The unanticipated difficult airway with recommendations for management

Temporal Trends in Difficult and Failed Tracheal Intubation in a Regional Community Anesthetic Practice

Background

When tracheal intubation is difficult or unachievable before surgery or during an emergent resuscitation, this is a critical safety event. Consensus algorithms and airway devices have been introduced in hopes of reducing such occurrences. However, evidence of improved safety in clinical practice related to their introduction is lacking. Therefore, we selected a large perioperative database spanning 2002 to 2015 to look for changes in annual rates of difficult and failed tracheal intubation.

Methods

Difficult (more than three attempts) and failed (unsuccessful, requiring awakening or surgical tracheostomy) intubation rates in patients 18 yr and older were compared between the early and late periods (pre- vs. post-January 2009) and by annual rate join-point analysis. Primary findings from a large, urban hospital were compared with combined observations from 15 smaller facilities.

Results

Analysis of 421,581 procedures identified fourfold reductions in both event rates between the early and late periods (difficult: 6.6 of 1,000 vs. 1.6 of 1,000, P < 0.0001; failed: 0.2 of 1,000 vs. 0.06 of 1,000, P < 0.0001), with join-point analysis identifying two significant change points (2006, P = 0.02; 2010, P = 0.03) including a pre-2006 stable period, a steep drop between 2006 and 2010, and gradual decline after 2010. Data from 15 affiliated practices (442,428 procedures) demonstrated similar reductions.

Conclusions

In this retrospective assessment spanning 14 yr (2002 to 2015), difficult and failed intubation rates by skilled providers declined significantly at both an urban hospital and a network of smaller affiliated practices. Further investigations are required to validate these findings in other data sets and more clearly identify factors associated with their occurrence as clues to future airway management advancements.

Survey about the Extubation Practice among Anaesthesiologists in Kosovo

BACKGROUND

Tracheal extubations may be performed before or after awakening from anaesthesia. The advantage of extubation during anaesthesia may avoid all the unpleasant effects of fully awake extubation such as severe hypertension and tachycardia, malignant dysrhythmias, myocardial ischemia laryngospasm, and cough induced high intraocular and intracranial pressure.

AIM

To show the current practice of performing extubations in Kosovo, as well as the advantage and disadvantage in performing this procedure in an awake patient or inpatient in light anaesthesia.

MATERIAL

This study is conducted at the Regional Hospitals and the University Clinical Center of Kosovo during the year 2015. A questionnaire is given to the anesthesiologists to collect information about the techniques used for extubation, timing and management of extubation.

RESULTS

Based on this survey results that 86% of an anesthesiologist (71) extubate the patients when they are completely awake, while 14% of them (12) prefer to extubate the patients under light anaesthesia. From all anesthesiologists involved in this study, forty of them reported problems during extubation. Complications were related to airway, and they are treated by oxygenation and jaw support, but in rare cases, reintubation were performed.

CONCLUSION

Complications during extubation remain important risk factor while extubation during light anaesthesia can minimise some of them.

Human and equipment resources for difficult airway management, airway education programs, and capnometry use in Japanese emergency departments: a nationwide cross-sectional study

BACKGROUND

Although human and equipment resources, proper training, and the verification of endotracheal intubation are vital elements of difficult airway management (DAM), their availability in Japanese emergency departments (EDs) has not been determined. How ED type and patient volume affect DAM preparation is also unclear. We conducted the present survey to address this knowledge gaps.

METHODS

This nationwide cross-sectional study was conducted from April to September 2016. All EDs received a mailed questionnaire regarding their DAM resources, airway training methods, and capnometry use for tube placement. Outcome measures were the availability of: (1) 24-h in-house back-up; (2) key DAM resources, including a supraglottic airway device (SGA), a dedicated DAM cart, surgical airway devices, and neuromuscular blocking agents; (3) anesthesiology rotation as part of an airway training program; and (4) the routine use of capnometry to verify tube placement. EDs were classified as academic, tertiary, high-volume (upper quartile of annual ambulance visits), and urban.

RESULTS

Of the 530 EDs, 324 (61.1%) returned completed questionnaires. The availability of in-house back-up coverage, surgical airway devices, and neuromuscular blocking agents was 69.4, 95.7, and 68.5%, respectively. SGAs and dedicated DAM carts were present in 51.5 and 49.7% of the EDs. The rates of routine capnometry use (47.8%) and the availability of an anesthesiology rotation (38.6%) were low. The availability of 24-h back-up coverage was significantly higher in academic EDs and tertiary EDs in both the crude and adjusted analysis. Similarly, neuromuscular blocking agents were more likely to be present in academic EDs, high-volume EDs, and tertiary EDs; and the rate of routine use of capnometry was significantly higher in tertiary EDs in both the crude and adjusted analysis.

CONCLUSIONS

In Japanese EDs, the rates of both the availability of SGAs and DAM carts and the use of routine capnometry to confirm tube placement were approximately 50%. These data demonstrate the lack of standard operating procedures for rescue ventilation and post-intubation care. Academic, tertiary, and high-volume EDs were likely to be well prepared for DAM.

Analysis of Production, Impact, and Scientific Collaboration on Difficult Airway Through the Web of Science and Scopus (1981-2013)

BACKGROUND

Bibliometrics, the statistical analysis of written publications, is an increasingly popular approach to the assessment of scientific activity. Bibliometrics allows researchers to assess the impact of a field, or research area, and has been used to make decisions regarding research funding. Through bibliometric analysis, we hypothesized that a bibliometric analysis of difficult airway research would demonstrate a growth in authors and articles over time.

METHODS

Using the Web of Science (WoS) and Scopus databases, we conducted a search of published manuscripts on the difficult airway from January 1981 to December 2013. After removal of duplicates, we identified 2412 articles. We then analyzed the articles as a group to assess indicators of productivity, collaboration, and impact over this time period.

RESULTS

We found an increase in productivity over the study period, with 37 manuscripts published between 1981 and 1990, and 1268 between 2001 and 2010 (P < .001). The difficult airway papers growth rate was bigger than that of anesthesiology research in general, with CAGR (cumulative average growth rate) since 1999 for difficult airway >9% for both WoS and Scopus, and CAGR for anesthesiology as a whole =0.64% in WoS, and =3.30% in Scopus. Furthermore, we found a positive correlation between the number of papers published per author and the number of coauthored manuscripts (P < .001). We also found an increase in the number of coauthored manuscripts, in international cooperation between institutions, and in the number of citations for each manuscript. For any author, we also identified a positive relationship between the number of citations per manuscript and the number of papers published (P < .001).

CONCLUSIONS

We found a greater increase over time in the number of difficult airway manuscripts than for anesthesiology research overall. We found that collaboration between authors increases their impact, and that an increase in collaboration increases citation rates. Publishing in English and in certain journals, and collaborating with certain authors and institutions, increases the visibility of manuscripts published on this subject.

The Impact of Residual Neuromuscular Blockade, Oversedation, and Hypothermia on Adverse Respiratory Events in a Postanesthetic Care Unit: A Prospective Study of Prevalence, Predictors, and Outcomes

BACKGROUND

Residual neuromuscular blockade (RNMB) has been linked to adverse respiratory events (AREs) in the postanesthetic care unit (PACU). However, these events are often not attributed to RNMB by anesthesiologists because they may also be precipitated by other factors including obstructive sleep apnea, opioids, or hypnotic agents. Many anesthesiologists believe RNMB occurs infrequently and is rarely associated with adverse outcomes. This study evaluated the prevalence and predictors of RNMB and AREs.

METHODS

This prospective cohort study included 599 adult patients undergoing general anesthesia who received neuromuscular blocking agents. Baseline demographic, surgical, and anesthetic variables were collected. RNMB was defined as a train-of-four ratio below 0.90 measured by electromyography on admission to the PACU. AREs were defined based on the modified Murphy's criteria.

RESULTS

RNMB was present in 186 patients (31% [95% confidence interval (CI), 27%-35%]) on admission to the PACU. One or more AREs were experienced by 97 patients (16% [95% CI 13-19]). AREs were more frequent in patients with RNMB (21% vs 14%, P = .033). RNMB was significantly associated with age (adjusted relative risk [RR], 1.17 [95% CI, 1.06-1.29] per 10-year increase), type of operation (adjusted RR, 0.59 [95% CI, 0.34-0.99] for laparoscopic surgery compared with open abdominal surgery), and duration of operation (adjusted RR, 0.59 [95% CI, 0.39-0.86] for ≥90 minutes compared with <90 minutes). Using multivariate logistic regression, AREs were found to be independently associated with decreased level of consciousness (adjusted RR, 4.76 [95% CI, 1.49-6.76] for unrousable/unconscious compared with alert/awake) and lower core temperature (adjusted RR, 1.43 [95% CI, 1.04-1.92] per 1°C decrease). Although univariate analysis found a significant association between AREs and RNMB, the significance became borderline after adjusting for other covariates (adjusted RR, 1.46 [95% CI, 0.99-2.08]).

CONCLUSIONS

The prevalence of RNMB in the PACU was >30%. Older age, open abdominal surgery, and duration of operation <90 minutes were associated with increased risk of RNMB in our patients. Our RR estimate for AREs was highest for depressed level of consciousness. When AREs occur in the PACU, potentially preventable causes including RNMB, hypothermia, and reduced level of consciousness should be readily identified and treated appropriately. Delaying extubation until the patient is awake and responsive may reduce AREs.

Videolaryngoscopy in Neonates, Infants, and Children

Airway management is vital during anesthetic care and during resuscitative efforts in the PICU, the emergency department, and the delivery room. Given specific anatomic and physiologic differences, neonates and infants may be more prone to complications during airway management. Videolaryngoscopy may offer an alternative to or advantages over direct laryngoscopy in specific clinical scenarios. The following article reviews some of the basic types of videolaryngoscopy and discusses their potential applications in the pediatric population.

The effects of dynamic airway photographs on preoperative airway planning among a panel of anesthetists

STUDY OBJECTIVE

To determine whether having preoperative airway photographs will change the preanesthetic airway plan.

DESIGN

Questionnaire.

SETTING

American academic medical center (Brigham and Women's Hospital, Boston MA).

SUBJECTS

Twenty-five test subjects (American Society of Anesthesiologists 1-4) were enrolled to have their preoperative airway photographs taken as well as to have a customary preoperative history and physical examination. In addition, 15 anesthetists were enrolled to review the subjects' preoperative history, physical examination, and preoperative airway photographs.

MEASUREMENTS

All 15 anesthetists were asked to fill out a survey for airway management for each test subject.

MAIN RESULTS

All 15 anesthetists completed the survey. Across all providers, plans were changed a median of 24% (95% confidence interval [CI], 12.7-38.6). Among attending anesthesiologists, airway management plans were changed 30% of the time (95% CI, 12.4-40.0), whereas among nonattending level providers, plans changed 24% of the time (95% CI, 12.0-38.8). χ² Tests found no difference between the percent change of airway plans between attending and nonattending level providers (P=.306).

CONCLUSIONS

Our findings suggest that the addition of dynamic airway photographs to preoperative airway reports affects airway management plans among a variety of anesthesia care providers. In general, dynamic airway photographs can aid preoperative airway management planning.

Determination of the diagnostic value of the Modified Mallampati Score, Upper Lip Bite Test and Facial Angle in predicting difficult intubation: A prospective descriptive study

BACKGROUND

Difficult intubation is a significant cause of mortality and morbidity related to anesthesia. We decided to evaluate the value of Modified Mallampati Score, Upper Lip Bite Test and Facial Angle in the prediction of difficult intubation.

METHODS

In a prospective descriptive study, data from 132 patients who were candidates for elective maxillofacial surgeries under general anesthesia were gathered. Facial Angles were measured by a maxillofacial surgeon according to cephalometry. The Modified Mallampati Score and Upper Lip Bite Test were first measured by an anesthesiologist and then another anesthesiologist was assigned to record the Cormack and Lehane score during the intubation. Grades 3 and 4 were considered as difficult intubation. Sensitivity, specificity, positive predictive value, negative predictive value and Youden index were calculated for all tests.

RESULTS

Difficult intubation was reported in 12% of the patients. Facial Angle≤82.5° can predict difficult intubation with 87.5% sensitivity and 88.8% specificity. Among the three tests, a high Modified Mallampati Score had the highest specificity (94.5%) and a high Modified Mallampati Score and Facial Angle (FA≤82.5°) had the highest sensitivity (87.5%). The highest NPV, sensitivity and Youden index were observed when using Facial Angle with the Modified Mallampati Score or with Upper Lip Bite Test.

CONCLUSIONS

Facial Angle has a high sensitivity, NPV and Youden index for the prediction of difficult intubation, but the best result is achieved when Facial Angle is used in combination with either the Modified Mallampati Score or Upper Lip Bit Test.

Comparison of success of tracheal intubation using Macintosh laryngoscope-assisted Bonfils fiberscope and Truview video laryngoscope in simulated difficult airway

Background and Aims:

Restriction of head and neck movements prevents the alignment of the oral, pharyngeal, and laryngeal axes and increases the incidence of difficult tracheal intubation in patients with cervical spine fractures. Video laryngoscopes have gained an important role in the management of difficult intubation, especially in situations with limited head and neck movements. This study compares the success of intubation using Macintosh laryngoscope assisted Bonfils^® fiberscope (ML-BF) with Truview^PCD video laryngoscope (TV) in patients with simulated restricted head and neck movements.

Material and Methods:

One hundred and fifty-two patients satisfying the inclusion criteria were randomly allocated to two groups of 76 each. Patients were made to lie supine on the table without a pillow and a soft collar was used to restrict head and neck movements. After a standardized premedication-induction sequence, tracheal intubation was done either with ML-BF or TV. Success of intubation, time taken for successful intubation, hemodynamic changes, airway trauma, and postoperative oropharyngeal morbidity were noted.

Results:

Intubation was successful in all the 76 patients in direct laryngoscopy-Bonfils fiberscope group and 75 out of 76 patients in TV group within the specified time (90 s). The median time taken for successful intubation with TV and ML-BF were 44 (range 26–80) s and 49 (range 28–83) s, respectively. Hemodynamic changes, airway trauma, and postoperative oropharyngeal morbidity were similar in both groups.

Conclusion:

Both TV and ML-BF are equally effective for successful tracheal intubation in patients with simulated restricted head and neck movements. In cases of difficult laryngeal visualization with routine Macintosh laryngoscope, Bonfils can be used as an adjunct to achieve successful intubation in the same laryngoscopy attempt.

Is Ultrasound a Valid and Reliable Imaging Modality for Airway Evaluation?: An Observational Computed Tomographic Validation Study Using Submandibular Scanning of the Mouth and Oropharynx

OBJECTIVES

Ultrasound (US) imaging of the airway may be useful in predicting difficulty of airway management (DAM); but its use is limited by lack of proof of its validity and reliability. We sought to validate US imaging of the airway by comparison to CT-scan, and to assess its inter- and intra-observer reliability. We used submandibular sonographic imaging of the mouth and oropharynx to examine how well the ratio of tongue thickness to oral cavity height correlates with the ratio of tongue volume to oral cavity volume, an established tomographic measure of DAM.

METHODS

A cohort of 34 patients undergoing CT-scan was recruited. Study standardized assessments included CT-measured ratios of tongue volume to oropharyngeal cavity volume; tongue thickness to oral cavity height; and US-measured ratio of tongue thickness to oral cavity height. Two sonographers independently performed US imaging of the airway before and after CT-scan.

RESULTS

Our findings indicate that the US-measured ratio of tongue thickness to oral cavity height highly correlates with the CT-measured ratio of tongue volume to oral cavity volume. US measurements also demonstrated strong inter- and intra-observer reliability.

CONCLUSIONS

This study suggests that US is a valid and reliable tool for imaging the oral and oropharyngeal parts of the airway, as well as for measuring the volumetric relationship between the tongue and oral cavity, and may therefore be a useful predictor of DAM.

Video Laryngoscopy Improves Odds of First-Attempt Success at Intubation in the Intensive Care Unit. A Propensity-matched Analysis

RATIONALE

Urgent tracheal intubation is performed frequently in intensive care units and incurs higher risk than when intubation is performed under more controlled circumstances. Video laryngoscopy may improve the chances of successful tracheal intubation on the first attempt; however, existing comparative data on outcomes are limited.

OBJECTIVES

To compare first-attempt success and complication rates during intubation when using video laryngoscopy compared with traditional direct laryngoscopy in a tertiary academic medical intensive care unit.

METHODS

We prospectively collected and analyzed data from a continuous quality improvement database of all intubations in one medical intensive care unit between January 1, 2012, and December 31, 2014. Propensity matching and multivariable logistic regression were used to reduce the risk of bias and control for confounding.

MEASUREMENTS AND MAIN RESULTS

A total of 809 intubations took place over the study period. Of these, 673 (83.2%) were performed using video laryngoscopy and 136 (16.8%) using direct laryngoscopy. First-attempt success with video laryngoscopy was 80.4% (95% confidence interval [CI], 77.2-83.3%) compared with 65.4% (95% CI, 56.8-73.4%) for intubations performed with direct laryngoscopy (P < 0.001). In a propensity-matched analysis, the odds ratio for first-attempt success with video laryngoscopy versus direct laryngoscopy was 2.81 (95% CI, 2.27-3.59). The rate of arterial oxygen desaturation events during the first intubation attempt was significantly lower for video laryngoscopy than for direct laryngoscopy (18.3% vs. 25.9%; P = 0.04). The rate of esophageal intubation during any attempt was also significantly lower for video laryngoscopy (2.1% vs. 6.6%; P = 0.008).

CONCLUSIONS

Video laryngoscopy was associated with significantly improved odds of first-attempt success at tracheal intubation by nonanesthesiologists in a medical intensive care unit. Esophageal intubation and oxygen desaturation occurred less frequently with the use of video laryngoscopy. Randomized clinical trials are needed to confirm these findings.

Videolaryngoscopy versus direct laryngoscopy for adult patients requiring tracheal intubation

BACKGROUND

Successful tracheal intubation during general anaesthesia traditionally requires a line of sight to the larynx attained by positioning the head and neck and using a laryngoscope to retract the tongue and soft tissues of the floor of the mouth. Difficulties with intubation commonly arise, and alternative laryngoscopes that use digital and/or fibreoptic technology have been designed to improve visibility when airway difficulty is predicted or encountered. Among these devices, a rigid videolaryngoscope (VLS) uses a blade to retract the soft tissues and transmits a lighted video image to a screen.

OBJECTIVES

Our primary objective was to assess whether use of videolaryngoscopy for tracheal intubation in adults requiring general anaesthesia reduces risks of complications and failure compared with direct laryngoscopy. Our secondary aim was to assess the benefits and risks of these devices in selected population groups, such as adults with obesity and those with a known or predicted difficult airway.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and Embase on 10 February 2015. Our search terms were relevant to the review question and were not limited by outcomes. We carried out clinical trials register searches and forward and backward citation tracking. We reran the search on 12 January 2016; we added potential new studies of interest from the 2016 search to a list of 'Studies awaiting classification', and we will incorporate these studies into the formal review during the review update.

SELECTION CRITERIA

We considered all randomized controlled trials and quasi-randomized studies with adult patients undergoing laryngoscopy performed with a VLS or a Macintosh laryngoscope in a clinical, emergency or out-of-hospital setting. We included parallel and cross-over study designs.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data, consulting a third review author to resolve disagreements. We used standard Cochrane methodological procedures, including assessment of risk of bias.

MAIN RESULTS

We included 64 studies identified during the 2015 search that enrolled 7044 adult participants and compared a VLS of one or more designs with a Macintosh laryngoscope. We identified 38 studies awaiting classification and seven ongoing studies. Of the 64 included studies, 61 included elective surgical patients, and three were conducted in an emergency setting. Among 48 studies that included participants without a predicted difficult airway, 15 used techniques to simulate a difficult airway. Seven recruited participants with a known or predicted difficult airway, and the remaining studies did not specify or included both predicted and not predicted difficult airways. Only two studies specifically recruited obese participants. It was not possible to blind the intubator to the device, and we noted a high level of inevitable heterogeneity, given the large number of studies.Statistically significantly fewer failed intubations were reported when a VLS was used (Mantel-Haenszel (M-H) odds ratio (OR), random-effects 0.35, 95% confidence Interval (CI) 0.19 to 0.65; 38 studies; 4127 participants), and fewer failed intubations occurred when a VLS was used in participants with an anticipated difficult airway (M-H OR, random-effects 0.28, 95% CI 0.15 to 0.55; six studies; 830 participants). We graded the quality of this evidence as moderate on the basis of the GRADE system. Failed intubations were fewer when a VLS was used in participants with a simulated difficult airway (M-H OR, random-effects 0.18, 95% CI 0.04 to 0.77; nine studies; 810 participants), but groups with no predicted difficult airway provided no significant results (M-H OR, random-effects 0.61, 95% CI 0.22 to 1.67; 19 studies; 1743 participants).Eight studies reported on hypoxia, and only three of these described any events; results showed no differences between devices for this outcome (M-H OR, random-effects 0.39, 95% CI 0.10 to 1.44; 1319 participants). Similarly, few studies reported on mortality, noting no differences between devices (M-H OR, fixed-effect 1.09, 95% CI 0.65 to 1.82; two studies; 663 participants), and only one study reporting on the occurrence of respiratory complications (78 participants); we graded these three outcomes as very low quality owing to lack of data. We found no statistically significant differences between devices in the proportion of successful first attempts (M-H OR, random-effects 1.27, 95% CI 0.77 to 2.09; 36 studies; 4731 participants) nor in those needing more than one attempt. We graded the quality of this evidence as moderate. Studies reported no statistically significant differences in the incidence of sore throat in the postanaesthesia care unit (PACU) (M-H OR, random-effects 1.00 (95% CI 0.73 to 1.38); 10 studies; 1548 participants) nor at 24 hours postoperatively (M-H OR random-effects 0.54, 95% CI 0.27 to 1.07; eight studies; 844 participants); we graded the quality of this evidence as moderate. Data combined to include studies of cross-over design revealed statistically significantly fewer laryngeal or airway traumas (M-H OR, random-effects 0.68, 95% CI 0.48 to 0.96; 29 studies; 3110 participants) and fewer incidences of postoperative hoarseness (M-H OR, fixed-effect 0.57, 95% CI 0.36 to 0.88; six studies; 527 participants) when a VLS was used. A greater number of laryngoscopies performed with a VLS achieved a view of most of the glottis (M-H OR, random-effects 6.77, 95% CI 4.17 to 10.98; 22 studies; 2240 participants), fewer laryngoscopies performed with a VLS achieved no view of the glottis (M-H OR, random-effects 0.18, 95% CI 0.13 to 0.27; 22 studies; 2240 participants) and the VLS was easier to use (M-H OR, random-effects 7.13, 95% CI 3.12 to 16.31; seven studies; 568 participants).Although a large number of studies reported time required for tracheal intubation (55 studies; 6249 participants), we did not present an effects estimate for this outcome owing to the extremely high level of statistical heterogeneity (I2 = 96%).

AUTHORS' CONCLUSIONS

Videolaryngoscopes may reduce the number of failed intubations, particularly among patients presenting with a difficult airway. They improve the glottic view and may reduce laryngeal/airway trauma. Currently, no evidence indicates that use of a VLS reduces the number of intubation attempts or the incidence of hypoxia or respiratory complications, and no evidence indicates that use of a VLS affects time required for intubation.

Novel Airway Training Tool that Simulates Vomiting: Suction-Assisted Laryngoscopy Assisted Decontamination (SALAD) System

INTRODUCTION

We present a novel airway simulation tool that recreates the dynamic challenges associated with emergency airways. The Suction-Assisted Laryngoscopy Assisted Decontamination (SALAD) simulation system trains providers to use suction to manage emesis and bleeding complicating intubation.

METHODS

We modified a standard difficult-airway mannequin head (Nasco, Ft. Atkinson, WI) with hardware-store equipment to enable simulation of vomiting or hemorrhage during intubation. A pre- and post-survey was used to assess the effectiveness of the SALAD simulator. We used a 1-5 Likert scale to assess confidence in managing the airway of a vomiting patient and comfort with suction techniques before and after the training exercise.

RESULTS

Forty learners participated in the simulation, including emergency physicians, anesthesiologists, paramedics, respiratory therapists, and registered nurses. The average Likert score of confidence in managing the airway of a vomiting or hemorrhaging patient pre-session was 3.10±0.49, and post-session 4.13±0.22. The average score of self-perceived skill with suction techniques in the airway scenario pre-session was 3.30±0.43, and post-session 4.03±0.26. The average score for usefulness of the session was 4.68±0.15, and the score for realism of the simulator was 4.65±0.17.

CONCLUSION

A training session with the SALAD simulator improved trainee's confidence in managing the airway of a vomiting or hemorrhaging patient. The SALAD simulation system recreates the dynamic challenges associated with emergency airways and holds promise as an airway training tool.

Use-Dependent Curvature Changes in the GlideRite® Reusable Intubation Stylet

The Glidescope® is one of the most widely used video laryngoscopes in the market. It is often used with a purpose-built, reusable, "nonmalleable" stainless steel stylet, the GlideRite®. In this study, we investigated whether this stylet retains its original curvature with repeated use and sterilization. To evaluate the shape and curvature of the stylets, high-resolution digital photographs were made of 55 GlideRite stylets (5 new and 50 randomly selected from operating room stock) laid on a grid background and analyzed using Adobe Photoshop®. In a similar fashion, 1 new stylet was inserted into and removed 100 times from an endotracheal tube and photographed every 20 cycles to determine the impact of use on stylet shape. For the 5 new stylets, the handle-to-tip angle was very consistent (23.44° ± 1.04°). The stylets in clinical use varied widely in their configuration. For analysis, they were divided into 3 groups based on the handle-to-tip angle: ±1 SD of the new stylets, those with a shallower angle (straighter), and those with a steeper angle (more curved). The handle-to-tip angles were as follows: 23.07° ± 0.80° (±1 SD), 18.39° ± 2.59° (straighter), and 27.65° ± 2.73° (more curved). Analysis of variance showed that the new and ±1 SD groups were not significantly different, but both the straighter (P = 0.0002) and more curved (P = 0.0048) groups were significantly different from new. The repeated insertion and removal of a new stylet resulted in gradual straightening of the curve of the stylet from 22° at baseline to 19.2° after 100 insertion/removal cycles. Used GlideRite reusable stylets are not reliably equivalent to new ones in terms of their shape or curvature. Given that the repeated insertion and removal of a new stylet from an endotracheal tube resulted in their straightening, it is likely that clinical use has the same effect. Because many used stylets were actually more curved than the new ones, we hypothesize that practitioners likely bend the nonmalleable stylets to improve clinical utility, but often fail to recapture the manufacturer-intended curve. The clinical relevance of the change in shape of the GlideRite stylet remains to be determined; it is that possible intubation may be more difficult than expected compared with the use of new stylets.

Regional anesthesia in difficult airway: The quest for a solution continues

Difficult airway, a scenario with potentially life threatening outcome, is routinely encountered by an anesthesiologist leaving him with the dilemma of whether to use regional anesthesia (RA) or general anesthesia. Our study aims to look into this problem. The literature search was performed in the Google, PubMed, and Medscape using key words "regional anesthesia, difficult airway, pregnancy, ventilation, intubation, epidural anesthesia, nerve blocks." More than 38 free full articles and books published from the year 1987 to 2014 were retrieved and studied. At first sight, RA may appear to offer an ideal solution as it helps to avoid the problem of difficult airway. However, the possibility of a total spinal block, failed or incomplete RA, local anesthetic toxicity or unforeseen surgical complication may make it imperative that the airway is secured. The correct decision can only be made by the anesthetist when all the relevant clinical information is taken into account. It is also important to ensure that before considering RA in a patient of difficult airway, an anesthesiologist must have a preformulated strategy for intubation.

Bedside tests to predict laryngoscopic difficulty in pediatric patients

BACKGROUND AND OBJECTIVES

Pediatric airway management is a priority during anesthesia, critical care and emergency medicine. The purpose of this study is to validate bedside tests that predict airway management difficulty in anesthetized children.

METHODS

Children under 12 years of age were recruited in a cross-sectional study to assess the value of some anthropometric measures as predictors of laryngoscopic difficulty. The patients were divided into three groups by age. Weight, height, neck circumference, BMI (body mass index), inter incisors distance thyromental distance, sternomental distance, frontal plane to chin distance (FPCD) and the Mallampati index were determined and were correlated with the CML (Cormack & Lehane classification).

RESULTS

The incidence of difficult laryngoscopy (CML 3 or 4) was 3.58%. Factors that were significantly associated with laryngoscopic difficulty included short inter incisors distance, high FPCD, thyromental distance, sternomental distance and the Mallampati index. The FPCD/weight index exhibited a higher area under the ROC curve than any other variable considered.

CONCLUSIONS

This study confirms that the FPCD and the FPCD/weight ratio are the most consistent predictors of laryngoscopic difficulty in pediatric patients. For patients over 6 months of age, the IID also correlated with laryngoscopic difficulty. For children who were capable of obeying simple orders, the Mallampati test correlated better with laryngoscopic difficulty than did the Mallampati test with phonation. Our results strongly suggest that skilled professionals should perform airway management in children, especially in patients with a high FPCD or a high FPCD/weight ratio.

The Difficult Paediatric Airway: Two Cases of large Cystic Hygroma

This is a report of a two cases of difficult intubation experienced in paediatric surgical cases. Both the infants, aged one and three-month-old respectively, had very large cystic hygroma of the neck area. Prior hematological and radiological investigations (USG and CT scan of the swelling) and preanaesthesia check up was done and cases were posted for surgical excision. Case I had difficult airway due to pressure of the tumour/cystic hygroma over the airway and posed difficulty for intubation, but was managed well. Case II had respiratory distress during preoperative period. She had been postponed for surgical excision of the cystic hygroma of neck twice due to the difficulties experienced during intubation. Needle aspiration of hygroma fluid helped to reduce the respiratory distress, and the size of the tumour as well, which further helped in the smooth intubation after a week. The postoperative period was uneventful in both the infants.

McGRATH MAC videolaryngoscope versus Macintosh laryngoscope for orotracheal intubation in intensive care patients: the randomised multicentre MACMAN trial study protocol

INTRODUCTION

Critically ill patients with acute respiratory, neurological or cardiovascular failure requiring invasive mechanical ventilation are at high risk of difficult intubation and have organ dysfunctions associated with complications of intubation and anaesthesia such as hypotension and hypoxaemia. The complication rate increases with the number of intubation attempts. Videolaryngoscopy improves elective endotracheal intubation. McGRATH MAC is the lightest videolaryngoscope and the most similar to the Macintosh laryngoscope. The primary goal of this trial was to determine whether videolaryngoscopy increased the frequency of successful first-pass intubation in critically ill patients, compared to direct view Macintosh laryngoscopy.

METHODS AND ANALYSIS

MACMAN is a multicentre, open-label, randomised controlled superiority trial. Consecutive patients requiring intubation are randomly allocated to either the McGRATH MAC videolaryngoscope or the Macintosh laryngoscope, with stratification by centre and operator experience. The expected frequency of successful first-pass intubation is 65% in the Macintosh group and 80% in the videolaryngoscope group. With α set at 5%, to achieve 90% power for detecting this difference, 185 patients are needed in each group (370 in all). The primary outcome is the proportion of patients with successful first-pass orotracheal intubation, compared between the two groups using a generalised mixed model to take the stratification factors into account.

ETHICS AND DISSEMINATION

The study project has been approved by the appropriate ethics committee (CPP Ouest 2, # 2014-A00674-43). Informed consent is not required, as both laryngoscopy methods are considered standard care in France; information is provided before study inclusion. If videolaryngoscopy proves superior to Macintosh laryngoscopy, its use will become standard practice, thereby decreasing first-pass intubation failure rates and, potentially, the frequency of intubation-related complications. Thus, patient safety should benefit. Further studies would be warranted to determine whether videolaryngoscopy is also beneficial in the emergency room and for prehospital emergency care.

TRIAL REGISTRATION NUMBER

NCT02413723; Pre-results.

Comparison of the C-MAC Videolaryngoscope and Rigid Fiberscope with Direct Laryngoscopy in Easy and Difficult Airway Scenarios: A Manikin Study

BACKGROUND

Intubation is a fundamental skill in maintaining adequate oxygenation and ventilation of seriously ill patients.

OBJECTIVES

To compare the C-MAC video laryngoscope and Bonfils intubation fiberscope with direct laryngoscopy in simulated easy and difficult airway scenarios.

METHODS

This was a prospective, randomized-controlled cross-sectional study. Thirty emergency medicine residents attempted to intubate a manikin using four progressively more difficult airway settings (normal airway [scenario 1], cervical spine immobilization [scenario 2], cervical spine immobilization + tongue swelling scenario [scenario 3], and cervical spine immobilization + tongue swelling + limited jaw opening scenario [scenario 4]) with both the C-MAC video laryngoscope and the Bonfils intubation fiberscope and direct laryngoscope.

RESULTS

In the first and the second scenarios, there were no statistically significant differences between the airway devices in terms of the duration of endotracheal intubation, the viewing duration of the glottic opening, and endotracheal tube insertion time. There was no statistically significant difference between the laryngoscopes in terms of the duration of endotracheal intubation and endotracheal tube insertion time in the third scenario. The overall success rates and the viewing duration of the glottic opening were shorter with the C-MAC and Bonfils in scenarios 3 and 4. Furthermore, the duration of intubation was better with Bonfils in scenario 4. The severity of dental trauma was lowest with the Bonfils in all scenarios. The device difficulty score was greatest with the Macintosh blade, except in the normal airway scenario. The most preferred airway device was the C-MAC.

CONCLUSION

The Bonfils and C-MAC enabled better visualization of the glottic opening when compared with the Macintosh laryngoscope.

Head and neck surgery in a tertiary centre: Predictors of difficult airway and anaesthetic management

Introduction:

The management of head and neck surgical patients is associated with increased morbidity and mortality, and so anticipating the difficult airway is important.

Methods:

We undertook a prospective survey on consecutive adult patients scheduled on the elective operating lists of four head and neck consultant surgeons. Data were collected over a 36 month period. Data included: patient characteristics; routine predictors of difficulty in airway management (bedside tests of the airway, a history of previous surgery or radiotherapy and the presence of airway symptoms); laryngoscopy grade; method of anaesthesia and airway management; and any airway complications arising during induction of anaesthesia and extubation.

Results:

The ‘study’ group consisted of 818 patients. The ‘direct laryngoscopy’ group contained 674 patients, that is, patients who had direct laryngoscopy and could therefore be classified as easy or difficult intubation. The prevalence of difficult intubation was 12.6%. Factors or tests that were statistically significantly associated with difficult intubation were: history of difficult airway; previous head or neck radiotherapy treatment; presence of airway symptoms; presence of moderate or severe limited neck movement; and short interdental distance. The sensitivity, specificity and positive predictive values were: history of difficult airway 16.5%, 98.6% and 63.6%; previous radiotherapy 12.9%, 96.6% and 35.5%; airway symptoms 42.9%, 69.6% and 15.9%; moderate/severe neck limitation 16.7%, 97.2% and 46.7%; Mallampati score 3 or 4, 38.8%, 83.8% and 25.8%; and interdental distance 9.4%, 98.8% and 53.3%, respectively. The Bonfils intubation fibrescope was the most commonly used indirect laryngoscopy device (63.9% of all such cases). Twenty-six patients (3.2%) had complications during their initial airway management after induction of anaesthesia. There was one case of ‘cannot intubate, cannot oxygenate’, which required an emergency tracheostomy.

Conclusion:

The prevalence of difficult intubation in head and neck surgical patients was higher than in the general population, but predictive tests for difficult intubation have poor to moderate value. In our study, rates of difficult face mask ventilation, failed intubation and complications during induction and extubation were low. However, serious morbidity, although rare, can still be encountered. Head and neck surgical patients can be managed safely in a tertiary centre where there is appropriate surgical and anaesthetic expertise in managing difficult airways.

Prospective validation of the modified LEMON criteria to predict difficult intubation in the ED

BACKGROUND

Evidence to predict difficult intubation remains scarce in the emergency department (ED) setting. A previously defined clinical decision rule, the modified LEMON criteria, may provide a reliable and reproducible means of identifying difficult intubations. We aimed to prospectively evaluate the external validity of the modified LEMON criteria in the EDs.

METHODS

We conducted a 13-center prospective observational study, the second Japanese Emergency Airway Network study. We prospectively collected data on all patients undergoing intubations in the ED from February 2012 through September 2014. The primary outcomes were sensitivity, specificity, and predictive values of the modified LEMON criteria for predicting difficult intubation (≥2 attempts by emergency attending physicians or anesthesiologists).

RESULTS

The database recorded a total of 4034 encounters (capture rate, 96%) in the EDs. Of these, 3313 patients (84%) underwent the intubation attempt with a direct laryngoscope and 610 patients (16%) with a video laryngoscope. The proportion of difficult intubation was 5.4% (95% confidence interval [CI], 4.7%-6.2%) in the direct laryngoscope group and 7.4% (95% CI, 5.6%-9.7%) in the video laryngoscope group. The sensitivity was 85.7% (95% CI, 79.3%-90.4%) with direct laryngoscope and 94.9% (95% CI, 83.5%-98.6%) with video laryngoscope. The specificity was 47.6% (95% CI, 47.2%-47.9%) and 40.3% (95% CI, 39.4%-40.6%), respectively. The negative predictive value was 98.2% (95% CI, 97.5%-98.8%) and 99.0% (95% CI, 96.6%-99.7%), respectively.

CONCLUSIONS

In this multicenter prospective study, we found a high sensitivity and a negative predictive value of the modified LEMON criteria for predicting difficult intubation. The modified LEMON might assist ED providers in better identifying difficult intubations.

Quest for an Ideal Route of Intubation for Oral and Maxillofacial Surgical Manoeuvres

PURPOSE

The optimal route of intubation that may be planned for different oral and maxillofacial surgical manoeuvres.

MATERIALS AND METHODS

A study was performed on patients who underwent nasal, oral or submental route of intubation for elective oral and maxillofacial surgery under general anaesthesia. The study variables were the anaesthetic and surgeon factors that should be taken into consideration before intubation and during surgery, and also algorithms for uneventful surgical procedures. The outcome variables were influence of the 'route of intubation' on 'surgical technique' and vice versa. Overall results were compiled, tabulated and analysed using SPSS version 14.0.

RESULTS

The study sample comprised of 634 patients. It was found that 35 % (204) nasal, 7.5 % (4) oral and 0 % submental route of intubation had statistically significant influence on oral and maxillofacial surgical procedures and vice versa (p < 0.001).

CONCLUSION

This present study concluded that the surgical access and visibility was immensely improved by following the anaesthetic and surgeon factors in conjunction with algorithms described for uneventful oral and maxillofacial surgical procedures. Further, this has also substantially minimized the influence of the 'route of intubation' on 'surgical technique' and vice versa.

Comparison of five methods in predicting difficult laryngoscopy: Neck circumference, neck circumference to thyromental distance ratio, the ratio of height to thyromental distance, upper lip bite test and Mallampati test

Background:

Preoperative airway assessment tests have been presented to help in anticipating a difficult airway. We conducted this study to compare five methods in prediction of difficult laryngoscopy: Neck circumference (NC), NC to thyromental distance ratio (NC/TMD), the ratio of height to thyromental distance (RHTMD), upper lip bite test (ULBT) and Mallampati test (MMT). These five methods are the most commonly used ones and have different powers for it. It was not clear which of these methods predicts difficult laryngoscopy better.

Materials and Methods:

Six hundred consecutive patients participated in this study. NC, NC/TMD and RHTMD were measured, and ULBT and MMT were performed and recorded. The laryngoscopy view was graded according to Cormack and Lehane's scale (CLS) and difficult laryngoscopy was defined as CLS grades 3 and 4. Accuracy of tests in predicting difficult laryngoscopy was assessed using the area under a receiver-operating characteristic curve.

Results:

The area under the curve in ULBT and RHTMD were significantly larger than that in TMD, NC and MMT. No statistically significant differences were noted between TMD, NC and MMT (all P > 0.05) (ULBT = RHTMD > NC/TMD > TMD = NC = MMT). RHTMD (>22.7 cm) exhibited the highest sensitivity (sensitivity = 64.77, 95% confidence interval [CI]: 53.9–74.7) and the most specific test was ULBT (specificity = 99.41%, 95% CI: 98.3–99.9).

Conclusion:

RHTMD and ULBT as simple preoperative bedside tests have a higher level of accuracy compared to NC/TMD, TMD, NC, MMT in predicting a difficult airway.

What We All Should Know About Our Patient's Airway: Difficult Airway Communications, Database Registries, and Reporting Systems Registries

Documentation and dissemination of patient information characterizing a difficult airway encounter is a critical safety link between past, present, and future health care providers. Effective communication of the nature of the difficulty encountered and the airway management techniques used consists of documentation in the patient's medical record for concurrent care providers and dissemination of that information to the patient and future providers for use during subsequent episodes of care. Significant progress has been made with developing national and international electronic patient record systems and airway databases, but full integration has yet to be achieved.

Multiple failed intubation attempts are associated with decreased success rates on the first rescue intubation in the emergency department: a retrospective analysis of multicentre observational data

Background

Although the international guidelines emphasize early and systematic use of rescue intubation techniques, there is little evidence to support this notion. We aimed to test the hypothesis that preceding multiple failed intubation attempts are associated with a decreased success rate on the first rescue intubation in emergency departments (EDs).

Methods

We analysed data from two multicentre prospective registries designed to characterize current ED airway management in Japan between April 2010 and June 2013. All patients who underwent a rescue intubation after a failed attempt or a series of failed attempts were included for the analysis. Multiple failed intubation attempts were defined as ≥2 consecutive failed intubation attempts before a rescue intubation. Primary outcome measure was success rate on the first rescue intubation attempt.

Results

Of 6,273 consecutive patients, 1,151 underwent a rescue intubation. The success rate on the first rescue intubation attempt declined as the number of preceding failed intubation attempts increased (81% [95% CI, 79%-84%] after one failed attempt; 71% [95% CI, 66%-76%] after two failed attempts; 67% [95% CI, 55%-78%] after three or more failed attempts; P_trend <0.001). In the multivariable analysis adjusting for age, sex, principal indication, change in methods, devices, and intubator specialty, and clustering of patients within EDs, success rate on the first rescue intubation after two failed attempts was significantly lower (OR, 0.56; 95% CI, 0.41-0.77) compared to that after one failed attempt. Similarly, success rate on the first rescue intubation attempt after three or more failed attempts was significantly lower (OR, 0.49; 95% CI, 0.25-0.94) compared to that after one failed attempt.

Conclusion

Preceding multiple failed intubation attempts was independently associated with a decreased success rate on the first rescue intubation in the ED.

The accuracy of locating the cricothyroid membrane by palpation - an intergender study

Background

The cricothyroid membrane (CTM) is the recommended site of access to the airway during cricothyrotomy to provide emergency oxygenation. We sought to compare the ability of physicians to correctly identify the CTM in male and female patients.

Methods

In a prospective observational study, anaesthetists were asked to locate the CTM by palpation which was then identified using ultrasound and the distance between the actual and estimated margin of the CTM was measured. Participants assessed the ease of CTM palpation using a visual analog scale. In a second series, the angulation of the posterior junction of the thyroid laminae was measured using ultrasound.

Results

23 anaesthetists and 44 subjects participated. A total of 36 assessments were carried out in each gender. Incorrect identification of the CTM was more common in females (29/36 vs. 11/36, P < 0.001) and the distance from the CTM in the vertical plane was greater (11.0 [6.5–20.0] vs. 0.0 [0.0–10.0] mm, P < 0.001). In females distance from the CTM correlated positively with neck circumference (P = 0.005) and BMI (P = 0.00005) and negatively with subject height (P = 0.01). Posterior thyroid cartilage angulation was greater in females (118.6 ± 9.4° vs. 95.9 ± 12.9°, P = 0.02) and was lower in patients with correctly identified CTMs (100.0 ± 14.9° vs. 115.6 ± 15.9°, P = 0.02). VRS palpation correlated with decreased posterior thyroid cartilage angulation (P = 0.04).

Conclusions

CTM localisation is more difficult in female subjects irrespective of body habitus. It may be prudent to localize this structure by additional means (e.g. ultrasound) in advance of any airway manoeuvres or to modify the cricothyrotomy technique in the event that it is necessary in an emergency.

Tracheal intubation with a flexible fibreoptic scope or the McGrath videolaryngoscope in simulated difficult airway scenarios: a randomised controlled manikin study

BACKGROUND

Flexible fibreoptic endoscopic (FFE) intubation is considered the 'gold-standard' when difficult airway management is anticipated. Several videolaryngoscopes have been developed to facilitate intubation by laryngoscopy.

OBJECTIVE

The aim of the study was to compare the performance of the McGrath series 5 videolaryngoscope (McGrath videolaryngoscope) and the FFE for tracheal intubation in manikins with a simulated difficult airway, hypothesizing that the McGrath videolaryngoscope intubation would prove faster than FFE intubation.

DESIGN

A randomised controlled study.

SETTING

The Danish Institute for medical simulation between December 2009 and June 2010.

PARTICIPANTS

Twenty-eight anaesthesia residents participating in the Danish mandatory 3-day airway management course.

INTERVENTIONS

All participants received instructions and training in the use of the McGrath videolaryngoscope and FFE. The participants then performed tracheal intubation on a SimMan manikin once with the McGrath videolaryngoscope and once with the FFE in three difficult airway scenarios: (1) pharyngeal obstruction; (2) pharyngeal obstruction and cervical rigidity; (3) tongue oedema.

MAIN OUTCOME MEASURES

We measured successful intubations, defined as intubation within 120  s, and time to tracheal intubation.

RESULTS

The trachea was intubated within 120  s with the McGrath videolaryngoscope in 25 out of 27 (93%), 25 out of 28 (89%) and 18 out of 28 (64%) occasions compared with 11 out of 28 (40%), 11 out of 28 (40%) and 16 out of 28 (57%) with the FFE in scenarios (1), (2) and (3), respectively. Time to tracheal intubation was shorter with the McGrath videolaryngoscope in scenarios (1) and (2) than with the FFE (Wilcoxon signed rank sum test, P < 0.0001).

CONCLUSION

The McGrath videolaryngoscope is a valuable device with higher success rate and a quicker performance in simulated difficult airways. In patients, videolaryngoscopy may have a role in difficult airway algorithms, but the optimal device has yet to be found.

A review of video laryngoscopes relevant to the intensive care unit

The incidence of difficult direct intubation in the intensive care unit (ICU) is estimated to be as high as 20%. Recent advances in video-technology have led to the development of video laryngoscopes as new intubation devices to assist in difficult airway management. Clinical studies indicate superiority of video laryngoscopes relative to conventional direct laryngoscopy in selected patients. They are therefore an important addition to the armamentarium of any clinician performing endotracheal intubation. We present a practical review of commonly available video laryngoscopes with respect to design, clinical efficacy, and safety aspects relevant to their use in the ICU.

Anatomic features of the neck as predictive markers of difficult direct laryngoscopy in men and women: A prospective study

BACKGROUND AND AIMS

Difficult airway assessment is based on various anatomic parameters of upper airway, much of it being concentrated on oral cavity and the pharyngeal structures. The diagnostic value of tests based on neck anatomy in predicting difficult laryngoscopy was assessed in this prospective, open cohort study.

METHODS

We studied 341 adult patients scheduled to receive general anaesthesia. Thyromental distance (TMD), sternomental distance (STMD), ratio of height to thyromental distance (RHTMD) and neck circumference (NC) were measured pre-operatively. The laryngoscopic view was classified according to the Cormack-Lehane Grade (1-4). Difficult laryngoscopy was defined as Cormack-Lehane Grade 3 or 4. The optimal cut-off points for each variable were identified by using receiver operating characteristic analysis. Sensitivity, specificity and positive predictive value and negative predictive value (NPV) were calculated for each test. Multivariate analysis with logistic regression, including all variables, was used to create a predictive model. Comparisons between genders were also performed.

RESULTS

Laryngoscopy was difficult in 12.6% of the patients. The cut-off values were: TMD ≤7 cm, STMD ≤15 cm, RHTMD >18.4 and NC >37.5 cm. The RHTMD had the highest sensitivity (88.4%) and NPV (95.2%), while TMD had the highest specificity (83.9%). The area under curve (AUC) for the TMD, STMD, RHTMD and NC was 0.63, 0.64, 0.62 and 0.54, respectively. The predictive model exhibited a higher and statistically significant diagnostic accuracy (AUC: 0.68, P < 0.001). Gender-specific cut-off points improved the predictive accuracy of NC in women (AUC: 0.65).

CONCLUSIONS

The TMD, STMD, RHTMD and NC were found to be poor single predictors of difficult laryngoscopy, while a model including all four variables had a significant predictive accuracy. Among the studied tests, gender-specific cut-off points should be used for NC.

Is there a correlation of sonographic measurements of true vocal cords with gender or body mass indices in normal healthy volunteers?

Background:

Ultrasound is a readily available, non-invasive technique to visualize airway dimensions at the patient's bedside and possibly predict difficult airways before invasively looking; however, it has rarely been used for emergency investigation of the larynx. There is limited literature on the sonographic measurements of true vocal cords in adults and normal parameters must be established before abnormal parameters can be accurately identified.

Objectives:

The primary objective of the following study is to identify the normal sonographic values of human true vocal cords in an adult population. A secondary objective is to determine if there is a difference in true vocal cord measurements in people with different body mass indices (BMIs). The third objective was to determine if there was a statistical difference in the measurements for both genders.

Materials and Methods:

True vocal cord measurements were obtained in healthy volunteers by ultrasound fellowship trained emergency medicine physicians using a high frequency linear transducer orientated transversely across the anterior surface of the neck at the level of the thyroid cartilage. The width of the true vocal cord was measured perpendicularly to the length of the cord at its mid-portion. This method was duplicated from a previous study to create a standard of measurement acquisition.

Results:

A total of 38 subjects were enrolled. The study demonstrated no correlation between vocal cord measurements and patient's characteristics of height, weight, or BMI's. When accounting for vocal cord measurements by gender, males had larger BMI's and larger vocal cord measurements compared with females subjects with a statistically significant different in right vocal cord measurements for females compared with male subjects.

Conclusion:

No correlation was seen between vocal cord measurements and person's BMIs. In the study group of normal volunteers, there was a difference in size between the male and female vocal cord size.

The use of VivaSight™ single lumen endotracheal tube in morbidly obese patients undergoing laparoscopic sleeve gastrectomy

Background

The population of obese patients is progressively growing and bariatric operations are becoming increasingly common. Morbidly obese patients require special anesthetic care and are often considered to be difficult to ventilate and intubate. The VivaSight™ Single Lumen tube is an endotracheal tube with a camera embedded in its tip. The view from the tip appears continuously on a monitor in the anesthesiologist's vicinity. The aim of this study was to assess the VivaSight™ in comparison with conventional endotracheal tube as an aid in the intubation and surveillance of tube position during surgery of obese patients.

Methods

This is a prospective study of 72 adult obese patients who underwent laparoscopic sleeve gastrectomy. The patients were randomly assigned to be intubated by either the VivaSight™ (40 patients, test group) or a conventional endotracheal tube (32 patients, control group). Data on the patients, the pre-operative airway evaluation, the endotracheal intubation and the post-operative outcome were collected and compared.

Results

The Mallampati scores were significantly higher in the test group than in the control group. Endotracheal intubation took 29 ± 10 and 24 ± 8 seconds using the VivaSight™ and a conventional tube respectively (p = 0.02). Three of the patients in the control group, while none of those in the test group, had soft tissue injury (p < 0.05).

Conclusion

We found the VivaSight™ SL to be helpful in the endotracheal intubation and continuous surveillance of tube position in morbidly obese patients undergoing laparoscopic sleeve gastrectomy.

Emergency gum elastic bougie-assisted tracheal intubation in four patients with upper airway distortion

PURPOSE

The gum elastic bougie (GEB) has been in use for a long time and allows tracheal intubation in most cases of difficult direct laryngoscopy. Use of the GEB when anatomical landmarks of the upper airway are not recognizable has not been reported. We describe our experience of airway management with the GEB in cases of severe upper airway distortion.

CLINICAL FEATURES

Four patients with severe respiratory distress caused by upper airway distortion secondary to various non-malignant causes were managed with the GEB. For these four patients, a rapid sequence induction of anesthesia was performed with a surgeon present during the procedure. The GEB was used as the initial intubating technique in all cases and allowed a rapid and successful tracheal intubation in spite of non-recognizable anatomical structures. The distal hold-up feeling after GEB insertion confirmed, in all cases, the correct intratracheal position of the GEB.

CONCLUSION

The GEB can be a valuable tool in cases of difficult airway management caused by upper airway distortion. The lack of visualization of normal pharyngeal structures did not prevent the successful insertion of the GEB in the trachea in the four patients reported.

Making endotracheal intubation easy and successful, particularly in unexpected difficult airway

Background:

Difficult intubation, most often due to poor view of the vocal cords on laryngoscopy is an intermittent and often challenging problem for clinically practicing anesthesiologists, maxillofacial surgeons, ear nose, and throat (ENT), emergency, and critical care physicians.

Purpose:

We present a new approach for facilitating difficult intubation and evaluate its efficacy in a retrospective observational study.

Settings and Design:

Operating room, emergency department, intensive care unit (ICU), retrospective observational study.

Materials and Methods:

A semirigid 5.6 Rüsch tracheal tube introducer (bougie) with its soft tip protruding at least 6 cm (=4 digits) beyond the distal end of the tube was used. After its insertion through the larynx under laryngoscopy, the tube was gently advanced upon rotation at 360° clockwise.

Statistical Analysis:

Descriptive.

Results:

Anesthesia services were analyzed on 10,363 patients over 12 months. In 2453 patients (23.7%) (Group A) intubated in the usual way, difficulties were encountered in 63 patients (2.6%). They were managed either with tube rotation technique (n = 60) or Bonfils endoscope (n = 3). In contrast, 2807 patients (27.1%) (Group B) were intubated using tube rotation technique with introducer. Difficult intubations occurred only in three patients (0.11%) who could be managed with tube rotation by experienced consultant anesthesiologists.

Conclusions:

The tube rotation technique for intubation was introduced during the Gulf War and has been practiced for the past 19 years without any obvious damage to the trachea in Germany. However, it should be used only by physicians being well familiar with this technique. In addition, well designed controlled studies are needed.