Difficult Intubation In Patients Research Articles

Incidence and Predictors of Difficult Intubation in Patients Undergoing Thyroid Surgery

Introduction: Thyroid enlargement is considered a risk factor for challenging direct laryngoscopy and intubation. Airway management in patients with thyroid swelling presents unique challenges, requiring thorough preparation for potential difficult airways. Although airway management in the overall population has been thoroughly researched, there is a scarcity of literature specifically addressing airway management in individuals who have thyroid enlargement. Aim: To evaluate the incidence of difficult intubation in patients undergoing thyroid surgery, utilising the Intubation Difficulty Score (IDS). Materials and Methods: This cross-sectional observational study was conducted among 258 patients in the Department of Anaesthesiology, Government TD Medical College, Alappuzha, Kerala, India. Various parameters including Modified Mallampati score, neck circumference, Body Mass Index (BMI), inter-incisor distance, retrognathia, neck extension, thyromental distance, tracheal deviation, and tracheal compression were assessed for all patients with thyroid swelling. The incidence of difficult endotracheal intubation was analysed using the IDS and the time taken for successful intubation was recorded. Data were presented as mean±standard deviation (SD), frequencies, and percentages. The association between variables was analysed using the Chi-square test. Results: Thyroid disorders were more common in females 220 (85.3%) than in males 38 (14.7%). The variables such as BMI, Mallampati score, thyromental distance, inter-incisor distance, and neck mobility were not found to be associated with difficult intubation. However, increased neck circumference (>43 cm) was statistically significant (p-value=0.007) in relation to difficult intubation. According to IDS, 94.2% of patients had easy intubation, while 5.8% experienced difficult intubation. In terms of intubation times, 72.5% of patients were intubated within 10-15 seconds, 24.4% within 16-20 seconds, and 3.1% took longer than 20 seconds. Conclusion: Thyroid surgery itself is not an independent predictive factor for difficult intubation. Among the predictive factors in the study population, a neck circumference greater than 43 cm was found to be associated with difficult endotracheal intubation during thyroid surgery

Comparison of Upper Lip Bite Test and Modified Mallampati Classification as Predictor of Difficult Intubation in Patients for Surgery under General Anaesthesia

Comparison of Upper Lip Bite Test and Modified Mallampati Classification as Predictor of Difficult Intubation in Patients for Surgery under General Anaesthesia

Prediction of difficult laryngoscopy / difficult intubation cases using upper airway ultrasound measurements in emergency department: a prospective observational study

IntroductionDifficult laryngoscopy and intubation are serious problems among critically ill patients in emergency department (ED) so utility of a rapid, accurate and noninvasive method for predicting of these patients are necessary. Ultrasonography has been recently used in this regard and this study was conducted to investigate the correlation of some introduced upper airway ultrasound parameters with difficult laryngoscopy / difficult intubation in patients referred to the ED.MethodIn this prospective observational study all patients ≥ 18-year-old who had an indication for rapid sequence intubation (RSI) were included. Ultrasound parameters including Hyoid Bone Visibility (HBV), Distance from Skin to Hyoid Bone (DSHB), Distance from Skin to Vocal Cords (DSVC), Distance from Skin to Thyroid Isthmus (DSTI), and Distance between Arytenoids Cartilages (DBAC) were measured in all cases. The patients underwent RSI and thereafter the patients’ baseline characteristics, Cormack-Lehane grade, number of attempted laryngoscopy were recorded in a pre-prepared check list and compared with measured ultrasound parameters. The “difficult laryngoscopy” was defined as Cormack-Lehane classification grades III/IV; and need for more than 3 intubation attempts was considered as “difficult intubation”.ResultsOne hundred and twenty-three patients (52% male) were included of whom 10 patients (8.1%) were categorized as difficult laryngoscopy cases; and just 4 (3.3%) cases underwent more than 3 laryngoscopy attempts who considered as difficult intubation cases. The mean age of the patients in non-difficult and difficult intubation groups were 69.2 ± 15.16 and 68.77 ± 17.37 years, respectively (p > 0.05). There was no significant relationship between difficult laryngoscopy and HBV (p = 0.381) but has significant correlation with difficult intubation (p = 0.004). The DSHB had a significant correlation with difficult laryngoscopy (p = 0.002) but its correlation with difficult intubation was not significant (p = 0.629). The DSVC and DSTI had a significant relationship with both difficult laryngoscopy (p = 0.003 and p = 0.001), and difficult intubation (p = 0.025 and p = 0.001). The DBAC had not significant correlation neither with the difficult laryngoscopy (p = 0.142), nor with difficult intubation (p = 0.526).ConclusionThe findings showed that ultrasound parameters including soft tissue DSHB, DSVC and DSTI could be proper predictors of difficult laryngoscopy. Also, HBV, DSVC and DSTI may be proper predictors for difficult intubation. But DBAC was not useful in this regard.

PREOPERATIVE SINGLE ANTHROPOMETRIC SCREENING TESTS OF DIFFICULT FACE MASK VENTILATION AND DIFFICULT DIRECT LARYNGOSCOPY INTUBATION IN PATIENTS UNDERGOING OTORHINOLARYNGOLOGICAL SURGERY: A PROSPECTIVE, OBSERVATIONAL, SINGLE CENTER STUDY.

The aim of this study was to assess preoperative airway history data and single anthropometric screening tests of difficult face mask ventilation (FMV) and difficult direct laryngoscopy intubation (DLI) in otorhinolaryngological surgery. Final analysis included 62 patients aged ≥14 years undergoing elective surgery with endotracheal intubation at a single center during a one-month period. Data on difficult intubation history, airway symptoms and pathology related to difficult airway were prospectively collected. Han scoring classification of FMV and Intubation Difficulty Score (IDS) were used. There were 14 (22.6%) patients with a history of current airway tumors or abscesses. Only two (3.2%) patients were preoperatively evaluated as anticipated difficult airway. Both were slightly difficult to ventilate and scored IDS 5 and IDS 8. FMV was graded as easy in 50 (80.5%), slightly difficult in 10 (16.1%) and difficult in 2 (3.2%) cases. There were 29 (46.78%) slightly difficult DLIs and one (1.6%) case of difficult DLI. The study confirmed clinically relevant incidence of difficulties with FMV and DLI in otorhinolaryngologic surgery patients. However, there should be stronger evidence to identify a single preoperative variable predicting difficult airway.

Predicting difficult intubation: the hyomental distance ultrasound evaluation is superior to the thyromental distance

BackgroundHyomental distance (HMD), an anatomical feature of the upper airway, can be measured precisely by ultrasonography. But the sensitivity and specificity of HMD compared to thyromental distance (TMD) to predict difficult airways is still unknown. MethodsA case-cohort study was conducted. The written informed consent was obtained. Elective surgery adult patients undergoing general anaesthesia and tracheal intubation were recruited. The other inclusion criteria were: no maxillofacial deformity, trauma, airway stenosis, known difficult airway. The exclusion criteria were: tracheal intubations or operations were canceled, or patients’ data were missing. HMD ultrasound measurements of patients in a sniffing position and other usual airway evaluations were performed before general anaesthesia induction. The primary outcome was the intubation difficulty level. Predictive values were calculated. ResultsWe successfully enrolled 2357 patients (62 difficult intubation patients) in the cohort study for analysis. The area under the receiver operating characteristic curve (AUC) of the HMD and TMD for predicting difficult intubation was 0.86 (95% CI, 0.84−0.87) and 0.77 (95% CI, 0.75−0.78) respectively (comparison: P < 0.001). With an optimal cut-off value of HMD ≤ 4.9 cm, we observed a sensitivity and specificity of 0.90 (95% CI, 0.80−0.96) and 0.73 (95% CI, 0.71−0.75). Meanwhile, with TMD ≤ 7.0 cm, the sensitivity and specificity were 0.77 (95% CI, 0.65−0.87) and 0.65 (95% CI, 0.63−0.67) respectively. ConclusionIn comparison to TMD, HMD measured by ultrasound was more sensitive in predicting difficult intubation.

Positive Predictive Value of Upper Lip Bite Test in Predicting Difficult Intubation

Objective: To determine the positive predictive value of upper lip bite test in predicting difficult intubation by taking Cormack and Lehane classification as gold standard. Design of the Study: Cross sectional study. Study Settings: This cross-sectional study was conducted at Department of Anesthesiology, Sir Ganga Ram Hospital, Lahore from 04/06/2021 to 03/12/2021. Materials and Methods: This study involved 313 patients of both genders, aged between 18-70 years undergoing general anesthesia on elective lists having positive upper lip bite test (Grade-III). On the basis of Cormack and Lehane Classification, the diagnosis was verified. Results of the ULBT were compared to the Cormack and Lehane grade-III and grade-IV diagnoses. Every patient's written informed permission was obtained. Results: In The mean age of the patients was 43.78±12.32 years. Majority (n=150, 47.9%) of the patients were aged between 36-52 years. There were 198 (63.3%) male and 115 (36.7%) female patients in the study group. Among the procedures, herniorrhaphy (32.9%) and cholecystectomy (26.8%) were the more frequent procedures followed by thyroidectomy (17.6%), tonsillectomy (13.1%) and mastectomy (9.6%). Majority (42.8%) of the patients belonged to ASA Class-I followed by ASA Class-II (29.7%) and ASA Class-III (27.5%). Difficult intubation was confirmed in 232 (74.1%) patients on Cormack and Lehane Classification (as per operational definition). Thus there were 232 true positive patients with 81 false positive patients. With the gold standard Cormack and Lehane Classification, the upper lip bite test yielded a positive predictive value of 74.1 percent in the prediction of difficult intubation. Conclusion: According to the gold standard of Cormack and Lehane Classification, an upper lip bite test (Grade-III) has a 74.1 percent positive predictive value for difficult intubation in patients undergoing general anaesthesia with endotracheal intubation on the elective list. Keywords: Difficult Intubation, Cormack and Lehane Classification, Upper Lip Bite Test

Obstructive sleep apnea in surgical patients and its relationship with difficult intubation: two years of experience from a single center

Background and objectivesIn this study, we aimed to determine the risk of obstructive sleep apnea (OSA) in patients undergoing elective surgery and its relationship with difficult intubation (DI). MethodsThis prospective, descriptive, cross-sectional study was conducted between December 2018 and February 2020 in the anesthesiology and reanimation service of a training and research hospital. The study included patients who were ASA I...II, 18 years of age, and older who underwent elective surgery under general anesthesia. A form regarding the baseline characteristics of the participants as well as STOP-Bang score, Mallampati, and Cormack-Lehane classification was used to collect the data. ResultsThe study included 307 patients. It was determined that 64.2% of patients had a high risk of OSA. The presence of DI (determined by repeated attempts at intubation) was 28.6% in the high-risk OSA group, while there was no DI in the low-risk OSA group. A statistically significant difference was found between the groups in terms of OSA risk according to the presence of DI according to repeated attempts, Cormack-Lehane classification, and Mallampati classification (p...<...0.001). ConclusionDue to the high rate of DI in patients with a high risk of OSA, the security of the airway in these patients is endangered. Early clinical recognition of OSA can help in designing a safer care plan.

A Predictor of Difficult Airway: The Tasli Classification in Transnasal Flexible Laryngoscopy

IntroductionDifficult airway is defined as difficulty or failure in one or more steps in upper airway management. Evaluation of the upper airway with physical examination methods and endoscopic devices is crucial in predicting difficult airway. The aim of this study was to evaluate bedside tests, Cormack Lehane (CL) and Tasli Classification (TC) scores of the patients and it was aimed to reveal the role of TC which will be performed preoperatively as a predictor of difficult tracheal intubation (DTI). MethodsThe study included a total of 98 patients who underwent surgical treatment under general anesthesia. Demographic data, including age, gender, and body mass index (BMI), and bedside tests consisting Modified Mallampati Classification (MMC), thyromental (TD) and sternomental (SD) distances, neck circumference (NC), interincisor distance (IID), CL and TC were recorded. ResultsEvaluation was made of 64 (65.3%) male and 34 (34.7%) female patients ranging in age from 18 to 84 years (mean age: 50.35 ± 0.47 years). The successfully intubated patients (SIP) group comprised 68 (69.4%) patients, and the difficult intubation patients (DIP) group, 30 (30.6%). According to CL, the numbers of SIP and DIP constituting grade 1 was 29 (42.6%) and one (3.3%); grade 2a was 29 (42.6%) and one (3.3%); grade 2b was eight (11.8%) and three (10%); grade 3a was one (1.5%) and six (20%); grade 3b was one (1.5%) and 14 (46.7%) respectively. Grade 4 was only detected in the DIP group in 5 (16.7%) patients. According to TC, the numbers of SIP and DIP constituting grade 1 was 20 (29.4%) and 1 (3.3%); grade 2a was 37 (54.4%) and seven (23.3%); grade 2b was 10 (14.7%) and 18 (60%); grade 3 was one (1.5%) and two (6.7%) respectively. Grade 4 was only detected in the DIP group in two (6.7%) patients. ConclusionThe TC, CL, NC and BMI scores were higher in the DIP group and higher TC scores (grade 2b, 3, and 4) can be a predictor of difficult airway. However, it may be more beneficial to use TC as a complementary diagnostic tool with bedside tests such as NC, SM, TM and MMC, rather than used alone.

Incidence of Difficult Laryngoscopy in Adult Congenital Heart Disease Patients: A Retrospective Cohort Study

To identify the incidence of difficult intubation in patients with adult congenital heart disease (ACHD) undergoing cardiac surgery or catheterization. A retrospective cohort study. A single-center academic quaternary pediatric hospital. All patients were >18 years of age with ACHD undergoing endotracheal intubation within the Heart Center at Texas Children's Hospital between January 2012 and December 2019. None. A retrospective chart review was performed, including patient demographics, preoperative airway assessment and intraoperative airway management characteristics. Airways were categorized as difficult using the Pediatric Difficult Intubation registry operational definitions. For patients classified as having a difficult airway, the preoperative airway examination findings were recorded in addition to factors associated with difficult airway in the adult. The study authors identified 1,029 patients with ACHD who underwent procedures with anesthesia at their institution and were analyzed for the presence of difficult airway. In total, 878 patients were intubated, with 4.3% (n=38) identified to have difficult airway. The presence of concomitant syndromes was greater in patients with difficult intubations and those who were not intubated compared with those who were not difficult intubations (23.7% and 17.2 v 7.5; p < 0.001), respectively. Most patients did not have typical signs associated with difficult intubation. The study authors identified an incidence of difficult laryngoscopy in their cohort of ACHD patients to be 4.3%. Their incidences of difficult laryngoscopy were fewer than that reported in adult patients with noncongenital heart disease. Most importantly, the risk factors associated with difficult laryngoscopy in the normal adult may be different from those presenting with ACHD, necessitating further investigation.

Evaluation of super-obesity and super-super-obesity as risk factors for difficult intubation in patients undergoing bariatric surgery.

Super-obesity is a serious disorder which requires bariatric surgery. The association of super-obesity and difficult intubation was not adequately established. To determine if super-obesity and super-super-obesity are associated with difficult intubation or not. University Hospital. A cohort of obese patients scheduled for bariatric surgery was prospectively recruited. Super-obesity and super-super-obesity were defined as body mass index ≥50 kg/m2 and 60 kg/m2, respectively. Intubation difficulty was assessed by 2 methods: (1) intubation difficulty scale; (2) number of intubation attempts. Risk factors for difficult intubation were recorded. Univariate and multivariate analysis for risk factors for difficult intubation and difficult mask ventilation were performed. A total of 658 patients were enrolled in the study including 205 (31%) super-obese and 52 (8%) super-super-obese patients. Ninety-nine (15%) patients required more than 1 intubation attempt, while 215 (33%) patients had intubation difficulty scale ≥5. Ninety-four (14.4%) patients had mask ventilation of moderate difficulty, while only 2 (.3%) patients needed 2-person ventilation. The independent risk factors for difficult intubation using the two stated definitions were STOP-Bang and Mallampati score values. The independent risk factors for mask ventilation of moderate difficulty were STOP-Bang score, Mallampati score, and limited neck extension. Within obese patients, neither super-obesity nor super-super-obesity was associated with difficult intubation or difficult mask ventilation. High STOP-Bang and Mallampati score are the independent factors for difficult intubation.

A prospective observational study on predicting the risk of obstructive sleep apnea and difficult intubation in patients posted for elective surgery

Introduction: The present study compared video laryngoscope with Macintosh laryngoscope in terms of laryngoscopic time, total intubation time, Cormack and lehane scale and stress response while intubating. Materials and methods: After a standardized technique of induction of anesthesia, Group MCL (53 cases) intubated with Macintosh laryngoscope and Group VVL (53cases) intubated with Vividtrac Video laryngoscope. We compared laryngoscopic time, total intubation time, Cormack and lehane scale and stress response while intubating in these two groups. Results: The heart rate and blood pressure was above immediately after post intubation and started declining to reach post induction value at about three to five minutes in both groups (p values > 0.05).The mean tracheal intubation time was 11.05 seconds in MCL group and 18.05 seconds in VVL group (p-0.001). All cases in VVL group were intubated in first attempt, but one patient in MCL group required two attempts for success (p->0.05). Visualisation of glottis and non-alignment of the airway axis was better with VVL (p-0.001). There is no desaturation noted in all of the 106 cases. Conclusion: Vivid trac Laryngoscope has a comparable similar safety profile with Macintosh laryngoscope with respect to deleterious haemodynamic response produced by rigid manipulation of airway. Vivid trac Video Laryngoscope, a rigid channeled indirect laryngoscope provides always the better view of the laryngeal inlet than the Macintosh direct laryngoscope. Intubation time in Vividtrac video laryngoscopy was more than conventional laryngoscopy.

PREDICTION OF DIFFICULT INTUBATION BY USING UPPER LIP BITE, THYROMENTAL DISTANCE AND MALLAMPATI SCORE IN COMPARISON TO CORMACK AND LEHANE CLASSIFICATION SYSTEM

The aim: To evaluate efficacy of Modified Mallampati test (MMT), upper lip bite test (ULBT) and Thyromental distance (TMD) or combination of two method Modified Mallampati test (MMT)+ upper lip bite test (ULBT), Thyromental distance (TMD) + upper lip bite test (ULBT) in prediction of difficult intubation in patients undergoing GA. Materials and methods: Three tests were carried out in all patients by a single anesthesiologist. These were MMT, ULBT and TMD. Laryngoscopy was performed with patient’s head in the sniffing position. The laryngoscopy view was graded according to modified Cormack and Lehane classification system. Study was prospective, single cross sectional, in 151 adult patients who required GA with endotracheal intubation for elective surgery. On arrival in the operating room, routine monitoring and venous cannula were introduced. Midazolam, Fentanyl. and rocuronium, ketamine , propofol were given to facilitate endotracheal intubation. Results: Out of 150 assessed patients, 18 (12%) had difficult intubation. Of those 18 patients, 17 (83.33%) patients had Cormack and Lehane classification III and one patient (16.67%) had classification IV. Compared with Cormack and Lehane classification system as the gold standard for difficult intubation, the sensitivity and specificity of MMT was 66.67% and 96.97% respectively, while ULBT had a sensitivity of 77.78% and a specificity of 93.18%, and TMD had a sensitivity of 55.56% and specificity of 94.97% respectively. A combination of different tests improved their efficiencies. The sensitivity and specificity MMT and TMD combinations was 77.78% and 92.42% respectively, while it was 88.89% and 93.18%, respectively for MMT and ULPT. The combination of TMD and ULBT has a sensitivity of 88.33% and a specificity of 91.67%. Conclusions: Upper lip biting test has the best sensitivity while MMT had the best specificity. No single test alone can be reliable for predicting of difficult intubation. The combination of ULBT and MMT was the best in terms of both sensitivity and specificity for prediction of difficult intubation.

Effectiveness of four ultrasonographic parameters as predictors of difficult intubation in patients without anticipated difficult airway.

BackgroundPredicting difficult intubation (DI) is a key challenge, as no single clinical predictor is sufficiently valid to predict the outcome. We evaluated the effectiveness of four upper airway ultrasonographic parameters in predicting DI. The validity of the models using combinations of ultrasonography-based parameters was also investigated.MethodsThis prospective, observational, double-blinded cohort trial enrolled 1,043 surgical patients classified as American Society of Anesthesiologists physical status I–III without anticipated difficult airway. Preoperatively, their tongue thickness (TT), invisibility of hyoid bone (VH), and anterior neck soft tissue thickness from the skin to thyrohyoid membrane (ST) and hyoid bone (SH) were measured by sublingual and submandibular ultrasonography. The logistic regression, Youden index, and receiver operator characteristic analysis results were reported.ResultsOverall, 58 (5.6%) patients were classified as DI. The TT, SH, ST, and VH had accuracies of 78.4%, 85.0%, 84.7%, and 84.9%, respectively. The optimal values of TT, SH, and ST for predicting DI were > 5.8 cm (sensitivity: 84.5%, specificity: 78.1%, AUC: 0.880), > 1.4 cm (sensitivity: 81%, specificity: 85.2%, AUC: 0.898) and > 2.4 cm (sensitivity: 75.9%, specificity: 85.2%, AUC: 0.885) respectively. VH had a sensitivity and specificity of 72.4% and 85.6% (AUC: 0.790). The AUC values of the five models (with combinations of three or four parameters) ranged from 0.975–0.992. ST and VH had a significant impact on the individual models.ConclusionsSH had the best accuracy. Individual parameters showed limited validity. The model including all four parameters offered the best diagnostic value.

Airway management in bariatric surgery patients, our experience in Qatar: A prospective observational cohort study

Background: Obesity has always been considered a criterion of difficult airway management, and many authors have tackled this subject. We are presenting our experience in airway management in obese patients undergoing bariatric surgery in Qatar and comparing the results with previous studies. Objective: The primary objective of this study was to explore the relationship between difficult mask ventilation and difficult intubation. The secondary objective was to identify other factors that may play a role in either difficulty such as gender, associated comorbidities, and the skill and experience of anesthetists. Design: This study was a prospective observational cohort study. Sample: A total of 401 patients were selected for various elective bariatric surgery in Hamad General Hospital, including 130 males and 271 females with an average body mass index(BMI) of 46.03 kg m− 2. Results: We used Pearson Chi-Square and Yates corrected Chi-square statistical tests in our statistical analysis. Neck circumference had a p value of 0.001 in both genders. The male gender had a p value of 0.052 and 0.012 in mask ventilation and difficult intubation, respectively. The Mallampati score had a p value of 0.56 and 0.006 in mask ventilation and intubation, respectively. In general, neck circumference, Mallampati score, gender, obstructive sleep apnea, and diabetes mellitus had greater negative effects on airway management than BMI alone. Conclusion: It was hard to intubate 25% of patients who had difficult mask ventilation (DMV). All DMV and 20 out of 23 of difficult intubation patients were in the high BMI group ( ≥ 40). Neck circumference, Mallampati score, and male gender were major independent factors; however, other factors, such as obstructive sleep apnea, and diabetes mellitus, should be kept in mind as additional risks.

A new simple score for prediction of difficult laryngoscopy: the EL.GA+ score.

Preoperative airway assessment plays a key role in the context of difficult airway management. Several scores have been proposed to predict difficult intubation including the el-Ganzouri index (EL.GA). Anatomical parameters such as the opening of the mouth or the circumference of the neck (which currently is not usually evaluated) are used to predict difficult intubation. The nutritional status of super-morbid obesity (body mass index [BMI] > 50 kg m-2) is a recognised risk factor for difficult intubation. This is a single-centre, retrospective, observational study whose aim is to validate an additional parameter (anatomical plus nutritional) to the El.GA index, hence the choice of the acronym for the definition of the study: EL.GA+, in predictivity of airway management; multiple logistic regression analysis was performed to determine the predictive role of BMI, neck circumference and opening of the mouth of intubation difficulty measured with the gold standard. In total, 240 patients who had an elective surgical procedure under general anaesthesia, requiring endotracheal intubation, were examined. The predictive value of the EL.GA score was confirmed by the values of sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) according to the data reported in the literature. Furthermore, based on the values of the PPV and NPV (0.69 and 0.60 respectively), neck circumference of 42.5 cm can be taken as a cut-off value for which EL.GA+ becomes predictive of difficult intubation in patients with mild obesity (BMI of 30 to 35). The EL.GA+ score greatly increases the prediction of difficult laryngoscopy in mildly obese patients.

The predictive value of skin-to-epiglottis distance to assess difficult intubation in patients who undergo surgery under general anesthesia

Background: Intubation is crucial in the management of anesthesia because it is related to the maintenance of oxygenation and ventilation during general anesthesia. Clinical markers for predicting difficult airway have limitations, including requiring coordination with patients. The use of ultrasonography (USG) to measure the distance of the skin to epiglottis is expected to estimate the difficulty level of intubation. Patients and Methods: This was a cross-sectional study of 128 patients who underwent surgery under general anesthesia. We examined the skin-to-epiglottis distance using US prior to surgery. We then assessed the Cormack–Lehane scores during direct laryngoscopy for intubation. The unpaired t-test was used to assess differences in the skin-to-epiglottis distance between patients with easy intubation (Cormack–Lehane I and IIa) and difficult intubation (Cormack–Lehane IIb, III, and IV). Results: The cutoff value of skin-to-epiglottis distance between easy and difficult intubation was 26.05 mm. The sensitivity and specificity of this method to predict difficult airway were 69.4% and 93.5%, respectively. The positive and negative predictive values were 80.6% and 88.7%, respectively. Conclusion: The skin-to-epiglottis distance of >26.05 is a risk factor for difficult intubation.

Comparison of the Parker flex tip and the unoflex reinforced endotracheal tube for orotracheal fibreoptic intubation in simulated difficult intubation patients.

The choice of endotracheal tube (ETT) is important for successful orotracheal fibreoptic intubation (OFI). The aim of this study was to compare the use of the Parker flex tip (PFT) with the unoflex reinforced (UFR) ETT during OFI. A total of 58 patients who underwent elective surgery under general anaesthesia were randomised to two ETT groups, the PFT group (n = 29) and the UFR group (n = 29), for OFI in simulated difficult intubation patients using a rigid cervical collar. After successful standardised induction and relaxation, OFI and railroading of selected ETT were subsequently performed by a similarly experienced practitioner. Ease of insertion, degree of manipulation, time to successful intubation, post-intubation complications and haemodynamic changes were recorded for both groups. he percentage of easy intubation was comparable between both groups with a slightly higher percentage in the UFR group than the PFT group (69.0% vs. 62.0%; P = 0.599). Degree of manipulation was also comparable between the two groups; the percentage of cases in which manipulation was not required was slightly higher in the UFR group than the PFT group (69.0% vs. 62.1%; P = 0.849). Time to successful intubation was also comparable between the groups, although the time was slightly shorter for the UFR group than the PFT group (56.9 s ± 39.7 s vs. 63.9 s ± 36.9 s; P = 0.488). There were also no significant differences in other parameters. The Parker flex tip ETT was comparable to the unoflex reinforced ETT for OFI in simulated difficult airway patients.

Evaluation of difficult airway in paediatric population ranging from 5-12 years age group

Background: The aim of this study is to predict difficult airway on the basis of various airway assessment parameter in the paediatric population between 5-12 years age group. To assess the value of modified Mallampati test (MMT), upper-lip-bite test (ULBT), thyromental distance (TMD), ratio of height to thyromental distance (RHTMD) from which Cormack Lehane grade was derived to predict difficult airway i.e. difficult intubation in paediatric patients ranging from 5-12 years age. Material and Methods: 100 ASA grade I & II paediatric patients of either sex between the age group of 5-12 years posted for elective surgery under general anaesthesia requiring endotracheal intubation were included in the study. Modified Mallampati test, upper lip bite test, thyromental distance and ratio of height to thyromental distance of the patients were measured and recorded. All the distances were measured with the help of a flexible measuring tape so as to measure the distances accurately. Results: Modified Mallampati test has the highest sensitivity (75%) and specificity (92.05%) among all the other screening tests. It also has high positive predictive value (56.25%), negative predictive value (96.43%) and diagnostic accuracy (90%). Upper Lip Bite test has high specificity (79.55%) and negative predictive value (93.33%) with high diagnostic accuracy (77%). It has a sensitivity of 58.33% which is similar to the sensitivity of thyromental distance and ratio of height to thyromental distance. Thyromental distance has high specificity (65.90%) with high negative predictive value (92.06%). Conclusion: Modified Mallampati test is a useful bedside screening test for predicting difficult intubation in patients between 5-12 years age group. The Upper Lip bite test and thyromental distance has high specificity with high negative predictive value and diagnostic accuracy. The ratio of height to thyromental distance is least useful predictor of airway assessment.

Airway management in patients with mucopolysaccharidoses: The progression toward difficult intubation.

Patients with mucopolysaccharidoses (MPS) have physical changes to their airways over time. Due to the natural progression of their disease, these patients become more difficult to intubate as they get older. The aims of this study were to evaluate the difficulty of airway management in MPS patients over time, and to evaluate the effect of bone marrow transplant and/or enzyme replacement therapy on airway difficulty. A retrospective review of MPS patients presenting for surgery from January 2012 to May 2018 was performed. Patients were assigned to groups based on their ages at the time of surgery, number of intubation attempts, equipment used for intubation, difficulty of mask ventilation, and difficulty of laryngeal mask airway placement. The same designations were applied to patients with a history of a bone marrow transplant (BMT) and/or enzyme replacement therapy, and they were compared to patients of similar ages who had received no treatment. Logistic regression was used to determine the odds of difficult intubation. One hundred and twenty-eight anesthetic records were reviewed. In 27 cases, the patient had a BMT and in 54 cases, the patient had received enzyme replacement therapy. Adults (18years and older) had the highest likelihood of difficult intubation (OR 13.44, CI 1.45-124.86, P=0.022). Mask ventilation and laryngeal mask airway placement were not significantly more difficult in any age groups. Bone marrow transplant did not improve airway management. A history of enzyme replacement therapy was associated with an increased risk of difficult intubation in patients under the age of 12. As patients with MPS get older, there is a progression toward difficult intubation. Mask ventilation and laryngeal mask airway placement does not become more difficult with age. Bone marrow transplantation did not affect airway difficulty in our population, while enzyme replacement therapy was associated with difficult intubations in younger patients.

Difficult Intubation in Patients with Carcinoma of the Larynx and Hypopharynx

Introduction: ASA defines difficult intubation as tracheal intubation which requires more than three attempts with direct laryngoscopy. In a major study including 3325 patients, three or more attempts for direct laryngoscopy were needed in 1,9%, and intubation failure was observed in 0,1%. The Aim of the study is to determine difficult intubation rates in patients with laryngeal and hypopharyngeal carcinoma. Materials and Methods: A prospective cohort study including 100 patients undergoing microlaryngeal surgery in the Department of Otorhinolaryngology at the University Hospital „Queen Giovanna“ – ISUL, Sofia, in the period 2014-2017. Results and discussion: Difficult intubation is observed in 8 patients (8%). Impossible intubation is observed in 12 patients (12%). The study showed that the major factor leading to difficult endotracheal intubation in patients with carcinoma of the larynx and hypopharynx is the laryngeal obstruction caused by the malignant process. Conclusion: difficult and impossible intubation rates in patients undergoing laryngectomies are higher than in the common population due to the obstruction caused by the carcinoma.