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Biomedical subjects

R M Levitan

Publications and source records attributed to R M Levitan.

13 recordsLinked to original sources
PubMed2005

Initial anatomic investigations of the I-gel airway: a novel supraglottic airway without inflatable cuff.

The I-gel airway is a novel supraglottic airway that uses an anatomically designed mask made of a gel-like thermoplastic elastomer. We studied the positioning and mechanics of this new device in 65 non-embalmed cadavers with 73 endoscopies (eight had repeat insertion), 16 neck dissections, and six neck radiographs. A full view of the glottis (percentage of glottic opening score 100%) occurred in 44/73 insertions, whereas only 3/73 insertions had epiglottis-only views. Including the eight repeat insertions with a different size, a glottic opening score of > 50% was obtained in all 65 cadavers. The mean percentage of glottic opening score for the 73 insertions was 82% (95% confidence interval 75-89%). In each of the neck dissections and radiographs the bowl of the device covered the laryngeal inlet. We found that the I-gel effectively conformed to the perilaryngeal anatomy despite the lack of an inflatable cuff and it consistently achieved proper positioning for supraglottic ventilation.

Epiglottis↗
PubMed2001

Training with video imaging improves the initial intubation success rates of paramedic trainees in an operating room setting.

STUDY OBJECTIVE: Video imaging of intubation as seen by the laryngoscopist has not been a part of traditional instruction methods, and its potential impact on novice intubation success rates has not been evaluated. METHODS: We prospectively tracked the success rates of novice intubators in paramedic classes who were required to watch a 26-minute instructional videotape made with a direct laryngoscopy imaging system (video group). We compared the prospectively obtained intubation success rate of the video group against retrospectively collected data from prior classes of paramedic students (traditional group) in the same training program. All classes received the same didactic airway instruction, same mannequin practice time, same paramedic textbook, and were trained in the same operating room with the same teaching staff. RESULTS: The traditional group (n=113, total attempts 783) had a mean individual intubation success rate of 46.7% (95% confidence interval 42.2% to 51.3%). The video group (n=36, total attempts 102) had a mean individual intubation success rate of 88.1% (95% confidence interval 79.6% to 96.5%). The difference in mean intubation success rates between the 2 groups was 41.4% (95% confidence interval 31.1% to 50.7%, P <.0001). The 2 groups did not differ in respect to age, male sex, or level of education. CONCLUSION: An instructional videotape made with the direct laryngoscopy video system significantly improved the initial success rates of novice intubators in an operating room setting.

Allied Health Personnel↗
PubMed2001

A videographic analysis of laryngeal exposure comparing the articulating laryngoscope and external laryngeal manipulation.

Activation of the articulating laryngoscope and external laryngeal manipulation (ELM) improve laryngeal exposure during direct laryngoscopy. We used a head-mounted direct laryngoscopy imaging system and a previously validated scoring system for assessing laryngeal view (the percentage of glottic opening or POGO score) on 33 adult patients undergoing laryngoscopy. On each patient, we videotaped the initial laryngeal exposure (blade not activated), the view with activation of the blade, and the view with operator-directed external laryngeal manipulation. The video recordings were reviewed and the laryngeal view assessed with POGO scores. POGO scores improved with blade activation in 9/33 (27%) of patients vs 28/33 (85%) of patients with ELM. In nearly half of patients studied (16/33, 48%) POGO scores decreased with blade activation. We conclude that ELM is superior to articulating laryngoscope blade activation in improving POGO scores during laryngoscopy on adult patients in standard sniffing position. Using recordings from a direct laryngoscopy video system, we compared laryngeal views in 33 patients with a special articulating laryngoscope blade to views achieved by external laryngeal manipulation (pressing on the patient's neck). Laryngeal exposure, which is important for placement of tracheal tubes, was better with external laryngeal manipulation.

Adult↗
PubMed2000

Use of the intubating laryngeal mask airway by medical and nonmedical personnel.

The intubating laryngeal mask airway (ILMA) is a newly available device designed to allow for blind endotracheal intubation and treatment of patients with difficult airways. We studied the intubation success rates and speed with initial use of this device on an intubation manikin to determine whether this device might be easily used by trained and untrained personnel. Rapid and successful intubation with a device requiring limited or no training could have widespread implications for both health care providers and laypersons. The study consisted of 2 parts. In part 1, health care providers with intubation experience, health care providers without prior intubation experience, and nonmedical personnel were instructed to enter a room and intubate a manikin using the ILMA. A single page set of schematic directions was provided within the ILMA setup. The main outcomes were the intubation success rate and the time required for successful ventilation and intubation. In part 2, participants were retested after a standardized <60 second device demonstration. The 111 participants in the study included 44 emergency physicians (40%), 21 anesthesiologists (19%), and 46 other medical or nonmedical personnel (41%). On first attempted use of the device, and with no prior training, 59% of all participants successfully intubated the manikin. Attending and resident physicians had an 83% initial success rate. The median time to ventilation was 47 seconds, and the median time from ventilation until intubation was 29 seconds. Following the <60 second demonstration, 108 of 111 (97%) participants achieved success, with the median time to ventilation 18 seconds, and the median time from ventilation until intubation 17 seconds. All attending and resident physicians succeeded in intubation following the demonstration. Success rates on first attempt correlated with level of training, prior intubation experience, and prior LMA use (all P < .001). After a <60 second demonstration, medical and nonmedical personnel with and without prior intubation training can successfully use the ILMA to rapidly establish an airway in a manikin model. The ILMA should be further studied to determine if it may permit endotracheal intubation by first responders, paramedical personnel, and other medical staff with limited or no laryngoscopy skills.

Clinical Competence↗
PubMed1999

Assessment of laryngeal view: percentage of glottic opening score vs Cormack and Lehane grading.

PURPOSE: To examine the intra- and inter-rater reliability of two methods that categorize laryngeal view during direct laryngoscopy, the Cormack-Lehane grading system and a new scale, the percentage of glottic opening (POGO) scale. METHODS: Seven anesthesiologists from the University of Pennsylvania Health System viewed 25 identical pairs of slides of laryngeal views during direct laryngoscopy. Each anesthesiologist rated the 50 slides for both Cormack-Lehane grades and POGO scores. The latter CL replaces grades 1 and 2 C-L grades with a percentage of glottic opening: the POGO score. Inter and intra-physician reliability for the Cormack-Lehane grades were determined using the kappa statistic analysis, comparison of POGO scores was performed using the intraclass correlation coefficients (rI). RESULTS: The POGO score had a better inter and intra-physician reliability than the Cormack-Lehane grading system. The intra-physician reliability for the POGO score was very good with an average interclass rI value of 0.88. The inter-physician score was good with a rI of 0.73. The Cormack-Lehane grading system had excellent intra-physician concordance (average kappa = 0.83.) but the inter-physician reliability was poor (kappa = 0.16.) CONCLUSION: The Cormack-Lehane grading system has very poor inter-physician reliability. The lack of inter-physician reliability with Cormack-Lehane grading calls into question the results of previous studies in which different laryngoscopists used this method to assess laryngeal view. The POGO score appears to have good intra and inter-rater reliability. It has several theoretical advantages and may prove to be more useful for research studies in direct laryngoscopy.

Glottis↗
PubMed1999

Devices for difficult airway management in academic emergency departments: results of a national survey.

STUDY OBJECTIVE: We conducted a national survey of emergency medicine residency program directors to determine which alternative devices were available in their emergency departments for difficult airway management. We also assessed the residency directors' experience in use of these devices. METHODS: After approval was received from the institutional review board at our institution, residency directors were contacted by mail, fax, or phone in October 1997. Alternative intubation devices were defined as devices that do not involve use of a laryngoscope and direct visualization for tracheal tube placement. Alternative ventilation devices were defined as those that do not use a face mask for ventilation. We asked whether the following alternative intubation devices were stocked in their department: a flexible fiberoptic bronchoscope, a rigid fiberoptic device (ie, Bullard, Wu-Scope), a lighted stylet, or a retrograde intubation kit. We also asked about the following alternative ventilation devices: a transtracheal jet ventilation system with a 50-psi oxygen source and control valve, the esophageal tracheal twin-lumen airway device (Combitube), or the laryngeal mask airway. Residency directors were also questioned about their duration of practice, intubation experience, and use of these devices. RESULTS: We obtained information from 95 of 118 (81%) programs. Of 95 programs, 61 (64%) had a fiberoptic bronchoscope, 43 (45%) a retrograde intubation kit, 33 (35%) a lighted stylet, and 6 (.06%) a rigid fiberoptic device. Forty-seven (49%) of the programs reported 2 or more devices, and 20 (21%) reported having no alternative intubation devices. Of 95 programs, 64 (67%) had a transtracheal jet ventilation system, 25 (26%) had the Combitube, and 25 (26%) had the laryngeal mask airway. Thirty-one (33%) programs had at least 2 alternative ventilation devices, and 20 (21%) had none. Ten (11%) programs had no alternative intubating or ventilation devices. Additional information on duration of practice, intubation experience, and actual use of alternative devices was obtained from 83 of the 95 (87%) emergency medicine residency directors contacted. Forty-one (49%) reported never having used an alternative device for intubation. The most commonly used alternative intubation device was the flexible fiberoptic bronchoscope (37%), and the mean number of times any alternative device was used was 7. CONCLUSION: The availability of devices for difficult airway management varies tremendously across emergency medicine residency programs. Only half of residency program directors had any experience with these devices, and among those that reported any experience, they are used rarely.

Airway Obstruction↗
PubMed1998

Assessment of airway visualization: validation of the percentage of glottic opening (POGO) scale.

OBJECTIVE: Research defining optimal methods of intubation has been limited by the lack of a validated outcome measure to assess airway visualization. The objective of this study was to develop a reliable scale for the assessment of airway visualization during endotracheal intubation. METHODS: This prospective study was performed to assess the intra- and interphysician reliabilities of emergency physicians (EPs) for estimating the percentage of glottic opening (POGO) that is visualized during direct laryngoscopy. Using video images of laryngeal views obtained from a commercially available videotape, still slide images were prepared representing glottic openings ranging from 0% to 100%. Five EPs, blinded to study objective, reviewed 25 pairs of airway slides (50 slides total). For each slide, the physicians recorded the POGO and their scores using a modified Cormack-Lehane (MCL) scale, where grade I is a view of the full glottic opening, MCL grade II is a partial view of the glottic opening, and MCL grade III is a view of the epiglottis only. Inter- and intraphysician reliabilities were assessed using the kappa statistic (K) for MCL grade and intraclass correlation coefficient for the POGO scores. RESULTS: For the POGO score, the degree of intrarater reliability was very good, with an intraphysician correlation of 0.85 and an interphysician correlation of 0.74. For the MCL score, the intraphysician concordance had a K of 0.71, and interphysician concordance was also good, with a kappa of 0.59. CONCLUSION: Both the modified version of the Cormack-Lehane grading classification and the POGO score have good interphysician and intraphysician reliabilities. Because the POGO score can distinguish patients with large and small degrees of partial glottic visibility, it might provide a better outcome for assessing the difference between various intubation techniques.

Emergency Medical Services↗