Comparative study between Modified William's Airway (Fekry Airway ) versus the U Shaped Guedl's Airway as assisted device for fiber optic intubation: A Randomized controlled trial.

: Background : In the last few years fiber optic bronchoscope (FOB) played a major role in management of difficult airway . Usage of oropharyngeal airways allow easy visualization of vocal cords by fiber optic bronchoscope . Methods : Fifty patients undergoing elective surgeries under general anesthesia were enrolled in this study. Intubation was done using the fiber optic bronchoscope assisted by one of the airways. The patients were classified into 2 groups: G w (n=25) intubation assessed by modified William's airway and G U (n=25) ) intubation assessed by U shaped Guedl's airway . Results : The bronchoscopic view was better in modified William's airway than U shaped Guedl's airway ( grade 1 was in 44% , 36% of patients ) respectively. Time to reach vocal cords was (5 ±0.84 s , 6.2 ± 0.90 s ) and the total time of intubation was ( 17.6 ± 1.8 s ,20.7± 1.5s ) both were shorter in Modified William's airway than U shaped Guedl's airway respectively and both were statistically significant. recorded from both airways was minimal . Conclusion : We conclude that both William's U shaped good William's airway show better time to reach the VC , total intubation time and need less manipulation to allow tube insertion .Further studies needed to assess the efficacy of these devices in difficult intubation patients


Declaration of interests
The authors declare that they have no conflict of interest with this work.
Comparative study between Modified William's Airway (Fekry Airway ) versus the U Shaped Guedl's Airway as

Introduction:
In the last few years fiber optic bronchoscope (FOB) took the upper hand in difficult airway management . Several oropharyngeal airways and supraglotic devices have been invented to facilitate the art of fiber optic intubation. [1] These devices allow minimal manipulation through upper airway till reaching the vocal cords, and reducing the total intubation time .
In the clinical market there are several oropharyngeal airways used to facilitate FOB intubation like: Ovassapian, Wiliams, Berman, LMA MADgic, modified Guedel's and modified William's airways [2] .In this study we discussed two types of these airway with some modifications , the Modified William's Airway and the modified Guedels Airway ( U shaped Guedel's Airway) .
The modification made to the William's airway (Fekry's airway) was removal of the proximal cylindrical tunnel roof and opening of its concave part to allow one step insertion of the tube. There is no need to disconnect the tube connector after tube insertion to remove the airway. [3] ( Figure 1). Patients were randomly allocated into 2 equal groups 25 each using random computer allocation with numbered closed opaque envelopes :  G w (n=25 ) the fiber optic intubation was done through Modified William's airway .
 G u (n=25) the fiber optic intubation was done through U shaped Guedel's airway .
In the pre-operative preparation room, 20 gauge cannula was inserted in a Adequate ventilation was confirmed by chest expansion ,bilateral equal air entry using stethoscope and the appearance 6 successive capnographic waves.
During any step of endotracheal intubation if SPO2 dropped to ≤ 93% the trial was aborted and the patient was ventilated again using mask -bag until SPO 2 increase to 100% ). After removal of the airway ; blood stained mucous was noticed over the airway and recorded as complication. After full recovery a questionnaire for sore throat was done for the patient by a blind investigator who didn't know which airway used.

Sample size
Our primary outcome was the total intubation time .  5 (Chan, 2003b). P-values less than 0.05 were considered as statistically significant.

Results:
Seventy-five patients were screened for eligibility. twenty-five were excluded due to refusal and did not meet the inclusion criteria , fifty patients underwent randomization and were available for final analysis.
( Figure 3) The bronchoscopic view grades results showed that, there was no statistical significant difference in the view grades between both devices ( p = 0.702) . (Table 3).

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Regarding The time to reach the VC by fiberoptic bronchoscope was shorter in G W than in G U ( 4.96 ±0.84 S , 6.16 ±0.90 S) respectively and that was statistically significant (p = 0.001) . (Table 3) . (Figure 4).
The total intubation time was shorter in G W than in G U respectively and that was statistically significant (p = 0.001). (Table 3) ( Figure 5) The complications recorded during usage of both airways was minimal and statistically non-significant. (Table 4)

Discussion :
The usage of different oropharyngeal airway as a conduit for fiberoptic endo tracheal intubation had many benefits to the anasethiologist such as easy and rapid visualization of the vocal cords to facilitate endotracheal intubation .
In this study we compared two airways with modification In their original shape to allow easy fiber optic endo tracheal intubation. Regarding The time to reach VC by FOB was 5 ± 0.8 s in G W and was 6.1±0.9 s in G U .These results were similar to K.E Greenland [6] comparing William's airway versus Breman airway in G W which was 4 (1-16) seconds median (range) and in contrast to our study , another study by K.E Greenland [5]  On recording complications, the G U showed more hoarseness of voice than G W . we refer that to more manipulation done during insertion of the tube to get the view. The blood over the device detected only in G U group.

Limitations:
The limitation of this study is that blindness was impossible for the investigator .

Conclusion :
We conclude that both Modified William's and U shaped Guedl's airway