Airway Anatomy Research Articles

Evaluation of thyromental distance versus tongue width versus weight-based method for size determination of laryngeal mask airway in adults

Background: Supraglottic airway devices (SGD) are indispensable for airway management. The successful placement of the laryngeal mask airway (LMA) supreme largely depends on the right size selection. Aims and Objectives: The study was undertaken to compare three LMA supreme insertion methods in short elective surgeries under general anesthesia. Materials and Methods: Atotal of 90 American Society of Anesthesiologists I and II patients (either gender, 18–55 years, Mallampati grade I and II) undergoing short surgeries were randomized into three equal groups (n=30 in each). Insertion of LMA was done after an adequate depth of anesthesia for jaw relaxation (Young’s criteria). The efficacy of controlled ventilation through LMA by each method, success rate, ease of insertion, insertion time, additional induction dose (propofol) required during insertion, hemodynamic stability (baseline vitals and 10 min after insertion), and adverse events after LMA removal were evaluated between groups. Results: Better ventilation (tidal volume at 10 cmH2O) was observed in the thyromental group (448±35) than in tongue width (440±46) and weight-based (409±33) groups. Minimum additional propofol requirement during insertion was in thyromental distance group. Thyromental distance group had the most easy LMA insertions (70%) with minimum insertion time (10±4) and minimum additional propofol requirement during insertion (P<0.05) than other groups. Overall hemodynamic stability and incidence of adverse events were comparable. Conclusion: Thyromental distance may be an alternative attractive choice for size determination of LMA supreme in female adults with normal airway anatomy in comparison to tongue width and conventional body weight-based methods.

Mechanisms relating to sleeping position to the endotypes of sleep disordered breathing.

Obstructive sleep apnea (OSA) severity varies considerably depending on the body position during sleep in certain subjects. Such variability may be underpinned by specific, body position-related changes in OSA pathophysiological determinants, or endotypes. Also head position relative to trunk may influence OSA endotypes. However, no studies to our knowledge have reviewed the endotype variations according to head or body position up to now. Several findings illustrate that supine OSA is mostly attributable to unfavorable upper airway anatomy compared to lateral position. However, a reduced lung volume, with consequent ventilatory instability (or elevated loop gain), may also play a role. Furthermore, preliminary findings suggest that prone and reclined positions may have a beneficial effect on collapsibility and loop gain. Sleeping supine induces many unfavorable pathophysiological changes, especially in certain predisposed OSA patients. Little is known on the influence of other sleep positions on key endotypic traits.

Virtual reality and 3D printing in clinical anesthesia: a case series of two years' experience in a single tertiary medical centre.

Anatomically correct patient-specific models made from medical imaging can be printed on a three-dimensional (3D) printer or turned into a virtual reality (VR) program. Until recently, use in anesthesia has been limited. In 2019, the anesthesia department at Tel Aviv Medical Center launched a 3D program with the aim of using 3D modelling to assist in preoperative anesthesia planning. A retrospective review of all relevant patients between July 2019 and June 2021 referred for preoperative airway planning with 3D modelling. Patient files were reviewed for correlation between the model-based airway plan and the actual airway plan, the type of model used, and any anesthetic complications related to airway management. Twenty patients were referred for 3D modelling. Of these, 15 models were printed, including 12 children requiring one lung ventilation. Five patients had VR reconstructions, including three with mediastinal masses. One patient had both a 3D-printed model and a VR reconstruction. There were two cases (10%) where the model plan did not correlate with the final airway plan and one case where a model could not be created because of poor underlying imaging. For the remaining 17 cases, the plan devised on the model matched the final airway plan. There were no anesthetic complications. Three-dimensional modelling and subsequent printing or VR reconstruction are feasible in clinical anesthesia. Its routine use for patients with challenging airway anatomy correlated well with the final clinical outcome in most cases. High-quality imaging is essential.

Continuous Positive Airway Pressure plus Mandibular Advancement Therapy (PAPMAT): study protocol for an adaptive randomised crossover trial comparing the benefits and costs of combining two established treatments for obstructive sleep apnoea

BackgroundObstructive sleep apnoea (OSA) involves repeated breathing pauses during sleep due to upper airway obstruction. It causes excessive daytime sleepiness and has other health impacts. Continuous positive airway pressure (CPAP) therapy is effective first line treatment for moderate to severe OSA. Unfortunately, many patients have difficulty tolerating CPAP and pressure intolerance is probably an important contributing factor. Mandibular advancement devices (MAD) are an alternative to CPAP. They are worn in the mouth during sleep to reduce airway obstruction. There is some evidence that, when used in combination with CPAP, MADs improve airway anatomy enough to reduce the CPAP pressure required to treat OSA and that this combination therapy could improve CPAP adherence.MethodsConsecutive patients starting on CPAP for moderate to severe OSA will be recruited at a regional NHS sleep service. Patients with high CPAP pressure requirements after initial titration, who satisfy all entry criteria and consent to participate, will undertake a 2-arm randomised crossover trial. The arms will be (i) standalone CPAP and (ii) CPAP + MAD therapy. Each arm will last 12 weeks, including 2 weeks acclimatisation. CPAP machines will be auto-titrating and with facility for data download, so the impact of MAD on CPAP pressure requirements and CPAP adherence can be easily measured. The primary outcome will be CPAP adherence. Secondary outcomes will include measures of OSA severity, patient-reported outcome measures including subjective daytime sleepiness, quality of life, and treatment preference at the trial exit and health service use. Cost-effectiveness analyses will be undertaken.DiscussionIf the intervention is shown to be effective and cost-effective in improving adherence in this standard CPAP-eligible OSA patient population it would be relatively straightforward to introduce into existing OSA treatment pathways, within the wider NHS and more widely. Both MAD and CPAP are already used by sleep services so their combination would require only minor adjustments to existing clinical pathways. It would be straightforward to disseminate the results of the study through regional, national, and international respiratory meetings. The health economics analysis would provide cost-effectiveness data to inform service planning and clinical guidelines through policy briefing papers, including those by NICE and SIGN.Trial registrationPAPMAT was registered with ISRCTN prior to recruitment beginning (ISRCTN Registry 2021): https://www.isrctn.com/ISRCTN33966032. Registered on 17th November 2021.

Facial Contour Features Measured on CT Reflects Upper Airway Morphology in Patients With OSA.

To determine facial contour features, measured on computed tomography (CT), related to upper airway morphology in patients with obstructive sleep apnea (OSA); certain phenotype of facial abnormalities implying restriction of craniofacial skeleton and adipose tissue nimiety has predicted the value of the severity of OSA. Sixty-four male patients with OSA [apnea-hypopnea index (AHI) ≥10/h] who had upper airway CT were randomly selected to quantitatively measure indicators of facial contour and upper airway structures. Pearson correlation analyses were performed. Partial correlation procedure was used to examine correlations while controlling body mass index (BMI). Upper airway anatomy can nearly all be reflected in the face, except retroglossal airway. Upper face width can be measured to assess the overall skeletal structures of the airway. Lower face width can be used to represent how much adipose tissue deposited. Hard palate, retropalatal, and hypopharyngeal airways have corresponding face indicators respectively. Midface width is a better predictor of AHI severity and minimum blood oxygen even than neck circumference because it contains the most anatomical information about the airway, including RP airway condition, soft palate length, tongue volume, etc. These correlations persisted even after correction for BMI. All anatomical features of the upper airway except retroglossal airway can be reflected in the face, and midface width is the best predictor of AHI severity and minimum blood oxygen, even better than neck circumference and BMI.

Comparison of the Airway Anatomy between Infants and Three Pediatric Simulators: A Radiological Study on Premature Anne, Infant AM Trainer and Simbaby Manikins

Background: Training is required to achieve proficiency in airway management. Simulators are of utmost importance not only for the purpose of training novices, but also for evaluating newer airway devices and techniques. Growing evidence supports inadequate anatomic airway reproduction in adult and pediatric manikins. Methods: We conducted an observational study comparing 17 radiological anatomic airway measurements obtained via the computed tomography of three commercially available manikins with the same measurements obtained from a population of newborns/infant (range: 0–3 months) undergoing magnetic resonance imaging for diagnostic purposes. According to the reference (mean and standard deviation (SD) of the pediatric population), each manikin measurement was defined as adequate, partially adequate or inadequate (difference between means: ≤±1, 1.0–1.96 or >1.96 SD, respectively). The primary outcome was the number of measurements with an adequate reproduction of airways. Results: We included 27 pediatric patients (21 ± 19 days, 48% males, 46.6 ± 3.5 cm, 2.7 ± 0.5 Kg and 12.6 ± 2.9 kg/m2). All manikins had n = 11/17 measurements with inadequate airway anatomic reproduction. The three measurements with more adequate reproduction were the height of the soft palate, retropalatal airspace volume and tongue volume (adequate in two manikins, and partially adequate in the remaining one). Conclusions: In three manikins commonly used for training in pediatric airways, static dimensions do not seem anatomically correct in relation to those of pediatric patients. Such inaccuracies may introduce biases in airway device development as well as in training.

Computational fluid dynamics can detect changes in airway resistance for patients after COVID-19 infection

Infection with COVID-19 can cause severe complication in the respiratory system, which may be related to increased respiratory resistance. Computational fluid dynamics(CFD) was used in this study to calculate the airway resistance based on the airway anatomy and a common air flowrate. The correlation between airway resistance and COVID-19 prognosis was then investigated. A total of 23 COVID-19 patients with 54 CT scans were grouped into the good prognosis and bad prognosis group based on whether the CT scan shows significant decrease in the pneumonia volume after one week treatment and retrospectively analyzed. A baseline group of 8 healthy people with the same age and gender ratio is enrolled for comparison. Results show that the airway resistance at admission is significantly higher for COVID-19 patients with poor prognosis than those with good prognosis and the baseline(0.063 ± 0.055 vs 0.029 ± 0.011 vs 0.017 ± 0.006 Pa/(ml/s),p = 0.01). In the left superior lobe (r = 0.3974,p = 0.01),left inferior lobe (r = 0.4843,p < 0.01), the right inferior lobe (r = 0.5298,p < 0.0001), the airway resistance was significantly correlated with the degree of pneumonia infection. It is concluded that for COVID-19 patients’, airway resistance at admission is closely associated with their prognosis, and has the clinical potential to be used as an index for patients’ diagnosis.

0450 Backscattered Ultrasound Imaging of the Tongue Correlates with Severity of Obstructive Sleep Apnea in Adults

Abstract Introduction Determination of intervention to manage obstructive sleep apnea (OSA) is dependent on clinical examination, polysomnography results, and imaging analysis. There remains the need of a non-invasive and cost-effective way to correlate relevant upper airway anatomy with severity of obstructive sleep apnea (OSA ) to direct treatment and optimize outcome. We aimed to determine whether ultrasonography with backscattered imaging (BUI) analysis of the tongue correlates with severity of OSA in adults. Methods A prospective, single-center, observational study of a consecutive series of patients (aged18 years and older) visiting our sleep clinic. All included patients had a polysomnography (PSG) within 3 years from the moment of BUI analysis. Patients were excluded if their BMI had changed more than 10%. We used and standardized the submental ultrasound scan with a laser alignment tool and applied BUI analysis to the tongue. Outcomes were correlated to the patients’ AHI, BUI results were compared to only echo intensity. Results Eighty-nine patients were included between July 2020 and March 2022. Mean age was 38.8±12.7 years, mean BMI was 26.7±5.0 kg/m2, and mean AHI was 17.5±16.8 events/h. Significant differences were found between the subgroups with AHI&amp;lt; 15 and □15 events/h at specific regions of the tongue base using BUI analysis, echo intensity showed no significant differences. BUI values showed a positive correlation with AHI, with Pearson correlation coefficient of 0.42 and 0.37, and Spearman correlation coefficient of 0.43 and 0.43 for the A and B regions of the tongue, respectively. Higher BUI values are associated with more severe AHI, even after correction for covariates (BMI and age). Conclusion Standardized ultrasound scanning of the tongue with backscattered imaging analysis yields strong correlation with severity of OSA. With the intrinsic advantages in the use of ultrasonography in outpatient settings, this analysis is pivotal in reducing the gap between anatomy and physiology in clinical decision-making for treating OSA. Support (if any) None

0797 Correlation between Obstructive Sleep Apnea and Echocardiography Parameters in Infants and Preschool Children with Down Syndrome

Abstract Introduction Down syndrome (DS) is one of the most common genetic disorders caused by the Trisomy of chromosome 21. Children with DS secondary to the unique airway anatomy and hypotonia, are at risk for obstructive sleep apnea (OSA). Untreated OSA in children can lead to serious complications because of chronic hypoxia leading to Pulmonary hypertension (PHTN) and Cor pulmonale. An overnight polysomnogram (PSG), the gold standard for diagnosing OSA in children, should be performed within 4 years per American Academy of Pediatrics recommendations. However, OSA in DS has been observed at a much younger age. Methods In this single-center retrospective study, data was collected by reviewing the medical records and PSG REDCap database from 2019-2021. Patients with ICD code 10 diagnosis of DS between 0 to 4 years of age who underwent PSG and echocardiography were included. Our primary aim was to assess the severity of OSA in preschool children and describe echocardiogram parameters in DS patients with OSA. We hypothesized that there will be differences in polysomnogram parameters of DS children with and without PHTN. Results 61 patients met the criteria for the study with the mean age being 11.3 months. 3 patients (5.4%) did not have OSA (apnea hypopnea index (AHI)&amp;lt; 1/hr), 11 patients (19.6%) had mild OSA (AHI 1-4.9/hr), 12 patients (21.4%) had moderate OSA (AHI 5-10/hr), 30 patients had severe OSA (AHI &amp;gt;10/hr). Five patients with missing AHI values were excluded for subsequent analyses. Echocardiogram parameters were compared using the described AHI cut offs to define severity of OSA. OSA was observed to be significantly higher in the group with elevated RV systolic pressure. Conclusion Although our study did not find any difference in PSG findings in young children with DS with and without PHTN, obstructive apnea index was significantly elevated in young children with elevated RV systolic pressure. OSA is a significant contributor to the development of PHTN in children with DS. Children with DS are at higher risk for PHTN due to their unique pulmonary vasculature. As PHTN is a significant comorbidity of DS, it is important to perform PSGs early during childhood to detect and treat OSA. Support (if any)

Approach to the Physiologically Challenging Endotracheal Intubation in the Intensive Care Unit.

Endotracheal intubation for airway management is a common procedure in the ICU. Intubation may be difficult due to anatomic airway abnormalities but also due to physiologic derangements that predispose patients to cardiovascular collapse during the procedure. Results of studies demonstrate a high incidence of morbidity and mortality associated with airway management in the ICU. To reduce the likelihood of complications, medical teams must be well versed in the general principles of intubation and be prepared to manage physiologic derangements while securing the airway. In this review, we present relevant literature on the approach to endotracheal intubation in the ICU and provide pragmatic recommendations relevant to medical teams performing intubations in patients who are physiologically unstable.

Global research trends in prediction of difficult airways: A bibliometric and visualization study.

Many tools are used to predict difficult airway, including bedside screening tests, radiological variables, and ultrasonography. However, the "gold standard" to identify difficult airway before intubation has not been established. The assessment and prediction of difficult airway is receiving increasing attention in clinical practice due to the devastating results of failed oxygenation or intubation. A literature visualization study is necessary to understand the research trend and help tailor future research directions. Science citation index-expanded web of Science database were used to search for literature related to assessment and prediction of difficult airways published before May 9th, 2022. VOS viewer software was used for visual analysis, including literature statistics, and co-occurrence analysis. A total of 2609 articles were included. The amount of relevant research interest and literature is increasing every year. According to co-occurrence network analysis, the research results can be grouped into the following 5 clusters, intubation approaches, intubation in special populations, difficult airway assessment tests, intubation in critical care/emergency settings and education, and laryngoscopes. Co-occurrence overlay analysis showed that video laryngoscopes and index prediction (including computed tomography and ultrasonography), emerged recently and comprised an important percentage of current studies. It can be predicted that future studies should focus on understanding the upper airway anatomy and constructing risk index predictions. Based on current global research trends, risk index predictions are the next hot topics in the evaluation and prediction of difficult airways, and video laryngoscopes will continue to be a hot topic in this field.

Association of Backscattered Ultrasonographic Imaging of the Tongue With Severity of Obstructive Sleep Apnea in Adults

Determining interventions to manage obstructive sleep apnea (OSA) depends on clinical examination, polysomnography (PSG) results, and imaging analysis. There remains the need of a noninvasive and cost-effective way to correlate relevant upper airway anatomy with severity of OSA to direct treatment and optimize outcome. To determine whether backscattered ultrasonographic imaging (BUI) analysis of the tongue is associated with severity of OSA in adults. In this prospective, single-center, diagnostic study of a consecutive series of patients (aged ≥18 years) at a sleep surgery clinic, the 89 included patients had a PSG within 3 years at the time of ultrasonography and BUI analysis between July 2020 and March 2022. Patients were excluded if body mass index had changed more than 10% since time of PSG. A standardized submental ultrasonographic scan with laser alignment was used with B-mode and BUI analysis applied to the tongue. The B-mode and BUI intensity were associated with the apnea-hypopnea index (AHI), a measure of severity of apnea from normal (no OSA) to severe OSA. Ultrasonography and PSG. The main outcomes were BUI parameters and their association with AHI value. Eighty-nine patients were included between July 2020 and March 2022. A total of 70 (78.7%) male patients were included; and distribution by race and ethnicity was 46 (52%) White participants, 22 (25%) Asian participants, and 2 (2%) African American participants, and 19 (21%) others. Median (IQR) age was 37.0 (29.0-48.3) years; median (IQR) BMI was 25.3 (23.2-29.8); and median (IQR) AHI was 11.1 (5.6-23.1) events per hour. At the middle to posterior tongue region, the 4 OSA severity levels explained a significant portion of the BUI variance (η2 = 0.153-0.236), and a significant difference in BUI values was found between the subgroups with AHI values of less than 15 (no OSA and mild OSA) and greater than or equal to 15 (moderate OSA and severe OSA) events per hour. The echo intensity showed no significant differences. The BUI values showed a positive association with AHI, with a Spearman correlation coefficient of up to 0.43. Higher BUI values remained associated with higher AHI after correction for the covariates of BMI and age. In this prospective diagnostic study, standardized BUI analysis of the tongue was associated with OSA severity. With the practicality of ultrasonography, this analysis is pivotal in connecting anatomy with physiology in treatment planning for patients with OSA.

Point-of-Care Ultrasound in Airway Evaluation and Management: A Comprehensive Review.

Airway management is a common and critical procedure in acute settings, such as the Emergency Department (ED) or Intensive Care Unit (ICU) of hospitals. Many of the traditional physical examination methods have limitations in airway assessment. Point-of-care ultrasound (POCUS) has emerged as a promising tool for airway management due to its familiarity, accessibility, safety, and non-invasive nature. It can assist physicians in identifying relevant anatomy of the upper airway with objective measurements of airway parameters, and it can guide airway interventions with dynamic real-time images. To date, ultrasound has been considered highly accurate for assessment of the difficult airway, confirmation of proper endotracheal intubation, prediction of post-extubation laryngeal edema, and preparation for cricothyrotomy by identifying the cricothyroid membrane. This review aims to provide a comprehensive overview of the key evidence on the use of ultrasound in airway management. Databases including PubMed and Embase were systematically searched. A search strategy using a combination of the term "ultrasound" combined with several search terms, i.e., "probe", "anatomy", "difficult airway", "endotracheal intubation", "laryngeal edema", and "cricothyrotomy" was performed. In conclusion, POCUS is a valuable tool with multiple applications ranging from pre- and post-intubation management. Clinicians should consider using POCUS in conjunction with traditional exam techniques to manage the airway more efficiently in the acute setting.

Mandibular Advancement Device Effects on the Upper Airway Anatomy and Function: An Umbrella Review

Mandibular Advancement Device Effects on the Upper Airway Anatomy and Function: An Umbrella Review

Point-of-Care Ultrasound: A Review of Ultrasound Parameters for Predicting Difficult Airways.

Airway management remains a crucial part of perioperative care. The conventional approach to assessing potentially difficult airways emphasizes the LEMON method, which looks for and evaluates the Mallampati classification, signs of obstruction, and neck mobility. Clinical findings help predict a higher likelihood of difficult tracheal intubation, but no clinical result reliably excludes difficult intubation. Ultrasound as an adjunct to clinical examination can provide the clinician with a dynamic anatomical airway assessment, which is impossible with clinical examination alone. In the hands of anesthesiologists, ultrasound is becoming more popular in the perioperative period. This method is particularly applicable for identifying proper endotracheal tube positioning in specific patient populations, such as those who are morbidly obese and patients with head and neck cancer or trauma. The focus is on identifying the normal anatomy, correctly positioning the endotracheal tube, and refining the parameters that predict difficult intubation. Several ultrasound measurements are clinical indicators of difficult direct laryngoscopy in the literature. A meta-analysis revealed that the distance from the skin to the epiglottis (DSE) is most associated with a difficult laryngoscopy. An ultrasound of the airway could be applied in routine practice as an adjunct to the clinical examination. A full stomach, rapid sequence intubation, gross visual anatomical abnormalities, and restricted neck flexibility prevent using ultrasound to assess the airway. The airway evaluation is performed with a linear array transducer of 12-4 MHz, with the patient in the supine position, with no pillow, and with the head and neck in a neutral position. The central axis of the neck is where the ultrasound parameters are measured. These image acquisitions guide the standard ultrasound examination of the airway.

How to Build a Low-Cost Video-Assisted Laryngoscopy Suite for Airway Management Training.

This suite of borescope laryngoscopes is designed to instruct emergency medicine residents and sub-interns in video-assisted airway management. Skillful and confident airway management is one of the markers of a strong emergency medicine physician.1 Video-assisted airway management is a necessary skill, particularly in the setting of difficult airways and cervical spine immobilization.2,3 However, the idea of learning airway management "by doing" is high-risk and mistakes can have devastating implications on patient outcomes. Fortunately, high-fidelity medical simulation tools have been developed to address this dilemma, allowing a safe environment for providers to practice their airway management skills.4,5 These tools, while undeniably useful, are limited in their scope; they are often designed for clinical rather than educational use, and are proprietary and expensive.6,7Video laryngoscopes approved for patient use are difficult to implement widely in educational settings due to cost or because they cannot be removed from a designated area. Clinical video laryngoscopy suites typically cost 2,000 - 6,000 US dollars. Additionally, the video images can only be viewed on a local small screen rather than a television or projector. This means that the number of learners is limited by space around the small laryngoscope screen. These cost and space barriers may be especially pronounced in low resource or non-traditional learning environments. Using an anatomically accurate airway simulator, by the end of a 20-30-minute instructional session, learners should be able to: 1) Understand proper positioning and use the video laryngoscope with dexterity, 2) identify airway landmarks via the video screen, and 3) demonstrate ability to intubate a simulated airway. We developed a low-cost borescope laryngoscope for airway simulation training. Using this device, learners should be able to identify airway landmarks and successfully intubate a simulated airway. The borescope laryngoscope, a novel device which employs the camera-end of a video borescope and a single-use VL blade, was used by learners during high-fidelity airway simulation. Learners were residents or medical students undergoing airway training in case-based simulation, or in airway-management procedure stations. The borescope laryngoscopes were used during dedicated airway training in place of their medical device counterparts. During case-based simulation sessions involving airway management, 32 residents and 20 medical students used the borescope laryngoscope. During dedicated airway management procedure stations, 12 medical students used the borescope laryngoscope. Learners were instructed to perform endotracheal intubation and fully visualize critical structures before passing the tube. Successful intubation was defined as the ability to pass the tube independently or with the help of the instructor. The borescope laryngoscope proved effective at video visualization of critical structures. Compared to official medical equipment, the VL borescope similarly allowed for visualization of a Cormack-Lehane Grade 1 view. Learners were able to visualize the airway anatomy and successfully pass the ET tube on each pass either independently or with the help of the instructor. The development of this airway-training tool was effective and less expensive than medical grade versions. Our group of learners successfully visualized essential anatomy and passed an endotracheal tube (ED tube) through the vocal cords. The borescope laryngoscope offers a comparable user experience at a much lower cost. The devices also allowed instructors to teach video laryngoscopy without depending on clinical equipment. Widespread use may allow for expansion of airway simulation training while maintaining a high-fidelity learner experience. Video laryngoscopy, borescope, improvised equipment, airway training.

Oronasal vs Nasal Masks: The Impact of Mask Type on CPAP Requirement, Pharyngeal Critical Closing Pressure (Pcrit), and Upper Airway Cross-Sectional Areas in Patients With OSA

CPAP delivered via an oronasal mask is associated with lower adherence, higher residual apnea-hypopnea index (AHI), and increased CPAP therapeutic pressure compared with nasal masks. However, the mechanisms underlying the increased pressure requirements are not well understood. How do oronasal masks affect upper airway anatomy and collapsibility? Fourteen patients with OSA underwent a sleep study with both a nasal and oronasal mask, each for one-half of the night (order randomized). CPAP was manually titrated to determine therapeutic pressure. Upper airway collapsibility was assessed using the pharyngeal critical closing pressure (Pcrit) technique. Cine MRI was done to dynamically assess the cross-sectional area of the retroglossal and retropalatal airway throughout the respiratory cycle with each mask interface. Scans were repeated at 4cm H2O and at the nasal and oronasal therapeutic pressures. The oronasal mask was associated with higher therapeutic pressure requirements (ΔM ± SEM;+2.6 ± 0.5; P< .001) and higher Pcrit (+2.4 ± 0.5cm H2O; P= .001) compared with the nasal mask. The change in therapeutic pressure between masks was strongly correlated with the change in Pcrit (r2= 0.73; P= .003). Increasing CPAP increased both the retroglossal and retropalatal airway dimensions across both masks. After controlling for pressure and breath phase, the retropalatal cross-sectional area was moderately larger when using a nasal vsan oronasal mask (+17.2mm2; 95%CI, 6.2-28.2, P< .001) while nasal breathing. Oronasal masks are associated with a more collapsible airway than nasal masks, which likely contributes to the need for a higher therapeutic pressure.

Is a Difficult Airway Team Needed for Intubation at Removal of Mandibular Distraction Devices for Infants With Robin Sequence?

Difficult airway teams (DATs) are typically present to assist intubation at the initial mandibular distraction osteogenesis (MDO) operation for infants with Robin sequence (RS). In some institutions, the RS diagnosis triggers a "difficult airway" label for the infant, requiring DAT presence for future operations. By the time of distractor removal, however, breathing and airway anatomy are significantly improved. The objective of this study was to measure intubation difficulty and perioperative respiratory complications at MDO device removal as a proxy for the necessity for coordination with a DAT. This is a retrospective study including infants with RS from 2013 to 2021 who had MDO during infancy. Patients were excluded if they had a tracheostomy or MDO device failure. Predictor variables included demographic data, comorbidities, and apnea-hypopnea indices (AHIs) from pre- and immediate post-MDO polysomnograms. The primary outcome measures were number of intubation attempts, laryngoscopy grade, and perioperative respiratory events at the distractor removal operation. Descriptive statistics were computed including Fisher's exact, paired sample t-tests, and Wilcoxon rank tests, and P<.05 was considered statistically significant. The sample included 47 (60% male) patients with a mean age at MDO of 12.0±15.7weeks. Significant improvement in AHI was seen after MDO (pre-MDO: 26.8±18.4 events/hour; post-MDO 2.78±2.66 events/hour; P<.001). Average number of intubation attempts decreased from 2.09±1.36 to 1.30±0.75 (P<.001) and the most common post-MDO laryngoscopy grade was 1 (69%). There were no intraoperative and 2 (4%) minor postoperative respiratory events, both in patients with repaired congenital cardiac disease and not related to traumatic intubation. Neither difficult intubations nor perioperative respiratory events associated with intubation trauma were seen at distractor removal, suggesting that specialty airway assistance is not routinely needed after successful MDO. DAT presence should be determined on a case-by-case basis based on specific patient risk factors.

Diagnostic Performance of Airway Ultrasound for the Assessment of Difficult Laryngoscopy: A Systematic Review and Meta-Analysis

This study aimed to review and appraise the evidence regarding airway ultrasound assessment in predicting difficult laryngoscopy in adult patients. A systematic review of the literature was conducted according to the Cochrane collaboration guidelines and the recommendations for the systematic review and meta-analysis of diagnostic studies. Observational studies that evaluated the diagnostic performance of airway ultrasound for the prediction of difficult laryngoscopy were included for consideration. Literature searches were performed in 4 databases (PubMed [Medline], Embase, Clinical Trials, and Google Scholar) to identify all observational studies using any ultrasound technique to assess difficult laryngoscopy. The search terms included "sonography," "ultrasound," "airway," "difficult airway," "difficult laryngoscopy," "Cormack," "risk factors," "ultrasound at the point of care," "difficult ventilation," "difficult intubation" and others, combined with sensitive filters. The search was done for studies performed in the last 20 years in English or Spanish. Adult patients older than 18 years old under general anesthesia for an elective procedure. Evident anatomic airway abnormalities, obstetric populations, those using an alternative imaging method besides ultrasound, and animal studies were excluded. Preoperative bedside ultrasound measuring distances and ratios from the skin to different reference points, such as the ratio of the hyomental distance in a neutral position (HMDN) and hyomental distance in extension (HMDR), HMDN, and the skin-to-epiglottis distance (SED), the preepiglottic area, and tongue thickness, among others. A total of 24 studies evaluated the prediction of a difficult laryngoscopy using airway ultrasound. The diagnostic performance and the number of ultrasound parameters reported in the studies were variable. Meta-analysis was performed for 3 measurements consistently included in most studies. The SED and the HMDR ratio presented a sensitivity of 75% and 61%, respectively, and a specificity of 86% and 88%, respectively. The ratio of the preepiglottic distance to the epiglottic distance at the midpoint of the vocal cords (pre-E/E-VC) presented the best performance for predicting a difficult laryngoscopy (sensitivity: 82%, specificity: 83%, diagnostic odds ratio: 22.2). With the currently available evidence, the 3 commonly used point-of-care ultrasound measures used to identify difficult laryngoscopy, (SED, HMDR, and pre-E/E-VC), showed better sensitivity and similar specificity to clinical measures. Future studies and more data may change the authors' confidence in these conclusions, given the wide variability of measurements noted in studies.

Penatalaksanaan Anestesi Neonatus yang Menjalani Pembedahan Koreksi Giant Unruptured Occipital Meningoencephalocele

Meningoencephalocele is a rare congenital abnormality where duramater and cranium failed to close completely, leaving part of intracranial tissues outside the cranium wrapped in a sac. Neonate’s airway management, pose many challenges due to immaturity of airway anatomy, limited respiratory organ reserve and extreme head-to-body ratios. Occipital meningoencephalocele will also complicate the intubation and airway control during anesthesia and surgery. A nine days old male patient with an occipital lump measuring 17x12x8 cm underwent meningoencephalocele resection. Induction of anesthesia was performed by sevoflurane inhalation, rocuronium to facilitate videolaryngoscopy and intubation in supine position, supported by doughnut-shape pads which fits the size of the cele. Videolaryngoscope was chosen because it provides optimal visualization without hyperextension and over manipulation than conventional laryngoscope, therefore intubation can be done in supine position. Anesthesia and surgery duration was 2 hours and 15 minutes. The patient was treated in the neonatal intensive care unit after surgery, extubated 24 hours later, and discharged home 10 days after surgery. The greatest challenge in anesthesia management for occipital meningoencephalocele resection is securing the airway while ensuring the sac is not ruptured during airway manipulation and positional changes during anesthesia and surgery.