Age-related differences in the performance of the self-pressurising air-Q intubating laryngeal airway: a prospective comparative study

Abstract

Purpose

The clinical performance of supraglottic airway devices (SADs) may be affected by anatomical and physiological changes of the oropharyngeal structure that occur with aging. We aimed to evaluate the performance of self-pressurized air-Q intubating laryngeal airway (air-Q SP) in young, middle-aged, and elderly patient groups undergoing elective surgery under general anesthesia with the use of an air-Q SP.

Methods

A total of 153 patients, aged 18–85 years, with American Society of Anesthesiologists physical status I–III who underwent urological surgery were included in this prospective, comparative study. Patients were equally allocated into groups according to parient age, Group Young: 18–40 years; Group Middle-aged: 41–64 years and Group Elderly: 65–85 years. The primary outcome was oropharyngeal leak pressure (OLP); SAD insertion time, first-attempt success rate, ease of insertion, maneuvers required for successful ventilation, fiberoptic grading of the glottic view, peak inspiratory pressure (PIP) and postoperative complications were also assessed. Analysis of variance was used for comparisons between patient groups, and adjusted p values were reported in the post hoc tests. Multivariate regression analyses were performed to evaluate factors associated with OLP values.

Results

The median [IQR] OLP values were 29 [26–35] cm H₂O, 24 [14–39] cm H₂O and 26 [21–29] cm H₂O in Groups Young, Middle-aged and Elderly respectively. The OLP values in Group Young were significantly higher than those in Group Middle-aged and Group Elderly (p = 0.001, and p = 0.014 respectively). Air-Q SP insertion in Group Young was significantly faster and easier, required fewer maneuvers, provided better fiberoptic views, lower PIP and higher postoperative first hour dysphagia and dysphonia rate. Multivariate analysis revaled that BMI was associated with OLP (OR 0.335, 95%CI) (R² = 0.111, F = 4.639, p = 0.001). A negative correlation was found between patients’ age and OLP values (r = -0.239, p = 0.003).

Conclusion

Compared with the middle-aged and elderly groups, the young group had superior sealing and insertion characteristics with use of air-Q SP but transient early postoperative dysphagia and dysphonia. The air-Q SP was sufficient for adequate ventilation in all groups.

Introductıon

Supraglottic airway devices (SADs) are used to establish and maintain the airway during surgical procedures or in emergency situations, both for the management of normal and anticipated or unanticipated difficult airways [1]. Parapharyngeal fat deposition increases with age and leads to pharyngeal collapse in elderly patients [2]. In addition, aging is associated with a reduction in upper esophageal sphincter resting pressure, and therefore these anatomical and physiological changes related to aging may affect the clinical performance of SADs [3]. In an earlier study, Kim et al. evaluated the performance of the classic laryngeal mask airway in younger and older patients. The authors reported a greater first-pass ventilation success rate in younger individuals, while older patients required increased manipulation and prolonged insertion duration [4]. There are limited studies investigating the performance of other SADs across different age groups.

The self-pressurized air-Q intubating laryngeal airway (air-Q SP) has an opening between the airway tube and the proximal cuff, which allows the cuff pressure to self-regulate its pressure relative to the surrounding structures such as the oropharynx and larynx [5, 6]. Therefore, once the air-Q SP is inserted into the patient’s mouth, cuff inflation with air is not required. This feature has the potential to reduce complications known to result from excessive cuff pressure, including mucosal injury, nerve damage, and postoperative sore throat [7].

Previous studies have evaluated the clinical performance of air-Q SP in pediatric [8] and elderly [9] patients; however, no study has compared its performance across different age groups. We hypothesed that the self-pressurized cuff feature of the device might be useful to overcome the age related issues of SADs. The aim of this study was to evaluate the performance of the air-Q SP in young (18–40 years), middle-aged (40–64 years), and elderly (65–85 years) patients undergoing elective urological surgery under general anesthesia with neuromuscular blockade in whom the air-Q SP was used. The primary outcome measure is the oropharyngeal leak pressure (OLP); SAD insertion time, first-attempt success rate, fiberoptic grade of glottic visualization, ease of insertion, peak inspiratory pressure (PIP) and intraoperative and postoperative complications are the secondary outcome measures.

Metod

This prospective comparative study was approved by the Ethics Committee of Ankara Etlik City Hospital (AEŞH-BADEK-2024-490) and registered at http://clinicaltrials.gov (NCT06563583), and complies with the ethical standarts of the Helsinki Declaration-2013. Patients scheduled for elective urological surgery under general anesthesia with an expected duration of less than two hours, were consecutively enrolled at the Ankara Etlik City Hospital Anesthesiology and Reanimation Preoperative Evaluation Clinic between September 2024 and October 2024. Patients were eligible if they met the following criteria: classified as in American Society of Anesthesiologists (ASA) physical status I–III, aged 18–85 years, and writted informed consent was obtained. Patients having known or predicted difficult airway (Mallampati class 4, mouth opening < 3 cm, or thyromental distance < 6 cm), Body Mass Index (BMI) > 40 kg/m², gastroesophageal reflux, asthma, chronic obstructive pulmonary disease; recent upper respiratory tract infection, neuromuscular disease, previous head and neck surgery, pregnancy, upper gastrointestinal tract pathology, operations lasting longer than two hours, and patients undergoing reoperation on the same day were excluded. Poor dentition was defined as missing, loose, or broken teeth, and such patients were included in the study. Patients with complete edentulism were excluded.

During the preoperative evaluation, patients who met the inclusion criteria were recruited by the investigators (KZ, KG). Eligible patients were assigned to study groups according to age: Group Young: patients aged 18–40 years; Group Middle-Aged: patients aged 41–64 years; and Group Elderly: patients aged 65–85 years [4]. Upon arrival in the operating room, standard monitoring was applied, including electrocardiography, pulse oximetry, non-invasive blood pressure, and bispectral index (BIS). Patients were preoxygenated with 100% oxygen for 3 min. General anesthesia was induced with 1–2 mg/kg propofol and 1 µg/kg fentanyl. After loss of consciousness, 0.3 mg/kg rocuronium was administered intravenously, and the lungs were ventilated with a face mask. Adequate anesthetic depth for SAD insertion was confirmed by the absence of cardiovascular and motor responses to the jaw thrust maneuver.

The air-Q SP (Cookgas LLC, St. Louis, Missouri, USA) size was selected according to the manufacturer’s recommendations and patient body weight (Size 3, 30–60 kg; Size 4, 60–80 kg; Size 5, > 80 kg). All devices were lubricated with a water-soluble gel. Insertions were performed in a standardized fashion, following the manufacturer’s instructions, by the same two anesthesiologists (KZ, KG) who recruited the patients, both of whom were familiar with the device and had experience with at least 150 SAD insertions. Successful ventilation was defined as the presence of a square-wave capnographic trace, delivery of at least two consecutive tidal volumes, and the absence of audible air leak at a peak airway pressure ≤ 20 cmH₂O [10]. If two insertion attempts failed to achieve effective ventilation, the device placement was considered failed. If device failure was confirmed, the attending anesthesiologists were free to secure the airway with an alternative method. Following successful insertion, volume-controlled ventilation was initiated with a tidal volume of 8 mL/kg based on ideal body weight, a respiratory rate of 12–14 breaths/min, and a fresh gas flow of 3 L/min. Anesthesia was maintained with 1.5–2.0% sevoflurane in an O₂/air mixture to maintain BIS values between 40 and 60. Remifentanil was administered intravenously at a rate of 0.05–0.3 µg/kg/min.

OLP was measured one minute after successful air-Q SP placement and fixation, by closing the expiratory valve at 40 cmH₂O and setting the fresh gas flow at 3 L/min, followed by recording the airway pressure from the anesthesia monitor at the point when an audible leak was detected through the patient’s mouth [10, 11]. During the measurement, the patient was apneic and manually ventilated. The expiratory valve was set to 40 cm H₂O, thereby preventing the patient’s peak inspiratory pressure from exceeding 40 cm H₂O, it was assured that there was no ambient noise. During the measurements, patients were screened for increased inspiratory pressure, desaturation, bradycardia, arrhythmia, and hypotension. Gastric insufflation was defined as the presence of audible sounds over the epigastric area detected with a stethoscope during OLP measurement [10, 11]. SAD insertion time was defined as the interval from picking up the device until confirmation of the first capnographic waveform. Ease of insertion was assessed subjectively by the anesthesiologist performing the procedure, using a 4-point scale (1, no resistance; 2, mild resistance; 3, moderate resistance; 4, failure to insert) [12]. Maneuvers required to optimize device position, such as adjusting insertion depth, applying a jaw thrust, or performing head flexion/extension, were also recorded. PIP was recorded twice during the operation: first after successful SAD insertion and second before SAD removal. Fiberoptic scoring of the glottic view was performed (Insighters video flexible laryngoscope; Shenzhen Insighters Medical Technology Co. Ltd., Shenzhen, Guangdong, China) through the SAD, using the Brimacombe Score (1, vocal cords not visible; 2, vocal cords and anterior epiglottis visible; 3, vocal cords and posterior epiglottis visible; 4, vocal cords visible) [13]. Fiberoptic view was evaluated only once after the OLP and gastric insufflation measurements had been performed. All groups received the same intervention. Surgery was commenced after OLP, gastric insuflation, PIP and glottic view evaluations were completed. OLP, gastric insuflation, PIP, glottic view scoring measurements were done and recorded by one of the study reseachers (FSK) who was blinded to outcome parameters related to SAD insertion.

During surgery, a sudden increase in airway pressure, air leakage, increased PIP, hypoxia (peripheral oxygen saturation [SpO₂] < 90%), and displacement of the air-Q SP were recorded as SAD-event. Cases requiring reinsertion of the air-Q SP, replacement with another SAD, or conversion to tracheal intubation were documented, and these patients would be excluded from the study. Intravenous tramadol (1 mg/kg) and paracetamol (1 g) were given for postoperative analgesia 10 min prior to the completion of the procedure. At the conclusion of surgery, all anesthetic agents were discontinued, and residual neuromuscular blockade was reversed with 0.02 mg/kg neostigmine administered together with atropine. The air-Q SP was removed after adequate spontaneous respiration had returned and was inspected for the presence of blood.

During emergence from anesthesia, complications such as airway obstruction, breath-holding, coughing, hypoxia (SpO₂<90%), trauma, vomiting, and the presence of blood on the removed air-Q SP were recorded. Patiens were assed (KSF) for postoperative pharyngeal-laryngeal symptoms, including sore throat, dysphagia, and dysphonia, by interviewing them at first hour in the recovery unit and again at 24 h postoperatively in the ward.

A previous study [4] reported that the mean OLP was 18.4 ± 4.7 cm H₂O during classical LMA use in young and elderly adults. In our study, assuming that a 10–15% difference in OLP values between age groups in patients managed with the Air-Q SP would be considered clinically significant, the required sample size was calculated as 150 patients (50 per group), with an effect size (d) of 0.40, 80% power, and a type I error rate of 0.05. The study was completed with 51 patients in each group. The calculation was performed using the “G*Power 3.1.9.2” software.

For descriptive statistics of continuous variables, mean ± standard deviation, median, and interquartile range (25th–75th percentile) were presented, whereas categorical variables were expressed as percentages. The Shapiro–Wilk test was used to assess the normality of data distribution. For comparisons of continuous variables between age groups, one-way analysis of variance (ANOVA) was applied for normally distributed data, and post hoc Tukey test was used to determine the source of significant differences. For non-normally distributed continuous variables, the Kruskal–Wallis test was employed, followed by the Kruskal–Wallis multiple comparison test to identify group differences. The p values presented in the post hoc tests used for multiple comparisons were adjusted p values. For example, in the multiple comparison test performed following the Kruskal–Wallis variance analysis, the adjusted p values provided by the analysis were used. Adjusted p values (Adj. p value) were reported for differences between groups. The relationship between patients’ age and OLP values was analyzed using the Pearson correlation coefficient. Factors affecting the prediction of OLP values were evaluated using multivariate linear regression analysis. Chi-square or Fisher’s exact test was used for comparisons of categorical variables (cross-tabulations). IBM SPSS version 20 (Chicago, IL, USA) was used for all statistical analyses, and a p value of < 0.05 was considered statistically significant.

Results

One hundred and sixty-eight patients were initially assessed for eligibility, three of whom were excluded due to not meeting the inclusion criteria, 165 patients were divided into three groups according to age categories. In Group Young, three patients were excluded because the duration of surgery exceeded two hours, and one patient was excluded due to reoperation within 24 h. In Group Middle-aged, two patients were excluded because successful air-Q placement could not be achieved after two attempts, and two additional patients were excluded because the duration of surgery exceeded two hours. In Group Elderly, three patients were excluded because successful air-Q placement could not be achieved after two attempts, and one patient was excluded because a change in the surgical plan necessitated endotracheal intubation. The study was completed with 153 patients (Fig. 1).

Fig. 1.

STROBE flow diagram. Flow diagram summerizing patients enrolment. air- Q SP: Self-pressurising air-Q intubating laryngeal airway

Patient demographics and airway-related characteristics are presented in Table 1. In Group Young, 15 patients (29.4%) were female and 36 patients (70.6%) were male. In Group Middle-aged, 15 patients (29.4%) were female and 36 patients (70.6%) were male. In Group Elderly, 6 patients (11.8%) were female and 36 patients (88.2%) were male. No significant difference was observed in gender distribution among the groups (p = 0.053). Regarding height, patients in Group Young were found to be significantly taller than those in both Groups Middle-aged and Elderly (p = 0.001 and p = 0.008, respectively). The mean BMI of Group Middle-aged was significantly higher than that of Group Young (p = 0.016). ASA scores in Group Elderly were significantly higher compared with both Groups Young and Middle-aged (p < 0.001, p < 0.001). The ASA scores the Group Young, were found to be significantly lower compared with those of the other age groups (p = 0.000, p = 0.000) The prevalence of missing teeth was significantly greater in Group Elderly compared with Groups Young and Middle-aged (P < 0.001 and P = 0.002, respectively). The distribution of surgical procedures—including retrograde intrarenal surgery (RIRS), transurethral resection of bladder tumor (TURBT), transurethral resection of the prostate (TURP), ureterorenoscopy (URS), and other procedures such as internal urethrotomy and other cystoscopic procedures—is presented in Table 1.

Table 1.

Patient Demographics and Airway-Related Characteristics

Variable	Young group (n = 51)	Middle-aged group (n = 51)	Elderly group (n = 51)	P -value
Age (years), Mean ± SD	29.88 ± 6.81	53.08 ± 7.54	73.00 ± 6.07	< 0.001 c
Height (cm), Mean ± SD	173.53 ± 8.73	167.45 ± 8.71	168.57 ± 7.08	0.001 c *0.001 #0.008 £0.772
Weight (kg), Mean ± SD	80.94 ± 21.65	80.78 ± 13.41	75.47 ± 11.90	0.157 c
Body mass index (kg/m²), Mean ± SD	26.12 ± 5.38	28.72 ± 4.15	26.58 ± 4.42	0.013 c *0.016 #0.877 £0.057
Sex, n (%)
Female	15 [29.4]	15 [29.4]	6 [11.8]
Male	36 [70.6]	36 [70.6]	45 [88.2]	0.053 a
ASA classification, n (%)				< 0.001 a
I	26 (51.0)	5 (9.8)	0	*0.000
II	24 (47.1)	36 (70.6)	22 (43.1)	#0.000
III	1 (2.0)	10 (19.6)	29 (56.9)	£0.000
Mouth opening (cm), Median [IQR]	5 [5–6]	5 [4–5]	5 [4–5]	0.120 b
Mallampati score, n (%)
Class I	5 (9.8)	6 (11.8)	6 (11.8)	0.865 a
Class II	38 (74.5)	33 (64.7)	35 (68.6)
Class III	8 (15.7)	12 (23.5)	10 (19.6)
Air-Q size, n (%)
3	7 (13.7)	2 (3.9)	6 (13.7)	0,377 a
4	21 (41.2)	28 (54.9)	26 (51)
5	23 (45.1)	21 (41.2)	19 (37,3)
Surgery Tipe, n (%)
RIRS	23 (45.1)	34 (66.7)	10 (19.6)
TURBT	0	4 (7.8)	13 (25.5)
TURBT and URS	0	0	1 (2.0)
TUR-P	1 (2.0)	4 (7.8)	14 (27.5)
TUR-P and URS	0	1 (2.0)	0
URS	5 (9.8)	3 (5.9)	1 (2.0)
Other	22 (43.1)	5 (9.8)	12 (23.5)
Neck circumference (cm), Median [IQR]	40 [38–44]	42 [39–45]	41 [39–44]	0.386 b
Poor dentition, n (%)	2 (3.9)	7 (13.7)	21 (41.2)	< 0.001 a *0.160 #0.000 £0.002
Duration of anesthesia (min) Median [IQR]	65 [49–85]	58 [45–78]	61 [47–84]	0.652 b
Duration of surgery (min) Median [IQR]	53 [40–70]	50 [38–63]	55 [40–70]	0.821 b

Data are presented as mean (SD), median [IQR], number and percentage

ASA Anesthesiologists physical status, Poor dentition İncludes participants with missing, loose or broken teeth, RIRS Retrograde Intrarenal Surgery, TURBT Transurethral Resection of Bladder Tumor, TUR-P Transüretral Rezeksiyon Prostate, URS Üreterorenoskopi, Other Internal urethrotomy and other cystoscopic procedures, SD standart deviation, IQR interquartile range

a, Chi-Square Test; b, Kruskal-Wallis Analysis of Variance; c, ANOVA

*pairwise comparisons between age groups, addjusted p value between Groups Young and Middle-aged

# pairwise comparisons between age groups, adjusted p value between Groups Young and Elderly

£ pairwise comparisons between age groups, adjusted p value between the Groups Middle-aged and Elderly

The SAD insertion characteristics of the groups are presented in Table 2. The median [IQR] OLP values were 29 [26–35] cm H₂O in Group Young, 24 [14–39] cm H₂O in Group Middle-aged, and 26 [21–29] cm H₂O in Group Elderly. OLP values Group Young were significantly higher than those in both the middle-aged (p = 0.001) and elderly groups (p = 0.014) During OLP measurement, no complications such as inspiratory pressure exceeding 40 cmH₂O, desaturation, bradycardia, arrhythmia, or hypotension were observed in any patient. Regarding SAD insertion times, patients in Group Young had significantly shorter insertion times compared with both the Group Middle-aged (p = 0.001) and Group Elderly (p = 0.014). The need for additional maneuvers was significantly lower in Group Young than in Group Middle-aged and Group Elderly (p = 0.018 and p = 0.002, respectively). The proportion of patients with an ease-of-insertion grade I was significantly higher in Group Young compared with Group Middle-aged (p = 0.009) and Group Elderly (p = 0.034). In addition, the proportion of patients with a fiberoptic view grade 4 was significantly greater in Group Young compared with Group Elderly (P = 0.001). In all groups, PIP values measured before removal of the SAD were significantly higher than those measured after insertion (p < 0.001). PIP values. After SAD insertion in Group Young were significantly lower than those in both Group Middle-aged and Group Elderly (p = 0.006 and p = 0.043, respectively; p < 0.01). Additionally, before SAD removal PIP values in Group Young were significantly lower than in the Group Elderly (P = 0.032).

Table 2.

Comparison of Supraglottic Airway Devices Insertion Characteristics Among Groups

Variable	Group Young (n = 51)	Middle-aged group (n = 51)	Elderly group (n = 51)	p -value
OLP (cmH₂O), median [IQR]	29 [26–35]	24 [14–39]	26 [21–29]	0.001 b *0.001 #0.014 £1.000
PIP (mmHg) after SAD placement Median [IQR]	10 [9–13]	14 [10–17]	13 [10–16]	0.005b *0.006 #0.043 £0.032
PIP (mmHg) before SAD removal Median [IQR]	12 [10–17]	16 [12–18]	15 [12–18]	0.017b #0.032
	< 0.001c	< 0.001c	< 0.001c
Successful insertion time (sec), Median [IQR]	11 [10–13]	13 [11–16]	13 [11–15]	0.002 b *0.002 #0.032 £1.000
First-attempt success, n (%)
1	51 (100)	47 (92.2)	46 (90.2)	0.078 a
2	0	4 (7.8)	5 9.8
Insufflation, n (%)	6 (11.8)	8 (15.7)	10 (19.6)	0.553 a
Maneuver required, n (%)	2 (3.9)	10 (19.6)	13 (25.5)	0.010 a *0.018 #0.002 £0.477
Ease of insertion, n (%)
no resistance	33 (64.7)	21 (41.2)	22 (43.1)	0.031 a
mild resistance	16 (31.4)	22 (43.1)	23 (45.1)	*0.009
moderate resistance	2 (3,9)	8 (15.7)	6 (11.8)	#0.034
failure to insert	0	0	0	£0.847
Fiberoptic view, n (%)
Grade 1	1 (2.0)	5 (9.8)	6 (11.8)	0.009a
Grade 2	8 (15.7)	8 (15.7)	16 (31.4)	*0.017
Grade 3	1 (2.0)	5 (9.8)	6 (11.8)	#0.001
Grade 4	41 (80.4)	33 (64.7)	23 (45.1)	£0.201

Data are presented as mean, (SD), median [IQR], number and percentage

OLP Oropharyngeal leak pressure, PIP Peak Inspiratory Pressure, SAD Supraglottic airway devices, Grade 1 vocal cords not visible, Grade 2 vocal cords and anterior epiglottis visible, Grade 3 vocal cords and posterior epiglottis visible, Grade 4 vocal cords visible, SD standart deviation, IQR interquartile range

b, Kruskal-Wallis Analysis of Variance; a Chi-Square Test/Fisher’s Exact test; c, Wilcoxon tes.t

*pairwise comparisons between age groups, addjusted p value between Groups Young and Middle-aged

# pairwise comparisons between age groups, adjusted p value between Groups Young and Elderly

£ pairwise comparisons between age groups, adjusted p value between the Groups Middle-aged and Elderly

According to the results of the multivariate linear regression analysis including age, BMI, ASA status, and poor dentition variables for OLP values, BMI was identified as a significant explanatory factor for OLP (R² = 0.111, F = 4.639, p = 0.001). An one kg/m² increase in BMI was associated with a 0.335 cmH₂O increase in OLP values. Age, ASA status, and dentition variables were not found to be significant explanatory factors for OLP values (Table 3). Height was not included in the multivariate linear regression analysis because BMI is calculated using a formula that incorporates height; therefore, BMI and height were considered related variables, and height was excluded from the analysis. A significant negative correlation was found between patients’ age and OLP values (r = -0.239, p = 0.003). As patients’ age increased, OLP values decreased.

Table 3.

Factors Associated with Oropharyngeal Leak Pressure Values

Parameter	β	Std.Error	95% CI		p value
Constant	23.068	3.294	16.558	29.577	< 0.001
Age	-0.067	0.040	-0.145	0.012	0.096
BMI	0.335	0.116	0.105	0.564	0.005
ASA	-0.934	1.091	-3.090	1.223	0.394
Poor dentition	-0.684	1.492	-3.632	2.264	0.647

p value obtained using the Multivariate Linear Regression Analysis

ASA Anesthesiologists physical status, Std.Error Standard error, CI Confidence Interval, Poor dentition: includes participants with missing, loose, or broken teeth

The intraoperative and postoperative complications of the groups are presented in Table 4. During the operation, the incidence of SAD events (including air leakage, increased PIP, and device displacement) was significantly higher in Group Elderly compared with Group Young (P = 0.006). No patient experienced oxygen desaturation during the operation due to SAD-event such as SAD displacement, increased PIP or air leakage. No patient required air-Q SP reinsertion, replacement with another SAD, or conversion to endotracheal intubation due to intraoperative SAD event. At postoperative first hour, the incidence of dysphagia was significantly higher in Group Young compared with Group Elderly (P = 0.014). Additionally, the incidence of dysphonia at postoperative first hour was significantly higher in Group Young compared with both Group Middle-aged and Group Elderly (p = 0.041 and p = 0.041, respectively).

Table 4.

Comparison of Intraoperative and Postoperative Complications Among the Groups

Variable	Young group (n = 51)	Middle-aged group (n = 51)	Elderly group (n = 51)	p-value
SAD event, n (%)	0	4 (7.8)	8 (15.7)	< 0.010a *0.118 #0.006 #0.219
Emerge
Hypoxia, n (%)	5 (9.8)	3 (5.9)	5 (9.8)	0.816 a
Cough, n (%)	6 (11.8)	3 (5.9)	5 (9.8)	0.686 a
Breath-holding, n (%)	9 (17.6)	2 (3.9)	3 (5.9)	0.063 a
Trauma, n (%)	0	1 (2.0)	0	1.000 a
Bleeding, n (%)	0	1 (2.0)	1 (2.0)	1.000 a
Vomiting, n (%)	1 (2.0)	0	0	1.000 a
Postoperative firsth hour
Sore throat, n (%)	14 (27.5)	13 (25.5)	7 (13.7)	0.197 a
Dysphagia, n (%)	10 (19.6)	6 (11.8)	2 (3.9)	0.049 a *0.276 #0.014 #0.269
Dysphonia, n (%)	4 (7.8)	0	0	0.034 a *0.041 #0.041 £1.000
Postoperative 24 h
Sore throat, n (%)	6 (11.8)	8 (15.7)	3 (5.9)	0.284 a
Dysphagia, n (%)	7 (13.7)	4 (7.8)	3 (5.9)	0.465 a
Dysphonia, n (%)	1 (2.0)	0	0	1.000 a

Data are presented as number and percentage

SAD event SAD displacement, increased peak inspiratory pressure, or air leakage

a: Chi-Square Test/Fisher’s Exact test

* When the differences were further examined using pairwise comparisons between age groups, the p value between the young and middle-aged groups

# When the differences were further examined using pairwise comparisons between age groups, the p value between the young and elderly groups

£ When the differences were further examined using pairwise comparisons between age groups, the p value between the middle-aged and elderly groups

Discussion

In the present study, the performance of the air-Q self-pressurizing intubating laryngeal airway, a cuffless supraglottic airway device, was compared among three different age groups: young, middle-aged, and elderly adults. In Group Young, compared with Group Middle-aged and Group Elderly the air-Q SP provided higher oropharyngeal leak pressures, allowed faster and easier insertion, required fewer insertion maneuvers, yielded better fiberoptic views, and was associated with lower PIP after air-Q SP placement However, the rates of dysphonia and dysphagia at postoperative firsth hour were significantly higher in Group Young compared with the other groups.

OLP is defined as the airway pressure at which leakage occurs around the device and is used to evaluate the sealing function of supraglottic airway devices [14, 15]. Recently, it has been reported that SADs, by providing higher OLP and lower PIP, can ensure safer anesthesia and adequate ventilation in settings that require high airway pressures, such as laparotomy, laparoscopy, and in obese patients [16–18]. In our study, after air-Q SP placement PIP values were found to be lower in Group Young, and before removal air-Q SP PIP values were also lower compared to other groups. Therefore, due to the higher OLP and lower PIP values observed in Group Young, the air-Q SP appears to provide superior sealing function in young patients compared with the middle-aged and elderly.

Previous studies have reported that age-related structural changes occur in the pharyngeal airway. The volume and/or cross-sectional area of the pharyngeal airway may be greater in elderly individuals compared with younger subjects [2, 19, 20]. In addition, pharyngeal airway length has been shown to increase with age [2, 21]. These anatomical alterations may modify the potential space in which the air-Q SP is positioned. Furthermore, the resting pressure of the upper esophageal sphincter (UES) has been reported to be lower in elderly individuals, and the length of the UES high-pressure zone is shorter compared with younger subjects [3]. This may influence the depth of insertion of the air-Q SP into the UES.

Age-related differences in SAD performance were investigated with limited number of previous studies. Kim et al. compared the effectiveness of the classic LMA, between young and elderly patients, without including a middle-aged group. In line with our hypothesis, the first-attempt successful ventilation rate was higher in younger patients, whereas the number of manipulations and insertion time were longer in elderly patients; however, the OLP was found to be similar between the groups [4]. In a study comparing the i-gel and air-Q SP in elderly patients, the i-gel provided a better airway seal than the air-Q SP, whereas the air-Q SP was associated with improved fiberoptic visualization. No significant differences were observed between the two groups in terms of SAD insertion characteristics or complications. Furthermore, in that study evaluating the i-gel and air-Q SP in elderly patients, the first-attempt success rate was lower than that observed in our study, while the proportion of patients requiring no additional maneuvers was similar, 66.7% and 14.6% respectively [9]. In another study conducted in non-elderly adult patients, the ProSeal LMA demonstrated a higher OLP than the air-Q SP; however, the air-Q SP was associated with a shorter mean insertion time and superior fiberoptic grading of the laryngeal view. Additionally, no significant differences were found between the two devices regarding ease of insertion or maneuver requirements [22].

Despite studies comparing the air-Q SP with other SADs in terms of patient age, the device was not compared in diverse age groups previously. The distribution of OLP values in Group Young Middle-aged, and Elderly in our study (29 [26–35], 24 [14–39], and 26 [21–29] cmH₂O, respectively) were considered sufficient for adequate ventilation during routine anesthesia [7, 23, 24].

Ease of SAD insertion can be evaluated with, the need for manipulations during placement, first-attempt success and the insertion time of the SAD. Shortening the insertion time was important because geriatric patients are highly vulnerable to respiratory and/or neurological morbidity and mortality due to reduced functional reserve of the respiratory system and delayed ventilatory responses to oxygen desaturation or carbon dioxide (CO₂) retention [25]. Nevertheless, oxygen saturation levels did not fall below 90% in any patient. Given the anatomical and physiological characteristics of elderly patients, airway management may be delayed in cases of difficult intubation, rendering elderly patients more susceptible to perioperative hypoxemia compared with younger patients. This susceptibility may be further increased by the use of neuromuscular blocking agents.

As for the fiberoptic glottic views, notably, in pediatric cases, the air-Q has been reported to provide superior fiberoptic views compared to other supraglottic airway devices [26]. Previous studies have shown that comparing the air-Q and the Fastrach LMA, the blind tracheal intubation success rate was 77% in the air-Q group; however, the Fastrach LMA was found to be superior for blind intubation [27]. In our study, Group Young patients demonstrated better fiberoptic view grades compared with Group Elderly patients, suggesting that the air-Q SP may offer an advantage as an intubation conduit in younger populations. Nevertheless, further studies are warranted to clarify this potential benefit.

No significant differences were observed among age groups in the rate of complications during emergence from anesthesia, including hypoxia, cough, breath-holding, trauma, bleeding, and vomiting. Previous studies showed that postoperative complications related to LMA and endotracheal tube use are associated with device size and cuff pressure, with LMA Supreme showing the lowest complication rates [28]. High LMA cuff pressure may reduce mucosal perfusion and increase injury risk [29]. MRI findings demonstrated anatomical differences between devices, with LMA-S positioned deeper than i-gel™ despite similar clinical findings [30]. The air-Q SP avoids cuff hyperinflation due to its non-inflatable design, but complications may still occur [7]. Patient age and airway anatomy, by influencing device sealing, may affect outcomes by altering oropharyngeal pressure even with the same device size. Further studies comparing supraglottic airway devices in younger and older populations are needed to assess their effects on dysphagia and dysphonia.

According to our protocol, we prefer the use of neuromuscular blocking agents before SAD insertion in elderly patients [31], avoidance of excessive head and neck extension to achieve better sealing and ventilation [15], selection of second-generation SADs for improved sealing and protection against aspiration [32] and the use of cuffless SADs, which may allow faster insertion and shorter apneic duration while avoiding cuff hyperinflation–related postoperative complications [7], as these approaches may provide clinical advantages in this population.

To further discuss the effect of sex on our results oropharyngeal airway length increases with age in both sexes and correlates with height only in women. Men have larger oropharyngeal length and volume. In men, aging decreases upper and increases lower soft tissue volume, while no age-related changes are seen in women [21]. Our study is original in demonstrating a negative correlation between age and OLP values as age increased, the clinical performance of the device decreased. The oropharynx and hypopharynx become more spherical with increasing BMI due to a reduced transverse diameter [20]. According to our results although BMI was associated with OLP, in the middle-aged group showed lower OLP despite having higher BMI. It is worth mentioning that evaluating the airway structure with radiological imaging with computed tomography or magnetic resonans imaging or airway ultrasonund would have been more conclusive in this regard.

One of the strengnts of the presenting study is that, by nature of the group allocation according to age, the anesthesiologist performing SAD insertion could not be blinded, therefore we choose to assess the SAD performance outcome measures as well as complications with a single blind methodology to avoid awareness about the insertion process wich could have subconsciously influenced the evaluation, thereby overestimating the true comparative effect between groups. Poor dentition in elderly patients may affect air-Q SP performance. Previous studies with LMA Unique™ showed higher first-attempt insertion success in dentate patients, although oropharyngeal leak pressure was similar between dentate and edentulous groups [33]. Therfore we excluded edentelous patients considering that edentulism may occur at a higher rate in the elderly which might have caused for bias. We also excluded patients with a BMI ≥ 40 kg/m² because in obese patients, increased fat and hypopharyngeal tissue may lead to tighter device placement [34, 35] and might have effected our outcomes. However this methodology prevents the generalizability of our results to this patient population. Another limitation is that we were not be able to include patients from diverse etnicities, which may hinder the generalizability of our results. Also our results may not apply to conditions where neuromuscular blocker are not used before SAD placement. Given the varying advantages of different SADs in elderly patients, clinicians managing geriatric patients should select the SAD most appropriate for the individual patient’s clinical requirements. In this regard we suggest that our results make a contribution to the literautre.

In conclusion, in young patients undergoing general anesthesia with a neuromuscular blocking agent, the air-Q SP provided better sealing function, superior fiberoptic visualization, easier and faster insertion, required, fewer placement maneuvers and intraoperative SAD-related complications were lower compared with Groups Middle-aged and Elderly however, transient early postoperative dysphagia and dysphonia were more frequent in Group. Young Nevertheless, the air-Q SP was sufficient for adequate ventilation during routine anesthesia in all groups.

Abbreviations

SAD

Supraglottic airway devices

air-Q SP

Self-pressurising air-Q intubating laryngeal airway

OLP

Oropharyngeal leak pressure

ASA

American Society of Anesthesiologists

PIP

Peak inspiratory pressure

BIS

Bispectral index

spO2

Peripheral oxygen saturation

IQR

Interquartile range

BMI

Body Mass Index

CO₂

Carbon dioxid

Authors’ contributions

Z.K.: Conceptualisation, Methodology, Supervision, Writing – original draft. G.K.: Data curation, Formal analysis, Investigation. S.F.K.: Data curation, Investigation. C.K.C.: Investigation, Resources. S.A.: Methodology, Software, Formal analysis, Writing – review & editing. J.E.: Visualisation, Validation, Writing – review & editing. All authors reviewed and approved the final manuscript.

Funding

This study was not funded.

Data availability

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

This prospective comparative study was approved by the Ethics Committee of Ankara Etlik City Hospital (AEŞH-BADEK-2024-490). Written informed consent was obtained from all patients. All procedures performed in studies involving human participant wew accordance with the ethical standarts of the institutional and/or national research commitee and with the 1964 Helsinki declaration (as revised in 2013) and its later amendments or comparable ethical standarts.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.