Incidence Of Difficult Intubation Research Articles

Effectiveness and Validity of Preoperative Ultrasonographic Airway Assessment and Clinical Screening Tests to Predict Difficult Laryngoscopy: A Prospective, Observational Study.

The anticipation of a challenging airway can be demanding in emergency care settings. Due to the patient's clinical condition, executing the pre-intubation clinical screening tests during the management of the airway in an emergency situation can besometimes troublesome. Ultrasonographic airway assessment may become a helpful tool, but no specific sonographic measurements can precisely visualize the prospect of meeting a difficult airway. Therefore, the present study aimed to verdict some correlation between preoperative sonographic airway assessment parameters and the Cormack-Lehane (CL) grading at laryngoscopic view in patients undergoing general anesthesia with endotracheal intubation. Thisobservational study was conducted on 150 elective surgery subjects undergoing general anesthesia. The clinician in the pre-anesthetic clinic performed clinical airway and ultrasonographic airway assessments to predict difficult intubation and correlated with the CL grade viewed at laryngoscopy in the operative room during intubation. The parameters assessed were sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). In this study, the incidence of difficult intubation was 13.3%. The Mallampatti Grading (MPG) showed the maximum receiver operating characteristic (ROC) and area under the curve (AUC) among the clinical predictors, with 86.7% sensitivity. At the same time, the skin-to-hyoid distance has the maximum ROC among the sonographic parameters, and the skin-to-thyroid isthmus has the utmost sensitivity to predict difficult laryngoscopy. Among the clinical predictors, MPG and the sonographic parameters, like the skin-to-hyoid distance and skin-to-thyroid isthmus, are favorable predictors of difficult laryngoscopy.

Problems of endotracheal intubation in obese patient

Background: Performing intubation in obese patients is a challenging problem both in the intensive care unit (ICU) and patients with a high BMI face various complication.
 Methods: A prospective multiplex cohort study in Kirkuk governorate was conducted in obese patients (body mass index greater than 30 kg m2). The primary endpoint was the occurrence of difficulty intubation. Secondary endpoints were risk factors for difficult intubation, use of difficult airway management techniques, and serious, life-threatening complications related to intubation (cardiac problems, hypoxaemia, and severe cardiovascular collapse). 
 Results: Out of 100 patients, 48 patients had problems and complications as a result of intubation. These complications varied from simple to serious. 7 patients experienced hypoxia, 22 patients experienced difficulty in intubation, 5 patients experienced cardiac arrhythmias, and 2 patients had a dental injury that was. This complication is related to the body mass index. 
 Conclusions: In severely obese patients, the incidence of difficult intubation in the intensive care unit was related to BMI. Researchers did not encounter deaths resulting from intubation, perhaps due to the development of medicine and new tools.

Pre-epiglottic Space and Epiglottis to Vocal Cord Ratio in Order to Predict Difficult Intubation in Adults: A Multivariate Analysis

Objective: We aimed to enhance the prediction of difficult intubation by using ultrasonographic parameters (pre-epiglottic space (Pre-E), distance between epiglottis to middle part of vocal cord (E-VC) and Pre-E/E-VC) adjusting for traditional airway assessments. Material and Methods: This prospective cohort study was conducted at a super-tertiary care hospital in Thailand. Participants aged 18-65 years with ASA classification I-III and who required general anesthesia with endotracheal intubation were included. Preoperative traditional and ultrasonographic airway assessments were performed by two investigators. The outcome was difficult intubations as diagnosed by laryngoscopic view grade 3 or 4. Multivariate logistic regression was used to identify predictors for difficult intubation presented by adjusted odds ratio (OR) and 95% confidence interval (CI). Results: A total of 94 patients were recruited. The incidence of difficult intubation was 15%. The median Pre-E/E-VC ratio among this group was 0.8 compared with 1.0 in the control group (p-value 0.124). The cut-off point of <1.0 of Pre- E/E-VC was not associated with difficult intubation after adjusting for sex and other traditional parameters (p-value 0.11). Predictors of difficult intubation were female sex (OR [95% CI]: 13.8 [2.8, 68.3]), sternomental distance ≤175 mm (OR [95% CI]: 11.6 [1.9, 71.4]) and interincisor gap <4 cm (OR [95% CI]: 19.8 [1.1, 373.8]) with the area under the receiver operating characteristic curve at 0.88 and a specificity of 90.0%. Conclusion: There was no association between the Pre-E/E-VC in predicting difficult intubation in low-risk patients. The ultrasonographic measurements of Pre-E/E-VC were not helpful in predicting difficult intubations in our setting. Trial registration: thaiclinicaltrials.org: TCTR20180115002, Registered 9 January 2018 - Prospectively registered, https:// www.thaiclinicaltrials.org/#

Airway assessment: Predictors for difficult intubation – A prospective observational study

Airway management remains an important challenge in the contemporary practice of anaesthesia and preoperative airway assessment facilitates appropriate preparation when difficulty with intubation or ventilation is anticipated prior to induction of anaesthesia.: Aim: To study the important predictors for difficult laryngeal intubation. To determine the predictors of difficult laryngeal intubation. Secondary: To determine the most significant predictor for difficult intubation and to determine the incidence of unanticipated difficult intubation.This single centre prospective observational study done in Bangalore Baptist hospital (after obtaining clearance from ethical committee) included adult patients posted for elective surgeries who received general anaesthesia. Patients of either gender in the 18 – 65 year age group, with an American Society of Anaesthesiologists physical status classification of I or II, who required endotracheal intubation for general anaesthesia. The sample size was 413 with confidence level 95%. In our study the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of Mallampati class were found to be 75.8%, 78.06%, 37.90%, 94.80% respectively. The sensitivity, specificity, PPV and NPV of mouth opening were found to be 33.87%, 81.19%, 24.13%, 87.42% respectively. The sensitivity, specificity, PPV and NPV of upper lip bite test found to be 27.41%, 96.29%, 56.66%, 88.25% respectively. The sensitivity, specificity, PPV and NPV of neck extension found to be 54.83%, 92.59%, 56.66%, 92.06% respectively. The sensitivity, specificity, PPV and NPV of BMI found to be 53.22%, 75.49%, 27.73%, 90.13% respectively. The incidence of difficult intubation was 15%.:In conclusion, no single predictor is sufficient for prediction of difficult intubation on its own. All the studied bedside tests are poor to moderate predictors of difficult intubation. All the tests showed poor positive predictive values and high negative predictive values which suggests that they can be more useful predictors of easy intubation than difficult intubation.

Perioperative Hypoxemia and Postoperative Respiratory Events in Infants with Hypertrophic Pyloric Stenosis.

Normalization of metabolic alkalosis is an important pillar in the treatment of infantile hypertrophic pyloric stenosis (IHPS) because uncorrected metabolic alkalosis may lead to perioperative respiratory events. However, the evidence on the incidence of respiratory events is limited. We aimed to study the incidence of peroperative hypoxemia and postoperative respiratory events in infants undergoing pyloromyotomy and the potential role of metabolic alkalosis. We retrospectively reviewed all patients undergoing pyloromyotomy between 2007 and 2017. All infants received intravenous fluids preoperatively to correct metabolic abnormalities close to normal. We assessed the incidence of perioperative hypoxemia (defined as oxygen saturation [SpO2] < 90% for > 1min) and postoperative respiratory events. Additionally, the incidence of difficult intubations was evaluated. We performed a multivariate logistic regression analysis to evaluate the association between admission or preoperative serum pH values, bicarbonate or chloride, and peri- and postoperative hypoxemia or respiratory events. Of 406 included infants, 208 (51%) developed 1 or more episodes of hypoxemia during the perioperative period, of whom 130 (32%) experienced it during induction, 43 (11%) intraoperatively, and 112 (28%) during emergence. About 7.5% of the infants had a difficult intubation and 17 required more than 3 attempts by a pediatric anesthesiologist. Three patients developed respiratory insufficiency and 95 postoperative respiratory events were noticed. We did not find a clinically meaningful association between laboratory values reflecting metabolic alkalosis and respiratory events. IHPS frequently leads to peri- and postoperative hypoxemia or respiratory events and high incidence of difficult tracheal intubations. Preoperative pH, bicarbonate, and chloride were bad predictors of respiratory events.

Prediction of Difficult Endotracheal Intubation by Different Bedside Tests

Background: An incidence of difficult intubation in elective surgery is 1.5%–8%. Multiple attempts during tracheal intubation can cause airway injuries bleeding, brain hypoxia, and even cardiac arrest. Unanticipated failure and inability to secure difficult airway can lead to “cannot ventilate, cannot intubate” condition. Preoperative assessment and bedside tests play a vital role in predicting and stratifying risk of difficult intubation. This study was done to determine the incidence of difficult intubation and diagnostic accuracy of different bedside tests for predicting intubation difficulty in patients without airway pathology scheduled for elective surgery under general anesthesia. Materials and Methods: Two hundred patients, aged 20–50 years, American Society of Anaesthesiologists I and II, without airway pathology undergoing elective surgery were evaluated preoperatively using simple bedside tests such as Mallampati grading (MPG), interincisor gap (IIG), thyromental distance (TMD), sternomental distance, upper lip bite test, neck circumference, and atlantooccipital extension to predict difficult intubation. Statistical confirmation was done using Pearson’s chi-square test and univariate and multivariate logistic regression. Results: In our study, the incidence of difficult intubation was observed as 6%. High sensitivity for predicting difficult intubation was seen with IIG &gt; TMD &gt; MPG, and high specificity among the relevant bedside tests was seen with TMD &gt; MPG &gt; IIG. Tests with high positive predictive value were TMD &gt; MPG, whereas high negative predictive value was seen with IIG &gt; TMD &gt;MPG. Conclusion: IIG, TMD, and MPG can be used to predict difficult intubation in patients without airway pathology.

Predictive Machine Learning Algorithms in Anticipating Problems with Airway Management

Machine learning is artificial intelligence (AI) which can predict the output variable with the fed input features. This allows computers to learn from experience without being programmed. The outcome variable in machine learning algorithm may be continuous variable or categorical variable. Supervised machine learning is commonly applied artificial intelligence (AI) in medical field. Decision tree, gradient boost machine (GBM) learning, extreme GBM (XGBM), Support vector machine, K nearest neighbour and multi-layer perceptron are few machine learning algorithms which are being utilised to address the classification and regression problems. Though the incidence of difficult intubation (DI) is rare, occurrence of such event in an unanticipated situation can result in development of arrhythmias due to desaturation and cardiac arrest if not intervened on time. It is preferred to choose the physical parameters that can predict the difficult airway more accurately in clinical scenario and train the algorithm rather than including all the non-specific parameters. Body mass index (BMI) [&gt;30 kg.m-2: anticipated difficult mask ventilation (DMV), direct laryngoscopy (DL) and DI], inter-insicor distance (IID) (&lt;2 cm: anticipated DL), modified Mallampati (MMP) (Grade 1 and 2: Ease of intubation; Grade 3 and 4: anticipated DI), temporomandibular distance (TMD) (&lt;6.5 cm - anticipated DI), restriction of neck extension (if present: anticipated DL and DI), receded mandible (if present: anticipated DL and DI), and poor submandibular space compliance (if present: anticipated DL and DI) parameters which are used to predict DA by clinical assessment, can be used to feed to train the machine learning algorithm. Despite using these sophisticated tools, extubation may fail and patients require reintubation in ICU. It is very challenging to assess the lung compliance in spontaneously breathing patients as compliance will be overestimated due to generation of negative pressure. Cause for which patient has been placed on mechanical ventilation is resolved/resolving, BMI (&gt;30 kg.m-2), intact sensorium (absence of delirium), absence of consolidation, absence of copious secretions, oxygenation status (PaO2/FiO2: &gt;250), ventilation status (paCO2: 30-45 mmHg), measure of work of breathing (respiratory rate, rapid shallow breathing index), heart rate and blood pressure during spontaneous breathing trial (SBT) and diaphragmatic thickness fraction can be used as input features to predict the success of extubation in critically ill patients. With widespread utility of applications in medical fraternity, applications for prediction of difficult airway (or for weaning success) can be programmed which can be accessed by the clinicians to predict DA, thereby all the preparations for managing DA may be done to prevent adverse consequences of unanticipated difficult airway.

Pharynx volume derived from three-dimensional computed tomography is associated with difficult intubation in spinal deformity surgery: A retrospective cohort study.

Spinal abnormality surgery, including surgery for ankylosing spondylitis and idiopathic scoliosis, can present significant challenges to anesthesiologists because of the potential difficult airway. The bedside screening tests routinely used to detect difficult airways are highly variable. Pharynx volume calculated using three-dimensional (3D) computed tomography (CT) may play a role in predicting difficult airways.We conducted a retrospective cohort study on patients (aged ≥14 years) who received orthopedic surgery for ankylosing spondylitis/idiopathic scoliosis under general anesthesia. Volume of the pharynx air space was calculated through volume rendering technique by 3D reconstruction of patients’ cervical spine CT. Patients were divided into 2 groups according to their pharynx volume, pharyngeal volume lower than 16 mL (n = 11) and equal or higher than 16 mL (n = 13).Pharynx volume in low volume group was 10.4 ± 3.6 mL (n = 11), and the counterpart in high volume group was 20.8 ± 5.5 mL (n = 13). The incidence of difficult intubation was significantly higher in low pharynx volume group than in high pharynx volume group (54.5% (6/11) vs 7.6% (1/13), P = .023). Bedside screening tests including modified Mallampati test, inter-incisor gap and thyromental distance, or radiological variables such as anterior neck soft tissue thickness to vocal cords were not different between the 2 groups.Smaller pharynx volume played an important role in difficult airways for patients undergoing orthopedic surgery for ankylosing spondylitis/idiopathic scoliosis.

The Anesthetic Strategy for Patients with Mucopolysaccharidoses: A Retrospective Cohort Study.

Anesthesia for patients with mucopolysaccharidoses (MPS) is quite challenging due to vital systemic dysfunction following progressive accumulation of lysosomal glycosaminoglycans. Previous studies focused on perioperative difficult airway management under general anesthesia but rarely depicted the concern of choosing the size of the endotracheal tube (ETT) as well as neuraxial anesthesia. This study aimed to analyze the overall anesthetic management and related complications for a thorough anesthetic strategy. Within the study period from 2002 to 2021, each record of the anesthetic and perioperative quality assurance/improvement system for patients with a diagnosis of MPS at MacKay Memorial Hospital was retrospectively reviewed. A total of 51 individuals with 151 anesthesia for 163 interventions were cohort studied, and there were 136 general anesthesia and 15 neuraxial anesthesia. We found that the most common interventions for MPS patients were otolaryngological surgeries (49.6%). Additionally, a secured airway played a marked preference for the most general anesthesia (87.1%). The incidence of difficult intubation was 12.5%. In view of ETT size, a smaller than estimated size was used in MPS type II, III, IV, and VI patients and also in patients who received intubation with multiple attempts. However, a larger than estimated size of ETT was adopted whilst choosing cuffed ones. For neuraxial anesthesia, two failed spinal anesthesia procedures were converted to general anesthesia and 73 percent of the patients received perioperative sedation. In conclusion, through the individualized anesthetic strategy and build-up of an experienced team for airway management, high-quality anesthesia can be ensured in each patient.

Incidence of difficult airway among adult patients of undiagnosed obstructive sleep apnea who are undergoing elective surgery: a prospective cohort study

Introduction: Obstructive sleep apnea (OSA) is a dangerous medical disorder marked by obstruction of the upper airway during sleep that is frequently undiagnosed before surgery. Preoperative identification of suspected OSA patients necessitates appropriate preparation and prevents unfavorable outcomes. The incidence of difficult airway in adult patients with OSA who are undergoing elective surgery is significantly increased. Materials and method: The study population was separated into high and low-risk groups based on STOP-BANG scores of ≥3 and &lt;3, respectively. The rate of occurrence was compared between the study groups. SPSS version 23 was used for statistical analysis. P-values &lt;0.05 are considered significant. To find characteristics that predict problematic airway, researchers used logistic regression. Result: A total of 113 participants was enrolled. Based on STOP-BANG 77 patients and 36 patients were grouped in to low risk OSA and high risk OSA, respectively, the incidence of difficult intubation (DI) was significantly higher (22.2%) in high risk OSA group versus 5.2% in low risk OSA group, relative risk of 4.278 (95% confidence interval: 1.378–13.2). Mask ventilation was significantly more problematic for the high-risk group (P=0.011) (25% against 6.5%). Male sex, neck circumference &gt;40 cm, Mallampati class 3, and 12.5 cm stern mental distance were all linked to DI. Age above 50 years, snoring history, and a neck circumference of &gt;40 cm were all found to be predictors. Conclusion: Patients who scored ≥3 on the STOP-BANG had a significantly higher rate of DI and difficult mask ventilation. As a result, the STOP-BANG questionnaire should be used to screen every adult patient undergoing elective surgery for OSA.

A Prospective Study to Correlate Difficult Intubation with Difficult Laryngeal Exposure for Microlaryngeal Surgery using Various Grading Scales of Difficult Intubation.

Adequate visualization of the vocal folds is essential for optimal phonosurgery. Pre-operative knowledge of a difficult laryngeal exposure (DLE) can alert the surgeon regarding the need for alternative measures. Our study is based on the hypothesis that a patient who has difficult intubation (DI) is likely to have DLE, thus scales anticipating DI should also anticipate DLE. Our aims were to correlate patients of actual DI on table with patients who had DLE, secondly to assess the ability of grading scales of DI to predict DLE and finally to obtain a cut-off value of neck circumference and length for predicting DLE. This is a prospective, observational study wherein four grading scales; Modified Mallampati Classification (MMC), 3-3-2, Upper lip bite test (ULBT) and Neck Mobility (NM) were used for anticipating DI and correlated with DLE during MLS. Occurrence of actual DI and DLE was correlated. Neck circumference and neck length was correlated with incidence of DLE. Out of 42 patients, 22 were anticipated to have DI (52.38%). Actual incidence of DI was 6 (14.28%) and DLE was 10 (23.80%). Correlation between actual DI and DLE was statistically significant. Of the 4 grading scales, ULBT was significant in predicting DLE. Neck circumference more than 37.5cm and neck length less than 15.3cm was significant in anticipating DLE. There is a significant correlation between DI and DLE. A positive ULBT, neck circumference more than 37.5 cms and neck length less than 15.3 cms are independently suggestive of a DLE.

Predicting difficult laryngoscopy in morbidly obese Thai patients by ultrasound measurement of distance from skin to epiglottis: a prospective observational study

BackgroundIn morbidly obese patients, airway management is challenging since the incidence of difficult intubation is three times than those with a BMI within the healthy range. Standard preoperative airway evaluation may help to predict difficult laryngoscopy. Recent studies have used ultrasonography-measured distance from skin to epiglottis and pretracheal soft tissue at the level of vocal cords, and cut-off points of 27.5 mm and 28 mm respectively have been proposed to predict difficult laryngoscopy. The purpose of this study is to evaluate ultrasonography-measured distance from skin to epiglottis for predicting difficult laryngoscopy in morbidly obese Thai patients.MethodsThis prospective observational study was approved by the Ethics Committee of the Faculty of Medicine, Prince of Songkla University. Data were collected from January 2018 to August 2020. Eighty-eight morbidly obese patients (BMI ≥ 35 kg/m2) requiring general anesthesia with endotracheal intubation for elective surgery were enrolled in the Songklanagarind Hospital. Preoperatively, anesthesiologists or nurse anesthetists who were not involved with intubation evaluated and recorded measurements (body mass index, neck circumference, inter incisor distance, sternomental distance, thyromental distance, modified Mallampati scoring, upper lip bite test, and distance from skin to epiglottis by ultrasound. The laryngoscopic view was graded on the Cormack and Lehane scale.ResultsMean BMI of the eighty-eight patients was 45.3 ± 7.6 kg/m2. The incidence of difficult laryngoscopy was 14.8%. Univariate analysis for difficult laryngoscopy indicated differences in thyromental distance, sternomental distance and the distance from skin to epiglottis by ultrasonography. The median (IQR) of thyromental distance in difficult laryngoscopy was 6.5 (6.3, 8.0) cm compared with 7.5(7.0, 8.0) cm in easy laryngoscopy (p-value 0.03). The median (IQR) of sternomental distance in difficult laryngoscopy was 16.8 (15.2, 18.0) cm compared with 16.0 (14.5, 16.0) cm in easy laryngoscopy (p-value 0.05). The mean distance from skin to epiglottis was 12.2 ± 3.3 mm Mean of distance from skin to epiglottis in difficult laryngoscopy was 12.5 ± 3.3 mm compared with 10.6 ± 2.9 mm in easy laryngoscopy (p-value 0.05). Multivariate logistic regression indicated the following factors associated with difficult laryngoscopy: age more than 43 years (A), thyromental distance more than 68 mm(B) and the distance from skin to epiglottis more than 13 mm(C). The scores to predict difficult laryngoscopy was calculated as 8A + 7B + 6C based on the data from our study. One point is given for A if age was more than 43 years old, 1 point is given for B if thyromental distance was less than 6.8 cm and 1 point is given for C if the distance from skin to epiglottis by ultrasonography was more than 13.0 cm. The maximum predicting score is 21, which indicates a probability of difficult laryngoscopy among our patients of 36.36%, odds 0.57, likelihood ratio 3.29 and area under the ROC curve of 0.77, indicative of a good predictive score.ConclusionsAge, thyromental distance and ultrasonography for the distance from skin to epiglottis can predict difficult laryngoscopy among obese Thai patients. The predictive score indicates the probability of difficult laryngoscopy.

Abstract No. : ABS1378: Correlation between upper airway ultrasound and Cormack- Lehane grading during laryngoscopy-A prospective study

Background & Aims:Difficult and failed tracheal intubation after direct laryngoscopy is a dreaded complication of general anaesthesia. Preoperative prediction of the Cormack-Lehane (CL) grade with ultrasonographic measurements of ANS-Hyoid, ANS-VC, PES&EVL can help in better airway management during general anaesthesia.Methods:We studied 100 patients undergoing elective surgery under general anaesthesia. Study was carried out in two phases. Firstly, during preanaesthetic checkup, Mallam pati grade (MPG), Sternomental distance (SMD), Thyromental distance (TMD) and ultrasound measurements of the anterior neck soft tissue thickness at the level of the hyoid (ANS-Hyoid), at the level of the vocal cords (ANS-VC) and ratio of the depth of the pre-epiglottic space (Pre-E) to the distance from the epiglottis to the mid-point between the vocal cords (E-VC) were obtained, CL grade was noted during laryngoscopy. Chi-square test wasapplied to predict any statistically correlation between measurement of ultrasonographic parameters and CL grade.Results:The incidence of difficult intubation was 15%. An ANS-VC>0.32 had sensitivity of 100% in predicting a CL grade of 3 and4, which was higher than ANS-hyoid, PES/EVL, MPG, SMD, TMD, while specificity and PPV were lower. Conclusion:Ultrasound is a useful test in airway assessment. ANS-VC>0.32 is a potential predictor of difficult intubation. ANS-hyoid, PES/EVL are not indicative of difficult intubation.

Conceptualization of Artificial Intelligence in Airway Management

Background: Failed intubation is the single most important cause of patient morbidity and mortality during anesthesia for surgery. The incidence of difficult intubation could be as high as 12% while failed intubation is around 0.5%.1 Disaster and mass casualty management may increase this risk multi-fold due to the paucity of airway-trained medical personnel.2 Automation of the entire procedure could potentially save lives particularly in situations where mass casualties could happen without the immediate availability of skilled airway specialists. Thanks to the combination of existing technology involving 3-D image capture, artificial intelligence (AI), machine learning (ML) for image analysis, and robotics, airway management could be revolutionized. Work is already underway in this domain, but many challenges still need to be overcome to make the technology more practical and user-friendly.3Methods: Experts in the above fields from Hamad Medical Corporation (Qatar), Qatar University (Qatar), and Teesside University (UK) were brought together to collaborate on this potentially game-changing technological solution. The team includes clinicians specialized in airway management, engineers with a very strong track record of accomplishments in artificial intelligence and computer algorithm-based software development. The team is regularly meeting online to discuss the integration of the various technologies to develop a prototype automated device. Recommendations: A concept model based on Clinical-Technology-Research integration was arrived at as illustrated in Figure 1. The team is presently seeking funding to start the development of a working prototype combining AI, ML, and robotics. The planned work packages are briefly presented in Table 1. Conclusion: This work has shown that an automated device to disrupt the practice in airway management is feasible and could save lives particularly in disaster management and in geographical areas with a lack of clinicians with expertise in airway management.

Comparison of Upper Lip Bite Test with Modified Mallampati Score in Predicting Difficult Intubation

Background and Aims: Identifying a patient with a difficult airway is important in planning anaesthetic management so that endotracheal intubation can be achieved safely. This study aims to compare modified Mallampati score with Upper Lip Bite Test to predict difficult intubation using intubation difficulty scale. Materials and methods: A prospective study was carried on 104 patients, both sexes aged between 18 to 60 years scheduled for elective surgeries under general anaesthesia fulfilling inclusion and exclusion criteria. Patient airway was evaluated by MMT and ULBT preoperatively. Predictors of difficult endotracheal intubation were assigned to MMT class III and IV, ULBT class III. After premedication and induction laryngoscopy was performed. After successful intubation Intubation difficulty score was noted down based on the sum of seven assessing parameters. A score &gt;5 was considered difficult intubation. Results: The incidence of difficult intubation in the study was 10.6% (i.e. 11 out of 104 patients). In this study ULBT had a higher sensitivity (90.9% v/s 18.20%), specificity (95.7% v/s 75.3%) PPV (71.4% v/s 8%) and NPV (98.9% v/s 88.6%) than that of MMT Conclusion: Upper lip bite test is better at predicting difficult intubation with higher accuracy when compared to Modified Mallampati test. Both the tests are good predictors of easy intubation. Keywords: Upper Lip Bite Test (ULBT), Modified Mallampati test (MMT), Intubation Difficulty scale (IDS), airway assessment. Difficult intubation prediction, Difficult airway

Evaluation of thyromental height as a predictor of difficult laryngoscopy and difficult intubation: a cross-sectional observational study

Background and objectivesSeveral anthropometric measurements have been suggested to identify a potentially difficult airway. We studied thyromental height (TMH) as a predictor of difficult laryngoscopy and difficult intubation. We also compared TMH, ratio of height to thyromental distance (RHTMD), and thyromental distance (TMD) as predictors of difficult airway. MethodsThis cross-sectional observational study was conducted in 300 adult surgical patients requiring tracheal intubation. Preoperatively airway characteristics were assessed. Standard anesthesia was administered. Degree of difficulty with mask ventilation, laryngoscopic view, duration of laryngoscopy, and difficulty in tracheal intubation (intubation difficulty scale score) were noted. Multivariate logistics regression analysis was performed to identify independent predictors for difficult laryngoscopy. ResultsLaryngoscopy was difficult in 46 of 300 (15.3%) patients; all 46 patients had Cormack-Lehane grade 3 view. Duration of laryngoscopy was 27........11...s in patients with difficult laryngoscopy and 12.7........3.9...s in easy laryngoscopy; p...=...0.001. Multivariate analysis identified that TMH, presence of short neck, and history of snoring were independently associated with difficult laryngoscopy. Incidence of difficult intubation was 17.0%. A shorter TMH was associated with higher IDS scores; r...=...-0.16, p...=...0.001. TMH and duration of laryngoscopy were found to be negatively correlated; a shorter TMH was associated with a longer duration of laryngoscopy; r...=...-0.13, p...=...0.03. The cut-off threshold value for TMH in our study is 4.4 cm with a sensitivity of 66% and a specificity of 54%. ConclusionThyromental height predicts difficult laryngoscopy and difficult intubation.TMD and RHTMD did not prove to be useful as predictors of difficult airway.

COMPARISON OF UPPER LIP BITE TEST AND MODIFIED MALLAMPATI TEST FOR PREDICTION OF DIFFICULT INTUBATION

Background: Insertion of endotracheal tube is the basic skill acquired by all anesthesiolo­gists. An unanticipated difficult intubation can be catastrophic and is one of the major causes of morbidity and mortality in anesthetic practice. So, there are multiple screening tests de­signed to correctly predict difficult intubation but none of them are 100 % accurate. The study aimed to compare the Modified Mallampatti test with Upper Lip Bite test for correct prediction of difficult intubation. Methods: A cross-sectional study was conducted in the College of Medical Sciences, Bharatpur from 16th June 2020 to December 31st 2020. A total of 610 patients requiring general anesthe­sia with endotracheal intubation were included in the study. The Modified Mallampatti test and Upper Lip Bite test along with laryngoscopy was performed by an experienced anesthesiologist. Sensitivity, specificity, accuracy and positive and negative predictive values for both tests were calculated and compared. Results: The incidence of difficult intubation was 17.7% in our study. The upper lip bite test showed better sensitivity (79.63% vs 37.96%), specificity (93.82% vs 69.92%), positive predictive value (73.5% vs 21.35%), negative predictive value (95.53% vs 83.97%) and accuracy (91.31% vs 64.26%) compared to Modified Mallampatti test Conclusions: Upper lip bite test was a better predictor of difficult intubation compared to MMT with higher accuracy and predictive values.

P.47 Airway assessment on the labour ward

Introduction: The incidence of difficult intubation in the obstetric population is 1 in 250. [1] McDonnell NJ, Paech MJ, Clavsi OM, et al, the ANZCA Trails Group. Difficult and failed intubation in obstetric anaesthesia: an observational study of airway management and complications associated with general anaesthesia for caesarean section. Int J Obstet Aneth 2008;17:292-7. Google Scholar With the infrequent use of general anaesthesia, the anaesthetist must be prepared for potential difficulty. [2] Searle RD, Lyons G. Vanishing experience in training for obstetric general anaesthesia: an observational study. Int J Obstet Anesth 2008;17:233-7. Google Scholar This includes performing a detailed airway assessment prior to administering labour analgesia or anaesthesia. Previous departmental data found that 70% of patients undergo a comprehensive airway assessment. Recently the anaesthetic chart was modified to specifically indicate the presence or absence of a potentially difficult airway. We aimed to re-audit how comprehensive the initial airway assessment was, and whether potentially difficult airways were being highlighted.

Ratios of Height-to-Thyromental Distance and Height-to-Sternomental Distance as Predictors of Difficult Airway in Patients Posted for General Anaesthesia.

Preoperative airway assessment and anticipation of a difficult airway is of utmost critical value in anesthesiology as failure to secure airway can lead to morbidity and mortality. The study evaluated ratio of height-to-thyromental distance (RHTMD) and ratio of height-to-sternomental distance (RHSMD) as predictors of a difficult airway. The prospective observational study evaluated 131 adult participants scheduled for elective surgery under general anesthesia. In addition to the preoperative airway assessment, RHTMD and RHSMD were calculated. Correlation of these ratios with the Cormack-Lehane grading of glottis visualisation on direct laryngoscopic view following induction of anesthesia was analyzed. The optimal cut-off point for RHTMD and RHSMD were identified using receiver operating characteristic curve analysis. The incidence of difficult intubation was 14.50%. The cut-off values for RHTMD and RHSMD were ＜ 21.50 (sensitivity 85.25%, specificity 100.00%) and ＜ 10.50 (sensitivity 84.21%, specificity 96.42%) respectively for predicting difficult airway. The area under the curve with 95% confidence interval for RHTMD was 0.875 (0.730-1.000) and that for RHSMD was 0.890 (0.777-1.000). RHTMD was found to be a better predictor of difficult intubation and restricted laryngoscopic view compared to RHSMD.

Difficult tracheal intubation in neonates and infants. NEonate and Children audiT of Anaesthesia pRactice IN Europe (NECTARINE): a prospective European multicentre observational study

BackgroundNeonates and infants are susceptible to hypoxaemia in the perioperative period. The aim of this study was to analyse interventions related to anaesthesia tracheal intubations in this European cohort and identify their clinical consequences. MethodsWe performed a secondary analysis of tracheal intubations of the European multicentre observational trial (NEonate and Children audiT of Anaesthesia pRactice IN Europe [NECTARINE]) in neonates and small infants with difficult tracheal intubation. The primary endpoint was the incidence of difficult intubation and the related complications. The secondary endpoints were the risk factors for severe hypoxaemia attributed to difficult airway management, and 30 and 90 day outcomes. ResultsTracheal intubation was planned in 4683 procedures. Difficult tracheal intubation, defined as two failed attempts of direct laryngoscopy, occurred in 266 children (271 procedures) with an incidence (95% confidence interval [CI]) of 5.8% (95% CI, 5.1–6.5). Bradycardia occurred in 8% of the cases with difficult intubation, whereas a significant decrease in oxygen saturation (SpO2<90% for 60 s) was reported in 40%. No associated risk factors could be identified among co-morbidities, surgical, or anaesthesia management. Using propensity scoring to adjust for confounders, difficult anaesthesia tracheal intubation did not lead to an increase in 30 and 90 day morbidity or mortality. ConclusionsThe results of the present study demonstrate a high incidence of difficult tracheal intubation in children less than 60 weeks post-conceptual age commonly resulting in severe hypoxaemia. Reassuringly, the morbidity and mortality at 30 and 90 days was not increased by the occurrence of a difficult intubation event. Clinical trial registrationNCT02350348.