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. .