Background: Ultrasonography-assessed hyomental distance (HMD) ratio has been found to discriminate between obese patients with Cormack-Lehane grades 1 or 2 vs. those with grades 3 or 4. The aim of our study is to evaluate the performance of the HMD evaluated ultrasonographically in neutral, ramped, and maximum hyperextended positions, as well as for the ratios obtained by dividing the HMD in the ramped position to that in the neutral position (HMDR1) and by dividing the HMD in maximum hyperextension to that in the neutral position (HMDR2), in order to predict the occurrence of Cormack-Lehane grades 3 or 4 during direct laryngoscopy. Methods: Ultrasound measurements were performed preoperatively in 25 patients with morbid obesity, measuring the HMD in the neutral, ramped, and maximum hyperextended positions. Pre-epyglotic soft tissue thickness, Mallampati and upper lip bite test scores were recorded. Cormack-Lehane grading was considered as an outcome variable in the Receiver Operating Characteristics curve analysis. Results: HMD in the neutral, ramped and maximum hyperextended positions presented similar sensitivities, 100% [39.8-100.0]. For HMD, specificity was 42.86% [21.8-66.0] in the neutral position, 61.9% [38.4-81.9] in the ramped postion, and 71. 4% [47.8-88.7] in the maximum hyperextended position. For HMDR1, the cut-off value was 1.12. This threshold provides 75% [19.4-99.4] sensitivity and 76. 2% [52.8-91.8] specificity. For HMDR2, a cut-off value of 1.23 provides 100% [39.8-100.0] sensitivity and 90.5% [69.6-98.8] specificity. Conclusion: HMDR2 seems to have superior diagnostic accuracy in predicting difficult laryngoscopy in the obese population compared to HMDR1, as well as compared to the HMD in the neutral, ramped, and maximum hyperextended positions.

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Purpose: To describe the correlation between clinically measured hyomental distance ratio (HMDR clin ) and the ultrasound measurement (HMDR echo ) in patients with and without morbid obesity and to compare their diagnostic accuracy for difficult airway prediction. Methods: HMDR clin and HMDR echo were recorded the day before surgery in 160 consecutive consenting patients. Laryngoscopy was performed by a skilled anesthesiologist, with grades III and IV Cormack-Lehane being considered difficult views of the glottis. Linear regression was used to assess the correlation between HMDR clin and HDMR echo and receiver operating curve analysis was used to compare the performance of the two for predicting difficult airway. Results: The linear correlation between HMDR clin and HDMR echo in patients without morbid obesity had a Pearson coefficient of 0.494, while for patients with morbid obesity this was 0.14. A slightly higher area under the curve for HMDR echo was oberved: 0.64 (5%CI 0.56-0.71) versus 0.52 (95%CI, 0.44-0.60) (p = 0.34). Conclusion: The association between HMDR clin and HDMR echo is moderate in patients without morbid obesity, but negligible in morbidly obese patients. These might be explained by difficulties in palpating anatomical structures of the airway.

Understanding of how the human organism functions has preoccupied researchers in medicine for a very long time. While most of the mechanisms are well understood and detailed thoroughly, medicine has yet much to discover. Iron (Fe), Copper (Cu), and Zinc (Zn) are elements on which organisms, ranging from simple bacteria all the way to complex ones such as mammals, rely on these divalent ions. Compounded by the continuously evolving biotechnologies, these ions are still relevant today. This review article aims at recapping the mechanisms involved in Fe, Cu, and Zn homeostasis. By applying the knowledge and expanding on future research areas, this article aims to shine new light of existing illness. Thanks to the expanding field of nanotechnology, genetic disorders such as hemochromatosis and thalassemia can be managed today. Nanoparticles (NPs) improve delivery of ions and confer targeting capabilities, with the potential for use in treatment and diagnosis. Iron deficiency, cancer, and sepsis are persisting major issues. While targeted delivery using Fe NPs can be used as food fortifiers, chemotherapeutic agents against cancer cells and microbes have been developed using both Fe and Cu NPs. A fast and accurate means of diagnosis is a major impacting factor on outcome of patients, especially when critically ill. Good quality imaging and bed side diagnostic tools are possible using NPs, which may positively impact outcome.