Low-frequency Jet Ventilation Research Articles

The Impact of Tracheal Stenosis on Distal Airway Pressure with Jet Ventilation.

This study investigates the effects of tracheal stenosis on distal airway pressure during low-frequency jet ventilation (LFJV) in tracheal stenosis resection procedures, focusing on variables like stenosis size, depth, scope type, and inlet pressure. A 3D-printed human airway model was employed, featuring inserted tracheal stenoses of varied sizes and depths. Distal airway pressure was measured with 16 pressure transducers, and data were processed via MATLAB. The study varied stenosis size, depth, scope type, and inlet pressure during five sequential jet bursts under LFJV. Using a subglottiscope resulted in significantly reduced distal airway pressure compared to a laryngoscope. Interestingly, neither stenosis size nor depth significantly influenced distal airway pressure. However, increased distance between the scope and stenosis raised normalized pressure. A linear rise in normalized distal airway pressure was noted with increased inlet pressure, regardless of stenosis dimensions. In this model, scope type and inlet pressure were noted to be significant determinants of distal airway pressure, while stenosis size and depth were not. The distance between the scope and the stenosis did influence distal pressures. These findings may have clinical implications for managing airway pressures in patients undergoing LFJV, potentially reducing the risk of ventilator-induced lung injury. NA (Basic Research) Laryngoscope, 134:2300-2305, 2024.

Manual jet ventilation to rescue a patient with pinhole tracheal stenosis: A case report

Airway management of patients with tracheal stenosis is highly challenging and even establishing a surgical airway may be difficult in these patients. A 24 year old female developed pinhole tracheal restenosis after undergoing tracheal web resection and reconstruction. After other modes of ventilation had failed, we used the Manual jet ventilator endotracheal tube assembly as a rescue device and performed intermittent low-frequency jet ventilation until a definitive surgical airway could be established.: Central airway obstruction in severe tracheal stenosis can cause life-threatening hypoxia. Jet ventilation through the pin hole opening buys some time for the surgeon to secure the airway.

Low Pressure Low Frequency Jet Ventilation: Techniques, Safety and Complications

Manual jet ventilation is a specialized oxygenation and ventilation technique that is not available in all facilities due to lack of technical familiarity and fear of complications. The objective is to review our center's 15 year experience with low pressure low frequency jet ventilation (LPLFJV). Retrospective review of procedures utilizing LPLFJV from 2005 to 2019 were performed collecting patient demographic, surgery type and complications. Fisher exact test, Chi square, and t-test were used to determine statistical significance. Four hundred fifty-seven patients underwent a total of 891 microlaryngeal surgeries-279 cases for voice disorders, 179 for lesions, and 433 for airway stenosis. The peak jet pressure for all cases did not exceed 20 psi and average peak pressure for the last 100 procedures in this case series was 14.9 ± 4.6 psi. The average lowest oxygen saturation for all cases was 95% ± 0.6%. Brief intubation was required in 154 cases (17%). Surgical duration was significantly longer for cases requiring intubation P < .001. The need for intubation was not associated with smoking or cardiopulmonary disease, but was strongly associated with body mass index (BMI). Intubation rates were 7% for normal weight (BMI < 25, N = 216), 13% for overweight (BMI 25-30, N = 282), 24% for obese (BMI 30-40, N = 342), and 37% for morbidly obese (BMI > 40, N = 52) patients. Three patients developed respiratory distress in the recovery unit and 2 patients required intubation. LPLFJV assisted by intermittent endotracheal intubation is an exceedingly safe and effective intraoperative oxygenation and ventilationmodality for a broad variety of laryngeal procedure.

The Effects of Laryngoscope Shape and Needle Position on Distal Airway Pressure in Jet Ventilation.

Laryngoscopes and subglottiscopes of multiple shapes and lengths are used in airway surgery to maintain an open airway; protect the trachea; and provide a place to mount the light, evacuator, and ventilation needle. Despite differences in scopes and ventilation needle mounting positions, the same jet pressures are typically used. We hypothesized that different scopes and scope configurations would affect distal airway pressure magnitude and homogeneity. A laboratory investigation of distal airway pressures in a lung modelduring low frequency jet ventilation. A three-dimensional airway model based on the computed tomography scan of a 15-year old healthy male was fabricated with pressure transducers at the fifth airway generation. A laryngoscope and a subglottiscope were each mounted in the model coaxial with the trachea. Parameters including scope depth and needle mounting position were adjusted, and the effects on distal airway pressure were recorded. Changing the scope depth from 1 to 3 cm past the laryngeal inlet had a limited effect on distal airway pressure. Needle mounting angle in the laryngoscope strongly influenced distal airway pressure, with a 7° angle change yielding a 67.5% increase. Compared to a loose needle centered in the trachea 1 cm past the laryngeal inlet, the subglottiscope and laryngoscope showed up to 16% and 150% increases in distal airway pressure, respectively. Different scopes or changes in the configuration, such as the needle angle, strongly influence distal airway pressure. Our findings indicate that different jet pressures are required for different scopes and that a stable needle mount is a critical design consideration to prevent changes in minute ventilation due to needle movement. NA (Basic Research) Laryngoscope, 131:E354-E357, 2021.

Ventilation strategy and anesthesia management in patients with severe tracheal stenosis undergoing urgent tracheal stenting.

Stenting of airway stenosis is a common procedure in specialized centers. The aim of this study was to summarize our clinical experience in ventilation strategy and anesthesia management of patients undergoing urgent tracheal stenting. Clinical data of 22 patients with severe tracheal stenosis who underwent urgent endoscopic placement of a tracheal stent during a 2-year period were retrospectively reviewed. The efficacy and safety of different ventilation strategies and veno-arterial extracorporeal membrane oxygenation (ECMO), individualized based on the cause and location of tracheal narrowing, were evaluated. Sufficient ventilation was successfully established in all patients; ECMO was used in five patients with stenosis in the mid-trachea who were unable to tolerate conventional intubation; a laryngeal mask airway (LMA) was used in five patients with post-intubation tracheal stenosis; a cuffed tracheal tube was used in eight patients with lower tracheal stenosis; and low-frequency jet ventilation in rigid bronchoscopy was used in four patients with mid- or lower tracheal stenosis. Tracheal stents were successfully placed and there were significant improvements in dyspnea. There were significant increases in the partial pressure of carbon dioxide in patients ventilated with the LMA and cuffed tracheal tube. There was no hypoxia during the operative period. Establishment of effective airway ventilation in patients with severe tracheal stenosis should be based on the cause, location, and severity of tracheal narrowing. Veno- arterial ECMO may be considered in patients with severe stenosis, if they are judged unable to tolerate conventional ventilation or jet ventilation.

Anesthetic management for the insertion of a self-expandable metallic tracheal stent under venovenous extracorporeal membrane oxygenation

Anesthetic management for the insertion of a self-expandable metallic tracheal stent under venovenous extracorporeal membrane oxygenation

Reply to the Editor—General Anesthesia and Catheter Ablation for Atrial Fibrillation

We thank Goode et al for their interest in our study. We would like to point out that although high-frequency jet ventilation (HFJV) is a safer ventilation technique than conventional hand jet ventilation (or low-frequency jet ventilation [LFJV]), different complications are specifically associated with HFJV.1,2 These complications include problems with humidification and warming, high gas flow rates, and rapid increases in lung volume that might cause lung injury through the generation of shear forces at the interface of compliant and atelectatic airways.

Airway management and anesthesia in neonates, infants and children during endolaryngotracheal surgery

Endolaryngotracheal surgery in neonates, infants and children poses a big challenge for both anesthesiologist and surgeon. The narrowness of the airways and the great variability of the pathological lesions necessitate close collaboration between the surgical and the anesthesia team to provide optimal operating conditions and ensure adequate ventilation and oxygenation. Sixty-two anesthetic records of endolaryngotracheal surgical procedures in neonates, infants and children with ASA physical status 1-3 were analyzed retrospectively. Anesthesia was administered as total intravenous anesthesia; propofol supplemented with remifentanil. Ventilation was performed as supraglottic, superimposed high-frequency jet ventilation via jet laryngoscope with integrated jet nozzles. Age was 58.93 (SD 35.40) months, range 3 weeks to 14 years; body weight 17.83 (SD 8.79) kg, range 2.4-50 kg. The capillary pCO(2) 5 min after the start of the surgical procedure (n = 62) was 40.01 (SD 7.71) mmHg and after 20 min (n = 24) 41.77 (SD 7.12) mmHg. No hypoxemia (oxygen saturation <90%) developed. All patients were hemodynamically stable during jet ventilation. Barotrauma or gas insufflation in the stomach did not occur. No perioperative tracheostomy was necessary. Laryngospasm occurred in one child during emergence from anesthesia. Four infants received postoperative conventional respirator therapy in the ICU overnight. Supraglottic superimposed high-/low-frequency jet ventilation via jet laryngoscopes with integrated jet nozzles is a minimally invasive ventilation technique for neonates, infants and children in endolaryngotracheal surgery, which allows an unimpaired operating field for the surgeon especially in LASER surgery.

Impact of body mass index (BMI) on ventilation during low-frequency jet ventilation

Percutaneous trans-tracheal jet ventilation (PTJV) is an alternative ventilatory approach in airway surgery. We evaluated the effects of body mass index (BMI) on ventilation during low-frequency jet ventilation. Forty-two patients undergoing micro-laryngeal surgery under total anesthesia were studied. Low-frequency jet ventilation was applied through an injector inserted into the trachea via cricothyroid membrane; ventilation was assessed during the operation by arterial blood gas sampling. The age range of the patients was 43.54 +/- 12.04 years, weight was 69.97 +/- 11.66 kg, and BMI 24.80 +/- 2.78 (mean +/- SD). There was a strong correlation (P < 0.05) and a good correspondence between the BMI and mean PaCO(2), and arterial pH. This method was effective in maintaining gas exchange in the presence of micro-laryngeal surgery for low-BMI patients. It provided a nice visible surgical field, avoiding the use of combustible material inside the larynx or trachea.

Tubeless combined high-frequency jet ventilation for laryngotracheal laser surgery in paediatric anaesthesia.

High-frequency jet ventilation (HFJV) is an alternative ventilatory approach in airway surgery and for facilitating gas exchange in patients with pulmonary insufficiency. We have developed a new technique of combined HFJV utilising two superimposed jet streams. In this study we describe the application of tubeless supralaryngeal HFJV during laryngotracheal laser surgery in infants and children. Tubeless combined HFJV characterised by the simultaneous supralaryngeal application of a low-frequency (LF) and a high-frequency (HF) jet stream was evaluated in a clinical study in 10 children undergoing elective laryngotracheal CO2 laser surgery. Additionally, pressure and flow characteristics were determined with the use of a paediatric test lung. HFJV was applied by means of a modified Kleinsasser laryngoscope with integrated metal injectors. In addition to pulse oximetry, monitoring of ECG, heart rate and blood pressure, supraglottic airway pressure was measured and arterial blood gases were analysed. Tubeless combined HFJV was used in 10 infants and children (mean age 4.6 yr, range 2 months-10 years) undergoing 17 consecutive endoscopic procedures with CO2 laser microsurgery of the larynx or the trachea under general anaesthesia. The mean duration of supralaryngeal HFJV was 46 min (range 15-75 min). Mean driving pressures of the HF and the LF jet streams were 0.75 bar and 0.95 bar, respectively. Inspiratory oxygen ratios were in the range 0.4-1.0. HFJV resulted in mean PaO2 and PaCO2 values of 19.7 kPa and 6.1 kPa, respectively. No complications during HFJV were observed. In the test lung, combined HFJV applied with driving pressures of 0.7-1.0 bar and 0.9-1.2 bar for HF and LF jet ventilation, respectively, resulted in maximum peak and baseline distal airway pressures of 17.6 cm H2O and 5.4 cm H2O, respectively. The application of the combined double frequency HFJV was effective in maintaining gas exchange in the presence of laryngeal or tracheal stenoses. It provided good visibility of anatomical structures and offered space for surgical manipulation, avoiding the use of combustible material inside the larynx or trachea.

SHFJV. Jet-adapter for application of superimposed high-frequency jet ventilation (SHFJV) via a tube in intensive care: a new technique

Despite advances and technical developments in the area of intensive care medicine it has not been possible to lower the mortality of patients with pulmonary insufficiency. Therefore, alternative ventilation strategies have been developed and applied. One of these ventilation techniques is superimposed high-frequency jet ventilation (SHFJV). For optimal application of SHFJV we designed a special jet-adapter. This jet-adapter made of plastic consists of a T-piece and four central, small-bore cannulas and can be connected to any commercially available endotracheal tube. Therefore, it does not require reintubation with an endotracheal jet tube when beginning SHFJV. The simultaneous high-frequency and low-frequency jet ventilation is performed over two jet-nozzles that have been designed according to optimal flow dynamic measurements. Two further cannulas are used for continuous airway pressure monitoring and humidification of the applied gases. A pre-warmed and humidified bias flow with exactly defined oxygen concentration is led through the cross-part of the T-piece for gas entrainment. Additionally, the cross-part contains a port that can be opened for endotracheal suctioning or bronchoscopy and makes disconnection of the jet adapter from the endotracheal tube for either purpose unnecessary. The jet adapter can be used: (1) to apply SHFJV; (2) to measure airway pressures continuously; (3) to humidify and warm inspired gases; (4) to administer medications or add nitrous oxide by the inspiratory route, enabling combination with new therapeutic possibilities in the management of patients with severe ARDS.

Comparison of automated and manual ventilation in a prehospital pediatric model

Objective. Portable transport ventilators (TV) and demand valves (DV) may be effective and easy-to-use alternatives to bag-valve (BV) for prehospital ventilation of adults. The purpose of the study was to determine whether such devices maintain arterial blood gases and airway pressures similar to those for BV in a pediatric swine model. Method. This study was a prospective, randomized, crossover design using immature swine (9.6 ± 0.9 kg) to model ventilation in small children. Anesthetized, intubated, paralyzed, and cannulated animals were ventilated initially on standard mechanical hospital ventilation (HV). They were then assigned in random order to 10-minute intervals of ventilation using BV, TV, low-frequency jet ventilation (JV), and DV. Data were analyzed using repeated-measures ANOVA and Tukey multiple comparisons (alpha = 0.05). Results. The PaO2 exceeded 90 mm Hg for all animal/ventilation combinations. Blood PaCO2 was lower for BV and DV than it was for TV, JV, or HV. In contrast, blood pH was higher for BV and DV than it was for TV, JV, or HV. Peak airway pressure was higher for BV than it was for HV, TV, or JV; it was lower for JV than it was for HV, TV, or BV. Conclusion. This animal model suggests that automated TV and JV may provide more effective ventilation of children than do manual BV or DV devices. Although promising, these findings require application in children under prehospital emergent conditions.

Tubeless laryngotracheal surgery in infants and children via jet ventilation laryngoscope.

We present the first use of tubeless superimposed combined high- and low-frequency jet ventilation (SHFJV) with a jet laryngoscope in laryngotracheal surgery in infants and children. Twenty-eight patients underwent 53 operative procedures. The average age of the patients was 7.3 years. The most common diagnoses were laryngeal papillomatosis and subglottic stenosis. The duration of jet ventilation averaged 33 min. The gas exchange was sufficient in each case. The advantages of SHFJV in the surgery of the laryngotracheal area in infants and children are optimal view at the larynx and trachea, maximum space for the handling, application of the laser without risks, no time limitation, suitability for stenosis, and neither anesthetic nor surgical complications.

PRESSURE SUPPORT VENTILATION USING A NEW TRACHEAL GAS INJECTION TUBE

In order to explore new types of jet ventilation, we tested a tracheal gas injection tube (TGIT) which included six thin capillaries and provided high pressure injection. The driving pressure was chosen to yield a plateau of inspiratory tracheal pressure of 10 cm H2O. An original controller was built to monitor spirometry and trigger injection in order to deliver both pressure controlled ventilation (PCVTGIT) and a new mode of inspiratory pressure support jet ventilation (IPSTGIT). The PVCTGIT mode maintained the same end-tidal carbon dioxide concentration as conventional ventilation with the same tidal and minute ventilation. We studied 10 patients after abdominal surgery. During spontaneous breathing, the patients were allowed to breathe through the tube, successively with and without IPSTGIT. IPSTGIT, compared with spontaneous breathing increased minute ventilation (from 5.7 (SD 1.6) to 7.1 (1.7) litre min-1) (P less than 0.001). It reduced the total work of breathing (from 0.625 (0.223) to 0.263 (0.151) J litre-1, respectively) (P less than 0.01) and the occlusion pressure (from 2.62 (1.28) to 1.36 (0.74) cm H2O, respectively) (P less than 0.01). It is concluded that this TGIT used with a specific system for sensing and triggering ventilation allows inspiratory pressure support during low frequency jet ventilation.

Aspiration during manual low-frequency jet ventilation

Aspiration during manual low-frequency jet ventilation

声帯注入手術（ラリンゴマイクロ下）におけるＬｏｗ Ｆｒｅｑｕｅｎｃｙ Ｊｅｔ Ｖｅｎｔｉｌａｔｉｏｎの使用経験

During cordal injection therapy (a kind of laryngomicrosurgery), a patient needs to be kept still and ventilation needs to be maintained at an adequate level. In addition, the vision of the surgical field (particularly the posterior region of the vocal fold) should not be obstructed. Until now, various methods of anesthesia during cordal injection therapy have been assessed; they include local anesthesia, general anesthesia with tracheal intubation, general anesthesia without intubation (e. g., neuroleptanalgesia) and high frequency jet ventilation (HFJV). We have recently tried low frequency jet ventilation (LFJV) for anesthesia during cordal injection surgery under laryngomicroscopy. The use of this technique allowed us to keep the vision of the posterior region of the vocal fold almost unobstructed, to prevent elevation of PaCO2 while PaO2 at a sufficiently high level during operation. This method seems to provide an excellent means of anesthesia during this kind of surgery.