Page 94 - JSOM Summer 2018

Laryngeal Mask Ethics
The Ambu AuraOnce (Figure 2) features a special 70° curve The study was approved by the Regional Ethical Review
that is supposed to replicate natural human anatomy. It does Board in Uppsala. Each patient was asked before premedica-
not contain natural rubber latex. The LMA has a color-coded tion if they would like to be part of the study and was given
pouch with directions for use. written and oral information by an anesthesiologist of the
aim, method, and complications of the study, after which they
™
FIGURE 2 Ambu AuraOnce Disposable Laryngeal Mask. signed a written informed consent. They were informed that
®
they could withdraw from the study at any time without ad-
verse effect to their care and that their personal data were pro-
tected and anonymity was guaranteed.
Analysis
The success rates within the interventions and between the air-
way adjuncts were compared using the χ test. For compari-
2
son between insertion times, Student t test was used. P < .05,
two tailed, was considered statistically significant. Data were
analyzed with SPSS, version 18.0, for Windows (IBM, https://
www.ibm.com). Descriptive statistics are presented as num-
bers, mean, standard deviation, range, and percentage.

Results
Twenty-one patients were eligible for the study and asked to
participate; two declined. The demographics of the 19 patients
are listed in Table 1. Eight medics performed the interventions.
When performing their first insertion with the LTS-D, four of
Intervention the eight required one attempt, two required two attempts,
The anesthesia clinical team administered the anesthesia and and two medics were unable to insert the LTS-D independent
when mask ventilation and oxygenation were verified (i.e., ox- of number of attempts (ie, more than twice). The accumulated
ygen saturation, ETco , rise and fall of the chest), the medic success rate for all first attempts with the LTS-D was 14 of 19
2
was given the responsibility of inserting the airway adjuncts. interventions (73.7%); for second attempts, 16 of 19 (84.2%)
They were allowed to freely manipulate the airway and the (Table 2).
airway adjunct to optimize intubation with the adjuncts. They
were given no verbal or hands-on assistance with the insertion TABLE 1 Patient Characteristics
and were responsible for inserting the adjunct and manually Age, mean (SD), years 51.9 (17.9)
verifying adequate ventilation. Sex, female/male 16/3
ASA I/II 9/9
The clinical anesthesia team was responsible for overseeing
the airway intervention, attaching the tube to a ventilator, and Mallampati I/II/III 12/4/1
verifying ventilation. After the anesthesiologist confirmed ven- Length in study, mean (SD) 170 (7.0)
tilation without leakage and the patient was adequately oxy- Weight, mean (SD), kg 75 (15.5)
genated, the first adjunct was removed and the second adjunct
was used. The mean (range) insertion times with the LTS-D were time to
cuff, 37.1 (19–74) seconds; time to ventilation; 46.1 (25–88)
Each medic was tested on at least two and not more than three seconds; time to verified ventilation, 58.7 (33–132) seconds;
patients, with two attempts for each adjunct. One attempt was and time to verified ventilation without leakage, 60.1 (33–154)
considered terminated if the adjunct was extracted beyond the seconds (Table 3). There were no significant improvements in
incisors. When the patient was adequately ventilated or the insertion time regarding the LTS-D (Table 4).
medic had performed a maximum of two attempts, the trial
was completed. For both adjuncts, the timing was started by The first insertion with the LMA had a 100% (8/8) success
the researcher when the adjunct passed the incisors. Time pa- rate and the second insertion had a success rate of 87.5% (7/8;
rameters measured in seconds were time to correct placement Table 2). The mean (range) insertion times with the LMA were
(i.e., LMA in the hypopharynx with distinct resistance or the as follows: time to correct placement, 17.5 (5–55) seconds,
adjunct could advance no further), time to cuff (i.e., LTS-D in time to ventilation, 28.3 (7–68) seconds; time to verified venti-
the hypopharynx with distinct resistance or the adjunct could lation, 44.3 (16–120) seconds; and time to verified ventilation
advance no further and tube cuffed), time to ventilation (i.e., without leakage, 48.3 (16–120) seconds (Table 3). There was
chest rise and fall, passage of air to the lungs), time to verified a significant decrease in the time to verified ventilation and
ventilation (i.e., ETco , auscultation of ventricle and the chest verified ventilation with no leakage with the LMA (p = .043
2
bilaterally) and time to verified ventilation without leakage and p = .029, respectively) with respect to first and second in-
(i.e., free passage of air without obstruction and ventilation sertions (Table 4). In all, there were three LTS-D (15.8%) and
verified with ETco , auscultation of ventricle and the chest one LMA (5.3%) insertion attempts that failed. The LTS-D
2
bilaterally). After each airway intervention, the medic and re- sizes used were two (10.5%) size 3 and 16 (84.2%) size four;
search team discussed possible complications and errors made, no size was reported for one intervention. The LMA sizes used
which were recorded in the protocol. were one (5.3%) size 3 and 18 (94.7%) size 4.

92 | JSOM Volume 18, Edition 2/Summer 2018