Application Of S-shaped Laryngoscopes And S-shaped Video Laryngoscopes In Patients With Endotracheal Intubation

Objective:To compare application effect of Macintosh and S-shaped laryngoscopes in patients with predicted difficult intubation.To compare application effect of S-shaped video laryngoscopes and UE Video laryngoscopes in patients with endotracheal intubation.Methods:The clinical trial was divided to two parts: one contrast test for Macintosh laryngoscopes and S-shaped laryngoscopes in patients with predicted difficult intubation.Another is for S-shaped video laryngoscopes and Video laryngoscopes in patients with endotracheal intubation.Part1: 57 cases of patients under general anesthesia undergoing selective operation,ASA?-?grade,aged 18-65 years old,BMI 18-30,masticatory movement>3cm,Thyromental distance<6cm,Mallampati grade ?-?,were randomly divided into the Macintosh laryngoscope group(M,28cases)and the S-shaped laryngoscope group(S,29cases).the measurements of the masticatory movement,thyromental distance,bilateral mandiublar midpoint distance were performed before induction of anesthesia,After induction of anesthesia,the S-shaped laryngoscope was used to expose the glottis in the group M.the Cormack-Lehane grade and the Cormack-Lehane grade when the laryngeal pressured were observed and recorded.The time of exposing glottis were recorded.the value of mean arterial pressure(MAP)and heart rate(HR)at different time of before anesthesia induction,After anesthesia induction and exposing glottis were recorded.the Macintosh laryngoscope was secondly used to expose the glottis and intubation.the Cormack-Lehane grade and the Cormack-Lehane grade of optimal external laryngeal pressure were observed and recorded when exposing glottis.the time of exposing glottis and the number of intubation,the case which laryngeal was pressured for intubation were recorded.the success rate of one-time intubation and intubation complication related cases were recorded.In the group S,the Macintosh laryngoscope was used to expose the glottis and secondly used S-shaped laryngoscope to expose glottis and intubate.the same parameters as the group M were recorded.Result:Two laryngoscopes were used in 57 patients,the C/L grade used S-shaped laryngoscope were better than used the Macintosh laryngoscope with statistical difference(p=0.000,<0.05).The C/L grade of pressuring Cricoid cartilage to assist was better in S-shaped laryngoscope than those in Macintosh laryngoscope(p=0.000,< 0.05)with statistical difference.The time of exposing glottis had no statistical difference between the used Macintosh laryngoscope and S-shaped laryngoscope(p=0.300,>0.05).The MAP and HR at different time points had no statistical differences between the group M and group S(p>0.05).The time of intubation in the group S were less than in the group M with statistical difference(p=0.030,<0.05).the case of press cricoid cartilage for intubation in the group S was less than in the group M(p=0.008<0.05).the success rate of intubation had no statistical differences between the group M and group S(p=0.050).there was not statistical difference in intubation complication between the two groups(p=0.079,>0.05).An empirical analysis found no correlation between C/L grade and bilateral mandiublar midpoint distance(p=0.621,p=0.188,>0.05).There were negative correlation between C/L grade and the thyromental distance in used Macintosh laryngoscope and pressured cricoid cartilage(p=0.002,p=0.02,<0.05).There was a negative correlation between C/L grade and both the product of the mental distance and the bilateral mandibular midpoint distance in used Macintosh laryngoscope and S-shaped laryngoscope(p=0.009,p=0.034,<0.05).Part2: 120 cases of patients undergoing selective operation under general anesthesia,ASA?-?grade,aged 18-65 years old,BMI 18-26,masticatory movement>3cm,Thyromental distance>6cm,Mallampati grade?-? were randomly divided into the S-shaped video laryngoscope group(A,60cases),and the UE video laryngoscope group(B,60cases).In the group A,S-shaped video laryngoscope was used to expose the glottis and intubation after induction of anesthesia.However,UE video laryngoscope was used in the group B.The Cormack-Lehane grade,the time of exposing glottis and the number of intubation were recorded.The success rate of intubation and the cases with intubation complication were recorded.The value of mean arterial pressure(MAP)and heart rate(HR)at different time(before anesthesia induction,after anesthesia induction and exposing glottis)were recorded.Result : The Cormack-Lehane grade,the time of exposing glottis and the time of intubation had no statistical differences between the group A and group B(p=0.355,p=0.417,p=0.232,p=1.000>0.05).There was no statistical difference in the success rate of disposable intubation between the group A and group B(p>0.05).The MAP and HR at different time points had no statistical differences between the group A and group B(p>0.05).The intubation complication in group A was less than that in group B(p=0.031,<0.05).Conclusion : The S-shaped laryngoscope in patients with predicted difficult intubation is better than Macintosh laryngoscope.in glottis exposure effect,improving the success rate of intubation and reducing complication of intubation.the S-shaped video laryngoscope has fewer intubation complication than UE video laryngoscope.There were a negative correlation between C/L grade and both the product of the mental distance and the bilateral mandibular midpoint distance,which has certain guiding significance in assessment of glottis exposure during laryngoscope operation.