High frequency jet ventilation through mask contributes to oxygen therapy among patients undergoing bronchoscopic intervention under deep sedation.

BACKGROUND: High frequency jet ventilation (HFJV) is an open ventilating technique to maintain ventilation for emergency or difficult airway. However, whether jet ventilation or conventional oxygen therapy (COT) is more effective and safe in maintaining adequate oxygenation, is unclear among patients with airway stenosis during bronchoscopic intervention (BI) under deep sedation. METHODS: A prospective randomized cohort study was conducted to compare COT (high flow oxygen) with normal frequency jet ventilation (NFJV) and HFJV in oxygen supplementation during BI under deep sedation from March 2020 to August 2020. Patients receiving BI under deep sedation were randomly divided into 3 parallel groups of 50 patients each: the COT group (fractional inspired oxygen (FiO2) of 1.0, 12 L/min), the NFJV group (FiO2 of 1.0, driving pressure of 0.1 MPa, and respiratory rate (RR) 15 bpm) and the HFJV Group (FiO2 of 1.0, driving pressure of 0.1 MPa, and RR of 1200 bpm). Pulse oxygen saturation (SpO2), mean arterial blood pressure and heart rate were recorded during the whole procedure. Arterial blood gas was examined and recorded 15 min after the procedure was initiated. The procedure duration, dose of anesthetics, and adverse events during BI in the three groups were also recorded. RESULTS: A total of 161 patients were enrolled, with 11 patients excluded. The clinical characteristics were similar among the three groups. PaO2 of the COT and NFJV groups was significantly lower than that of the HFJV group (P < 0.001). PaO2 was significantly correlated with ventilation mode (P < 0.001), body mass index (BMI) (P = 0.019) and procedure duration (P = 0.001). Multiple linear regression showed that only BMI and procedure duration were independent influencing factors of arterial blood gas PaO2 (P = 0.040 and P = 0.002, respectively). The location of airway lesions and the severity of airway stenosis were not statistically correlated with PaCO2 and PaO2. CONCLUSIONS: HFJV could effectively and safely improve intra-operative PaO2 among patients with airway stenosis during BI in deep sedation, and it did not increase the intra-operative PaCO2 and the risk of hypercapnia. PaO2 was correlated with ventilation mode, BMI and procedure duration. Only BMI and procedure duration were independent influencing factors of arterial blood gas PaO2. PaCO2 was not correlated with any preoperative factor. TRIAL REGISTRATION: Chinese Clinical Trial Registry. Registration number, ChiCTR2000031110 , registered on March 22, 2020.

Current views of complications associated with neonatal ventilation.

Infants born prematurely require external respiratory support device like ventilation for the purpose of life saving. However, these ventilation machines have complications that sometimes unfortunately result in morbidity. New ventilation techniques have been developed to prevent morbidity, but have yet to be fully evaluated. The present review article would discuss current aspects of this life saving gear especially for pediatric patients in clinical setting. Besides basic ventilation apparatus, advancements in the filed like proportional assist ventilation, volume targeted ventilation would be discussed.

Transtracheal jet oxygenation: Comparing the efficacy and safety of two self-made Y-connector devices with the ENK oxygen flow modulator™ in an infant animal model.

BACKGROUND: Self-made Y-connector jet-oxygenation devices with wide-bore expiratory port have been described but not evaluated in infant models. Little is known about the effect of oxygen flow rates on jet oxygenation via transtracheal cannula. AIMS: The aim of this study was to compare two self-made Y-connector jet-oxygenation devices against the ENK oxygen flow modulator™, and the effects of three different oxygen flow rates based on body weight, in both unobstructed and obstructed airways, on the time to re-oxygenate in a rabbit infant model. The aim was also to assess the effectiveness of an oxygen flow rate of 1 L/min, for re-oxygenation using ENK oxygen flow modulator™. METHODS: Nine rabbits were grouped in threes: Group 1 had a Y-connector attached to an intravenous infusion tubing, Group 2 the same Y-connector attached to a perfusion oxygenator tubing and Group 3, ENK oxygen flow modulator™. From oxygen saturations of 75%, the rabbits were jet oxygenated using their assigned device for 10 minutes at each flow rate of 1 L/kg/min, 1.5 L/kg/min and 2 L/kg/min with their airways unobstructed and later, obstructed. Group 3 had additional experiments involving an absolute oxygen flow rate of 1 L/min. RESULTS: All devices resulted in rapid re-oxygenation within 40 seconds at flow rates of 1 L/kg/min. Oxygen flow rates beyond 1 L/kg/min in obstructed airways resulted in high airway pressures. All rabbits in Group 3 with obstructed airways died from barotrauma when jet oxygenated at a flow rate of 1.5 L/kg/min. When an oxygen flow rate of 1 L/min was used in Group 3, there was a failure to re-oxygenate to SpO2 90% within 120 seconds in some rabbits. CONCLUSION: Our animal model results suggest that self-made Y-connector jet-oxygenation devices with wide-bore expiratory port are efficacious and perhaps safer than ENK oxygen flow modulator™ in obstructed airways, and jet oxygenation with minimal oxygen flow rates starting at 1 L/kg/min or (age [years] + 4) L/min, whichever lower, should be considered.

Supraglottic jet oxygenation and ventilation enhances oxygenation during upper gastrointestinal endoscopy in patients sedated with propofol: a randomized multicentre clinical trial.

BACKGROUND: Hypoventilation is the main reason for hypoxia during upper gastrointestinal endoscopy procedures with sedation. The key to preventing hypoxia is to maintain normal ventilation during the procedure. We introduced supraglottic jet oxygenation and ventilation (SJOV) through a new Wei nasal jet tube (WNJ) to reduce the incidence of hypoxia in patients sedated with propofol during upper gastrointestinal endoscopy procedures. METHODS: In a multicentre, prospective randomized single-blinded study, 1781 outpatients undergoing routine upper gastrointestinal endoscopy who were sedated with propofol by an anaesthetist were randomized into the following three groups: the supplementary oxygen via nasal cannula group [nasal cannula oxygen: O 2 (2 litres min -1 ) was administered via a nasal cannula]; the supplementary oxygen via WNJ group [WNJ oxygen: O 2 (2 litres min -1 ) was administered through a WNJ]; and the SJOV via WNJ group (WNJ SJOV: SJOV was administered via WNJ) at three centres from March 2015 to July 2016. The primary outcome of interest was the incidence of hypoxia (peripheral oxygen saturation of 75-89%). Other adverse events were also recorded. RESULTS: Supraglottic jet oxygenation and ventilation decreased the incidence of hypoxia from 9 to 3% ( P <0.0001). No severe hypoxia occurred in the WNJ SJOV group, one instance occurred in the WNJ oxygen group, and two instances were observed in the nasal cannula oxygen supply control group. Supraglottic jet oxygenation and ventilation-related minor adverse events increased significantly within 1 min after the procedure but decreased 30 min later. CONCLUSIONS: The use of SJOV during upper gastrointestinal endoscopy for patients who are sedated with propofol reduces the incidence of hypoxia, with minor and tolerable adverse events. Supraglottic jet oxygenation and ventilation has a favourable risk-to-benefit ratio and may improve patient safety. CLINICAL TRIAL REGISTRATION: NCT02436018.

Transtracheal jet ventilation in the 'can't intubate can't oxygenate' emergency: a systematic review.

BACKGROUND: Transtracheal jet ventilation (TTJV) is recommended in several airway guidelines as a potentially life-saving procedure during the 'Can't Intubate Can't Oxygenate' (CICO) emergency. Some studies have questioned its effectiveness. METHODS: Our goal was to determine the complication rates of TTJV in the CICO emergency compared with the emergency setting where CICO is not described (non-CICO emergency) or elective surgical setting. Several databases of published and unpublished literature were searched systematically for studies describing TTJV in human subjects. Complications were categorized as device failure, barotrauma (including subcutaneous emphysema), and miscellaneous. Device failure was defined by the inability to place and/or use the TTJV device, not patient survival. RESULTS: Forty-four studies (428 procedures) met the inclusion criteria. Four studies included both emergency and elective procedures. Thirty studies described 132 emergency TTJV procedures; 90 were CICO emergencies. Eighteen studies described 296 elective TTJV procedures. Device failure occurred in 42% of CICO emergency vs 0% of non-CICO emergency (P<0.001) and 0.3% of elective procedures (P<0.001). Barotrauma occurred in 32% of CICO emergency vs 7% of non-CICO emergency (P<0.001) and 8% of elective procedures (P<0.001). The total number of procedures with any complication was 51% of CICO emergency vs 7% of non-CICO emergency (P<0.001) and 8% of elective procedures (P<0.001). Several reports described TTJV-related subcutaneous emphysema hampering subsequent attempts at surgical airway or tracheal intubation. CONCLUSIONS: TTJV is associated with a high risk of device failure and barotrauma in the CICO emergency. Guidelines and recommendations supporting the use of TTJV in CICO should be reconsidered.

[Comparison of the Effectiveness of Different Supraglottic Ventilation Methods during Bronchial Thermoplasty].

OBJECTIVE: To compare the effectiveness of high-frequency jet ventilation via Wei jet nasal airway and controlled ventilation with improved laryngeal mask airway during bronchial thermoplasty. METHODS: Twenty-eight patients undergoing bronchial thermoplasty were equally divided into two groups: group A (high-frequency jet ventilation through Wei jet nasal airway) and group B (controlled ventilation with improved laryngeal mask airway). Pulse oxygenation,heart rate,and mean arterial blood pressure were recorded after entering the operating room (T0), 1 minute after administration/induction (T1), bronchoscope inserting (T2), 15 minutes (T3)/30 minutes (T4)/45 minutes (T5) after ventilation,at the end of the operation (T6), and at the recovery of patients' consciousness (T7). The pH,arterial oxygen partial pressure,and arterial carbon dioxide partial pressure were recorded at T0, T4, and T6. The endoscope indwelling duration,operative time,patients' awakening time,adverse events during anesthesia,satisfactions of patients and operators, anesthesic effectiveness were also recorded. RESULTS: The arterial carbon dioxide partial pressur in group A at T4 and T6 were significantly higher than in group B (P<0.05). The pH in group A at T4 and T6 was significantly lower than in group B (P<0.05). The endoscope indwelling duration and the operative time in group B were significantly shorter than in group A (P<0.05) while the recovery of consciousness in group B was significantly longer than in group A (P<0.05). The satisfaction for operators and the efficacy of anesthesia in group B were better than in group A (P<0.05). The number of adverse events in group B was significantly smaller than in group A (P<0.05). CONCLUSION: The improved laryngeal mask airway with controlled ventilation is more suitable for bronchial thermoplasty.

Percutaneous transtracheal ventilation in an obstructed airway model in post-apnoeic sheep.

BACKGROUND: Temporizing oxygenation by percutaneous transtracheal ventilation (PTV) is a recommended emergency technique in 'can't intubate, can't oxygenate' (CICO) situations. Barotrauma risk increases if expiration is obstructed. The Ventrain(®) is a new PTV device that assists expiration. Our aim was to compare key physiological outcomes after PTV with the Ventrain and the Manujet(®) in a large animal obstructed airway model. METHODS: Five anaesthetized sheep had post-apnoea PTV performed for 15 min using the Ventrain or Manujet with the proximal airway completely or critically obstructed, yielding four ventilation protocols per sheep. After apnoeic desaturation ([Formula: see text]70%), a 4 s rescue breath was delivered. Subsequent 2 s breaths were delivered whenever the airway pressure fell <10 cm H2O. RESULTS: Both devices achieved rapid re-oxygenation. There were marked device differences (Ventrain vs Manujet) in peak airway pressures with rescue (16 vs 40 cm H2O) breaths, minute ventilation (4.7 vs 0.1 litre min(-1)), and end-protocol pH (7.34 vs 7.01). There was no clinical evidence of barotrauma in any sheep after any ventilation protocol. An equilibration phase prevented large subatmospheric intrathoracic pressure development with Ventrain ventilation. CONCLUSIONS: The Ventrain provided stable oxygenation and effective ventilation at low airway pressures during emergency PTV in critically obstructed airways. The Manujet provided effective temporizing oxygenation in this situation with hypoventilation necessary to minimize barotrauma risk. The nature and extent of airway obstruction may not be known in a CICO emergency but an understanding of device differences may help inform optimal ventilation device and method selection.

Time to adequate oxygenation following ventilation using the Enk oxygen flow modulator versus a jet ventilator via needle cricothyrotomy in rabbits.

INTRODUCTION: Limited information is available on the management of the 'cannot intubate, cannot ventilate' (CICV) situation in infants. We compared the time to achieve adequate oxygenation following rescue ventilation using the Enk oxygen flow modulator (OFM) with a jet ventilator in a simulated CICV situation using the rabbit as an infant respiratory model. METHODS: Following institutional ethics committee approval, needle cricothyrotomy was performed under direct vision in nine anesthetized rabbits following surgical exposure of the larynx. After ensuring adequate level of anesthesia and analgesia, and confirming proper positioning of the 18G cannula, apnea was induced by the administration of myorelaxant and the SpO2 was allowed to drop to 75% before initiating rescue ventilation via either the OFM or jet ventilator. RESULTS: Five rabbits were ventilated with the OFM and four with the jet ventilator. Ventilation was maintained with either device for 15 min. All rabbits were successfully rescued using either device. There was no statistical difference in the time required for SpO2 to return to 80%, 85%, 90%, and 95%. CONCLUSIONS: Both devices facilitated successful rescue ventilation through a needle cricothyrotomy.

[High-frequency jet ventilation in otorhinolaryngology - surgical and anaesthesiologic issues]. / Die Hochfrequenz-Jet-Ventilation in der HNO-Heilkunde - chirurgische und anästhesiologische Aspekte.

BACKGROUND: High-frequency jet ventilation (HFJV) through thin catheters creates more room for surgical procedures in laryngotracheal surgery, while few contraindications exist. In contrast, the anaesthesiologist has to cope with reduced monitoring and numerous contraindications. Therefore, every participating discipline has to thoroughly know the method. We report our experiences with HFJV and focus on relevant points, which contribute to a safe and cooperative procedure. MATERIAL AND METHODS: We performed a retrospective chart review for patients, who were operated for benign laryngotracheal lesions using HFJV at the Hannover Medical School, Department of Otorhino-Laryngology between June 2012 and February 2013. We analyze patient characteristics, complications and important anaesthesiologic and operative steps. RESULTS: A total of 46 cases of microlaryngoscopies and tracheoscopies were included in this study. The median body mass index was 27 kg/m(2). According to the ASA-classification, 24% of patients were categorized class I, 54% class II and 22% class III. In 2 cases we had reversible, peripheral desaturations down to 70%. In one case, emergent re-intubation with an endotracheal tube was inevitable due to rapid desaturation below 50%. Further complications were not observed. CONCLUSION: HFJV represents a safe ventilation approach in laryngotracheal surgery, when patients are thoroughly selected. Especially the surgeon benefits from more room in the operating field. Obesity, reflux and cardiopulmonary diseases have to be evaluated well, as these can represent relative contraindications. Individual decisions can be made under consideration of all comorbidities.

External Jet Nebulization and Measured Ventilator Performance.

BACKGROUND: During invasive ventilation, external flow jet nebulization results in increases in displayed exhaled tidal volumes (VT). We hypothesized that the magnitude of the increase is inaccurate. An ASL 5000 simulator measured ventilatory parameters over a wide range of adult settings: actual VT, peak inspiratory pressure (PIP), and time to minimum pressure. METHODS: Ventilators with internal and external flow sensors were tested by using a variety of volume and pressure control modes (the target VT was 420 mL). Patient conditions (normal, COPD, ARDS) defined on the ASL 5000 were assessed at baseline and with 3.5 or 8 L/min of added external flow. Patient-triggering was assessed by reducing muscle effort to the level that resulted in backup ventilation and by changing ventilator sensitivity to the point of auto-triggering. RESULTS: Results are reported as percentage change from baseline after addition of 3.5 or 8 L/min external flow. For ventilators with internal flow sensors, changes in displayed exhaled VT ranged from 10% to 118%, however, when using volume control, actual increases in actual VT and PIP were only 4%-21% (P = .063, .031) and 6%-24% (P = .25, .031), respectively. Changes in actual VT correlated closely with changes in PIP (P < .001; R2 = 0.68). For pressure control, actual VT decreased by 3%-5% (P = .031) and 4%-9% (P = .031) with 3.5 and 8 L/min respectively, PIP was unchanged. With external flow sensors at the distal Y-piece junction, volume and pressure changes were statistically insignificant. The time to minimum pressure increased at most by 8% (P = .02) across all modes and ventilators. The effects on muscle pressure were minimal (∼1 cm H2O), and ventilator sensitivity effects were nearly undetectable. CONCLUSIONS: External flow jet nebulization resulted in much smaller changes in volume than indicated by the ventilator display. Statistically significant effects were confined primarily to machines with internal flow sensors. Differences approached the manufacturer-reported variation in ventilator baseline performance. During nebulizer therapy, effects on VT can be estimated at the bedside by monitoring PIP.

Jet or intensive care unit ventilator during simulated percutaneous transtracheal ventilation: a lung model study.

BACKGROUND: Percutaneous transtracheal ventilation (PTV) via a jet ventilator (PTJV) is considered a rescue technique in difficult airway management. However, whether a conventional ventilator can generate adequate ventilation via PTV is not known. Our goal was to evaluate the tidal volume (V(T)) generated by a conventional ventilator during simulated PTV compared with PTJV in a lung model. METHODS: A lung model simulating an adult lung was used. A catheter was inserted through the artificial trachea and connected to either a jet ventilator or a conventional ventilator. The direction of catheter insertion was perpendicular to the trachea, pointing towards the lung and away from the lung. The jet ventilator was operated at 344.7 kPa. The conventional ventilator was operated in the pressure mode at peak inspiratory pressures of 40-90 cm H(2)O. RESULTS: The jet ventilator generated larger V(T) [817 (336) ml] when the catheter was pointing towards the lung than when pointing away from the lung or perpendicular to the trachea [121 (41) and 69 (24) ml, respectively, P<0.01]. With the conventional ventilator, changes in V(T) at different direction of catheter insertion were much less [222 (81) ml catheter pointing towards the lung, 229 (121) ml perpendicular to the trachea, and 187 (97) ml away from the lung]. CONCLUSIONS: Our result demonstrated that PTJV was effective only when the catheter was pointing towards the lung and requires high operating pressure. A conventional ventilator can generate reasonable minute ventilation through the transtracheal catheter less dependent on directions of catheter insertion and should be considered during emergent PTV.

Methods of administering superimposed high-frequency jet ventilation and the associated risk for aspiration in a model of tracheal bleeding.

BACKGROUND: To determine the suitability of different superimposed high-frequency jet ventilation (SHFJV) application methods during tracheal bleeding. OBJECTIVE: To determine the effect of SHFJV on the aspiration of blood during tracheal bleeding. METHODS: A test lung was ventilated using SHFJV via a rigid endoscope, a jet laryngoscope and a 4-lumen jet catheter. Packed red blood cells (PRBCs) were injected into the artificial trachea caudally to the rigid endoscope and jet laryngoscope ventilation, and both caudally and cranially during ventilation via the 4-lumen jet catheter, and the migration of PRBCs during ventilation was studied using continuous video recording. RESULTS: Migration of blood into the lower respiratory tract did not occur during SHFJV via the rigid endoscope and jet laryngoscope and via the 4-lumen jet catheter with the bleeding caudal to ventilation source. If the bleeding was cranial to the 4-lumen jet catheter ventilation, migration of blood into the lower respiratory tract was seen when reflux of blood reached the entrainment area. From this area, blood is transported within the jet stream into the lower respiratory tract. CONCLUSIONS: SHFJV protects the lower respiratory tract from blood aspiration in case of tracheal bleeding. During SHFJV via the 4-lumen jet catheter, aspiration of blood only occurs if bleeding is localized cranial to the 4-lumen jet catheter ventilation. In case of heavy tracheal bleeding, the jet sources should be positioned cranial to the site of bleeding.

Emergency airway access in children--transtracheal cannulas and tracheotomy assessed in a porcine model.

OBJECTIVES: In the rare scenario when it is impossible to oxygenate or intubate a child, no evidence exists on what strategy to follow. AIM: The aim of this study was to compare the time and success rate when using two different transtracheal needle techniques and also to measure the success rate and time when performing an emergency tracheotomy in a piglet cadaver model. METHODS: In this randomized cross-over study, we included 32 anesthesiologists who each inserted two transtracheal cannulas (TTC) using a jet ventilation catheter and an intravenous catheter in a piglet model. Second, they performed an emergency tracheotomy. A maximum of 2 and 4 min were allowed for the procedures, respectively. The TTC procedures were recorded using a video scope. RESULTS: Placement of a transtracheal cannula was successful in 65.6% and 68.8% of the attempts (P = 0.76), and the median duration of the attempts was 69 and 42 s (P = 0.32), using the jet ventilation catheter and the intravenous catheter, respectively. Complications were frequent in both groups, especially perforation of the posterior tracheal wall. Performing an emergency tracheotomy was successful in 97%, in a median of 88 s. CONCLUSIONS: In a piglet model, we found no significant difference in success rates or time to insert a jet ventilation cannula or an intravenous catheter transtracheally, but the incidence of complications was high. In the same model, we found a 97% success rate for performing an emergency tracheotomy within 4 min with a low rate of complications.

Ventilation through a small-bore catheter: optimizing expiratory ventilation assistance.

BACKGROUND: Emergency ventilation through a small-bore transtracheal catheter can be lifesaving in a 'cannot intubate, cannot ventilate' situation. Ejectors, capable of creating suction by the Bernoulli principle, have been proposed to facilitate expiration through small-bore catheters. In this bench study, we compared a novel, purpose-built ventilation ejector (DE 5) with a previously proposed, modified industrial ejector (SBP 07). METHODS: The generated insufflation pressures, suction pressures in static and dynamic situations, and also suction capacities and entrainment ratios of the SBP 07 and the DE 5 were determined. The DE 5 was also tested in a lung simulator with a simulated complete upper airway obstruction. Inspiratory and expiratory times through a transtracheal catheter were measured at various flow rates and achievable minute volumes were calculated. RESULTS: In a static situation, the SBP 07 showed a more negative pressure build-up compared with the DE 5. However, in a dynamic situation, the DE 5 generated a more negative pressure, resulting in a higher suction capacity. Employment of the DE 5 at a flow rate of 18 litre min(-1) allowed a minute volume through the transtracheal catheter of up to 8.27 litre min(-1) at a compliance of 100 ml cm H(2)O(-1). The efficiency of the DE 5 depended on the flow rate of the driving gas and the compliance of the lung simulator. CONCLUSION: In laboratory tests, the DE 5 is an optimized ventilation ejector suitable for applying expiratory ventilation assistance. Further research may confirm the clinical applicability as a portable emergency ventilator for use with small-bore catheters.

The Veres adapter: clinical experience with a new device for jet ventilation via a laryngeal mask airway during flexible bronchoscopy.

BACKGROUND: A new device was developed to deliver high-frequency jet ventilation via a laryngeal mask airway (LMA). We investigated its use during flexible fiberoptic bronchoscopy in anesthetized patients. METHODS: Thirty adults were studied during interventional bronchoscopy. After facemask ventilation, the Veres adapter was connected to a size 4 or 5 LMA, and superimposed high-frequency jet ventilation was performed. Oxygen saturation, transcutaneous carbon dioxide, supraglottic airway pressure, and hemodynamic data were recorded and analyzed. RESULTS: Procedures were performed under stable hemodynamic conditions. Short procedure times and fast recovery were observed. Mild hypercapnia was the most common minor adverse effect (n = 16). One patient developed a pneumothorax after peripheral biopsy, 1 patient had a stiff chest during bronchoscopy, resulting in high airway pressures, and 1 patient required continuous positive airway pressure mask ventilation in the postoperative care unit. CONCLUSIONS: We report the clinical use of the Veres adapter in conjunction with an LMA to achieve rapid surgical access and adequate ventilation during flexible bronchoscopy. As an alternative to the use of an endotracheal tube, the new system may better maintain the airway during interventional and diagnostic bronchoscopy because of the larger diameter conduit.

[Anesthetic management in laryngotracheal surgery. High-frequency jet ventilation as strategy for ventilation during general anesthesia]. / Anästhesiologische Besonderheiten bei der laryngotrachealen Chirurgie.

During surgical procedures of the upper respiratory tract anesthesiologists and surgeons are in a kind of competition situation because of the close spatial relationship between the airway of the patient and the surgical area. Especially in laryngeal surgery the use of high-frequency jet ventilation (HFJV) offers an alternative to the endotracheal tube. 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. Severe tracheal stenosis, risk of excessive bleeding during the procedure, patients at risk for aspiration and exacerbation of lung diseases are depicted as contraindications for HFJV. Complications under HFJV are rare despite the limited conditions for monitoring gas exchange and mechanics of ventilation in contrast to conventional ventilation. A particular challenge for the anesthesiologist is the use of HFJV during laryngeal laser surgery.

Kinking of catheters during translaryngeal jet ventilation: a bench model investigation of eight devices.

OBJECTIVE: To evaluate oxygen flow through several transtracheal devices in native and right angle kinked states. MATERIAL AND METHOD: Eight catheter-over-needle, and two oxygen conveyance devices (Enk Flow Modulator 10 L/min flow and Manujet III Jet device 15, 30, 50 psi) were examined. Oxygen flow from each catheter was measured five times with three insufflation patterns [continuous insufflation, one second insufflation/one second pause (1:1), one second insufflation/three second pause (1:3)] in both native, and 90 degree kinked condition. RESULTS: During continuous insufflation, all but the 20G catheter delivered flows of more than 7 L/m with all conveyance pressures. With a 1:1 insufflation/pause ratio, catheters smaller than 16G were able to deliver 7 L/min flow only with driving pressures of 30 and 50 psi. With a 1:3 insufflation ratio, no catheter could deliver adequate flow with 15 psi (manujet) or with the Enk Flow modulator Only the Cook catheter and 14G Ravussin were capable at 30 psi. Only the Cook Transtracheal Jet Ventilation Catheter could deliver adequate flow in kinked position, but only at 50 psi. CONCLUSION: Needle-catheters designed for vascular access are marginally capable of effective TJV. The Cook Transtracheal Jet Ventilation catheter proved to be the most robust device in the kinked state, but only when combined with a high-pressure oxygen conveyance system.

Multi-Institutional Analysis of Outcomes in Supraglottic Jet Ventilation with a Team-Based Approach.

OBJECTIVES/HYPOTHESIS: To evaluate the safety and complications of endoscopic airway surgery using supraglottic jet ventilation with a team-based approach. STUDY DESIGN: Retrospective cohort study. METHODS: Subjects at two academic institutions diagnosed with laryngotracheal stenosis who underwent endoscopic airway surgery with jet ventilation between January 2008 and December 2018 were identified. Patient characteristics (age, gender, race, follow-up duration) and comorbidities were extracted from the electronic health record. Records were reviewed for treatment approach, intraoperative data, and complications (intraoperative, acute postoperative, and delayed postoperative). RESULTS: Eight hundred and ninety-four patient encounters from 371 patients were identified. Intraoperative complications (unplanned tracheotomy, profound or severe hypoxic events, barotrauma, laryngospasm) occurred in fewer than 1% of patient encounters. Acute postoperative complications (postoperative recovery unit [PACU] rapid response, PACU intubation, return to the emergency department [ED] within 24 hours of surgery) were rare, occurring in fewer than 3% of patient encounters. Delayed postoperative complications (return to the ED or admission for respiratory complaints within 30 days of surgery) occurred in fewer than 1% of patient encounters. Diabetes mellitus, active smoking, and history of previous tracheotomy were independently associated with intraoperative, acute, and delayed complications. CONCLUSIONS: Employing a team-based approach, jet ventilation during endoscopic airway surgery demonstrates a low rate of complications and provides for safe and successful surgery. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:2292-2297, 2021.

Achieving an adequate minute volume through a 2 mm transtracheal catheter in simulated upper airway obstruction using a modified industrial ejector.

BACKGROUND: Needle cricothyrotomy and subsequent transtracheal jet ventilation (TTJV) is one of the last options to restore oxygenation while managing an airway emergency. However, in cases of complete upper airway obstruction, conventional TTJV is ineffective and dangerous. We transformed a small, industrial ejector into a simple, manual ventilator providing expiratory ventilation assistance (EVA). METHODS: An ejector pump was modified to allow both insufflation of oxygen and jet-assisted expiration through an attached 75 mm long transtracheal catheter (TTC) with an inner diameter (ID) of 2 mm by alternately occluding and releasing the gas outlet of the ejector pump. In a lung simulator, the modified ejector pump was tested at different compliances and resistances. Inspiration and expiration times were measured and achievable minute volumes (MVs) were calculated to determine the effect of EVA. RESULTS: The modified ejector pump shortened the expiration time and an MV up to 6.6 litre min(-1) could be achieved through a 2 mm ID TTC in a simulated obstructed airway. CONCLUSIONS: The principle of ejector-based EVA seems promising and deserves further evaluation.

High-frequency jet ventilation as an alternative method compared to conventional one-lung ventilation using double-lumen tubes during minimally invasive coronary artery bypass graft surgery.

OBJECTIVE: To optimize the conditions for the surgeon during minimally invasive direct coronary artery bypass (MIDCAB) and totally endoscopic coronary artery bypass (TECAB) procedures, one-lung ventilation (OLV) is required using double-lumen tubes (DLT). This prospective study was designed to compare high-frequency jet ventilation (HFJV) of both lungs with the conventional method of OLV via DLT. DESIGN: Prospective, randomized, clinical study. SETTING: University-affiliated heart center. PARTICIPANTS: Forty patients with coronary artery disease and scheduled for elective MIDCAB or TECAB procedures were equally randomized into a DLT and an HFJV group. INTERVENTIONS: In the DLT group, OLV of the right lung was performed throughout the surgical procedure. In the HFJV group, patients received a conventional single-lumen endotracheal tube and both lungs were ventilated using HFJV. MEASUREMENTS: Hemodynamic, oxygenation and ventilation parameters were measured at the beginning of the operation, then 5, 15, 30, and 60 minutes after OLV/HFJV, as well as immediately before transfer to the ICU. MAIN RESULTS: Regarding the view of the surgical field, surgeons' comfort did not differ between methods. The intraoperative PaO(2) was significantly higher in the HFJV group compared with the DLT group at 5 (336.8 +/- 123.3 v 228.6 +/- 124.0; p = 0.009) and 15 minutes (301.7 +/- 133.9 v 192.6 +/- 92.8; p = 0.012). The PaCO(2) was significantly higher in the HFJV group after 5 minutes and persisted through 60 minutes of ventilation. The peak inspiratory pressure was significantly lower during HFJV (10.0 +/- 2.8 mbar v 32.1 +/- 5.9 mbar). CONCLUSIONS: HFJV in MIDCAB or TECAB procedures appears to be a feasible alternative to OLV using a DLT, although study in a larger population is required.