Protocol
This study was approved by the Local Ethics Committee (Protocol no: 2018/165) and registered at www.ClinicalTrials.gov (# NCT03903679). We conducted a prospective, randomized, single-blind, and controlled clinical study with 80 adult patients undergoing septoplasty surgery at a university hospital. This manuscript adheres to the Consolidated Standards of Reporting Trials (CONSORT) statement[10].
Study Design
For the purposes of randomization, it was ensured that the patients were randomly assigned to the study groups, and selection bias was avoided. For this purpose, the MedCalc for Windows, Version–16 statistical software (medcalc.com.tr.) was used. A total of 80 patients were randomized into two groups: LMA-S (n = 40) and ETT (n = 40).
Study Participants
The patients agreed to participate in the study voluntarily. After they were informed about the potential risks and predicted results of the study, they completed the written informed consent forms. The study was conducted with patients, aged 18–65, who were scheduled for elective nasal septum surgery (American Society of Anesthesiologists (ASA) I-II).
In the preoperative anesthesia evaluation, patients with scores higher than ASA II and patients who had severe respiratory, hepatic, or renal dysfunction; neurology and/or psychiatry disorders; an allergy to anesthesia drugs, a body mass index (BMI) over 30; a difficult airway history (cervical spine pathology, modified Mallampati class 4, or thyromental distance < 65 mm); or a history of gastroesophageal reflux or hiatal hernia were excluded from the study.
Preoperative Procedures
The general anesthesia was standardized for all patients. Noninvasive blood pressure (NIBP), pulse oximetry (SpO2), electrocardiogram (ECG), and standard monitoring were applied to the patients who were admitted to the surgery room. Following this stage, preoperative oxygenation was performed with 100% oxygen for three minutes (min).
General Anesthesia
Anesthesia induction was carried out with propofol 2.5 mg.kg–1 intravenously (IV) + remifentanil 3 μg.kg–1 IV in both groups, and no myorelaxants were used. After the patients lost consciousness and following adequate mandibular relaxation, the LMA-S was inserted using a single‐hand rotation technique with the cuff lubricated. The back side of the cuff was lubricated with a water‐soluble gel (K‐Y®, Johnson & Johnson™, Les Moulineaux, France), and the cuff of the mask was fully deflated before insertion. Intubation and the previous steps were carried out by the same anesthesiologist, who had at least five years of experience with an over 90% success rate in orotracheal intubation and laryngeal mask placement. Cases in which the endotracheal tube or the LMA-S was not inserted correctly were excluded from the study.
The LMA-S size was chosen according to body weight in accordance with the manufacturer guidelines (< 50 kg, size 3; 50–70 kg, size 4; 70–100 kg, size 5) and previous studies [11,12]. The ETT size was 8 in male patients and 7 in female patients (cuffed endotracheal tube). The LMA-S intracuff pressure of 60 cm H2O was adjusted to the ETT cuff pressure of 20 cm H2O/1 manometer (Portex Cufator Endotracheal Tube Inflator and Manometer, Portex® Limited, Hythe, Kent, United Kingdom) [13]. The accuracy of the airway devices used in both groups was confirmed by the lack of sound from leaking air from the mouth, the expansion of the chest during ventilation, five consecutive capnography curves on the monitor, and osculation. With the LMA-S, a nasogastric tube was inserted into the LMA drainage tube. Air leakage to the stomach was controlled by checking for bubbles (foam) at the proximal end of the nasogastric tube [14].
Anesthesia was maintained in all patients with sevoflurane 50% oxygen and air, and the sevoflurane was titrated to maintain bispectrality index (BIS) values between 40 and 60 during surgery. The depth of anesthesia was monitored using the BIS (VISTA Monitoring System, Massachusetts, United States of America). BIS sensors were placed in the right and left frontal areas under the hairline and covered with tape to prevent exposure to light. In addition, 0.1–0.3 µg/kg/min IV remifentanil infusion was used.
Mechanical ventilation was used in both groups in the volume-controlled ventilator mode (Dräger Primus ventilator, Dräger AG, Lübeck, Germany). The tidal volume was adjusted as 8 mL/kg and the respiratory rate was EtCO2 of 35–45 mm Hg intraoperatively.
Outcome Measures
The primary purpose of the present study was to evaluate tracheal blood leakage in patients, who underwent septoplasty and whose airway patency was maintained by the LMA-S or the ETT, using a fiberoptic bronchoscope. At the end of the surgeries, a 3.5 mm fiberscope (Karl Storz GmbH & Co. KG, Tuttlingen, Germany) was used to examine blood leakage through both airway devices (glottis/trachea, distal trachea). In the patients for whom an ETT was used, the posterior oropharynx was aspirated carefully at the end of the surgeries; after extubation, the presence of blood around the distal area of the ETT cuff was examined. To evaluate the presence of blood (glottis/trachea, distal trachea), a four-point scale was used (1 = absent, 2 = mild, 3 = moderate, 4 = severe) [9].
The secondary purpose of the study was to evaluate OLP; hemodynamic response, including HR and MAP; adverse events, including sore throat, nausea, and vomiting; dysphagia; and dysphonia. OLPs were measured for the LMA-S and the ETT when the head was in a neutral position. The O2 flow was set to 3 L/min in the flowmeter, and the expiratory valve was closed. To prevent bias, one researcher covered the airway device so that the airway device type was not visible; then, another researcher checked the peak pressure value as soon as the first researcher heard an oropharyngeal leak sound, confirming that the pressure remained constant (manometer stability test) [15]. This value was recorded as the OLP. To avoid exposing the lungs to barotrauma, when the peak inspiratory pressure reached 40 cm H2O, the expiratory valve was opened, and the test was ended. MAP and HR were measured immediately before anesthesia induction and at the 5th, 15th, 30th min of perioperatively and 5th min after the extubation and airway placement were confirmed.
In the 24-hour postoperative period, sore throat, nausea, vomiting, dysphagia, and dysphonia were recorded at the 2nd, 6th, 12th, and 24th hours. Sore throatwas defined as continuous pain felt independently from swallowing, evaluated using a numeric rating scale (NRS) between 0–10. According to the NRS, the sore throat score was evaluated as “0–1 none; 2–4 mild; 5–7 moderate; and 8–10 severe” [16]. A 4-point scale was used to determine the severity of the nausea and vomiting (0 = no nausea, 1 = mild-moderate nausea, 2 = less than two vomits an hour, 3 = more than two vomits an hour). Dysphonia was defined as difficulty in speaking because of difficult speech or pain. Dysphagia was defined as difficulty in swallowing or painful swallowing17.
Postoperative Management
The patients who opened their eyes with stimuli and had regular spontaneous breathing, a respiratory rate of 12–20/minute, and an oxygen saturation larger than 95% were extubated and taken to the recovery room. The patients were transferred to the Otorhinolaryngology ward when they achieved a modified Aldrete’s score of nine or greater (on a 0–12 scale), indicating recovery sufficient for the patient to be transferred from Postoperative Care Unit (PACU) to the ward18. All patients received a standard postoperative analgesic regime of paracetamol (1g) and tramadol (1–2 mg/kg) IV.
Sample Size
A type I error (alpha) 0.05, strength of the test (1-beta) 0.9, effect size 0.71 for the amount of blood in the primary output variable airway (glottis/trachea), and the alternative hypothesis (H1) were employed as the variables used to calculate the minimum sample size. Subsequently, the minimum sample size was determined to be 40 for each group and 80 patients in total in order to find a significant difference [9].
Statistical Analysis
The data was expressed as mean with standard deviation and median (min-max) values or frequency (percentage) for overall variables. Normality distribution was assessed using the Shapiro Wilk test. Quantitative data was analyzed using the independent samples t-test and the Mann Whitney U-test, where appropriate. Qualitative data was analyzed with the Pearson chi-square or the Fisher’s exact test, where appropriate. A value of P < 0.05 was considered as significant. IBM SPSS Statistics version 25.0 for Windows was used for the statistical analysis.