Engagement of the Median Glossoepiglottic Fold and Laryngeal View During Emergency Department Intubation.

STUDY OBJECTIVE: When using a standard geometry laryngoscope, experts recommend engaging the hyoepiglottic ligament-a ligament deep to the vallecula not visible to the intubator. The median glossoepiglottic fold (hereafter termed midline vallecular fold) is a superficial mucosal structure, visible to the intubator, that lies in the midline of the vallecula. We aimed to determine whether engaging the midline vallecular fold with a standard geometry blade tip during orotracheal intubation improved laryngeal visualization. METHODS: We reviewed laryngoscopic videos from intubations by emergency physicians using standard geometry video laryngoscopes over a 2-year period. Two reviewers watched each video and recorded whether the blade tip engaged the midline vallecular fold (obscured the fold with the blade tip) and the best modified Cormack-Lehane grade and percent of glottic opening obtained. We compared laryngeal views in the presence and absence of fold engagement. RESULTS: We analyzed 183 discrete laryngoscopic episodes, including 113 instances in which the midline vallecular fold was engaged and 70 instances in which the fold was not engaged. The proportion with a Cormack-Lehane grade 1 or 2a was higher with fold engagement (96%) than without (87%) (absolute difference 9% [95% confidence interval (CI) 1 to 18%]). Ordinal logistic regression demonstrated that midline vallecular fold engagement was associated with a more favorable Cormack-Lehane grade (odds ratio 2.1 [95% CI 1.1 to 4.2]). The median percent of glottic opening score was 95% (interquartile range 90 to 100%) with fold engagement and 95% (65 to 100%) without engagement (median difference 0% [95% CI 0 to 5%]). CONCLUSION: Engaging the midline vallecular fold with the laryngoscope blade tip during orotracheal intubation when using a standard geometry blade was associated with improved laryngeal visualization.

The High-Risk Airway.

The high-risk airway is a common presentation and a frequent cause of anxiety for emergency physicians. Preparation and planning are essential to ensure that these challenging situations are managed successfully. Difficult airways typically present as either physiologic or anatomic, each type requiring a specialized approach. Primary physiologic considerations are oxygenation, hemodynamics, and acid-base, whereas anatomic difficulty is overcome using proper positioning and skilled laryngoscopy to ensure success. It is essential to be comfortable performing alternative techniques to address varying presentations. Ultimately, competence in airway management hinges on consistent training, deliberate practice, and a dedication to excellence.

The Cric-Key™ and Cric-Knife™: a combined tube-introducer and scalpel-hook open cricothyrotomy system.

The author describes a cricothyrotomy system that consists of two devices that, packaged together, are labeled the Control-Cric™ system. The Cric-Key™ was invented to verify tracheal location during surgical airway procedures?without the need for visualization, aspiration of air, or reliance on clinicians? fine motor skills. The Cric-Knife™ combines a scalpel with an overlying sliding hook to facilitate a smooth transition from membrane incision to hook insertion and tracheal control. In a recent test versus a traditional open technique, this system had a higher success rate and was faster to implement.

Preoxygenation and prevention of desaturation during emergency airway management.

Patients requiring emergency airway management are at great risk of hypoxemic hypoxia because of primary lung pathology, high metabolic demands, anemia, insufficient respiratory drive, and inability to protect their airway against aspiration. Tracheal intubation is often required before the complete information needed to assess the risk of periprocedural hypoxia is acquired, such as an arterial blood gas level, hemoglobin value, or even a chest radiograph. This article reviews preoxygenation and peri-intubation oxygenation techniques to minimize the risk of critical hypoxia and introduces a risk-stratification approach to emergency tracheal intubation. Techniques reviewed include positioning, preoxygenation and denitrogenation, positive end expiratory pressure devices, and passive apneic oxygenation.

The complexities of tracheal intubation with direct laryngoscopy and alternative intubation devices.

Intubation research on both direct laryngoscopy and alternative intubation devices has focused on laryngeal exposure and not the mechanics of actual endotracheal tube delivery or insertion. Although there are subtleties to tracheal intubation with direct laryngoscopy, the path of tube insertion and the direct line of sight are relatively congruent. With alternative intubation devices, this is not the case. Video or optical elements in alternative intubation devices permit looking around the curve of the tongue, without a direct line of sight to the glottic opening. With these devices, laryngeal exposure is generally the simple part of the procedure, and conversely, tube delivery to the glottic opening and advancement into the trachea are sometimes not straightforward. This article presents the mechanical and optical complexities of endotracheal tube insertion in both direct laryngoscopy and alternative devices. An understanding of these complexities is critical to facilitate rapid tracheal intubation and to minimize unsuccessful attempts.

Use of a battery-operated needle driver for intraosseous access by novice users: skill acquisition with cadavers.

STUDY OBJECTIVES: We determine skill acquisition and performance by using a battery-operated, intraosseous needle driver in cadavers. METHODS: This was a prospective study of the EZ-IO, a battery-operated intraosseous needle driver (Vidacare Corp). Operators received a 5-minute presentation (with 1 insertion demonstration) and then performed 3 tibial insertions on a cadaver. Insertion time was measured from skin placement until stylet removal. Another participant recorded the time and determination of "success." Success required stable bone position and infusion of fluid without extravasation. After testing, operators completed a questionnaire including ease of use (1 to 5; 1=very difficult, 5=very easy), speed versus central line (faster, same, slower), ease of use versus a central line (easier, same, harder), and willingness to use the device in future cardiac arrest situations (yes, maybe, no). RESULTS: Operators included 42 emergency medicine attending physicians, 13 other physicians, 31 emergency medicine residents, and 13 nonphysicians (emergency medical services, etc). None had previous experience with the EZ-IO, and 80 of 99 (80.8%) had never placed an intraosseous needle. Two hundred eighty-nine of 297 insertions (97.3%) were successful. Success rates for the first, second, and third insertion were 96.9%, 94.9%, and 100%, respectively. Median insertion time was 6 seconds (range 3 to 25 seconds), with interquartile range 5 to 8 seconds. The mean ease of use rating was 4.8 (95% confidence interval 4.70 to 4.90). All operators subjectively rated the device faster and easier than a central line; 98 of 99 (99%) expressed willingness to use the device in a cardiac arrest. CONCLUSION: The EZ-IO requires minimal training, is easy to use, and is fast. Skill acquisition is rapid, with a high success rate on the initial insertion after a brief training session and a single demonstration.

Light intensity of curved laryngoscope blades in Philadelphia emergency departments.

STUDY OBJECTIVE: Laryngoscopy and tracheal intubation requires laryngeal exposure and illumination. The objective of this study is to assess variation in laryngoscope lights across different emergency departments (EDs). METHODS: A convenience sample of 3 Mac #4 blade and handle pairs in each of 17 Philadelphia area EDs was tested with a digital light meter to derive the median lux at the distal tip. For each blade tested, we characterized blade design (American, English, or German) and light type (fiber-illuminated versus conventional bulb-on-blade) and measured light-to-tip distance. RESULTS: A total of 50 blades and handle pairs were tested (one ED had only 2 Mac #4 blades). American designs were the most common (38/50), followed by English (6/50) and German (3/50) designs. Three blades had hybrid design features and acrylic light-conducting fibers. Median luminance varied from 11 lux to 5,627 lux. The glass fiber-illuminated blades (n=13) produced greater luminance (median 1,205 lux; interquartile range [IQR] 726 to 2,176 lux) than bulb-on-blade designs (median 689 lux; IQR 290 to 906 lux). German fiber-illuminated blades produced the highest luminance (median 1,937 lux; IQR 1,453 to 3,782 lux). English bulb-on-blade designs produced more luminance (median 915 lux; IQR 745 to 1270 lux) than American (median 689 lux; IQR 269 to 807 lux). German and English blades had shorter light-to-tip distances (median 51 mm and 47 mm, respectively) than American blades (65 mm). CONCLUSION: Curved laryngoscope blades in different EDs have marked variation in light intensity. The contribution of luminance to laryngoscopy performance warrants investigation.

Stylet bend angles and tracheal tube passage using a straight-to-cuff shape.

OBJECTIVES: Malleable stylets improve maneuverability and control during tube insertion, but after passage through the vocal cords the stiffened tracheal tube may impinge on the tracheal rings, preventing passage. The goal of this study was to assess insertion difficulty with styletted tubes of different bend angles. METHODS: Tube passage was assessed with four different bend angles (25 degrees, 35 degrees, 45 degrees, and 60 degrees) using straight-to-cuff-shaped tubes. In two separate airway procedure classes, 16 operators in each class (32 total) placed randomly ordered styletted tubes of the different angles into eight cadavers (16 total). Operators subjectively graded the ease of tube passage as no resistance, some resistance, or impossible to advance. RESULTS: No resistance was reported in 69.1% (177/256) at 25 degrees, in 63.7% (163/256) at 35 degrees, in 39.4% (101/256) at 45 degrees, and in 8.9% (22/256) at 60 degrees. Tube passage was impossible in 2.3% of insertions (6/256) at 25 degrees, in 3.5% (9/256) at 35 degrees, in 11.3% (29/256) at 45 degrees, and in 53.9% (138/256) at 60 degrees. The odds ratios of impossible tube passage for 35 degrees, 45 degrees, and 60 degrees vs. 25 degrees were 1.52 (95% confidence interval [CI] = 0.55 to 4.16), 5.32 (95% CI = 2.22 to 12.71), and 48.72 (95% CI = 21.35 to 111.03), respectively. CONCLUSIONS: Bend angles beyond 35 degrees with straight-to-cuff styletted tracheal tubes increase the risk of difficult and impossible tube passage into the trachea. The authors did not compare different stylet stopping points, stylets of different stiffness, or tracheal tubes with different tip designs, all variables that can affect tube passage.

Design rationale and intended use of a short optical stylet for routine fiberoptic augmentation of emergency laryngoscopy.

Patient safety in emergency airway management has traditionally relied upon prediction of difficult laryngoscopy and alternative intubation devices. Unfortunately, screening tests for difficult laryngoscopy have poor predictive value, and alternative devices are often not suitable for emergency airways. RSI performed with hit or miss repetitive laryngoscopy followed by delayed deployment of rarely used rescue devices is inherently hazardous. First pass success with laryngoscopy should be a benchmark of quality and patient safety in emergency airway management. By making a commitment to minimally modify practice and expand our skill set, fiberoptic augmentation of every laryngoscopy can promote patient safety through the avoidance of repetitive laryngoscopy and esophageal intubation. This article presents the design rationale and intended use of a new short optical stylet for the routine augmentation of emergency direct laryngoscopy.

Laryngeal view during laryngoscopy: a randomized trial comparing cricoid pressure, backward-upward-rightward pressure, and bimanual laryngoscopy.

STUDY OBJECTIVE: External cricoid and thyroid cartilage manipulations are commonly taught to facilitate laryngeal view during intubation. We compare the laryngeal views during laryngoscopy with 4 manipulations (no manipulation, cricoid pressure, backward-upward-rightward pressure [BURP], and bimanual laryngoscopy) to determine the method that optimizes laryngeal view. METHODS: This was a randomized intervention study involving emergency physicians participating in airway training courses from December 2003 to November 2004. Direct laryngoscopies were performed with curved blades on fresh, non-fixed cadavers by using each of the 4 methods. The percentage of glottic opening (POGO), a validated scoring scale, was recorded for each laryngoscopy. Scores for bimanual laryngoscopy were recorded before the assistant applied external pressure. RESULTS: A total of 1,530 sets of comparative laryngoscopies were performed by 104 participants. One thousand one hundred eighteen of 1,530 sets (73%) had POGO scores less than 100 with no manipulation. Compared to no manipulation, mean POGO scores with bimanual laryngoscopy improved by 25 (95% confidence interval [CI] 23 to 27); mean POGO score improvement with cricoid pressure and BURP were 5 (95% CI 3 to 8) and 4 (95% CI 1 to 7), respectively. POGO scores with bimanual laryngoscopy were higher compared to cricoid pressure (mean difference 20, 95% CI 17 to 22) and BURP (mean difference 21, 95% CI 19 to 24). Among laryngoscopies with no manipulation in which the POGO score greater than 0 (n=1,434), laryngeal view worsened in 60 cases (4%, 95% CI 3% to 5%) with bimanual laryngoscopy, in 409 cases (29%, 95% CI 26% to 31%) with cricoid pressure, and in 504 cases (35%, 95% CI 33% to 38%) with BURP. CONCLUSION: Using a cadaver model, we found pressing on the neck during curved blade laryngoscopy greatly affects laryngeal view. Overall, bimanual laryngoscopy improved the view compared to cricoid pressure, BURP, and no manipulation. Cricoid pressure and BURP frequently worsen laryngoscopy. These data suggest bimanual laryngoscopy should be considered when teaching emergency airway management.

Laryngoscopy and morbid obesity: a comparison of the "sniff" and "ramped" positions.

BACKGROUND: The effect of patient position on the view obtained during laryngoscopy was investigated. METHODS: 60 morbidly obese patients undergoing elective bariatric were studied. Patients were randomly assigned into one of two groups. In Group 1, a conventional "sniff" position was obtained by placing a firm 7-cm cushion underneath the patient's head, thus raising the occiput a standard distance from the operating-table while the patient remained supine. In Group 2, a "ramped" position was achieved by arranging blankets underneath the patient's upper body and head until horizontal alignment was achieved between the external auditory meatus and the sternal notch. Following induction of general anesthesia, tracheal intubation was performed using a Video MacIntosh laryngoscope. The laryngoscopy and intubation sequences were recorded onto videotape. Three independent investigators, unaware as to which position the patient had been in at the time of tracheal intubation, then viewed the videotape and assigned a numerical grade to the best laryngeal view obtained. RESULTS: The "ramped" position improved the laryngeal view when compared to a standard "sniff" position, and this difference was statistically significant (P=0.037). CONCLUSION: The "ramped" position is superior to the standard "sniff" position for direct laryngoscopy in morbidly obese patients.

Limitations of difficult airway prediction in patients intubated in the emergency department.

STUDY OBJECTIVE: Physiognomic assessment of difficult laryngoscopy before rapid sequence intubation has been advocated for all emergency department (ED) intubations. The study objectives were to evaluate whether Mallampati scores, thyromental distance, and neck mobility could have been assessed in non-cardiac arrest ED-intubated patients and determine whether such tests would have been feasible in our rapid sequence intubation-associated laryngoscopy failures. METHODS: We retrospectively reviewed 37 months of ED intubations using prospectively collected data from electronic medical records, critical care flow sheets, and a trauma registry. All non-cardiac arrest ED-intubated patients were included for analysis. Mallampati scoring was deemed unobtainable if patients could not follow simple commands. Neck mobility and thyromental measurement were deemed unobtainable with cervical spine precautions. RESULTS: Eight hundred fifty intubations met the inclusion criteria, and 838 patients underwent rapid sequence intubation. Laryngoscopy failed in 3 patients who underwent rapid sequence intubation. Eight patients had awake nasal intubation, and 4 oral intubations were done without rapid sequence intubation. Four hundred fifty-two (53%) patients could not follow simple commands, and cervical spine immobilization was present in 370 (44%) patients. Only 32% of patients could follow simple commands and were not cervical spine immobilized. Among the 3 rapid sequence intubation laryngoscopy failures, no patients were following commands. CONCLUSION: Mallampati scoring, neck mobility testing, and measurement of thyromental distance could have been done in only one third of our non-cardiac arrest ED intubations and in none of the rapid sequence intubation failures. The inability to widely obtain these assessment tools, coupled with the low incidence of failed rapid sequence intubation, indicates limitations to using these screening tests in the ED setting.

Alternating day emergency medicine and anesthesia resident responsibility for management of the trauma airway: a study of laryngoscopy performance and intubation success.

STUDY OBJECTIVE: We compare laryngoscopy performance and overall intubation success in trauma airways when primary airway management alternated between emergency medicine and anesthesia residents on an every-other-day basis. METHODS: Data on all trauma intubations during approximately 3 years were prospectively collected. Primary airway management was assigned to emergency department (ED) residents on even days and anesthesia residents on odd days. Emergency medicine residents intubated patients who arrived without notification or who needed immediate intubation before anesthesia arrived. The study was conducted in an inner-city, Level I trauma center with approximately 50,000 ED patients and 1,800 major trauma cases a year. Main outcomes were success or failure at laryngoscopy and the number of laryngoscopy attempts needed for intubation. RESULTS: Six hundred fifty-eight trauma patients were intubated during the study period. Laryngoscopy was successful in 654 of 656 cases. Two (0.3%) patients underwent cricothyrotomy after failed laryngoscopy, and 2 (0.3%) patients had awake nasal intubation without laryngoscopy. The specific number of laryngoscopy attempts was unknown in 6 cases (3 from each service), resulting in 650 cases for laryngoscopy performance analysis. Overall, 87% of patients were intubated on first attempt, and 3 or more attempts occurred in 2.9% of patients. Laryngoscopy performance by service (broken down by 1, 2, and >or=3 attempts) was as follows: emergency medicine 86.4%, 11%, and 2.6% versus anesthesia 89.7%, 6.7%, and 3.6%. Analysis by service was done by using Wilcoxon Mann-Whitney testing (P=.225). CONCLUSION: There were no differences in laryngoscopy performance and intubation success in trauma airways managed on an every-other-day basis by emergency medicine versus anesthesia residents.