|Year : 2015 | Volume
| Issue : 2 | Page : 244-246
Does the self-pressurizing Air Q produce less postoperative sore throat compared with the classic laryngeal mask airway? A randomized controlled double-blind study
Mohamed I.S. El-Ahl MD
Department of Anaesthesia, Ain Shams University, Cairo, Egypt
|Date of Submission||17-Oct-2014|
|Date of Acceptance||30-Jan-2015|
|Date of Web Publication||8-May-2015|
Mohamed I.S. El-Ahl
Department of Anaesthesia, Ain Shams University, Cairo 7400
Source of Support: None, Conflict of Interest: None
The aim of the study was to evaluate the risk for postoperative sore throat (POST) using the self-pressurizing Air Q compared with that using classic laryngeal mask airway (LMA).
Patients and methods
A total of 150 patients were included in this double-blind prospective study. After induction of general anesthesia, the airway was maintained with an Air Q device (in group Q, 75 patients) and with a classic LMA (in group C, 75 patients). The POST was evaluated and graded (on the basis of its severity) within 20 min in the recovery room and 24 h after surgery.
The incidence of POST and its severity were comparable in both groups.
Despite the self-pressurizing cuff of Air Q, there was no reduction in the POST incidence or severity compared with that using classic LMA.
Keywords: air Q, classic laryngeal mask airway, sore throat
|How to cite this article:|
El-Ahl MI. Does the self-pressurizing Air Q produce less postoperative sore throat compared with the classic laryngeal mask airway? A randomized controlled double-blind study. Ain-Shams J Anaesthesiol 2015;8:244-6
|How to cite this URL:|
El-Ahl MI. Does the self-pressurizing Air Q produce less postoperative sore throat compared with the classic laryngeal mask airway? A randomized controlled double-blind study. Ain-Shams J Anaesthesiol [serial online] 2015 [cited 2021 Oct 26];8:244-6. Available from: http://www.asja.eg.net/text.asp?2015/8/2/244/156700
| Introduction|| |
In the present healthcare climate, there is an ever growing emphasis on patient's safety. There is special concern to minimize iatrogenic complications arising during patient care  . Postoperative sore throat (POST) is a common adverse effect after general anesthesia  . It occurs after intubation, insertion of supraglottic airway devices, or even with facemask placement  . However, its frequency varies with the type of the airway device. The Air Q intubating laryngeal airway is a supraglottic airway device that seems to be an effective airway device, as well as a conduit for intubation, in both anticipated and unanticipated difficult intubation  . It is a relatively new device, and its associated risk of POST is still unclear. Because of its characteristics (including the lower intracuff pressure), in theory it should have a lower incidence of POST compared with other supraglottic airway devices. The aim of the study was to evaluate the risk for POST using Air Q compared with that of using classic laryngeal mask airway (LMA).
| Patients and methods|| |
This prospective controlled randomized double-blind study was approved by the Research and Ethical Committee of Burjeel Hospital, Abu Dhabi, United Arab Emirates, and was conducted from March to September 2014. A total of 150 patients who were scheduled for lower limb orthopedic surgeries under general anesthesia were included in this study, and written informed consent was obtained. Patients with ASA III or more were excluded. The patients were randomly allocated into two equal groups, Q and C. The patients' allocation was performed by block randomization using the package 'blockrand' in R (R Foundation for statistical computing, Vienna, Austria). Opaque sealed envelopes were used for concealment of randomized allocation. The airway was maintained with an Air Q device in group Q and with classic LMA in group C.
In the preoperative room, the patients received 1-2 mg midazolam after insertion of an intravenous line. On arrival to the operating room, standard monitoring lines were placed. Preoxygenation was performed. General anesthesia was induced using 1 mcg/kg of remifentanil over at least 30 s and 2-3 mg/kg of propofol, and it was maintained with 2-3% sevoflurane in 50% of oxygen in air with remifentanil maintenance infusion at 0.5-20 mcg/kg. After loss of consciousness, 0.1 mg/kg cisatracurium was injected. After 2 min, the assigned devices, the self-pressurizing Air Q (Mercury Medical, Clearwater, Florida, USA) in group Q and classic LMA (Laryngeal Mask Company Limited, Le Roche, Victoria, Mahe, Seychelles) in group C, were placed. Before placement, the device (LMA) was tested for leak. Both devices were lubricated at the tips and posterior surfaces with water-soluble surgical gel. Viscous lidocaine and/or other topical anesthetics were not used. The size of the device was chosen according to manufacturer's instructions based on body weight, and the volume of LMA cuff inflation was also chosen according to the manufacturer's instructions.
The adequacy of ventilation was assessed with the following:
Controlled mechanical ventilation was adjusted to maintain normocapnia. Femoral and/or sciatic nerve block analgesia was performed under US guidance. At the end of the procedure, the neuromuscular blockade was reversed with neostigmine 0.05 mg/kg and atropine 0.02 mg/kg. After regaining of consciousness and motor power, the device was removed without deflation and without suctioning. No steroids or nonsteroidal analgesics were given during the perioperative period. Only opioids were given if required, in case the nerve block performed was inadequate or unsuccessful.
- Observation of chest inflation,
- The end-tidal carbon dioxide,
- System leak alarm, and
- SpO 2. If the ventilation was not adequate even after simple manipulations, the device was reinserted (or replaced) and the patient was excluded and replaced.
POST was evaluated and graded within 20 min in the recovery room and 24 h after surgery by the assistant and the ward nurse who were unaware of the used device. The severity of sore throat was graded as follows: 0, no sore throat; 1, minimal; 2, moderate; 3, severe.
On the basis of previous studies , , 149 patients were required to detect a 5% difference between the two groups with a power of 95% and an α error of 0.05. Ten patients (six in group Q and four in group C) required reinsertion of the corresponding airway device. These patients were excluded and replaced. The incidences and scores of sore throat were compared using the Fisher exact test and the Pearson's χ2 tests, respectively. Continuous data were compared using the unpaired student t-test. The sample size was calculated using G*Power 188.8.131.52 (Department of Psychology, Heinrich-Heine University, Dusseldorf, Germany), whereas all other data were analyzed using Graph Pad InStat, version 3.00 for Windows (Graph Pad Inc., San Diego, California, USA). All results are presented as mean (SD), median (interquartile ratio), or frequency, as appropriate. A P-value of 0.05 or less was considered to be significant.
| Results|| |
A total of 150 patients participated in this study, and their characteristics were comparable in both groups ([Table 1]). The frequencies of POST within 20 min and after 24 h were comparable in groups Q and C (13 vs. 23; P = 0.85 and 3 vs. 2; P = 1 respectively). The severity of POST was also comparable between the two groups ([Figure 1]) at 20 min (P = 0.257) and 24 h after surgery (P = 0.367).
|Figure 1: The severity of postoperative sore throat. (a) Within 20 min after operation; (b) after 24 h.|
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| Discussion|| |
This study showed that the incidence of POST and its severity were comparable in both groups in the postanesthesia care unit and 24 h postoperatively.
Sore throat, in its simplest form, is a lay description of pharyngitis. This in itself can have a variety of causes; however, sore throat may also include a variety of symptoms, including laryngitis, tracheitis, hoarseness, cough, or dysphagia  . POST is one of the most frequent postoperative complications; its incidence ranges from 20 to 90% in some studies ,,,,,,,, . Several factors may affect the incidence of POST, including the use of anticholinergic and nitrous oxide, the insertion technique, the cuff pressure, and lidocaine lubrication  .
The frequency and severity of laryngopharyngeal complications were also related to the type of airway device used  . In LMA, the inflation can induce sufficient compression to cause reduction in pharyngeal mucosal blood flow and induce direct tissue trauma, as has also been reported for the tracheal tube  . The Air Q intubating laryngeal airway is a new supraglottic airway device with unique design, which includes a large airway tube inner diameter, a short tube length, and a tethered removable standard 15 mm circuit adapter. Its cuff pressure is self-regulated as it is no longer a closed airspace  . The self-pressurized cuff is a new concept for supraglottic airways and may have some clinical advantages when compared with other cuffed supraglottic airways. First, the intracuff pressure is determined by the airway pressures, because of the equalization of pressures with the movement of gases between the cuff and airway. Second, the lower intracuff pressure is maintained overall as a result of being limited by the peak airway pressure (which is the highest pressure exerted during inspiration).
Third, by not exceeding peak airway pressures, the balance between intracuff pressures and the airway seal of the device may be optimized at lower pressure. Therefore, the overinflation-related risks including sore throat, neuropraxic injury, and gastric insufflations should be reduced with the Air Q , .
However, our results contradicted this hypothesis and showed that the incidence of POST with Air Q is similar to that in LMA. This suggests that POST may be caused by other causes rather than the cuff inflation. This is supported by a study of Higgins et al.  , in which POST occurred with facemask placement. Moreover, in previous studies, there was no significant difference in the incidence of sore throat when comparing the LMA cuff pressures of 41 cmH 2 O (30 mmHg) with that of 244 cmH 2 O (180 mmHg)  . In contrast, in another study, inflation of LMA cuff with low volume of air was shown to decrease the incidence of POST in ventilated patients  .
The type of patients (as regards their age and sex) and the type of surgery in the current study may limit the general application of our results; as these factors may affect the incidence of POST  . The incidence of POST also varies on the basis of definition and type of symptoms assessed  . Finally, the cause of POST is still unclear and requires scrutiny to reveal it.
| Conclusion|| |
Despite the self-pressurizing cuff of Air Q, there was no reduction in POST incidence or severity compared with that using classic LMA.
| Acknowledgements|| |
Conflicts of interest
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