Thyromental Distance Research Articles

The Evaluation of Thyromental Height Test as a Single, Accurate Predictor of Difficult Laryngoscopy.

Thyromental Height Test is a relatively new, easy method considered as a more accurate predictor of difficult laryngoscopy than existing methods. The aim of this study was to evaluate its accuracy in predicting difficult laryngoscopy as compared to commonly used methods. This hospital based, cross-sectional, observational study was conducted on 246 patients scheduled for surgery under general anesthesia with endotracheal intubation. Airway assessment was done during pre-anesthetic assessment by Thyromental Height Test, Modified Mallampati Test, Thyromental Distance and Sternomental Distance measurements and predicted as 'difficult' or 'easy' laryngoscopy based on accepted cut-off values. Direct laryngoscopic view was assessed after administration of general anesthesia by a laryngoscopist unaware of the pre-anesthetic assessments and recorded as 'actual' difficult or easy laryngoscopy based on Cormack-Lehane grades. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of each clinical test were determined. Thyromental Height Test had the highest sensitivity (71.42%) and negative predictive value (98.9% respectively) but lowest accuracy (77.2%). Maximum specificity was observed with Thyromental Distance and Sternomental Distance (97.49% each). Thyromental Distance had the highest positive predictive value (25%) and accuracy (95.52%). Thyromental Height Test, with its high sensitivity, is a useful predictor of difficult laryngoscopy. However, due a high number of false positives and relatively low accuracy, it cannot be considered as a sole, reliable and accurate predictor of difficult laryngoscopy.

Implementation and initial validation of a multicentre obstetric airway management registry

Background: In Africa, maternal mortality after caesarean delivery is 50 times greater than in high-income countries. In South Africa, more than 50% of anaesthesia-related maternal mortality is attributed to failure to protect the airway. We implemented an obstetric airway management registry, to facilitate future improvements in management and outcomes. Methods: A prospective electronic registry was established at three obstetric sites in Cape Town, recording airway management for all general anaesthetics from 20 weeks gestation to seven days post-partum. Perioperative descriptive data are entered using a web-based smartphone-enabled platform. To quantify the reliability of capture, we compared the first 200 records in the registry to theatre logbooks. We used summary statistics to describe our obstetric anaesthesia population, and details relevant to airway management. Results: The first 200 cases were recorded from September 2018 to January 2019. According to theatre logbooks, this represented 80% of cases performed. Major indications for general anaesthesia included severe fetal distress/bradycardia (21%), failed neuraxial technique (19%), coagulopathy (19%), and abnormal placentation (12%). A third of patients had hypertensive disorders of pregnancy, and 6% had imminent/confirmed eclampsia. Forty per cent were in active labour. On airway assessment, Mallampati grade was 3 or 4 in 29% of patients, and mouth opening, thyromental distance and mandibular protrusion limited in 10%, 8% and 8% respectively. Cormack-Lehane grade IIb and III views were encountered in 6% and 2% respectively, with no grade IV views. Desaturation below 90% occurred in 12% of patients. There were two cases (1%) of failed intubation with supraglottic airway rescue, and no emergency surgical airways performed. Conclusion: An obstetric airway management registry was successfully implemented. Clinically significant hypoxaemia occurred commonly during general anaesthesia, with a high incidence of difficult intubation predictors and desaturation. The registry will guide research aimed at improving safety during general anaesthesia in obstetrics.

The Role of Indirect Laryngoscopy, Clinical and Ultrasonographic Assessment in Prediction of Difficult Airway.

Pre-operative airway evaluation is essential to decrease the proportion of possible mortality and morbidity due to difficult airway (DA). The study aimed to evaluate the accuracy of pre-operative ultrasonographic airway assessment (UAA) and indirect laryngoscopy (IL) in predicting DA. Prospective obsevational study. Preoperative clinical examination (body mass index [BMI], mallampati classification [MP], thyromental distance, sternomental distance, neck circumference), UAA (epiglottis-skin distance [ESD], hyoid bone-skin distance [HSD], the thickness of tongue root [ToTR], anterior commissure-skin distance [ACSD]) and IL with the rigid 70-degree laryngoscope were performed to predict DA (Cormack-Lehane grade 3 and 4). The sensitivity, specificity, positive predictive value (PP), and negative predictive values of the parameters were assessed. Twenty-two of 140 (15.7%) patients were diagnosed with DA. The cut-off points of ESD, HSD, ToTR, ACSD, and BMI were 2.09 cm, 0.835 cm, 4.05 cm, 0.545 cm, and 27.10, respectively. AUC values were 0.874, 0.885, 0.871, 0.658, and 0.751 in the same order. AUC values for IL and MP were 0.773 and 0.925, respectively. MP and HSD had the best sensitivity (91%), IL grading had the best specificity (100%), and PP (100%) value among all measurements. The best-balanced sensitivity (91%), specificity (97%), and PP (88%) values were obtained by combining the IL with MP and ESD or with MP and HSD. Ultrasonographic measurements and IL were found significantly correlated to predict DA. Combined parameters, the IL with MP and ESD or with MP and HSD, are the best parameters in predicting the DA. 4 Laryngoscope, 131:E555-E560, 2021.

English

English

Comparison of acromio-axillo-suprasternal notch index with upper lip bite test and ratio of height to thyromental distance for prediction of difficult intubation: a prospective study

The Sri Lankan Journal of Anaesthesiology is the official journal of the College of Anaesthesiologists of Sri Lanka. It publishes clinical investigations, research articles, audits, case reports, review articles and CME articles relating to anaesthesiology, critical care and pain. It is published bi annually in January and June. Sri Lankan Journal of Anaesthesiology is included on DOAJ and Scopus.

Assessment of Difficult Intubation Predictors in Different Populations of Turkey

Difficult tracheal intubation is defined when tracheal intubation requires multiple attempts, in the presence or absence of tracheal pathology. Most importantly, difficult intubation differs between countries and populations. Physicians should be aware of difficult intubation frequencies of their populations. Turkey is a transit country between East and West. Eastern Turkey reflects the Middle East and Asia, while western Turkey has European features. Our objectives were to investigate the frequency of difficult intubation in different regions’ populations, and specificity and sensitivity of predictive values. According to the population in the regions, 24 experienced anesthesiologists from 13 hospitals in 7 regions, were included in the study. Of 1313 patients, 143 patients (10.89%) were detected as difficult intubation. Mallampathy (MLP) III-IV were alone (p = 0.043), and the combination of thyromental distance <6 cm and MLP III-IV (p: 0.018) were statistically significant in difficult and easy intubation patient groups. The specificity was 97.46% in MLP + thyromental combination, and 98.05% in MLP + mouth opening combination. Western region had the shortest measurements in sternomental, thyromental and mouth opening (p <0.05), and had the most difficult intubation frequency compared to the other regions (p: 0.001). The positive predictive values were increased with increasing combinations, but further research is needed on the predictors of difficult intubation.

Concurrent Use of Videolaryngoscope and Fiberoptic Bronchoscope in a Child with Neurofibromatosis to Facilitate Endotracheal Intubation

IntroductionIn children who have craniofacial asymmetry secondary to neurofibromatosis type 1, the securing of the airway can be challenging. These patients have varying degrees of head and neck tumors that complicate endotracheal intubation. Anesthesiologists have many techniques and devices that assist us in securing adult airways and these devices are available in pediatric sizes which can also be used to safely secure the smaller airways. CaseThis 13-year-old male patient with Neurofibromatosis presented with a 2 cm mouth opening, Mallampati IV assessment, and thyromental distance of 2 cm for surgery. During the previous management of this child's airway it was found to be difficult using the fiberoptic bronchoscope or the Glidescope alone. DiscussionThis is a case report of improvement of intubating conditions using both devices concurrently.

The "BURP" maneuver improves the glottic view during laryngoscopy but remains a difficult procedure.

ObjectiveWe investigated the “BURP” maneuver’s effect on the association between difficult laryngoscopy and difficult intubation, and predictors of a difficult airway.MethodsAdult patients who underwent general anesthesia and tracheal intubation from September 2016 to May 2018 were included. The “BURP” maneuver was performed when glottic exposure was classified as Cormack–Lehane grade 3 or 4, suggesting difficult laryngoscopy. The thyromental distance, modified Mallampati score, and interincisor distance were assessed before anesthesia.ResultsAmong this study’s 2028 patients, the “BURP” maneuver decreased difficult laryngoscopies from 428 (21.1%) to 124 (6.1%) cases and increased the difficult intubation to difficult laryngoscopy ratio from 53/428 (12.4%) to 52/124 (41.9%). For laryngoscopies classified as difficult without the “BURP” maneuver, the area under the curve (AUC) of the thyromental distance, modified Mallampati score, and interincisor distance was 0.60, 0.57, and 0.66, respectively. In difficult laryngoscopies using the “BURP” maneuver, the AUC of the thyromental distance, modified Mallampati score, and interincisor distance was 0.71, 0.67, and 0.76, respectively.ConclusionsThe “BURP” maneuver improves the laryngoscopic view and assists in difficult laryngoscopies. Compared with difficult laryngoscopies without the “BURP” maneuver, those with the “BURP” maneuver are more closely associated with difficult intubations and are more predictable.Trial registration: www.chictr.org.cn identifier: ChiCTR-ROC- 16009050.

Comparison of the Upper Lip Bite Test (ULBT) with the Ratio of Height to Thyromental Distance (RHTMD) for the Prediction of Difficult Laryngoscopy in Apparently Normal Patients

Comparison of the Upper Lip Bite Test (ULBT) with the Ratio of Height to Thyromental Distance (RHTMD) for the Prediction of Difficult Laryngoscopy in Apparently Normal Patients

Avaliação de testes à beira leito e proposta de modelo para prever laringoscopia difícil: estudo prospectivo observacional

Background and objectivesThe prediction of difficult laryngoscopy is based on tests that assess anatomic characteristics of face and neck. We aimed to identify the most accurate tests and propose a multivariate predictive model. MethodsThis prospective observational study included 1134 patients. Thyromental Distance (TMD), Sternomental Distance (STMD), Ratio of Height‐to‐Thyromental Distance (R‐H/TMD), Neck Circumference (NC), Ratio of Neck Circumference‐to‐Thyromental Distance (R‐NC/TMD), Hyomental Distance with head in Neutral Position (HMD‐NP) and at Maximal Extension (HMD‐HE), Ratio of Hyomental Distance at Maximal head extension‐to‐hyomental distance in neutral position (R‐HMD), Mallampati Class (MLC), Upper Lip Bite Test (ULBT), Mouth Opening (MO) and Head Extension (HE) were assessed preoperatively. A Cormack‐Lehane Grade ≥ 3 was defined as Difficult Laryngoscopy. Sensitivity, specificity, positive and negative predictive values were assessed for all tests. Multivariate analysis with logistic regression was used to create the predictive models. ResultsA model incorporating MLC, ULBT, HE, HMD‐HE and R‐NC/TMD showed high prognostic accuracy; x2(5)=109.12, p <0.001, AUC=0.86, p <0.001). Its sensitivity, specificity and negative predictive value were 82.3%, 74.8% and 97.4%, respectively. A second model including two measurements not requiring patient's cooperation (R‐NC/TMD and HMD‐HE) exhibited good prognostic performance; x2(2)=63.5, p <0.001, AUC=0.77, p <0.001. Among single tests, HE had the highest sensitivity (78.5%) and negative predictive value (96%). ConclusionsA five‐variable model incorporating MLC, ULBT, HE, HMD‐HE and R‐NC/TMD showed satisfyingly high predictive value for difficult laryngoscopy. A model including R‐NC/TMD and HMD‐HE could be useful in incapable patients. The most accurate single predictor was HE.

Evaluation of bedside tests and proposal of a model for predicting difficult laryngoscopy: an observational prospective study☆

Background and objectivesThe prediction of difficult laryngoscopy is based on tests that assess anatomic characteristics of face and neck. We aimed to identify the most accurate tests and propose a multivariate predictive model. MethodsThis prospective observational study included 1134 patients. Thyromental Distance (TMD), Sternomental Distance (STMD), Ratio of Height-to-Thyromental Distance (R-H/TMD), Neck Circumference (NC), Ratio of Neck Circumference-to-Thyromental Distance (R-NC/TMD), Hyomental Distance with head in Neutral Position (HMD-NP) and at Maximal Extension (HMD-HE), Ratio of Hyomental Distance at Maximal head extension-to-hyomental distance in neutral position (R-HMD), Mallampati Class (MLC), Upper Lip Bite Test (ULBT), Mouth Opening (MO) and Head Extension (HE) were assessed preoperatively. A Cormack-Lehane Grade ≥ 3 was defined as Difficult Laryngoscopy. Sensitivity, specificity, positive and negative predictive values were assessed for all tests. Multivariate analysis with logistic regression was used to create the predictive models. ResultsA model incorporating MLC, ULBT, HE, HMD-HE and R-NC/TMD showed high prognostic accuracy; x2(5) = 109.12, p < 0.001, AUC = 0.86, p < 0.001). Its sensitivity, specificity and negative predictive value were 82.3%, 74.8% and 97.4%, respectively. A second model including two measurements not requiring patient’s cooperation (R-NC/TMD and HMD-HE) exhibited good prognostic performance; x2(2) = 63.5, p < 0.001, AUC = 0.77, p < 0.001. Among single tests, HE had the highest sensitivity (78.5%) and negative predictive value (96%). ConclusionsA five-variable model incorporating MLC, ULBT, HE, HMD-HE and R-NC/TMD showed satisfyingly high predictive value for difficult laryngoscopy. A model including R-NC/TMD and HMD-HE could be useful in incapable patients. The most accurate single predictor was HE.

Comparison of Upper Lip Bite Test with Modified Mallampati Test and Thyromental Distance for Prediction of Difficult Intubation

Introduction: The prediction of difficult intubation using simple bedside test is of great importance to prevent mismanagement of airway. This study was conducted to compare Upper Lip Bite Test (ULBT) with Modified Mallampati Test (MMT) and Thyromental Distance (TMD) for the prediction of difficult intubation.&#x0D; Method: This was descriptive cross-sectional study conducted in 121 patients of American Society of Anaesthesiologists Physical Status (ASA PS) I and II patients scheduled for elective surgery requiring general anaesthesia with endotracheal tube. The airway assessment of the patients was done one day prior to the surgery using Upper Lip Bite Test (ULBT), Modified Mallampati Test (MMT) and measurement of Thyromental Distance (TMD) . On the day of surgery during laryngoscopy, Cormack-Lehane (CL) grading was recorded. The CL grading of III and IV was labeled as difficult intubation. The Sensitivity, Specificity, Positive Predictive Value (PPV), Negative Predictive Value (NPV), Likelihood Ratio (LR) of ULBT, MMT and TMD were calculated and compared.&#x0D; Results: The total percentage of difficult intubation, defined by Cormack-Lehane (CL) III and IV was 16.52 %. The sensitivity, specificity, PPV, NPV and accuracy of Upper Lip Bite Test (ULBT) was 50%, 100%, 100%, 91% and 91.74% respectively. ULBT had a significantly higher sensitivity, specificity and PPV when compared to MMT or TMD or MMT and TMD when combined together.&#x0D; Conclusions: Upper Lip Bite Test (ULBT) is better predictor of difficult intubation and it should be used along with other test during airway assessment.

Ultrasonography for predicting a difficult laryngoscopy. Getting closer.

Our objective was to evaluate the usefulness of five ultrasound measurements to predict a difficult laryngoscopy (DL). Prospective observational study. 50 patients underwent scheduled surgery under general anesthesia with orotracheal intubation with classical laryngoscopy at the University Hospital of Jaén (Spain). Sociodemographic variables, classic preintubation screening tests and ultrasound measurements of the neck soft tissue from skin to hyoid (DSH), epiglottis (DSE) and glottis (DSG) were obtained, as well as two measurements derived from the above: DSH + DSE and DSE - DSG. The relationship between a DL and ultrasound measurements was evaluated using t student test. The ROC Curve was used to establish the diagnostic accuracy of ultrasound measurements to discriminate a DL and logistic regression was used to establish a cut-off point. Multivariate analysis was performed to assess the impact of these measures in clinical practice. Patients with DL showed greater thickness of DSE (2.9 ± 0.46cm vs 2.32 ± 0.54cm; p = 0.001), DSH + DSE (4.25 ± 0.45 cm vs 3.62 ± 0.77cm; p = 0.001) and DSE - DSG (1.83 ± 0.54 cm vs 1.24 ± 0.46 cm; p = 0.001) than those with an easy laryngoscopy. DSE and DSE - DSG had the highest diagnostic accuracy for DL with an area under the ROC curve of 0.79 [95%IC 0.66-0.92] and 0.82 [95%IC 0.68-0.96], respectively. It was established that DSE ≥ 3cm, could predict a DL with a positive predictive value (PPV) of 69.23% [95%CI 40.3-98.2], and DSE - DSG ≥ 1.9cm would do so with a PPV of 78.57% [95%CI 53.31-100%]. The multivariate analysis endorsed that DSE and DSE - DSG combined with classic tests (the Modified Mallampati score, the thyromental distance and the upper lip bite test) improved the preoperative detection of a DL. The inclusion of DSE and DSE - DSG in a multivariate model with classic parameters may offer the anesthesiologist better information for detecting a DL preoperatively.

Assessment of Airway Parameters for Predicting Difficult Laryngoscopy and Intubation in a Tertiary Center in Western Nepal.

The screening tests used for pre-operative evaluation of airway to predict difficult laryngoscopy and intubation have variable diagnostic accuracy. The unanticipated poor laryngeal view is gold standard for defining difficult intubation. We aimed to find out the prevalence of difficult laryngoscopy and intubation, which airway parameter better predicts difficult intubation and whether difficult laryngoscopy is associated with difficult intubation or not. This analytic cross sectional study was conducted in 665 ASA I/II adult patients, aged 18-65, without obvious airway pathology undergoing elective surgery under general anesthesia. The pre-operative screening tests included mouth opening, modified mallampatti, ratio of height to thyromental distance, sternomentaldistance and upper lip bite test. Cormack-Lehane grade III/ IV was defined as difficult laryngoscopy and potentially difficult intubation. Sensitivity, specificity, positive predictive value, negative predictive value, accuracy and area under curve at 95% confidence interval was calculated for all five screening tests. The prevalence of difficult laryngoscopy and intubation was 6.6% (44 cases). The upper lip bite test because of its highest specificity, positive predictive value, negative predictive value, accuracy and area under curve (99.7%; 93.9%; 99.7%; 95.2%; 85.1% respectively) with moderate level of sensitivity (70.5%) was better predictor of difficult intubation than other tests. The difficult laryngoscopy was associated with difficult intubation (p=0.00). The prevalence of difficult laryngoscopy and intubation was 6.6%.The upper lip bite test was a better predictor of difficult intubation and there was a significant association of difficult laryngoscopy with difficult intubation.

Patient factors associated with difficult flexible bronchoscopic intubation under general anesthesia: a prospective observational study.

Patient characteristics associated with difficult tracheal intubation using a flexible bronchoscope (FB) under general anesthesia have not been prospectively evaluated. This observational study aimed to identify demographic and morphologic factors associated with difficult FB intubation. We recruited 420 adult elective surgery patients undergoing tracheal intubation during general anesthesia. Patients characteristics were recorded including age, sex, weight, height, body mass index, American Society of Anesthesiologists physical status, history of snoring, obstructive sleep apnea, Mallampati score, upper lip bite test score, neck circumference and skinfold thickness, maximal neck flexion and extension angles, absence of teeth, Cormack and Lehane grade, presence of blood or secretions during intubation, as well as the inter-incisor, thyromental, sternothyroid, and manubriomental distances. The time (duration) needed to complete intubation (primary endpoint) and the number of attempts needed were correlated with these patient characteristics in a multivariable analysis. Intubation was successful on the first attempt in 409/420 patients (97%). Seven patients (1.7%) needed more than one attempt. Failure to intubate with the FB occurred in four patients (1%). A correlation was found between intubation duration and visibility impaired by secretions or blood (P < 0.001), higher neck skinfold thickness (P < 0.001), and larger endotracheal tube diameter (relative to a constant 5.5 mm FB; P < 0.001). The presence of secretions or blood that impair FB glottic visualization, a larger diameter endotracheal tube on the same size FB, as well as higher neck skinfold thickness may prolong the duration of FB intubation under general anesthesia. www.clinicaltrials.gov (NCT02769819); registered 5 May, 2016.

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.

Predictive parameters of difficult intubation in thyroid surgery: a meta-analysis.

Airway management is a fundamental goal for the anesthesiologist. The rate of difficult laryngoscopy in patients undergoing thyroid surgery ranges from 6.8% to 9.6%. An accurate and detailed preoperative evaluation of the airway seems to be a promising tool to predict a potentially difficult airway management. We aimed to identify possible risk factors and physical findings that predict difficult intubation in thyroid surgery. MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials (CENTRAL) were analyzed, and the reference lists from the retrieved articles and previous reviews were searched for additional studies. Difficult intubation was defined as Cormack and Lehane grade ≥3 or Intubation Difficulty Scale score >5 by direct laryngoscopy. Studies that used advanced airway devices or ultrasound-based airway management were excluded. Gender, Mallampati Score, interincisor gap, thyromental distance, body mass index, tracheal deviation, histology, mediastinal goiter, mandibular protrusion, neck circumference and neck movement were evaluated. Qualitative analysis has been conducted in case of insufficient data for an appropriate meta-analysis. Eight studies that evaluated the accuracy of clinical findings for identifying difficult intubation in thyroid patients were reviewed (5853 patients). Two authors independently screened articles, extracted data and assessed risk of bias. 7.21% [95% CI: 6.57-7.91%] of patients undergoing thyroid surgery were difficult to intubate. The physical examination findings that best predicted a difficult intubation included Mallampati Score ≥3 (positive odds ratio 4.75 [95% CI: 2.22-10.12]); shorter thyromental distance thresholds ranging from <6.5-<6 cm; OR 3.64 [95% CI: 1.9-7.01]); 'low' interincisor gap, defined as a critical distance between incisors (ranging from <3.5 - <4.4 cm; odds ratio 2.57 [95% CI: 1.83-3.62]); presence of tracheal deviation (positive odds ratio, 2.06 [95% CI: 1.58-2.69]); Body Mass Index >30 kg/m2 (odds ratio 1.95 [95% CI: 1.20-3.15]) and males (odds ratio 1.54 [95% CI: 1.21-1.95]). Histological examination positive for cancer didn't increase the risk for difficult intubation. For mediastinal goiter, mandibular protrusion, neck circumference and neck mobility only a qualitative analysis was performed. In thyroid patients, the presence of high Mallampati Score, shorter thyromental distance, interincisor gap, tracheal deviation (the unique thyroid pathology linked parameter), obesity and male gender were risk factors for difficult intubation. However, all these significant parameters should be used in preoperative assessment to anticipate difficult intubation in thyroid surgery.

Prediction of difficult intubation in apparently normal patients by combining modified mallampati test and thyromental distance: A prospective observational study

Introduction: Difficult intubation, often unexpected, remains a primary concern for the anesthesiologist. None of the bedside airway assessment tests have proven to be efficacious and highly predictive. This study was done to determine the sensitivity and specificity of Modified Mallampati test alone, Thyromental distance alone and in combination of both for predicting difficult intubation. Material and Methods: A prospective observational study was conducted in Universal College of Medical Sciences Teaching Hospital (UCMSTH), which involved 80 American Society of Anesthesiologist Physical Status (ASA PS) I patients undergoing elective surgeries under general anesthesia with endotracheal intubation. All patients were included for preoperative assessment by Modified Mallampati test alone and Thyromental distance measurement. The correlation between these tests and Cormack and Lehane laryngoscopic grading was done to find out the result. Results: Prediction of difficult intubation among 80 patients by Modified Mallampati test alone showed sensitivity of 72.7% and specificity of 98.6% whereas with Thyromental distance alone, showed sensitivity of 36.4% and specificity of 100%. When both predictors were combined, result showed sensitivity of 72.7% and specificity of 98.6% which was similar to that of Modified Mallampati test alone. Conclusion: This study concluded that sensitivity to predict difficult intubation was higher with Modified Mallampati test alone or in combination with Thyromental distance test whereas specificity was highest with Thyromental distance test alone.

Ultrasonography versus conventional methods (Mallampati score and thyromental distance) for prediction of difficult airway in adult patients

ABSTRACT Background The poor reliability of traditional screening tools to identify a potentially difficult airway makes the difficult laryngoscopy and tracheal intubation rate remains at 1.5–13%.The hypothesis is that fat pads affect the view during direct laryngoscopy so the increasing thickness of pretracheal soft tissue or pre-epiglottic space could be strong predictors of difficult laryngoscopy as the mobility of the pharyngeal structures is impaired. Upon that, we aimed to evaluate ultrasound-measured distance from skin to epiglottis for prediction of difficult laryngoscopy in Egyptian population. Methods This was a prospective single blind randomized clinical study conducted on 80 patients requiring general anesthesia.Preoperatively, airway evaluation was performed using three parameters including Mallampati score, thyromental distance and ultrasound-measured distance from skin to epiglottis at the level of thyrohyoid membrane. The primary outcome was to correlate ultrasound measured distance from skin to epiglottis with difficult laryngoscopy in Egyptian population using Cormack – Lehane grading. Results Difficult laryngoscopy group displayed greater thickness of the ultrasound measured distance from the skin to epiglottis(2 ± 0.3 cm versus 1.7 ± 0.3 cm; p = 0.002). The cut-off point for difficult laryngoscopy was >1.85 cm with sensitivity of 80%, specificity of 70.8% and area under the receiver operating characteristic curve was 0.759. Mallampati score and thyromental distance had poor area under the curve = (0.651, 0.670 respectively). Conclusion Our study revealed good correlation between ultrasonograohic measurement of the skin to epiglottis distance and Cormack-Lehane grade in Egyptian population, therefore it might be considered as a predictor of difficult laryngoscopy. Clinical trial number NCT03799055.

Predictors of difficult endotracheal intubation in the emergency department: a single-center pilot study

Background: Identifying patients who are at risk of difficult endotracheal intubation is crucial in the emergency department. Therefore, this study evaluated the incidence and predictive factors of difficult tracheal intubation in the emergency department. Methods: This was a 17-month prospective observational study. A difficult airway was defined as Cormack &amp; Lehane classification grades III and IV at the first attempt of intubation. Patients who visited the emergency department, underwent traditional endotracheal intubation from participating physicians, and provided informed consent by themselves or via their delegates were enrolled in this study. Univariate associations between patient characteristics and difficult endotracheal intubation were identified, and statistically significant factors were included in a multivariate binary logistic regression model. A generalized association plot was used to show the relationships between variables. Results: A total of 110 patients were enrolled in the study. The incidence of difficult intubation was 35.5% (39/110). In the difficult airway group, significantly higher body mass index (BMI), and incidence of double chin, thick short neck, Mallampati difficulty, small interincisor distance, small thyromental distance, and upper airway obstruction were noted on univariate analysis. A predictive formula for difficult tracheal intubation was successfully established by the combination of four independent predictors: BMI (odds ratio [OR] = 1.270), thyromental distance (OR = 0.614), upper airway obstruction (OR = 4.038), and Mallampati difficulty (OR = 5.163). A cutoff score of four maximized Youden’s index, providing sensitivity (79.5%) and specificity (81.7%) (95% CI: 0.794 to 0.938). Conclusions: We used four predictors of difficult tracheal intubation, namely, BMI, thyromental distance, upper airway obstruction, and Mallampati difficulty, to create a predictive formula. This formula could help emergency physicians to quickly identify and carefully manage patients with difficult endotracheal intubation and consult experts early if necessary.