Incidence and main risk factors of anticipated and unanticipated fiberoptic intubation

Introduction or objective: Airway management is the cornerstone
of anesthesia. Awake Fiberoptic intubation (FI) is used most commonly for anticipated cases. However, in unanticipated difficult
airway cases, FI might be the solution if bag-mask ventilation is
possible. Aim of the study: To estimate the incidence and main risk
factors for unanticipated fiberoptic intubation (FI).
Material and methods: We conducted retrospective case-controlled
study, selecting cases where Fiberoptic intubation (FI) was used
under general anesthesia (GA) in period from 2018–2021, in Riga,
Latvia. We analyzed demographical data, type of surgery, predictive
signs of difficult intubation, and consequently the use of FI, as well
as association of FI and emergency incidents. All cases were divided
into two groups: Difficult airways (DA) were anticipated and awake
FI was performed (N=102) or DA was unanticipated and FI was performed after induction of GA (n=33). Data were analyzed using IBM
Statistical Package of Social Sciences (SPSS).
Results: We identified 135 FI patients out of 50,186 general anaesthesia cases in Riga East University Hospital. Mean age was 60.38±14.17
years, males 75 (55.6%), body mass index (BMI) 28.9±6.4 kg/m2. The
incidence of FI were 6.7 cases on every 10,000 GA annually. From 135
cases requiring FI, 33 (24.4%) were unanticipated, demonstrating the
incidence of 1.63 cases on every 10,000 GA. In group of unanticipated
FI, the mean age was 61±14.5 years. In unanticipated group, there
were 21 males vs 12 females. BMI 27.4±5.8 vs anticipated mean BMI
29.4±6.5. The most common predictive factors when FI was used were
tracheal stenosis and dislocation 67 (49.6%), small mouth opening
(between emergency and elective cases. The relation between these
variables was significant, 2 (2, N=135) = 14.5, pcases were more likely to occur in unanticipated group. Also significant association was found in Mallampati group, concluding that the
higher Mallampati score, more likely they were in anticipated group
2 (4, N=135) = 10.5, p=0.035. During airway management 24.4% of
patients – all in unanticipated group experienced SpO2 two patients’ had significant desaturation with SpO2 of 43% and 54%.
However, we did not identify any long term major complications in
both groups.
Discussion and conclusion: Main risk factors for anticipated and
unanticipated FI showed that in case of obvious risk factors for difficult intubation, like previously known tracheal pathologies, small
mouth opening, and higher Mallampati score, awake FI was the
method of choice. However in unanticipated group, risk factors for
DA were less likely to be identified and more often FI occured in the
emergency cases.