Brief Report
The Pentax-AWS Video-Laryngoscope: The First
Experience in One Hundred Patients
Takashi Asai, MD, PhD*
Yoshiro Enomoto, MD†
Keiko Shimizu, MD†
Koh Shingu, MD*
We studied the efficacy of the Pentax-AWS (Tokyo, Japan), a new portable,
battery-operated video-laryngoscope, in 100 patients. It was possible to insert the
blade of the Pentax-AWS and to see a full view of the glottis on the first attempt in
99 of 100 patients. In the remaining patient, insertion of the Pentax-AWS was
abandoned because of a risk of damaging teeth that were already loose. Tracheal
intubation was successful in 98 patients. The median time taken for tracheal
intubation was 35 s (range, 5–120 s).
(Anesth Analg 2008;106:257–9)
Yasuhisa Okuda, MD†
T
he Pentax-AWS (Pentax, Tokyo, Japan) (Fig. 1) is a
new video-laryngoscope consisting of a disposable
transparent blade (PBLADE®), a 12-cm cable with a
charge-coupled device (CCD) camera, and a 2.4-inch
liquid crystal device monitor display (Figs. 1 and 2).1–3
The main unit (Fig. 2) is waterproof, facilitating cleaning with water or a disinfectant, such as ethanol. The
device is light (290 g without batteries). The image is
displayed on a full-color screen. A tracheal tube can be
attached to the right side of the blade (Fig. 1). There is
a green target symbol on the monitor display, which
indicates the direction of the tracheal tube tip. The
PBLADE blade has a port through which a suction
catheter can be passed. The distal aperture of the
suction port is near the CCD camera, so that the tip of
the suction catheter will come into view.
The Pentax-AWS has been commercially available
in Japan since July 2006, and has been described in a
limited number of patients.1–3 The purpose of this
study was to evaluate the efficacy of the Pentax-AWS
in 100 anesthetized patients.
METHODS
We obtained several Pentax-AWS video-laryngoscopes
soon after the devices were licensed for clinical use.
From the *Department of Anesthesiology, Kansai Medical University, Moriguchi City, Osaka, Japan; †Department of Anesthesiology, Koshigaya Hospital, Dokkyo University School of Medicine,
Saitama, Japan.
Accepted for publication August 13, 2007.
Address for correspondence and reprint requests to Takashi
Asai, MD, PhD, Department of Anesthesiology, Kansai Medical
University, 10-15 Fumizono-cho, Moriguchi City, Osaka 570-8507,
Japan. Address e-mail to [email protected].
The Pentax-AWS video-laryngoscope used by Dr. Asai was on a
short-term loan from the manufacturer. The model used by the
other investigators was purchased by their departments. No direct
financial support was obtained.
Copyright © 2007 International Anesthesia Research Society
DOI: 10.1213/01.ane.0000287647.46165.bc
Vol. 106, No. 1, January 2008
We informed patients before anesthesia as to the use
of this new device, and told them they could request
the use of a conventional laryngoscope if they preferred. Because of ethical concerns, we did not use the
device in patients whose airways appeared difficult to
manage. In addition, we did not use the device in
patients with an ASA physical status of 4 or more,
patients with any pathology of the neck or upper
respiratory tract, or patients at risk of pulmonary
aspiration.
With the approval of our local research ethics
committee, we retrospectively collected data from 100
patients who underwent general anesthesia during
elective surgery in whom tracheal intubation was
indicated. No patients reported previously2,3 were
included in this group.
An 8.0-mm ID polyvinylchloride tracheal tube
(Portex, Kent, UK) (for males) or a 7.0-mm ID tube
(for females) was attached to the groove of the
blade, and the tip of the tracheal tube was positioned just beyond the CCD camera (Fig. 3). After
induction of anesthesia and neuromuscular blockade, one of three senior anesthesiologists (trained
with manikins beforehand) inserted the PentaxAWS, and advanced the tip of the blade toward the
glottic side of the epiglottis, as with the Miller
laryngoscope. The position of the device was adjusted so that the glottis was in the center of the
green target symbol (Fig. 3), and tracheal intubation
was attempted. Time to intubate the trachea, starting from picking up the Pentax-AWS to removal of
the scope after successful tracheal intubation was
measured. Any problems associated with its use
were recorded.
RESULTS
Of 100 patients, 53 patients were males and 47 were
females (Table 1). It was possible to insert the blade of
the Pentax-AWS and to see a full view of the glottis on
257
Figure 1. Pentax-AWS videolaryngoscope (Pentax, Japan). A
tracheal tube is attached to the groove of the PBLADE blade.
The tip of the tube should be positioned just beyond the
CCD camera.
Figure 3. Tracheal intubation using the Airway Scope. The
position of the device is adjusted so that the glottis is located
in the target symbol, and the tube is advanced into the
trachea.
Table 1. Patients’ Characteristics (Mean (SD) 关Range兴)
Age
Height (cm)
Weight (kg)
Body mass index (kg 䡠 m⫺2)
Mallampati score (1, 2)
Interincisor distance (cm)
Thyromental distance (cm)
54 (14.5) 关21–80兴
160 (9.2) 关138–183兴
60 (11.9) 关30–90兴
23.5 (3.5) 关15.3–33.9兴
93, 7
5.4 (1.0) 关4–11 兴
7.9 (1.2) 关5–11兴
from the blade during an attempt at intubation (with a
successful intubation). There was no damage to teeth,
bleeding from the oropharynx, or hypoxia.
DISCUSSION
Figure 2. Main unit of the Pentax-AWS.
the first attempt in 99 of 100 patients. In the remaining
patient, insertion of the Pentax-AWS was abandoned
because the anesthesiologist judged that it might damage teeth that were already loose. Tracheal intubation
was successful in 98 patients (in 96 patients on the first
attempt and in 2 patients on the second attempt). In the
remaining patient, intubation failed because the tube
kept impacting on the arytenoids. The median time for
tracheal intubation was 35 s (range, 5–120 s). The only
equipment malfunction was tracheal tube dislodgement
258
Brief Report
It was generally easy to insert the Pentax-AWS, to
obtain a full view of the glottis, and to intubate the
trachea, without major complications. Previous videolaryngoscopes have suffered from difficulty in advancing the tracheal tube into the trachea because the
glottis was not under direct view, requiring frequent
need to adjust the shape of the tracheal tube with a
stylet.4,5 In contrast, with the Pentax-AWS, a tracheal
tube can be attached to the side of the blade, and the
tip of the tube is already shown on the monitor
display. In our patients, once the glottis was positioned in the target symbol, it was easy to advance the
tube into the trachea in 98 of 99 patients.
ANESTHESIA & ANALGESIA
The Pentax-AWS may be difficult to use in patients
with limited mouth opening because the maximum
width of the blade is approximately 2.5 cm. Another
possible disadvantage is that there is a theoretical risk of
blurred images by fogging. Nevertheless, in our patients,
this was rare. The manufacturer suggests that fogging is
infrequent, because the CCD camera will not be exposed
to humid air in the oropharynx, and because the blade is
slightly warmed by the camera light. Lastly, the singleuse blade costs 2500 yen or approximately 20 dollars,
and thus its routine use may be restricted. There have
been several reports of successful use of videolaryngoscopes in patients with difficult airways.5–7 If the
Pentax-AWS is effective in patients with difficult airways, this expenditure may be justifiable.
Vol. 106, No. 1, January 2008
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© 2008 International Anesthesia Research Society
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