Video double-lumen tube for one lung ventilation: implementation and experience in 343 cases of routine clinical use during the first 20 months of the SARS-CoV-2 pandemic.

BACKGROUND: Double-lumen tubes (DLTs) are the preferred device for lung isolation. Conventional DLTs (cDLT) need a bronchoscopic position control. Visualisation of correct DLT positioning could be facilitated by the use of a video double-lumen tube (vDLT). During the SARS-CoV-2-pandemic, avoiding aerosol-generation was suggesting using this device. In a large retrospective series, we report both general and pandemic related experiences with the device. METHODS: All anesthesia records from patients aged 18 years or older undergoing surgery from April 1st, 2020 to December 31st, 2021 in the department of thoracic surgery requiring intraoperative lung isolation were analyzed retrospectively. RESULTS: During the investigation period 343 left-sided vDLTs (77.4%) and 100 left-sided cDLTs (22.6%) were used for one lung ventilation. In the vDLT group bronchoscopy could be reduced by 85.4% related to the cDLT group. Additional bronchoscopy to reach or maintain correct position was needed in 11% of the cases. Other bronchoscopy indications occured in 3.6% of the cases. With cDLT, in 1% bronchoscopy for other indications than conforming position was observed. CONCLUSIONS: The Ambu® VivaSight™ vDLT is an efficient, easy-to-use and safe airway device for the generation of one lung ventilation in patients undergoing thoracic surgery. The vDLT implementation was achieved easily with full interchangeability to the left-sided cDLT. Using the vDLT can reduce the need for aerosol-generating bronchoscopic interventions by 85.4%. Continuous video view to the carina enabling position monitoring of the DLT without need for bronchoscopy might be beneficial for both employee's and patient's safety.

Managing One-Lung Ventilation in Tracheostomized Patients: A 6-Year Retrospective Analysis.

BACKGROUND: To ensure safe and optimal surgical conditions in thoracic surgery, one-lung ventilation is crucial. Various techniques exist to achieve one-lung ventilation. Tracheotomized patients who require one-lung ventilation represent a unique and rare subgroup that demands specialized knowledge and skills. The very limited literature has discussed alternative methods, no randomized controlled trials have addressed this issue yet. METHODS: We performed a retrospective analysis of patients who underwent one-lung ventilation in the Department of Thoracic Surgery of a German University Hospital between 2016 and 2021. The study assessed patient demographics, airway management techniques, ventilation parameters, and adverse events. RESULTS: In 3,197 anesthesia procedures during the observation period, 152 patients had an existing tracheostomy, of which 56 required one-lung ventilation. Among others in 42 cases, a tracheostomy tube was combined with a bronchial blocker, and in 10 cases, a double-lumen tracheostomy tube was used. There were no severe complications. Intraoperative dislocations that required repositioning of the device occurred in six patients (13.3%) with bronchial blockers and one patient with double-lumen tracheostomy tube (10%). CONCLUSION: The management of one-lung ventilation in tracheotomized patients presents unique challenges. While double-lumen tracheostomy tubes have specific advantages, we recommend considering their use carefully. For most tracheotomized patients, bronchial blockers in conjunction with a tracheostomy tube are used, which offers safety and practicality, irrespective of the tracheostomy's age or type. Further research and randomized controlled trials are warranted to establish best practices for one-lung ventilation in this unique patient population.

Airway management in a two-year-old child with a tongue tumor using video laryngoscope-assisted flexible bronchoscopic nasotracheal intubation (hybrid technique).

Airway management in children can be challenging. A hybrid technique using a video laryngoscope-assisted flexible bronchoscopic nasotracheal intubation allowed a successful airway management in a two-year-old child with a large tongue tumor.

An approach to difficult airway in infants: Comparison of GlideScope® Spectrum LoPro, GlideScope® Spectrum Miller and conventional Macintosh and Miller blades in a simulated Pierre Robin sequence performed by 90 anesthesiologists.

BACKGROUND: Airway management can be challenging in neonates and infants. The Pierre Robin sequence (PRS) is a condition characterized by micrognathia, glossoptosis and airway obstruction. The airway management of these patients poses great challenges for anesthesiologists and pediatricians alike. To date, there has been no direct comparison of the hyperangulated GlideScope® Spectrum LoPro (GLP), the straight GlideScope® Spectrum Miller (GSM), a conventional Macintosh (MC) and a conventional Miller blade (ML) in patients with PRS. METHODS: For this purpose, 90 anesthesiologists (43 with limited experience, 47 with extensive experience) performed orotracheal intubation on an Air-Sim® Pierre Robin X manikin using GLP, GSM, MC and ML in randomized order. 'Time-to-vocal-cords', 'time-to-intubate', 'time-to-ventilate', the severity of oral-soft-tissue-trauma and the subjective evaluation of each device were recorded. RESULTS: A significantly faster and better view of the vocal cords and lower oral-soft-tissue-trauma was achieved using the GLP (p<0.001). Though, there were no significant differences in the 'time-to-intubate' or 'time-to-ventilate'. The highest intubation success rate was found with GSM and the lowest with GLP (GSM 100%, ML 97.8%, MC 96.7%, GLP 93.3%). When using the videolaryngoscopes, there were no undetected esophageal intubations but in six cases prolonged attempts of intubation (>120s) with the GLP. In the sub-group with extensive experience, we found significantly shorter intubation times for the GSM and ML. The GLP was the tool of choice for most participants, while the conventional MC received the lowest rating. CONCLUSIONS: Videolaryngoscopy leads to increased safety for the prevention of undetected esophageal intubation in the airway management in a PRS manikin. Hyperangulated blades may ensure a good and fast view of the vocal cords and low oral-soft-tissue-trauma but pose a challenge during the placement of the tube. Specific skills and handling seem to be necessary to ensure a safe tube placement with this sort of blades.

Comparison of Glidescope Core, C-MAC Miller and conventional Miller laryngoscope for difficult airway management by anesthetists with limited and extensive experience in a simulated Pierre Robin sequence: A randomized crossover manikin study.

BACKGROUND: Video laryngoscopy is an effective tool in the management of difficult pediatric airway. However, evidence to guide the choice of the most appropriate video laryngoscope (VL) for airway management in pediatric patients with Pierre Robin syndrome (PRS) is insufficient. Therefore, the aim of this study was to compare the efficacy of the Glidescope® Core™ with a hyperangulated blade, the C-MAC® with a nonangulated Miller blade (C-MAC® Miller) and a conventional Miller laryngoscope when used by anesthetists with limited and extensive experience in simulated Pierre Robin sequence. METHODS: Forty-three anesthetists with limited experience and forty-three anesthetists with extensive experience participated in our randomized crossover manikin trial. Each performed endotracheal intubation with the Glidescope® Core™ with a hyperangulated blade, the C-MAC® with a Miller blade and the conventional Miller laryngoscope. "Time to intubate" was the primary endpoint. Secondary endpoints were "time to vocal cords", "time to ventilate", overall success rate, number of intubation attempts and optimization maneuvers, Cormack-Lehane score, severity of dental trauma and subjective impressions. RESULTS: Both hyperangulated and nonangulated VLs provided superior intubation conditions. The Glidescope® Core™ enabled the best glottic view, caused the least dental trauma and significantly decreased the "time to vocal cords". However, the failure rate of intubation was 14% with the Glidescope® Core™, 4.7% with the Miller laryngoscope and only 2.3% with the C-MAC® Miller when used by anesthetists with extensive previous experience. In addition, the "time to intubate", the "time to ventilate" and the number of optimization maneuvers were significantly increased using the Glidescope® Core™. In the hands of anesthetists with limited previous experience, the failure rate was 11.6% with the Glidescope® Core™ and 7% with the Miller laryngoscope. Using the C-MAC® Miller, the overall success rate increased to 100%. No differences in the "time to intubate" or "time to ventilate" were observed. CONCLUSIONS: The nonangulated C-MAC® Miller facilitated correct placement of the endotracheal tube and showed the highest overall success rate. Our results therefore suggest that the C-MAC® Miller could be beneficial and may contribute to increased safety in the airway management of infants with PRS when used by anesthetists with limited and extensive experience.

Comparison of Glidescope® Go™, King Vision™, Dahlhausen VL, I­View™ and Macintosh laryngoscope use during difficult airway management simulation by experienced and inexperienced emergency medical staff: A randomized crossover manikin study.

BACKGROUND: In pre-hospital emergency care, video laryngoscopes (VLs) with disposable blades are preferably used due to hygienic reasons. However, there is limited existing data on the use of VLs with disposable blades by emergency medical staff. Therefore, the aim of this study was to compare the efficacy of four different VLs with disposable blades and the conventional standard Macintosh laryngoscope, when used by anesthetists with extensive previous experience and paramedics with little previous experience in endotracheal intubation (ETI) in a simulated difficult airway. METHODS: Fifty-eight anesthetists and fifty-four paramedics participated in our randomized crossover manikin trial. Each performed ETI with the new Glidescope® Go™, the Dahlhausen VL, the King Vision™, the I-View™ and the Macintosh laryngoscope. "Time to intubate" was the primary endpoint. Secondary endpoints were "time to vocal cords", "time to ventilate", overall success rate, number of intubation attempts and optimization maneuvers, Cormack-Lehane score, severity of dental compression and subjective impressions. RESULTS: The Glidescope® Go™, the Dahlhausen VL and the King Vision™ provided superior intubation conditions in both groups without affecting the number of intubation attempts or the time required for successful intubation. When used by anesthetists with extensive experience in ETI, the use of VLs did not affect the overall success rate. In the hands of paramedics with little previous experience in ETI, the failure rate with the Macintosh laryngoscope (14.8%) decreased to 3.7% using the Glidescope® Go™ and the Dahlhausen VL. Despite the advantages of hyperangulated video laryngoscopes, the I-View™ performed worst. CONCLUSIONS: VLs with hyperangulated blades facilitated ETI in both groups and decreased the failure rate by an absolute 11.1% when used by paramedics with little previous experience in ETI. Our results therefore suggest that hyperangulated VLs could be beneficial and might be the method of choice in comparable settings, especially for emergency medical staff with less experience in ETI.

Combined recurrent laryngeal nerve monitoring and one-lung ventilation using the EZ-Blocker and an electromyographic endotracheal tube.

BACKGROUND: Intraoperative neuromuscular monitoring (IONM) is a widespread procedure to identify and protect the recurrent laryngeal nerve (RLN) during thyroid surgery. However, for left thoracic surgery with high risk of RLN injury, both reliable recurrent laryngeal nerve monitoring and one-lung ventilation could interfere. METHODS: In this prospective study, a new method for IONM during one-lung ventilation combining RLN monitoring with an electromyographic (EMG) endotracheal tube (ETT) and lung separation using the EZ-Blocker (EZB) is described and its clinical feasibility and effectiveness were assessed. RESULTS: A total of 14 patients undergoing left upper lobe surgery and left upper mediastinal lymph node dissection were enrolled. The EZB was introduced and positioned without any problems and sufficient lung collapse was achieved in all patients. No tracheobronchial injuries or immediate complications occurred. A stable EMG signal was present in all patients and no RLN palsy and no negative side effects of the NIM EMG ETT or the EZB were observed postoperatively. CONCLUSIONS: The described method is technically feasible, easy to apply and save. It provides both reliable IONM and independent lung separation for optimal surgical exposure. The combined use of the EZB and the NIM EMG ETT might reduce the risk for RLN palsy and impaired lung separation during left thoracic surgery with high risk for RLN injury.

The EZ-blocker for one-lung ventilation in patients undergoing thoracic surgery: clinical applications and experience in 100 cases in a routine clinical setting.

BACKGROUND: In certain clinical situations the insertion of a double-lumen tube (DLT) for one-lung ventilation (OLV) is not feasible or unfavorable. In these cases, the EZ-Blocker (EZB) may serve as an alternative. The aim of our analysis was to report on the clinical applications and our experience with the EZB for one-lung ventilation in 100 patients undergoing thoracic surgery. METHODS: All anesthetic records from patients older than 18 years of age undergoing general anesthesia in the department of thoracic surgery with intraoperative use of an EZB for OLV at the University Hospital of Erlangen in four consecutive years were analyzed retrospectively. RESULTS: Most frequently, EZB was used in difficult airway (27%) and for surgical procedures with high risk for left recurrent laryngeal nerve injury (21%), followed by application in intubated (12%) or tracheostomized (11%) patients. 11% of the patients had an increased risk of gastric regurgitation. Almost all EZBs were placed free of complications (99%). Clinically sufficient lung collapse was achieved in all patients. No serious airway injuries or immediate complications were documented. CONCLUSIONS: The EZB is an efficient, easy-to-use and safe airway device and enables OLV in several clinical situations, when conventional DLTs are not feasible or less favorable. Three major applications were depicted from the data: expected difficult airway, surgical procedures with necessity of intraoperative recurrent laryngeal nerve monitoring and already intubated or tracheostomized patients.

Comparison of Metal and Plastic Disposable Laryngoscope Blade with Reusable Macintosh Blade in Difficult and Inhalation Injury Airway Scenario: A Manikin Study.

BACKGROUND: Single-use plastic blades (SUPB) and single-use metal blades (SUMB) for direct laryngoscopy and tracheal intubation have not yet been compared with reusable metal blades (RUMB) in difficult airway scenarios. OBJECTIVE: The purpose of our manikin study was to compare the effectiveness of these different laryngoscope blades in a difficult airway scenario, as well as in a difficult airway scenario with simulated severe inhalation injury. METHODS: Thirty anesthetists performed tracheal intubation (TI) with each of the three laryngoscope blades in the two scenario manikins. RESULTS: In the inhalation injury scenario, SUPB were associated with prolonged intubation times when compared with the metal blades. In the inhalation injury scenario, both metal laryngoscope blades provided a quicker, easier, and safer TI. In the difficult airway scenario, intubation times were significantly prolonged in the SUPB group in comparison to the RUMB group, but there were no significant differences between the SUPB and the SUMB. In this scenario, the RUMB demonstrated the shortest intubation times and seems to be the most effective device. CONCLUSIONS: Generally, results are in line with previous studies showing significant disadvantages of SUPB in both manikin scenarios. Therefore, metal blades might be beneficial, especially in the airway management of patients with inhalation injury.

Adverse airway events in parturient compared with non-parturient patients. Is there a difference? Results from a quality management project.

AIM: The fear of airway problems often leads to prolonged attempts to obtain neuroaxial (spinal anesthesia or epidural anesthesia) anesthesia in obstetric anesthesia. The aim of this institutional quality management study was to revisit existing anesthesia care in the obstetric department, focusing on the frequency of delayed or failed neuroaxial anesthesia as well as the risk of airway problems in parturient and non-obstetric patients. METHODS: The clinical records from 8 consecutive years (2005-2013) were analyzed retrospectively. Cases of cesarean delivery with general anesthesia were analyzed and compared with an age-matched group of female patients undergoing non-obstetric abdominal or gynecological surgery with rapid sequence induction. Poor laryngeal visualization (Cormack-Lehane grade III or IV) and failed intubation were recorded. RESULTS: The records of 6393 cesarean deliveries including 851 with general anesthesia were analyzed. In 175 cases insufficient or delayed onset of regional anesthesia led to requirement for general anesthesia. The rate of poor laryngoscopic view in parturient women undergoing cesarean delivery was 14/851, and 4/814 in the reference group (P = 0.023). Failed intubation occurred in three patients undergoing cesarean delivery (0.4%) and in one non-obstetric patient (0.1%; P = 0.339). CONCLUSION: The rate of failed intubations in patients undergoing cesarean delivery may be equivalent to non-obstetric patients. In time-challenging cesarean deliveries, delay of conversion from non-successful neuroaxial anesthesia to general anesthesia in order to avoid adverse airway events does not appear to be justified.

Incidence and predictors of poor laryngoscopic view in children undergoing pediatric cardiac surgery.

OBJECTIVE: Previous investigations reported a higher incidence of poor laryngoscopic views in pediatric patients undergoing cardiac surgery. The objective of this study was to analyze why children undergoing cardiac surgery have such an increased incidence of poor laryngoscopic views during anesthesia induction. DESIGN: This study was designed as a retrospective analysis. SETTING: This analysis was based on a single-center cohort of a university hospital. PARTICIPANTS: One thousand one hundred seventy-seven general anesthesia procedures, including a direct laryngoscopic view over a period of 6 consecutive years, in pediatric patients undergoing cardiac surgery. INTERVENTIONS: Because of the retrospective character of this study, there were no study-related interventions. MEASUREMENTS AND MAIN RESULTS: Poor laryngoscopic views were defined as Cormack and Lehane (CML) grade III and IV. The overall incidence of poor laryngoscopic views was 3.5%. In patients younger than 1 year of age, the incidence of CML III or IV was significantly higher than in the older patients (5.6% v 1.7%). None of the patients with CML III/IV findings had Down syndrome; whereas in 9 of 41 patients with CML grade III/IV, a concomitant congenital syndrome like DiGeorge syndrome or CHARGE syndrome was found. CONCLUSIONS: The general incidence of CML III/IV findings during the induction of anesthesia for pediatric cardiac surgery is more than twice as high as reported in unselected pediatric cohorts. In patients below 1 year of age and in male patients, difficult laryngoscopy is more frequent. Concomitant Down syndrome was not associated with difficult laryngoscopy.

Incidence and predictors of difficult laryngoscopy in 11,219 pediatric anesthesia procedures.

OBJECTIVE: Difficult laryngoscopy in pediatric patients undergoing anesthesia. AIM: This retrospective analysis was conducted to investigate incidence and predictors of difficult laryngoscopy in a large cohort of pediatric patients receiving general anesthesia with endotracheal intubation. BACKGROUND: Young age and craniofacial dysmorphy are predictors for the difficult pediatric airway and difficult laryngoscopy. For difficult laryngoscopy, other general predictors are not yet described. METHODS: Retrospectively, from a 5-year period, data from 11.219 general anesthesia procedures in pediatric patients with endotracheal intubation using age-adapted Macintosh blades in a single center (university hospital) were analyzed statistically. RESULTS: The overall incidence of difficult laryngoscopy [Cormack and Lehane (CML) grade III and IV] was 1.35%. In patients younger than 1 year, the incidence of CML III or IV was significantly higher than in the older patients (4.7% vs 0.7%). ASA Physical Status III and IV, a higher Mallampati Score (III and IV) and a low BMI were all associated (P < 0.05) with difficult laryngoscopy. Patients undergoing oromaxillofacial surgery and cardiac surgery showed a significantly higher rate of CML III/IV findings. CONCLUSION: The general incidence of difficult laryngoscopy in pediatric anesthesia is lower than in adults. Our results show that the risk of difficult laryngoscopy is much higher in patients below 1 year of age, in underweight patients and in ASA III and IV patients. The underlying disease might also contribute to the risk. If the Mallampati score could be obtained, prediction of difficult laryngoscopy seems to be reliable. Our data support the existing recommendations for a specialized anesthesiological team to provide safe anesthesia for infants and neonates.

Laryngeal morbidity after intubation with or without neuromuscular block in thyroid surgery using recurrent laryngeal nerve monitoring.

OBJECTIVE: The avoidance of neuromuscular blocking agents (NMBA) for endotracheal intubation is associated with a higher incidence of laryngeal discomfort and lesions, but could impair effectiveness of intra operative recurrent laryngeal nerve monitoring (IONM). METHODS: In a retrospective quality assessment study over a period of 30 months, a collective that had been intubated without NMBA was compared with a group, which had received NMBA. Endolaryngeal EMG was accomplished with a MagStim(®)-EMG-electrode. RESULTS: Out of the 127 patients with 224 nerves at risk (NAR; NMBA 102 NAR, no NMBA 122 NAR), more than 90% received a total intravenous anaesthesia with propofol, and 88% had remifentanil. Laryngeal side effects and damage scores did not differ significantly. CONCLUSIONS: In this special setting of IONM and thyroid surgery, avoidance of NMBA for endotracheal intubation seems not to increase the incidence of laryngeal side effects and lesions. If endotracheal intubation without NMBA is required, the authors suggest a standardized approach using induction agents as propofol and remifentanil.

Comparison of two electromyographical endotracheal tube systems for intraoperative recurrent laryngeal nerve monitoring: reliability and side effects.

BACKGROUND: Recurrent laryngeal nerve (RLN) monitoring systems should be reliable and safe. Monitoring via electromyographical systems on an endotracheal tube (ETT) is widely spread. The MagStim™ system consists of an adhesive electrode to be fixed on an endotracheal tube. The Xomed™ endotracheal tube provides integrated electrodes. Reliability and side effects had never been compared. As both systems have very different morphological properties, we hypothesized that there might be differences in reliability and the incidence of side effects. METHODS: In a retrospective quality management analysis of 118 patients (MagStim™ electrode, 57 patients; Xomed™ ETT, 61 patients), we compared laryngeal side effects according to the Chilla score and detection rate of the RLN. RESULTS: Both systems had comparable detection rates of the RLN above 95%. Both electrode systems seemed to have similar reliability. Difficulties to detect the nerve were observed in seven patients (four with MagStim, three with Xomed). In the group with the Xomed™ ETT, significantly less mild laryngeal side effects were observed. CONCLUSION: Both MagStim™ and Xomed™ ETT were reliable in detecting the RLN. The Xomed™ ETT, however, might cause milder laryngeal side effects compared with the MagStim™ electrode.

Electromyographic response persists after peripheral transection: endorsement of current concepts in recurrent laryngeal nerve monitoring in a porcine model.

BACKGROUND: Recurrent laryngeal nerve palsy is a serious complication of endocrine surgery to the neck. Permanent lesions are still occurring in about one in a hundred, despite standardized surgical approach to the nerve and the availability of recurrent laryngeal nerve monitoring. Intraoperative recurrent laryngeal nerve monitoring is based on the visual or acoustic registration of evoked electromyography of the laryngeal muscles. Primarily, it proves conductivity of the stimulated nerve segment towards the muscle, so that stimulation distal of the lesion should show persistent electromyographic response. METHODS: In a porcine model, an iatrogenic nerve lesion of the recurrent laryngeal nerve was set. Subsequently, the proximal and distal dissected nerve portion was stimulated and the evoked electromyographic response of the laryngeal muscles was recorded by needle and laryngeal surface electrodes. RESULTS: As expected, no signal was obtained from the proximal segment. Meanwhile, the distal segment showed unchanged amplitude of the electrophysiological response for the observation period of more than 1 h. CONCLUSION: This result demonstrated a remarkable pitfall for the neuromuscular monitoring at the recurrent laryngeal nerve: In the human surgical setting, this might have resulted in the false assumption of an anatomical intact nerve. The persistence of distal electromyographic conduction strengthens the proposal to stimulate the vagal nerve as the proximal portion of the nerve as a part of a systematic protocol.