Assessment of Airway Changes During Pregnancy With Ultrasonography and Clinical Airway Screening Tests: A Prospective Observational Study

INTRODUCTION: Ultrasonographic airway assessment is a promising adjunct to predict difficult intubation; however, it has been relatively less studied in obstetric cases. This study aimed to assess the progress of anatomical changes in the obstetric airway, through all the three trimesters, using ultrasound measurements and clinical screening methods. MATERIALS AND METHODS: This prospective observational study included 205 women with singleton pregnancies. In clinical assessment, modified Mallampati class and neck circumference were noted. In ultrasonographic assessment, the skin-to-epiglottis distance and tongue volume were measured. In every study participant, the measurements were recorded three times, once in each of the three trimesters. The primary objective was to assess and compare the clinical and ultrasonographic airway changes during the three trimesters of pregnancy. Secondary objectives were to assess airway changes among those with pre-eclampsia and to assess clinical parameters, such as history of snoring, change of voice, and presence of facial oedema throughout the pregnancy. RESULTS: There was an increase in the modified Mallampati grade (p = 0.0001), neck circumference (mean difference = -0.40, p = 0.0001), skin to epiglottis distance (mean difference = -0.82, p = 0.0001), and tongue volume (mean difference = -0.84, p = 0.0001), especially during the third trimester. CONCLUSION: During the course of normal pregnancy, the skin-to-epiglottis distance and tongue volume increased progressively through the trimesters, reflecting the changes in the Mallampati scores and neck circumference. These findings could help in the prediction and management of the difficult airway during various stages of pregnancy.