Clinical assessment of awake endotracheal intubation using the lightwand technique alone in patients with difficult airways

Background There is few study to determine whether the use of the lightwand technique alone could achieve effective, safe and successful awake endotracheal intubation （ETI）, therefore we designed a prospective clinical study to systematically evaluate the feasibility, safety and efficacy of awake ETI using the lightwand alone in patients with difficult airways. Methods Seventy adult patients with difficult airways were enrolled in this study. After the desired sedation with fentanyl and midazolam, airway topical anesthesia was performed with 9 ml of 2% lidocaine, which were in order sprayed in three aliquots at 5 minutes intervals into the supraglottic （two doses） and laryngotracheal areas （one dose） using a combined unit of the lightwand and MADgic atomizer. After airway topical anesthesia, awake ETI was performed using a Lightwand. Subjective assessments by patients and operators using the visual analogue scores （VAS）, and objective assessments by an independent investigator using patients＇ tolerance and reaction scores, coughing severity, intubating conditions and cardiovascular variables were taken as the observed parameters. Results Of 210 airway sprays, 197 （93.8%） were successfully completed on the first attempt. The total time for airway spray was （14.6±1.5） minutes. During airway topical anesthesia, the average patients＇ tolerance scores were 1.7-2.3. After airway topical anesthesia, the mean VAS for discomfort levels that the patients reported was 6.5. Also airway topical anesthesia procedure was rated as acceptable and no discomfort by 94.3% of patients. The lightwand-guided awake ETI was successfully completed on first attempt within 29 seconds in all patients. During awake ETI, patients＇ reaction and coughing scores were 1.9 and 1.6, respectively. All patients exhibited excellent or acceptable intubating conditions. Cardiovascular monitoring revealed that changes of systolic blood pressure and heart rate at each stage of airway manipulations were less than 20% of baseline values. The postoperative follow-up showed that 95.7% of patients had no recall or slight memories of all airway instrumentation. The incidence of postoperative mild airway complications was 38.6%. Conclusion Alone use of the lightwand technique can achieve effective, safe and successful awake ETI in patients with difficult airways.

Difficult airway due to cervical haemorrhage caused by spontaneous rupture of a parathyroid adenoma: A case report

BACKGROUND Cervical haemorrhage due to spontaneous rupture of a parathyroid adenoma is a rare complication that may cause life-threatening acute airway compromise.CASE SUMMARY A 64-year-old woman was admitted to the hospital 1 day after the onset of right neck enlargement, local tenderness, head-turning difficulty, pharyngeal pain, and mild dyspnoea. Repeat routine blood testing showed a rapid decrease in the haemoglobin concentration, indicating active bleeding. Enhanced computed tomography images showed neck haemorrhage and a ruptured right parathyroid adenoma. The plan was to perform emergency neck exploration, haemorrhage removal, and right inferior parathyroidectomy under general anaesthesia. The patient was administered 50 mg of intravenous propofol, and the glottis was successfully visualised on video laryngoscopy. However, after the administration of a muscle relaxant, the glottis was no longer visible and the patient had a difficult airway that prevented mask ventilation and endotracheal intubation. Fortunately, an experienced anaesthesiologist successfully intubated the patient under video laryngoscopy after an emergency laryngeal mask placement. Postoperative pathology showed a parathyroid adenoma with marked bleeding and cystic changes. The patient recovered well without complications.CONCLUSION Airway management is very important in patients with cervical haemorrhage. After the administration of muscle relaxants, the loss of oropharyngeal support can cause acute airway obstruction.Therefore, muscle relaxants should be administered with caution. Anaesthesiologists should pay careful attention to airway management and have alternative airway devices and tracheotomy equipment available.

Airway ultrasound for patients anticipated to have a difficult airway:Perspective for personalized medicine

Airway ultrasound allows for precise airway evaluation,particularly for assessing the difficult airway and the potential for front of neck access.Many studies have shown that identification of the cricothyroid membrane by airway ultrasound is more accurate than digital palpation.However,no reports to date have provided clinical evidence that ultrasound identification of the cricothyroid membrane increases the success rate of cricothyroidotomy.This is a narrative review which describes patients with difficult airways for whom airway ultrasound may have been useful for clinical decision making.The role of airway ultrasound for the evaluation of difficult airways is summarized and an approach to the use of ultrasound for airway management is proposed.The goal of this review is to present practical applications of airway ultrasound for patients predicted to have a difficult airway and who undergo cricothyroidotomy.

Anesthesia management in a pediatric patient with complicatedly difficult airway:A case report

BACKGROUND Reports on perioperative anesthesia management in pediatric patients with difficult airways are scarce.In addition to relatively more difficulties in the technique of endotracheal intubation,the time for manipulation is restricted compared to adults.Securing the airways safely and avoiding the occurrence of hypoxemia in these patients are of significance.CASE SUMMARY A 9-year-old boy with spastic cerebral palsy,severe malnutrition,thoracic scoliosis,thoracic and airway malformation,laryngomalacia,pneumonia,and epilepsy faced the risk of anesthesia during palliative surgery.After a thorough preoperative evaluation,a detailed scheme for anesthesia and a series of intu-bation tools were prepared by a team of anesthesiologists.Awake fiberoptic intubation is the widely accepted strategy for patients with anticipated difficult airways.Given the age and medical condition of the patient,we kept him sedated with spontaneous breathing during endotracheal intubation.The endotracheal intubation was completed on the second attempt after the failure of the first effort.Fortunately,the surgery was successful without postoperative complications.CONCLUSION Dealing with difficult airways in the pediatric population,proper sedation allows time to intubate without interrupting spontaneous breathing.The appropriate endotracheal intubation method based on the patient’s unique characteristics is the key factor in successful management of these rare cases.

Unexpected difficult airway due to severe upper tracheal distortion:A case report

BACKGROUND Difficult airway is a significant cause of anesthesia-associated death and disability.Currently,physical examinations of thyromental distance,mouth opening,Mafampaii classification,etc.combined with X-ray,computed tomography(CT),and other imaging technologies are mainly used to evaluate difficult airways.However,in many special cases,i.e.,emergency surgery,imaging examinations cannot be completed preoperatively.Such patients’airway can only be evaluated through general physical examination,which inevitably increases the likelihood of an unexpected difficult airway during anesthesia.CASE SUMMARY We report a rare case of difficult intubation because of severe upper trachea distortion after induction.Emergency holmium laser lithotripsy was performed under transurethral ureteroscopy because the patient had anuria for 4 d and a creatinine level of 890μmol/L.Due to the urgency of the condition,chest radiography or chest CT was not examined before surgery and the anesthesiologist did not evaluate the airway adequately,resulting in an unexpected difficult airway.CONCLUSION The incidence of tracheal malformation and tracheal stenosis is extremely low,but the risk of hypoxia and even death due to difficult airways is extremely high for such patients.It is recommended to complete preoperative imaging examinations of the airway.For life-threatening emergency patients,a pre-anesthesia reassessment should be performed and surgeons should be prepared to prevent and manage the difficult airway.

A case of radiation-induced difficult airway in a patient with nasopharyngeal carcinoma

In this report, we describe radiation-induced difficult airway management in a patient with nasopharyngeal carcinoma. The patient was presented to receive laparoscopic cholecystectomy for gallbladder stone. He had been diagnosed to have nasopharyngeal cancer about 2 years ago. In operation, after sleeping, the patient was manual controlled ventilation. However, we subsequently found that his neck campaign was limited and mask ventilation was obstructed. We immediately performed oropharyngeal airway, then mask ventilation improved. Fully surface anesthesia with tetracaine atomizing to the root of tongue, larynx wall and piriform recess, the patient was endotracheal intubated with fiberoptic bronchoscope. After intubation, the patient inhaled 2.5% sevoflurane, then esmeron (50 mg) and remifentanyl (0.1 μg/kg every minute) were administrated by intravenous. After the treatment, the patient's life indexes were normal and steady. In conclusion, patients with nasopharyngeal carcinoma (NPC) after radiation therapy should be based on comprehensive evaluation of upper airway and obstructive condition before operation, then perform safe and effective tracheal intubation methods under spontaneous breathing.

Prehospital difficult airway management:old things still work

To the Editor：Airway management is a crucial skill for emergency physician, who＇s often called to deal with difficult airways and requests for quick, simple and effective responses, as the many factors responsible for difficulties might be enhanced by emergency setting.[1] We now have many rescue devices as the LMA, I-gel, but they do not provide a definitive airway, and recent studies evaluating the use of the videolaryngoscopes in emergency show conflicting results.

声带息肉合并喉梗阻症状的治疗方法探讨

目的研究喉显微镜支撑喉镜下CO2激光手术治疗声带息肉合并不同程度喉梗阻患者的疗效。方法选取18例声带息肉伴有不同程度喉梗阻患者为研究对象,均采用纤维支气管镜引导下经鼻气管插管,实施喉显微镜支撑喉镜下CO2激光切除声带息肉手术,术后1个月复查电子喉镜,统计患者治疗总有效率及嗓音功能恢复、并发症以及术后复发等情况。结果 18例患者均一次性插管成功,无气管切开病例,除2例口咽侧壁擦伤外无其他并发症,术后呼吸困难症状改善明显,术后1个月嗓音功能恢复良好,治愈14例(77.78%),好转4例(22.22%),随访半年,无复发病例。结论纤维支气管镜引导下经鼻气管插管,CO2激光显微外科手术是治疗声带息肉合并喉梗阻患者安全、有效、微创的手术方法,值得临床推广应用。

Expert Recommendations for Tracheal Intubation in Critically Ill Patients with Noval Coronavirus Disease 2019

Coronavirus Disease 2019(COVID-19),caused by a novel coronavirus(SARS-Co V-2),is a highly contagious disease.It firstly appeared in Wuhan,Hubei province of China in December 2019.During the next two months,it moved rapidly throughout China.Most of the infected patients have mild symptoms including fever,fatigue and cough,but in severe cases,patients can progress rapidly and develop into acute respiratory distress syndrome,septic shock,metabolic acidosis and coagulopathy.The new coronavirus was reported to spread via droplets,contact and natural aerosols from human to human.Therefore,aerosol-producing procedures such as endotracheal intubation may put the anesthesiologists at high risk of nosocomial infections.In fact,SARSCo V-2 infection of anesthesiologists after endotracheal intubation for confirmed COVID-19 patients have been reported in hospitals in Wuhan.The expert panel of airway management in Chinese Society of Anaesthesiology has deliberated and drafted this recommendation,by which we hope to guide the performance of endotracheal intubation by frontline anesthesiologists and critical care physicians.During the airway management,enhanced droplet/airborne personal protective equitment(PPE)should be applied to the health care providers.A good airway assessment before airway intervention is of vital importance.For patients with normal airway,awake intubation should be avoided,and modified rapid sequence induction is strongly recommended.Sufficient muscle relaxant should be assured before intubation.For patients with difficult airway,good preparation of airway devices and detailed intubation plans should be made.

Shikani Optical Stylet–guided Intubation via the Intubating Laryngeal Airway in Patients With Scar Contracture of the Face and Neck

Objective To evaluate the feasibility of the Shikani Optical Stylet （SOS）-guided inmbation through a new Intubafing Laryngeal Airway （ILA） in anticipated difficult airways caused by scar contracture of the face and neck. Methods Thirty-three adult patients with anticipated difficult airways undergoing selective faciocervical scar plastic surgery under general anesthesia were enrolled in this study. After anesthesia induction, a size 2.5, 3.5 or 4.5 ILA was inserted. Following good lung ventilation being verified, the SOS preloaded with an endotracheal tube was inserted via the ILA. Once the clear vocal cords came into view under the SOS, the endotracheal tube was advanced through glottis into the trachea. Results The ILA provided an effective airway in all patients, lntubation was successful at the first attempt on 22/33 （66.7%） occasions and at the second attempt on 6/33 （18.2%）. Intubation failed in 5 （15.1%） patients who suffered from severe limitation of head extension due to scar contracture of the neck. These patients＇ tracheas were finally intubated using a fibreoptic bronchoscope via the ILA. Conclusions The SOS-guided intubating method via the ILA is a feasible technique in patients with scar contracture of the face and neck. However, in patients with severe limitation of head extension, the use of SOS cannot be recommended. The SOS can be used as an alternative apparatus when the fibreoptic bronchoscope is not available.

Awake fiberoptic intubation and use of bronchial blockers in ankylosing spondylitis patients

BACKGROUND Patients with ankylosing spondylitis(AS)combined with severe cervical fusion deformity have difficult airways.Awake fiberoptic intubation is the standard treatment for such patients.Alleviating anxiety and discomfort during intubation while maintaining airway patency and adequate ventilation is a major challenge for anesthesiologists.Bronchial blockers(BBs)have significant advantages over double-lumen tubes in these patients requiring one-lung ventilation.AIM To evaluate effective drugs and their optimal dosage for awake fiberoptic nasotracheal intubation in patients with AS and to assess the pulmonary isolation effect of one-lung ventilation with a BB.METHODS We studied 12 AS patients(11 men and one woman)with lung or esophageal cancer who underwent thoracotomy with a BB.Preoperative airway evaluation found that all patients had a difficult airway.All patients received an intramuscular injection of penehyclidine hydrochloride(0.01 mg/kg)before anesthesia.In the operating room,dexmedetomidine(0.5μg/kg)was infused intravenously for 10 min,with 2%lidocaine for airway surface anesthesia,and a 3%ephedrine cotton swab was used to contract the nasal mucosa vessels.Before tracheal intubation,fentanyl(1μg/kg)and midazolam(0.02 mg/kg)were administered intravenously.Awake fiberoptic nasotracheal intubation was performed in the semi-reclining position.Intravenous anesthesia was administered immediately after successful intubation,and a BB was inserted laterally.The pre-intubation preparation time,intubation time,facial grimace score,airway responsiveness score during the fiberoptic introduction,time of end tracheal catheter entry into the nostril,and lung collapse and surgical field score were measured.Systolic blood pressure(SBP),diastolic blood pressure(DBP),and heart rate(HR)were recorded while entering the operation room(T1),before intubation(T2),immediately after intubation(T3),2 min after intubation(T4),and 10 min after intubation(T5).After surgery,all patients were followed for adverse reactions such as epistaxis,sore throat,hoarseness,and dysphagia.RESULTS All patients had a history of AS(20.4±9.6 years).They had a Willson's score of 5 or above,grade III or IV Mallampati tests,an inter-incisor distance of 2.9±0.3 cm,and a thyromental(T-M)distance of 4.8±0.7 cm.The average pre-intubation preparation time was 20.4±3.4 min,intubation time was 2.6±0.4 min,facial grimace score was 1.7±0.7,airway responsiveness score was 1.1±0.7,and pulmonary collapse and surgical exposure score was 1.2±0.4.The SBP,DBP,and HR at T5 were significantly lower than those at T1-T4(P<0.05).While the values at T1 were not significantly different from those at T2-T4(P>0.05),they were significantly different from those at T5(P<0.05).Seven patients had minor epistaxis during endotracheal intubation,two were followed 24 h after surgery with a mild sore throat,and two had hoarseness without dysphagia.CONCLUSION Patients with AS combined with severe cervical and thoracic kyphosis should be intubated using fiberoptic bronchoscopy under conscious sedation and topical anesthesia.Proper doses of penehyclidine hydrochloride,dexmedetomidine,fentanyl,and midazolam,combined with 2%lidocaine,administered prior to intubation,can provide satisfactory conditions for tracheal intubation while maintaining the comfort and safety of patients.BBs are safe and effective for onelung ventilation in such patients during thoracotomy.

Emergent use of tube tip in pharynx technique in“cannot intubate cannot oxygenate”situation:A case report

BACKGROUND A“cannot intubate,cannot oxygenate(CICO)”situation is a life-threatening condition that requires emergent management to establish a route for oxygenation to prevent oxygen desaturation.In this paper,we describe airway management in a patient with an extended parotid tumor that invaded the airways during CICO using the endotracheal tube tip in the pharynx(TTIP)technique.CASE SUMMARY A 43-year-old man was diagnosed with parotid tumor for>10 years.Computed tomography and nasopharyngeal fiberoptic examination revealed a substantial mass from the right parotid region with a deep extension through the lateral pharyngeal region to the retropharyngeal region and obliteration of the nasopharynx to the oropharynx.Tumor excision was arranged.However,we encountered CICO during anesthesia induction.An endotracheal tube was used as an emergency supraglottic airway device(TTIP)to ventilate the patient in a CICO situation where other tools such as laryngeal mask airway or mask ventilation were not suitable for this complicated and difficult airway.The patient did not experience desaturation despite sudden loss of definite airway.During tracheostomy,the pulse oximetry remained 100%with our technique of ventilating the patient.The arterial blood gas analysis revealed PaCO_(2)35.7 mmHg and PaO2242.5 mmHg upon 50%oxygenation afterward.CONCLUSION Using an endotracheal tube as a supraglottic airway device,patients may have increased survival without experiencing life-threatening desaturation.

An Audit of the Emergency Airway Service in a Regional Hospital in Singapore

Background: Emergency endotracheal intubations (EEI) performed outside of operating theatre (OT) tend to be more challenging and associated with higher risk of complications. In 2011, with the objective of improving patient outcomes, we set up an Emergency Airway Service (EAS) at our 1000-bed regional hospital, with the aim of providing specialized assistance for outside of OT difficult airway management. Method: A retrospective audit of EAS activation from 12/9/2016 and 27/10/2020 was conducted. EAS forms and electronic medical records were reviewed. We collected information on patient characteristics, EAS activation characteristics and its outcomes. Descriptive analysis method was used to present the collected data. Results: There were a total of 275 activations, of which 268 were analysed. Reasons for activation were anticipated difficult intubation (42.2% n = 113), failed intubation attempt (52.6%, n = 141) and advanced intubation equipment required (5.2% n = 14). Intubation was attempted in 261/268 (97.4%) cases by the EAS team. Of these, 255 (97.7%) cases were successful while 6 (2.3%) cases failed intubation. Of the successful intubations by the EAS team, 208/255 (81.5%) were successful on the first attempt. Out of the 6 unsuccessful intubation cases, 1 case required a rescue cricothyroidotomy and 4 cases required an open tracheostomy. Intubation was deemed easy by the EAS team in 170/261 (65.1%) cases. 64/170 (37.6%) cases were intubated with a video laryngoscope (VL). There were 85 cases (32.3%) classified as difficult intubation by the EAS specialist, 13/85 (15.3%) were intubated using only VL, 54/85 (63.5%) cases were intubated using VL with style/bougie. Conclusion: Audit results showed that providing an experienced and well-equipped team of airway specialists round-the-clock to assist in difficult and potentially difficult endotracheal intubations is justifiable and may reduce complications associated with EEI.

Expert consensus on difficult airway assessment

Background:Identifying a potentially difficult airway is crucial both in anaesthesia in the operating room(OR)and non-operation room sites.There are no guidelines or expert consensus focused on the assessment of the difficult airway before,so this expert consensus is developed to provide guidance for airway assessment,making this process more standardized and accurate to reduce airway-related complications and improve safety.Methods:Seven members from the Airway Management Group of the Chinese Society of Anaesthesiology(CSA)met to discuss the first draft and then this was sent to 15 international experts for review,comment,and approval.The Grading of Recommendations,Assessment,Development and Evaluation(GRADE)is used to determine the level of evidence and grade the strength of recommendations.The recommendations were revised through a three-round Delphi survey from experts.Results:This expert consensus provides a comprehensive approach to airway assessment based on the medical history,physical examination,comprehensive scores,imaging,and new developments including transnasal endoscopy,virtual laryngoscopy,and 3D printing.In addition,this consensus also reviews some new technologies currently under development such as prediction from facial images and voice information with the aim of proposing new research directions for the assessment of difficult airway.Conclusions:This consensus applies to anesthesiologists,critical care,and emergency physicians refining the preoperative airway assessment and preparing an appropriate intubation strategy for patients with a potentially difficult airway.

Comparison of five video-assisted intubation devices by novice and expert laryngoscopists for use in the aeromedical evacuation environment

Background: The critically ill or injured patient undergoing military medical evacuation may require emergent intubation. Intubation may be life-saving, but it carries risks.The novice or infrequent laryngoscopist has a distinct disadvantage because experience is critical for the rapid and safe establishment of a secured airway. This challenge is compounded by the austere environment of the back of an aircraft under blackout conditions. This study determined which of five different video-assisted intubation devices(VAIDs) was best suited for in-flight use by U.S. Air Force Critical Care Air Transport Teams by comparing time to successful intubation between novice and expert laryngoscopists under three conditions, Normal Airway Lights on(NAL), Difficult Airway Lights on(DAL) and Difficult Airway Blackout(DAB), using manikins on a standard military transport stanchion and the floor with a minimal amount of setup time and extraneous light emission.Methods: A convenience sample size of 40 participants(24 novices and 16 experts) attempted intubation with each of the 5 different video laryngoscopic devices on high-fidelity airway manikins. Time to tracheal intubation and number of optimization maneuvers used were recorded. Kruskal-Wallis testing determined significant differences between the VAIDs in time to intubation for each particular scenario. Devices with significant differences underwent pair-wise comparison testing using rank-sum analysis to further clarify the difference. Device assembly times, startup times and the amount of light emitted were recorded. Perceived ease of use was surveyed. Results: Novices were fastest with the Pentax AWS in all difficult airway scenarios. Experts recorded the shortest median times consistently using 3 of the 5 devices. The AWS was superior overall in 4 of the 6 scenarios tested. Experts and novices subjectively judged the Glide Scope Ranger as easiest to use. The light emitted by all the devices was less than the USAF-issued headlamp.Conclusion: Novices intubated fastest with the Pentax AWS in all difficult airway scenarios. The Glide Scope required the shortest setup time, and participants judged this device as the easiest to use. The Glide Scope and AWS exhibited the two fastest total setup times. Both devices are suitable for in-flight use by infrequent and seasoned laryngoscopists. Trial registration: not applicable.

Aspiration as the first-choice procedure for airway management in an infant with large epiglottic cysts: A case report

BACKGROUND Epiglottic cysts is a rare but potentially lethal supraglottic airway pathology in infants due to the high risk of cannot intubation or cannot ventilation.Awake fiberoptic intubation appeared to be the safest technique,but it is very challenging in infants with large epiglottic cysts.Even it has the risk of airway loss.We report that cyst aspiration is an effective treatment as the first-choice procedure for airway management in an infant with large epiglottic cysts.CASE SUMMARY A 46-day-old male infant weighing 2.3 kg presented to the emergency room with difficulty feeding,worsening stridor,and progressive respiratory distress.Epiglottic cysts was diagnosed,but fibro bronchoscopy examination failed,as the fiberoptic bronchoscope was unable to cross the epiglottic cysts to the trachea.The infant was transferred to the operating room for emergency cystectomy under general anesthesia.Spontaneous respiration was maintained during anesthesia induction,and cyst aspiration was performed as the first procedure for airway management under video laryngoscopy considering that the preoperative fibro bronchoscopy examination failed.Then,the endotracheal tube was intubated successfully.Cystectomy was performed uneventfully,and the infant was safely transferred to the intensive care unit after surgery.The infant was extubated smoothly on the third postoperative day and discharged on the eighth day after surgery.On follow-up 1 year after the surgery,a normal airway was found by fibro bronchoscopy examination.CONCLUSION Epiglottic cyst aspiration can be considered the first procedure for airway management in infants with large epiglottic cysts.

Anesthesia management for cesarean section in a pregnant woman with odontogenic infection:A case report

BACKGROUND In recent years,people have paid more attention to oral health with the development of stomatology.Due to the various physiological changes during pregnancy,such as changing hormone levels and immune functions,oral diseases have a high incidence during pregnancy,and the prevention and treatment of oral diseases have also received the attention of both dentists and obstetricians.However,the anesthetic management of pregnant patients with oral disease,especially severe maxillofacial infections,and patients who need surgical treatment or have obstetric emergencies and need to terminate their pregnancy is not clear.CASE SUMMARY This article describes a parturient patient with a severe masseteric space infection who had an emergency cesarean section.CONCLUSION This case report aims to discuss the important anesthetic considerations for these patients.

Induction of Anesthesia with Dexmedetomidine and Sevoflurane for a Pediatric Difficult Airway

Difficult airway is a challenge frequently faced by anesthesiologists. For children recovering from burns with severe scarring contracture in the neck and chest wall, the best strategy is to maintain spontaneous breathing during the induction of anesthesia and to insert a laryngeal mask airway to secure the airway as early as possible.

Effectiveness and Safety of a Novel Approach for Management of Patients with Potential Difficult Mask Ventilation and Tracheal Intubation： A Multi-center Randomized Trial

Background： Patients with potential difficult mask ventilation （DV） and difficult intubation （Dl） are often managed with awake intubation, which can be stressful for patients and anesthesiologists. This prospective randomized study evaluated a new approach, fast difficult airway evaluation （FDAE）. We hypothesized that the FDAE approach would reduce the need for awake intubation. Methods： After obtaining informed consent, 302 patients with potential DV/DI undergoing elective surgeries were randomly assigned to the FDAE group （Group E） and the control group （Group C）. In Group E, patients were gradually sedated, and adequacy of manual mask ventilation during spontaneous breathing was assessed at various sedation levels. Awake intubation was applied in those with inadequate mask ventilation. In Group C, DI was evaluated under local anesthesia. However, the care team could intubate under general anesthesia if the vocal cords were visible. The primary outcome was the rate of awake intubations in both groups and the induction efficiency assessed by the induction time. The secondary outcome was the incidence of serious complications. Results： The rate of awake intubation was significantly lower in Group E than that in Group C （5.81% vs. 36.05%,χ2 = 42.3, P 〈 0.001 ）. The induction time was much shorter in Group E than in Group C （11.85 ± 4.82 min vs. 18.71± 7.85 min, t = 5.39, P 〈 0.001）. There was no significant difl＇erence in the incidence of intubation related complications between the two groups. Patients in Group E had a much lower incidence of recall （9.68% vs. 44.90%, χ2 = 47.68, P 〈 0.001） of the induction process and higher satisfaction levels than patients in Group C （t=15.36, P〈 0.001）. Conclusions： The FDAE significantly reduces the need for awake intubation and improves the efficiency of the intubation process without comprising safety in patients with potential difficult mask ventilation and DI.

Difficult Airway for Patients Undergoing Spine Surgeries

INTRODUCTION The “cannot intubate, cannot ventilate” situation although rare is a nightmare for anesthesiologists. Difficult airway is defined as difficult facemask or supraglottic airway （SGA） ventilation, difficult SGA placement, laryngoscopy, tracheal intubation, or failed intubation. We presented three cases of difficult airway and their airway management.