The Obstructive Sleep Apnea Hypopnea Syndrome And Difficult Airway

BackgroundObstructive sleep apnea hyponea syndrome(OSAHS) is a breathing disorder during sleep that results from a complete or partial obstruction of the upper airway,or is accompanied by respiratory drive reduced,and thereby results in repeated chronic intermittent hypoxia, carbon dioxide retention, repeated arousals and sleep structure changes. The systemic nervous stress response of patients is induced with nocturnal intermittent hypoxia and hypercapnia, which can cause multiple organ dysfunction,patients can be associated with a series of serious diseases which include:hypertension, coronary heart disease, arrhythmia, heart failure, stroke, diabetes and insulin resistance so on.OSAHS is considered as an independent risk factor for a variety of systemic disease. At the same time, duing to repeated arousals and sleep disruption,the incidence of occupational accidents and traffic accidents increase significantly to parients with OSAHS. Thus, OSAHS has become a serious disease which affects people's life quality and the health to people's survival.Since20th fifties and sixties,the clinical and basic researches on OSAHS have been carried out in the United States and European countries, with the gradual awareness in pathogenesis of OSAHS and epidemiological survey data on OSAHS,OSAHS recognized as a high incidence of systemic diseases has been paied more and more attention. In1979, the America Association of Sleep divided the sleep apnea syndrome into three categories:obstructive sleep apnea syndrome, central sleep apnea syndrome and mixed sleep apnea syndrome. In1994, the America Association of Sleep Disorder considered sleep apnea syndrome as one of the diseases of sleep disorder. In1996, sleep medicine was identified as a medical branch by the America Association of Medicine. In1999, the American Academy of sleep medicine(AASM) was established,which replaced the American Association of Sleep Disorders.The clinical guidelines on OSAHS have been formulated and revised by AASM since then.These guidelines can standard the treatment of OSAHS and avoid risks in managing OSAHS patients.Surgery was an important means to treat OSAHS patients, in the early1970th, tracheotomy and tonsillectomy were tried, In1982,uvulopalatopharyngoplasty(UPPP) was firstly developed to treat OSAHS patients by Fujita.UPPP has been improved to preserve uvula physiological function since1997. According to the report, recent efficiency of UPPP was50%～60%, the long-term efficiency was inferior to the recent efficiency.The fact that death is caused by perioperative complications especially acute airway obstruction have caused attention of people,practice guidelines for the perioperative management of patients with obstructive sleep apnea was recommended by the American Society of anesthesiologists in2006,which focused on difficult airway management to patients with obstructive sleep apnea perioperatively.Case report about OSAHS was begun in1980th in our country, clinical researches have increased year by year since then. In1987,professor Huang Xizhen set up the first sleep medicine laboratory in our country in Peking Union Medical College Hospital. With OSAHS being recognized, sleep laboratories in some hospitals have been established one after another, sleep laboratories have begun popular for the nearest ten years, sleep monitoring and the diagnosis of OSAHS can be finished in these laboratories. OSAHS has been gradually recognized as a disease associated with multisystem and harmful to health. However, in our country, physicians lack the ability in recognizing patients with OSAHS in general, there are differences in ability to deal with patients with OSAHS between physicians specialized in different medicine.Zhong Nanshan called for further development of OSAHS study and cooperaton between different medical speciality.With the treatment interventions to OSAHS, the need to be operated for OSAHS patients has increased year by year, the death duing to airway obstruction in the perioperative period has been reported repeatedly,which arouse our attention once again. The failure of tracheal intubation has been considered as primary cause of death to OSAHS patients perioperatively. Furthermore, article reports showed that difficult tracheal intubation was associated with postoperative complications including:bleeding, cardiac accidents and respiratory adverse outcomes. Unfortunately, all retrospective studies in severe complications and death complications to OSAHS patients came from otolaryngologists' analysis,anesthesia-related complications induced by failure in tracheal intubation to OSAHS patients haven't caused enough vigilance to anesthesiologists.At present,OSAHS can be diagnosized and treated in limited hospitals, anesthesiologists have limited chance to deal with OSAHS patients,which should be the partial reason why anesthesiologists lack enough knowledge on OSAHS.However,the truth is that anesthesiologists haven't paied enough attention on managing OSAHS patients with difficult airway.The obstructive sleep apnea knowledge and attitudes questionnaire was developed by Schotland to judge physicians'knowledge about OSAHS. Southwell,Tamay and Uong EC carried out surveies to evaluate physicians and pediatricians'knowledge about OSAHS with OSAKA questionnaire,too. OSAKA questionnaire was considered as a useful tool to judge physician's knowledge on OSAHS,to evaluate the reasonability of medical course setted to medical students,and to assess the need of the continuous medical education to physicians.There is no survey among anesthesiologists with OSAKA questionnaire in our country.In the United States and other countries,with the surgery being done to treat OSAHS,anesthesiologists had begun the study on the relationship between OSAHS and difficult intubation or difficult mask ventilation.Factors including obesity,the severity of OSAHS and Mallampati classification had been considered associated with difficult airway among OSAHS patients. But,the results in different reports were not the same,no single risk factor or certain risk factors were sure to predict difficult airway in OSAHS patients,some reports were conflicting. Study on the relationship between OSAHS and difficult airway is still lacked in our country. Our study included two sections.In the first section,we carried out a survey about OSAHS among anesthesiologists with OSAKA questionnaire.We revised the questionnaire with knowledge associated with anesthesia according to practice guidelines for the perioperative management of patients with obstructive sleep apnea developed by ASA.We hoped that anesthesiologists can pay more attention on OSAHS and be active in continuous medical education on OSAHS after finishing the questionnaire,so that emergency accidents to OSAHS patients can be avoided or be decreased duing to anesthesiologists' neglect.In the second section,we established Logisogistic regression model to screen risk factors for difficult airway among OSAHS patients.According to recommendations in managing OSAHS patients suggested by ASA and Chinese Medical Association of Anesthesiology,combining with the characteristics of OSAHS patients,we determined to observe certain variables as risk factors for difficult airway,which included:body mass index(BMI),neck circumference(NC),waist circumference(WC),thyromental distance(TMD),interincisor distance (ICD), horizontal length of the mandible(HLM), the modifed Mallampati score and the Cormack and Lehane's classification so on. We hoped that risk factors predicted to difficult airway can be distinguished from confounding factors, so that emergency airway obstruction can be avoided in advance,anesthesia-related morbidity and death in the perioperative period can be decreased. OBJECTIVE TO measure the anesthesiologists'knowledge and attitudes about obstructive sleep apnea (OSA)and assess the need for additional educational programs focusing on OSA.METHODS We was permitted to use questionnaire developed by Schotland HM,the Obstructive Sleep Apnea Knowledge and Attitude Questionnaire was translated into Chinese,400questionnaires were distributed to anesthesiologists from Shandong Province. The Questionnaire included two sections regarding knowledge and attitudes about obstructive sleep apnea.The first section was about knowledge on OSA, with eighteen statements covering five domains:(1) epidemiology,(2) pathophysiology,(3) symptoms,(4) diagnosis, and (5) treatments. The score of "true"was1; the other choice was scored0. The second section was about attitudes on OSA, attitude choice was measured on a five-point Likert scale, ranging from1to5(1, strongly disagree;2,disagree;3, neither agree nor disagree;4, agree; and5,strongly agree). The OSAKA questionnaire finished completely by Anesthesiologists was valid,which score about knowledge and attitudes was documented respectively. The relationship between knowledge and attitudes was analysized.RESULTS A total of321questionnaires were completed. The mean total knowledge scores were11.21,ranging from2o17.The total correct score ratio was62%. The knowledge about pathophysiology of obstructive sleep apnea gained the highest correct ratio,which was86%.The score of knowledge on treatment to patients with obstructive sleep apnea was the lowest,the correct score ratio was33%.The ratio of positive attitude in recognizing OSA patients,managing OSA patients during the period of surgery and managing OSA patients postoperatively was51.71%,66.36%,55.46%respectively.The knowledge score positively associated with particents's job title and attitude score.None of the dependent variables,such as sex, age, education, and working in different levele hospital,affected the score. CONCLUSION The study showed that anesthesiologists lacked adequate knowledge about OSA, they had few confidience in managing OSA patients. It is necessary to develop special training program of OSA regularly for anesthesiologists after gradution. Objectives The purpose of this study was to find risk factors for difficult mask ventilation and difficult intubation in OSA patient,and to predict decreasing the incidence of difficult airway.Methods120OSA patients diagnosed by polysomnography were enrolled in the study, The characteristics of the OSA patients were documented,which included:gender,age,body mass index(BMI), the lowest oxygen saturation(LSa02), the longest sleep apnea time(LSAT),apnea-hypopnea index(AHI), neck circumference (NC), waist circumference(WC),thyromental distance(TMD),interincisor distance (ICD), horizontal length of the mandible(HLM),The modifed Mallampati score of the oropharynx view and the Cormack and Lehane's classification of the glottis visualized were assessed, difficult mask ventilation and difficult intubation were recorded. Correlation analysis identified potential risk factors for difficult mask ventilation and difficult intubation,?<0.05was regarded as significant.Factors that had significant association with difficult mask ventilation and difficult intubation on correlation analysis were then subjected to stepwise multiple logistic regression analysis to evaluate confounding among these predictors.Results The mean age was39.98years old,the mean BMI was29.45kg/m2, the mean waist circumference and neck circumference was100.5cm and42.08cm respectively The ratio of difficult mask ventilation and difficult intubation was41.7%and25.8%respectively. Risk factors for difficult intubation were the Cormack and Lehane's score (OR=7.799), AHI(OR=1.045),and ICD(OR=0.090).The predicting risk factors for difficult mask ventilation were neck circumference (OR=1.857) and the Mallampati score(OR=12.508).BMI and waist circumference were not risk factors for predicting difficult intubation,.but were correlated with difficult mask ventilation. Conclusion Obesity especially central obesity in OSA patients are common. The incidence of difficult mask ventilation and difficult intubation is high in OSA patients. The Mallampati score and the Cormack-Lehane score are considered as two important risk factors to judge the difficult airway in OSA patients.Neck circumference is important to predict difficult mask ventilation.BMI and waist circumference are not independent risk factors for predicting difficult intubation in OSA patients,but have the correlationship with difficult mask ventilation.AHI and ICD are associated with difficult intubation.