The quickest and easiest endotracheal intubation device in difficult airway for emergency residents: video laryngoscope, the easiest laryngoscope for emergency residents
Correspondence / American Journal of Emergency Medicine 32 (2014) 797–810 807
Martin D. Hoffman, MD Department of Physical Medicine & Rehabilitation Department of Veterans Affairs Northern California Health Care System &
University of California Davis Medical Center Sacramento, CA USA
http://dx.doi.org/10.1016/j.ajem.2014.02.049
Severac M, Orban JC, Leplatois T, et al. A case of near-fatal exercise-associated hyponatremia. Am J Emerg Med (2014). http://dx.doi.org/10.1016/j.ajem.2013. 12.041.
The quickest and easiest endotracheal Intubation device in difficult airway for emergency residents: video laryngoscope, the easiest laryngoscope for
emergency residents?,??
To the Editor,
New video laryngoscope devices have been proposed to improve airway management in the emergency services [1]. However, most of the studies performed compared video laryngoscopes with a standard laryngoscope [2,3].
In this study, we aimed to compare the effectiveness of video
seconds was accepted as a successful intubation time. 7.0 intubation tubes were used, and cuffs were insufflated to 20 cm H2O. Video laryngoscopes and Macintosh laryngoscopes were used on these 3 mannequins: video laryngoscope NM (VNM), video laryngoscope DM1 (VDM1), video laryngoscope DM2 (VDM2), Macintosh laryngo- scope NM (MNM), Macintosh laryngoscope DM1 (MDM1), Macintosh laryngoscope DM2 (MDM2).
vocal cord visualization time length (between start of intubation and visualization of vocal cords) and intubation time length (between start of intubation and visualization of lung ventilation with Ambu mask) were recorded. difficulty of intubation according to the operator and the success of the operator were noted. Participants were grouped according to their seniority (senior resident, N 2 years; nonsenior resident, b 2 years) and intubation experience (experi- enced, N 15 intubation experiences; nonexperienced, b 15 intubation experiences). Intubation time length and vocal cord visualization time length of the participants were recorded.
Our study included a total of 36 emergency residents, 22 male (61.1%) and 14 female (38.9%). Mean age of our participants was
31.03 years (min, 24; max, 47). Mean intubation time length by Macintosh laryngoscope was 20.17 +- 6.76 seconds (min, 8.8; max, 37.4) in MNM, 23.96 +- 8.85 (min, 9; max, 41.9) in MDM1, 23.41 +-
10.83 seconds (min, 8.2; max, 57.9) in MDM2. Mean intubation time length by video laryngoscope was 15.73 +- 8.24 seconds (min, 4.8; max, 46.3) in VNM, 19.18 +- 9.87 seconds (min, 8.9; max, 54.2) in VDM1, and 17.81 +- 10.66 seconds (min, 6.9; max, 65) in VDM2. Vocal cord visualization time length by Macintosh laryngoscope was 6.26 +-
3.44 seconds (min, 2.6; max, 15.1) in MNM, 11.85 +- 6.42 (min, 3.5;
max, 32.6) in MDM1, 8.95 +- 7.75 seconds (min, 2.9; max, 40.5) in MDM2. Vocal cord visualization time length by video laryngoscope was 3.58 +- 1.34 seconds (min, 1.5; max, 8.1) in VNM, 5.8 +- 3.65
seconds (min, 1.6; max, 14) in VDM1, and 4.21 +- 2.34 seconds (min,
1.2; max, 12.5) in VDM2.
Table 1
Repeated-measures analysis of variance results of intubation time length and vocal cord visualization time length of residents on 3 mannequins according to their seniority and experience
laryngoscopes as an alternative to Macintosh laryngoscopes in
Sum of |
df |
Mean of |
F |
P? |
Mannequins |
|
squares |
squares |
|||||
Intubation time length (Macintosh laryngoscope) |
||||||
Unexperienced |
18.804 |
2 |
9.402 |
0.229 |
.797 |
– |
Experienced |
484.785 |
2 |
242.392 |
4.761 |
.017 |
NM and DM1 |
Senior |
48.620 |
2 |
24.310 |
0.682 |
.514 |
– |
Nonsenior |
271.750 |
2 |
135.875 |
2.131 |
.139 |
– |
Intubation time (video laryngoscope) Unexperienced 314.316 2 157.158 3.947 .029 NM-DM1 |
||||||
Experienced |
46.372 |
2 |
23.186 |
0.479 |
.624 |
– |
Senior |
337.845 |
2 |
168.923 |
4.745 |
.015 |
NM-DM1 |
Nonsenior |
32.095 |
2 |
16.047 |
0.290 |
.750 |
– |
Vocal cord visualization time (Macintosh laryngoscope) |
||||||
Unexperienced |
189.907 |
2 |
94.954 |
2.741 |
.082 |
– |
Experienced |
339.242 |
2 |
169.621 |
9.159 |
.001 |
DM1-DM2 |
Senior |
376.232 |
2 |
188.116 |
5.040 |
.013 |
NM-DM1-DM2 |
Nonsenior |
164.255 |
2 |
82.128 |
6.374 |
.007 |
NM-DM1 |
Vocal cord visualization time (video laryngoscope) |
||||||
Unexperienced |
56.251 |
2 |
28.126 |
4.987 |
.013 |
NM-DM1 |
Experienced |
27.208 |
2 |
13.604 |
3.771 |
.035 |
NM-DM1 |
Senior |
49.084 |
2 |
24.542 |
4.520 |
.017 |
NM-DM1 |
Nonsenior |
37.000 |
2 |
18.500 |
5.284 |
.012 |
NM-DM1 |
difficult airway management using mannequins.
Our study was performed with 36 emergency residents aged between 24 and 27 years in our emergency department. Intubation experience and the number of years of residence of the participants were recorded. Before the study, residents underwent theoretical and practical education for 2 hours and were then asked to perform intubation on 3 different mannequins with the McGrath video laryngoscope and the Macintosh laryngoscope.
We used 3 different TrueCorp mannequins: (1) mannequin with normal cervical position (normal mannequin [NM]), (2) mannequin with cervical collar that restricted the motions of the operator as with trauma patients (difficult mannequin 1 [DM1]), (3) mannequin with enlarged epiglottis and tongue (difficult mannequin 2 [DM2]). Thirty
? Authors’ contribution: Conception and design, acquisition of data, or analysis and interpretation of data: Burcin Guvenc Yanik, Sadiye Yolcu, and Ismet Parlak; drafting the article or revising it critically for important intellectual content: Gizem Aydinok, Serhat Akay, and Vermi Degerli; final approval of the version to be published: Sadiye Yolcu, Mucahit Kapci, Onder Tomruk, Bulent Erdur, and Ismet Parlak.
?? All authors declare that they have no conflict of interest.
Bold indicates statistical significance in the table.
* Repeated measures anova analyse.
808 Correspondence / American Journal of Emergency Medicine 32 (2014) 797–810
Table 2
Intubation and visualization of vocal cord time length distribution according to seniority and experience of residents
Senior |
P |
Non-senior |
P |
Unexperienced |
P |
Experienced |
P |
||
Mean +- SD |
Mean +- SD |
Mean +- SD |
Mean +- SD |
||||||
Intubation time length |
MNM |
20.97 +- 6.02 |
.003 |
19.05 +- 7.75 |
.334 |
21.66 +- 6.61 |
.002 |
18.3 +- 6.67 |
.052 |
VNM |
15.56 +- 8.88 |
15.95 +- 7.54 |
15.16 +- 9 |
16.43 +- 7.4 |
|||||
MDM1 |
22.64 +- 8.54 |
.158 |
25.36 +- 9.28 |
.039 |
21.71 +- 8.31 |
.221 |
26.36 +- 9.07 |
.026 |
|
VDM1 |
19.86 +- 8.86 |
18.25 +- 11.4 |
19.52 +- 9.3 |
18.82 +- 10.75 |
|||||
MDM2 |
24.27 +- 12.0 |
.005 |
22.32 +- 9.44 |
.173 |
23.94 +- 11.87 |
.010 |
22.82 +- 9.89 |
.098 |
|
VDM2 |
16.97 +- 12.3 |
18.93 +- 8.22 |
17.73 +- 13.26 |
17.89 +- 6.84 |
|||||
Visualization of vocal |
MNM |
6.96 +- 4 |
.001 |
5.28 +- 2.23 |
.008 |
7.11 +- 4.17 |
.001 |
5.2 +- 1.87 |
.005 |
cord time length |
VNM |
3.66 +- 1.5 |
3.47 +- 1.13 |
3.44 +- 1.55 |
3.74 +- 1.06 |
||||
MDM1 |
12.76 +- 7.63 |
.001 |
10.63 +- 4.36 |
.021 |
11.13 +- 5.87 |
.002 |
12.68 +- 7.15 |
.009 |
|
VDM1 |
6.02 +- 3.81 |
5.46 +- 3.51 |
6.17 +- 3.97 |
5.35 +- 3.31 |
|||||
MDM2 |
10.59 +- 9.73 |
.005 |
6.88 +- 3.43 |
.001 |
9.62 +- 8.9 |
.006 |
8.21 +- 6.43 |
.001 |
|
4.59 +- 2.61 |
3.67 +- 1.86 |
4.56 +- 2.64 |
3.77 +- 1.91 |
Bold indicates statistical significance in the table.
Intubation time length (P N .05) and vocal cord visualization time length (P N .05) of senior and nonsenior residents were not significantly different. Similarly, intubation time length (P N .05) and vocal cord visualization time length (P N .05) of experienced and nonexperienced residents were not significantly different. Time length between visualization of vocal cord and completion of the intubation was not significantly different between experienced and nonexperienced resident groups (P b .05). Time length between visualization of vocal cord and completion of the intubation was not significantly different between the 3 mannequins (P N .05).
Thirty-two residents (88.8%) performed successful intubation with Macintosh laryngoscope, and 29 participants (80.5%) performed successful intubation with video laryngoscope on NM.
Twenty-five (69.4%) were successful with Macintosh laryngo- scope, and 32 (88.8%), with video laryngoscope on DM1. These ratios for DM2 were 21 (58.3%) and 30 (83.3%), respectively.
Repeated-measures analysis of variance results of intubation time length and vocal cord visualization time length of residents on 3 mannequins according to their seniority and experience are given in Table 1.
Intubation time of inexperienced residents was shorter with the video laryngoscope (P b .05) than with the Macintosh laryngoscope (P b .05) on NM and DM2. Intubation and vocal cord visualization time length distribution of participants according to their seniority and experience is given in Table 2.
Table 3
Success of intubation due to mannequins
Success of intubation
Unsuccessful Successful P
n % n %
Intubation success ratios were significantly different with the Macintosh laryngoscope on NM and DM1 (P b .05) (Table 3).
All 2 paired group results were significantly different for intubation difficulty ratios according to mannequins and laryngo- scopes (P b .05) (Table 4).
Mean intubation and vocal cord visualization time length was significantly shorter with video laryngoscopes using the same mannequins (P b .05) (Table 5).
Table 4
Difficulty level distribution of intubation due to mannequins
Difficulty level of intubation P
Easy |
Medium |
Difficult |
|||||||
n |
% |
n |
% |
n |
% |
||||
MNM |
10 |
27.8 |
21 |
58.3 |
5 |
13.9 |
.001 |
||
MDM1 |
5 |
13.9 |
– |
– |
31 |
86.1 |
|||
MNM |
10 |
27.8 |
21 |
58.3 |
5 |
13.9 |
.004 |
||
MDM2 |
6 |
16.7 |
14.0 |
38.9 |
16 |
44.4 |
|||
MDM1 |
5 |
13.9 |
– |
– |
31 |
86.1 |
.001 |
||
MDM2 |
6 |
16.7 |
14.0 |
38.9 |
16 |
44.4 |
|||
VNM |
34 |
94.4 |
2 |
5.6 |
– |
– |
.001 |
||
VDM1 |
19 |
52.8 |
10.0 |
27.8 |
7 |
19.4 |
|||
VNM |
34 |
94.4 |
2 |
5.6 |
– |
– |
.013 |
||
VDM2 |
26 |
72.2 |
8.0 |
22.2 |
2 |
5.6 |
|||
VDM1 |
19 |
52.8 |
10 |
27.8 |
7 |
19.4 |
.048 |
||
VDM2 |
26 |
72.2 |
8.0 |
22.2 |
2 |
5.6 |
|||
MNM |
10 |
27.8 |
21 |
58.3 |
5 |
13.9 |
.001 |
||
VNM |
34 |
94.4 |
2.0 |
5.6 |
– |
– |
|||
MDM1 |
5 |
13.9 |
– |
– |
31 |
86.1 |
.001 |
||
VDM1 |
19 |
52.8 |
10.0 |
27.8 |
7 |
19.4 |
|||
MDM2 |
6 |
16.7 |
14 |
38.9 |
16 |
44.4 |
.001 |
||
VDM2 |
26 |
72.2 |
8.0 |
22.2 |
2 |
5.6 |
MNM MDM1 |
4 16 |
11.1 44.4 |
32 20 |
88.9 55.6 |
.004 |
Table 5 |
||||
MNM |
4 |
11.1 |
32 |
88.9 |
.508 |
Intubation and visualization of vocal cord time length of residents due to mannequins |
||||
MDM2 MDM1 |
7 16 |
19.4 44.4 |
29 20 |
80.6 55.6 |
.022 |
Mean +- SD |
P? |
|||
MDM2 |
7 |
19.4 |
29 |
80.6 |
Intubation time length |
MNM |
20.17 +- 6.76 |
.002 |
||
VNM |
2 |
5.6 |
34 |
94.4 |
.219 |
VNM |
15.73 +- 8.24 |
|||
VDM1 |
6 |
16.7 |
30 |
83.3 |
MDM1 |
23.96 +- 8.85 |
.008 |
|||
VNM |
2 |
5.6 |
34 |
94.4 |
.625 |
VDM1 |
19.18 +- 9.87 |
|||
VDM2 |
4 |
11.1 |
32 |
88.9 |
MDM2 |
23.41 +- 10.83 |
.002 |
|||
VDM1 |
6 |
16.7 |
30 |
83.3 |
.625 |
VDM2 |
17.81 +- 10.66 |
|||
VDM2 |
4 |
11.1 |
32 |
88.9 |
Visualization of vocal cord |
MNM |
6.26 +- 3.44 |
.001 |
||
MNM |
4 |
11.1 |
32 |
88.9 |
.687 |
time length |
VNM |
3.58 +- 1.34 |
||
VNM |
2 |
5.6 |
34 |
94.4 |
MDM1 |
11.85 +- 6.42 |
.001 |
|||
MDM1 |
16 |
44.4 |
20 |
55.6 |
.006 |
VDM1 |
5.8 +- 3.65 |
|||
VDM1 |
6 |
16.7 |
30 |
83.3 |
MDM2 |
8.95 +- 7.75 |
.001 |
|||
MDM2 |
7 |
19.4 |
29 |
80.6 |
.453 |
VDM2 |
4.21 +- 2.34 |
|||
VDM2 |
4 |
11.1 |
32 |
88.9 |
Bold indicates statistical significance in the table. |
Bold indicates statistical significance in the table. ? Wilcoxon signed ranks analyse.
Correspondence / American Journal of Emergency Medicine 32 (2014) 797–810 809
In our basic medicine and emergency residency education system, there is no simulation and no mannequin education for intubation. As a result, we determined longer intubation time lengths when compared with other studies.
In conclusion, intubation and vocal cord visualization times were shorter for the McGrath video laryngoscope, and it was found to be more successful for Difficult airways than the Macintosh laryngoscope. Thus, we concluded that the video laryngoscope should be used for difficult airway management for better results.
Simulation and mannequin supported intubation and difficult airway management education should be added to the education programme of medical students and emergency residents.
Burcin Guvenc Yanik
Department of Emergency Medicine Bozyaka Research and Education Hospital Izmir Turkey
Sadiye Yolcu Department of Emergency Medicine Bozok University Yozgat Turkey
E-mail address: [email protected]
Gizem Aydinok Serhat Akay Vermi Degerli
Department of Emergency Medicine Bozyaka Research and Education Hospital Izmir Turkey
Onder Tomruk Department of Emergency Medicine Suleyman Demirel University Isparta Turkey
Bulent Erdur Department of Emergency Medicine Pamukkale University Denizli Turkey
Mucahit Kapci Department of Emergency Medicine Adnan Menderes University
Aydin Turkey
Ismet Parlak
Department of Emergency Medicine Bozyaka Research and Education Hospital Izmir Turkey
http://dx.doi.org/10.1016/j.ajem.2014.02.037
References
- Asai T. Videolaryngoscopes: do they truly have roles in difficult airways? Anesthesi- ology 2012;116:515-7.
- Aziz MF, Healy D, Kheterpal S, et al. Routine clinical practice effectiveness of the Glidescope in difficult airway management: an analysis of 2,004 Glidescope intubations, complications, and failures from two institutions. Anesthesiology 2011;114:34-41.
- Aziz MF, Dillman D, Fu R, et al. Comparative effectiveness of the C-MAC video laryngoscope versus direct laryngoscopy in the setting of the predicted difficult airway. Anesthesiology 2012;116:629-36.
The author responds
To the Editor,
We are grateful for the comments of Vezzali et al, [1] and we agree with them that a combined method of B-mode and contrast enhanced ultrasonography would help identify the correct
position of the Central venous line (CVL) tip. In our study, we checked in B-mode the Seldinger during canulation and before dilatation of the vessel (to avoid complication), and we believe it is also important to check omo- and controlateral neck veins after CVL insertion to identify intravascular malpositioning. Regarding ultrasound evaluation of the tip position of the CVL in the intrathoracic vessels using B-mode, we can see the tip in the neck veins and only few centimeters before the entrance of superior vena cava (SVC) in right atrium (this means that the tip might be anywhere distal the brachiocephalic vein); in our study, CEUS could not differentiate the malpositioning of CVL in brachiocefalic vein as the delay of appearance compared with correct positioning in SVC is not detectable with visual extimation time of bubble appearance in right atrium (RA).
B-mode could be useful to visualize the tip in the RA cavity.
A combination of B-mode and CEUS is feasible and not really time consuming, and we believe it must be used to check intravascular malpositioning in the neck veins and to confirm correct tip positioning with the limitation that we will not be able to visualize the tip distally to the brachiocephalic vein until the entrance of SVC into the atrial vein.
Francesca Cortellaro, MD Unita Operativa di Pronto Soccorso e Medicina D‘urgenza, Dipartimento di Emergenza e Urgenza, Ospedale Maggiore Niguarda, Milano, Italy
E-mail address: [email protected] http://dx.doi.org/10.1016/j.ajem.2014.02.001
Reference
Vezzani A, Brusasco C, Corradi F. Contrast-enhanced ultrasound to determine correct central venous catheter position. Am J Emerg Med 2014 Feb 4. http://dx.doi.org/ 10.1016/j.ajem.2014.01.033. pii: S0735-6757(14)00063-1. [Epub ahead of print].
Contrast-enhanced ultrasound to determine correct central venous
catheter position?
To the Editor,
We read with great interest the paper recently published by Cortellaro et al titled “Contrast enhanced ultrasound versus chest x-ray to determine correct central venous catheter position” [1]. We agree with the authors’ conclusion that contrast-enhanced ultrasound (CEUS) by itself cannot substitute chest x-ray in evaluating the catheter tip position after Central venous catheter placement. Nevertheless, we would like to make some methodological com- ments. In a recent study [2] combining B-mode ultrasound with CEUS, we obtained an estimate of correct catheter position in atrio-caval junction that was much more accurate than in the study of Cortellaro et al (sensitivity 96% vs 33%, specificity 93% vs 98%). We used an epigastric bicaval acoustic window, by which right atrium and both cava veins can by visualized, thus directly showing the catheter tip and CEUS exit point. By contrast Cortellaro et al used in 17% of cases the apical acoustic windows, which increased feasibility up to 100% compared with 89% in our study but did not allow the visualization of cava veins. We think direct visualization of the catheter tip or CEUS exit point is important because bubbles arrive in the right atrium even in cases of intravascular malposition, although with a short time delay from CEUS infusion, except when the catheter tip is in the inferior vena cava. In this case, however, malposition can be directly revealed by B-mode ultrasound with the epigastric bicaval acoustic window. For these reasons and the availability of B-mode ultrasound,