Incidence Of Difficult Laryngoscopy Research Articles

Impact of Universal Use of the McGrath Videolaryngoscope as a Device for All Intubations in the Cardiac Operating Room. A Prospective Before-After VIDEOLAR-CAR Study

Tracheal intubation in cardiac surgery patients has a higher incidence of difficult laryngoscopic views compared with patients undergoing other types of surgery. The authors hypothesized that using the McGrath Mac videolaryngoscope as the first intubation option for cardiac surgery patients improves the percentage of patients with "easy intubation" compared with using a direct Macintosh laryngoscope. A prospective, observational, before-after study. At a tertiary-care hospital. One thousand one hundred nine patients undergoing cardiac surgery. Consecutive patients undergoing cardiac surgery were intubated using, as the first option, a Macintosh laryngoscope (preinterventional phase) or a McGrath Mac videolaryngoscope (interventional phase). The main objective was to assess whether the use of the McGrath videolaryngoscope, as the first intubation option, improves the percentage of patients with "easy intubation," defined as successful intubation on the first attempt, modified Cormack-Lehane grades of I or IIa, and the absence of the need for adjuvant airway devices. A total of 1,109 patients were included, 801 in the noninterventional phase and 308 in the interventional phase. The incidence of "easy intubation" was 93% in the interventional phase versus 78% in the noninterventional phase (p < 0.001). First-success-rate intubation was higher in the interventional phase (304/308; 98.7%) compared with the noninterventional phase (754/801, 94.1%; p = 0.005). Intubation in the interventional phase showed decreases in the incidence of difficult laryngoscopy (12/308 [3.9%] v 157/801 [19.6%]; p < 0.001), as well as moderate or difficult intubation (5/308 [1.6%] v 57/801 [7.1%]; p < 0.001). The use of the McGrath videolaryngoscope as the first intubation option for tracheal intubation in cardiac surgery improves the percentage of patients with "easy" intubation," increasing glottic view and first-success-rate intubation and decreasing the incidence of moderate or difficult intubation.

Topical Anaesthesia Using a Soft Mist Spray Device Allows Comfortable Awake Visualisation of the Airway via Self-Videolaryngoscopy in Volunteers.

Background: During endotracheal intubation, there is a 10% incidence of difficult laryngoscopy, which may result in serious complications. It is important to obtain as much information about the visibility of laryngeal structures before the patient is anaesthetised. Performing awake (video-) laryngoscopy on a patient is uncomfortable and can trigger gagging and coughing reflexes, making visualisation nearly impossible. The objective of this study is to evaluate the effectiveness of a soft mist spray device for airway anaesthesia during awake (video-) laryngoscopy. Methods: Twenty healthy volunteers inhaled through the Trachospray device, which was placed in their mouths. Two 2 mL syringes containing lidocaine at 4% were sprayed into the airway during inspiration. After several minutes, the subjects were asked to perform a videolaryngoscopy on themselves until the glottic structures and the vocal cords were visible. Upon completion of the procedure, all participants were asked to fill out a feedback form. Results: The duration of the videolaryngoscopy to visualisation of the vocal cords averaged 17 ± 13 s. After analysing the data, three distinct groups emerged as follows: Group 1 (70% of participants) showed no response, allowing for easy insertion of the videolaryngoscope. Group 2 (25% of participants) exhibited a light response but still permitted easy insertion and visualisation. One patient demonstrated a clear response with noticeable laryngeal contraction, requiring slightly more effort and discomfort for insertion. In 80% of the participants, the laryngeal structures were visualised according to Cormack-Lehane grade 1. All participants reported a high level of comfort, with an average rating of NRS 8. The anaesthesiologist assessed the level of anaesthesia as good to very good. No adverse events were observed. Conclusions: The Trachospray provided good, reliable, comfortable, and safe topical anaesthesia for awake videolaryngoscopy. This enables a direct visual assessment of the airway and may assist in making decisions regarding airway management for tracheal intubation.

Evaluation of Thyromental Height Test for Predicting Difficult Laryngoscopy in Morbid Obese Patients Candidate for Bariatric Surgery: An Observational Study

Upper airway management in morbid obese patients undergoing bariatric surgery is a major challenge during induction of anesthesia. Bed side Thyromental Height Test (TMHT) is an easy and valid predictor for prediction of difficult airway in non‑obese patients, but its precision in morbid obese patients haven’t been evaluated yet. The purpose of present study is to find the accuracy of TMHT for the prediction of difficult laryngoscopy in morbid obese patients undergoing bariatric surgery. The present prospective observational study was performed on 95 morbid obese patients at Sina hospital during 2020. Preoperative exams of patients include the assessment of Mallampati classification, thyromental height, thyromental, sternomental and interincisor distances. After induction of anesthesia, the laryngoscopy view was evaluated using the Cormack Lehane classification, and the relationship between these tests to prediction of difficult laryngoscopy view based on the Cormack Lehane degrees (grades 3,4) were evaluated. A total of 95 morbid obese patients with a mean BMI of 44.7±5.6 kg/m2.were included in the study. 67.3% of them were women. The incidence of difficult laryngoscopy (C &amp; L III, IV) was 16.8%. TMHT less than 56.5 mm, with 98% positive predictive value and 93% accuracy was the best predictor of difficult intubation in these patients. The accuracy of thyromental, sternomental and interincisor distance, with cut off value less than 51.5 mm, 89.5 mm, 41.5 mm respectively was less than TMHT in prediction of difficult laryngoscopy in morbid obese patients. In morbid obese patients with a BMI greater than 40, thyromental height less than 56.5 mm with 98% positive predictive value and 93% accuracy is the best predictor for difficult laryngoscopy view.

Preoperative ultrasonographic evaluation of the airway vis-à-vis the bedside airway assessment to predict potentially difficult airway on direct laryngoscopy in adult patients—a prospective, observational study

BackgroundUnanticipated difficult airway remains a challenge for the anesthesiologist with no established standard criteria to predict difficulty in intubation. Our aim was to correlate the pre-anesthetic ultrasonographic (USG) airway assessment parameters with Cormack-Lehane (CL) grade at direct laryngoscopy view under general anaesthesia.This was a prospective, observational study on 150 adult patients between 18 and 70 years with the American Society of Anesthesiologist—Physical Status 1–2 requiring general endotracheal anesthesia for elective surgery.ResultsThe incidence of difficult laryngoscopy was 22.7%. The sonographic distance from anterior neck surface to epiglottis (ANS-E) > 1.67 cm was observed to be a statistically significant USG predictor of difficult laryngoscopic view with sensitivity of 64.71% and specificity of 78.45% (p = 0.000). The sonographic distance from anterior neck surface to hyoid bone (ANS-H) or to anterior commissure (ANS-AC) did not corelate with difficult laryngoscopy. The ultrasound (US) parameters had higher negative than positive predictive value.ConclusionsWe found ANS-E distance to be the most significant predictor of difficult laryngoscopy in our study. USG is a useful tool to identify the “at-risk” patients for difficult airway.

Evaluation of neck measurements and their correlation with prediction of difficult laryngoscopic view

INTRODUCTION: Preoperative assessment of various anatomic and clinical features helps in identifying potentially difficult laryngoscopy and intubation in advance allowing the anesthetist to be prepared for such a scenario. Though “ Short Neck” is a commonly used term in airway assessment indicating the possibility of a difficult airway. there is a lack of clarity regrading the cut off value and the association of different neck lengths (Anterior, Posterior and Lateral) to the laryngoscopic view. AIM : Evaluation of anterior, posterior and lateral neck length in neutral and extended positions and correlate each measurement with prediction of difficult laryngoscopic view. MATERIALS AND METHODS : This prospective observational study was conducted on 150 patients belonging to American Society of Anesthesiologists (ASA) grade 1/11 , aged 18-65 years with body mass index (BMI) 18 to 35 kg/m2,scheduled to undergo elective surgeries under general anaesthesia with endotracheal intubation. Each subject’s anterior,lateral and posterior neck lengths (ANL,LNL,PNL) were measured pre operatively. Direct laryngoscopy was done to achieve the best Cormack Lehane(CL) grade using manoeuvres (Backward upward rightward manoeuvre(BURP)/OELM/Change of Blade/Change of pillow height/RAMP positioning) when indicated and the same compared to the measured neck lengths. RESULT : The incidence of difficult laryngoscopy was found to be 18 per cent in our study population. Anterior neck length in neutral position was found to be the best predictor of difficult laryngoscopy, with a threshold of less than or equal to 9 cms. No particular neck length correlated with BMI and age. All the neck lengths showed positive correlation with the height of the subject CONCLUSION : ANL with a cut off criterion of less than or equal to 9 cm in neutral position can used objectively when measuring neck length. All neck lengths showed significant change with neck mobility. Rate of change of both PNL and LNL with head extension position showed significant change in difficult laryngoscopy subjects.

Predicting Difficult Laryngoscopy by Ultrasound Quantification of Anterior Neck Soft Tissue Thickness-A Prospective Observational Study

Introduction: Difficult airway can possess a challenge to intubation and deciding role in morbidity and mortality. Hence, at these times Ultrasonography (USG) can play a vital role in the prediction of a difficult airway. Aim: To determine if USG measurement of anterior neck soft tissue thickness at the hyoid bone, and anterior commissure levels can be used to predict difficult laryngoscopy. Materials and Methods: The prospective observational study was carried out from January 2021-January 2022. There were 50 patients, aged 20-60 years, and scheduled to undergo general anaesthesia. Correlation analysis between roles of screening tests like Mallampati scoring (MMP), Cormack Lehane (CL) grade Neck Circumference (NC), Thyromental Distance (TMD) and USG measurements was done for predicting difficult laryngoscopy. Portable USG machine with a linear frequency probe, measuring tape and laryngoscope blade was required. The data was analysed using Statistical Package for Social Sciences (SPSS) version 22. Results: The incidence of difficult laryngoscopy was 18% and the mean age of the study participants in the easy group was 44.26 years and in the difficult group it was 45.13 years. The USG measurements were significant (p-value=0.01) in determining difficult intubation, which shows greater validity to predict difficult laryngoscopy. Hence, USG measurement along with bedside screening test aids in better identification and assessment of difficult airway. Conclusion: Anterior neck soft tissue thickness measured by USG at the hyoid bone, and anterior commissure levels combined with the screening tests and risk factors might increase the ability to predict difficult airways.

Comparison of Mallampati test in sitting position and in supine position for prediction of difficult tracheal intubation among adult patients who underwent surgery under general anesthesia at Addis Ababa governmental hospitals 2021, comparative cross-sectional study.

BackgroundThe Mallampati test is used to evaluate the airway to predict difficult laryngoscopy and intubation. The sitting position is the standard for this test, but it has limited practical utility due to its low sensitivity and moderate specificity in predicting difficult intubation and laryngoscopy. The supine position, on the other hand, may improve its efficacy.ObjectiveTo assess the Mallampati test in sitting and supine positions on predicting difficult laryngoscopy and intubation among Adult surgical patients undergoing general anesthesia in selected governmental hospitals of Addis Ababa.MethodA cross-sectional study was conducted on 403 adult patients who underwent surgery that required endotracheal intubation. The preoperative Mallampati test in sitting and supine positions was compared to the Cormac and Lehan grade and Intubation Difficulty Scale using the chi-square test. The Statistical Package for Social Sciences (SPSS) software version 26.0 was used to analyze the data. A p-value of less than 0.05 was used to determine statistical significance. As statistical measurements, sensitivity, specificity, positive predictive values, and negative predictive values were calculated.ResultThe incidence of difficult laryngoscopy and intubation is 13.7% and 9.7% respectively. Supine positions show a sensitivity of 78.8%; specificity of 93%; a positive predictive value of 64.1 and a negative predictive value of 96. Whereas sitting shows sensitivity of 75%; specificity of 96.3%; positive predictive value of 76.5 and negative predictive value of 96 concerning difficult laryngoscopy. Related to difficult intubation supine shows a sensitivity of 78.4%; 89.8% specificity; 45.3 positive predictive value and 97.5 negative predictive values, whereas sitting shows 73% sensitivity, 93% specificity, 52.9% positive predictive value and 97% negative predictive value.Conclusionand recommendation: For predicting difficult tracheal intubation and laryngoscopy, sitting has a high specificity and positive predictive value, but supine has high sensitivity and negative predictive value. Despite its poor positive predictive value, supine has a comparable prediction for difficult intubation therefore it can be used as an alternative approach.

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.

Effects of mandibular distraction osteogenesis on anesthetic implications in children with hemifacial microsomia.

Hemifacial microsomia (HFM) is a congenital craniofacial malformation, and its features include hypoplasia and asymmetry in skeletal tissue and soft tissue. These features are usually associated with a difficult airway. Mandibular distraction osteogenesis can achieve mandibular advancement, but its effect on the subsequent laryngoscopic views has not been adequately documented. The aim of this study was to determine the change in laryngoscopic views after mandibular distraction osteogenesis (MDO) in children with HFM and to examine the radiological changes after MDO by using computed tomography (CT)-based three-dimensional (3-D) airway reconstruction. An observational prospective study was carried out in children with HFM undergoing MDO. All children underwent 3-D airway reconstruction preoperatively before the placement and removal of the distractor. The temporomandibular joint lesions in children were classified by the Pruzansky-Kaban classification. The Cormack-Lehane grade was assessed after induction under direct laryngoscopy. The relationship between difficult laryngoscopy and the Pruzansky-Kaban classification was assessed. Changes in the upper pharyngeal airway parameters and laryngoscopic views were analyzed. Forty children (ages ranging from 5 to 16 years, males=26, females=14) with HFM underwent 80 anesthesia for MDO. The incidence of difficult laryngoscopy before mandibular distraction was 5/12 (41.7%) in type IIa, 19/24 (79.2%) in type IIb and 1/4 (25%) in type III HFM. The mean difference in the incidence of difficult laryngoscopy before and after MDO was 33.3% (95% CI: -6.7% to 73.3%), 50.0% (95% CI: 8.4% to 91.6%), and 0% for type IIa, type IIb, and type III, respectively. In type IIb, 12/19 cases of difficult laryngoscopy became easy after mandibular distraction: this was associated with an increase in the palatopharyngeal and glossopharyngeal CT parameters (p < .05). In type IIa, 5/5 cases of difficult laryngoscopy became easy after mandibular distraction, and 1/7 cases of easy laryngoscopy became difficult laryngoscopy. However, there were no significant changes in the palatopharyngeal, glossopharyngeal, and hypopharyngeal CT parameters in type IIa and type III HFM (p>.05). MDO can improve the laryngoscopic views in children with HFM. According to the Pruzansky-Kaban classification, children with type IIb showed the highest incidence of difficult laryngoscopy before MDO. After MDO, the improvement in laryngoscopic views under direct laryngoscopy in type IIb was related to the increase in the palatopharyngeal and glossopharyngeal volume.

A study on incidence of difficult laryngoscopy and intubation using modified Mallampatti test during pre-operative assessment of patients

Various clinical techniques have been used to assess difficult laryngoscopy, some of which are not sensitive or specific to predict difficult intubation. Hence unidentified difficult intubation can be challenging to the anesthesiologist. All patients were premedicated with Tab. Pantoprazole 40 mg given orally night before surgery. On the morning of surgery patient were shifted to the O.T, Non- Invasive Blood pressure, ECG, Spo2 monitors were connected and basal vitals were recorded. Patients were given Inj Fentanyl 2µg/kg, Inj Midazolam 25 µg/kg given IV and pre oxygenated for 3 mins. Mallampatti grade 3&4 were considered as predictors of difficult intubation. There were 29 cases out of 300 patients (9.7%) belong to Mallampatti Grade 3 & 4.

Prediction of difficult laryngoscopy in school-aged patients with microtia.

Children with microtia may experience difficult laryngoscopy because the ear and the mandible develop from the first and second bronchial arches and clefts. In this prospective observational study, we enrolled 166 patients (6-14 years old) with microtia scheduled for auricular reconstruction with autologous costal cartilage framework. Airway of the subjects was assessed preoperatively with the Modified Mallampati classification, Thyromental distance, Interincisor gap, Forward protrusion of the mandible and Horizontal length of the mandible. Anesthesiologist performed the direct laryngoscopy. Difficult laryngoscopy was classified as grade III or IV based on the Cormack-Lehane classification. A total of 166 patients completed the study, including 158 (95%) isolated microtia patients and 8 (5%) hemifacial microsomia patients. The incidence of difficult laryngoscopy was 34/166 (20.5%) in all patients, 3/8 (37.5%) in hemifacial microsomia patients, 31/158 (19.6%) in isolated microtia patients (P=0.35). Multivariate logistic regression shows that Thyromental distance, Interincisor gap, Forward protrusion of the mandible are all independent predictors of difficult laryngoscopy. The sensitivity and specificity of each predictor were: Thyromental distance (82.35%, 89.39%), Interincisor gap (58.82%, 86.36%), and Forward protrusion (17.65%, 97.73%), respectively. The cutoff values of Thyromental distance and Interincisor gap for prediction of difficult laryngoscopy were 4.0 cm and 3.3 cm. The best combination of predictors was Thyromental distance/Interincisor gap/Forward protrusion of the mandible with a sensitivity of 94.12% and specificity of 86.36%. The combination of Thyromental distance, Interincisor gap, and Forward protrusion of the mandible is the optimal assessment to predict difficult laryngoscopy in school-aged patients with microtia.

Ultrasonographic prediction of difficult laryngoscopy in obese patients

Introduction: Anticipation of difficulties in airway management is of prime importance in avoiding potential catastrophies. Obese patients form part of a population that is believed to have difficult airway. Ultrasound imaging has recently come forth as a simple, portable, noninvasive adjunct for bedside assessment. We hypothesized that there is an association between ultrasonographic measurements of the anterior neck soft-tissue thickness at level of vocal cords (VCs) and hyoid bone (HB) in predicting difficult laryngoscopy in the obese patients and evaluated the feasibility of ultrasound in predicting difficult laryngoscopy in Indian population. Materials and Methods: A total of 70 obese patients with body mass index >30 kg/m2 and American Society of Anesthesiologists Grade I and II undergoing elective surgeries and receiving general anesthesia were enrolled in the study. Ultrasound quantification of the anterior neck soft tissue was performed using a high-frequency (13–6 MHz) linear transducer. The distance from the skin to the anterior aspect of the trachea was measured at two levels: VCs and HB. Results: The incidence of difficult laryngoscopy (III and IV) in our study population was 24.3% (17 of 70 cases). The sonographic measurements of the skin thickness of the anterior neck were greater at the level of VCs in the difficult laryngoscopy group at 13.5 ± 1.5 mm as compared to the easy laryngoscopy group at 10.2 ± 1.6 mm, with the difference being statistically significant, P

How to Predict Difficult Tracheal Intubation: The Application of Acromio-axillo-suprasternal Notch Index.

Background:The incidence of difficult laryngoscopy or tracheal intubation is high, which needs a method to predict the difficulty of tracheal intubation to decrease the rate of complications. Therefore, the aim of this study was to evaluate acromio-axillo-suprasternal notch index (AASI) method for predicting difficult tracheal intubation and difficult laryngoscopy.Materials and Methods:This cross-sectional and diagnostic value study was performed on 108 patients who had indication for endotracheal intubation in the emergency department. Before endotracheal intubation, AASI was evaluated in all patients. The sensitivity, specificity, and total accuracy for predicting the power of AASI for the difficulty of tracheal intubation were measured.Results:Based on Cormack and Lehane grading system, 54 patients had easy endotracheal intubation (33.3% Grade I and 66.6% Grade II) and 52 patients had difficult endotracheal intubation (57.7% Grade III and 32.7% Grade IV). The sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy for AASI in cutoff point 0.515 for predicting difficulty of endotracheal intubation with 0.857 area under the receiver operating characteristic curve were 84.6%, 77.7%, 78.5%, 84%, and 81.13%, respectively.Conclusions:Our results showed that predicting difficulty of endotracheal intubation by AASI is accurate and with high sensitivity and specificity values, therefore, training this method to emergency physicians should be considered in our country or other countries. Further studies are required to confirm our findings.

Effect of Head Elevation to Different Heights in Laryngeal Exposure with Direct Laryngoscopy.

The purpose of this study was to determine the optimal pillow height for the best laryngoscopic view in adult patients scheduled for elective surgery under general anaesthesia. 150 adult patients undergoing surgery under general anaesthesia with endotracheal intubation with no features suggestive of difficult airway were enrolled for the study. After induction of anaesthesia the assessment of direct laryngoscopic views was done at head positions without a pillow and with non-compressible pillows of heights 5cm and 10cm. The laryngoscopic view with the 5cm pillow was significantly superior to other head position (p<0.01). The incidence of difficult laryngoscopy (Cormack and Lehane grade III) was 32.7% without a pillow which improved to (Cormack and Lehane grade III) 4% with 10cm pillow and there were no cases of difficult laryngoscopy with 5cm pillow. The use of 5cm pillow in the 'sniffing' position obtains the best laryngoscopic view during direct laryngoscopy.

Comparison of thyromental height test with ratio of height to thyromental distance, thyromental distance, and modified Mallampati test in predicting difficult laryngoscopy: A prospective study.

Background and Aims:Preoperative airway assessment to predict patients with difficult laryngoscopy is always crucial for anesthesiologists. Several predictive tests have been studied by various authors in quest of finding the best airway predictor. Recently, a new airway predictor, thyromental height test (TMHT) has been reported to have good predictive value in assessing difficult airway. We conducted this study with primary aim to evaluate the diagnostic accuracy of TMHT and to compare it with other established airway predictors, such as ratio of height to thyromental distance (RHTMD), thyromental distance (TMD), and modified Mallampati test (MMT) for predicting difficult laryngoscopy.Material and Methods:This prospective, observational study was conducted in 550 patients of either sex aged >18 years scheduled for elective surgery under general anesthesia. The patients’ airway was assessed preoperatively by two anesthetists. Standard anesthetic protocol was followed in all the patients. The laryngoscopic view was graded according to Cormack–Lehane scale. The receiver operating characteristic (ROC) curve was used to calculate the ideal cut off values for TMHT and RHTMD. Standard formulae were used to calculate validity indexes.Results:The incidence of difficult laryngoscopy was 10%. The cut-off value for TMHT and RHTMD were 5.1 cm and 19.5, respectively. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of TMHT were 78.18%, 93.94%, 58.90%, and 97.48%, respectively. The highest sensitivity, PPV, and NPV were observed with TMHT as compared with RHTMD, TMD, and MMT (P < 0.0001).Conclusions:TMHT is the best predictive test with highest accuracy and odds ratio for predicting difficult airway out of all predictive tests evaluated.

The bariatric airway.

The prevalence of obesity in the UK is increasing. Airway management in the obese patient can be challenging. Face mask ventilation is frequently difficult, and while the incidence of difficult laryngoscopy is only marginally raised, the consequences of failed intubation and the rate at which the obese patient desaturates makes this an unforgiving population. Emergence from anaesthesia requires particular care and attention. This article addresses the problems of airway management in the obese patient and looks at measures which can be taken to overcome them.

Correlation of Neck Circumference with Difficult Mask Ventilation and Difficult Laryngoscopy in Morbidly Obese Patients: an Observational Study.

Mask ventilation and laryngoscopy can be challenging in morbidly obese patients because of excessive fat tissue. There are studies suggesting that neck circumference is associated with difficult mask ventilation, difficult laryngoscopy, and difficult intubation. The primary aim of our study is to evaluate predictive value of neck circumference for difficult mask ventilation and difficult laryngoscopy in female and male morbidly obese patients separately. This observational cross-sectional study was performed in the period between March 2015 and December 2015. One hundred and twenty (37 male and 83 female) patients undergoing elective surgery were included. Neck circumference, BMI, Mallampati scores, neck movements, dentition, upper lip bite test, breast, thorax, waist, hip circumferences, mouth opening, and sternomental and thyromental distances were evaluated preoperatively. Mask ventilation was graded using four-grade classification. Laryngoscopy was evaluated by Cormack Lehane score. The incidence of difficult mask ventilation was 13.5% in male and 3.6% in female patients. Mouth opening ≤ 6.5cm and inadequate flexion were found as significant predictors for difficult mask ventilation in male patients. The incidence of difficult laryngoscopy was 10.8% in male and 4.8% in female patients. Mallampati score > II was found as a significant predictor for difficult laryngoscopy in both male and female patients. Sternomental distance ≤ 16cm and inadequate flexion were also significant predictors for difficult laryngoscopy in male patients. Neck circumference was not found statistically significant predictor for difficult mask ventilation and laryngoscopy in morbidly obese patients in our study. Neck circumference is not a statistically significant predictor for difficult mask ventilation and laryngoscopy in morbidly Turkish obese male and female patients. NCT02589015.

Accuracy of modified thyromental height in predicting difficult laryngoscopy

Objective To evaluate the accuracy of modified thyromental height (MTMH) in predicting difficult laryngoscopy. Methods Two hundred and sixty-three patients of both sexes requiring endotracheal intubation, aged over 17 yr, with body mass index less than 33 kg/m2, of American Society of Anesthesiologists physical status Ⅰor Ⅱ, scheduled for elective surgery under general anesthesia, were selected.The modified Mallampati test (MMT) score, thyromental height (TMH) and MTMH( sniffing thyromental height) were assessed after admission to the operating room.MMT grade Ⅲ or Ⅳ was set as positive predicting index.Direct laryngoscope was placed after induction of anesthesia to expose the glottis, and difficult laryngoscopy was defined as Cormack-Lehane grade Ⅲ or Ⅳ after external laryngeal manipulation.The area under the receiver operating characteristics curve (AUC) was used to evaluate the accuracy of MMT, TMH and MTMH in predicting difficult laryngoscopy. Results Difficult laryngoscopy was found in 24 patients and non-difficult laryngoscopy in 239 patients, the incidence of difficult laryngoscopy was 10.0%, and there were no failed intubations.The AUC (95% confidence interval) of MTMH in predicting difficult laryngoscopy was 0.966 (0.396-0.984), the best cut-off value was 46.83 mm, and Youden index was 0.8456.The sensitivity and specificity of MTMH in predicting difficult laryngoscopy was 91.67% and 92.89%, respectively, and the odds ratio was 143.647.The AUC of MTMH in predicting difficult laryngoscopy was significantly enlarged when compared with that of MMT and TMH (P<0.05). Conclusion MTMH can accurately predict difficult laryngoscopy with the best cut-off value of 46.83 mm in patients. Key words: Thyroid cartilage; Chin; Intubation, intratracheal

Bedside clinical tests as a screening tool for predicting difficult laryngoscopy and intubation: An observational study

Context: Morphological characteristics of the airway in a population have regional variations making airway assessment and management a crucial aspect of anaesthesia practice. Aims: (1) To determine the incidence of difficult laryngoscopy and intubation using Cormack–Lehane grading and Intubation Difficulty Scale (IDS). (2) To assess the accuracy of bedside clinical tests in predicting difficult laryngoscopy and intubation. Settings and Design: Prospective observational study was carried out on 200 patients aged 18–70 years, undergoing planned surgical procedures under general anaesthesia requiring endotracheal intubation. Pregnant women, patients with head-and-neck pathology, and patients with trauma were excluded from the study. Patients and Methods: All patients underwent preoperative airway assessment and standard induction procedure. Cormack–Lehane grading was noted during first laryngoscopy and process of intubation evaluated by IDS. Statistical Analysis Used: Descriptive statistics used to depict baseline profile. Chi-square, Student t -test and logistic regression used to determine adjusted effects. Analysis was performed using STATA (14.2). Results: The incidence of difficult laryngoscopy was 15.5% and difficult intubation was 12.5%. Univariate analysis showed body mass index (BMI) >25 kg/m 2 , neck circumference (NC) >36 cm and modified Mallampati score 3/4 as significant predictors. Logistic regression showed interincisor gap (IIG) ( P P Conclusions: NC and IIG are rapid, simple bedside tests to predict difficult intubation. Bedside clinical tests have poor discriminative power but still have a role in choosing alternative methods for airway management, making judicious use of time and resources while causing minimum discomfort to the patient.

Ratio of height to thyromental distance as a predictor of difficult laryngoscopy: A prospective observational study.

Background and Aim:Various airway indices are used either singly or in combination to predict difficult laryngoscopy. Recently introduced ratio of height to thyromental distance (RHTMD) is reported to have better predictability. We aimed to assess the prediction of difficult laryngoscopy by RHTMD and compared it with other indices.Material and Methods:In this prospective, single-blinded comparative observational study, 300 adult patients of either gender scheduled to receive general anesthesia were assessed. Airway indices, like RHTMD, thyromental distance, modified Mallampati test, and upper lip bite test, were assessed and correlated with Cormack and Lehane's laryngoscopic grading. The validity parameters like specificity, sensitivity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated for each test. Effect of combining all the indices was also analyzed. Receiver operating characteristic curves were constructed and optimal cutoff value for the quantitative indices was calculated.Results:The incidence of difficult laryngoscopy in our study was 5.33%. Of the four indices, the single best test was RHTMD, with better sensitivity, high specificity, NPV, and accuracy and with good PPV. A combination of all the indices resulted in 100% sensitivity and higher specificity.Conclusions:RHTMD is a single best preoperative test for predicting difficult laryngoscopy. A combination of tests has higher sensitivity and specificity with better discriminative power. Therefore indices should be used in combination in the preoperative airway assessment of adult patients.