Difficult Airway Intubation

Tracheal intubation in paediatric patients is a high-risk procedure in which failure to achieve successful intubation on the first attempt is associated with an increased risk of complications, including hypoxaemia and airway trauma. Videolaryngoscopes have been increasingly adopted in clinical practice because they improve glottic visualisation; however, evidence of their benefit in paediatric patients remains inconsistent. The VIDEOKIDS trial is a large, pragmatic, international, multicentre, randomised controlled trial designed to compare videolaryngoscopy with direct laryngoscopy as the initial technique for tracheal intubation in paediatric patients undergoing surgery under general anaesthesia. The primary objective is to determine whether videolaryngoscopy increases the rate of successful intubation on the first attempt compared with direct laryngoscopy.

Obesity is associated with anatomical changes in the upper airway that increase the risk of difficult laryngoscopy and difficult mask ventilation during anesthesia. Conventional airway assessment parameters such as Mallampati score, neck circumference, and STOP-BANG scale are widely used but have limited predictive accuracy in obese patients. Airway ultrasonography has emerged as a promising non-invasive tool for difficult airway prediction; however, ultrasonographic criteria have not yet been standardized. This prospective observational study aims to evaluate the utility of airway ultrasonography in predicting difficult airway in adult obese patients (BMI \>30 kg/m²) scheduled for elective surgery under general anesthesia. Ultrasonographic measurements will include the distance from skin to hyoid bone (DSHB) at the level of the hyoid bone, the anterior neck soft tissue thickness at the thyrohyoid membrane level, and the hyomental distance ratio (HMDR). These parameters will be compared with conventional airway assessment tools and correlated with intraoperative Cormack-Lehane laryngoscopy grade and Han Scale mask ventilation score to determine their predictive value for difficult airway.

This prospective observational study aims to evaluate whether upper airway ultrasound measurements can improve the prediction of difficult airway compared with conventional anthropometric assessments. Adult patients undergoing elective procedures requiring airway management will be included. Ultrasound parameters such as tongue thickness, anterior neck soft tissue thickness, and hyomental distance will be measured before airway intervention. Standard clinical predictors (Mallampati score, thyromental distance, neck circumference, etc.) will also be recorded. The primary objective is to determine the diagnostic accuracy of ultrasound-based measurements in predicting difficult laryngoscopy and intubation. The study seeks to provide evidence supporting the integration of upper airway ultrasound into routine pre-anesthetic airway evaluation.

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.

1. Study Purpose This research aims to develop a novel, non-invasive, and simple method to predict difficult intubation before surgery. The core idea is that the anatomy of a person's throat and mouth, which determines the ease of intubation, also uniquely shapes their voice. By analyzing the acoustic features of specific vowel sounds using machine learning, we seek to identify voice patterns associated with difficult airways. The ultimate goal is to create a tool that allows for a quick, painless pre-operative risk assessment, enhancing patient safety by better preparing anesthesiologists. 2. Study Design This is a prospective, observational, single-center study. It is purely observational and does not involve any changes to standard medical care or anesthesia procedures. 3. Participants We plan to enroll 300 patients. Who can join: Patients aged 15-70 scheduled for elective surgery requiring general anesthesia with tracheal intubation. Who cannot join: Individuals with speech/hearing impairments, significant neurological diseases affecting speech, or conditions contraindicating standard laryngoscopy. 4. Study Procedures For participants, the study involves one key procedure in addition to standard care:Voice Recording: Before surgery, participants will be asked to lie down and pronounce the vowels "a," "e," and "i" steadily for 1-2 seconds. This will be done twice: once with the head in a normal position and once with the head tilted back. A high-quality recorder will capture the sounds. This process is painless and takes only a few minutes. Standard anesthesia and intubation will then proceed as usual. The anesthesiologist will record the laryngeal view obtained during intubation, which will be used to classify the case as "difficult" or "non-difficult" for analysis. 5. Data Analysis The primary goal is to determine if there are statistically significant differences in the key voice resonance frequencies (F1, F2, F3) between the difficult and non-difficult intubation groups. Advanced machine learning models will be built to create the predictive algorithm. 6. Risks and Benefits Benefits: There is no direct medical benefit to participants. The contribution is to future medical knowledge and patient safety. Risks: The study involves minimal risk. The voice recording is non-invasive and safe. The main risk is the potential loss of confidentiality, which is mitigated by strict data protection protocols. 7. Confidentiality \& Ethics All patient data will be de-identified and stored securely. The study protocol and informed consent form have been approved by the Institutional Ethics Committee of Shanghai Sixth People's Hospital. Participation is voluntary, and participants may withdraw at any time without affecting their medical care. Written informed consent will be obtained from every participant before any study procedures.

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.

This prospective observational study aims to evaluate three scoring systems (VIDIAC (Video Laryngoscopic Intubation and Difficult Airway Classification), PeDiAC (Pediatric Difficult Airway Classification), and the Intubation Difficulty Scale (IDS)). A total of 450 children undergoing general anesthesia with videolaryngoscopic intubation will be included in the study. Demographic data, intraoperative parameters, and glottic imaging, as well as detailed intubation-related variables such as total intubation time, number of attempts, complications, and subjective intubation ease scores will be recorded.