2. MATERIAL AND METHODS:
After obtaining ethics committee approval (Ankara Numune Education and
Research Hospital Ethics Committee, numbered E-15-666 and dated
20/01/2016) and written informed consent from patients and
practitioners, this single-center, prospective, randomized,
observer-blinded cross-over study was conducted between January 2016 and
March 2016.
24 anesthesiology residents and 12 specialist anesthesiologists
participated in the study in the general surgery operation theatre. Each
of the practitioners ventilated 4 patients with non-dominant hand. Each
of the patients ventilated with IOM (NuMASK®) and CFM (AMS) at settled
pressure (20 cmH20) and frequency (12/min) with Dräger Perseus®
anesthesia device for one minute per mask. Application order of the
masks was determined by the closed envelope method. Mask ventilation
efficiency of 144 ASA I-II-III patients aged 18-65 years was evaluated.
The exclusion criteria of our study were as follows; initial SPO2 value
<95%, severe pulmonary or cardiac diseases, tumor or goiter
restricting the airway, tooth mobility and SPO2<90% during
mask ventilation for any reason
The State-Trait Anxiety Inventory TX-2 (Trait Anxiety Scale Scoring)
levels, age, gender, and years of anesthesia experience of the
participants were recorded.
In preoperative examination patient’s name, protocol number, age,
gender, comorbidities, ASA score, Mallampati score, weight, height, Body
mass index (BMI), neck circumference(NC), thyromental distance (TMD),
sternomental distance (SMD), hyo-mental distance (HMD), interincisor
distance (IID), whether he had teeth, whether he had a beard, and
whether there was any limitation in neck movements were recorded.
The risk of Obstructive Sleep Apnea was determined with the STOP-Bang
Scoring Model 19. Patients who answered yes to 3 or
more questions were registered as high risk of OSAS (STOP_BANG≥3), and
patients who answered yes to less than 3 questions
(STOP_BANG<3) were recorded as low risk of OSAS.
Anesthesia was induced with 0.05 mg.kg-1 midazolam,
1.0 mcg.kg-1 fentanyl, 2 mg.kg-1propofol and 0.5mg.kg-1 rocuronium after eight hours
of fasting. Intraoperative noninvasive blood pressure,
electrocardiography, and SpO2 were performed. The
patient was placed comfortably in the supine and sniffing position. The
practitioner firstly ventilated the patient for 1 minute with the first
randomly predetermined mask. Before the second mask, mask ventilation
was transferred to an assistant and the practitioner rested for 1
minute. Then the practitioner ventilated for another one minute with the
second mask. During ventilation periods a blinded observer recorded mean
TV, mean end-tidal carbon dioxide (etCO2) levels, SpO2and LV for both masks. The effectiveness of ventilation of the masks
were also assessed by another observer with the Han Mask Ventilation
scale20. For Han scale=I (easy ventilation)
ventilation was considered successful. For Han scale>I
(II=Needs oral airway, III= requiring two care providers, IV= unable to
mask ventilate) ventilation was considered successful.
After the 4th patient, practitioners completed the State-Trait Anxiety
Inventory TX-1 (State-Trait Anxiety Scale Scoring) form and the NASA-TLX
(The National Aeronautics and Space Administration-Task Load
Index)21 forms to measure their anxiety for IOM and
CFM. .