Relationship between head-neck area measurements and scoring systems in determining difficult intubation in caesarea operations

Objective: The likelihood of difficult intubation is higher in pregnant women compared to the general population. Identifying patients who are likely to experience difficult intubation enables necessary interventions and is essential for patient safety. There is no definitive consensus on the effectiveness of evaluation tests. Studies have shown that combining multiple tests can provide more accurate predictions. The aim of our study is to evaluate the reliability of preoperative airway assessment tests in identifying difficult airways in obstetric patients. Methods: In our study, data were collected to determine the likelihood of difficult intubation in elective and emergency cesarean cases conducted between 23.08.2023 and 23.08.2024 at the Akdeniz University Faculty of Medicine Hospital. The data were prospectively and observationally recorded. We included patients aged 18 and older scheduled for emergency or elective cesarean sections, with general or regional anesthesia planned. Patients were informed about the evaluations. In this study, measurements and observational evaluations that assist in identifying difficult intubation (included in the study form) were performed for all cesarean cases and recorded in the study form. Mallampati classification, Cormack-Lehane classification, Wilson risk classification, thyromental distance (Patill sign), sternomental distance, interincisor gap, and mouth opening measurements were recorded and evaluated. The data were analyzed using IBM SPSS Statistics 18 © Copyright SPSS Inc. 1989, 2010 software. The variables in the study are presented as mean ± standard deviation (SD). Pearson Chi-square test was used for the analysis of categorical variables, and measurement values were compared using the T-test. A statistical significance level of 0.05 was accepted. Results: In our study, 546 patients who underwent cesarean surgery were evaluated for difficult intubation criteria. In this evaluation, BMI and Mallampati score were considered. Other difficult intubation evaluation methods in our study were statistically compared with Mallampati and BMI. Among the patients undergoing cesarean surgery, 229 (41.94%) ASA II and III patients received general anesthesia, and 317 (58.05%) received spinal anesthesia. Of the 147 obese patients with a high BMI, 105 (71.4%) had a normal Mallampati score, and 42 (28.6%) had a high Mallampati score. In the group with a high BMI, the likelihood of difficult intubation according to Mallampati was statistically significantly higher (p=0.0001, p<0,05). In our study, 229 patients underwent general anesthesia. Among these patients, 23 patients (n=23) with a Cormack-Lehane score of "3," 18 (78.3%) had a difficult Mallampati score, and 5 (21.7%) had a normal Mallampati score. This difference was statistically significant (p=0.0001, p<0,05). In patients with reduced mouth opening, the likelihood of difficult intubation in Mallampati assessment was also higher, and this evaluation was found to be statistically significant (p=0.0001, p<0,05). In patients with restricted head extension (n=88), 80.7% had a normal Mallampati score, while 19.3% showed a higher risk for difficult intubation. In our study, patients with restricted neck movements had a higher Mallampati score, and this was statistically significant (p=0.0001, p<0,05). Among 213 patients with a neck circumference of 40 cm or more, 37 had a Mallampati score indicating difficult intubation, and these values were considered statistically significant in our study (p=0.0001, p<0,05). Only 2% of patients with a normal thyromental distance had a Mallampati score indicating difficult intubation. Among 294 patients with a short thyromental distance, 39 showed a Mallampati score indicating difficult intubation, and this difference was statistically significant (p=0.0001, p<0,05). Sternomental distance, similar to thyromental distance, was statistically significant when compared with Mallampati in identifying difficult intubation. Of the 23 patients considered to have difficult intubation according to the Cormack-Lehane classification, 20 (87.0%) had a high BMI, and this difference was statistically significant (p=0.0001, p<0,05). Among 88 patients with normal head extension, 35 (39.8%) had a high BMI, while 53 patients (60.2%) had a normal BMI. The relationship between BMI and head extension was statistically significant (p=0.003, p<0,05). Among the 213 patients with thick neck circumferences, 121 (56.8%) were classified as overweight or obese, and this difference was statistically significant (p=0.0001, p<0,05). Among 294 patients with reduced thyromental distance, the proportion of patients with a high BMI was higher (31.3%, n=92), and this change was statistically significant (p=0.013, p<0,05). Among 226 patients with a short sternomental distance (12 cm or less), 107 (47.3%) had a high BMI, and these differences were also statistically significant (p=0.001, p<0,05). No statistically significant difference was found between Lemon, Boots, and Moans difficult intubation scores and BMI or Mallampati (p>0.05). Conclusion: Our study concluded that BMI and Mallampati are strong predictors of difficult intubation. We showed that combining these evaluations with Cormack-Lehane, thyromental distance, sternomental distance, and neck circumference allows for more accurate predictions in identifying difficult intubation. Keywords: Caesarean, Mallampati, Body Mass Index.