Lung separation and the difficult airway

High-flow nasal oxygenation versus face mask oxygenation for preoxygenation in patients undergoing double-lumen endobronchial intubation: protocol of a randomised controlled trial

INTRODUCTION

With the growing emphasis on swift recovery, minimally invasive thoracic surgery has advanced significantly. Video-assisted thoracoscopic surgery (VATS) has seen rapid development, and the double-lumen tube (DLT) remains the most dependable method for tracheal intubation in VATS. However, hypoxaemia during DLT intubation poses a threat to the perioperative safety of thoracic surgery patients. Recently, transnasal high-flow nasal oxygen (HFNO) has shown promise in anaesthesia, particularly in handling short-duration hypoxic airway emergencies. Yet, its application in the perioperative period for patients undergoing pulmonary surgery with compromised cardiopulmonary function lacks evidence, and there are limited reliable clinical data.

METHODS AND ANALYSIS

A prospective, randomised, controlled, single-blind design will be employed in this study. 112 patients aged 18-60 years undergoing elective VATS-assisted pulmonary surgery will be enrolled and randomly divided into two groups: the nasal high-flow oxygen group (H group) and the traditional mask transnasal oxygen group (M group) in a 1:1 ratio. HFNO will be used during DLT intubation for the prevention of asphyxia in group H, while conventional intubation procedures will be followed by group M. Comparison will be made between the two groups in terms of minimum oxygen saturation during intubation, hypoxaemia incidence during intubation, perioperative complications and postoperative hospital days.

ETHICS AND DISSEMINATION

Approval for this study has been granted by the local ethics committee at Shenzhen Second People's Hospital. The trial results will be disseminated through peer-reviewed journals and scientific conferences.

TRIAL REGISTRATION NUMBER

NCT05666908.

Research and development of the sOLVe Tube™ dual lumen endobronchial tube: from concept to construct

Introduction

Dual lumen endobronchial tubes (DLTs) are frequently used for lung isolation and one lung ventilation in thoracic surgery and other specialized clinical scenarios. Modern DLTs are large and rigid, and account for half of all tracheobronchial injuries. Their 70 year old design has numerous flaws which limit their safety and clinical utility. Our research team set out to design a new and improved DLT to mitigate these shortcomings, and then test the proposed device to ensure proper function.

Methods

Using published airway anatomy data and computed tomography imaging from 195 thoracic surgery patients, we designed a new DLT with a single size/configuration that would fit into adult surgery patients. This single "Universal design" was intended to replace both left and right sided 35Fr-41Fr DLTs (8 total products), while remaining small in diameter (35Fr). Other design goals included: 1) making intubation easier and safer, 2) allowing full sized therapeutic bronchoscopes to fit into this tube, 3) making the DLT more resistant to dislodgement. After design process completion the proposed dimensions were tested against 195 patients' left and right mainstem bronchi for radiographic fit. Once production prototypes were manufactured, they were tested in large adult Yorkshire pigs and fresh human cadavers for anatomic fit and performance.

Results

The proposed design passed the radiographic fit test in all 195 patients for both left and right mainstem endobronchial placement. Intubation was successful and deemed atraumatic in all pigs and cadavers, and the device appropriately fit in both the right and left mainstem bronchi. Lung isolation was successfully achieved and the device proved resistant to axial force dislodgement.

Conclusion

We propose a new design for a novel DLT meant to replace 8 currently supplied adult configurations with a single, one size/configuration fits all product that allows for large bore bronchoscopy and resists axial force dislodgement.

Tracheal Bronchus and Successful Right-Sided Isolation With a Bronchial Blocker

The presence of a tracheal bronchus, which is often incidentally discovered, complicates endotracheal intubation and lung isolation during thoracic surgery. Prior reports of successful right-sided lung isolation in the presence of tracheal bronchus required utilization of a double lumen tube. Although right-sided lung isolation was required in our case, due to other patient factors, it was determined that a double lumen tube of a suitable size would be unlikely to be placed safely and successfully. We describe the successful use of a Rüsch EZ-Blocker bronchial blocker in obtaining right-sided isolation in a patient with a difficult airway and tracheal bronchus.

Comparison of silicone double-lumen tube and polyvinyl chloride single-lumen tube in fiberoptic tracheal intubation on a difficult airway model: a randomized controlled non-inferiority trial

The management of patients with history or suspicion of difficult intubation can be challenging, especially in surgical procedures requiring one-lung ventilation. The ease of insertion of silicone double lumen tube (DLT) have previously been shown to be comparable to polyvinyl single lumen tube (SLT) in fiberoptic bronchoscope (FOB) tracheal intubation. Hence, in difficult airway situation, we hypothesized that the performance of insertion of silicone DLT would also be non-inferior to polyvinyl SLT in FOB intubation. We used a neck collar to mimic patients with difficult airway. 80 patients who required one-lung ventilation were enrolled in a prospective, randomized, non-inferiority trial. Patients were randomly allocated to the DLT or SLT groups (SLT with bronchial blocker). Neck collar was supplied to all patients before FOB intubation. The time of insertion for FOB, railroading, tracheal intubation, and total procedure were measured. The difficulty of railroading was evaluated in 4 grades. In the DLT group, the railroading was significantly shorter and easier comparing to the SLT group. The total procedure was also simpler and faster in the DLT group. While simulated difficult airways may not fully replicate actual difficult airways, we suggest that fiberoptic intubation with silicone DLT could be a feasible first-line option for patients with expected difficult airways requiring lung separation, unless the size of the DLT relative to the patient's airway is problematic.Trial registration: NCT03392766.

Effect of Minimum Bronchial Cuff Volume of Left-Sided Double-Lumen Tube for One-Lung Ventilation on the Change in Bronchial Cuff Pressure during Lateral Positioning in Thoracic Surgery: A Prospective Observational Study

The minimum bronchial cuff volume (BCVmin) of a double-lumen tube (DLT) without air leaks during lung isolation may vary among individuals, and lateral positioning could increase the bronchial cuff pressure (BCP). We investigated the effect of initially established BCVmin (BCVi) on the change in BCP by lateral positioning. Seventy patients who underwent elective lung surgery were recruited and divided into two groups according to the BCVi obtained during anesthetic induction in each patient. Outcome analysis was conducted using data from 39 patients with a BCVi greater than 0 (BCVi > 0 group) and 27 with a BCVi of 0 (BCVi = 0 group). The primary outcome was a change in the value measured in the supine and lateral positions of the initially established BCP (BCPi; BCP at the time of BCVi injection), which was significantly larger in the BCVi > 0 group than in the BCVi = 0 group (1.5 (0.5-6.0) cmH₂O vs. 0.0 (0.0-1.0) cmH₂O; p < 0.001). BCVi was related to the left main bronchus (LMB) diameter (Spearman's rho = 0.676, p < 0.001) and the gap between the LMB diameter and the outer diameter of the bronchial cuff (Spearman's rho = 0.553, p < 0.001). Therefore, selecting a DLT size with a bronchial cuff that fits each patient's LMB may be useful in minimizing the change in BCP when performing lateral positioning during thoracic surgery. If the bronchial cuff requires unavoidable initial inflation, it is necessary to be aware that BCP may increase during lateral positioning and to monitor the BCP regularly if possible.

A Randomized Study of Rigid Video Stylet versus Macintosh Laryngoscope for Double-Lumen Endobronchial Tube Intubation Assistance in Thoracoscopic Pulmonary Surgery

Double-lumen endobronchial tube (DLT) intubation is more challenging than single-lumen tube intubation is, and the rigid video stylet (RVS) is one of the tools that has emerged to deal with this demanding intubation procedure. We evaluated whether the UE® RVS can shorten the DLT intubation time and improve the first-attempt intubation success rate compared with that of Macintosh laryngoscope (ML). A total of 130 participants scheduled to undergo thoracoscopic pulmonary surgeries were enrolled. They were randomized to receive either ML- or RVS-assisted DLT intubation. The primary outcomes were the intubation time and first-attempt intubation success rate. The secondary outcomes were the overall intubation success rate, mean arterial pressure, postoperative sore throat (POST), and postoperative hoarseness at 1 h and 24 h. Compared with the ML group, the intubation time was significantly shorter in the RVS group (p < 0.001; 30.82 ± 10.61 vs. 39.62 ± 6.54 s), however, the first-attempt success rate was significantly lower (p = 0.048; 83.08% vs. 95.16%). The POST at 1 h was less severe in the RVS group (p = 0.021). No significant differences were found for the other indicators. Among the patients with normal airways, the UE® RVS can achieve faster DLT intubation and decrease the severity of a POST at 1 h, although it was associated with a lower first-attempt intubation success rate.

Recent Advances in Videolaryngoscopy for One-Lung Ventilation in Thoracic Anesthesia: A Narrative Review

Since their advent, videolaryngoscopes have played an important role in various types of airway management. Lung isolation techniques are often required for thoracic surgery to achieve one-lung ventilation with a double-lumen tube (DLT) or bronchial blocker (BB). In the case of difficult airways, one-lung ventilation is extremely challenging. The purpose of this review is to identify the roles of videolaryngoscopes in thoracic airway management, including normal and difficult airways. Extensive literature related to videolaryngoscopy and one-lung ventilation was analyzed. We summarized videolaryngoscope-guided DLT intubation techniques and discussed the roles of videolaryngoscopy in DLT intubation in normal airways by comparison with direct laryngoscopy. The different types of videolaryngoscopes for DLT intubation are also compared. In addition, we highlighted several strategies to achieve one-lung ventilation in difficult airways using videolaryngoscopes. A non-channeled or channeled videolaryngoscope is suitable for DLT intubation. It can improve glottis exposure and increase the success rate at the first attempt, but it has no advantage in saving intubation time and increases the incidence of DLT mispositioning. Thus, it is not considered as the first choice for patients with anticipated normal airways. Current evidence did not indicate the superiority of any videolaryngoscope to another for DLT intubation. The choice of videolaryngoscope is based on individual experience, preference, and availability. For patients with difficult airways, videolaryngoscope-guided DLT intubation is a primary and effective method. In case of failure, videolaryngoscope-guided single-lumen tube (SLT) intubation can often be achieved or combined with the aid of fibreoptic bronchoscopy. Placement of a DLT over an airway exchange catheter, inserting a BB via an SLT, or capnothorax can be selected for lung isolation.

Lung ultrasound is non-inferior to bronchoscopy for confirmation of double-lumen endotracheal tube positioning: a randomized controlled noninferiority study

BACKGROUND

Appropriate placement of left-sided double-lumen endotracheal tubes (LDLTs) is paramount for optimal visualization of the operative field during thoracic surgeries that require single lung ventilation. Appropriate placement of LDLTs is therefore confirmed with fiberoptic bronchoscopy (FOB) rather than clinical assessment alone. Recent studies have demonstrated lung ultrasound (US) is superior to clinical assessment alone for confirming placement of LDLT, but no large trials have compared US to the gold standard of FOB. This noninferiority trial was devised to compare lung US with FOB for LDLT positioning and achievement of lung collapse for operative exposure.

METHODS

This randomized, controlled, double-blind, noninferiority trial was conducted at the Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand from October 2017 to July 2019. The study enrolled 200 ASA classification 1-3 patients that were scheduled for elective thoracic surgery requiring placement of LDLT. Study patients were randomized into either the FOB group or the lung US group after initial blind placement of LDLT. Five patients were excluded due to protocol deviation. In the FOB group (n = 98), fiberoptic bronchoscopy was used to confirm lung collapse due to proper positioning of the LDLT, and to adjust the tube if necessary. In the US group (n = 97), lung ultrasonography of four pre-specified zones (upper and lower posterior and mid-axillary) was used to assess lung collapse and guide adjustment of the tube if necessary. The primary outcome was presence of adequate lung collapse as determined by visual grading by the attending surgeon on scale from 1 to 4. Secondary outcomes included the time needed to adjust and confirm lung collapse, the time from finishing LDLT positioning to the grading of lung collapse, and intraoperative parameters such has hypotension or hypertension, hypoxia, and hypercarbia. The patient, attending anesthesiologist, and attending thoracic surgeon were all blinded to the intervention arm.

RESULTS

The primary outcome of lung collapse by visual grading was similar between the intervention and the control groups, with 89 patients (91.8%) in the US group compared to 83 patients (84.1%) in the FOB group (p = 0.18) experiencing adequate collapse. This met criteria for noninferiority per protocol analysis. The median time needed to confirm and adjust LDLT position in the US group was 3 min (IQR 2-5), which was significantly shorter than the median time needed to perform the task in the FOB group (6 min, IQR 4-10) (p = 0.002).

CONCLUSIONS

In selected patients undergoing thoracic surgery requiring LDLT, lung ultrasonography was noninferior to fiberoptic bronchoscopy in achieving adequate lung collapse and reaches the desired outcome in less time.

TRIAL REGISTRATION

This study was registered at clinicaltrials.gov, NCT03314519 , Principal investigator: Kasana Raksamani, Date of registration: 19/10/2017.

Double-lumen tube versus bronchial blocker in lymphadenectomy along the left recurrent laryngeal nerve for esophageal cancer: a propensity-matched analysis

BACKGROUND

Lymph node (LN) dissection along left recurrent laryngeal nerve (RLN) is challenging in esophagectomy for esophageal cancer, and double-lumen endotracheal tube (DLT) impedes the exposure of this area. The aim of this study was to determine whether bronchial blockers (BB) could be a better choice for this procedure.

METHODS

The clinical characteristics of patients who received McKeown esophagectomy with radical lymph node dissection in Wuhan Tongji Hospital between August 2017 and July 2019 were retrospectively analyzed. The 1:1 propensity score match analysis was performed to compare the short-term effectiveness, the numbers of lymph nodes dissected, and the patterns of recurrence and survival between the two groups.

RESULTS

A total of 294 patients (192 and 102 in the DLT and BB group, respectively) were enrolled in the study. After matching, 204 patients (102 pairs) who underwent one-lung ventilation with DLT or BB displayed no significant variance in baseline characteristics. The BB group had higher number of LNs resected along left RLN (1.8 ± 2.3 vs. 2.5 ± 2.5, P = 0.001). For patients with metastatic left RLN LN, the BB group had longer medium survival time (15 vs. 32 months, P = 0.045), and tended to have longer medium recurrence-free survival time (6 vs. 15 months, P = 0.079), and lower rate of upper mediastinal and cervical LN recurrence (30.00% vs. 66.67%, P = 0.198). The postoperative complications were similar in both groups.

CONCLUSIONS

Compared with DLT, using BB in esophagectomy may allow more radical lymphadenectomy along left RLN.

Difficult lung separation. An insight into the challenges faced during COVID-19 pandemic

Difficult lung isolation or separation in patients undergoing thoracic surgery using one-lung ventilation might be attributed to upper airway difficulty or abnormal anatomy of the lower airway. Additionally, adequate deflation of the surgical lung can impair surgical exposure. The coronavirus disease 2019 (COVID-19) has a harmful consequence for both patients and anesthesiologists. Management of patients with difficult lung isolation can be challenging during the COVID-19 pandemic. Careful planning and preparation, preoperative routine testing, protective personal equipment, standard safety measures, proper preoxygenation, and individualize the patients care are required for successful lung separation. A systematic approach for management of difficult lung separation is centered around securing the airway and providing adequate ventilation using either a blocker or double-lumen tube. Several measures are described to expedite lung collapse.

Use of a modified tracheal tube in a child with traumatic bronchial rupture: A case report and review of literature

BACKGROUND

Trauma is one of the leading causes of death in the pediatric population. Bronchial rupture is rare, but there are potentially severe complications. Establishing and maintaining a patent airway is the key issue in patients with bronchial rupture. Here we describe an innovative method for maintaining a patent airway.

CASE SUMMARY

A 3-year-old boy fell from the seventh floor. Oxygenation worsened rapidly with pulse oxygen saturation decreasing below 60%, as his heart rate dropped. Persistent pneumothorax was observed with insertion of the chest tube. Fiberoptic bronchoscopy was performed, which confirmed the diagnosis of bronchial rupture. A modified tracheal tube was inserted under the guidance of a fiberoptic bronchoscope. Pulse oxygen saturation improved from 60% to 90%. Twelve days after admission, right upper lobectomy was performed using bronchial stump suture by video-assisted thoracic surgery without complications. A follow-up chest radiograph showed good recovery. The child was discharged from hospital three months after admission.

CONCLUSION

A modified tracheal tube could be selected to ensure a patent airway and adequate ventilation in patients with bronchial rupture.

A Tale of 2 Tubes for Emergency Management of Airway Obstruction From an Anterior Mediastinal Mass: A Case Report

Anterior mediastinal masses are challenging. As induction of general anesthesia may result in complete airway obstruction or hemodynamic collapse, maintaining spontaneous ventilation and advancing the endotracheal tube (ETT) distal to the mass are recommended. We discuss the emergency management of an anterior mediastinal mass-induced near-complete airway obstruction at the carina. Despite maintaining spontaneous ventilation, airway obstruction persisted following placement of the ETT proximal to the obstruction. After advancing the ETT into the right mainstem bronchus distal to the mass, hypoxemia persisted, prompting placement of a second ETT into the left mainstem bronchus to overcome the obstruction and provide adequate oxygenation.

Changes in the Bronchial Cuff Pressure of Left-Sided Double-Lumen Endotracheal Tube by Lateral Positioning: A Prospective Observational Study

Proper bronchial cuff pressure (BCP) is important when using a double-lumen endotracheal tube (DLT), especially in thoracic surgery. As positional change during endotracheal tube placement could alter cuff pressure, we aim to evaluate the change in BCP of DLT from the supine to the lateral decubitus position during thoracic surgery. A total of 69 patients aged 18–70 years who underwent elective lung surgery were recruited. BCP was measured at a series of time points in the supine and lateral decubitus positions after confirming the DLT placement. The primary outcome was change in the initial established BCP (BCPi), which is the maximum pressure at which the BCP did not exceed 40 cmH₂O without air leak in the supine position, after lateral decubitus positioning. As the primary outcome, the BCPi increased from 25.4 ± 9.0 cmH₂O in the supine position to 29.1 ± 12.2 cmH₂O in the lateral decubitus position (p < 0.001). Out of the 69 participants, 43 and 26 patients underwent surgery in the left-lateral decubitus position (LLD group) and the right-lateral decubitus position (RLD group) respectively. In the LLD group, the BCPi increased significantly (p < 0.001) after lateral positioning and the beginning of surgery and the difference value, ∆BCPi, from supine to lateral position was significantly higher in the LLD group than in the RLD group (p = 0.034). Positional change from supine to lateral decubitus could increase the BCPi of DLT and the increase was significantly greater in LLD that in RLD.

Comparison of different size left-sided double-lumen tubes for thoracic surgery

Study Objective

The aim of this study is to see if there are any clinical differences between using 35 F DLT for all patients versus using patient height regardless of gender to estimate appropriate DLT size.

Design

Prospective randomized study.

Setting

University Hospital.

Patients

50 patients age ≤18 years, undergoing lung or esophageal surgery requiring OLV.

Interventions

Patients randomized to two groups (group-35F, group -DLT based on height).

Measurements and Main Results

Data collected include demographics, ASA status, airway assessment, number of intubation attempts, Cormack-Lehane grade, number of times DLT repositioned, incidence of sore throat, oxygen saturation at induction and oxygen saturation at 5 minutes and 10 minutes after OLV. There was no statistically significant difference in demographics, ASA classification, Mallampati score, number of intubation attempts, Cormack-Lehane grade, number of times DLT was repositioned, and incidence of sore throat. In height based DLT group the odds were higher for the incidence of sore throat in 37-41 F group. Oxygen saturation at induction, 5 minutes and 10 minutes after OLV are not statistically significant between the two groups. Conclusion: Our findings suggest that the majority of patients receive unnecessarily large DLTs for thoracic surgery, which not only makes intubation inherently more difficult but also increases their risk of postoperative sore throat.

A rare anaesthetic challenge in a one-lung ventilated paediatric patient with right upper lobe tracheal bronchus

A tracheal bronchus is a rare congenital anomaly, suggesting abnormal bronchial development. The prevalence of tracheal bronchus in children who undergo bronchoscopy is estimated to be between 0.2% and 3%. When associated with recurrent infection, lobes of the lung must be removed to avoid further lung injury. In such cases, perioperative one-lung ventilation and airway management remain a huge challenge for anaesthesiologists. The case of this rare airway anatomic abnormality in a paediatric patient with two bronchial openings into the right upper lobe, and with a history of recurrent pneumonia, is reported. In addition to a normal opening, a distinct opening in the upper lobe of the right lung was observed, that originated directly from the trachea, superior to the carina. The entire right lung was deflated by left-lung ventilation using a single lumen tracheal tube, and the patient underwent right upper lobe resection. No anaesthesia complications were observed during recovery. In this case, timely identification of the tracheal bronchus and successful collapse of the right lung were key points in the anaesthesia management of this patient.

Extraluminal bronchial blocker placement using both nostrils for lung isolation in a patient with limited mouth opening: A CARE-compliant case report

RATIONALE

The establishment of lung isolation is often particularly challenging for the anesthesiologist in patients with difficult airway. Usually, orotracheal intubation with double lumen tube is the commonly used technique for achieving 1 lung anesthesia. Whereas, in patients with limited mouth opening and restricted cervical mobility, this technique becomes extremely difficult and hazardous. We report a case in which bronchial blocker placement was succeeded via both nostrils in a difficult airway due to restricted mouth opening.

PATIENT CONCERNS

A 50-year-old, non-smoking female with a painless mass in the left upper lobe. She had a 10-year history of ankylosing spondylitis and squamous cell carcinoma of the floor of the mouth after 5 operations 4 years previously.

DIAGNOSES

Left upper lobe adenocarcinoma, ankylosing spondylitis and oral squamous cell carcinoma.

INTERVENTIONS

To achieve 1 lung anesthesia, both nostrils were used for extraluminal bronchial blocker placement.

OUTCOMES

Initially, oral intubation was selected for establishing a patent airway but failed. Then switched to nasal canal for insertion, after several attempts, a conventional nasal intubation tube (internal diameter 6.0 mm) was placed via 1 nostril under topical anesthesia, with the aid of a flexible fiberoptic bronchoscope, and a bronchial blocker was advanced to the desired position via the other nostril.

LESSONS

In difficult airway with limited mouth opening and restricted cervical mobility, multidisciplinary experts participated discussion is a prerequisite for contemplating a scientific plan. Preoperative computed tomography scan and 3-dimensional computed tomography reconstruction would be helpful in detecting the narrowest part of airway conduit and determining a safe, reliable, and feasible airway program.

Technical Issues and Patient Safety in Nonintubated Thoracic Anesthesia

Nonintubated thoracic surgery (NITS) has a good safety record in experienced hands, but has pitfalls for beginners. The main aim of NITS is to keep the patient under spontaneous respiration, avoiding adverse effects, such as hypoxemia, hypercapnia, panic attacks, and finally conversion to general anesthesia. In this paper, the safety aspects of anesthesia for NITS is discussed based on data from the literature and personnel clinical experiences.

Successful blind lung isolation with the use of a novel double-lumen endobronchial tube in a patient undergoing lung transplantation with massive pulmonary secretion: A case report

RATIONALE

Precise lung isolation technique with visual confirmation is essential for thoracic surgeries to create a safe and clear surgical field. However, in certain situations, such as when patients have massive pulmonary secretion or when the fiberoptic bronchoscopy (FOB) is not applicable, lung isolation has been performed blindly.

PATIENT CONCERN

A 52-year-old woman, whose airway was unable to visualize with FOB due to massive pulmonary secretion, was presented for bilateral sequential lung transplantation. Extracorporeal membranous oxygenation, tracheostomy, and mechanical ventilation were applied to the patient for 39 days preoperatively as a bridge for lung transplantation.

DIAGNOSIS

Patient was diagnosed with an idiopathic pulmonary fibrosis and obesity.

INTERVENTION

Initially, height-based blind positioning with a conventional double-lumen endobronchial tube (DLT) failed to ventilate the patient properly, and the confirmation of DLT positioning with FOB was impossible due to massive pulmonary secretion. Therefore, a novel DLT (ANKOR DLT) that has one more cuff, located at a point between the distal opening of the tracheal lumen and the starting point of bronchial cuff, than conventional DLT was used for the lung isolation in the patient.

OUTCOMES

After the completion of lung graft, FOB finding showed that the ANKOR DLT was optimally positioned at the tracheobronchial tree of the patient, and its depth was 2.5 cm shallower than that of the conventional tube.

LESSONS

ANKOR DLT would be a feasible choice to achieve successful blind lung isolation when the use of FOB is impossible to achieve the optimal lung isolation.

Lung Isolation in the Patient With a Difficult Airway

One-lung ventilation is routinely used to facilitate exposure for thoracic surgical procedures and can be achieved via several lung isolation techniques. The optimal method for lung isolation depends on a number of factors that include (1) the indication for lung isolation, (2) anatomic features of the upper and lower airway, (3) availability of equipment and devices, and (4) the anesthesiologist's proficiency and preferences. Though double-lumen endobronchial tubes (DLTs) are most commonly utilized to achieve lung isolation, the use of endobronchial blockers offer advantages in patients with challenging airway anatomy. Anesthesiologists should be familiar with existing alternatives to the DLT for lung isolation and alternative techniques for DLT placement in the patient with a difficult airway. Newer technologies such as videolaryngoscopy with or without adjunctive fiberoptic bronchoscopy may facilitate intubation and lung isolation in difficult airway management.

Effect of lateral positioning on the bronchial cuff pressure of a left-sided double-lumen endotracheal tube during thoracic surgery: study protocol for a prospective observational study

INTRODUCTION

Correct pressure is important when using a double-lumen endotracheal tube (DLT), especially in thoracic surgery. An inadequate bronchial cuff pressure (BCP) can cause air leak and interfere with visualisation of the surgical field, whereas an excessive pressure BCP can lead to cuff-related complications. Based on several reports that cuff pressure could alter after a positional change when using an endotracheal tube, we hypothesise that a change from the supine position to the lateral decubitus position, which is essential for thoracic surgery, would affect the BCP of the DLT.

METHODS AND ANALYSIS

This prospective, single-centre, observational study will enrol 74 patients aged 18-70 years undergoing elective lung surgery from September 2018 to April 2019. The primary outcome will be the change in the 'initially established BCP' (maximum BCP not exceeding 40 cm H₂O with no air leak in the supine position) after lateral decubitus positioning. BCP and air leak will be assessed in each patient position during inflation of the cuff with air in 0.5 mL increments from 0 to 3 mL. Secondary outcomes will include the incidence of BCP exceeding 40 cm H₂O after the initial established value and that of a change in the smallest bronchial cuff volume without air leak after a change to the lateral position. The relationship between the change in BCP and airway pressure, compliance and body mass index after lateral positioning will be investigated.

ETHICS AND DISSEMINATION

The study will be conducted in accordance with the Declaration of Helsinki and supervised by the Daegu Catholic University Medical Center institutional review board (study approval number CR-18-111). All patients will receive information about the study and will need to provide written informed consent before enrolment. The results will be presented at an international meeting and published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT03656406; Pre-results.

Time to tracheal intubation over a fibreoptic bronchoscope using a silicone left double-lumen endobronchial tube versus polyvinyl chloride single-lumen tube with bronchial blocker: a randomized controlled non-inferiority trial

Background

Direct insertion of a double-lumen endobronchial tube (DLT) over a fibreoptic bronchoscope (FOB) is considered more difficult and traumatic than that of a single-lumen tube (SLT). We hypothesized that time to intubation over an FOB using a silicone left DLT would be non-inferior to that using a polyvinyl chloride (PVC) SLT.

Methods

Eighty patients were enrolled in this open-label, randomized controlled, non-inferiority trial. Patients were randomly allocated to fibreoptic tracheal intubation with either a silicone DLT or PVC SLT (DLT and SLT groups, respectively). Time to tracheal intubation [time to insertion of FOB plus railroading (advancement over the FOB) time]; total time for correct tube and bronchial blocker positioning; difficulty of railroading; and the incidence of sore throat, swallowing difficulty, and hoarseness were compared between groups.

Results

The median time to intubation over the FOB was 20 s in the DLT group and 23 s in the SLT group. The upper limit of the confidence interval of this difference was below the non-inferiority margin of 10 s (median difference: -2 s; 95% confidence interval: -4 to 0 s). Railroading time was significantly shorter in the DLT group than in the SLT group (median time: 10 vs. 11 s; median difference: -1 s; 95% confidence interval: -3 to 0 s; P=0.03). Railroading over the FOB (rated on a four-point scale) was less difficult in the DLT group than in the SLT group (P<0.01).

Conclusions

Tracheal intubation using an FOB can be achieved at least as fast using the silicone DLT as using the PVC SLT. The silicone DLT exhibited superior railroading performance to the PVC SLT.

A randomised trial comparing real-time double-lumen endobronchial tube placement with the Disposcope® with conventional blind placement

Double-lumen endobronchial tube placement is challenging. This study compared double-lumen tube placement with the Disposcope^® , a wireless videostylet allowing real-time visualisation, with conventional blind placement. Patients undergoing elective thoracic surgery with normal airways requiring one-lung ventilation were randomly allocated into two groups (27 patients in each group). The Disposcope was used to assist left-sided double-lumen tube placement in one group, and conventional blind placement was performed in the control group. Placement in both groups was checked with fibreoptic bronchoscopy. The Disposcope-assisted group had a shorter total mean (SD) placement time (18.6 (2.5) s vs. 21.4 (2.9) s, p < 0.001), laryngoscopy to end of auscultation time (83.4 (3.0) s vs. 93.9 (5.7) s, p < 0.001) and total operation time (130.7 (6.1) s vs. 154.5 (6.3) s, p < 0.001). In the Disposcope-assisted group, the double-lumen tube was inserted in the correct side in all patients (100.0%), whereas in the conventional group, the double-lumen tube was placed in the correct side in 25 (92.6%) patients and in the wrong side in 2 (7.4%) patients; the difference was not significant (p = 0.150). In the Disposcope-assisted group, the double-lumen tube was inserted to the optimal depth in 24 (88.9%) patients, whereas in the conventional group it was inserted to the optimal depth in one (4.0%) patient. The Disposcope increased the success rate of double-lumen tube placement, and shortened the total operation time when compared with standard placement with confirmation using fibreoptic bronchoscopy, and may replace the conventional method.

Thyromental height test as a new method for prediction of difficult intubation with double lumen tube

Background

Predicting difficult intubation is of high clinical interest.

Methods

237 patients aged ≥18 years were included in the study. Preoperative airway evaluation included: Mallampati test, thyromental distance, sternomental distance and thyromental height test. During direct laryngoscopy Cormack & Lehane classification was graded. We calculated the ROC AUC, sensitivity and specificity for thyromental height test as a primary end point of our study.

Results

Only thyromental height test and Cormack-Lehane scale proved significant on occurrence of difficult intubation. The optimal sensitivity and specificity values of thyromental height test were met with a cut off value of 50 mm. With 1 mm increase in thyromental height test, risk of difficult intubation decreased by 7%.

Conclusion

Thyromental height test is a simple, easy to perform and non-invasive test to predict difficult intubation in patients scheduled for elective double lumen tube intubation during thoracic surgical procedures. With 1 mm above 50 mm increase in thyromental height test the risk of difficult intubation decreased by 7%.

Trial registration

Clinicaltrials.gov Identifier: NCT02988336.

One-lung ventilation in a patient with a large mass on the glottis: A case report

RATIONALE

One-lung ventilation (OLV) is required during most thoracic surgeries to facilitate surgical visualization by collapsing the lung. Double-lumen tubes and bronchial blockers are two commonly used devices for OLV; however, it may be difficult to place two devices in patients with narrow inlets, such as those that have tumor-induced airway stenosis.

PATIENT CONCERNS

We report the case of an adult patient with a lung tumor that was growing rapidly and hemorrhaging; thus, a thoracotomy for lung resection should have been performed as early as possible. However, a large mass on the glottis obstructed the entry of the double-lumen tube or bronchial blocker. Therefore, the operation could not be performed because of the inability to provide one-lung ventilation via the conventional intubation method.

DIAGNOSES

Computed tomography (CT) revealed a lung tumor that was growing rapidly and preoperative bronchoscopy showed a large mass on the vocal cords.

INTERVENTIONS

After anesthesia induction, a Uniblocker and a small single lumen tube were intubated and the Uniblocker was inserted extraluminally of the single lumen tube. One-lung ventilation was achieved successfully in this patient.

OUTCOMES

The surgery proceeded uneventfully for 4 hours without any complications.

LESSONS

Extraluminal use of the Uniblocker and a small single lumen tube may be recommended for patients receiving OLV and who have narrow inlets, especially under emergency situations.

Use of bronchial blocker in emergent thoracotomy in presence of upper airway hemorrhage, and cervical spine fracture: a difficult decision

Female, 85 y.o., weighting 60 kg, multiple trauma patient. After an initial laparotomy, an emergent thoracotomy was performed using a bronchial blocker for lung isolation (initial active suction was applied). During surgery, bronchial cuff was deflated, causing a self-limited tracheal blood flooding. A second lung isolation was attempted but it was not as effective as initially. Probably, a lung collapse with the same bronchial blocker was impaired in the second attempt because of the obstruction of bronchial blocker lumen by intraoperative endobronchial hemorrhage. Bronchial blocker active suction may contribute to obtain or accelerate lung collapse, particularly in patients that do not tolerate ventilator disconnection technique or lung surgical compression. The use of bronchial blockers technology was a valuable alternative to double lumen tubes in this case of emergent thoracotomy in the context of a patient having thoracic, abdominal trauma, severe laceration of tongue and apophysis odontoid fracture associated to massive hemorrhage, despite several pitfalls that could compromise its use. The authors intend to discuss the advantages and disadvantages of bronchial blockers comparing to double-lumen tubes for lung isolation, and the risks of our approach, in this complex multitrauma case.

Lung Isolation Techniques in Patients With Early-Stage or Long-Term Tracheostomy: A Case Series Report of 70 Cases and Recommendations

OBJECTIVES

Lung isolation techniques are designed to facilitate surgical exposure in thoracic surgical patients and provide one-lung ventilation (OLV). Some patients have a tracheostomy in situ, which makes the management of the airway and OLV difficult. The objective of this retrospective study was to review cases that had a tracheostomy prior to thoracic surgery and evaluate the clinical use and efficiency with the airway management and lung isolation devices.

DESIGN

This was a retrospective data analysis.

SETTING

Tertiary care university hospital.

INTERVENTIONS

After institutional review board approval, the authors reviewed 3,225 charts of patients who had thoracic surgery involving OLV. Seventy patients were identified who had tracheostomy in situ. Each case was reviewed regarding airway management and lung isolation technique.

MEASUREMENTS AND MAIN RESULTS

The authors identified 70 patients who had a tracheostomy in situ. The cases were divided into 2 groups: a fresh tracheostomy stoma <7 days (n = 6) or long-term stoma >7 days (n = 64). The authors collected information regarding the devices used to manage the airway and lung isolation techniques. The devices used to manage the airway include the Shiley cuffed low pressure tracheostomy tube, single-lumen endotracheal tube (SLT), or double-lumen endotracheal tube (DLT). Devices used to manage OLV included SLTs, with or without bronchial blockers, or DLTs. Flexible fiberoptic bronchoscopy was used to assess the airway and confirm the position of the lung isolation device. Six cases had an early-stage fresh tracheostomy stoma where the Shiley tracheostomy tube was used for ventilation followed by the use of a bronchial blocker. In contrast, for the patients who had a long-term stoma, the following devices were used: (1) a SLT plus a bronchial blocker in 38 cases, a Shiley tracheostomy tube plus bronchial blocker in 15 cases, use of a SLT guided into a selective bronchus in 7 cases, and use of a DLT in 4 cases. In all cases, flexible fiberoptic bronchoscopy was used and no complications occurred secondary to airway management or OLV.

CONCLUSION

In patients undergoing thoracic surgery and OLV, and with a fresh tracheostomy stoma in situ, the authors recommend the use of the Shiley tracheostomy tube plus a bronchial blocker. In patients with a long-term tracheostomy stoma, a SLT can be used selectively to intubate 1 bronchus. In addition, an SLT or a Shiley tube can be used in conjunction with an independent bronchial blocker, such as the Arndt wire-guided bronchial blocker, Cohen tip-deflecting blocker, Fuji Uniblocker, or EZ-Blocker. DLTs are the least frequently used device for OLV in tracheostomized patients.

Videolaryngoscopy vs. Macintosh laryngoscopy for double-lumen tube intubation in thoracic surgery: a systematic review and meta-analysis

Double-lumen intubation is more difficult than single-lumen tracheal intubation. Videolaryngoscopes have many advantages in airway management. However, the advantages of videolaryngoscopy for intubation with a double-lumen tube remain controversial compared with traditional Macintosh laryngoscopy. In this study, we searched MEDLINE, Embase, Cochrane Library and the Web of Science for randomised controlled trials comparing videolaryngoscopy with Macintosh laryngoscopy for double-lumen tube intubation. We found that videolaryngoscopy provided a higher success rate at first attempt for double-lumen tube intubation, with an odds ratio (95%CI) of 2.77 (1.92-4.00) (12 studies, 1215 patients, moderate-quality evidence, p < 0.00001), as well as a lower incidence of oral, mucosal or dental injuries during double-lumen tube intubation, odds ratio (95%CI) 0.36 (0.15-0.85) (11 studies, 1145 patients, low-quality evidence, p = 0.02), and for postoperative sore throat, odds ratio (95%CI) 0.54 (0.36-0.81) (7 studies, 561 patients, moderate-quality evidence, p = 0.003), compared with Macintosh laryngoscopy. There were no significant differences in intubation time, with a standardised mean difference (95%CI) of -0.10 (-0.62 to 0.42) (14 studies, 1310 patients, very low-quality evidence, p = 0.71); and the incidence of postoperative voice change, odds ratio (95%CI) 0.53 (0.21-1.31) (7 studies, 535 patients, low-quality evidence, p = 0.17). Videolaryngoscopy led to a higher incidence of malpositioned double-lumen tube, with an odds ratio (95%CI) of 2.23 (1.10-4.52) (six studies, 487 patients, moderate-quality evidence, p = 0.03).

[Use of bronchial blocker in emergent thoracotomy in presence of upper airway hemorrhage, and cervical spine fracture: a difficult decision]

Female, 85 y.o., weighting 60kg, multiple trauma patient. After an initial laparotomy, an emergent thoracotomy was performed using a bronchial blocker for lung isolation (initial active suction was applied). During surgery, bronchial cuff was deflated, causing a self-limited tracheal blood flooding. A second lung isolation was attempted but it was not as effective as initially. Probably, a lung collapse with the same bronchial blocker was impaired in the second attempt because of the obstruction of bronchial blocker lumen by intraoperative endobronchial hemorrhage. Bronchial blocker active suction may contribute to obtain or accelerate lung collapse, particularly in patients that do not tolerate ventilator disconnection technique or lung surgical compression. The use of bronchial blockers technology was a valuable alternative to double lumen tubes in this case of emergent thoracotomy in the context of a patient having thoracic, abdominal trauma, severe laceration of tongue and apophysis odontoid fracture associated to massive hemorrhage, despite several pitfalls that could compromise its use. The authors intend to discuss the advantages and disadvantages of bronchial blockers comparing to double-lumen tubes for lung isolation, and the risks of our approach, in this complex multitrauma case.

Bronchial blocker positioning: learning curve and confidence in its use

BACKGROUND

Despite being simple and safe to use and cheap, EZ blocker (EZB) remains underused probably because it requires particular skills in recognizing airway and in using fiber-bronchoscopy to check the exact position of their cuffs. Thus, we planned an education training program on the use of EZB for novices in anesthesia and evaluated the number of procedures required for the acquisition of the skills of this technique.

METHODS

The educational training program included three different phases as follows. The first phase included a lecture on the utility of one-lung ventilation in thoracic surgery, on the use of the fiber- bronchoscopy and on the characteristics of EZB. The second phase consisted in a practical teaching course performed on a manikin model to acquire the skills in EZB. The third phase was a clinical training where each participant performed a defined number in patients scheduled for thoracic surgery procedures. The acquisition of dexterity and satisfaction were then statistically valuated.

RESULTS

The dexterity in placing EZB significantly increased after six attempts (P<0.1). Participants acquired skills in correcting position EZB after 15 attempts. Participants increased their level of confidence with EZB (score 5.7±1.3) and were highly satisfied with the training received (score 5.8±1.6).

CONCLUSIONS

EZB is a valid strategy for obtaining one lung ventilation. Thus, it should be included in the armamentarium of all anesthetists interested in the field of thoracic surgery. Our teaching course seems to be a valuable method to instill easily and speedily in training novices in anesthesia the skills in placing EZB.

Comparison of Arndt-endobronchial blocker plus laryngeal mask airway with left-sided double-lumen endobronchial tube in one-lung ventilation in thoracic surgery in the morbidly obese

This study aimed to evaluate the feasibility and performance of Arndt-endobronchial blocker (Arndt) combined with laryngeal mask airway (LMA) compared with left-sided double-lumen endobronchial tube (L-DLT) in morbidly obese patients in one-lung ventilation (OLV). In a prospective, randomized double-blind controlled clinical trial, 80 morbidly obese patients (ASA I-III, aged 20-70) undergoing general anesthesia for elective thoracic surgeries were randomly allocated into groups Arndt (n=40) and L-DLT (n=40). In group Arndt, a LMA™ Proseal was placed followed by an Arndt-endobronchial blocker. In group L-DLT, patients were intubated with a left-sided double-lumen endotracheal tube. Primary endpoints were the airway establishment, ease of insertion, oxygenation, lung collapse and surgical field exposure. Results showed similar ease of airway establishment and tube/device insertion between the two groups. Oxygen arterial pressure (PaO2) of patients in the Arndt group was significantly higher than L-DLT (154±46 vs 105±52 mmHg; P<0.05). Quality of lung collapse and surgical field exposure in the Arndt group was significantly better than L-DLT (effective rate 100 vs 90%; P<0.05). Duration of surgery and anesthesia were significantly shorter in the Arndt group (2.4±1.7 vs 3.1±1.8 and 2.8±1.9 vs 3.8±1.8 h, respectively; P<0.05). Incidence of hoarseness of voice and incidence and severity of throat pain at the post-anesthesia care unit and 12, 24, 48, and 72 h after surgery were significantly lower in the Arndt group (P<0.05). Findings suggested that Arndt-endobronchial blocker combined with LMA can serve as a promising alternative for morbidly obese patients in OLV in thoracic surgery.

Review of difficult airway management in thoracic surgery

The management of difficult airway (DA) in thoracic surgery is more difficult due to the need for lung separation or isolation and frequent presence of associated upper and lower airway problems. We performed an article review analysing 818 papers published with clinical evidence indexed in Pubmed that allowed us to develop an algorithm. The best airway management in predicted DA is tracheal intubation and independent bronchial blockers guided by fibroscopy maintaining spontaneous ventilation. For unpredicted DA, the use of videolaryngoscopes is recommended initially, and adequate neuromuscular relaxation (rocuronium/sugammadex), among other maneuvers. In both cases, double lumen tubes should be reserved for when lung separation is absolutely indicated. Finally, extubation should be a time of maximum care and be performed according to the safety measures of the Difficult Arway Society.

Anaesthesiology for uniportal VATS: double lumen, single lumen and tubeless

The advent of one-lung ventilation (OLV) technique provides immobilized surgical field which is fundamental in minimally invasive thoracic surgery. Mainstem methods of achieving lung separation are either via a double-lumen endotracheal tube or placing a bronchial blocker (BB) through a single-lumen endotracheal tube. More recently, the use of non-intubated thoracic surgery (NITS) has been investigated intensively, attempting to minimise the complications that follow general anaesthesia. The aim of this review is to describe the mechanism of these techniques briefly and outlines the advantages and drawbacks of them with the comparison.

Incidental left main bronchus obstruction during left-sided double-lumen tube intubation of a patient with an unrecognized tracheal bronchus: A case report

INTRODUCTION

Tracheal bronchus is a right-sided anomalous bronchus arising from the trachea above the main carina and occurs in 0.1% to 2% of the general population.

CASE PRESENTATION

We present a case of left main bronchus obstruction during a left-sided double-lumen tube intubation in a patient with an unrecognized tracheal bronchus. After the intubation, to confirm the position of the tube, we observed what we believed was the carina with a fiberoptic bronchoscope, but it was a site between the tracheal bronchus and the right main bronchus. Thus, a right-sided intubation was performed, and the left main bronchus was obstructed with a bronchial cuff. As a result of the inappropriate ventilation, peak inspiratory pressure was elevated and arterial oxygen saturation decreased.

CONCLUSION

Anesthesiologists should keep in mind the possibility of anatomical variation in the large airways, and bronchoscopy should be accompanied by cautious auscultation and confirmation of the division of the bronchus.

One-Lung Ventilation for Lung Lobectomy Using Endobronchial Blocker Through Adjustable Silicon Hyperflex Tracheostomy Tube in Postlaryngectomy Patient

One-lung ventilation is challenging in patients with difficult airway who require lung surgery. The choice of airway technique remains limited in patients with permanent tracheostomy after total laryngectomy. Conventional airway management techniques and available airway equipment have limited the options for securing airway in such patients, and dedicated airway equipment is not available for the management of such patients. Here, using endobronchial blocker through adult silicon hyperflex tracheostomy tube with an adjustable flange, we report a successful airway management for 1-lung ventilation in a patient with total laryngectomy with permanent tracheostomy.

The Fast and Easy Way for Double-Lumen Tube Intubation: Individual Angle-Modification

To find the faster and easier way than the existing intubating technique for double-lumen tube, we modified the angle of double-lumen tube according to an individual’s upper airway anatomy and compared the time needed and the number of attempts for successful intubation between individually angle-modified and non-modified double-lumen tubes. Adult patients undergoing elective thoracic surgery were randomly allocated in either non-angle-modified (Group N, n = 54) or angle-modified (Group M, n = 54) groups. During mask ventilation in the sniffing position, angle-modification was performed in Group M as follows: the distal tip of the tube was placed at the level of the cricoid cartilage and the shaft was bent at the intersection of the oral and pharyngeal axes estimated from the patient’s surface anatomy. The time needed and the number of attempts for successful intubation and Cormack and Lehane (C-L) grade were recorded. Overall median intubation time (sec) was significantly shorter in Group M than in Group N [10.2 vs. 15.1, P<0.001]. In addition, Group M showed the shorter median intubation time (sec) in C-L grades I-III [8.2 vs. 11.1 in C-L grade I, (P = 0.003), 10.3 vs. 15.3 in II, (P = 0.001), and 11.8 vs. 27.9 in III, (P<0.001), respectively]. Moreover, all intubation was successfully performed at the first attempt in patients with C-L grades I-III in Group M (P = 0.027). Our study showed an individual angle-modification would be useful for the fast and easy intubation of double-lumen tube in patients with C-L grades I-III.

Trial Registration: ClinicalTrials.gov NCT02190032

Experience of hemostasis in tracheal bleeding very close to the carina by the bronchial blocker: a case report

Massive hemoptysis is respiratory compromise which should be managed as a life-threatening condition. In our case, the bronchial blocker played a role in hemostasis of tracheal bleeding very close to the carina and prevented further spillage into the contralateral lung. Right-sided one-lung isolation in an 87-year-old female, who received cardiopulmonary resuscitation due to myocardial infarction, was requested due to hemoptysis. Right-sided bronchial bleeding was suspected on auscultation, but esophageal and tracheal bleeding due to violent intubation with a stylet was also considered. We attempted one-lung isolation with the bronchial blocker. The bronchial blocker was inadvertently advanced to the left mainstem bronchus, but the inflated balloon of the bronchial blocker compressed the site of bleeding, which was within 1 cm proximal and left posterior to the carina. Tracheal bleeding stopped, and we confirmed that hemostasis was achieved with the balloon of the bronchial blocker using a fiberoptic bronchoscope.

Double-lumen tube intubation using video laryngoscopy causes a milder cardiovascular response compared to classic direct laryngoscopy

Objective:

To determine whether there is a clinically relevant difference between the circulatory responses to double-lumen tube intubation (DLTI) with the GlideScope video laryngoscope versus the Macintosh direct laryngoscope.

Methods:

Eighty adult patients requiring double-lumen tubes for thoracic surgery were randomly and equally allocated to either a Macintosh direct laryngoscope group (DL group, n = 40) or a Glide Scope video laryngoscope group (GS group, n = 40). DLTI was performed after airway evaluations and induction of anesthesia. Systolic blood pressure (SBP) and heart rate (HR) were recorded before induction (baseline values), immediately before intubation (post-induction values), at intubation and after intubation. Rate-pressure-product (RPP), and the areas under SBP- and HR-time curves were calculated. All data obtained by the two devices were compared.

Results:

After laryngoscope insertion, SBP of DL and GS groups changed significantly differently (13.1% vs. 4.6%, P< 0.001), while HR changed similarly (17.2% vs. 14.6%, P = 0.074). One minute after intubation, both SBP and HR significantly increased in both groups (SBP: 11.6% vs. 11.9%; HR: 18.4% vs. 10.8%), but there were no significant differences between the two groups. RPP significantly increased in both groups after laryngoscope insertion (32.6%, P=0.001; 18.2%, P=0.002), and there was a significant difference between the two groups (P =0.001). Throughout intubation, the areas under SBP-time curves had a significant difference between the two groups (P = 0.042), while those under HR-time curves did not differ significantly (P=0.06).

Conclusion:

The intubation response was most significant upon laryngoscope insertion during the whole intubation process. The GlideScope video laryngoscope induced milder circulatory fluctuations than the Macintosh direct laryngoscope did, suggesting that DLTI using video laryngoscopy can help reduce the cardiovascular response to intubation.