|Year : 2015 | Volume
| Issue : 4 | Page : 101-110
Intubating laryngeal mask airway and air-Q for blind tracheal intubation
Moustafa Abo Shamaa, Doaa Abo Alia, Mohamed El-Sayed
Department of Anaesthesiology and Surgical Intensive Care, Faculty of Medicine, University of Alexandria, Alexandria, Egypt
|Date of Submission||16-Oct-2004|
|Date of Acceptance||15-Nov-2014|
|Date of Web Publication||17-Mar-2016|
Moustafa Abo Shamaa
Department of Anaesthesia, Alexandria Faculty of Medicine, Barid El Messalah, Alexandria
Source of Support: None, Conflict of Interest: None
Airway management remains an important problem in the practice of anesthesia. The present study was carried out to compare intubating laryngeal mask airway (ILMA) and air-Q for blind tracheal intubation during surgical procedures under general anesthesia.
Materials and methods
This study was carried out on 70 adult patients scheduled for elective surgical procedures under general anesthesia with controlled ventilation such as gynecological, orthopedic, ophthalmic, or general surgery lasting up to 2 h.
Data were collected on airway assessment, hemodynamic changes, insertion time of the device and the endotracheal tube, number of attempts of blind tracheal intubation, ease of insertion, and complications.
Airway assessment parameters were similar in patients of both groups. The incidence of hemodynamic changes was significantly higher in the air-Q group than the fastrack group and the insertion time of the endotracheal tube as well as the percentage of ease of insertion in group I (fastrack) showed a statistically significantly higher value than group II (air-Q). However, there was no statistically significant difference between the two groups in the number of insertion attempts (a success rate of 88.57% for the fastrack vs. a success rate of 82.86% for the air-Q) and the complications.
Both the fastrack and the air-Q are suitable devices for blind tracheal intubation. The fastrack has a higher success rate in terms of blind tracheal intubation than the air-Q.
Keywords: air-Q, blind endotracheal intubation, intubating laryngeal mask airway
|How to cite this article:|
Shamaa MA, Alia DA, El-Sayed M. Intubating laryngeal mask airway and air-Q for blind tracheal intubation. Res Opin Anesth Intensive Care 2015;2:101-10
|How to cite this URL:|
Shamaa MA, Alia DA, El-Sayed M. Intubating laryngeal mask airway and air-Q for blind tracheal intubation. Res Opin Anesth Intensive Care [serial online] 2015 [cited 2018 May 21];2:101-10. Available from: http://www.roaic.eg.net/text.asp?2015/2/4/101/178901
| Introduction|| |
Airway management remains an important problem in the practice of anesthesia. Interruption of gas exchange, for even a few minutes, can result in catastrophic outcomes such as brain damage or death. Closed claims analysis has found that the vast majority (85%) of airway-related events involve brain damage or death, and as many as one-third of deaths attributable solely to anesthesia have been related to an inability to maintain a patent airway .
As anesthesiologists spend a considerable proportion of their career maintaining the airway. Theoretically, every anesthesiologist should be familiar with and well practiced in a variety of airway techniques that are available so that when an airway problem occurs, it can be managed with a solid armamentarium of information and experience. However, with the rapid advancements in airway management technology, many of the newer airway devices are foreign to most anesthesiologists.
In the last few years, a number of supraglottic airway devices have been introduced in the clinical practice of airway management, in an attempt to offer a simple and effective alternative to the endotracheal intubation.
Supraglottic airway devices are devices that ventilate patients by delivering anesthetic gases/oxygen above the level of the vocal cords and are designed to overcome the disadvantages of endotracheal intubation such as soft tissue, tooth, vocal cords, laryngeal and tracheal damage, exaggerated hemodynamic response, barotrauma, etc.
The advantages of the supraglottic airway devices include avoidance of laryngoscopy, less invasiveness for the respiratory tract, better tolerance by the patients, increased ease of placement, improved hemodynamic stability in emergence, less coughing, less sore throat, hands-free airway, and easier placement by inexperienced personnel.
The American Society of Anaesthesiologists' Task Force on Management of the Difficult Airway suggests considering the use of supraglottic airway devices [such as laryngeal mask airway (LAM) and Combitube] when intubation problems occur in patients with a previously unrecognized difficult airway, especially in a 'cannot ventilate, cannot intubate' situation.
The European Difficult Airway Society suggests using the LAM or the intubating laryngeal mask in an unanticipated difficult tracheal intubation .
The LMA, originally described by Brain, has been described as the missing link between the facemask and the tracheal tube and it has gained widespread popularity. The proseal laryngeal mask airway is a new LAM with a modified cuff designed to improve its seal and a drainage tube for gastric tube placement. The single-use Portex Soft Seal Laryngeal Mask is a new supraglottic device similar to the single-use LMA unique. The Esophageal-Tracheal Combitube is an easily inserted double-lumen/double-balloon supraglottic airway device that allows for ventilation independent of its position either in the esophagus or in the trachea. Blind insertion results in successful esophageal intubation in almost all patients. The EasyTube is a new disposable, polyvinyl-chloride, double-lumen, latex-free, supraglottic airway device. It has a design that is similar to the Combitube, intended to be more user friendly. The laryngeal tube is an airway tube with two low-pressure cuffs (proximal and distal) and two oval apertures placed between them that allows ventilation.
Fastrack, a modification of the LMA, is in use from 1997, designed as a conduit for tracheal intubation, and has a success rate for endotracheal intubation of ~93%. It has an epiglottic elevator bar at the mask aperture and a rigid (stainless steel) anatomically curved shaft that follows the anatomical curve of the palate and the posterior pharyngeal wall . The air-Q Intubating Laryngeal Airway (ILA; Cookgas LLC, Mercury Medical, Clearwater, Florida, USA) is a new supraglottic airway device that, in addition to allowing for airway maintenance under general anesthesia, also allows for tracheal intubation with a cuffed endotracheal tube (ETT) (up to 8.5 mm IDs) blindly or fiberoptic guided in both adults and pediatric patients .
The present study was carried out to compare ILMA (fastrack) and air-Q for blind tracheal intubation during surgical procedures under general anesthesia.
| Materials and methods|| |
This study was carried out in Alexandria Main University Hospitals on 70 adult patients scheduled for elective surgical procedures under general anesthesia with controlled ventilation.
- Patients belonging to ASA physical status I or II.
- Patients with BMI less than 40 kg/m 2 .
- Mallampati classification I or II.
Patients were excluded if they fulfilled one of the following criteria:
- Morbid obesity (BMI>40 kg/m 2 ).
- History of gastric regurgitation, pregnancy, heartburn.
- Full stomach.
- Pharyngeal or laryngeal pathology.
- Mouth opening of less than 3.8 cm.
- Suspected difficult airway as judged by airway assessment.
After approval of the Local Ethical Committee and obtaining an informed written consent from every patient, patients were categorized randomly into two equal groups (35 patients each) using the closed-envelope method:
- Group I: the ILMA (fastrack) was used for blind tracheal intubation
- Group II: the air-Q was used for blind tracheal intubation.
All patients included in this study were assessed thoroughly as follows:
Detailed assessment of medical and surgical history, complete clinical examination, routine laboratory investigations (complete blood picture, renal function tests, coagulation profile, and fasting blood sugar), and airway assessment, which included the following:
- Modified Mallampati classification====The airway was classified according to the structures seen as follows:
- Class I, soft palate, uvula, pillars.
- Class II, soft palate, uvula.
- Class III, soft palate, base of uvula.
- Class IV, soft palate not visible at all.
- Thyromental distance: the distance between the prominence of the thyroid cartilage and the bony point of the chin, measured with the head fully extended on the neck. It is ideally more than 6.5 cm.
- Sternomental distance: the distance between the upper border of the manubrium sterni and the bony point of the mentum, measured with the head fully extended on the neck, in the seated position. It is ideally more than 12.5 cm.
- Mouth opening (interincisor gap): the distance between the upper and the lower incisors and the mouth is maximally opened. It is ideally more than 3.8 cm.
- Ability to prognath: the capacity to bring the lower incisors in front of the upper ones.
- Head and neck movement: measurement of the range of movement of the head and neck by instructing the patient to fully extend them from the full flexion position. It is measured in degrees.
On arrival to the operating room, patients were connected to a multichannel monitor for the continuous display of electrocardiograph, heart rate, noninvasive arterial blood pressure, and pulse oximetery. An intravenous access was established for all patients and a slow infusion of ringer's solution was commenced. A laryngoscope and a proper size ETT were available for any case of failure of blind tracheal intubation through the supraglottic airway device used.
Ten minutes before induction of anesthesia, all patients were premedicated by intravenous midazolam 0.02 mg/kg. Patients were preoxygenated with 100% oxygen for 3 min.
Induction of anesthesia was carried out by an intravenous administration of fentanyl 1 μg/kg, lidocaine 1.5 mg/kg, and propofol 2 mg/kg. After loss of verbal communication, 0.2 mg/kg cisatracurium was administered.
Controlled ventilation was provided through a face mask with 100% O 2 and isoflurane (1-2%) for 3 min and then the selected airway device was inserted. Manual positive pressure ventilation was initiated. Correct insertion of the device was assessed by the absence of audible leak and adequate chest expansion and the appearance of capnograph waveform.
If it was not possible to ventilate the lung, the following adjustments were allowed (neck extension or flexion, jaw thrust, and gentle pushing or pulling of the device) . After ventilation was established, the investigator attempted to pass the tracheal tube blindly. A 7.0-mm tracheal tube was used with the ILMA fastrack and with the air-Q.
A maximum of two blind attempts were allowed, and the number of attempts was recorded by a research assistant. If a second attempt was required, the manufacturer's instructions were followed. For the ILMA (fastrack), this means applying gentle rotation of the handle in and out and side to side until ventilation was optimized, and then the handle was gently lifted anteriorly and the tracheal tube was reinserted . For the air-Q, the device was withdrawn 5-8 cm with mandibular lift during reinsertion of the air-Q .
Irrespective of the device used, the patient's lungs were ventilated between attempts if needed and additional boluses of propofol 0.5 mg/kg could be administered until a level of anesthesia adequate for placement was achieved. If, after two attempts, the tracheal tube was not inserted properly, or the supraglottic device was not placed, or oxygen saturation decreased to 90%, direct laryngoscopy was utilized . The supraglottic airway was immediately removed after confirmation of successful intubation. Endotracheal intubation was confirmed by the appearance of a capnograph waveform, adequate chest expansion, and by auscultation of bilateral equal air entry.
After confirming the establishment of an effective airway, the endotracheal tube was connected to a circle breathing system and controlled ventilation was adjusted to deliver 7 ml/kg body weight at a rate of 10 breaths/min with an I : E ratio 1 : 2. Anesthesia was maintained by isoflurane (1-2%) in 100% oxygen. At the end of surgery, the isoflurane vaporizer was shut off and the muscle relaxant was reversed with neostigmine 0.04 mg/kg and atropine 0.02 mg/kg. The tube was removed after the patient regained consciousness, breathed spontaneously, and responded to verbal commands.
The hemodynamic parameters (heart rate, mean arterial blood pressure, and oxygen saturation) were monitored continuously and recorded at the following time points: before the induction of anesthesia, after the induction of anesthesia, before the insertion of the airway device, after the insertion of the airway device, after blind tracheal intubation, and 5 min and 10 min after intubation.
The insertion times were also recorded in seconds including time to successful insertion of the airway device, insertion time of the tracheal tube through each device, and the total duration from the time the supraglottic airway was placed until it was removed, with correct placement of the tracheal tube verified by capnography.
The number of attempts at blind tracheal intubation through each device was counted and the ease of insertion of each device was assessed and rated as follows:
- Straight forward: when insertion was successful at the first attempt and within 15 s.
- Slightly difficult: if insertion took more than 15 s.
- Obviously difficult: if more than one attempt of insertion was necessary.
- Failure: if supraglottic device insertion was impossible and ETT was necessary to be inserted.
Immediately after removal, the device was inspected for traces of blood indicating airway trauma. Postoperatively and before leaving the PACU, the patients were asked whether they had sore throat, dysphagia, and dysphonia.
All the data were analyzed using the statistical package for the social science version 13 (IBM corporation 2009, USA). Demographic and clinical data from the two groups were compared using a two-tailed t-test and the c2 -test as appropriate. Intergroup and intragroup differences among the hemodynamic variables recorded over time were analyzed using two-way analysis of variance for repeated measures, paired, and unpaired t-tests with Bonferroni post-test analysis as appropriate. All quantitative data are expressed as mean ± SD. A P value less than 0.05 was considered statistically significant.
| Results|| |
All 70 patients completed the study. There was no difference between the two groups with respect to demographic data and parameters of airway assessment [Table 1].
On comparing the two groups in the hemodynamic changes, the heart rate of group II (ir-Q) after intubation showed a statistically significantly higher value than that of group I (fastrack) (P = 0.003) [Table 2], [Figure 1] and the mean arterial blood pressure of group II (air-Q) after insertion of the device, after intubation, 5 min after intubation, and 10 min after intubation showed statistically significantly higher values than those of group I (fastrack) (P < 0.001) [Table 3], [Figure 2]. Also, the percentage of oxygen saturation after intubation in group I (fastrack) showed statistically significantly higher values than group II (air-Q) (P = 0.017) [Table 4], [Figure 3].
|Figure 1: Comparison between the two groups studied in heart rate (beats/min).|
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|Figure 2: Comparison between the two groups in the mean arterial blood pressure (mmHg).|
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|Figure 3: Comparison between the two groups in the oxygen satu ration (SpO2%).|
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|Table 2: Comparison between the groups studied in heart rate (beats/min)|
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|Table 3: Comparison between the groups studied in the mean blood pressure (mmHg)|
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The insertion time of the device among the patients of group I (fastrack) ranged from 9 to 34 s, with a mean of 22.57 ± 6.67 s, the insertion time of the endotracheal tube through the device ranged from 32 to 63 s, with a mean 47.58 ± 10.53, and the total time ranged from 69 to 125, with a mean 93.55 ± 19.09.
However, the insertion time of the device among the patients of group II (air-Q) ranged from 16 to 37 s, with a mean of 23.91 ± 5.27 s, the insertion time of the endotracheal tube through the device ranged from 27 to 58 s, with a mean 38.86 ± 9.46, and the total time ranged from 76 to 184, with a mean 121.69 ± 38.29.
There was no statistically significant difference between the two groups in the mean insertion time of the devices (P = 0.353). However, the insertion time of the endotracheal tube in group I (fastrack) showed a statistically significantly higher value than group II (air-Q) (P = 0.001) and the total insertion time in group II (air-Q) showed a statistically significantly higher value than group I (fastrack) (P = 0.001) [Table 5], [Figure 4].
|Figure 4: Comparison between the two groups studied in insertion time (s).|
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In terms of the number of insertion attempts, in group I (fastrack), the ETT was inserted successfully through the device (success rate 88.57%) at the first attempt in 25 patients (80.6%); it required a second attempt in six patients (19.4%). However, in group II (air-Q), the ETT was inserted successfully through the device (success rate 82.86%) at the first attempt in 18 patients (62.1%); it required a second attempt in eleven patients (37.9%).
On comparing the attempts individually, there was no statistically significant difference between the two groups in the number of insertion attempts (P = 0.111) [Figure 5].
|Figure 5: Comparison between the two groups studied in the number of attempts.|
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In terms of the ease of insertion, there was a statistically significant difference in the ease of insertion between the two groups (P = 0.011) [Figure 6], [Table 6].
|Figure 6: Comparison between the two groups studied in ease of insertion.|
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In terms of the complications, there was no statistically significant difference between the two groups [Figure 7], [Table 7].
| Discussion|| |
The main responsibility of the anesthesiologist is to provide adequate ventilation to the patient. The most vital element in providing functional respiration is the airway. Management of the airway has come a long way from the development of endotracheal intubation by Macewen in 1880 to the present-day use of modern and sophisticated devices. The wide variety of airway armamentarium available today may broadly be classified as intraglottic and extraglottic airway devices, which are used to protect the airway in both elective and emergency situations. New extraglottic airway devices have also been described at a rate of one per year for the last 25 years, increasing to two per year since the turn of the century.
The ILMA (fastrack) is a supraglottic airway device first introduced in 1997 and designed for anticipated or unanticipated difficult airway situations and for cardiopulmonary resuscitation; the ILMA Fastrach facilitates continuous ventilation and intubation, reducing the likelihood of desaturation. The air-Q ILA is a new supraglottic airway device that may overcome some limitations inherent to the classic LAM for tracheal intubation.
The aim of the present study was to compare the two devices in hemodynamic response, insertion parameters, and the incidence of complications. The study was carried out in Alexandria University Hospitals on 70 adult patients scheduled for elective surgical procedures under general anesthesia with controlled ventilation such as gynecological, orthopedic, or general surgery lasting up to 2 h. The sample size was approved to be sufficient by the department of statistics, medical research institute, University of Alexandria.
The patients were divided randomly into two equal groups, 35 patients each, using the closed-envelope method.
Group I: the ILMA (fastrack) was used for blind tracheal intubation.
Group II: the air-Q was used for blind tracheal intubation.
In terms of age, body weight, and sex distribution of the patients in the present study, there were no statistically significant differences between the two groups.
Analysis of the parameters used in the present study to assess the airway of the patients in the two groups did not show any statistically significant differences between them in the modified Mallampati classification, the thyromental distance, the sternomental distance, the interincisor gap, the ability to prognath, or the maximum range of head and neck movement.
All the airway assessment parameters in both groups in the present study did not show any values below the cut-off limits for the prediction of difficult airway as reported by Merah et al.  and El-Ganzouri et al.  so that the airway assessment parameters could not affect the results obtained with each device insertion and endotracheal intubation through it .
When the cardiovascular findings were analyzed in the present study and on comparing the two groups, the heart rate and the mean arterial blood pressure values showed a statistically significant decrease just before the airway device insertion in both groups compared with the values before the induction of anesthesia. This may have been because of the usage of propofol in the induction of anesthesia, which is often associated with a significant decrease in the arterial blood pressure and in the heart rate, attributed to the decrease in the peripheral vascular resistance or in the cardiac output caused by a combination of venous and arterial vasodilatation, impaired baroreflex mechanisms, and depression of myocardial contractility .
Propofol was selected because it is frequently used to induce anesthesia when inserting the extratracheal airways as it induces anesthesia rapidly and inhibits the protective upper airway reflexes .
In the present study, the mean arterial blood pressure but not the heart rate in group II (air-Q) showed statistically significantly higher values after the insertion of the air-Q than that with the fastrack in group I.
The heart rate and the mean arterial blood pressure in group II (air-Q) showed statistically significantly higher values just after the ETT insertion through the air-Q rather than just after the ETT insertion through the fastrack in group I. At all the other time points of comparison between the fastrack and the air-Q in the hemodynamic variables, there were no statistically significant differences.
This may be attributed to the more exaggerated pressor response shown by the air-Q during its insertion and ETT intubation rather than by the fastrack, related mainly to the difference in placement maneuvers of the two airway devices. In fact, when inserting the air-Q, the epiglottis may be downfolded and 4-5 cm device withdrawal with jaw lift then reinsertion of the device again improve its fitting and abolish the resistance felt on ETT intubation. Also reversing the sniffing position to the neutral position to minimize the mask leak is another useful maneuver. All these maneuvers increase the pressor response of the air-Q device .
In agreement with this, Abdel-Halim et al.  reported a statistically significantly higher heart rate after ETT insertion in the air-Q rather than that in the fastrack, but did not report any statistically significant differences in the blood pressure.
In terms of the percentage of oxygen saturation, there was a statistically significantly higher value of the mean percentage of oxygen saturation after ETT insertion in group I (fastrack) than group II (air-Q), attributed most probably to the generously lubricated inner tube of the air-Q to overcome the resistance felt on ETT insertion evidenced by auscultation of scattered secretory crepitations in patients of group II, especially those with more than one intubation attempt, and thus prolonged total insertion time .
In agreement with this, Jagannathan et al.  reported Oxygen desaturation in six of 34 patients using the air-Q ILA as a conduit for blind tracheal intubation in pediatric patients with a difficult airway.
On analyzing the insertion measurements and in terms of the insertion time of the airway devices in the present study, the air-Q device insertion time (23.91 ± 5.27) was longer than the fastrack device insertion time (22.57 ± 6.67), but statistically nonsignificant, whereas the ETT insertion time through the fastrack (47.58 ± 10.53) was statistically longer than the ETT insertion through the air-Q (38.86 ± 9.46). However, there was a statistically significantly longer total duration of insertion of the air-Q (121.69 ± 38.29 s) in group II than that of the fastrack (93.55 ± 19.09 s) in group I. This may be attributed to the more manipulations needed and the more ETT insertion attempts in the air-Q rather than those in the fastrack .
In relation to this, Abdel-Halim et al.  reported shorter time of device insertion as well as ETT insertion in group II (air-Q) (13.300 ± 3.471, 33.50 ± 6.79, respectively) than in group I (fastrack) (19.640 ± 4.737, 39.50 ± 6.56, respectively), but the total time was not measured.
In terms of the number of insertion attempts, in group I (fastrack), the ETT was inserted successfully through the device (success rate 88.57%) at the first attempt in 25 patients (80.6%) and required a second attempt in six patients (19.4%). A successful ETT insertion could not be established in the second attempt and an ETT was inserted using direct laryngoscopy to secure the airway in four patients.
However, in group II (air-Q), the ETT was inserted successfully through the device (success rate 82.86%) at the first attempt in 18 patients (62.1%) and a second attempt was required in 11 patients (37.9%). A successful ETT insertion could not be established in the second attempt; thus, an ETT was inserted using direct laryngoscopy to secure the airway in six patients. There was no statistically significant difference between the two groups in the number of insertion attempts.
In relation to this, El-Ganzouri et al.  concluded that air-Q is a good facilitator for blind intubation. It enabled successful blind intubation in 70% of the patients versus 97.5% using the fiberoptic technique. However, Halwagi et al.  reported successful tracheal intubation at the first attempt in 69% of patients with the i-gel and 74% of patients with the LMA Fastrach, together with an overall intubation success rate lower with the use of the i-gel than that with the use of the LMA Fastrach (73 vs. 91%).
In terms of the ease of insertion, in group I (fastrack), ease of insertion of the device was straight forward in 35 patients (100%), whereas in group II (air-Q), ease of insertion of the device was straightforward in 28 patients (80%) and slightly difficult in seven patients (20%) .
In contrast, Abdel-Halim et al.  reported that air-Q could be inserted easily in 94% of the patients and it showed moderate ease of insertion in 6%; however, the fastrack inserted easily in 84% of the patients and showed a moderate ease of insertion in 16%.
When the complications resulting from the use of the fastrack and the air-Q in the present study were analyzed, it was found that air-Q was more traumatizing to the airway than the fastrack evidenced by the presence of traces of blood on the mask in seven patients (20%) in the air-Q whereas this was observed in only five patients (14.29%) in the fastrack. Also, sore throat and dysphagia because of mucosal injuries were present in 10 patients (28.57%) and in five patients (14.29%), respectively, in the air-Q, but they were present in eight patients (22.86%) and in three patients (8.57%), respectively, in the fastrack.
This may be attributed to more maneuvers needed and more attempts required to optimize the air-Q fitting or to overcome the resistance felt on ETT insertion that occurs because of epiglottis downfolding or dislodgement into the air-Q keyhole opening. The most important maneuver is deflation the air-Q cuff, its withdrawal 5 cm outward, reinsertion of the device, and re-inflation of the cuff .
In agreement with this, Bashandy et al.  reported that the incidence of airway injury was more frequent in the air-Q group than in the direct laryngoscopy group (6 of 30 vs. 0 of 30; P < 0.05). Sore throat was correlated with airway trauma as evident from repeated attempts and/or observation of blood on the air-Q. Also, Badawi et al.  reported that sore throat was graded as mild in 20 patients and moderate in five patients in the air-Q (25/80, 31.25%), whereas in fastrack, it was graded as mild in 13 patients and moderate in seven patients (20/80, 25%).
| Conclusion|| |
Both the fastrack and the air-Q are suitable devices for blind tracheal intubation. The fastrack has a higher success rate for blind tracheal intubation than the air-Q.
| Acknowledgements|| |
Conflicts of interest
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]