tanstracheal jet ventilation.