Airway Scope for difficult intubation

Three-day tracheal intubation manikin training for novice doctors using Macintosh laryngoscope, McGRATH MAC videolaryngoscope and Pentax AirwayScope

BACKGROUND

We compared the intubation skills obtained by novice doctors following training using 3 instruments, the conventional Macintosh laryngoscope (Mac) and 2 types of indirect video-laryngoscopes (McGrathTM-MAC: McGrath (McG) and AirwayScope (AWS)), to determine the most appropriate instrument for novice doctors to acquire intubation skills, especially focusing on visual confirmation of vocal cords, during a 3-day intensive manikin training program.

METHODS

Fifteen novice doctors who did not have sufficient experience in endotracheal intubation (ETI) and consented to participate in this study were included. We used AirSim and AMT (Airway management Trainer) manikins. First, an experienced anesthesiologist instructed the trainees on using the 3 instruments for a few minutes. Then, after familiarizing themselves with each device for 10 minutes, the participants attempted ETI on the 2 manikins with the 3 devices used in random order. Intubations with each device were practiced and performed for 3 successive days. We assessed the percentage of glottic opening (POGO) score, successful intubation rate and tracheal intubation time for each participant, with each device, and on each day.

RESULTS

In the first manikin, AirSim, POGO scores in the McG and AWS groups were significantly higher than those in the Mac group on all 3 days (P < .0001). The number of intubation failures in the Mac group decreased from 2 cases on day 1, to 1 case on day 2 and zero cases on day 3. There were no failures in the McG and AWS groups on any of the days. With the second manikin, AMT, POGO scores in the Mac group were significantly lower than those in the McG and AWS groups on all 3 days. There were no intubation failures in the AWS group on all 3 days. In the Mac group, the number of intubation failures decreased from 3 on day 1, to 2 on day 2 and zero failures on day 3. In the McG group, there were only 3 failures on day 1.

CONCLUSION

The 2 types of indirect video-laryngoscopes (McGRATH and AirwayScope) were demonstrated to be suitable instruments for novice doctors to achieve higher POGO scores in a 3-day intensive ETI training.

Endotrol tracheal tube and McGrath Mac are an effective combination for oral tracheal intubation

Background

Tracheal intubation using the 2^nd-generation video laryngoscope sometimes cannot be performed easily because there is no functional endotracheal tube (ETT) guide. Therefore, a rigid stylet is often required during tracheal intubation. The Endotrol^® tracheal tube (Endotrol) is a single use ETT that whole tube can be bent and slide easily into the trachea. We studied the intubation ease of a combination of an Endtrol and the McGrath^® video laryngoscope (McGrath), which is one of the 2^nd-generation video laryngoscopes.

Methods

Sixty adult patients under general anesthesia were randomized into three groups: Group A: McGrath with Endotrol, B: McGrath with a rigid stylet attached ETT, and C: Direct laryngoscope with an ETT. The primary outcome measure was intubation time. Secondary outcomes were the number of insertion attempts required and the number of patients who complained of a sore throat after the procedure. The level of significance for each test was set at P < 0.05.

Results

Intubation time (median [range] in seconds) was shorter in Group A (32 [27-54]) than Group B (37 [27-49]) and C (37 [27-50]) (P = 0.01 for both comparison). There was no significant difference among groups for the number of insertion attempts required. The number of patients with a sore throat was lower in Group A (0) than Group B (5) and C (6) (P = 0.02 and 0.01, respectively).

Conclusion

A combination of an Endtrol and a McGrath is effective for shortening intubation time and avoiding sore throats.

Efficacy of Pentax airway scope versus Macintosh laryngoscope when used by novice personnel: A prospective randomized controlled study

Objective

To determine whether intubation education using the Pentax Airway Scope (AWS) in normal airways is more useful than direct laryngoscopy (Macintosh laryngoscope) in novice personnel.

Methods

Eleven intern doctors without intubation experience performed 60 sequential intubations with each device on a manikin and 10 sequential intubations in adult patients. The time required for successful intubation, percentage of glottic opening (POGO) score, number of intubation attempts, and number of dental injuries were analyzed for each intubation technique.

Results

The mean (standard deviation) time required for successful intubation decreased as the number of intubations increased and was significantly shorter with the Pentax AWS than direct laryngoscope [22.6 (7.3) vs. 29.6 (10.0) and 33.0 (8.0) vs. 44.7 (5.6) s, respectively] in both the manikin and clinical studies. The Pentax AWS was also associated with higher POGO scores than the direct laryngoscope [81.7 (8.9) vs. 55.1 (13.2) and 80.9 (9.7) vs. 49.6 (16.5), respectively] and fewer intubation attempts. Fewer dental injuries occurred with the Pentax AWS in the manikin study.

Conclusions

Novices performed intubation more rapidly and easily with an improved laryngeal view using the Pentax AWS. We suggest that intubation education with video laryngoscopy should be mandatory along with direct laryngoscope training.

The difficult airway with recommendations for management--part 1--difficult tracheal intubation encountered in an unconscious/induced patient

Background

Previously active in the mid-1990s, the Canadian Airway Focus Group (CAFG) studied the unanticipated difficult airway and made recommendations on management in a 1998 publication. The CAFG has since reconvened to examine more recent scientific literature on airway management. The Focus Group’s mandate for this article was to arrive at updated practice recommendations for management of the unconscious/induced patient in whom difficult or failed tracheal intubation is encountered.

Methods

Nineteen clinicians with backgrounds in anesthesia, emergency medicine, and intensive care joined this iteration of the CAFG. Each member was assigned topics and conducted reviews of Medline, EMBASE, and Cochrane databases. Results were presented and discussed during multiple teleconferences and two face-to-face meetings. When appropriate, evidence- or consensus-based recommendations were made together with assigned levels of evidence modelled after previously published criteria.

Conclusions

The clinician must be aware of the potential for harm to the patient that can occur with multiple attempts at tracheal intubation. This likelihood can be minimized by moving early from an unsuccessful primary intubation technique to an alternative “Plan B” technique if oxygenation by face mask or ventilation using a supraglottic device is non-problematic. Irrespective of the technique(s) used, failure to achieve successful tracheal intubation in a maximum of three attempts defines failed tracheal intubation and signals the need to engage an exit strategy. Failure to oxygenate by face mask or supraglottic device ventilation occurring in conjunction with failed tracheal intubation defines a failed oxygenation, “cannot intubate, cannot oxygenate” situation. Cricothyrotomy must then be undertaken without delay, although if not already tried, an expedited and concurrent attempt can be made to place a supraglottic device.

Video Laryngoscopy in the Prehospital Setting

In the prehospital setting, the emergency care provider must anticipate that some patients will manifest with difficult airways. The use of video laryngoscopy to secure an airway in the prehospital setting has not been explored widely, but has the potential to be a useful tool. This article briefly reviews some of the major video laryngoscopes on the market and their usefulness in the prehospital setting. Studies and case reports indicate that the video laryngoscope is a promising device for emergency intubation, and it has been predicted that, in the future, video laryngoscopy will dominate the field of emergency airway management.

Direct laryngoscopy always should be retained as a primary skill; however, the video laryngoscope has the potential to be a good primary choice for the patient with potential cervical spine injuries or limited jaw or spine mobility, and in the difficult-to-access patient.The role of video laryngoscopes in securing an airway in head and neck trauma victims in the prehospital setting has yet to be determined, but offers interesting possibilities. Further clinical studies are necessary to evaluate its role in airway management by prehospital emergency medical services.

Haemodynamic response to endotracheal intubation in coronary artery disease: Direct versus video laryngoscopy

Endotracheal intubation involving conventional laryngoscopy elicits a haemodynamic response associated with increased heart and blood pressure. The study was aimed to see if video laryngoscopy and endotracheal intubation has any advantages over conventional laryngoscopy and endotracheal intubation in patients with coronary artery disease. Thirty patients suffering from coronary artery disease scheduled for elective coronary artery bypass grafting (CABG) were studied. The patients were randomly allocated to undergo either conventional laryngoscopy (group A) or video laryngoscopy (group B). The time taken to perform endotracheal intubation and haemodynamic changes associated with intubation were noted in both the groups at different time points. The duration of laryngoscopy and intubation was significantly longer in group B (video laryngoscopy) when compared to group A patients. However, haemodynamic changes were no different between the groups. There were no events of myocardial ischaemia as monitored by surface electrocardiography during the study period in either of the groups. In conclusion, video laryngoscopy did not provide any benefit in terms of haemodynamic response to laryngoscopy and intubation in patients undergoing primary CABG with a Mallampatti grade of <2.

Evaluation of the Pentax-AWS(®) and the Macintosh laryngoscope in difficult intubation: a manikin study

BACKGROUND

The Pentax-AWS (AWS(®)), a new video laryngoscope, has been shown to be useful in cases of difficult intubation. We hypothesized that the AWS(®) would be more useful in the settings of a narrow upper airway than the Macintosh laryngoscope. We compared each device in simulated scenarios of representative difficulty of tracheal intubation using a manikin. The primary endpoint was the rate of successful intubation.

METHODS

With each device, 23 anesthesiologists performed tracheal intubation in a SimMan(®) manikin in the following scenarios: (1) normal airway, (2) tongue edema, (3) cervical spine rigidity, (4) pharyngeal obstruction, (5) jaw trismus, (6) tongue edema with pharyngeal obstruction. The intubation time and success rate were measured. Each participant was asked to rate the difficulty of intubation (1=very easy; 5=very difficult).

RESULTS

In the scenarios of tongue edema and tongue edema with pharyngeal obstruction, the AWS(®) yielded a higher success rate (100% vs. 34.8%; P<0.001, 65.2% vs. 21.7%; P=0.006), a shorter intubation time [14.6 (7.0) vs. 33.4 (13.0) s; P<0.001, 24.5 (12.0) vs. 37.6 (11.9); P=0.047; mean (standard deviation)], and a lower difficulty score [2 (1-4) vs. 5 (1-5); P<0.001, 4 (2-5) vs. 5 (3-5); P<0.001; median (range)], compared with the Macintosh laryngoscope.

CONCLUSION

The AWS(®) has an advantage over the Macintosh laryngoscope in simulated tongue edema and tongue edema with pharyngeal obstruction. Further studies in a clinical setting are necessary to confirm these findings.

Effect of cardiopulmonary resuscitation on intubation using a Macintosh laryngoscope, the AirWay Scope, and the gum elastic bougie: A manikin study

BACKGROUND

Physicians could encounter difficult intubation during cardiopulmonary resuscitation (CPR) in trauma patients due to the patient's movement from continuous chest compression and to cervical stabilisation. Therefore, first, we evaluated the impact of chest compression with or without cervical stabilisation on intubation with a Macintosh laryngoscope. Next, we compared difficulty in intubation among the Macintosh laryngoscope, AirWay Scope (AWS), and gum elastic bougie (GEB) with the Macintosh laryngoscope in three simulated CPR scenarios in a randomised, controlled, cross-over study design.

METHODS

Twenty-three anaesthetists intubated the trachea of a manikin (ALS Skill Master, Laerdal Medical Japan, Tokyo, Japan) using the Macintosh laryngoscope, AWS, and GEB in the control scenario, chest compression scenario, and chest compression with cervical stabilisation scenario. Difficulty in intubation was rated on a 5-point scale and the intubation time was measured.

RESULTS

Continuous chest compression increased difficulty in intubation with the Macintosh laryngoscope, compared with the control scenario. Concurrent application of cervical stabilisation further increased the difficulty, compared with application of chest compression alone. Of the three devices compared, the AWS facilitated the easiest intubation, and the GEB facilitated the second-easiest intubation in all scenarios, though the intubation time was slightly longer with the GEB than with other devices.

CONCLUSION

CPR employing continuous chest compression with or without cervical stabilisation caused difficult intubation with the Macintosh laryngoscope. The AWS and GEB facilitated the easiest and second-easiest intubation, respectively, even during CPR employing continuous chest compression with or without cervical stabilisation in a manikin.

Comparison of the Airway Scope and Macintosh laryngoscope with in-line cervical stabilization by the semisolid neck collar: manikin study

BACKGROUND

The usefulness of Airway Scope (AWS) and Macintosh direct laryngoscope (ML) for patients with trauma requiring intubation with in-line cervical stabilization for protection of the cervical spine was compared.

METHODS

Thirty-three residents performed orotracheal intubation using ML and AWS in an intubation model with in-line cervical stabilization. The tracheal intubation success rate, time required for tracheal intubation, and number of trials of inserting the tracheal tube into the trachea were measured in individual residents.

RESULTS

Two residents inserted the tube into the esophagus using ML (success rate: 93.9%), but all residents succeeded in tracheal intubation using AWS (success rate: 100%) (p = 0.492). The time required for intubation was similar using AWS and ML (15 seconds vs. 20 seconds, p = 0.261). The number of trials using AWS was significantly lower (2.0 times vs. 1.0 times, p = 0.001).

CONCLUSION

The usefulness of AWS may be comparable with or greater than that of ML for oral intubation in trauma patients with in-line cervical stabilization.

Tracheal intubation with the PENTAX-AWS (airway scope) reduces changes of hemodynamic responses and bispectral index scores compared with the Macintosh laryngoscope

The PENTAX-AWS, a novel video laryngoscope, allows indirect visualization of the vocal cords on a color monitor display and enables tracheal intubation without upward lifting force required to expose the glottis. This study compared hemodynamic changes, bispectral index scores, and postoperative sore throat before and after laryngoscopy between the Macintosh laryngoscope and the airway scope (AWS). Forty patients (American Society of Anesthesiologists I-II), randomly assigned to either the Macintosh group (n=20 each) or AWS group, were enrolled in this study. After induction with fentanyl (0.001 mg/kg), propofol (1.5 mg/kg), and vecuronium (0.1 mg/kg), tracheal intubation was performed. Hemodynamic parameters were compared before and after laryngoscopy. Patients were assessed for postoperative sore throat at 24 hours after extubation. No significant differences in patient characteristics were observed between groups. Significant increases in both systolic blood pressure (P<0.05 vs. baseline) and heart rate (P<0.001 vs. baseline) after laryngoscopy were seen using the Macintosh blade, whereas the AWS provided no increases in either parameter. The AWS also caused a lesser increase in bispectral index (P<0.05 vs. Macintosh group). Postoperative sore throat was observed in both groups (2 out of 20 in AWS and 6 out of 20 in Macintosh), although this difference did not reach statistically significant level (P=0.23). In conclusion, the AWS offers a reduced degree of hemodynamic stimulation compared with the Macintosh laryngoscope, suggesting that tracheal intubation with the AWS is advantageous to prevent hypertension after laryngoscopy in neurosurgical patients.

Combination of Airway Scope and bougie for a full-stomach patient with difficult intubation caused by unanticipated anatomical factors and cricoid pressure

The Airway Scope, one of the newest video-laryngoscopes, provides an excellent view of the larynx on a built-in monitor screen. Difficulty in introducing an endotracheal tube into the laryngeal aperture may occur, even though the aperture is visible. The bougie may solve this difficulty because its angulated tip can be controlled in a desired direction. The successful use of the bougie along with the Airway Scope in a full-stomach patient with a difficult airway is presented.

Tracheal intubation by non-anesthesia residents using the Pentax-AWS airway scope and Macintosh laryngoscope

STUDY OBJECTIVE

To evaluate the performance of the Pentax-AWS airway scope for tracheal intubation compared with the Macintosh laryngoscope by non-anesthesia residents.

DESIGN

Prospective, randomized, cohort study.

SETTING

University-affiliated hospital.

PATIENTS

520 patients who underwent tracheal intubation for general anesthesia.

INTERVENTIONS

48 non-anesthesia residents performed tracheal intubation using either the Pentax-AWS or the Macintosh laryngoscope.

MEASUREMENTS

Time to complete tracheal intubation, number of attempts until successful intubation, and number of intubations of the esophagus were recorded.

RESULTS

Time to secure the airway (sec; mean +/- SD) was shorter with the Pentax-AWS than with the Macintosh laryngoscope (44 +/- 19 vs. 71 +/- 44 sec; P < 0.001). Of the 264 tracheal intubations with the Pentax-AWS, 239 (91%) were completed within 60 seconds, while only 148 (58%) of the 256 tracheal intubations performed with the Macintosh laryngoscope were completed within the same period. The rate of successful intubations on the first attempt was higher with the Pentax-AWS than the Macintosh laryngoscope (P < 0.001). No esophageal intubation was experienced with the Pentax-AWS approach, while 18 occurred with the Macintosh laryngoscope (P < 0.001).

CONCLUSION

The Pentax-AWS appears to require less operator skill than the Macintosh laryngoscope. Use of the Pentax-AWS may reduce the time to secure the airway and the incidence of failed tracheal intubation by non-anesthesia residents.

Airway Scope: early clinical experience in 405 patients

The Airway Scope (Pentax, Tokyo, Japan) is a new device used for tracheal intubation. It allows visualization of the glottis through a non-line-of sight view. The aim of the present study was to evaluate the suitability of this device for the tracheal intubation of surgical patients. In this prospective study, the Airway Scope was used for the endotracheal intubation of 405 patients by 74 airway operators. The Airway Scope allowed visualization of the glottis in all 405 patients, including those with a Cormack-Lehane view of grade III (n = 15) or grade IV (n = 1) on Macintosh laryngoscopy. All tracheal intubations using the Airway Scope were successful. The mean time to complete tracheal intubation was 42.4 +/- 19.7 s (+/-SD; range, 13-192 s). No dental damage was encountered, though minor mucosal injury caused by the blade was experienced in 2 patients. The Airway Scope consistently permitted a better intubation environment. With its potential advantages, the Airway Scope could be an effective aid to airway management in surgical patients.

Pentax-AWS, a new videolaryngoscope, is more effective than the Macintosh laryngoscope for tracheal intubation in patients with restricted neck movements: a randomized comparative study

BACKGROUND

We studied whether laryngoscopy and tracheal intubation were easier when using the Pentax-AWS (Tokyo, Japan), a new videolaryngoscope, than when applying the Macintosh laryngoscope, during manual in-line neck stabilization.

METHODS

In 203 anaesthetized patients with manual in-line neck stabilization, we inserted the Pentax-AWS and a Macintosh laryngoscope, in turn, and recorded the view of the glottis and time taken to laryngoscopy. The success rate of tracheal intubation (within 120 s) and time to intubation were also recorded.

RESULTS

The view of the glottis was significantly better with the Pentax-AWS than with the Macintosh laryngoscope (P<0.001). For the Macintosh laryngoscope, the view was obscured in 22 of 203 patients (11%) (Grade 3 in 21 patients and Grade 4 in one patient), whereas for the Pentax-AWS, the glottis was always clearly seen (Grade 1). Time taken to see the glottis with the Pentax-AWS [mean (sd): 6.0 (3.1) s] was significantly shorter than with the Macintosh laryngoscope [11.0 (5.0) s] (95% CI for difference: 4-6 s). The success rate of tracheal intubation with the Pentax-AWS (all of 99 patients) was significantly higher than with the Macintosh laryngoscope (93 of 104 patients) (P=0.001). Time taken for intubation was similar between the Macintosh laryngoscope [51 (27) s] and the Pentax-AWS [54 (14) s] (95% CI for difference: -9 to 3 s).

CONCLUSIONS

In patients with stabilized neck, the Pentax-AWS provided a better view of the glottis and a higher success rate of tracheal intubation, compared with the conventional Macintosh laryngoscope.

Tracheal intubation by non-anaesthetist physicians using the Airway Scope

OBJECTIVE

To evaluate the performance of the Airway Scope for tracheal intubation by non-anaesthetist physicians.

METHODS

Under supervision by staff anaesthetists, non-anaesthesia residents performed tracheal intubation using either the Airway Scope (n = 100) or Macintosh laryngoscope (n = 100). The time required for airway instrumentation and the success rate at first attempt were investigated.

RESULTS

The time to secure the airway was shorter with the Airway Scope than with the Macintosh laryngoscope (p<0.001). The success rate at first attempt was higher with the Airway Scope than with the Macintosh laryngoscope (p<0.001).

CONCLUSION

The Airway Scope may reduce the time to secure the airway and the incidence of failed tracheal intubation in novice laryngoscopists.

Evaluation of the Airway Scope, a new video laryngoscope, in tracheal intubation by naive operators: a manikin study

BACKGROUND AND AIM

The Airway Scope (AWS) is a new video laryngoscope. The purpose of this study was to compare the AWS and Macintosh laryngoscopes with regard to their usefulness for beginners in tracheal intubation.

METHODS

Thirty-one nurses with no previous experience of tracheal intubation used each device 10 times to intubate the trachea of a manikin (Laerdal Airway Managemant Trainer, Laerdal, Stavanger, Norway). Intubation correctly completed within 30 s was regarded as successful. The intubation time, success rate, number of esophageal intubations and dental clicks, and subjective evaluation of difficulty of intubation [rated from 1 (extremely easy) to 5 (extremely difficult)] were recorded.

RESULTS

The average intubation time was significantly shorter for AWS than for the Macintosh laryngoscope (16.7 +/- 11.0 s vs. 23.2 +/- 24.9 s; mean +/- standard deviation; P = 0.0297), and the success rate with AWS was significantly greater (91.3% vs. 79.4%; P < 0.001). In the total of 310 intubation attempts for each device, the number of esophageal intubations (0/310 with AWS vs. 20/310 with the Macintosh laryngoscope) and dental clicks (0/310 with AWS vs. 40/310 with the Macintosh laryngoscope) differed significantly (P < 0.001). AWS was rated as easier to use than the Macintosh laryngoscope (P < 0.001).

CONCLUSION

AWS is more useful for beginners as it provides quicker and easier tracheal intubation.

Cervical spine movement during laryngoscopy using the Airway Scope compared with the Macintosh laryngoscope

The Airway Scope is a new rigid laryngoscope. This intubation device provides a non-line-of sight view of the glottis. A non-line-of sight view is expected to cause less movement of the cervical spine during laryngeal visualisation. We compared the degree of cervical spine movement during laryngoscopy with the Airway Scope and conventional direct laryngoscope. Twenty patients requiring general anaesthesia and tracheal intubation were studied. Movements of the cervical spine were measured using radiography in the same patient during laryngoscopy with the Airway Scope and a Macintosh laryngoscope. Cervical spine movement during laryngoscopy with the Airway Scope was 37%, 37% and 68% less than that with the Macintosh laryngoscope at the C0/C1, C1/C2 and C3/C4 motion segments, respectively (p < 0.05). The movement of the atlanto-occipital distance using the Airway Scope was 42% less than that during laryngoscopy using the Macintosh laryngoscope (p < 0.05). Laryngoscopy using the Airway Scope involves less movement of the cervical spine compared to conventional laryngoscopy using the Macintosh laryngoscope.