Accuracy of airway ultrasound parameters to predict difficult airway using the LEMON criteria as a reference: A cross-sectional diagnostic accuracy study.

OBJECTIVES: Ultrasound (US) airway indexes were frequently compared with other scoring systems such as Mallampati score and Cormack - Lehane classification system, but to the best of our knowledge never with LEMON. Here, in this study, we evaluated the accuracy of some recommended airway US parameters in terms of screening difficult airway using the LEMON criteria as a reference. METHODS: This was a cross-sectional diagnostic accuracy study in which people with at least 18 years old coming to the emergency departments for any reason who had consent for participation, were enrolled with the simple random sampling method. Hyo-mental distance (HMD), skin to epiglottis distance (EP), and peri-epiglottic space to epiglottis to vocal cord ratio (PEP/E. VC) were the US indexes that were calculated in all participants. Using a preprepared checklist, measured US parameters were recorded. For each participant, the LEMON score variables were also assessed and recorded, and the cutoff point for considering as a difficult airway case, based on LEMON score, was 2. Demographic characteristics of the participants were also registered. RESULTS: A total of 299 cases with a mean age of 41.1 years (95% confidence interval [CI]: 39.3-42.9), were participated. Based on LEMON score ≥2, 20 participants (6.7%) were categorized in difficult airway group. Comparison of the PEP/E. VC (P = 0.007) and EP distance (P = 0.049) of the participants based on LEMON score showed a statistically significant difference; but comparison of the means of HMD in the two groups was not statistically significant (P = 0.144). The median of EP of the participants was 7.70 mm (interquartile range [IQR]: 6.70-9.40). The best cutoff point of EP distance for evaluating a difficult airway was 12.27 mm and more with the sensitivity of 35% and the specificity of 86.96% (accuracy = 0.614; 95% CI: 0.492-0.736). The median of PEP/E. VC was 1.01(IQR: 0.79-1.23). The best cutoff point of PEP/E. VC for evaluating a difficult airway was 0.88 and less with the sensitivity of 70% and the specificity of 67.38% (accuracy = 0.701; 95% CI: 0.583-0.818). CONCLUSION: As per our results, PEP/E. VC and EP distance measured with sonography can be used in distinguishing the difficult airway, using the LEMON criteria as the reference. However, further studies are needed to use PEP/E. VC and EP distance as a part of reliable indexes.

Value of Canadian C-spine rule versus the NEXUS criteria in ruling out clinically important cervical spine injuries: derivation of modified Canadian C-spine rule.

PURPOSE: Although, Canadian C-spine rule and the National Emergency X-Radiography Utilization Study (NEXUS) criteria in ruling out clinically important cervical spine injuries have been validated using large prospective studies, no consensus exist as to which rule should be endorsed. Therefore, the aim of the present study was to compare the accuracy of the Canadian C-spine and NEXUS criteria in ruling out clinically important cervical spine injuries in trauma patients. Finally, we introduced the modified Canadian C-spine rule. METHODS: A prospective diagnostic accuracy study was conducted on trauma patients referred to four emergency departments of Iran in 2018. Emergency physicians evaluated the patients based on the Canadian C-spine rule and NEXUS criteria in two groups of low risk and high risk for clinically important cervical spine injury. Afterward, all patients underwent cervical imaging. In addition, modified Canadian C-spine rule was derived by removing dangerous mechanism and simple rear-end motor vehicle collision from the model. RESULTS: Data from 673 patients were included. The area under the curve of the NEXUS criteria, Canadian C-spine, and modified Canadian C-spine rule were 0.76 [95% confidence interval (CI) 0.71-0.81)], 0.78 (95% CI 0.74-0.83), and 0.79 (95% CI 0.74-0.83), respectively. The sensitivities of NEXUS criteria, Canadian C-spine, and modified Canadian C-spine rule were 93.4%, 100.0% and 100.0%, respectively. CONCLUSIONS: The modified Canadian C-spine rule has fewer variables than the original Canadian C-spine rule and is entirely based on physical examination, which seems easier to use in emergency departments.

Three-component Synthesis of Novel Highly Functionalized 2,6-dihydropyrimido[2,1-a]isoindole Derivatives.

Three-component reaction of dialkyl acetylenedicarboxylates, isocyanides and 1,3- diimino isoindoline affords highly functionalized 2,6-dihydropyrimido[2,1-a]isoindole derivatives in good yields under catalyst free and mild reaction conditions.