Incidence Of Difficult Intubation Research Articles

Association of Obstructive Sleep Apnea With Difficult Intubation: Prospective Multicenter Observational Cohort Study.

Obstructive sleep apnea (OSA) has been found to be associated with difficult airway, although there is a paucity of prospective studies investigating thresholds of OSA severity with difficult airway outcomes. The aim of this study was to examine the association between OSA and difficult intubation or difficult mask ventilation. We also explored the utility of the Snoring, Tiredness, Observed apnea, high blood Pressure, Body mass index, Age, Neck circumference, and Gender (STOP-Bang) score for difficult airway prediction. The Postoperative Vascular Complications in Unrecognized Obstructive Sleep Apnea (POSA) trial was an international prospective cohort study of surgical patients 45 years or older with one or more cardiac risk factor presenting for noncardiac surgery, with planned secondary analyses of difficult airway outcomes. Multivariable logistic regression analyses tested associations between OSA severity and predictors of difficult airway with difficult intubation or difficult mask ventilation. Overall, 869 patients without prior diagnosis of OSA were screened for OSA risk with the STOP-Bang tool, underwent preoperative sleep study, and had routine perioperative care, including general anesthesia with tracheal intubation. The primary outcome analyzed was difficult intubation, and the secondary outcome was difficult mask ventilation. Based on the sleep studies, 287 (33%), 324 (37%), 169 (20%), and 89 (10%) of the 869 patients had no, mild, moderate, and severe OSA, respectively. One hundred and seventy-two (20%) had a STOP-Bang score of 0-2 (low risk), 483 (55%) had a STOP-Bang score of 3-4 (intermediate risk), and 214 (25%) had a STOP-Bang score 5-8 (high risk). The incidence of difficult intubation was 6.7% (58 of 869), and difficult mask ventilation was 3.7% (32 of 869). Multivariable logistic regression demonstrated that moderate OSA (odds ratio [OR] = 3.26 [95% confidence interval {CI}, 1.37-8.38], adjusted P = .010) and severe OSA (OR = 4.05 [95% CI, 1.51-11.36], adjusted P = .006) but not mild OSA were independently associated with difficult intubation compared to patients without OSA. Relative to scores of 0-2, STOP-Bang scores of 3-4 and 5-8 were associated with increased odds of difficult intubation (OR = 3.01 [95% CI, 1.13-10.40, adjusted P = .046] and 4.38 [95% CI, 1.46-16.36, adjusted P = .014]), respectively. OSA was not associated with difficult mask ventilation, and only increasing neck circumference was found to be associated (adjusted P = .002). Moderate and severe OSA were associated with difficult intubation, and increasing neck circumference was associated with difficult mask ventilation. A higher STOP-Bang score of 3 or more may be associated with difficult intubation versus STOP-Bang score of 0-2. Anesthesiologists should be vigilant for difficult intubation when managing patients suspected or diagnosed with OSA.

USE OF ULTRASOUND PARAMETERS FOR PREDICTION OF DIFFICULT INTUBATION AND ITS RELATION WITH THE CORMACK AND LEHANE GRADE OF LARYNGOSCOPY

Background and AIMS: Airway ultrasound is novel,safe and noninvasive modality that help in predicting difficult airway.This study aimed todetermine the usefulness of airway ultrasound in order to predict difficult intubation. Method:- This was a hospital based prospective observational study on 100 patients aged 18-60 years of either sex undergoing elective surgery under general anaesthesia with endotracheal intubation.Preoperatively physical airway evaluation was performed byusing six parameters including Modified Mallampati class(MMC), thyromental distance(TMD), sternomental distance(SMD) , inter-incisor (IID)distance , hyomental distance(HMD)and neck circumference(NC). In preoperatively, Airway Ultrasoundwas performed andnoted the ratio of the depth of the pre‑epiglottic space (PES) to the distance from the epiglottis to the mid‑point of the distance between the vocal cords (E‑VC). CL grade was also noted during laryngoscopy. Compared ultrasound parameters with Cormack–Lehane grade. Specificity,Sensitivity, positive predictive value (PPV), negative predictive value (NPV) and accuracywere calculated.Airway ultrasound measurements were compared with physical parametersin predicting Cormack –Lehane grade. Results: The incidence of difficult intubation was 7%. Sensitivity of PES/E-VC ratio was higher than NC, TMD, HMD, IID and SMD but less than Mallampati class. Specificity, PPV was lower than physical parameters.NPV was comparable. Conclusion: Percutaneous airway ultrasound is useful and promising technique for predicting Cormack and Lehane grading but a combination of all these is definitely helpful for better prediction.

Airway Management of Retrosternal Goiters in 22 Cases in a Tertiary Referral Center.

BackgroundThe present study aimed to investigate the incidence and extent of difficult airway management in patients with massive retrosternal goiter.DesignAn 8-year retrospective analysis was performed to identify patients who underwent massive retrosternal thyroidectomy. A total of 22 cases were identified as giant retrosternal goiter, followed by a review of each patient’s preoperative computerized tomography imaging.InterventionsThere were no cases of failed intubation. Twenty patients underwent uneventful tracheal intubation using direct laryngoscopy or Glidescope. Thirteen patients received a muscle relaxant intravenously, and two patients were induced with sevoflurane. Five patients underwent awake tracheal intubation, including awake fiberoptic intubation in three patients. Before entering the operating theatre, the remaining two patients underwent oral tracheal intubation with Glidescope in the emergency department.ResultsTwo patients had tracheal intubation before they entered the operating theatre. Once entering vocal cords, tracheal intubation can pass beyond the site of the tracheal obstruction without difficulty. One patient died because of serious perioperative bleeding owing to the adhesion between the retrosternal goiter and large vessel within the thoracic cavity. One patient experienced dyspnea after extubation and was intubated again.ConclusionIntravenous induction of muscle relaxant using laryngoscopy or Glidescope is feasible in patients with massive benign retrosternal goiter. The incidence of difficult intubation and postoperative tracheomalacia is likely too rare. Furthermore, perioperative bleeding and postoperative airway complication seem frequent.

Anticipating difficult tracheal intubation by observing Modified Mallampati Grade, Thyromental Distance and Upper Lip Bite Test. A prospective observational study

Diagnostic accuracy of various difficult airway predictors in anticipating difficult intubation have been studied in literature. To identify the best combination of bedside difficult airway tests in anticipating difficult intubation.In this study 200 patients between the ages18 -70 years, of American Society of Anaesthesiologists grade I II, posted for elective surgeries under general anaesthesia with intubation were enrolled. Modified Mallampati Grade, Thyromental Distance, Upper Lip Bite Test were noted on airway examination. Intubation difficulty during general anaesthesia was assessed by observing Cormack Lehane Grade, number of intubation attempts, use of external laryngeal pressure, Gum elastic bougie. Airway parameters of 200 patients were analysed in SPSS 20 software for sensitivity, specificity, positive predictive values, negative predictive values in individual tests and in various combinations with each other.: Among 200 patients, incidence of difficult intubation was 7% (14 patients). Patients needing two or more attempts for intubation, gum elastic bougie, external laryngeal pressure were five, eight and 30 respectively. Modified Mallampati Grade had sensitivity 64.3%, specificity 79%. Upper lip bite test had sensitivity 71.4%, specificity 41.9%. Combination of Modified Mallampati Grade with Upper Lip Bite Test had sensitivity 64.3%, specificity 84.9%, positive predictive value 80.9% which were statistically significant. Modified Mallampati Grade, Upper Lip Bite test individually and as combination have better diagnostic value, compared to other airway parameters, in predicting difficult intubation.

Airway Abnormalities in Patients With Congenital Heart Disease: Incidence and Associated Factors

Airway abnormalities complicate the perioperative course of patients with congenital heart disease (CHD), leading to significant morbidity and mortality. The literature describing airway abnormalities in those patients is scarce. This study aimed to determine the incidence of airway abnormalities in CHD patients and identify associated factors, genetic syndromes, and cardiac diagnoses. Retrospective study conducted after institutional review board approval. Tertiary children's hospital. Patients presenting for cardiac diagnostic, interventional, or surgical procedures from 2012 to 2018. A total of 9,495 encounters were reviewed. age >18 years. Methods/Interventions: Age, weight, sex, intubation technique, number of intubation attempts, and difficult intubation (DI) were recorded. Using the International Classification of Diseases, Ninth and Tenth Revisions codes, genetic syndromes, acquired and congenital airway abnormalities, and cardiac diagnoses were identified. Multivariate generalized estimating equations modeling was used to identify independent predictors of airway abnormalities. A total of 4,797 patients, with 8,657 encounters were included. The median age was 1.3 years (interquartile range [IQR]: 0.2-6.0) and weight was 9.2 kg (IQR: 4.3-19.2), and 55% were male. A total of 16.7% had at least 1 genetic syndrome; 8.5% had congenital airway abnormalities and 9.7% acquired. Incidence of DI was 1.1%. The most common syndromes were Down, 22q11.2 microdeletion, and CHARGE. The most frequent congenital airway abnormalities were laryngomalacia and bronchomalacia, and the most frequent acquired were partial and total vocal cord paralysis. The likelihood of a coexistent airway abnormality should be considered in premature CHD patients, weight <10 kg, and in those with specific cardiac lesions and a concomitant genetic syndrome. Preoperative identification of patients at high risk of airway abnormalities is useful in planning their perioperative airway management.

Predictors of difficult endotracheal intubation in the emergency department: a single-center pilot study

Background: Identifying patients who are at risk of difficult endotracheal intubation is crucial in the emergency department. Therefore, this study evaluated the incidence and predictive factors of difficult tracheal intubation in the emergency department. Methods: This was a 17-month prospective observational study. A difficult airway was defined as Cormack &amp; Lehane classification grades III and IV at the first attempt of intubation. Patients who visited the emergency department, underwent traditional endotracheal intubation from participating physicians, and provided informed consent by themselves or via their delegates were enrolled in this study. Univariate associations between patient characteristics and difficult endotracheal intubation were identified, and statistically significant factors were included in a multivariate binary logistic regression model. A generalized association plot was used to show the relationships between variables. Results: A total of 110 patients were enrolled in the study. The incidence of difficult intubation was 35.5% (39/110). In the difficult airway group, significantly higher body mass index (BMI), and incidence of double chin, thick short neck, Mallampati difficulty, small interincisor distance, small thyromental distance, and upper airway obstruction were noted on univariate analysis. A predictive formula for difficult tracheal intubation was successfully established by the combination of four independent predictors: BMI (odds ratio [OR] = 1.270), thyromental distance (OR = 0.614), upper airway obstruction (OR = 4.038), and Mallampati difficulty (OR = 5.163). A cutoff score of four maximized Youden’s index, providing sensitivity (79.5%) and specificity (81.7%) (95% CI: 0.794 to 0.938). Conclusions: We used four predictors of difficult tracheal intubation, namely, BMI, thyromental distance, upper airway obstruction, and Mallampati difficulty, to create a predictive formula. This formula could help emergency physicians to quickly identify and carefully manage patients with difficult endotracheal intubation and consult experts early if necessary.

A clinical prediction rule to identify difficult intubation in children with Robin sequence requiring mandibular distraction osteogenesis based on craniofacial CT measures

BackgroundAirway management is challenging in children with Robin sequence (RS) requiring mandibular distraction osteogenesis (MDO). We derived and validated a prediction rule to identify difficult intubation before MDO for children with RS based on craniofacial computed tomography (CT) images.MethodThis was a retrospective study of 69 children with RS requiring MDO from November 2016 to June 2018. Multiple CT imaging parameters and baseline characteristic (sex, age, gestational age, body mass index [BMI]) were compared between children with normal and difficult intubation according to Cormack−Lehane classification. A clinical prediction rule was established to identify difficult intubation using group differences in CT parameters (eleven distances, six angles, one section cross-sectional area, and three segment volumes) and clinicodemographic characteristics. Predictive accuracy was evaluated by receiver operating characteristic (ROC) curve analysis.ResultsThe overall incidence of difficult intubation was 56.52%, and there was no significant difference in sex ratio, age, weight, height, BMI, or gestational age between groups. The distance between the root of the tongue and posterior pharyngeal wall was significantly shorter, the bilateral mandibular angle shallower, and the cross-sectional area at the epiglottis tip smaller in the difficult intubation group. A clinical prediction rule based on airway cross-sectional area at the tip of the epiglottis was established. Area > 36.97 mm2 predicted difficult intubation while area < 36.97 mm2 predicted normal intubation with 100% sensitivity, 62.5% specificity, 78.6% positive predictive value, and 100% negative predictive value (area under the ROC curve = 0.8125).ConclusionComputed tomography measures can objectively evaluate upper airway morphology in patients with RS for prediction of difficult intubation. If validated in a larger series, the measures identified could be incorporated into airway assessment tools to guide treatment decisions.This was a retrospective study and was granted permission to access and use these medical records by the ethics committee of Guangzhou Women and Children’s Medical Center.Trials registrationRegistration No. ChiCTR1800018252, NaZhang, Sept 7 2018.

Incidence of Difficult Intubation in Obese &amp; Non-Obese Patients Using Intubation Difficulty Scale

Incidence of Difficult Intubation in Obese &amp; Non-Obese Patients Using Intubation Difficulty Scale

Lessons learnt from a difficult intubation scenario: Videolaryngoscopes cannot replace the humble bougie

With the advent of videolaryngoscopes, the incidence of difficult intubation has decreased. Videolaryngoscopes are slowly replacing other airway gadgets such as the fibreoptic bronchoscope and intubating supraglottic devices, especially in institutions where they are freely available. These could not only be the first choice in anticipated difficult intubation but also the first rescue device in unanticipated difficult intubations. A failed intubation can occur despite obtaining a good view of the glottis with a videolaryngoscope. We were unable to intubate an anticipated difficult airway with C-MAC D-blade with a preformed hockey stick-shaped tube using a stylet despite using manoeuvres to optimise laryngeal view. The patient was finally intubated over a gum elastic bougie passed when retaining the videolaryngoscope in place. This case report highlights that a simple gum elastic bougie holds an equally important place on the difficult airway cart as a videolaryngoscope. The use of a gum elastic bougie should be considered as important as a videolaryngoscope in a difficult intubation scenario. It is reasonable to attempt the use of a bougie in the case of failed videolaryngoscope-assisted intubation before switching to another intubating device or a supraglottic airway. A dental consult for poor dentition should be taken prior to surgery whenever possible. Control of bleeding from a broken tooth needs to be done simultaneously and expeditiously even when we have visualised the glottis and are anticipating a successful intubation.

Pre-selection of primary intubation technique is associated with a low incidence of difficult intubation in patients with a BMI of 35 kg/m2 or higher

The incidence of difficult intubation (DI) in obese patients may reach a two-digit figure. No studies have assessed the effect of primary use of special intubation devices on lowering the incidence of DI. We assessed the effect of primary selection of special intubation techniques on the incidence of DI in patients with a BMI of 35 kg/m2 or higher. Data from 546 patients with a BMI of 35 kg/m2 or higher who underwent bariatric surgery at Wolfson Medical Center from 2010 through 2014 was retrospectively extracted and analyzed for demographics, predictors of DI and intubation techniques employed. Difficult intubation was defined as the presence of at least one of the followings: laryngoscopy grade 3 or 4, need for >1 laryngoscopy or intubation attempt, need for changing the blade size, failed direct laryngoscopy (DL), difficult or failed videolaryngoscopy (VL-Glidescope), difficult or failed awake fiberoptic intubation (AFOI) and using VL or awake AFOI as rescue airway techniques. Primary intubation techniques were direct DL, VL and AFOI. We correlated the predictors of DI with the actual incidence of DI and with the choice of intubation technique employed. The overall incidence of DI was 1.6% (1.5% with DL vs. 2.2 with VL + AFOI, p = 0.61). With logistic regression analysis, age was the only significant predictor of DI. Predictors of DI that affected the selection of VL or AFOI as primary intubation tools were Mallampati class 3 or 4, limited neck movement, age, male gender, body mass index and obstructive sleep apnea syndrome. The lower incidence of DI in our study group may stem from the primary use of special intubation devices, based on the presence of predictors of DI.

Goitre-Related Factors for Predicting Difficult Intubation in Patients Scheduled for Thyroidectomy in a Resource-Challenged Health Institution in North Central Nigeria.

Airway management problems may arise when intubating patients with goitre scheduled for thyroidectomy. Goitres are not uncommon in sub-Saharan Africa, thyroidectomy being the main treatment. The aim of this study was to determine incidences of difficult intubation (DI), failed intubation (FI) and predictors of DI using a modified intubation difficulty score (IDS). One hundred and twenty-five consenting patients with goitre scheduled for thyroidectomy were recruited. Goitre-related factors (GRF) of duration of illness, diagnosis, neck circumference, tracheal deviation and narrowing and retrosternal extension were recorded as well as Mallampati classification and BMI. At intubation, modified IDS was determined for each patient. Patients with modified IDS ≤ 5 were categorized as easy intubation group (E), and those with modified IDS >5 were categorized as difficult intubation group (D). The GRF of all patients in group D were compared with matched patients in group E. Incidence of DI was 13.6% with 2 (1.6%) cases of failed intubation. Comparing groups D and E, duration of illness was 4.28 ± 3.78 years in group D versus 7.44 ± 7.63 years group E, p = 0.1353. Neck circumference was 41.42 ±5.30 cm in group D versus 37.43±2.68 cm in group E, p = 0.0200. Tracheal deviation, narrowing and retrosternal extension, and surgical diagnosis were not significantly different among both groups. Incidence of DI was 13.6% and that of FI was 1.6%. Neck circumference was found to be a predictor of difficult intubation in goitre patients scheduled for thyroidectomy using the modified IDS.

Prevailing practices in airway management: a prospective single-centre observational study of endotracheal intubation.

Airway management during anaesthesia has potential difficulties and risks. We aimed to investigate the utility of routine airway assessment for predicting difficult tracheal intubation, review the prevailing practice of videolaryngoscope use amongst anaesthetists in a teaching hospital and determine the incidence of intraoperative and postoperative airway-related complications. A prospective observational study of 1,654 patients undergoing general anaesthesia with endotracheal intubation over a seven-month period was performed. Data regarding airway and anaesthetic management was collected and analysed. Videolaryngoscopes were used as the first-choice equipment in 60.5% of the cohort. The incidence of difficult intubation was 2.1%, of which 45.7% of cases were unanticipated. The sensitivity of airway assessment was 54.3%, with a positive predictive value of 8.1%. When difficult intubation was anticipated, more videolaryngoscopes were used as the first equipment of choice compared to the Macintosh laryngoscope (p < 0.001). In the Macintosh group, more patients required a change of airway equipment (p = 0.015), but the number of intubation attempts was similar (p = 0.293). The incidence of intraoperative (p = 0.920) and postoperative complications (p = 0.380) were similar in both groups. Using the current predictors of difficult intubation, half of the difficult airways we encountered were unanticipated. Videolaryngoscopes were preferred when difficulty was anticipated and were also used in routine tracheal intubation.

Airway management of difficult intubation in the pediatric population: A single center experience

Awareness and the management of the difficult airway in children are crucial. Although the incidence of difficult intubation in children is believed to be lower than in adults, there is insufficient data regarding it. The aim of this study was to determine what airway management techniques are being applied in the difficult airway situation, by a group of experienced Consultant Anesthetists, in a large pediatric center. The study conducted over a 2-year period, in a large pediatric hospital. For a 2-year period beginning from September 2014, consultant anesthetists completed pro-forma following all pediatric anesthesia procedures in which tracheal intubation was difficult. The collected information included: patient demographics; airway assessment; anesthetic technique and airway management strategies employed; and reasons of failure in intubation attempts. There were 50 cases which were assessed as difficult intubation, and 80% of the cases had an anticipated difficult intubation report with 40% having a history of previous difficult intubation. Fiberoptic Bronchoscope (FOB) was the first-choice rescue technique in 84% of the patients; 92% of oral FOB and 71% of nasal FOB were successful. Six cases required surgical airway as surgical tracheostomy. This study created a screenshot of the various methods used when we were faced with a difficult airway management in pediatric population. Fiberoptic intubation remains overall the best method whereas no method was 100% successful. The majority of the patients had anticipated difficult airway, which opportunely allows planning for surgical airway with other teams such as Ear-Nose Throat and pediatric surgery.

Comparison of the Shikani Optical Stylet and Macintosh Laryngoscope for Orotracheal Intubation with Topical Anesthesia in Critically Ill Patients

Background: Emergency airway management outside operating room (OR) is associated with a higher incidence of difficult intubations. The Shikani optical stylet (SOS) has been shown to improve first-attempt success rates compared with the classic Macintosh laryngoscope (ML) in patients with difficult airway inside the operating room (OR). Objective: In this randomized controlled clinical trial, the effectiveness of using a SOS as the primary intubation device was assessed during urgent endotracheal intubations (UEI) in conscious, critically ill patients outside the OR. Method: Sixty conscious critically ill patients from May 2018 to March 2018 were randomly assigned to undergoing intubation guided by the SOS (group S, n = 30) or the Macintosh laryngoscope (group M, n = 30) in ChanCheng Center Hospital,. After application of airway topical anesthesia and intravenous sedatives, endotracheal intubations were performed. The primary measured outcome was first-attempt intubation success rate. Secondary outcomes included ultimate success, the number of attempts, the duration of intubation, and the adverse effects or complications of intubation. Result: The rate of successful intubation at the first-attempt was superior with the SOS as compared with the ML (93.3% vs 63.3%, P = 0.005), the average number of attempts required for successful tracheal intubation (1.0 ± 0.3 vs 1.5 ± 0.8, P = 0.004), the duration of intubation (18.8 ± 11.9 vs 26.8 ± 15.6, P = 0.028), and the incidences of hemorrhage in the oropharyngeal mucosa (0 vs 28.6%, P = 0.006) were all improved significantly with use of the SOS compared with the ML. Conclusion: This study suggested SOS could be used as the effective device when UEIs are performed by experienced operators in conscious, critically ill patients outside the operating room.

The Importance of Neck Circumference to Thyromental Distance Ratio (Nc/Tm Distance Ratio) as a Predictor of Difficult Intubation in Obese Patients Coming for Elective Surgery under General Anaesthesia in a Teritatry Care Hospital - A Prospective Observational Study

BACKGROUND AND OBJECTIVES : This study was done to assess the ability of neck circumference to thyromental distance ratio (NC/TM distance ratio) for predicting difficult intubation among obese patients coming for surgery under general anaesthesia. It enabled us to compare NC/TM distance ratio to routinely used Mallampati score and neck circumference as reliable tests for predicting difficult intubation. This study also identified incidence of difficult intubation among obese individuals. PATIENTS AND METHODS : After approval of institutional review board and ethical committee of Christian Medical College Vellore, 250 obese patients (body mass index greater than or equal to 30) within time frame of September 2014 and March 2015 was assessed preoperatively with the help of performa after obtaining informed consent. Neck circumference / thyromental distance ratio (NC/TM distance ratio) was calculated from the performa. Validated Intubation difficulty score (IDS score) for each obese patient was assessed intra operatively by the anaesthetist who performed intubation . The entire study population were divided into easy and difficult intubation groups based on the IDS score. IDS score greater than or equal to five was considered as difficult intubation. NC/TM distance ratio greater than or equal to five was correlated with IDS score greater than or equal to five. The study assessed the statistical significance of NC/TM distance ratio and difficult intubation by univariate and multivariate logistic regression analysis and its comparison with Mallampati score and neck circumference with respect to sensitivity / specificity/ positive predictive value and negative predictive value. The study also calculated the incidence of difficult intubation among obese patients. RESULTS : Binary univariate logistic regression analysis of predictors of difficult intubation showed age greater than sixty, increased neck circumference, decreased thyromental distance, modified Mallampati test, NC/TMD ratio ≥ 5 as statistically significant variables that were associated with a difficult intubation (p ≤ 0.05). Binary multivariate logistic regression analysis showed only neck circumference (p=0.030 [odd ratio 2.519 (1.094-5.802)] and NC/TMD ratio (p <0.001 [odd ratio 23.680 (10.638-52.713)] independently predicted difficult intubation. However NC/TMD ratio had higher specificity / PPV and larger AUC on an ROC curve compared to neck circumference. The incidence of difficult intubation among obese patients was 20.8 %. INTERPRETATION AND CONCLUSIONS : Among obese patients, NC/TMD ratio can be considered as a better preoperative predictor of difficult intubation and incidence of difficult intubation among them was as high as 20.8 percent.

Trachway video intubating stylet allows for optimization of electromyographic endotracheal tube placement for monitored thyroidectomy.

Endotracheal tube-based surface electrodes are now commonly applied to measure evoked electromyographic (EMG) response of the vocal cord during monitored thyroidectomy. The aim of the study was to determine the incidence of difficult intubation and to assess the effectiveness of using video-assisted intubating stylet (Trachway) for EMG tube placement in patients undergoing monitored thyroidectomy. Medical records were collected from consecutive patients undergoing thyroid surgery before and after implementation of the protocol. A total of 748 patients intubated with EMG tube for monitored thyroidectomy by the same team were enrolled in this study. Patient allocation was based on intubation technique either conventional direct laryngoscopy (n=336) or Trachway (n=412). The intubation difficulty was assessed and analyzed. The overall incidence of difficult intubation was 4.4%. Incidence of difficult intubation was significantly lower in patients with the Trachway procedure (2.7%) than direct laryngoscopy (6.5%, P=0.01). The incidence of "unable to intubate" (>3 attempts, or change airway device or anesthesiologist) also significantly reduced from 2.3% to 0.5% after introduction of the Trachway intubating stylet (P=0.02). We conclude that the incidence of difficult intubation was significantly lower with Trachway than direct laryngoscopy. The Trachway video-intubating stylet is useful and helpful to reduce EMG tube intubation difficulty for monitored thyroidectomy.

The performance of neck circumference and other airway assessment tests for the prediction of difficult intubation in obese parturients undergoing cesarean delivery

BackgroundPregnancy and obesity each increase the chance of difficult tracheal intubation. This study assessed the performance of the neck circumference and other bedside tests in predicting difficult intubation, and aimed to identify the optimal cutoff point of the test(s) with the highest performance. MethodsParturients with a body mass index ≥30kg/m2, undergoing a cesarean delivery employing conventional tracheal intubation, were enrolled. Preoperative neck circumference, sternomental distance and modified Mallampati test were examined. Difficult intubation was defined as intubation difficulty scale score ≥5. ResultsFive hundred and seventy parturients of mean body mass index 34.1 (±SD 3.8) kg/m2 were recruited. The incidence of difficult intubation was 3.5%. The performance of the neck circumference test, conducted with the patient sitting or supine, and using the area under the receiver operating characteristic (ROC) curves, was 0.6 (95% CI 0.5 to 0.7) and 0.6 (95% CI 0.4 to 0.7) respectively. The area under the ROC for the modified Mallampati test was 0.6 (95% CI 0.5 to 0.7) and for the sternomental distance test was 0.7 (95% CI 0.6 to 0.8). A sternomental distance less than 14.5cm, and a ratio of neck circumference in the sitting position to sternomental distance of greater than or equal to 2.7, were optimal cutoff points to identify difficult intubation. ConclusionThe neck circumference, the sternomental distance, the modified Mallampati test and the ratio of neck circumference to the sternomental distance show limited performance as screening tests to predict difficult intubation among obese parturients.

Are cardiac surgical patients at increased risk of difficult intubation?

Background and Aims:Safe airway management is the cornerstone of contemporary anaesthesia practice, and difficult intubation (DI) remains a major cause of anaesthetic morbidity and mortality. The surgical category, particularly cardiac surgery as a risk factor for DI has not been studied extensively. The aim of this study was to test the hypothesis whether cardiac surgical patients are at increased risk of DI.Methods:During the study, 627 patients (329 cardiac and 298 non-cardiac surgical) were enrolled. Pre-operative demographic and other variables associated with DI were assessed. Patients with Cormack Lehane grade III and IV or use of bougie in Cormack grade II were defined as DI. The incidence of anticipated and unanticipated DI was assessed. Factors associated with DI were described using univariate and multivariate logistic regression models.Results:The overall incidence of DI was 122/627 (19.46%). The incidence of DI was higher in cardiac surgery patients (24%) as compared to non-cardiac surgery patients (14.4% P = 0.002). On multivariate analysis, factors independently associated with DI were greater age, male sex, higher Mallampati grade, and anticipated DI, but not cardiac surgery. The incidence of unanticipated DI was 48.1% and 53.4% in cardiac and non-cardiac surgery patients, respectively.Conclusion:Although there was a higher incidence of DI in cardiac surgical patients, cardiac surgery is not an independent risk factor for DI. Rather, other factors play more important role. About half of the DI both in cardiac and non-cardiac surgeries were unanticipated.

Correlation between preoperative ultrasonographic airway assessment and laryngoscopic view in adult patients: A prospective study.

Background and Aims:Difficult tracheal intubation is associated with serious morbidity and mortality and cannot be always predicted based on preoperative airway assessment using conventional clinical predictors. Ultrasonographic airway assessment could be a useful adjunct, but at present, there are no well-defined sonographic criteria that can predict the possibility of encountering a difficult airway. The present study was conducted with the aim of finding some correlation between preoperative sonographic airway assessment parameters and the Cormack–Lehane (CL) grade at laryngoscopic view in adult patients.Material and Methods:This was a prospective, double-blinded study on 130 patients undergoing elective surgery under general anesthesia. Preoperative clinical and ultrasonographic assessment of the airway was done to predict difficult intubation and was correlated with the CL grade noted at laryngoscopy. The sensitivity, specificity, positive predictive value, and negative predictive values of the parameters were assessed.Results:The incidence of difficult intubation was 9.2%. Among the clinical predictors, the modified Mallampati classification had the maximum sensitivity and specificity, and among the sonographic parameters, the skin to epiglottis distance had the maximum sensitivity and specificity to predict difficult laryngoscopy. A combination of these two tests improved the sensitivity in predicting a difficult laryngoscopy.Conclusions:The skin to epiglottis distance, as measured at the level of the thyrohyoid membrane, is a good predictor of difficult laryngoscopy. When combined with the modified Mallampati classification, the sensitivity of the combined parameter was found to be greater than any single parameter taken alone.

Abstract PR204

Background & Objectives: Pregnancy induced anatomical and physiological changes in the airway makes airway management difficult in obstetric patients, thus the preoperative evaluation of the airway is important for obstetric patients. The first aim of this study was determine the effectiveness of the modified mallampati test, the interincisor, sternomental, thyromental distances, the upper limb bite tests and the second aim was to access the effectiveness of the combination of the upper limb bite test with the other tests in obstetric patients. Materials & Methods: 250 pregnant women scheluded for caesarean section were analyzed. Age, height and weight of the patients were all collected. Preoperative airway evaluation was done by using modified mallampati test. The interincisor, sternomental and thyromental distances and the upper limb bite test was performed. The laryngoscopy difficulty was evaluated by using Cormack-Lehane classification. Results: No statistically significant difference was found between age, height and weight (p>0.05). The modified mallampati test, interincisor, sternomental, and thyromental distances revealed a lower number than the number of easy intubations determined by the Cormack-Lehane classification and a higher number than the case number of difficult intubations (p<0.05). Combination of the upper limb bite with the other tests revealed high sensitivity and specificity than single tests. The incidence of difficult intubation was found as 10,4 %. Conclusion: In conclusion, we suggest combination of the upper limb bite with the other tests to predict difficult airway instead of using a single tests.