Anticipation of the difficult airway: preoperative airway assessment, an educational and quality improvement tool

The Impact of Preoperative Flexible Fiberoptic Laryngoscopy on Anesthesia's Intubation Plans

Purpose: To assess the value of conducting a preairway management review of flexible fiberoptic laryngoscopy examinations (FFL) by the anesthesia team for patients with head and neck cancer and to examine its impact on intubation strategies and overall patient safety. Methods: Prospective study at a single tertiary referral center including patients with stage T2 and greater cancers of the oropharynx, hypopharynx, or larynx who underwent intubation by the anesthesia team between May 2022 and April 2023. Pre- and postoperative surveys gathered data on the intubation plan, including details such as method, sedation, patient respiration, laryngoscope, tube size, and use of paralysis. Postoperative surveys gauged the FFL's subjective utility and documented intubation details and complications. Results: Thirty-four patients (49-87 years of age) were included in the study. Eleven intubation plans were changed after reviewing the FFL, while 23 were not. Although this was a pilot study, there was no significant correlation between location of the tumor and change in intubation plan. Of the 34 intubations, 9 were executed based on the plan after reviewing FFL. The majority of the attending anesthesiologists agreed or strongly agreed that seeing the FFL was more helpful than reading the findings in clinic notes and that reviewing the FFL was helpful in creating the intubation plan, 77% and 88%, respectively. Conclusion: Reviewing the FFL led to changes in the anesthesia team's intubation plan in 32% of the cases in our pilot study. While these findings are promising, they highlight the need for further research with larger sample sizes and across multiple centers to validate the impact of FFL on intubation strategies for patients with stage T2 and greater cancers of the oropharynx, hypopharynx, or larynx.

Anaesthesia Management in a Case of Ludwig's Angina With Difficult Airway Managed by Emergency Tracheostomy

Severe neck infections present significant challenges for anesthesiologists due to the complexities associated with managing difficult airways. Ludwig's angina, a rapidly progressing infection of the submandibular space, exemplifies these challenges due to the high risk of airway obstruction. This case report details an emergency procedure performed to drain Ludwig's angina, highlighting the difficulties encountered and the strategies employed. Awake fiberoptic intubation is demonstrated as an effective approach for maintaining the airway during such operations. The report underscores the critical nature of quick and effective management, emphasizing the importance of readiness for interventions such as tracheostomy in cases where oxygen saturation drops, thereby ensuring patient safety in precarious situations.

A Prospective Study Evaluating Gender Differences of Serious Outcomes through Difficult Airway Physiological Score (DAPS) in the Emergency Department

Introduction

Gender variation in critically ill adults after resuscitation is reported in many studies. However, this variation is not well established when evaluating the physiological instability in this population. This study aimed to prospectively evaluate the gender variation in serious outcomes by the difficult airway physiological score (DAPS) among critically ill patients requiring endotracheal intubation (ETI).

Methods

This is a cohort study conducted from August 2021 to December 2022 in the emergency department of Aga Khan University. The prospective validity of the difficult airway physiological score was derived using retrospective data and includes 12 variables: sex, age, time of intubation, hypotension, respiratory distress, vomiting, shock index >0.9, pH < 7.3, fever, anticipated decline, Glasgow Coma Scale (GCS) < 15, and agitation. The serious outcomes were cardiac arrest, mortality (within 1 hour after intubation in emergency), hypotension (systolic blood pressure <90 mmHg), and oxygen desaturation (SpO2 < 92%). The difference between males and females was assessed using the chi-square test, and the association of gender and serious outcomes was explored using Cox and logistic regression analysis. ROC curve analysis and area under the curve assessed score validity separately in males and females with serious outcomes.

Results

We enrolled 326 patients with a mean age of 50.3 (±17.8), with 123 (33.7%) females and 203 (62.2%) males. 198 (60.7%) patients were >45 years old, of which 136 (67%) were male and 62 (50.4%) female. Cardiac arrest was observed in 56 (17.2%), with 24 (19.5%) females and 32 (15.8%) males, p value 0.348. Hypotension after intubation was observed in 132 (40.5%) patients, 56 (45.5%) females and 76 (37.4%) males, p value 0.149. Oxygen saturation (<92%) was observed in 80 (24.5%) patients, 32 (26%) females and 48 (23.6%) males, p value 0.630. In females, the DAPS of 11 had an area under the curve of 0.863 (0.74-0.91). The sensitivity of the score was 84.8%, the specificity was 71.9%, the PPV was 77.8%, and the NPV was 80.4% with an accuracy of 78.9%. In males, the DAPS score of 14 had an area under the curve of 0.892 (0.57-0.75). The sensitivity of the score was 67%, the specificity 93.8%, the PPV 92.2%, and the NPV 72.2% with an accuracy of 79.8%.

Conclusions

The Difficult Airway Physiological Score (DAPS) predicts the risk of serious outcomes after intubation with high precision and reliability with different score cutoffs between the two sexes, highlighting the gender variation of a difficult airway.

Quality Improvement Projects and Anesthesiology Graduate Medical Education: A Systematic Review

Quality improvement (QI) projects are essential components of graduate medical education and healthcare organizations to improve patient outcomes. We systematically reviewed the literature on QI projects in anesthesiology graduate medical education programs to assess whether these projects are leading to publications. A literature search was conducted in July 2023, using PubMed, Embase, and the Central Register of Controlled Trials (CENTRAL) for articles describing QI initiatives originating within the United States and applicable to anesthesiology residency training programs. The following data were collected: intervention(s), sample size (number of participants or events), outcome metric(s), result(s), and conclusion(s). One hundred and fifty publications were identified, and 31 articles met the inclusion criteria. A total of 2,259 residents and 72,889 events were included in this review. Educational modalities, such as simulation, training sessions, or online curricula, were the most prevalent interventions in the included studies. Pre-intervention and post-intervention assessments were the most common outcome metrics reported. Our review of the literature demonstrates that few QI projects performed within anesthesiology training programs lead to published manuscripts. Further research should aim at increasing the impact of required QI projects within the sponsoring institution and specialty.

Development and validation of a regression model with nomogram for difficult video laryngoscopy in Chinese population: a prospective, single-center, and nested case-control study

Background

Airway management failure is associated with increased perioperative morbidity and mortality. Airway-related complications can be significantly reduced if difficult laryngoscopy is predicted with high accuracy. Currently, there are no large-sample studies on difficult airway assessments in Chinese populations. An airway assessment model based on the Chinese population is urgently needed to guide airway rescue strategy.

Methods

This prospective nested case-control study took place in a tertiary hospital in Shanghai, China. Information on 10,549 patients was collected, and 8,375 patients were enrolled, including 7,676 patients who underwent successful laryngoscopy and 699 patients who underwent difficult laryngoscopy. The baseline characteristics, medical history, and bedside examinations were included as predictor variables. Laryngoscopy was defined as 'successful laryngoscopy' based on a Cormack-Lehane Grades of 1-2 and as 'difficult laryngoscopy' based on a Cormack-Lehane Grades of 3-4. A model was developed by incorporating risk factors and was presented in the form of a nomogram by univariate logistic regression, least absolute shrinkage and selection operator, and stepwise logistic regression. The main outcome measures were area under the curve (AUC), sensitivity, and specificity of the predictive model.

Result

The AUC value of the prediction model was 0.807 (95% confidence interval [CI]: 0.787-0.828), with a sensitivity of 0.730 (95% CI, 0.690-0.769) and a specificity of 0.730 (95% CI, 0.718-0.742) in the training set. The AUC value of the prediction model was 0.829 (95% CI, 0.800-0.857), with a sensitivity of 0.784 (95% CI, 0.73-0.838) and a specificity of 0.722 (95% CI, 0.704-0.740) in the validation set.

Conclusion

Our model had accurate predictive performance, good clinical utility, and good robustness for difficult laryngoscopy in the Chinese population.

Anesthesia and Enhanced Recovery After Surgery in Bariatric Surgery

The Enhanced Recovery After Surgery Society published guidelines for bariatric surgery reviewing the evidence and providing specific care recommendations. These guidelines emphasize preoperative nutrition, multimodal analgesia, postoperative nausea and vomiting prophylaxis, anesthetic technique, nutrition, and mobilization. Several studies have since evaluated these pathways, showing them to be safe and effective at decreasing hospital length of stay and postoperative nausea and vomiting. This article emphasizes anesthetic management in the perioperative period and outlines future directions, including the application of Enhanced Recovery After Surgery principles in patients with extreme obesity, diabetes, and metabolic disease and standardization of the pathways to decrease heterogeneity.

Airway Abnormalities in Adult Mucopolysaccharidosis and Development of Salford Mucopolysaccharidosis Airway Score

(1) Background: Mucopolysaccharidoses (MPS) are a heterogeneous group of lysosomal storage disorders caused by the absence of enzymes required for degradation of glycosaminoglycans (GAGs). GAGs deposition in tissues leads to progressive airway narrowing and/or tortuosity. Increased longevity of patients has posed newer problems, especially the airway. This study aims to characterise various airway abnormalities in adult MPS from a regional centre and proposes a method to quantify the severity of the airway disease. (2) Methods: Retrospective analysis by case notes review, clinical examination, endoscopy, cross-sectional imaging, 3-dimensional reconstruction, and physiological investigations were used to assess the airway abnormalities. Quantitative assessment of the airway severity was performed a validated questionnaire of 15 parameters to derive Salford Mucopolysaccharidosis Airway Score (SMAS). (3) Results: Thirty-one adult MPS patients (21M/ 9F; median 26.7 years; range 19–42 years) were reviewed. There were 9 MPS I, 12 MPS II, 2 MPS III, 5 MPS IV, 2 MPS VI, and 1 MPS VII. Airway abnormalities in each MPS type are described. Patients scoring more than 35 on SMAS had some form of airway intervention. The area under curve of 0.9 was noted at a score of 25, so SMAS more than 25 may predict a difficult airway and potential to have complications. Pearson’s correlation between SMAS and height, weight, BMI were poor (p < 0.05). (4) Conclusions: Airway abnormalities in adult MPS are varied and complex. Assessment of the airway should be holistic and include multiple parameters. An objective multidimensional score such as SMAS may help to predict and manage difficult airways warranting further investigation and validation.

A new approach to airway assessment-"Line of Sight" and more. Recommendations of the Task Force of Airway Management Foundation (AMF)

Assessment of airway is recommended by every airway guideline to ensure safe airway management. Numerous unifactorial and multifactorial tests have been used for airway assessment over the years. However, there is none that can identify all the difficult airways. The reasons for the inadequacy of these methods of airway assessment might be their dependence on difficult to remember and apply mnemonics and scores, inability to identify all the variations from the “normal”, and their lack of stress on evaluating the non-patient factors. Airway Management Foundation (AMF) experts and members have been using a different approach, the AMF Approach, to overcome these problems inherent to most available models of airway assessment. This approach suggests a three-step model of airway assessment. The airway manager first makes the assessment of the patient through focused history, focused general examination, and focused airway assessment using the AMF “line of sight” method. The AMF “line of sight” method is a non-mnemonic, non-score-based method of airway assessment wherein the airway manager examines the airway along the line of sight as it moves over the airway and notes down all the variations from the normal. Assessment of non-patient factors follows next and finally there is assimilation of all the information to help identify the available, difficult, and impossible areas of the airway management. The AMF approach is not merely intubation centric but also focuses on all other methods of securing airway and maintaining oxygenation. Airway assessment in the presence of contagion like COVID-19 is also discussed.

Apnoeic oxygenation was associated with decreased desaturation rates during rapid sequence intubation in multiple Australian and New Zealand emergency departments

Apnoeic oxygenation (ApOx) has been demonstrated to reduce the incidence of desaturation, although evidence of benefit has been conflicting depending on the technique used. The aim of this study was to compare the incidence of desaturation between patients who received ApOx via conventional nasal cannula (NC) and those who did not, using a large, multicentre airway registry.

METHODS

This study is an analysis of 24 months of prospectively collected data in the Australia and New Zealand Emergency Department Airway Registry (June 2013-June 2015). The registry includes information on all intubated adults from 43 emergency departments. Patients intubated during cardiac arrest (n=393), those who received active ventilation prior to the first intubation attempt (n=486), and where the use of ApOx was not recorded either way (n=312) were excluded. The proportion of patients who desaturated (Sa0₂ <93) in the group that received ApOx and those that did not were compared. To evaluate the association of ApOx with patient desaturation, a logistic regression model based on factors expected to influence desaturation was performed.

RESULTS

Of 2519 patients analysed, 1669 (66.3%) received ApOx via NC while 850 (33.7%) did not. Desaturation in the cohort receiving ApOx was 10.4% compared with standard care (no ApOx) 13.7%. ApOx had a protective effect for desaturation (OR 0.71 95% CI 0.53 to 0.95). Single intubation attempt was associated with reduced risk of desaturation of (OR 0.10, 95% CI 0.06 to 0.17); this was increased on second attempt (OR 0.37, 95% CI 0.21 to 0.68). Desaturation was also associated with the physician recording that they had anticipated a difficult airway (OR 1.83, 95% CI 1.34 to 2.48).

CONCLUSION

This large multicentre registry study provides evidence that ApOx delivered through a conventional NC is associated with a lower incidence of desaturation in patients undergoing rapid sequence intubation.

TRIAL REGISTRATION NUMBER

ACTRN12613001052729.

Recommendations for the evaluation and management of the anticipated and non-anticipated difficult airway of the Societat Catalana d'Anestesiologia, Reanimació i Terapèutica del Dolor, based on the adaptation of clinical practice guidelines and expert consensus

The Airway Division of the Catalan Society of Anaesthesiology, Intensive Care and Pain Management (SCARTD) presents its latest guidelines for the evaluation and management of the difficult airway. This update includes the technical advances and changes observed in clinical practice since publication of the first edition of the guidelines in 2008. The recommendations were defined by a consensus of experts from the 19 participating hospitals, and were adapted from 5 recently published international guidelines following an in-depth analysis and systematic comparison of their recommendations. The final document was sent to the members of SCARTD for evaluation, and was reviewed by 11 independent experts. The recommendations, therefore, are supported by the latest scientific evidence and endorsed by professionals in the field. This edition develops the definition of the difficult airway, including all airway management techniques, and places emphasis on evaluating and classifying the airway into 3 categories according to the anticipated degree of difficulty and additional safety considerations in order to plan the management strategy. Pre-management planning, in terms of preparing patients and resources and optimising communication and interaction between all professionals involved, plays a pivotal role in all the scenarios addressed. The guidelines reflect the increased presence of video laryngoscopes and second-generation devices in our setting, and promotes their routine use in intubation and their prompt use in cases of unanticipated difficult airway. They also address the increased use of ultrasound imaging as an aid to evaluation and decision-making. New scenarios have also been included, such as the risk of bronchoaspiration and difficult extubation Finally, the document outlines the training and continuing professional development programmes required to guarantee effective and safe implementation of the guidelines.

Predictors of difficult airway in the obese are closely related to safe apnea time!

Background and Aims:

We aimed to redefine the preoperative factors that may challenge the airway and safe apnea time (SAT) in the obese.

Material and Methods:

We analyzed 834 patients with body mass index (BMI) >35 kg/m² for their difficult airway score (DASc). DASc is a consolidation of measures of difficult airway like mask ventilation, difficult intubation, change of device, and number of personnel required. DASc varied from “0” no difficulty to “12” serious difficulty and DASc ≥6 was considered difficult. Preoperative parameters – neck circumference (NC), BMI, STOPBANG score, Mallampati score, obstructive sleep apnea grade, and waist circumference– were assessed.

Results:

Receiver operating characteristic curve was used to identify risk factors for obese patients at DASc ≥6. The Youden index (for the best threshold, with highest sensitivity and specificity) was BMI 45 kg/m² and NC 44.5 cm. Their absence had an 81% negative predictive value to include a difficult airway, while their presence had a positive predictive value of 55%. This further has sensitivity of 66% and specificity of 73%. The mean SAT (256 ± 6 s) was inversely related to DASc (P < 0.001).

Conclusion:

This study demonstrates that BMI and NC have a strong association with difficult airway in obese patients and are inversely related to SAT. Amongst these NC is the single most important predictor of difficult airway in obese and should be used as a screening tool.

Ultrasonography for predicting a difficult laryngoscopy. Getting closer

Our objective was to evaluate the usefulness of five ultrasound measurements to predict a difficult laryngoscopy (DL). Prospective observational study. 50 patients underwent scheduled surgery under general anesthesia with orotracheal intubation with classical laryngoscopy at the University Hospital of Jaén (Spain). Sociodemographic variables, classic preintubation screening tests and ultrasound measurements of the neck soft tissue from skin to hyoid (DSH), epiglottis (DSE) and glottis (DSG) were obtained, as well as two measurements derived from the above: DSH + DSE and DSE - DSG. The relationship between a DL and ultrasound measurements was evaluated using t student test. The ROC Curve was used to establish the diagnostic accuracy of ultrasound measurements to discriminate a DL and logistic regression was used to establish a cut-off point. Multivariate analysis was performed to assess the impact of these measures in clinical practice. Patients with DL showed greater thickness of DSE (2.9 ± 0.46 cm vs 2.32 ± 0.54 cm; p = 0.001), DSH + DSE (4.25 ± 0.45 cm vs 3.62 ± 0.77 cm; p = 0.001) and DSE - DSG (1.83 ± 0.54 cm vs 1.24 ± 0.46 cm; p = 0.001) than those with an easy laryngoscopy. DSE and DSE - DSG had the highest diagnostic accuracy for DL with an area under the ROC curve of 0.79 [95%IC 0.66-0.92] and 0.82 [95%IC 0.68-0.96], respectively. It was established that DSE ≥ 3 cm, could predict a DL with a positive predictive value (PPV) of 69.23% [95%CI 40.3-98.2], and DSE - DSG ≥ 1.9 cm would do so with a PPV of 78.57% [95%CI 53.31-100%]. The multivariate analysis endorsed that DSE and DSE - DSG combined with classic tests (the Modified Mallampati score, the thyromental distance and the upper lip bite test) improved the preoperative detection of a DL. The inclusion of DSE and DSE - DSG in a multivariate model with classic parameters may offer the anesthesiologist better information for detecting a DL preoperatively.

Clinical Audit on the Practice of Documentation at Preanesthetic Evaluation in a Specialized University Hospital

Background:

Performing preanesthetic evaluation, documenting, and keeping readily accessible record are responsibilities of anesthetists. Documentation can improve overall patient outcome. It also has an irreplaceable role in medico-legal aspects. Documentation is one of the challenges of providing quality care.

Aim:

The aim of this study was to evaluate the quality of documentation practice during preanesthetic visits.

Materials and Methods:

This clinical audit was conducted in the University of Gondar Hospital. Predefined 22 practice quality indicators were prepared according to modified global quality index.

Statistical Analysis:

Descriptive statistics was performed using SPSS version 20.

Results:

A total of 122 preanesthetic evaluation tools (PAETs) were reviewed. None of PAETs found fully completed according to the indicators. Trends differ between elective and emergency conditions. Indicators with high completion rate (>90%) were signed a consent, medical history, history of medication, allergy, anesthesia and surgery, cardiopulmonary examination, airway examination, preoperative diagnosis, and planned procedure. Anesthetic plan, vital signs, a name, per-oral status, premedication, and age were found with below average (<50%) completion rate.

Conclusions:

Documentation practice during the preanesthetic visit was below the standard. Unclear instructions should be replaced with standardized contents. Providing regular trainings on clinical documentation for students and staffs, and introducing modern electronic-based documentation system and preanesthetic clinics may improve the practice.

The supraglottic airway device as first line of management in anticipated difficult mask ventilation in the morbidly obese

Background and Aims:

Supraglottic airway devices (SGAs) are used to rescue difficult and failed mask ventilation (DMV). We aimed to use the SGA as first-line device, prior to obtaining a definitive airway and to find any predictors of difficulty for the same, in the morbidly obese patients.

Material and Methods:

Obese surgical patients [body mass index (BMI) >35 kg/m²] were investigated. Difficulties with bag mask ventilation (MV) was graded using the following scale: MV-1, one anesthesiologist unassisted could achieve MV and maintain SpO₂>90%; MV-2, one additional anesthesiologist was needed to facilitate MV to achieve SpO₂> 90%; MV-3, two additional anesthesiologists were needed for this purpose; and MV-3P, when a supraglottic device was required to ventilate and maintain SpO₂ more than 90%. Parameters studied were age, gender, neck circumference (NC), BMI, STOPBANG score, and safe apnea time (SAT).

Results:

Logistic regression was performed for predictors of MV-3P; receiver operating characteristic curve was used to locate the best cut-off. Analysis of 834 morbidly obese patients revealed an incidence of MV 1/2/3/3-P as 16%/38%/27%/19%, respectively. DMV was associated with BMI ≥50 kg/m², NC ≥49.5 cm, and STOPBANG ≥6; P < 0.001. The mean SAT for a population with mean BMI 48 ± 8 kg/m² was 256 ± 66 s. The SAT showed inverse relation to BMI and NC. As per our results, the NC was the single most important predictor of MV-3P, with sensitivity 0.62 and specificity 0.85 at best cut-off 49.5 cm; P < 0.001.

Conclusion:

NC ≥49.5 cm is strongly associated with low SAT and need for SGA to achieve MV. SGA may provide safety for initial management following induction of anesthesia in this patient population.

Difficult laryngoscopy and tracheal intubation: observational study

Introduction

Since anesthesia complications associated with unexpected difficult airway are potentially catastrophic, they should be avoided. The modified Mallampati test and jaw-thrust maneuver enable the identification of difficult airway. The aim of this study was to associate the modified Mallampati test and the jaw-thrust maneuver with laryngoscopy (Cormack–Lehane) in an attempt to identify a better predictor of difficult airway in an adult population undergoing elective surgery.

Method

A cross-sectional study in which 133 adult patients undergoing elective surgery requiring tracheal intubation were analyzed. The accuracy and specificity of the modified Mallampati test and jaw-thrust maneuver were assessed by correlating them with difficult laryngoscopy (Cormack–Lehane Degrees 3 and 4).

Results

In the 133 patients evaluated the difficult intubation rate found was 0.8%; there was association between the two predictive tests proposed (p = 0.012). The values of 94.5% for specificity and 95.4% for accuracy were found for the jaw-thrust maneuver and for the modified Mallampati test, the values found were 81.1% and 81.2%, respectively. Kappa agreement identified a result of 0.240 between jaw-thrust maneuver and Cormack–Lehane, which was considered reasonable. On the other hand, a poor agreement (κ = 0.06) was seen between modified Mallampati test and Cormack–Lehane test.

Conclusion

The jaw-thrust maneuver presented superior accuracy and agreement than the modified Mallampati test, showing the ability to identify a difficult airway. It is necessary to emphasize the association of tests in the evaluation of patients, emphasizing their complementarity to minimize the negative consequences of repeated laryngoscopies.

[Difficult laryngoscopy and tracheal intubation: observational study]

INTRODUCTION

Since anesthesia complications associated with unexpected difficult airway are potentially catastrophic, they should be avoided. The modified Mallampati test and jaw-thrust maneuver enable the identification of difficult airway. The aim of this study was to associate the modified Mallampati test and the jaw-thrust maneuver with laryngoscopy (Cormack-Lehane) in an attempt to identify a better predictor of difficult airway in an adult population undergoing elective surgery.

METHOD

A cross-sectional study in which 133 adult patients undergoing elective surgery requiring tracheal intubation were analyzed. The accuracy and specificity of the modified Mallampati test and jaw-thrust maneuver were assessed by correlating them with difficult laryngoscopy (Cormack-Lehane Degrees 3 and 4).

RESULTS

In the 133 patients evaluated the difficult intubation rate found was 0.8%; there was association between the two predictive tests proposed (p=0.012). The values of 94.5% for specificity and 95.4% for accuracy were found for the jaw-thrust maneuver and for the modified Mallampati test, the values found were 81.1% and 81.2%, respectively. Kappa agreement identified a result of 0.240 between jaw-thrust maneuver and Cormarck-Lehane, which was considered reasonable. On the other hand, a poor agreement (κ=0.06) was seen between modified Mallampati test and Cormarck-Lehane test.

CONCLUSION

The jaw-thrust maneuver presented superior accuracy and agreement than the modified Mallampati test, showing the ability to identify a difficult airway. It is necessary to emphasize the association of tests in the evaluation of patients, emphasizing their complementarity to minimize the negative consequences of repeated laryngoscopies.

Guidelines for Perioperative Care in Bariatric Surgery: Enhanced Recovery After Surgery (ERAS) Society Recommendations

BACKGROUND

During the last two decades, an increasing number of bariatric surgical procedures have been performed worldwide. There is no consensus regarding optimal perioperative care in bariatric surgery. This review aims to present such a consensus and to provide graded recommendations for elements in an evidence-based "enhanced" perioperative protocol.

METHODS

The English-language literature between January 1966 and January 2015 was searched, with particular attention paid to meta-analyses, randomised controlled trials and large prospective cohort studies. Selected studies were examined, reviewed and graded. After critical appraisal of these studies, the group of authors reached a consensus recommendation.

RESULTS

Although for some elements, recommendations are extrapolated from non-bariatric settings (mainly colorectal), most recommendations are based on good-quality trials or meta-analyses of good-quality trials.

CONCLUSIONS

A comprehensive evidence-based consensus was reached and is presented in this review by the enhanced recovery after surgery (ERAS) Society. The guidelines were endorsed by the International Association for Surgical Metabolism and Nutrition (IASMEN) and based on the evidence available in the literature for each of the elements of the multimodal perioperative care pathway for patients undergoing bariatric surgery.

Clinical Experiences with the FRONT Formula for Pre-Operative Airway Assessment and Documentation: a Multi-Centre Study

OBJECTIVE

The prediction of difficult airway is one of the most important challenges before general anaesthesia. This study aimed to assess the clinical usefulness of the FRONT score, a recently developed scoring system to predict and document airway difficulties.

METHODS

This multi-centre, inter-observer, prospective and double-blinded study included 976 patients from two university centres. The pre-operative evaluation of the patients was performed by a pre-operative team of anaesthesiologists (team A) who evaluated and scored the expected difficulty of airway management. An intra-operative team of evaluators (team B) working independently of team A, performed the actual instrumentation of the airway and scored the actual findings. Both teams used the FRONT scoring system and worked independently of each other to ensure blinded assessments. The statistical analysis of the pre- and intra-operative FRONT scores was performed in an off-line blinded manner.

RESULTS

Our results show a fair and promising association between pre-operative composite FRONT score and that observed at the induction phase (Spearman=0.43). Among the score components, the best correlation was observed for the F and R components (kappa=0.44 and 0.36, respectively), and the worse correlation was observed for the O and T components (kappa=0.25 and 0.24, respectively).

CONCLUSION

The FRONT formula for the prediction and documentation of the airway status is a simple and effective method for assessing and defining airway management difficulties. Further prospective studies are required to assess the sensitivity and specificity of the system.

Assessing anesthesiology residents' out-of-the-operating-room (OOOR) emergent airway management

BACKGROUND

At many academic institutions, anesthesiology residents are responsible for managing emergent intubations outside of the operating room (OOOR), with complications estimated to be as high as 39%. In order to create an OOOR training curriculum, we evaluated residents' familiarity with the content and correct adherence to the American Society of Anesthesiologists' Difficult Airway Algorithm (ASA DAA).

METHODS

Residents completed a pre-simulation multiple-choice survey measuring their understanding and use of the DAA. Residents then managed an emergent, difficult OOOR intubation in the simulation center, where two trained reviewers assessed performance using checklists. Post-simulation, the residents completed a survey rating their behaviors during the simulation. The primary outcome was comprehension and adherence to the DAA as assessed by survey responses and behavior in the simulation.

RESULTS

Sixty-three residents completed both surveys and the simulation. Post-survey responses indicated a shift toward decreased self-perceived familiarity with the DAA content compared to pre-survey responses. During the simulation, 22 (35%) residents were unsuccessful with intubation. Of these, 46% placed an LMA and 46% prepared for cricothyroidotomy. Nineteen residents did not attempt intubation. Of these, only 31% considered LMA placement, and 26% initiated cricothyroidotomy.

CONCLUSIONS

Many anesthesiology residency training programs permit resident autonomy in managing emergent intubations OOOR. Residents self-reported familiarity with the content of and adherence to the DAA was higher than that observed during the simulation. Curriculum focused on comprehension of the DAA, as well as improving communication with higher-level physicians and specialists, may improve outcomes during OOORs.

Prediction of difficult laryngoscopy using spirometry: a pilot study

Prediction of difficult laryngoscopy is still the uncovered secret of anesthetic practice. This pilot study is aimed to assess the efficacy of spirometry measurements in predicting difficult laryngoscopy compared with conventional airway assessment techniques. We enrolled 202 adults, ages 18-40 years, with an American Society of Anaesthesiologists score of I or II, scheduled for elective surgery and undergoing general anesthesia. Spirometry was used for lung capacity measurements before the operation. The Mallampati classification, neck circumference, sternomental distance, thyromental distance, maximum mouth-opening measurement, and upper lip bite test of the subjects were measured. During intubation, the Cormack-Lehane grade was recorded. Spearman's correlation analysis was used to define the linearity between spirometry outputs and airway measurements. Receiver operating curves were drawn to discriminate the predictive features of the significant values. The thyromental distance showed a higher correlation with forced inspiratory vital capacity (ρ = 0.420, P < 0.001). In a multivariate linear regression model, all spirometry measurements revealed that forced inspiratory vital capacity (β = -2.050, P = 0.022) was the significant predictor for difficult laryngoscopy. The area under the curve for forced inspiratory vital capacity with a cut-off value of 3.1950 L while using thyromental distance as difficult laryngoscopy indicator is 0.754 and forced inspiratory vital capacity showed a sensitivity of 0.718 and specificity of 0.714 with a positive likelihood ratio of 2.5104 and negative likelihood ratio of 0.3949. Forced inspiratory vital capacity showed a close association with the prediction of difficult laryngoscopy.

[Post analysis simulated correlation of the El-Ganzouri airway difficulty score with difficult airway]

BACKGROUND

Difficult airway (DA) occurs frequently (5-15%) in clinical practice. The El-Ganzouri Risk Index (EGRI) has a high sensitivity for predicting a difficult intubation (DI). However difficult mask ventilation (DMV) was never included in the EGRI. Since DMV was not included in the EGRI assessment, and obstructive sleep apnea (OSA) is also correlated with DMV, a study correlating the prediction of DA and OSA (identified by STOP-Bang questionnaire, SB) seemed important.

METHODS

We accessed a database previously collected for a post analysis simulation of the airway difficulty predictivity of the EGRI, associated with normal and difficult airway, particularly DMV. As secondary aim, we measured the correlation between the SB prediction system and DA, compared to the EGRI.

RESULTS

A total of 2747 patients were included in the study. The proportion of patients with DI was 14.7% (95% CI 13.4-16) and the proportion of patients with DMV was 3.42% (95% CI 2.7-4.1). The incidence of DMV combined with DI was (2.3%). The optimal cutoff value of EGRI was 3. EGRI registered also an higher ability to predict DMV (AUC=0.76 (95% CI 0.71-0.81)). Adding the SB variables in the logistic model, the AUC increases with the inclusion of "observed apnea" variable (0.83 vs. 0.81, p=0.03). The area under the ROC curve for the patients with DI and DMV was 0.77 (95% CI 0.72-0.83).

CONCLUSIONS

This study confirms that the incidence of DA is not negligible and suggests the use of the EGRI as simple bedside predictive score to improve patient safety.

Facial Image Analysis for Fully Automatic Prediction of Difficult Endotracheal Intubation

GOAL

Difficult tracheal intubation is a major cause of anesthesia-related injuries with potential life threatening complications. Detection and anticipation of difficult airway in the preoperative period is, thus, crucial for the patients' safety. We propose an automatic face-analysis approach to detect morphological traits related to difficult intubation and improve its prediction.

METHODS

For this purpose, we have collected a database of 970 patients including photos, videos, and ground truth data. Specific statistical face models have been learned using the faces in our database providing an automated parametrization of the facial morphology. The most discriminative morphological features are selected through the importance ranking provided by the random forest algorithm. The random forest approach has also been used to train a classifier on these selected features. We compare a threshold tuning method based on class prior with two methods, which learn an optimal threshold on a training set for tackling the inherent imbalanced nature of the database.

RESULTS

Our fully automated method achieves an AUC of 81.0% in a simplified experimental setup, where only easy and difficult patients are considered. A further validation on the entire database has proven that our method is applicable for real-world difficult intubation prediction, with AUC = 77.9%.

CONCLUSION

The system performance is in line with the state-of-the-art medical diagnosis, based on ratings provided by trained anesthesiologists, whose assessment is guided by an extensive set of criteria.

SIGNIFICANCE

We present the first completely automatic and noninvasive difficult intubation detection system that is suitable for use in clinical settings.

Comparison of McGrath Series 3 and Macintosh Laryngoscopes for Tracheal Intubation in Patients With Normal Airway by Inexperienced Anesthetists: A Randomized Study

Difficult and failed intubations account for the major causes of morbidity and mortality in current anesthetic practice. Several devices including McGrath Series 3 videolaryngoscope are available which may facilitate tracheal intubation by improving view of the larynx compared with Macintosh blade laryngoscopy. But no studies demonstrate whether McGrath Series 3 performs better than Macintosh laryngoscope in normal airway intubations by inexperienced anesthetists so far. We therefore designed this randomized controlled study to compare McGrath with Macintosh in routine tracheal intubation performed by inexperienced anesthetists.In total, 180 adult patients with normal-appearing airways requiring orotracheal intubation for elective surgery were randomly allocated to be intubated by 9 inexperienced anesthetists with McGrath or Macintosh. The primary outcome was time to intubation. Ease of intubation was assessed by a 5-point ordinal scale. Intubation attempts/failures, best laryngoscopy view using the Cormack-Lehane grade, associated complications and hemodynamic changes during intubation were recorded.We found that there was no significant difference between McGrath and Macintosh in the median time to intubation (P = 0.46); the Cormack-Lehane views attained using McGrath were superior (P < 0.001); the difference of ease of intubation was statistically significant (P = 0.01). No serious trauma occurred in both groups. And there was statistically significant difference in the systolic blood pressure changes between 2 groups (P < 0.05).We demonstrated that in orotracheal intubation in patients with normal airway by inexperienced anesthetists, McGrath compared with the Macintosh allows superior glottis views, greater ease of intubation, less complications, and hemodynamic changes with noninferior intubation time. And it remained a potential selection for inexperienced anesthetists in uncomplicated intubation.

Live animals for preclinical medical student surgical training

AIMS

The use of live animals for surgical training is a well-known, deliberated topic. However, medical students who use live animals rate the experience high not only in improving their surgical techniques, but also positively influencing their confidence levels in the operating room later in their careers. Therefore, we hypothesized that the use of live animal models is a unique and influential component of preclinical medical education.

MATERIALS AND METHODS

Medical student performed the following surgical procedures using mice; surgical orthotopic implantation of cancer cells into fat pad and subsequently a radical mastectomy. The improvement of skill was then analyzed.

RESULTS

All cancer cell inoculations were performed successfully. Improvement of surgical skills during the radical mastectomy procedure was documented in all parameters. All wounds healed without breakdown or dehiscence. The appropriate interval between interrupted sutures was ascertained after fifth wound closure. The speed of interrupted sutures was doubled by last wound closure. The time required to complete a radical mastectomy decreased by almost half. A single animal died immediately following the operation due to inappropriate anesthesia, which was attributed to the lack of understanding of the overall operative management.

CONCLUSION

Surgical training using live animals for preclinical medical students provides a unique learning experience, not only in improving surgical skills but also and arguably most importantly, to introduce the student to the complexities of the perioperative environment in a way that most closely resembles the stress and responsibility that the operating room demands.

Laryngeal mask placement in a teaching institution: analysis of difficult placements

Background: Laryngeal mask airway (LMA) placement is now considered a common airway management practice. Although there are many studies which focus on various airway techniques, research regarding difficult LMA placement is limited, particularly for anesthesiologist trainees. In our retrospective analysis we tried to identify predictive factors of difficult LMA placement in an academic training program.

Methods: This retrospective analysis was derived from a research airway database, where data were collected prospectively at the Memorial Hermann Hospital, Texas Medical Center, Houston, TX, USA, from 2008 to 2010. All non-obstetric adult patients presenting for elective surgery requiring general anesthesia, were enrolled in this study: anesthesiology residents primarily managed the airways. The level of difficulty, number of attempts, and type of the extraglottic device placement were retrieved.

Results: Sixty-nine unique Laryngeal Mask Airways (uLMAs) were utilized as a primary airway device. Two independent predictors for difficult LMA placement were identified: gender and neck circumference. The sensitivity for one factor is 87.5% with a specificity of 50%. However with two risk factors, the specificity increases to the level of 93% and the sensitivity is 63%.

Conclusion: In a large academic training program, besides uLMA not been used routinely, two risk factors for LMA difficulty were identified, female gender and large neck circumference. Neck circumference is increasingly being recognized as a significant predictor across the spectrum of airway management difficulties while female gender has not been previously reported as a risk factor for difficult LMA placement.

Post analysis simulated correlation of the El-Ganzouri airway difficulty score with difficult airway

BACKGROUND

Difficult airway (DA) occurs frequently (5-15%) in clinical practice. The El-Ganzouri Risk Index (EGRI) has a high sensitivity for predicting a difficult intubation (DI). However difficult mask ventilation (DMV) was never included in the EGRI. Since DMV was not included in the EGRI assessment, and obstructive sleep apnea (OSA) is also correlated with DMV, a study correlating the prediction of DA and OSA (identified by STOP-Bang questionnaire, SB) seemed important.

METHODS

We accessed a database previously collected for a post analysis simulation of the airway difficulty predictivity of the EGRI, associated with normal and difficult airway, particularly DMV. As secondary aim, we measured the correlation between the SB prediction system and DA, compared to the EGRI.

RESULTS

A total of 2747 patients were included in the study. The proportion of patients with DI was 14.7% (95% CI 13.4-16) and the proportion of patients with DMV was 3.42% (95% CI 2.7-4.1). The incidence of DMV combined with DI was (2.3%). The optimal cutoff value of EGRI was 3. EGRI registered also an higher ability to predict DMV (AUC=0.76 (95% CI 0.71-0.81)). Adding the SB variables in the logistic model, the AUC increases with the inclusion of "observed apnea" variable (0.83 vs. 0.81, p=0.03). The area under the ROC curve for the patients with DI and DMV was 0.77 (95% CI 0.72-0.83).

CONCLUSIONS

This study confirms that the incidence of DA is not negligible and suggests the use of the EGRI as simple bedside predictive score to improve patient safety.

Difficult intubation in obese patients: incidence, risk factors, and complications in the operating theatre and in intensive care units

BACKGROUND

Intubation procedure in obese patients is a challenging issue both in the intensive care unit (ICU) and in the operating theatre (OT). The objectives of the study were (i) to compare the incidence of difficult intubation and (ii) its related complications in obese patients admitted to ICU and OT.

METHODS

We conducted a multicentre prospective observational cohort study in ICU and OT in obese (BMI≥30 kg m(-2)) patients. The primary endpoint was the incidence of difficult intubation. Secondary endpoints were the risk factors for difficult intubation, the use of difficult airway management techniques, and severe life-threatening complications related to intubation (death, cardiac arrest, severe hypoxaemia, severe cardiovascular collapse).

RESULTS

In cohorts of 1400 and 11 035 consecutive patients intubated in ICU and in the OT, 282 (20%) and 2103 (19%) were obese. In obese patients, the incidence of difficult intubation was twice more frequent in ICU than in the OT (16.3% vs 8.2%, P<0.01). In both cohorts, risk factors for difficult intubation were Mallampati score III/IV, obstructive sleep apnoea syndrome, and reduced mobility of cervical spine, while limited mouth opening, severe hypoxaemia, and coma appeared only in ICU. Specific difficult airway management techniques were used in 66 (36%) cases of difficult intubation in obese patients in the OT and in 10 (22%) cases in ICU (P=0.04). Severe life-threatening complications were significantly more frequent in ICU than in the OT (41.1% vs 1.9%, relative risk 21.6, 95% confidence interval 15.4-30.3, P<0.01).

CONCLUSIONS

In obese patients, the incidence of difficult intubation was twice more frequent in ICU than in the OT and severe life-threatening complications related to intubation occurred 20-fold more often in ICU.

CLINICAL TRIAL REGISTRATION

Current controlled trials. Identifier: NCT01532063.

Predictive factors for difficult mask ventilation in the obese surgical population

Background

Difficult Mask Ventilation (DMV), is a situation in which it is impossible for an unassisted anesthesiologist to maintain oxygen saturation >90% using 100% oxygen and positive pressure ventilation to prevent or reverse signs of inadequate ventilation during mask ventilation.  The incidence varies from 0.08 – 15%. Patient-related anatomical features are by far the most significant cause.  We analyzed data from an obese surgical population (BMI> 30 kg/m ²) to identify specific risk and predictive factors for DMV.

Methods

Five hundred and fifty seven obese patients were identified from a database of 1399 cases associated with preoperative airway examinations where mask ventilation was attempted. Assessment of mask ventilation in this group was stratified by a severity score (0-3), and a step-wise selection method was used to identify independent predictors.  The area under the curve of the receiver-operating-characteristic was then used to evaluate the model’s predictive value. Adjusted odds ratios and their 95% confidence intervals were also calculated.

Results

DMV was observed in 80/557 (14%) patients. Three independent predictive factors for DMV in obese patients were identified: age 49 years, short neck, and neck circumference  43 cm. In the current study th sensitivity for one factor is 0.90 with a specificity 0.35. However, the specificity increased to 0.80 with inclusion of more than one factor.

Conclusion

According to the current investigation, the three predictive factors are strongly associated with DMV in obese patients. Each independent risk factor alone provides a good screening for DMV and two factors substantially improve specificity. Based on our analysis, we speculate that the absence of at least 2 of the factors we identified might have a significant negative predictive value and can reasonably exclude DMV, with a negative likelihood ratio 0.81.

Difficult mask ventilation in general surgical population: observation of risk factors and predictors

Background: There are few predictors of difficult mask ventilation and a simple, objective, predictive system to identify patients at risk of difficult mask ventilation does not currently exist. We present a retrospective - subgroup analysis aimed at identifying predictive factors for difficult mask ventilation (DMV) in patients undergoing pre-operative airway assessment before elective surgery at a major teaching hospital.

Methods: Data for this retrospective analysis were derived from a database of airway assessments, management plans, and outcomes that were collected prospectively from August 2008 to May 2010 at a Level 1 academic trauma center. Patients were stratified into two groups based on the difficulty of mask ventilation and the cohorts were analyzed using univariate analysis and stepwise selection method.

Results: A total of 1399 pre-operative assessments were completed with documentation stating that mask ventilation was attempted. Of those 1399, 124 (8.9%) patients were found to be difficult to mask ventilate. A comparison of patients with and without difficult mask ventilation identified seven risk factors for DMV: age, body mass index (BMI), neck circumference, history of difficult intubation, presence of facial hair, perceived short neck and obstructive sleep apnea. Although seven risk factors were identified, no individual subject had more than four risk factors.

Conclusion: The results of this study confirm that in a real world clinical setting, the incidence of DMV is not negligible and suggest the use of a simple bedside predictive score to improve the accuracy of DMV prediction, thereby improving patient safety. Further prospective studies to validate this score would be useful.

Management of difficult airway with laryngeal mask in a child with mucopolysaccharidosis and mitral regurgitation: a case report

INTRODUCTION

Mucopolysaccharidoses (MPSs) are a group of heredity storage diseases, transmitted in an autosomal recessive manner, associated with the accumulation of glycosaminoglycans (GAGs) in various tissues and organs. The concerned patients have multiple concomitant hereditary anomalies. Considering the craniofacial abnormality in these patients, airway management may be difficult for anesthesiologists. In these patients, preanesthetic assessment is necessary and performed with the accurate assessment of airways, consisting of the physical exam and radiography, MRI or CT of head and neck. An anesthesiologist should set up a "difficult intubation set" with a flexible fiber-optic bronchoscope and also, it may be necessary to discuss with an ear-nose and throat (ENT) specialist if required, for unpredicted emergency situations.

CASE PRESENTATION

In this case-report we presented a 2-year-old boy with known MPSs with psychomotor retardation, bilateral corneal opacities, impaired hearing and vision, inguinal hernia, severe mitral regurgitation, micrognathia, coarse facial feature, stiff and short neck and restricted mouth opening. He scheduled for left inguinal hernia repair surgery.

DISCUSSION

The patient's difficult airway was managed successfully and the anesthesia of his surgical procedure had an uneventful course.

Endoscopic removal of a self-expanding metallic airway stent: A case report

Self-expanding metallic stents are sometimes placed for the management of obstructing airway lesions or conditions such as airway wall malacia or tracheal stenosis. However, endoscopic removal of these devices from the airway can pose extreme challenges for both clinical airway management as well as for the administration of general anesthesia. We report on a 61-year-old man with a complex cardiac history presenting for endoscopic stent removal necessitated by the formation of extensive granulation tissue. Comorbidities included a history of myocardial infarction, an ischemic cardiomyopathy with severe left heart failure (ejection fraction of 25%), mild right heart failure, 2+ tricuspid regurgitation status post tricuspid valve repair, and atrial fibrillation. An automatic external (wearable) cardiac defibrillator (Zoll Life Vest) was also in place. Induction of anesthesia was carried out using etomidate, with maintenance of anesthesia carried out with a propofol infusion (total intravenous anesthesia). Rocuronium was used for neuromuscular blockade. A size 4 iGel supraglottic airway and, later, rigid bronchoscopy formed the basis for airway management. Stable conditions were met through the 2-h procedure, and the patient recovered uneventfully. Our successful experience in this case leads us to propose further use of a supraglottic airway in conjunction with total intravenous anesthesia for these procedures.