Incidence of difficult intubation in thyroid gland surgery

Background: Difficult intubation (DI) occurs in 1% to 3% in general population, and unsuccessful intubation in 0.04%. DI may cause a lot of undesirable effects during prolonged intubation period, including lethal outcome. The aim of the study was to establish the incidence of DI in thyroid gland surgery and to compare the incidence of DI to predicted DI due to different DI screening testes. Methods: Prospective study included 2000 patients, which underwent thyroid gland surgery in Center for endocrine gland surgery, Clinical Center of Serbia, Belgrade, during 1999-2001. 436 of them were thyroid carcinomas 525 were nodal goiter, 671 polynodal goiter and 368 hyperthyreosis; 1705 female, 295 men, average age 48.1 year. According to ASA classification (American Society of Anesthesiologist's classification for correlation between co-existing diseases and perioperative complications) there were 886 ASA I, 901 ASA II and 213 ASA III. We used Mallampathi classes, Wilson criteria and Cormack-Lehane (CL) criteria to predict DI, and CL criteria to define DI. The complications during DI were analyzed and the ratio of DI to predicted DI was established. Results: There were 110 DI- 84 women, 26 men. Considering diagnosis there were T 24, PS 42 H 22. ASA III were 9.38%, ASAII 5.77, ASAI 4.28%. There were 3 unsuccessful intubations. Complications during DI were noted in 32 patients. Ratio between expected DI and DI, and unexpected DI and DI were: 12.77% failed positive and 0.45% failed negative results. Conclusion: Incidence of DI in thyroid gland surgery is twice more in men than in women. Screening tests for prediction DI showed higher specify than sensitivity.