Anterior Neck Soft Tissue Research Articles

Effectiveness of four ultrasonographic parameters as predictors of difficult intubation in patients without anticipated difficult airway.

BackgroundPredicting difficult intubation (DI) is a key challenge, as no single clinical predictor is sufficiently valid to predict the outcome. We evaluated the effectiveness of four upper airway ultrasonographic parameters in predicting DI. The validity of the models using combinations of ultrasonography-based parameters was also investigated.MethodsThis prospective, observational, double-blinded cohort trial enrolled 1,043 surgical patients classified as American Society of Anesthesiologists physical status I–III without anticipated difficult airway. Preoperatively, their tongue thickness (TT), invisibility of hyoid bone (VH), and anterior neck soft tissue thickness from the skin to thyrohyoid membrane (ST) and hyoid bone (SH) were measured by sublingual and submandibular ultrasonography. The logistic regression, Youden index, and receiver operator characteristic analysis results were reported.ResultsOverall, 58 (5.6%) patients were classified as DI. The TT, SH, ST, and VH had accuracies of 78.4%, 85.0%, 84.7%, and 84.9%, respectively. The optimal values of TT, SH, and ST for predicting DI were > 5.8 cm (sensitivity: 84.5%, specificity: 78.1%, AUC: 0.880), > 1.4 cm (sensitivity: 81%, specificity: 85.2%, AUC: 0.898) and > 2.4 cm (sensitivity: 75.9%, specificity: 85.2%, AUC: 0.885) respectively. VH had a sensitivity and specificity of 72.4% and 85.6% (AUC: 0.790). The AUC values of the five models (with combinations of three or four parameters) ranged from 0.975–0.992. ST and VH had a significant impact on the individual models.ConclusionsSH had the best accuracy. Individual parameters showed limited validity. The model including all four parameters offered the best diagnostic value.

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

Development of a scoring system for predicting difficult intubation using ultrasonography.

Background and Aims: Ultrasound measurement of anterior neck soft tissue thickness by skin to epiglottis distance (SED) has been shown to predict difficult laryngoscopy. In this study, we developed an airway scoring system incorporating SED into three clinical predictors and assessed whether it would improve accuracy in prediction of difficult intubation.Methods:Mentohyoid distance, mandibular subluxation, head extension and ultrasound measurement of skin to epiglottis distance were measured a day before surgery in 310 adult patients. During direct laryngoscopy, Cormack–Lehane grading was noted (Grade 1 and 2 = Easy, Grade 3 and 4 = Difficult). We constructed a score named MSH, which included mentohyoid distance, mandibular subluxation and head extension. Then, SED was added to the MSH score to form another new score named USED-MSH. Student's t-test, Mann-Whitney U test and Chi-square test or Fisher exact tests were used. Both scoring systems were compared under the receiver-operating characteristic curve and area under the curve (AUC) were calculated.Results:Difficult intubation was observed in 62/310 patients (20%). The AUC for USED-MSH score was greater than the MSH score (0.93, 95% CI [0.89–0.97] vs 0.76, 95% CI [0.69–0.84], P value <0.001). USED-MSH score had higher sensitivity (93.6% vs 59.7%) and lower specificity (85.9% vs 91.1%) with similar positive predictive value (62.7% vs 62.4%) in comparison with MSH score.Conclusion: An airway scoring system using the ultrasound measurements of skin-to-epiglottis distance along with the clinical predictors would be helpful in the prediction of difficult intubation.

Anterior neck soft tissue thickness for airway evaluation measured by MRI in patients with cervical spondylosis: prospective cohort study

ObjectivesAnterior neck soft tissue thickness, usually measured by ultrasound, is increasingly being investigated to predict difficult laryngoscopy, but the results have not been validated. Considering the conflicting measurement data, different...

PREDICTION OF DIFFICULT LARYNGOSCOPY BY ULTRASOUND GUIDED VALUATION OF ANTERIOR NECK SOFT TISSUE THICKNESS.

10Feb 2019 PREDICTION OF DIFFICULT LARYNGOSCOPY BY ULTRASOUND GUIDED VALUATION OF ANTERIOR NECK SOFT TISSUE THICKNESS. Joti Kanoujiya , Abhay Sancheti and S. Swami. Resident, Department Of Anaesthesiology, Bharati Vidyapeeth University of Medical Science, Pune, India. Assistant Professor, Department of Anaesthesiology, Bharati Vidyapeeth University of Medical Science, Pune, India. Professor and HOD, Department of Anaesthesiology, Bharati Vidyapeeth University of Medical Science, Pune, India.

Preoperative difficult airway prediction using suprahyoid and infrahyoid ultrasonography derived measurements in anesthesiology.

Airway management is one of the most important skills in everyday practice of anesthesia. Improper airway managementmight contribute to significant morbidity and mortality. In some patients, clinical parameters do not anticipate all difficultiesrelated to airway management. Ultrasonography (US) might confer a potential screening tool for difficult airway. Suprahyoidand infrahyoid US measurements have been investigated for difficult airway prediction in anesthesiology. The most extensivelyinvestigated parameter was the anterior neck soft tissue thickness measured at different levels: anterior to the hyoid bone,epiglottis and vocal cords commissure. Hyomental distances measured with the head placed in neutral, sniffing or maximalhyperextended position and the derived hyomental distance ratios have also been evaluated for difficult airway prediction. Forthe evaluation of the tongue, measurements such as thickness, cross-sectional area, width, volume and tongue-to-oral cavityratio can be used. Thus, anesthesiologists have many available potential US measurements, which could provide informationregarding airway anatomy during the preoperative airway assessment and could serve as potential screening parameters fordifficult airway. Still, we do not yet know which of these provides optimal predictive accuracy and larger sample size studiesare required to validate their use in the preoperative evaluation of the airway.

Ultrasound measurement of anterior neck soft tissue and tongue thickness to predict difficult laryngoscopy - An observational analytical study.

Background and Aims:Airway ultrasound is an emerging tool to predict difficult laryngoscopy. This study aimed to determine the utility of ultrasound measurement of the anterior soft tissue neck thickness at the level of hyoid, thyrohyoid membrane and thickness of tongue to predict difficult laryngoscopy and compare them with clinical parameters for airway assessment.Methods:The distance from skin to hyoid bone, skin to the thyrohyoid membrane in neutral and sniffing position and maximum tongue thickness was measured by ultrasound and correlated with Cormack Lehane (CL) laryngoscope view in 310 adult surgical patients. Receiver operating characteristic curve was plotted and the area under the curve was calculated for each parameter. The sensitivity and specificity of ultrasound-guided parameters were compared with clinical parameters like the inter-incisor gap, modified Mallampatti classification, thyromental, sternomental distance and neck circumference.Results:Incidence of difficult laryngoscopy (CL grade-III and IV) was 11.3%. A significant difference was observed in the ultrasound parameters between the easy and difficult laryngoscopy (P-value = 0.001). Sensitivity and specificity to predict difficult airway was 69.6% and 77% for tongue thickness, 68% and 73% for the skin to hyoid bone distance in a neutral position and found to be higher than clinical parameters.Conclusion:The ultrasound measurements of soft tissue thickness of the anterior neck and tongue thickness along with the clinical assessment of airway can be useful in predicting difficult laryngoscopy.

An Evaluation of Ultrasound Measurements of Anterior Neck Soft Tissue and Other Predictors of Difficult Laryngoscopy in Morbidly Obese Patients

Objective: The aim of this study was to compare the ultrasonography (USG) measurements of anterior neck soft tissue and other clinical screening tests used to evaluate difficult laryngoscopy in morbidly obese patients. Materials and Methods: A total of 130 morbidly obese patients were scheduled for laparoscopic bariatric surgery. USG examination was performed of the vocal cords, thyroid isthmus, and suprasternal notch. Results: Analysis was made of 74 patients. Difficult laryngoscopy was considered as grade 3 or 4 on the Cormack and Lehane scale. In seven (9.5%) patients the classification was made of difficult laryngoscopy. The incidence of difficult laryngoscopy was significantly higher in patients with older age, hypertension, and obstructive sleep apnea syndrome. Grades of ≥5 on the intubation difficulty scale, which is a requirement for a styleted endotracheal tube and a high number of intubation attempts, were found to be significantly higher in the difficult laryngoscopy group. Sternomental distances for difficult and easy laryngoscopy were 11.5 ± 3.75 and 14.18 ± 2.63 cm, respectively. Conclusion: USG measurements of the anterior soft tissue thickness of the neck remain debatable for the prediction of difficult laryngoscopy in the literature. The results of this study demonstrated that USG measurements of anterior neck soft tissue have no advantage in the determination of difficult laryngoscopy in morbidly obese patients scheduled for bariatric surgery.

Airway changes following labor and delivery in preeclamptic parturients: a prospective case control study

BackgroundPreeclampsia is associated with greater narrowing of the airway than normal pregnancy, but it is not known if these changes worsen during labor and delivery. The aim of the study was to evaluate the airway during and after labor in women with or without preeclampsia. MethodsTwenty-five normal and 25 severely preeclamptic pregnant women in early labor were recruited in this single-center, prospective, case-control study. Airway assessment was performed (a) before active labor (b) within one hour of delivery and (c) 24–48 h postpartum. The Mallampati grade was the primary outcome. Sonographic measurements of tongue thickness, anterior neck soft tissue at the level of the hyoid bone and the vocal cords, thyromental distance, and neck circumference, were secondary outcomes. ResultsThe Mallampati score increased from the pre-labor to the post-labor period in both preeclamptic and normotensive patients (P=0.001 and P=0.002 respectively). A significant difference in tissue thickness at the hyoid level was observed between preeclamptic and normotensive patients pre-labor (P=0.035), post-labor (P=0.05) and postpartum (P=0.05). There was no significant difference in thyromental distance or neck circumference between groups at any time. The total duration of labor and a Mallampati change by one grade correlated (Spearman correlation coefficient 0.473). ConclusionAirway sonography may provide useful bedside anatomical information for prediction of difficult laryngoscopy. The change in airway dimensions and the Mallampati score during labor may persist for 48 h postpartum in both groups. Those with prolonged labor are more susceptible to changes in airway dimensions.

Ultrasonography - A viable tool for airway assessment.

Background and Aims:Accurate prediction of the Cormack-Lehane (CL) grade preoperatively can help in better airway management of the patient during induction of anaesthesia. Our aim was to determine the utility of ultrasonography in predicting CL grade.Methods:We studied 100 patients undergoing general endotracheal anaesthesia. Mallampati (MP) class, thyromental distance (TMD) and sternomental distance (SMD) were noted. Ultrasound measurements of the anterior neck soft tissue thickness at the level of the hyoid (ANS-Hyoid), anterior neck soft tissue thickness 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 of the distance between the vocal cords (E-VC) were obtained. CL grade was noted during intubation. Chi-square test was employed to determine if there was any statistical difference in the measurements of patients with different CL grades. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy were calculated for the various parameters.Results:The incidence of difficult intubation was 14%. An ANS-VC >0.23 cm had a sensitivity of 85.7% in predicting a CL Grade of 3 or 4, which was higher than that of MP class, TMD and SMD. However, the specificity, PPV and accuracy were lower than the physical parameters. The NPV was comparable.Conclusion:Ultrasound is a useful tool in airway assessment. ANS-VC >0.23 cm is a potential predictor of difficult intubation. ANS-Hyoid is not indicative of difficult intubation. The ratio Pre-E/E-VC has a low to moderate predictive value.

Value of ultrasound-measured quantification of anterior neck soft tissue in predicting difficult laryngoscopy in obese patients

Objective To evaluate the value of ultrasound-measured quantification of anterior neck soft tissue in predicting the difficult laryngoscopy in the obese patients. Methods Ninety-six patients, with body mass index ≥ 28 kg/m2, aged 22-60 yr, of ASA physical status Ⅰ or Ⅱ, scheduled for elective surgery under general anesthesia with endotracheal intubation, were selected.Assessment methods of modified Mallampati grade (method M) and anterior neck soft tissue quantification measured by ultrasound (method U) were performed before anesthesia.The level of vocal cords was selected using ultrasound scanning for anterior neck.The positive result was greater than 20 mm in method U, and was grade Ⅲ or Ⅳ in method M. Direct laryngoscope was placed after induction of anesthesia.Difficult laryngoscopy was defined as Cormack-Lehane grade Ⅲ or Ⅳ, or in whom laryngoscope could not be placed.The sensitivity, specificity and accuracy of the two assessment methods for predicting the difficult laryngoscopy were calculated. Results Twenty-two patients were found to have difficult laryngoscopy, and the anterior neck soft tissue quantification was (23.0±3.0) mm, which was significantly thicker than that in the patients of non-difficult laryngoscopy ((1.9±2.2) mm). The sensitivity, specificity and accuracy of method U were 91%, 92% and 92%, respectively, and of method M were 77%, 81% and 80%, respectively, and there was significant difference between the two methods.There was no significant difference in the parameters of difficult laryngoscopy which were predicted using method U between the patients of different ages or gender. Conclusion It can accurately predict the difficult laryngoscopy in the obese patients when the ultrasound-measured quantification of anterior neck soft tissue is greater than 20 mm. Key words: Skinfold thickness; Ultrasonography; Laryngoscopy; Obesity; Forecasting

Role of anterior neck soft tissue quantifications by ultrasound in predicting difficult laryngoscopy.

BackgroundThe aim of this study was to determine if ultrasound (US) measurements of anterior neck soft tissue thickness at hyoid bone (DSHB), thyrohyoid membrane (DSEM), and anterior commissure (DSAC) levels can be used to predict difficult laryngoscopy.Material/MethodsWe included 203 patients age 20–65 years scheduled to undergo general anesthesia in this prospective observational study. Correlation analysis and receiver operating characteristic curve (ROC) analysis were used to determine the roles of screening tests [interincisor gap (IIG), thyromental distance (TMD), modified Mallampati score (MMS)] and US measurements (DSHB, DSEM, DSAC) in predicting difficult laryngoscopy.ResultsThere were 28 out of 203 patients categorized as difficult laryngoscopy. DSHB, DSEM, DSAC, and MMS were greater in the difficult laryngoscopy group (P<0.0001). There was a strong positive correlation between DSEM and DSHB (r=0.74); moderate positive correlations between DSEM and DSAC (r=0.60), DSHB and DSAC (r=0.69); small positive correlations between MMS and DSHB (r=0.32), MMS and DSEM (r=0.27), MMS and DSAC (r=0.32), all P values ≤0.0001; very small positive correlation between TMD and IIG (r=0.18, P=0.0089); small negative correlation between IIG and MMS (r=−0.27, P=0.0001); and very small negative correlations between MMS and TMD (r=−0.20, P=0.004), IIG and DSAC (r=−0.18, P=0.011), IIG and DSHB (r=−0.15, P=0.034). The areas under the ROC curve (AUCs) of MMS, DSHB, DSEM, and DSAC were significantly larger compared with the reference line (P<0.0001).ConclusionsAnterior neck soft tissue thicknesses measured by US at hyoid bone, thyrohyoid membrane, and anterior commissure levels are independent predictors of difficult laryngoscopy. Combinations of those screening tests or risk factors with US measurements might increase the ability to predict difficult laryngoscopy.

156 Utility of Bedside Ultrasound as Airway Assessment Tool in Patients Receiving Procedural Sedation

156 Utility of Bedside Ultrasound as Airway Assessment Tool in Patients Receiving Procedural Sedation

Pilot Study to Determine the Utility of Point‐of‐care Ultrasound in the Assessment of Difficult Laryngoscopy

Prediction of difficult laryngoscopy in emergency care settings is challenging. The preintubation clinical screening tests may not be applied in a large number of emergency intubations due to the patient's clinical condition. The objectives of this study were 1) to determine the utility of sonographic measurements of thickness of the tongue, anterior neck soft tissue at the level of the hyoid bone, and thyrohyoid membrane in distinguishing difficult and easy laryngoscopies and 2) to examine the association between sonographic measurements (thickness of tongue and anterior neck soft tissue) and difficult airway clinical screening tests (modified Mallampati score, thyromental distance, and interincisor gap). This was a prospective observational study at an academic medical center. Adult patients undergoing endotracheal intubation for an elective surgical procedure were included. The investigators involved in data collection were blinded to each other's assessments. Demographic variables were collected preoperatively. The clinical screening tests to predict a difficult airway were performed. The ultrasound (US) measurements of tongue and anterior neck soft tissue were obtained. The laryngoscopic view was graded using Cormack and Lehane classification by anesthesia providers on the day of surgery. To allow for comparisons between difficult airway and easy airway groups, a two-sided Student's t-test and Fisher's exact test were employed as appropriate. Spearman's rank correlation coefficients were used to examine the association between screening tests and sonographic measurements. The mean (±standard deviation [SD]) age of 51 eligible patients (32 female, 19 male) was 53.1 (±13.2) years. Six of the 51 patients (12%, 95% confidence interval [CI] = 3% to 20%) were classified as having difficult laryngoscopy by anesthesia providers. The distribution of laryngoscopy grades for all subjects was 63, 25, 4, and 8% for grades 1, 2, 3, and 4, respectively. In this study, 83% of subjects with difficult airways were males. No other significant differences were noted in the demographic variables and difficult airway clinical screening tests between the two groups. The sonographic measurements of anterior neck soft tissue were greater in the difficult laryngoscopy group compared to the easy laryngoscopy group at the level of the hyoid bone (1.69, 95% CI = 1.19 to 2.19 vs. 1.37, 95% CI = 1.27 to 1.46) and thyrohyoid membrane (3.47, 95% CI = 2.88 to 4.07 vs. 2.37, 95% CI = 2.29 to 2.44). No significant correlation was found between sonographic measurements and clinical screening tests. This pilot study demonstrated that sonographic measurements of anterior neck soft tissue thickness at the level of hyoid bone and thyrohyoid membrane can be used to distinguish difficult and easy laryngoscopies. Clinical screening tests did not correlate with US measurements, and US was able to detect difficult laryngoscopy, indicating the limitations of the conventional screening tests for predicting difficult laryngoscopy.

230: Feasibility of Performing Bedside Ultrasonography to Assess a Difficult Airway

230: Feasibility of Performing Bedside Ultrasonography to Assess a Difficult Airway

Prediction of difficult laryngoscopy in obese patients by ultrasound quantification of anterior neck soft tissue.

In 50 morbidly obese patients, we quantified the soft tissue of the neck from the skin to the anterior aspect of the trachea at the vocal cords using ultrasound. Thyromental distance, mouth opening, limited neck mobility, modified Mallampati score, abnormal upper teeth, neck circumference and sleep apnoea were assessed as predictors of difficult laryngoscopy. Of the nine (18%) cases of difficult laryngoscopy, seven (78%) had a history of obstructive sleep apnoea, compared with two of the 41 patients (5%) in whom laryngoscopy was easy (p < 0.001). Patients in whom laryngoscopy was difficult had more pretracheal soft tissue (mean (SD) 28 (2.7) mm vs. 17.5 (1.8) mm; p < 0.001) and a greater neck circumference (50 (3.8) vs. 43.5 (2.2) cm; p < 0.001). None of the other predictors correlated with difficult laryngoscopy. We conclude that an abundance of pretracheal soft tissue at the level of the vocal cords is a good predictor of difficult laryngoscopy in obese patients.

What Constitutes A 'Thorough' Autopsy in Unexpected Infant Death?

□ 79 Although the Beckwith definition specified that a 'thorough' autopsy was required before a death could be attributed to SIDS, and despite the prevalence of numerous recent autopsy protocols, consensus is lacking as to what constitutes an acceptable postmortem examination in cases of unexpected infant death. In fact, it is well known that the term 'SIDS' is being used in cases where autopsies are not being performed, and the possibility of limited, or even 'verbal' autopsies has recently been discussed. Part of the difficulty in the examination of these cases has resulted from the somewhat artificial separation of the disciplines of pediatric from forensic pathology. However, unless consensus can be reached regarding the appropriate pathological investigation of these infants, comparisons of data among centers will be seriously flawed, and individual cases will be diagnosed without application of consistent criteria. The following additional steps to supplement the routine examination are proposed to engender discussion as to what is required to adequately investigate the unexpected death of an infant or young child by excluding occult trauma: External examination to include otoscopic examination of the nares, nasal septum and ear canals for trauma; specific examination for the presence or absence of retroauricular petechiae; and genital and anal examination with swabs, scrapings and material for DNA if required. Radiological examination to consist of a full skeletal survey with directed views of metaphyses and posterior ribs. Internal examination to include anterior neck, chest, abdomen, buttock, posterior neck and back soft tissue dissection to exclude deep bruising. Toxicological examination to exclude potentially lethal levels of prescription and nonprescription drugs. Removal and examination of the eyes and and at least the cervical and upper thoracic spinal cord to be undertaken if any significant injury is detected, if there is cerebral oedema and hemorrhage, if there are concerns from the death scene examination or clinical/family history review. Undertaking such extra activities may result in positive findings which would prevent the term 'SIDS' from being used e.g. skin petechiae indicating accidental or inflicted asphyxia, or bruises or fractures indicating inflicted injury.