Manali Gupta1, Shikha Soni2, Deepak Chaudhary3, Chanda Khatri4, Rakesh Karnawat5
Author affiliation:
Background: Airtraq®-Airview (AA) and King Vision® (KV) video laryngoscopes are two new video laryngoscopes (VLS). Many studies have been carried out to compare the both regarding efficacy, ease of use etc., but the matter remains undecided.
We compared AA to KV(channeled) primarily for total intubation time and secondarily for success rate, number of attempts, optimization maneuvers, percentage of glottis opening (POGO) score, Cormack-Lehane (CL) score, degree of difficulty of intubation (Likert scale) and adverse effects.
Methodology: After obtaining institutional ethical committee approval and written informed consent from study subjects, this randomized control study was conducted in the Department of Anesthesiology & Critical Care, Mathura Das Mathur Hospital, Jodhpur from January 2019 to September 2019. Seventy ASA- I and II patients of age 20-60 y, weighing 40-70 kg, irrespective of their Mallampati class, posted for elective surgery under general anesthesia, were included in the study. Patients were randomly divided into two groups, Group AA (n = 35) intubated using AA and Group KC (n = 35) intubated using KV (channeled). Pregnant patients, patients with mouth opening less than 18 mm and any oral pathology, neck deformities and refusal to consent were excluded. Statistical analyses were performed using SPSS 22.0 software package (SPSS Inc., Chicago, IL, USA). Chi square test, Fisher’s exact test and Fisher-Freeman-Halton test were used. All data were summarized as mean ± SD for continuous variables, numbers and percentages for categorical variables. P < 0.05 was accepted as significant.
Results: Total intubation time was significantly longer in group AA. Demographic and hemodynamic data of patients and intubation attempts, CL score, POGO score, degree of difficult intubation on Likert scale and adverse effects such as airway trauma in both the groups were comparable.
Conclusions: Although both video laryngoscopes are similar in intubating conditions, intubation with King’s Vision® video laryngoscope was faster; hence might be preferable for intubation.
Key words: Airway management; glottis; Humans; Intubation, Intratracheal / instrumentation; Intubation, Intratracheal / methods; Laryngoscopy / instrumentation; Laryngoscopy / methods; Trachea; Video laryngoscopy
Citation: Gupta M, Soni S, haudhary D, Khatri C, Karnawat R. Airtraq-AirView® vs King Vision® video laryngoscope: A randomized comparative study to evaluate the intubation dynamics in adult patients for general anesthesia. Anaesth. pain intensive care 2022;26(4):433-438; DOI: 10.35975/apic.v26i4.1944
Received: March 14, 2022; Reviewed: April 13, 2022; Accepted: July 10, 2022
Video laryngoscopy(VLS) is one of the most significant development in airway management and VLSs are now included in the American Society of Anesthesiologists (ASA) Difficult Airway Algorithm.1 The Airtraq® Airview (AA)(ProdolMeditec, S.A., Vizcaya, Spain) is a single-use channeled video laryngoscope (VLS) for endotracheal intubation, that projects images of glottis from the distal tip of its blade to a proximal eyepiece. Alternatively any mobile phone may be attached to its handle and used with Airview app (iPhone-app by MobilemedS`arl, Switzerland) for visualization.2,3 King Vision® (KV) VLS (King Systems Noblesville, IN, USA) consists of two parts, a reusable monitor, and a disposable blade which may be ‘channeled’ (conduit for the endotracheal tube) or ‘non-channeled’.4 Several studies have reported that both AA and KV allowed faster learning curve, better glottis visualization and Cormack Lehane (CL) score than that of obtained by direct laryngoscopy.5,6,7,8 They both offer a blade that incorporates a tube channel that holds the endotracheal tube (ETT) and guides it towards the glottis with visualization on display monitor.9 There are various studies comparing direct laryngoscopy and newer intubating devices but very few studies have been conducted comparing efficacy of intubation among different VLSs.10,11,12
We compared the intubation efficacy and dynamics of AA with KV (channeled). The primary objective was to compare total intubation time among the two devices. Secondary objectives included comparison of success rate, total number of attempts, need of optimization maneuvers (external laryngeal manipulation), percentage of glottis opening (POGO score), CL score, degree of difficulty of intubation (Likert scale) and adverse effects.
Sample size was calculated on the basis of a previous study by Ali et al.13 Minimum of 35 patients were required in each group to study the difference between tracheal intubation time in both the techniques, at a power of 80% and confidence interval of 95%. We enrolled 35 patients in each group in accordance with central limit theorem (assuming α-error = 0.05 and β-error = 0.2 or power = (1-β) = 0.8). All data were summarized as mean ± standard deviation (SD) for continuous variables, numbers and percentages for categorical variables. P < 0.05 was accepted as statistically significant.
This randomized control study was conducted in the Department of Anesthesiology & Critical Care, Mathura Das Mathur Hospital, Jodhpur from January 2019 to September 2019 after obtaining institutional ethical committee approval and written informed consent from the study subjects.
A total of seventy patients, ASA-I and II, posted for elective surgery under general anesthesia with were included. Patients in the age group 20-60 y, weighing 40-70 kg, irrespective of their Mallampati grades, were enrolled, while pregnant patients, patients with mouth opening less than 18 mm and patients with any oral pathology, neck flexion deformities and non-consenting patients were excluded. The subjects were divided into two groups, Group-AA (n = 35) was intubated using AA and Group-KC (n = 35) was intubated using KV(channeled).
After arrival of the patient in operation theatre, baseline reading of heart rate (HR), electrocardiography (ECG), pulse oximetry (SpO2) and non-invasive blood pressure (NIBP) were recorded. Intravenous line was secured and patients were premedicated with midazolam 0.05 mg/kg IV, lignocaine 1 mg/kg IV and glycopyrrolate 0.005 mg/kg IV. After pre-oxygenation, anesthesia was induced with fentanyl 2 µg/kg and propofol 2–3 mg/kg IV. After confirmation of adequate bag-mask ventilation, vecuronium 0.1 mg/kg was used for neuromuscular blockade. Bag and mask ventilation was done for 3 min.
The group allocation was done using the numerical order of a computer‑generated randomization list. Allocation concealment was ensured with sealed envelopes. All intubations were performed using either Airtraq-Airview® (Group AA) or KV (channeled) (Group KC), according to the group allocated. One experienced anesthesiologist intubated and another one recorded the time taken for intubation with a stopwatch. Minimum 25 insertions with AA and KV each were done by the intubating anesthesiologist before starting the study. Endotracheal tube (ETT) size 7.0 mm internal diameter (ID) was used for female and 7.5 mm ID for male patients. The selected ETT was lubricated with lignocaine jelly and preloaded into the guide channel of the allocated device. patient's head was keeping in the neutral position and the laryngoscope was inserted in the midline from center of the tongue towards vallecula. ETT was advanced into the trachea with continue monitoring of glottis view in the monitor. the laryngoscope was separated from the ETT and removed from the mouth after intubation. ETT was connected to mechanical ventilator and carbon dioxide sample line. Three intubation attempts were allowed and in case of failed intubation, classic laryngeal mask airway would be used and the patient excluded from the study. Airway trauma was assumed if the blade was stained with blood. Anesthesia was maintained by vecuronium and sevoflurane, and reversed by neostigmine-glycopyrrolate. Total intubation time was defined as the time when the blade tip passed the incisors to the point until confirmation of the first wave of carbon dioxide on the capnometer. Intubation was termed as failed if total intubation time exceeded 120 sec, or three intubation attempts failed. POGO score was the percentage of glottic opening seen, defined by the linear span from the anterior commissure to the inter-arytenoid notch, ranging from 100% when entire glottic aperture was visualized, to 0% when no glottic structure could be visualized.14 On the basis of views of the structures seen on laryngoscopy, CL grade was Grade-1, when a full view of glottis was visible; Grade-2, if only the posterior extremity of the glottis was visible; Grade-3, if no glottis was visible, but epiglottis was seen; and Grade-4, if neither glottis nor epiglottis could be seen.15
Five-point Likert scale was used to rate the degree of difficulty of intubation ranging from one to five; very easy = 1, followed by easy = 2, neutral = 3, difficult = 4 and very difficult = 5.16 Need for external laryngeal manipulations like BURP maneuver (backwards, upwards and rightwards pressure) to improve glottis view if required was noted as an optimization maneuver.17 Adverse effects such as airway trauma, esophageal intubation, bronchospasm and throat pain were also noted.
Statistical analysis
All statistical analyses were performed by using SPSS (Statistical package for the social sciences) 22.0 software package (SPSS Inc., Chicago, IL, USA). Yates continuity correction test (Chi square test), Fisher’s exact test and Fisher---Freeman---Halton test were used for comparison of qualitative data.
Out of 96 patients who were evaluated for eligibility, 70 patients were analyzed in the study (Figure 1). All the patients were statistically comparable regarding demographic parameters, e.g., age, weight, sex, MPG, ASA (Table 1 and 2) (P > 0.05); and hemodynamic parameters, e.g., HR, NIBP, and SpO2, in pre-induction, postinduction and post-intubation periods (P > 0.05). However, total intubation time was longer in Group-AA (23.34 ± 3.98 sec) than Group-KV (20.42 ± 2.90 sec). There was statistically significant difference in total intubation time (P = 0.0008) (Table 3). All the intubation attempts in both the groups were successful. Total number of laryngoscope insertion attempts were less in Group-KV than Group-AA but the difference was statistically not significant (P = 0.460). Need for optimization maneuver such as external laryngeal manipulation was more in Group-AA (three patients) as compared to Group-KV (two patients) but difference was statistically not significant (P = 1.000). The CL score and mean POGO score were better in Group-KV than Group-AA but the difference was not significant statistically (P > 0.05). Thirty patients of Group-AA and thirty-two patients of Group-KV had CL grade-I, whereas five patients in Group-AA and only three patients of Group-KV had grade-IIa. The mean POGO score was also high in Group-KV (97.42 ± 6.10) as compared to Group-AA (95.71 ± 1.92), the difference was statistically significant (P = 0.420). Degree of difficult intubation (Likert scale) was found more in Group-AA than Group-KV however, there was no statistically significant difference (P = 0.861). The difference in the incidence of adverse effects such as airway trauma was statistically insignificant between the groups (P = 1.000). Other adverse effects such as esophageal intubation, bronchospasm and throat pain were not observed in any of the patient in both of the groups (Table 3).
Very limited studies have been conducted on patients comparing AA and KV. In our study we compared the intubation efficacy of AA with that of KV(Channeled) on adult patients undergoing elective surgeries under general anesthesia. Our main aim was to compare total intubation time (in sec). We also assessed success rate, number of attempts, need of optimization maneuvers, POGO-score, CL-score, degree of difficulty of intubation (Likert scale) and adverse effects. In our study, the mean total intubation time for Group-AA was more than Group-KV and was statistically significant. In a similar study comparing Airtraq (but without Airview) with KV, the results were similar.13 The time to secure airway was significantly longer when using Airtraq (38 ± 18 sec) compared to KV (26 ± 11 sec). However, Airview feature was not used in the study and the anesthetist had to look through an eyepiece to visualize the glottis in Airtraq group. This might explain prolongation of mean intubation time in that study in group-A (Airtraq), when compared to intubation time by Airtraq-Airview in our study. In a study done on mannequins comparing intubating conditions and ease of intubation between AA and KV, the results were contrasting to our study.18 They observed that the time necessary to identify glottis to insert the tube and inflate its cuff, and to ventilate the lungs was significantly shorter with the Group-AA than Group-KVC. The difference in the result of the above study may be explained by the fact that their study was done on mannequins who do not replicate normal human anatomy completely. Our study had 100% success rate in both the groups while in a similar study all intubations performed with King Vision group were successful and only one intubation performed with Airtraq group was not successful (P > 0.05).13 The CL-view and POGO score obtained were reported better with the Group-KV in our study, however no significant difference was found between the two groups (P > 0.05). Another study which included paramedics and compared Airtraq with KV in a tactical setting, CL views between different VLSs were comparable; although they used the Airtraq with its eyepiece, external viewing of the intubation process was not possible.19 Another study on mannequins, the pre-intubation CL was statistically better with KV although during intubation, CL were similar in the two groups.18 In our study successful single attempt intubations were more in Group-KV, and Group-AA had higher number of second and third attempts, but the difference was statistically insignificant (P > 0.05). The number of attempts was statistically lower with KV when it was compared to Airtraq without Airview.17 VLS facilitates easy visualization of the glottis without a direct line of sight reducing the need of optimizing maneuvers. Optimization maneuver requirement was less in Group-KV. Many authors have documented reduced need of optimization maneuvers in VLS groups compared to conventional laryngoscope group.7,20 Although one study did not report any difference in Likert scale,18 our study found higher difficulty in Group-AA although statistically the difference was insignificant, which might be explained by the fact that KV had the better indirect laryngoscopic view than AA. Some authors reported more airway trauma more in Airtraq group, which was not significant as reported in our study.17
Considering the results of statistical analysis of our study, it can be concluded that both Airtraq® Airview and King Vision® provide satisfactory intubation conditions, but use of King Vision® might be preferable for endotracheal intubation in adult patients undergoing elective surgery as it has shorter total intubation time, other parameters being similar to Airtraq® Airview.
6. Limitations of the study
Single user approach is the strength of the study as it reduces inter-individual skill differences and reduces bias.
8. Data availability
The numerical data generated during this research is available with the authors.
9. Conflict of interest
No external or industry funding was involved in the study.
10. Authors’ contribution
MG: Concept and design of the study, acquisition, analysis and interpretation of data, drafting the paper, Final approval of the version
SS: Concept, revising the manuscript for intellectual content, final approval
DC: Interpretation of data, manuscript editing, final approval
CK: Analysis and interpretation of data, manuscript editing, final approval of the version
RK: Concept and design, revising it critically for intellectual content, final approval
Author affiliation:
- Manali Gupta, Ex-Resident, Dr. S. N. Medical College, Jodhpur, Rajasthan, India; E-mail- manalig123@gmail.com
- Shikha Soni, Associate Professor, Dr. S. N. Medical College, Jodhpur, Rajasthan, India; E-mail- shikhasoni.19@gmail.com
- Deepak Chaudhary, Assistant Professor, PDU Medical College, Churu, Rajasthan, India; E-mail- drdeepak.rj19@gmail.com
- Chanda Khatri, Associate Professor, Dr. S. N. Medical College, Jodhpur, Rajasthan, India; E-mail- chandakhatri90@gmail.com
- Dr. Rakesh Karnawat, Senior Professor, Dr. S. N. Medical College, Jodhpur, Rajasthan, India; E-mail- dr.rakeshkarnawat@yahoo.com
Abstract
Background: Airtraq®-Airview (AA) and King Vision® (KV) video laryngoscopes are two new video laryngoscopes (VLS). Many studies have been carried out to compare the both regarding efficacy, ease of use etc., but the matter remains undecided.
We compared AA to KV(channeled) primarily for total intubation time and secondarily for success rate, number of attempts, optimization maneuvers, percentage of glottis opening (POGO) score, Cormack-Lehane (CL) score, degree of difficulty of intubation (Likert scale) and adverse effects.
Methodology: After obtaining institutional ethical committee approval and written informed consent from study subjects, this randomized control study was conducted in the Department of Anesthesiology & Critical Care, Mathura Das Mathur Hospital, Jodhpur from January 2019 to September 2019. Seventy ASA- I and II patients of age 20-60 y, weighing 40-70 kg, irrespective of their Mallampati class, posted for elective surgery under general anesthesia, were included in the study. Patients were randomly divided into two groups, Group AA (n = 35) intubated using AA and Group KC (n = 35) intubated using KV (channeled). Pregnant patients, patients with mouth opening less than 18 mm and any oral pathology, neck deformities and refusal to consent were excluded. Statistical analyses were performed using SPSS 22.0 software package (SPSS Inc., Chicago, IL, USA). Chi square test, Fisher’s exact test and Fisher-Freeman-Halton test were used. All data were summarized as mean ± SD for continuous variables, numbers and percentages for categorical variables. P < 0.05 was accepted as significant.
Results: Total intubation time was significantly longer in group AA. Demographic and hemodynamic data of patients and intubation attempts, CL score, POGO score, degree of difficult intubation on Likert scale and adverse effects such as airway trauma in both the groups were comparable.
Conclusions: Although both video laryngoscopes are similar in intubating conditions, intubation with King’s Vision® video laryngoscope was faster; hence might be preferable for intubation.
Key words: Airway management; glottis; Humans; Intubation, Intratracheal / instrumentation; Intubation, Intratracheal / methods; Laryngoscopy / instrumentation; Laryngoscopy / methods; Trachea; Video laryngoscopy
Citation: Gupta M, Soni S, haudhary D, Khatri C, Karnawat R. Airtraq-AirView® vs King Vision® video laryngoscope: A randomized comparative study to evaluate the intubation dynamics in adult patients for general anesthesia. Anaesth. pain intensive care 2022;26(4):433-438; DOI: 10.35975/apic.v26i4.1944
Received: March 14, 2022; Reviewed: April 13, 2022; Accepted: July 10, 2022
1. Introduction
Video laryngoscopy(VLS) is one of the most significant development in airway management and VLSs are now included in the American Society of Anesthesiologists (ASA) Difficult Airway Algorithm.1 The Airtraq® Airview (AA)(ProdolMeditec, S.A., Vizcaya, Spain) is a single-use channeled video laryngoscope (VLS) for endotracheal intubation, that projects images of glottis from the distal tip of its blade to a proximal eyepiece. Alternatively any mobile phone may be attached to its handle and used with Airview app (iPhone-app by MobilemedS`arl, Switzerland) for visualization.2,3 King Vision® (KV) VLS (King Systems Noblesville, IN, USA) consists of two parts, a reusable monitor, and a disposable blade which may be ‘channeled’ (conduit for the endotracheal tube) or ‘non-channeled’.4 Several studies have reported that both AA and KV allowed faster learning curve, better glottis visualization and Cormack Lehane (CL) score than that of obtained by direct laryngoscopy.5,6,7,8 They both offer a blade that incorporates a tube channel that holds the endotracheal tube (ETT) and guides it towards the glottis with visualization on display monitor.9 There are various studies comparing direct laryngoscopy and newer intubating devices but very few studies have been conducted comparing efficacy of intubation among different VLSs.10,11,12
We compared the intubation efficacy and dynamics of AA with KV (channeled). The primary objective was to compare total intubation time among the two devices. Secondary objectives included comparison of success rate, total number of attempts, need of optimization maneuvers (external laryngeal manipulation), percentage of glottis opening (POGO score), CL score, degree of difficulty of intubation (Likert scale) and adverse effects.
2. Methodology
Sample size was calculated on the basis of a previous study by Ali et al.13 Minimum of 35 patients were required in each group to study the difference between tracheal intubation time in both the techniques, at a power of 80% and confidence interval of 95%. We enrolled 35 patients in each group in accordance with central limit theorem (assuming α-error = 0.05 and β-error = 0.2 or power = (1-β) = 0.8). All data were summarized as mean ± standard deviation (SD) for continuous variables, numbers and percentages for categorical variables. P < 0.05 was accepted as statistically significant.
This randomized control study was conducted in the Department of Anesthesiology & Critical Care, Mathura Das Mathur Hospital, Jodhpur from January 2019 to September 2019 after obtaining institutional ethical committee approval and written informed consent from the study subjects.
A total of seventy patients, ASA-I and II, posted for elective surgery under general anesthesia with were included. Patients in the age group 20-60 y, weighing 40-70 kg, irrespective of their Mallampati grades, were enrolled, while pregnant patients, patients with mouth opening less than 18 mm and patients with any oral pathology, neck flexion deformities and non-consenting patients were excluded. The subjects were divided into two groups, Group-AA (n = 35) was intubated using AA and Group-KC (n = 35) was intubated using KV(channeled).
After arrival of the patient in operation theatre, baseline reading of heart rate (HR), electrocardiography (ECG), pulse oximetry (SpO2) and non-invasive blood pressure (NIBP) were recorded. Intravenous line was secured and patients were premedicated with midazolam 0.05 mg/kg IV, lignocaine 1 mg/kg IV and glycopyrrolate 0.005 mg/kg IV. After pre-oxygenation, anesthesia was induced with fentanyl 2 µg/kg and propofol 2–3 mg/kg IV. After confirmation of adequate bag-mask ventilation, vecuronium 0.1 mg/kg was used for neuromuscular blockade. Bag and mask ventilation was done for 3 min.
The group allocation was done using the numerical order of a computer‑generated randomization list. Allocation concealment was ensured with sealed envelopes. All intubations were performed using either Airtraq-Airview® (Group AA) or KV (channeled) (Group KC), according to the group allocated. One experienced anesthesiologist intubated and another one recorded the time taken for intubation with a stopwatch. Minimum 25 insertions with AA and KV each were done by the intubating anesthesiologist before starting the study. Endotracheal tube (ETT) size 7.0 mm internal diameter (ID) was used for female and 7.5 mm ID for male patients. The selected ETT was lubricated with lignocaine jelly and preloaded into the guide channel of the allocated device. patient's head was keeping in the neutral position and the laryngoscope was inserted in the midline from center of the tongue towards vallecula. ETT was advanced into the trachea with continue monitoring of glottis view in the monitor. the laryngoscope was separated from the ETT and removed from the mouth after intubation. ETT was connected to mechanical ventilator and carbon dioxide sample line. Three intubation attempts were allowed and in case of failed intubation, classic laryngeal mask airway would be used and the patient excluded from the study. Airway trauma was assumed if the blade was stained with blood. Anesthesia was maintained by vecuronium and sevoflurane, and reversed by neostigmine-glycopyrrolate. Total intubation time was defined as the time when the blade tip passed the incisors to the point until confirmation of the first wave of carbon dioxide on the capnometer. Intubation was termed as failed if total intubation time exceeded 120 sec, or three intubation attempts failed. POGO score was the percentage of glottic opening seen, defined by the linear span from the anterior commissure to the inter-arytenoid notch, ranging from 100% when entire glottic aperture was visualized, to 0% when no glottic structure could be visualized.14 On the basis of views of the structures seen on laryngoscopy, CL grade was Grade-1, when a full view of glottis was visible; Grade-2, if only the posterior extremity of the glottis was visible; Grade-3, if no glottis was visible, but epiglottis was seen; and Grade-4, if neither glottis nor epiglottis could be seen.15
Five-point Likert scale was used to rate the degree of difficulty of intubation ranging from one to five; very easy = 1, followed by easy = 2, neutral = 3, difficult = 4 and very difficult = 5.16 Need for external laryngeal manipulations like BURP maneuver (backwards, upwards and rightwards pressure) to improve glottis view if required was noted as an optimization maneuver.17 Adverse effects such as airway trauma, esophageal intubation, bronchospasm and throat pain were also noted.
Statistical analysis
All statistical analyses were performed by using SPSS (Statistical package for the social sciences) 22.0 software package (SPSS Inc., Chicago, IL, USA). Yates continuity correction test (Chi square test), Fisher’s exact test and Fisher---Freeman---Halton test were used for comparison of qualitative data.
3. Results
Out of 96 patients who were evaluated for eligibility, 70 patients were analyzed in the study (Figure 1). All the patients were statistically comparable regarding demographic parameters, e.g., age, weight, sex, MPG, ASA (Table 1 and 2) (P > 0.05); and hemodynamic parameters, e.g., HR, NIBP, and SpO2, in pre-induction, postinduction and post-intubation periods (P > 0.05). However, total intubation time was longer in Group-AA (23.34 ± 3.98 sec) than Group-KV (20.42 ± 2.90 sec). There was statistically significant difference in total intubation time (P = 0.0008) (Table 3). All the intubation attempts in both the groups were successful. Total number of laryngoscope insertion attempts were less in Group-KV than Group-AA but the difference was statistically not significant (P = 0.460). Need for optimization maneuver such as external laryngeal manipulation was more in Group-AA (three patients) as compared to Group-KV (two patients) but difference was statistically not significant (P = 1.000). The CL score and mean POGO score were better in Group-KV than Group-AA but the difference was not significant statistically (P > 0.05). Thirty patients of Group-AA and thirty-two patients of Group-KV had CL grade-I, whereas five patients in Group-AA and only three patients of Group-KV had grade-IIa. The mean POGO score was also high in Group-KV (97.42 ± 6.10) as compared to Group-AA (95.71 ± 1.92), the difference was statistically significant (P = 0.420). Degree of difficult intubation (Likert scale) was found more in Group-AA than Group-KV however, there was no statistically significant difference (P = 0.861). The difference in the incidence of adverse effects such as airway trauma was statistically insignificant between the groups (P = 1.000). Other adverse effects such as esophageal intubation, bronchospasm and throat pain were not observed in any of the patient in both of the groups (Table 3).
4. Discussion
Very limited studies have been conducted on patients comparing AA and KV. In our study we compared the intubation efficacy of AA with that of KV(Channeled) on adult patients undergoing elective surgeries under general anesthesia. Our main aim was to compare total intubation time (in sec). We also assessed success rate, number of attempts, need of optimization maneuvers, POGO-score, CL-score, degree of difficulty of intubation (Likert scale) and adverse effects. In our study, the mean total intubation time for Group-AA was more than Group-KV and was statistically significant. In a similar study comparing Airtraq (but without Airview) with KV, the results were similar.13 The time to secure airway was significantly longer when using Airtraq (38 ± 18 sec) compared to KV (26 ± 11 sec). However, Airview feature was not used in the study and the anesthetist had to look through an eyepiece to visualize the glottis in Airtraq group. This might explain prolongation of mean intubation time in that study in group-A (Airtraq), when compared to intubation time by Airtraq-Airview in our study. In a study done on mannequins comparing intubating conditions and ease of intubation between AA and KV, the results were contrasting to our study.18 They observed that the time necessary to identify glottis to insert the tube and inflate its cuff, and to ventilate the lungs was significantly shorter with the Group-AA than Group-KVC. The difference in the result of the above study may be explained by the fact that their study was done on mannequins who do not replicate normal human anatomy completely. Our study had 100% success rate in both the groups while in a similar study all intubations performed with King Vision group were successful and only one intubation performed with Airtraq group was not successful (P > 0.05).13 The CL-view and POGO score obtained were reported better with the Group-KV in our study, however no significant difference was found between the two groups (P > 0.05). Another study which included paramedics and compared Airtraq with KV in a tactical setting, CL views between different VLSs were comparable; although they used the Airtraq with its eyepiece, external viewing of the intubation process was not possible.19 Another study on mannequins, the pre-intubation CL was statistically better with KV although during intubation, CL were similar in the two groups.18 In our study successful single attempt intubations were more in Group-KV, and Group-AA had higher number of second and third attempts, but the difference was statistically insignificant (P > 0.05). The number of attempts was statistically lower with KV when it was compared to Airtraq without Airview.17 VLS facilitates easy visualization of the glottis without a direct line of sight reducing the need of optimizing maneuvers. Optimization maneuver requirement was less in Group-KV. Many authors have documented reduced need of optimization maneuvers in VLS groups compared to conventional laryngoscope group.7,20 Although one study did not report any difference in Likert scale,18 our study found higher difficulty in Group-AA although statistically the difference was insignificant, which might be explained by the fact that KV had the better indirect laryngoscopic view than AA. Some authors reported more airway trauma more in Airtraq group, which was not significant as reported in our study.17
5. Conclusion
Considering the results of statistical analysis of our study, it can be concluded that both Airtraq® Airview and King Vision® provide satisfactory intubation conditions, but use of King Vision® might be preferable for endotracheal intubation in adult patients undergoing elective surgery as it has shorter total intubation time, other parameters being similar to Airtraq® Airview.
6. Limitations of the study
- The protocol did not allow blinding as it was impossible to conceal the airway device during insertion which was a possible source of bias.
- This study was conducted in a single center. Results cannot be generalized to the population of other parts of the country or other countries.
- Single user reflects only an individual skill level, which therefore, might not be representative for a larger population.
Single user approach is the strength of the study as it reduces inter-individual skill differences and reduces bias.
8. Data availability
The numerical data generated during this research is available with the authors.
9. Conflict of interest
No external or industry funding was involved in the study.
10. Authors’ contribution
MG: Concept and design of the study, acquisition, analysis and interpretation of data, drafting the paper, Final approval of the version
SS: Concept, revising the manuscript for intellectual content, final approval
DC: Interpretation of data, manuscript editing, final approval
CK: Analysis and interpretation of data, manuscript editing, final approval of the version
RK: Concept and design, revising it critically for intellectual content, final approval
11. References
- Apfelbaum JL, Hagberg CA, Caplan RA, Blitt CD, Connis RT, Nickinovich DG, et al. American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Practice guidelines for management of the difficult airway: an updated report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology. 2013 Feb;118(2):251-70. [PubMed] DOI: 1097/ALN.0b013e31827773b2
- Ajimi J, Nishiyama J, Masuda R, Shibata T, Furuya H, Hosoi S, et al. Usefulness of the Universal Adapter for Smartphones®in a Mannequin Study. Tokai J Exp Clin Med. 2018 Dec 20;43(4):139-42. [PubMed]
- Ford PN, Hamer C, Medakkar S. Use of the Airtraq in the difficult airway. Eur J Anaesthesiol. 2007 Aug;24(8):730-1. [PubMed] DOI: 1017/s0265021507000233
- Shah A, Patwa A, Burra A, Shah D, Gandhi B. Comparison of channeled blade with non-channeled Blade of King Vision™ videolaryngoscope for orotracheal intubation: A randomised, controlled, multicentric study. Airway. 2019;2:10-6. DOI: 4103/ARWY.ARWY_8_19
- Savoldelli GL, Schiffer E, Abegg C, Baeriswyl V, Clergue F, Waeber JL. Learning curves of the Glidescope, the McGrath and the Airtraq laryngoscopes: a manikin study. Eur J Anaesthesiol. 2009 Jul;26(7):554-8. [PubMed] DOI: 1097/eja.0b013e3283269ff4
- Ranieri D Jr., Filho SM, Batista S, Nascimento P Jr. Comparison of Macintosh and Airtraq laryngoscopes in obese patients placed in the ramped position. Anaesthesia 2012;67:980–5.[PubMed] DOI: 1111/j.1365-2044.2012.07200.x
- Elhadi SM, Rady WK, Elfadly A comparative study between the macintosh laryngoscope and the king vision video laryngoscope in endotracheal intubation. Res Opin Anesth Intensive Care. 2016;3:168-72. DOI: 10.4103/2356-9115.195881
- Hosalli V, Arjun BK, Ambi U, Hulakund S. Comparison of Airtraq™, McCoy™ and Macintosh laryngoscopes for endotracheal intubation in patients with cervical spine immobilisation: A randomised clinical trial. Indian J Anaesth. 2017 Apr;61(4):332-7. [PubMed] DOI: 4103/ija.IJA_517_16
- Paolini JB, Donati F, Drolet P. Review article: video-laryngoscopy: another tool for difficult intubation or a new paradigm in airway management? Can J Anaesth. 2013 Feb;60(2):184-91. [PubMed] DOI: 1007/s12630-012-9859-5
- Lewis SR, Butler AR, Parker J, Cook TM, Schofield-Robinson OJ, Smith AF. Videolaryngoscopy versus direct laryngoscopy for adult patients requiring tracheal intubation: a Cochrane Systematic Review. Br J Anaesth. 2017 Sep 1;119(3):369-83. [PubMed] DOI: 1093/bja/aex228
- Su YC, Chen CC, Lee YK, Lee JY, Lin KJ. Comparison of video laryngoscopes with direct laryngoscopy for tracheal intubation: a meta-analysis of randomised trials. Eur J Anaesthesiol. 2011 Nov;28(11):788-95. [PubMed] DOI: 1097/EJA.0b013e32834a34f3
- Panwar N, Vanjare H, Kumari M, Bhatia VS, Arora KK. Comparison of video laryngoscope and direct laryngoscopy during endotracheal intubation- A prospective comparative randomized study. Indian J Clin Anaesth.2020;7(3):438-43. DOI: 18231/j.ijca.2020.080
- Ali QE, Amir SH, Jamil S, Ahmad S. A comparative evaluation of the Airtraq and King Vision video laryngoscope as an intubating aid in adult patients. Acta Anaesthesiol Belg. 2015;66(3):81-5. [PubMed]
- O'Loughlin EJ, Swann AD, English JD, Ramadas R. Accuracy, intra- and inter-rater reliability of three scoring systems for the glottic view at videolaryngoscopy. Anaesthesia. 2017 Jul;72(7):835-9. [PubMed] DOI: 1111/anae.13837
- Cook TM. A new practical classification of laryngeal view. Anaesthesia. 2000 Mar;55(3):274-9. [PubMed] DOI: 1046/j.1365-2044.2000.01270.x
- Weiss M, Schwarz U, Gerber AC. Difficult airway management: comparison of the Bullard laryngoscope with the video-optical intubation stylet. Can J Anaesth. 2000 Mar;47(3):280-4. [PubMed] DOI: 1007/BF03018927
- Levitan RM, Kinkle WC, Levin WJ, Everett WW. Laryngeal view during laryngoscopy: a randomized trial comparing cricoid pressure, backward-upward-rightward pressure, and bimanual laryngoscopy. Ann Emerg Med. 2006 Jun;47(6):548-55. [PubMed] DOI: 1016/j.annemergmed.2006.01.013
- Schoettker P, Corniche J. The AirView Study: Comparison of Intubation Conditions and Ease between the Airtraq-AirView and the King Vision. Biomed Res Int. 2015;2015:284142. [PubMed] DOI: 1155/2015/284142
- Yun BJ, Brown CA 3rd, Grazioso CJ, Pozner CN, Raja AS. Comparison of video, optical, and direct laryngoscopy by experienced tactical paramedics. Prehosp Emerg Care. 2014 Jul-Sep;18(3):442-5. [PubMed] DOI: 3109/10903127.2013.864356
- Bhandari G, Shahi KS, Asad M, Bhakuni R. Airtraq(®) versus Macintosh laryngoscope: A comparative study in tracheal intubation. Anesth Essays Res. 2013;7(2):232-236. [PubMed] DOI: 4103/0259-1162.118971