Airway obstruction and high-frequency jet ventilation during laryngoscopy

High Frequency Jet Ventilation or Mechanical Ventilation for Panendoscopy for Cervicofacial Cancer: A Retrospective Study

Introduction-the upper airway panendoscopy, performed under general anesthesia, is mandatory for the diagnosis of cervicofacial cancer. It is a challenging procedure because the anesthesiologist and the surgeon have to share the airway space together. There is no consensus about the ventilation strategy to adopt. Transtracheal high frequency jet ventilation (HFJV) is the traditional method in our institution. However, the COVID-19 pandemic forced us to change our practices because HFJV is a high risk for viral dissemination. Tracheal intubation and mechanical ventilation were recommended for all patients. Our retrospective study compares the two ventilation strategies for panendoscopy: high frequency jet ventilation (HFJV) and mechanical ventilation with orotracheal intubation (MVOI). Methods-we reviewed all panendoscopies performed before the pandemic in January and February 2020 (HFJV) and during the pandemic in April and May 2020 (MVOI). Minor patients, patients with a tracheotomy before or after, were excluded. We performed a multivariate analysis adjusted on unbalanced parameters between the two groups to compare the risk of desaturation. Results-we included 182 patients: 81 patients in the HFJV group and 80 in the MVOI group. After adjustments based on BMI, tumor localization, history of cervicofacial cancer surgery, and use of muscle relaxants, the patients from the HFJV group showed significantly less desaturation than the intubation group (9.9% vs. 17.5%, OR_a = 0.18, p = 0.047). Conclusion-HFJV limited the incidence of desaturation during upper airway panendoscopies in comparison to oral intubation.

A Resuscitation Option for Upper Airway Occlusion Based on Bolus Transtracheal Lung Inflation

Background

Acute laryngospasm sufficient to cause obstructive apnea is a medical emergency that can be difficult to manage within the very short time available for establishing an airway. We have presented substantial evidence that laryngospasm-based obstructive apnea is the cause of sudden death in epilepsy, and airway management is particularly challenging during seizure activity.

Objective

We sought to determine if the transtracheal delivery of a bolus of oxygen or room air below the level of an obstruction to inflate the lungs could be an effective method to prolong the time available for responders seeking to establish a stable airway, and, if so, what could be learned about optimization of delivery parameters from a rat model.

Methods

Rats were fitted with a t-shaped tracheal tube for controlling access to air and for measuring airway pressures. After respiratory arrest from simulated laryngospasm, bolus transtracheal lung inflation with a volume of gas equivalent to half the vital capacity was delivered to the closed respiratory system as the only resuscitation step.

Results

Bolus lung inflation was sufficient for resuscitation, improving cardiac function and re-establishing adequate oxygen status to support life. Inflation steps could be repeated and survival times were approximately 3 times that of non-inflated lungs.

Conclusion

The properties and consequences of bolus lung inflation are described as a foundation for procedures or devices that can be useful in cases of severe laryngospasm and other cases of upper airway obstruction.

Level of Evidence

3.

Interventional Pulmonology

Bronchoscopy presents a unique challenge and need for collaboration between anesthesia providers and bronchoscopists. The approach to topical anesthesia, analgesia, and sedation must be customized based on complexity, duration, and setting. The bronchoscopy team must work together in each phase of the procedure to ensure patient safety and allow completion of a quality bronchoscopy. Airway access may change depending on the type of procedure planned and must be discussed before each case. Intraprocedural difficulties with ventilation, airway pressure, and sedation may arise that must be addressed together. This review highlights an approach to these common challenges.

[16 years of experience in laryngeal microsurgery with use laser CO₂: cooperation between laryngologist and anesthesiologist - in material of ENT Department of Silesian Medical University]

Laryngeal microsurgery is currently the primary method of treatment of many diseases of the larynx. Breakthrough for the development of laryngeal microsurgery was the introduction of laser technology. The laryngeal microsurgery is used mainly laser CO₂. Endoscopic laryngeal microsurgery using the laser poses a unique challenge to the anesthesiologist, ensuring safe conditions of anesthesia, the patient and simultaneously appropriate operating conditions for the surgeon for precisely perform the procedure.

MATERIAL AND METHODS

Between 1995 and 2010 carried out in the Department of Otolaryngology SUM 832 microsurgical operations of the larynx using a CO₂ laser.

CONCLUSION

The perioperative management and close cooperation with the surgeon and anesthesiologist are essential for safe and efficient conduct of the operation the larynx using a microsurgical CO₂ laser.

Étude d'un respirateur de jet ventilation, le Mistral®, sur banc d'essai

OBJECTIVE

To test a high-frequency jet ventilator, the Mistral (Acutronic Laboratory) on a lung model.

METHODS

The jet ventilator Mistral was tested with two connectors (7 and 20 ml) and four catheters. Pressure and flow measurements were performed by varying the driving pressure (1 to 3 bars), the I/T ratio (0.25, 0.35, 0.45) and the frequency (1 to 5 Hz). Recorded data were: the volume delivered by the ventilator, the pressure measured in the connecting line between the ventilator and the injector and the difference between the end expiratory pressure measured by the ventilator through the injector and the tracheal pressure.

RESULTS

An increase in driving pressure induced a proportional increase in minute volume whatever the injection catheter used. After insufflation, when a Seldicath catheter was used, the pressure decrease was the slowest and the time constant the longest. Increase in frequency or I/T ratio, particularly beyond 0.35, was associated with an increase of the end expiratory pressure measured by the respirator. The gradient of pressure measured by the respirator and by an external sensor was lower with the 7 ml connector whatever the catheter used, and was larger with the Seldicath catheter.

CONCLUSION

The use of a low volume connector should be preferred, because it allows the measurement of the end expiratory pressure for a larger range of driving pressure, expiratory time and catheters. The performances of the Seldicath catheter are below those of the other catheters studied.

High-frequency jet ventilation in interventional bronchoscopy: factors with predictive value on high-frequency jet ventilation complications

STUDY OBJECTIVE

To evaluate the incidence and impact on clinical outcome of complications observed during high-frequency jet ventilation (HFJV) at interventional bronchoscopy and to identify the perioperative factors that may be associated to an increased incidence of such complications.

DESIGN

Observational retrospective, study with an observational prospective validation of the statistically significant associations.

SETTING

University hospital.

PATIENTS

The retrospective study involved 276 patients who underwent an interventional rigid bronchoscopy during general anesthesia and HFJV. Forty consecutive patients were accrued for the prospective validation group. INTERVENTIONS/MEASUREMENTS: Information recorded included patient medical history and perioperative complications observed at HFJV-managed bronchoscopic procedures and their impact on clinical outcome until hospital discharge.

MAIN RESULTS

At least one complication was detected in 38% of retrospective patients and 55% of prospective patients. Most frequent complications were hypercapnia, hypoxemia, and hemodynamic instability, but just one case of barotrauma in the retrospective group. Despite the high incidence, these complications were transient and did not increase hospital stay, whereas technical failure to widen airway lumen was associated with an adverse prognosis. Several clinical parameters showed a significant association with complications in the univariate analysis. However, the multivariate analysis only evidenced two independent predictive factors: the ASA physical status scale and baseline oxygen saturation.

CONCLUSIONS

Classification in ASA physical status IV group and a baseline oxygen saturation of 95% or less independently predicted the development of complications during interventional rigid bronchoscopy with HFJV.

[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.

Comparing methods of administering high-frequency jet ventilation in a model of laryngotracheal stenosis

We administered high-frequency jet ventilation (HFJV) to a tracheal-lung model with connectors of internal diameter 2.5-8.5 mm to simulate ventilation through varying degrees of laryngotracheal stenosis. With reductions in diameter, end-expiratory pressure (EEP) and peak inspiratory pressure (PIP) increased. During supraglottic, translaryngeal, and transtracheal HFJV, respectively, EEP was > or =10 mm Hg at diameters narrower than 5.5, 4.0, and 3.5 cm, and PIP was >20 mm Hg at diameters narrower than 5.5, 3.5, and 3.0 cm. EEP and PIP were greater during supraglottic HFJV than during translaryngeal and transtracheal HFJV (P < 0.01). At diameters of <3.5 and 4.0 cm, respectively, PIP and EEP increased and were significantly greater (P < 0.01) during translaryngeal HFJV than during transtracheal HFJV. In a second experiment, the degree of ventilation and air entrainment was assessed by administering nitrous oxide 4 L/min to the model. Nitrous oxide concentrations were significantly (P < 0.01) smaller and nitrogen concentrations were significantly (P < 0.01) larger during supraglottic HFJV than either translaryngeal or transtracheal HFJV. The larger EEP and PIP associated with supraglottic HFJV may be attributable to increased ventilation and air entrainment compared with translaryngeal and transtracheal HFJV.

IMPLICATIONS

Ventilatory driving pressure during supraglottic high-frequency jet ventilation may be reduced to minimize high airway pressures and hence the potential for pulmonary barotrauma in patients with laryngotracheal stenosis.

Transtracheal high frequency jet ventilation for endoscopic airway surgery: a multicentre study

Serious complications during high frequency jet ventilation (HFJV) are rare and have been documented in animals and in case reports or short series of patients with a difficult airway. We report complications of transtracheal HFFJV in a prospective multicentre study of 643 patients having laryngoscopy or laryngeal laser surgery. A transtracheal catheter could not be inserted in two patients (0.3%). Subcutaneous emphysema (8.4%) was more frequent after multiple tracheal punctures. There were seven pneumothoraces (1%), two after laser damage to the injector, one after difficult laryngoscopy, four with no clear cause. Arterial desaturation of oxygen was more frequent during laser surgery and in overweight patients. Transtracheal ventilation from a ventilator with an automatic cut-off device is a reliable method for experienced users. Control of airway pressure does not prevent a low frequency of pneumothorax.

Cricothyroidotomy and transtracheal high frequency jet ventilation for elective laryngeal surgery. An audit of 90 cases

We carried out an audit of needle cricothyroidotomy and transtracheal ventilation used during anaesthesia for elective endolaryngeal surgery. The data on 90 consecutive procedures was collected over two years. Patients were anaesthetized using a total intravenous technique. An intravenous cannula or Tuohy needle was placed through the cricothyroid membrane and the patient was ventilated via the cannula using high frequency jet ventilation. Technical details of the procedure and any perioperative complications were recorded. There were 12 complications in total. Only three of these were clearly related to the cricothyroid puncture, i.e., one minor bleed and two cases of limited local surgical emphysema. All complications were minor and resolved without sequelae.

Anesthesia for microlaryngeal surgery: the case for subglottic jet ventilation

Although the techniques for surgery on the endolarynx using suspension and the operating microscope have been fully developed, the safest, and least obtrusive anesthetic technique has yet to be manifested, as evidenced by more than 200 references to anesthesia for microlaryngoscopy in the world literature. This study reviews the physiology, physics, and problems of each anesthetic technique. In light of this review, animal and human studies are reported demonstrating the utility and safety of subglottic ventilation when provided with proper monitoring using an automatic ventilator. A modified Ben-Jet tube is reported, which has a 1-mm ID channel to monitor PCO2 and tracheal pressure. This self-centering 3.0-mm tube, which extends 6 to 8 cm below the glottis, is unobtrusive for the surgeon. The subglottic tube, which is much less likely to be malaligned, is much more acceptable to the anesthesiologist. Anesthesia, by intravenous sedation, utilizes neuromuscular blockade while ventilating through the jet tube powered by an automatic ventilator with an automatic shutdown feature attached to the monitor tube to prevent inadvertent barotrauma. The third phase of this study compared fluoroplastic, used in a prototype jet ventilation tube, with 6-mm Silastic, Red Rubber, and polyvinyl chloride (PVC) tubes when struck by maximum power of CO2, Nd-YAG, and K-532 lasers. The test was performed in a closed chamber in which concentrations of oxygen and nitrogen were controlled. Although damaged by the CO2 laser beam, the fluoroplastic tubes did not continue burning when the laser was turned off in 100% oxygen, even when coated by blood. The other three tubes continued to burn in 23% oxygen. Neither the KTP nor Nd-YAG laser damaged the Teflon tube, while they ignited a sustained flame in 30% oxygen. This study supports the use of fluoroplastic for a laser safe jet ventilation tube. It also demonstrates the danger of tube fires, even in low oxygen concentrations, when using Silastic, rubber, and PVC tubes in laser laryngeal surgery. There was no difference in the flammability of Silastic, rubber or PVC when struck by these lasers in this study. For these reasons, subglottic ventilation using a fluoroplastic, monitored, self-centering, subglottic, jet ventilation tube driven by an automatic ventilator with a shutdown feature, in the event of excessive pressure buildup, is proposed for anesthetizing healthy patients undergoing suspension microlaryngoscopy, and who have no airway obstructing lesion. A large tube with inflatable cuff is indicated when a supraglottic lesion may obstruct the airway.

High-frequency jet ventilation--a review of its role in laryngology

High-frequency jet ventilation (HFJV) is a safe, effective anaesthetic technique with a low risk of aspiration which has not yet gained wide acceptance in laryngology. Following anaesthesia and muscular relaxation the patient is intubated with a size 7FG infant feeding catheter and ventilation is achieved by delivering small bursts of anaesthetic gas at high frequency. The mechanisms of gas exchange are thought to be little different from those of conventional ventilation. We have found HFJV to be of value in laryngoscopy, laryngo-tracheal reconstruction, tracheoplasty, bronchoscopy and tonsillectomy. The advantages include: (a) ease of intubation, especially in the presence of a supraglottic mass; (b) improved surgical access compared with a conventional endotracheal tube; and (c) protection of the airway by the inherent 'auto-PEEP' effect. Care must be taken to ensure that conditions allow adequate exhaust of expired gas. Humidification of inspired gas is essential during prolonged procedures.

[Use of Diprivan in chronic respiratory insufficiency]

Propofol may be recommended as an anaesthetic agent in patients with chronic respiratory insufficiency since: it prevents the increase in bronchial resistances resulting from the administration of opioids; it possesses a bronchodilator effect, comparable with that of flunitrazepam; it ensures rapid recovery, which would favour patient's co-operation postoperatively. The effects of propofol on respiratory drive should not be neglected, as they may persist even after complete recovery. In pulmonary surgery, propofol may be recommended in patients with one-lung ventilation, since it does not depress the hypoxic vasoconstriction reflex. Some procedures may be carried out in spontaneous ventilation or, preferably, using jet ventilation, provided that propofol is given by means of an infusion pump.