Influence of Tracheal Obstruction on the Efficacy of Superimposed High-frequency Jet Ventilation and Single-frequency Jet Ventilation

Effectiveness and Safety of Superimposed High-Frequency Jet Ventilation in Rigid Bronchoscopy: A Single-Center, Retrospective Study

Introduction: Superimposed high-frequency jet ventilation (SHFJV) is a new type of jet ventilation, but its safety and effectiveness in rigid bronchoscopy have not been fully verified, especially in patients with airway stenosis and preoperative cardiovascular disease. This study is intended to retrospectively analyze the effectiveness and safety of SHFJV in the endobronchial treatment under rigid bronchoscopy. Methods: A total of 363 patients were included in this study. They were divided into 2 groups: Group A (n = 176)-presence of airway stenosis; Group B (n = 187)-absence of airway stenosis. Mean arterial pressure, heart rate, and pulse oxygen saturation were recorded before anesthesia and during the procedure. Arterial blood gases was recorded before anesthesia, at the end of the procedure and second-day postoperation respectively. The duration of procedure, extubation time, length of stay in the postanesthesia care unit (PACU), length of postoperative hospitalization, incidence of intraoperative and postoperative complications as well as 30 day mortality were also recorded. Results: All the patients had stable circulation during the procedure, including that with preoperative cardiovascular and pulmonary diseases. There were no substantial differences observed in terms of extubation time, PACU stay, and postoperative hospital days. Patients with severe preoperative airway stenosis exhibited longer procedure duration compared to those with mild to moderate stenosis, but there was no difference noted in terms of the extubation and PACU time. Conclusion: SHFJV is effective and safe in the endobronchial treatment for patients with airway stenosis and preoperative cardiovascular disease. It can serve as an ideal airway management strategy for rigid bronchoscopy.

Clinical study of multifunctional laryngeal mask in airway interventional therapy

OBJECTIVE

This study is conducted to evaluate the efficacy and safety of using multifunctional intubation laryngeal masks with normal frequency jet ventilation in airway interventional therapy.

METHODS

A total of 200 patients receiving airway interventional therapy were enrolled in this retrospective study and were divided into 2 groups (group M and group P) by doctors in our hospital to compare the effect of different laryngeal masks. Group M used common laryngeal masks and an anesthesia machine for positive pressure ventilation while group P took multifunctional intubation laryngeal masks and used a jet ventilator for normal frequency jet ventilation. The patients' mean arterial pressure, heart rate, arterial oxygen partial pressure (PaO2) and arterial carbon dioxide partial pressure (PaCO2), and the operation time, recovery score and the patients' and doctors' satisfaction levels were compared between the 2 groups.

RESULTS

Both groups were hemodynamically stable, and their PaO2 levels were significantly higher before the operation than that during and after the operation (P < .05). Compared with group M, the PaCO2 level of group P was more stable both during and after the operation, and this difference was statistically significant (P < .05). There was no statistically significant difference in terms of the 2 group's operating time, recovery score, and patients' satisfaction levels (P > .05). However, the satisfaction levels of doctors in group P were higher than that in group M, and this difference was statistically significant (P < .05).

CONCLUSION

As statistics show, the intraoperative hemodynamics and PaO2 and PaCO2 levels were stable, and patients, surgeons and anesthesia operators were satisfied. Therefore, it is feasible to apply multifunctional intubation laryngeal masks with normal frequency jet ventilation in airway interventional therapy and it is a safe and ideal way to ensure ventilation.

A multi-centre prospective random control study of superimposed high-frequency jet ventilation and conventional jet ventilation for interventional bronchoscopy

Introduction: Superimposed high-frequency jet ventilation (SHFJV) is a new type of jet ventilation that simultaneously uses high- and low-frequency types of jet ventilation. We compared SHFJV with the conventional high-frequency jet ventilation (CHFJV) in interventional bronchoscopy in terms of safety and effectiveness. Methods: A multi-centre prospective random single-blind clinical trial was conducted by three interventional bronchoscopy centres. Patients who underwent diagnostic or therapeutic bronchoscopy under general anaesthesia were admitted and divided into two groups: SHFJV group (trial group) and CHFJV group (control group). PaO2 and PaCO2 were recorded before anaesthesia and during and after the procedure. SpO2 and etCO2 were recorded every 10 min throughout the procedure. Patients were observed until 24 h post-bronchoscopy. Results: Sixty patients were included in the study. Twenty-nine were in the trial group, and 31 were in the control group. Both groups had no significant differences in demographic data. In the control group, the PaO2 measured in the operation was higher than that in the trial group (p = 0.023). The values of etCO2 in the control group were more dispersed than those of the trial group. When the procedure time was over 90 minutes, the etCO2 in the control group significantly increased (p = 0.01), while the etCO2 in trial group remained stable (p = 0.594). There were more patients with PaCO2 ≥ 50 mmHg during the procedure in the control group than in the trial group (p = 0.042). Conclusion: SHFJV is effective and safe in interventional bronchoscopy. It may provide more effective and stabilised ventilation than CHFJV in cases with long procedure times.

Safety application of muscle relaxants and the traditional low-frequency ventilation during the flexible or rigid bronchoscopy in patients with central airway obstruction: a retrospective observational study

Background

Bronchoscopy treatments of central airway obstruction (CAO) under general anesthesia are high-risky procedures, and posing a giant challenge to the anesthesiologists. We summarized and analyzed our clinical experience in patients with CAO undergoing flexible or rigid bronchoscopy, to estimate the safety of skeletal muscle relaxants application and the traditional Low-frequency ventilation.

Methods

Clinical data of 375 patients with CAO who underwent urgent endoscopic treatments in general anesthesia from January 2016 to October 2019 were retrospectively reviewed. The use ratio of skeletal muscle relaxants, dose of skeletal muscle relaxants used, the incidence of perioperative adverse events, adequacy of ventilation and gas exchange, post-operative recovery between rigid bronchoscopy and flexible bronchoscopy therapy, and risk factors for postoperative ICU admission were evaluated.

Results

Of the 375 patients with CAO, 204 patients were treated with flexible bronchoscopy and 171 patients were treated with rigid bronchoscopy. Muscle relaxants were used in 362 of 375 patients (including 313 cisatracurium, 45 rocuronium, 4 atracurium, and 13 unrecorded). The usage rate of muscle relaxants (96.5% in total) was very high in patients with CAO who underwent either flexible bronchoscopy (96.6%) or rigid bronchoscopy (96.5%) therapy. The dosage of skeletal muscle relaxants (Cisatracium) used was higher in rigid bronchoscopy compared with flexible bronchoscopy therapy (10.8 ± 3.8 VS 11.6 ± 3.6 mg, respectively, p < 0.05). No patient suffered the failure of ventilation, bronchospasm and intraoperative cough either in flexible or rigid bronchoscopy therapy. Hypoxemia was occurred in 13 patients (8 in flexible, 5 in rigid bronchoscopy) during the procedure, and reintubation after extubation happened in 2 patients with flexible bronchoscopy. Sufficient ventilation was successfully established using the traditional Low-frequency ventilation with no significant carbon dioxide accumulation and hypoxemia occurred both in flexible and rigid bronchoscopy group (p > 0.05). Three patients (1 in flexible and 2 in rigid) died, during the post-operative recovery, and the higher grade of American Society of Anesthesiologists (ASA) and obvious dyspnea or orthopnea were the independent risk factors for postoperative ICU admission.

Conclusion

The muscle relaxants and low-frequency traditional ventilation can be safely used both in flexible and rigid bronchoscopy treatments in patients with CAO. These results may provide strong clinical evidence for optimizing the anesthesia management of bronchoscopy for these patients.

Physiological changes and compensatory mechanisms by the action of respiratory muscles in a porcine model of phrenic nerve injury

Phrenic nerve damage may occur as a complication of specific surgical procedures, prolonged mechanical ventilation, or physical trauma. The consequent diaphragmatic paralysis or dysfunction can lead to major complications. The purpose of this study was to elucidate the role of the nondiaphragmatic respiratory muscles during partial or complete diaphragm paralysis induced by unilateral and bilateral phrenic nerve damage at different levels of ventilatory pressure support in an animal model. Ten pigs were instrumented, the phrenic nerve was exposed from the neck, and spontaneous respiration was preserved at three levels of pressure support, namely, high, low, and null, at baseline condition, after left phrenic nerve damage, and after bilateral phrenic nerve damage. Breathing pattern, thoracoabdominal volumes and asynchrony, and pressures were measured at each condition. Physiological breathing was predominantly diaphragmatic and homogeneously distributed between right and left sides. After unilateral damage, the paralyzed hemidiaphragm was passively dragged by the ipsilateral rib cage muscles and the contralateral hemidiaphragm. After bilateral damage, the drive to and the work of breathing of rib cage and abdominal muscles increased, to compensate for diaphragmatic paralysis, ensuing paradoxical thoracoabdominal breathing. Increasing level of pressure support ventilation replaces this muscle group compensation. When the diaphragm is paralyzed (unilaterally and/or bilaterally), there is a coordinated reorganization of nondiaphragmatic respiratory muscles as compensation that might be obscured by high level of pressure support ventilation. Noninvasive thoracoabdominal volume and asynchrony assessment could be useful in phrenic nerve-injured patients to estimate the extent and type of inspiratory muscle dysfunction.NEW & NOTEWORTHY This was the first (to our knowledge) implanted porcine model of phrenic nerve injury with a detailed multidimensional analysis of different degrees of diaphragmatic paralysis (unilateral and bilateral). Noninvasive thoracoabdominal volume and asynchrony assessment was shown to be useful in estimating the extent of diaphragmatic dysfunction and the consequent coordinated reorganization of nondiaphragmatic respiratory muscles. High level of pressure support ventilation was proved to obscure the interaction and compensation of respiratory muscles to deal with phrenic nerve injury.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Effect of Increased Body Mass Index on Complication Rates during Laryngotracheal Surgery Utilizing Jet Ventilation

Objective Jet ventilation has been used for >30 years as an anesthetic modality for laryngotracheal surgery. Concerns exist over increased risk with elevated body mass index (BMI). We reviewed our experience using jet ventilation for laryngotracheal stenosis to assess for complication rates with substratification by BMI. Study Design Case series with chart review. Setting Tertiary care center. Subjects and Methods A total of 126 procedures with jet ventilation were identified from October 2006 to December 2014. Complications were recorded, including intubation, unplanned admission, readmission, dysphonia, oral trauma, pneumothorax, pneumomediastinum, and tracheostomy. Lowest intraoperative oxygen saturation and maximum end-tidal CO₂ (ETCO₂) levels were recorded. Results Among 126 patients, 43, 77, and 6 had BMIs of <25, 25-35, and 36-45, respectively. In the BMI <25 group, there was 1 unplanned intubation. Mean maximum ETCO₂ was 36.51 with no hypoxemia observed. In the BMI 25-35 group, 2 patients required intubation, and 1 sustained minor oral trauma. The mean maximum ETCO₂ was 38.85, with 4 patients having oxygen saturation <90%. In the BMI 36-45 group, 2 patients required intubation. The mean maximum ETCO₂ was 41 with no hypoxemia observed. BMI and length of stenosis were statistically significant variables associated with incidence of intraoperative intubation. Conclusion Increased BMI was associated with an increase in highest ETCO₂ intraoperatively. However, this was not associated with an increase in major complications. Jet ventilation was performed without significant adverse events in this sample, and it is a viable option if used with an experienced team in the management of laryngotracheal stenosis.

Jet Ventilation during Rigid Bronchoscopy in Adults: A Focused Review

The indications for rigid bronchoscopy for interventional pulmonology have increased and include stent placements and transbronchial cryobiopsy procedures. The shared airway between anesthesiologist and pulmonologist and the open airway system, requiring specific ventilation techniques such as jet ventilation, need a good understanding of the procedure to reduce potentially harmful complications. Appropriate adjustment of the ventilator settings including pause pressure and peak inspiratory pressure reduces the risk of barotrauma. High frequency jet ventilation allows adequate oxygenation and carbon dioxide removal even in cases of tracheal stenosis up to frequencies of around 150 min⁻¹; however, in an in vivo animal model, high frequency jet ventilation along with normal frequency jet ventilation (superimposed high frequency jet ventilation) has been shown to improve oxygenation by increasing lung volume and carbon dioxide removal by increasing tidal volume across a large spectrum of frequencies without increasing barotrauma. General anesthesia with a continuous, intravenous, short-acting agent is safe and effective during rigid bronchoscopy procedures.