The effect of cricoid pressure on the Clarus Video System (Trachway)-assisted endotracheal intubation in simulated rapid sequence induction intubation: A randomized controlled trial
This study was approved by Chang Gung Medical Foundation Institutional Review Board and a written informed consent was obtained from each patient. The patients participating in this clinical trial were older than 20 years of age and scheduled for elective surgeries under general anesthesia. Patients were excluded if they had BMI (Body Mass Index) > 35 kg/m2, interincisor distance < 3 cm, poor dentition, upper airway tumor, limited neck mobility, pregnancy or history of difficult tracheal intubation. One hundred fifty patients were enrolled and, based on computer-generated random numbers, were assigned to one of three groups: the CVS as a video stylet (CVS-V) group, the CVS as a lightwand (CVS-L) group and direct laryngoscope (DL) group. In this trial, a successful intubation was defined as the intubation was completed within 30 seconds. Intubation time was counted from inserting the device into the patient’s mouth to viewing the endotracheal tube into the trachea. The intubation time for patients who required more than one attempt was the sum of the times of all the intubation attempts. The following data were also collected: (1) airway parameters (Mallampati classification, thyromental distance, interincisor distance and neck circumference); (2) hemodynamic stress response; (3) sore throat and mucosa injury (documented by a blinded observer on the next day).
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After the intravenous line was checked and monitors, including electrocardiography, pulse oximetry and noninvasive blood pressure measurement, were correctively positioned, the patients breathed 100% oxygen for 3 minutes. Anesthesia was induced with fentanyl (2 µg/kg), lidocaine (20 mg), propofol (2 mg/kg) and rocuronium (1.2 mg/kg) intravenously. Sixty seconds following the injection of rocuronium, each patient was intubated with the assigned device and an endotracheal tube of proper size while 30-40N pressure was being applied on the cricoid cartilage by an assistant standing on a weighing scale. Following checking the position and tapping of the tube, sevoflurane 4% in 50% oxygen with a fresh gas flow 4 L/min was initially provided from a circle system and then the concentration of the inhalation anesthetic was adjusted in accordance with the patient’s need.