Need Tracheal Intubation Clinical Trial
Official title:
Does King Vision® Videolaryngoscope Reduce Cervical Spine Motion During Endotracheal Intubation? A Cross-over Study.
Extensive cervical spines movement during endotracheal intubation can result in serious
neurological injury, especially in the patients with unrecognized cervical spines
injury.[1-2] Moreover, direct laryngoscopy may be difficult if spine movement is limited
because of arthritis, disc disease or a small gap between the occiput and the spinous
process of the atlas.[3-4]
Video laryngoscopes allow for intubation without alignment of the oral, pharyngeal, and
tracheal axes which minimize the cervical movements, especially in the patients with
restricted cervical movements. [5,6] Compared with the Macintosh laryngoscope, the use of
AirWay Scope decreases median upper cervical-spine movement during intubation under in-line
stabilization in patients with normal cervical-spine. [6] Unfortunately, the use video
laryngoscopes are associated with longer times to tracheal intubation compared with the
traditional techniques which may be attributed to the variable learning curves of the
practitioners. [7-9]
The King Vision video laryngoscope® (King Systems Company, a division of Consort Medical,
Indianapolis, Indiana, USA) is an anatomically shaped, rigid laryngoscope that uses
fiberoptic technology to view the larynx with micro camera offers a 160 degree of view
potentially eliminating the need for neck flexion and head extension. [10]
To the best of the authors' knowledge, there is no study has evaluated the King vision
laryngoscope regarding the neck movement during routine tracheal intubation under general
anesthesia.
Hypothesis:
The investigators hypothesize that the use of King Vision video laryngoscope may reduce the
cervical spines movements during endotracheal intubation compared with the Macintosh
laryngoscope.
Aim of the study:
The present clinical trial aims to compare the effects of the Macintosh and King Vision
laryngoscopes, on cervical spines movement, time to intubation, laryngoscopic view, ease of
intubation, number of intubation attempts, and number of optimization maneuvers during
tracheal intubation, in the patients undergoing minor elective surgery under
propofol-remifentanil-rocuronium anesthesia.
Methods:
Thirty two ASA I-II patients who need tracheal intubation will be included in this
randomized cross-over controlled blind comparative study at the author's center after
obtaining approval of the local Ethical Committee and an informed written consent from all
participants.
The Mallampati airway score, thyromental and sternomental distances, neck extension, and the
degree of mouth opening will be evaluated preoperatively as factors predicting difficult
intubation.
Sample size calculation:
A priori power analysis of the previous published data [9] showed that the investigators
will need to study 14 pairs to detect a 10% difference in the cervical spine extension
(occiput-C5) values (25.9 degrees) with a SD of 2.8 degrees, after intubation with of
Macintosh laryngoscope, a type-I error of 0.05 and a power of 90%. The investigators will
add 10% more patients for a final sample size of 32 patients to account for patients
dropping out during the study.
Anesthesia:
Patients will be placed on the operating room table with a rigid board from the shoulders to
the occiput with the patient's head rested on a pillow in a position judged by the patient
to be neutral. After verification that the patient will be properly centered, the
fluoroscopy unit and operating room table will remain fixed for the rest of the study.
Patients' monitoring includes pulse oximetry, noninvasive blood pressure
electrocardiography, state and response Entropy (SE and RE) and train of four
(TOF)stimulation of the ulnar nerve.
Anesthetic technique will be standardized in all studied. After breathing 100% oxygen for 3
min through a facemask in a neutral position, anesthesia will be induced with fentanyl
2-3µg/kg/min and propofol 2-3 mg/kg to achieve a SE < 50 and the difference between RE and
SE less than 10. Rocuronium 0.6 mg.kg will be administered for complete relaxation on the
TOF (TOF-GE, Datex-Ohmeda Division, Instrumentarium Corporation, Helsinki, Finland).
Anesthesia will be maintained using sevoflurane end-tidal concentrations of 2.5-3.5% in
oxygen via a bag-mask for 3 min before endotracheal intubation.
Standard precautions against radiation exposure will be taken, movement of the cervical
spines during endotracheal intubation will be studied and recorded with portable X-ray
machine. Laryngoscopy will be performed twice, once with the King Vision and once with the
Macintosh laryngoscope in random order. For the first device, the patient's mouth will be
opened and the tip of the tracheal tube will be introduced into the glottis. The second
device will be studied in an identical manner, and intubation will be completed with the
second device. The intubators who will participate in the study will receive a standard
manikin based training which will be followed with 50 successful endotracheal intubations in
the clinical practice with the use of Macintosh and King Vision® laryngoscopes.
The studied data during intubation will be collected by an independent investigator. The
intubator will attempt to minimize neck movement during both techniques through the
acceptance of the first view [8] that will offer a reasonable opportunity to adequately
position the tracheal tube at the glottis opening.
Three lateral radiographs will be taken with a portable X-ray system provides fixed images
from which hard copies are generated. Patient will be served as their own control with
reference to the first image, which will be obtained after induction of anesthesia before
laryngoscopy and intubation, with the patient in neutral position. A further two images, one
with the Macintosh and one with King Vision laryngoscopes. These images will be taken at the
time of laryngeal exposure, with the tip of the endotracheal tube passing between the vocal
cords.
On each image, lines will be drawn to mark the relative position of the occiput, atlas (C1),
axis (C2) and the fifth cervical vertebra (C5). The angle between each of these lines will
be measured to determine the degree of angulation of C1, C2 and C5 relative to the occiput
and each other. [9] The radiographs will be reviewed by a radiology consultant who will be
blinded to the order of intubation technique and unfamiliar with the laryngoscopes being
used.
Statistical Analysis
Data will be tested for normality using the Kolmogorov-Smirnov test. Fisher exact test will
be used for categorical data. Repeated two-way ANOVA and paired t-test will be used to study
the changes in the primary and secondary endpoints during each intervention. The Wilcoxon 2
rank sum test will be used for the non-parametric values. The investigators will avoid the
carryover effect (persistence of the effect of the first intervention on the operative
conditions into the second period) through the comparison of the effects of period (time
effect) and the order of treatment using independent t-tests. Data will be expressed as mean
± SD, number (%), or median [range]. A value of P < 0.05 will be considered to be
statistically significant.
;
Allocation: Randomized, Endpoint Classification: Safety Study, Intervention Model: Crossover Assignment, Masking: Single Blind (Investigator), Primary Purpose: Prevention