Dimensional Changes of Trachea in Second and Third Trimester Fetuses –an Anatomical Study

Introduction: Advances in neonatal medicine have led to the early diagnosis and treatment of respiratory diseases, and the recent development of fetal airway surgery. Data on the growth of the trachea and bronchi are not readily available to the anesthesiologist and bronchoscopist in spite of the obvious clinical interest. The aim of this study was to determine the anatomical development of tracheal structures during the fetal periods and to correlate these observations with other fetal biometric parameters to estimate developmental particularities of the fetal airway. Materials and methods: The study was carried out in the department of Anatomy, on 28 human fetuses of known gestational age (GA) from spontaneous abortions or stillbirths, aged 16–37 weeks of gestation which were categorized into second and third ( trimesters. Following parameters were noted prebifurcation length (PL), birfurcation length (BL), bifurcation-to-prebifurcation length ratio (BL/PL), Upper external transverse diameter (UD), Lower external transverse diameter (LD), Circumference (C) of trachea at the level of last tracheal cartilage. Results: The mean and standard deviations were calculated for second and third trimester and values were compared using student t-test. There was significant difference in means for PL, UD and LD between second and third trimesters. The various parameters were correlated with GA using Pearson’s correlation test. SPSS version 16 was used for the statistical analysis. No significant correlation was found for LD (r=0.2, p=0.2) and for C (r=0.19, p=0.3). Conclusion: Authors conclude that the tracheal length increases significantly proportional to the GA, but not the diameter.