The Clinical Research Of Ultrasound In Predicting Difficult Airway In Patients With OSAHS

Background and ObjectiveObstructive sleep apnea hypopnea syndrome(OSAHS)is an increasingly common disease in which upper respiratory tract collapse occurs repeatedly during sleep,leading to decreased oxygen saturation and awakening of sleep.The long-term presence of OSAHS can cause damage to multiple systemic organs throughout the body,including cognitive impairment,hypertension,coronary heart disease,and gastroesophageal reflux disease.It is mainly characterized by daytime sleepiness,inattention,memory loss,etc,which seriously affect patients's daily life.In addition,with the increased awareness of the diagnosis of OSAHS,a number of additional OSAHS-related diseases have been reported in recent years,including chronic kidney disease,erectile dysfunction,eye disease,Alzheimer's disease,nocturia,and even cancer.It will manifest as nighttime enuresis and bruxism,which will seriously reduce the quality of life and can be partially reversed by active treatment.Uvulopalatopharyngoplasty(UPPP)is an important method for surgical treatment of obstlllctive sleep apnea hypopnea syndrome(OSAHS).However,this patient is often accompanied by the risk of difficult tracheal intubation during anesthesia intubation.Traditional preoperative assessment methods such as Mallampati classification,hyperthyroidism,mouth opening and neck circumference have low sensitivity and low specificity..This study mainly used ultrasound to measure the width of the tongue,the distance from the skin to the epiglottis(SED),and the hyomental distances ratios(HMDR)to predict the difficult airway.To explore the feasibility of ultrasound in predicting the difficult airway of patients with OSAHS and to predict the difficult airway with traditional methods.Then the ultrasound method was compared with the conventional evaluation method.MethodAccording to polysomnography(PSG),128 patients with OSAHS,undergoing UPPP and meeting the inclusion criteria were selected,ASAI~II,age 18~70 years,BMI20~40kg/m~2.The airway was assessed by routine methods prior to induction of anesthesia,and the patient's mouth opening,Mallampati grade,hyperthyroidism distance,and neck circumference were recorded.Then the patient was placed in a supine position,and the skin-epiglottic distance(SED)was measured laterally in the plane of the thyroid lingual periosteum using a high-frequency linear array probe(frequency 5 to 12 MHz)by Sonosite ultrasound;Then the tongue width and the hypmental distances ratios(HMDR)was measured using a low-frequency convex array probe(frequency 2 to 5 MHz).Glottic exposure classification were recorded after routine anesthesia induction of intubation.Glottic exposure classification 3 or 4 was defined as difficult airway.According to the classification results,patients were divided into group I:non-difficult airway group,group II:difficult airway group.The data were screened by independent sample t-test Then the viable ultrasound measurements were founded.Draw the receiver operating characteristic curve(ROC curve)about skin to epiglottis distance(SED)and hypmental distances ratios(HMDR),then calculate the cutoff values of SED and HMDR.The sensitivity,specificity,positive predictive value,and negative predictive value were then compared to traditional airway assessment methods.Result1.The skin to epiglottis distance(SED)was significantly higher in patients with difficult airway in group II(2.47±0.18 cm)than in patients with non-difficult airway in group I(2.02±0.13 cm).The difference was statistically significant(P<0.05).2.The hypmental distances ratios(HMDR)of the two groups of patients was(1.26±0.23cm)in group I and(1.03±0.14cm)in group II,the difference was statistically significant(P<0.05).3.There was no significant difference in the width of the tongue between group I and group II(P>0.05).4.Ultrasound prediction method has higher sensitivity,specificity,positive predictive value and negative predictive value than conventional predictive airway method,SED(76.0%,96.1%,82.6%,94.2%),HMDR(80.0%,98.1%,90.9%,95.3%).There were significant differences between the two ultrasound measurements and Mallampati classification,mouth opening and hyperthyroidism(P<0.05).5.There was no significant difference in the prediction of difficult airway between patients of different genders and ages(P>0.05).However,in patients with different severity of AHI,ultrasound measurement showed statistically significant difference in predicting difficulty airway(P<0.05).ConclusionUltrasound measurement of skin to epiglottis distance(SED)and the hypmental distances ratios(HMDR)can be good predictors of difficult airways.Ultrasound-predicted difficult airways have higher sensitivity,specificity,positive predictive value,and negative predictive value than conventional methods for predicting difficult airways.