Clinical Research Directory

High-flow Nasal Cannula Versus Conventional Oxygen During Awake Tracheal Intubation With Difficult Airways

Study Background Airway management is one of the most fundamental and critical technical procedures in anesthesiology, critical care, and emergency medicine. Difficult airway management remains a major challenge in these fields, particularly when a "cannot intubate, cannot ventilate" scenario occurs during the induction of general anesthesia. Such events can rapidly lead to hypoxemia, resulting in brain injury or even death, and have become a significant source of anesthesia-related severe complications and medical disputes. Awake tracheal intubation (ATI) is considered the gold standard for airway management in patients with anticipated difficult airways, as it preserves spontaneous breathing and thereby reduces the risk of catastrophic airway failure during anesthesia induction. However, despite routine supplemental oxygen administration, hypoxemia remains one of the most common and potentially serious complications during ATI. When low-flow oxygen therapy (\<30 L/min) is used, the reported incidence of hypoxemia (SpO₂ ≤ 90%) ranges from 12% to 29%. Once hypoxemia occurs during ATI, it may not only interrupt the procedure, increase the number of intubation attempts, and reduce the likelihood of successful intubation, but also trigger serious cardiovascular events, thereby compromising patient safety. High-flow nasal cannula (HFNC) oxygen therapy can deliver heated and humidified gas at flow rates of up to 70 L/min and improve oxygenation and ventilation through mechanisms such as anatomical dead space washout, reduction of work of breathing, and generation of continuous positive airway pressure. HFNC has been shown to improve oxygenation in a variety of medical and procedural settings. However, evidence regarding the role of HFNC during awake tracheal intubation remains controversial and of low quality. There is an urgent need for well-designed multicenter randomized controlled trials specifically focused on the ATI setting, using hypoxemic events as the primary outcome and applying strictly standardized procedures, to provide high-quality evidence on the effectiveness and safety of HFNC during ATI. Such evidence is essential to inform clinical practice and support future updates of airway management guidelines. Study Hypothesis This study hypothesizes that, in patients with anticipated difficult airways undergoing ATI, HFNC is more effective in preventing intubation-related hypoxemic events than conventional low-flow nasal cannula oxygen therapy. Study Objectives Primary Objective: To evaluate the effectiveness of high-flow nasal cannula oxygen therapy compared with conventional low-flow nasal cannula oxygen therapy in preventing hypoxemia during ATI in patients with anticipated difficult airways. Secondary Objectives: To assess the effects of high-flow nasal cannula oxygen therapy versus conventional low-flow nasal cannula oxygen therapy on procedural outcomes of awake tracheal intubation, including the rate of interventions required after hypoxemia, first-attempt intubation success rate, number of intubation attempts, overall ATI success rate, intubation time, and the incidence of adverse events. Study Methods This study is a multicenter, randomized controlled clinical trial. Adult patients undergoing ATI will be recruited from six tertiary hospitals in China. Participants will be randomly assigned to receive either high-flow nasal cannula oxygen therapy or conventional low-flow nasal cannula oxygen therapy throughout the intubation procedure. The study will compare the incidence of hypoxemia between the two groups and further evaluate intubation success rates, intubation time, the need for rescue interventions following hypoxemia, and the incidence of adverse events.

Comparative Study Between Combined Video Laryngoscope and Video Stylet Intubation Versus Combined Video Laryngoscope and Fiberoptic Intubation in a Simulated Difficult Airway

This study titled "Comparative Study Between Combined Video Laryngoscope and Video Stylet Intubation Versus Combined Video Laryngoscope and Fibreoptic Intubation in a Simulated Difficult Airway" aims to evaluate and compare two advanced intubation techniques used in managing difficult airways. Currently, there is no study in Malaysia that compares the combination of a video laryngoscope (VL) with a video stylet (VS) and the combination of VL with a fibreoptic bronchoscope (FOB). Although both methods have been investigated separately, direct comparisons in simulated difficult airway settings are limited. The findings of this study will help guide airway management protocols and improve clinical outcomes in challenging airway situations. This is a single-centre, randomized comparative crossover trial conducted at the Department of Anaesthesiology and Intensive Care, HCTM, UKM. Ethical approval will be obtained from the departmental and university ethics committees prior to commencement. The study population will consist of anaesthesiology medical officers with at least two years of experience and anaesthesiology trainees in their second to fourth year of training at HCTM, UKM. Participants with severe hand tremors or those who decline participation will be excluded. The main objectives are to compare the first-pass intubation success rate, time to successful intubation, and operator-rated ease of intubation between the two combined techniques. Each participant will perform both VL with VS and VL with FOB intubations in a simulated difficult airway scenario. The study hypothesizes that the combined VL with VS technique will provide superior performance, a higher first-pass success rate, shorter intubation time, and greater ease of use compared to the VL with FOB technique. Participants who fail to complete all procedures or withdraw after participation will be considered dropouts. The results from this study are expected to provide useful insights into the effectiveness and practicality of these two combination techniques for airway management training and clinical application.

Airway Ultrasound vs Clinical Predictors for Difficult Airway

This prospective observational study aims to evaluate the diagnostic value of airway ultrasonography in predicting difficult intubation in adult patients undergoing elective surgery under general anesthesia. Preoperative sonographic measurements of upper airway structures will be compared with conventional clinical airway assessment parameters such as the Mallampati score, thyromental distance, and sternomental distance. The study seeks to determine whether ultrasonographic measurements can serve as independent predictors of difficult airway and whether combining them with clinical parameters improves diagnostic accuracy. Additionally, the correlation between sonographic findings and the Intubation Difficulty Scale (IDS) will be analyzed to assess the potential clinical utility of airway ultrasound in preoperative airway evaluation.

Predicting Difficult Intubation in Bariatric Surgery: Comparison of El Ganzouri Risk Index and Airway Ultrasound

This study is designed as a prospective observational study and will be conducted at the Health Sciences University Antalya Training and Research Hospital. Adult patients scheduled to undergo bariatric surgery will be included. The aim of this study is to compare the El Ganzouri Risk Index (EGRI) and airway ultrasonography (USG) parameters in predicting difficult intubation and to evaluate their relationship with the Cormack-Lehane (CL) score obtained during direct laryngoscopy. Before surgery, each participant will be evaluated using both the EGRI scoring system and airway USG. During general anesthesia, tracheal intubation will be performed using direct laryngoscopy, and data including the CL score, intubation time, number of attempts, and the need for videolaryngoscopy will be recorded based on the anesthesiologist's observations. The collected data will be analyzed by classifying participants according to the presence or absence of difficult intubation, and statistical comparisons will be performed between EGRI scores and airway ultrasonography parameters. The results of this study may contribute to improved preoperative airway assessment and enhanced patient safety in bariatric surgery.

Difficult Airway Incidence in Cardiovascular Surgery and a Prediction Model Development

A difficult airway is a clinical condition that occurs when one or more of the components of difficult mask ventilation, difficult laryngoscopy, difficult endotracheal intubation, difficult supraglottic airway device (SGA) placement, and inability to intubate-oxygenate are present. Data concerning incidence of difficult airway in patients undergoing cardiovascular surgery is controversial. Unwanted hemodynamic changes that may occur in patients undergoing cardiovascular surgery, combined with hemodynamic changes caused by underlying cardiac pathologies, may also lead to a physiologically difficult airway situation. Since all these interactions, combined with the hemodynamic changes caused by difficult airway interventions, may lead to catastrophic outcomes, it is vital to predict difficult airway in this patient population.

Validation of End-to-End Difficult Airway Pathway Planning Algorithm (EAP-LC)

Patients with laryngeal cancer often present with varying degrees of airway narrowing or anatomical distortion, making airway management particularly challenging. Awake flexible bronchoscopic intubation is a widely accepted and important strategy to ensure airway safety in this population. Currently, the selection of the intubation pathway mainly relies on visual assessment of preoperative computed tomography (CT) images and the clinical experience of anesthesiologists, lacking objective and quantifiable tools for airway pathway planning. Our research group has developed an end-to-end airway pathway planning algorithm for laryngeal cancer patients (EAP-LC), which can automatically generate predicted nasal or oral intubation pathways based on preoperative pharyngeal and upper airway CT images. Preliminary simulation analyses based on retrospective CT data demonstrated that the algorithm is capable of identifying airway narrowing and generating trajectories that are close to clinically feasible intubation paths (preliminary data, under review). However, to date, no study has directly compared the algorithm-predicted pathways with actual intubation trajectories obtained during awake flexible bronchoscopic intubation. Therefore, a prospective clinical validation study is required to evaluate the spatial consistency and clinical feasibility of the EAP-LC algorithm. Without altering routine clinical treatment or anesthetic management, this study aims to evaluate the clinical accuracy, safety, and feasibility of the EAP-LC algorithm by comparing the intubation pathways predicted from preoperative CT images with the real-world trajectories recorded during awake flexible bronchoscopic intubation. The results of this study are expected to provide a more precise and objective decision-support tool for airway management in patients with laryngeal cancer.

SEALion: Study on Supplemental Oxygenation Via Nasal Cannula for Young Children During Intubation

Tracheal intubation in neonates can be technically challenging, even for experienced pediatric anesthesiologists, with a high first-attempt success rate crucial to ensure safety. Intubation, while life-saving for children with circulatory shock or respiratory failure, carries risks of severe desaturation that can lead to hypoxic encephalopathy, cardiac arrest, or death. Neonates, especially, are prone to hypoxemia due to high oxygen consumption, low functional residual capacity, small closing capacity, and increased risk of airway collapse, which is exacerbated under anesthesia and neuromuscular paralysis. Rapid desaturation occurs after cessation of ventilation, with neonates facing shorter apnea times before desaturation. Studies show that about two-thirds of neonates undergoing non-emergency nasotracheal intubation experience desaturation (SpO₂ \<80% for over 60 seconds), although low-flow oxygen supplementation (0.2 L/kg/min) can extend safe apnea time. This study aims to investigate apneic oxygenation with VL (using Miller or Macintosh blades size 0 or 1) in operating rooms or intensive care units. We hypothesize that supplemental oxygen and standardized VL use will improve first-pass success rates and reduce adverse events.

Determination of the Frequency and Predictors of Difficult Intubation in Septoplasty Operations

Deviated septum is among the most prevalent etiologies of nasal obstruction. Congenital or acquired deformities of the nasal septum have been demonstrated to result in partial obstruction of the airflow, thereby causing respiratory distress. Furthermore, studies have indicated a potential correlation between nasal congestion and Obstructive Sleep Apnoea Syndrome (OSAS). It is a well-documented phenomenon that patients suffering from nasal obstruction often exhibit an open mouth during sleep, a condition that has been shown to result in the narrowing of the pharyngeal lumen and the subsequent development of sleep-related breathing disorders, including snoring and sleep apnoea. Surgical intervention to correct a deviated nasal septum (commonly referred to as septoplasty) has been shown to reduce upper airway resistance by enhancing airflow, leading to a reduction in the severity of both snoring and OSAS. Numerous studies have demonstrated a robust correlation between a deviated nasal septum and asymmetric facial growth, including maxillary and mandibular abnormalities. While septoplasty is considered a minor surgical procedure with a low anaesthetic risk, concomitant obstructive sleep apnoea syndrome (OSAS) and facial asymmetry have been demonstrated to be associated with an increased risk of difficult intubation. Consequently, the development of preoperative assessment tests to predict difficult intubation is imperative for effective planning of the necessary preoperative preparation when such complications are anticipated. The present study therefore sought to evaluate the incidence of difficult airway in patients undergoing septoplasty. The secondary aim was to determine the predictive factors associated with difficult airway in patients undergoing septoplasty.

AI-based Prediction Model of Difficult Tracheal Intubation Using Medical Image Parameters

Difficult airway is a life-threatening event during anesthesia. Prediction model is helpful to detect high-risk patients and decrease the risk of un-anticipated difficult airway. Present models are usually based on Mallampati grade and the width of mouth open. However, the prediction accuracy is only about 0.7-0.8 in different populations. Present study is designed to investigate if AI-based prediction model using medical imaging parameters (such as CT and MRI) can increase the accuracy of prediction model.

Using Ultrasound for Bougie Insertion in Difficult Airway Management

Difficult airway management remains one of the biggest challenges in anesthesia practice. The Gum elastic bougie, an intubation tool, is frequently used to facilitate intubation in difficult situations. Recently, ultrasound-guided airway management has been used as a potential method to improve the intubation process. This study aims to compare the efficacy of ultrasound-guided bougie insertion with the conventional method regarding the duration of endotracheal tube (ETT) insertion and the number of attempts required in a difficult intubation population. The goal of this clinical trial is to learn if using ultrasound during bougie insertion in difficult airway patients will improve the success rate and reduce the time of insertion. The main questions it aims to answer are: Does using ultrasound reduce the number of insertion attempts? Does using ultrasound reduce the duration of bougie insertion? Researchers will compare the ultrasound-guided technique to the conventional bougie insertion method. They will also assess both groups' hemodynamic parameters during and after the procedure and the success rate from the first trial.

Comparison of Two Sedation Regimens for Awake Fiberoptic Intubation

The purpose of this study is to examine the effects of different sedation drugs used for the awake fiberoptic intubation procedure. Benzodiazapines and narcotics (such as midazolam and fentanyl) are standard drugs used for sedation during awake fiberoptic intubation. Dexmedetomidine, midazolam, and fentanyl are approved by the Food and Drug Administration (FDA) procedural sedation. These drugs might be given to the patient regardless of their participation in the study. In addition to midazolam and fentanyl study subjects will also receive either dexmedetomidine or a placebo (a salt solution that contains no drug). It is believed that dexmedetomidine will not slow down breathing as much as the combination of the valium-like drug and narcotic. In our study, we are trying to determine if this is the best drug for sedation during an awake fiberoptic procedure.

Ultrasound Airway Examination as a Tool for Detection of Difficult Intubation in Adult Patients

the goal of the observational study to measure the effectiveness of neck ultrasound in prediction of difficult intubation in adult patients

Sevoflurane Sedation as an Alternative for Awake Fiberoptic Intubation in Difficult Airway Patients

The aim of this study is to compare patient satisfaction and intubating conditions with fiber optic intubation under sevoflurane sedation versus airway blocks in difficult airway patients

Postoperative Memories and Level of Sedation for Tracheal Intubation Using Fiberoptic Bronchoscopy/Videolaryngoscopy

Antecedentes In patients with expected difficult airways undergoing surgery, tracheal intubation must be performed with a fiberoptic bronchoscope or video laryngoscope while keeping the patient awake and under the effects of anesthetic sedation. Objective: To determine and compare the existence of postoperative memories of the patients and the different levels of sedation (Ramsay scale) obtained during the intubation procedure. Methods Prospective observational study that includes 100 patients older than 18 years who are going to undergo surgery, who need fiberoptic bronchoscopy/videolaryngoscopy for tracheal intubation due to the planned difficult airway and intravenous sedation. Patients with an unexpected difficult airway, under 18 years of age and/or with cognitive impairment will be excluded. After checking the tracheal intubation, the general anesthesia indicated for each patient will be used. Twenty-four hours after tracheal extubation, the patient will be questioned about the pain presented during the fiberoptic bronchoscopic/videolaryngoscopic procedure and postoperative memories based on a modified Brice questionnaire. At 30 days after surgery, the postoperative memories of the patients will be evaluated again by telephone interview.