The triple airway manoeuvre for insertion of the laryngeal mask airway in paralyzed patients

How does head position affect laryngeal vision with a video laryngeal mask airway?

Background

The Laryngeal Mask Airway Vision Mask (LMA VM) is a supraglottic airway device (SAD) with a vision guidance system. The ideal head and neck position for direct laryngoscopy is known, but the ideal position for placing a LMA is not. The objective of this study is to evaluate and compare the optimal position for placement of a video laryngeal mask airway.

Methods

This prospective, observational, transversal, and analytical study was performed in 72 consecutive patients. In the same patient, laryngeal vision was first assessed with the head and neck in the sniffing position and then with the head in the neutral position. Procedures were performed by the same investigator. The assessment of the laryngeal view was performed using two classifications: Cormack-Lehane classification and Brimacombe classification. The placement of the device was considered adequate when the Cormack-Lehane rating was between 1 and 2 and the Brimacombe rating between 2 and 4.

Results

In this study, 72 patients participated. In the assessment of the glottis using the Cormack-Lehane classification for fibre-optic view, laryngeal visibility was adequate in 64 (88.89%) patients in the neutral position and in 65 (90, 28%) patients in the sniffing position (p > 0.05). In the fibre-optic view of the glottis, evaluated using the Brimacombe classification, laryngeal visibility was adequate in 68 (93%) patients in the neutral position and in 69 (95%) patients in the sniffing position (p > 0.05). There was no statistically significant difference in the rate of success between the sniffing position (70 patients, 97.22% success rate) and the neutral position (67 patients, 93.06% success rate) during the first insertion attempt. Two patients required a second attempt in the sniffing position, while five patients required a second attempt in the neutral position.

Conclusion

An adequate sniffing position did not result in a better glottic view than the neutral position. Additional manoeuvres were equal in both positions. The head-neck position does not influence on the placement of a third-generation SAD.

Comparison between the standard method and the 30° curved tongue depressor-aided technique for insertion of a laryngeal mask airway: a randomized controlled trial

BACKGROUND

Laryngeal mask airway (LMA) has been increasingly used for airway management; however, LMA insertion can be difficult and cause adverse effects. Therefore, the rapid, safe, and effective insertion of LMA is necessary. This study aimed to compare the efficacy of the standard method with that of the 30° curved tongue depressor-aided technique for LMA insertion to determine the superior technique.

METHODS

This study included 154 patients aged 18-70 years (American Society of Anesthesiologists class I or II) scheduled for general anesthesia. The patients were randomly assigned to the standard LMA insertion group (Group C, n = 77) or the 30° curved tongue depressor-aided LMA insertion group (Group T, n = 77). The primary outcome evaluated was the first-attempt success rate. The secondary outcomes were the second-attempt success rate, insertion time, fiberoptic position grade, oropharyngeal leak pressure (OPLP), and adverse events.

RESULTS

The first-attempt success rate was significantly higher in Group T than in Group C (97.40% vs. 88.31%, P = 0.029). The second-attempt success rate (P = 0.209), insertion time (P = 0.340), fiberoptic position grade (P = 0.872), and OPLP (P = 0.203) were slightly improved in Group T; however, there was no statistical significance. Bleeding events were reduced in Group T than in Group C (6.49% vs. 14.29%); however, there was no statistical significance. The incidence of sore throat symptoms was significantly reduced in Group T than in Group C (5.19% vs. 15.58%, P = 0.035).

CONCLUSIONS

The curved tongue depressor-aided technique significantly improved the first-attempt success rate of LMA insertion and reduced the incidence of sore throat symptoms.

TRIAL REGISTRATION

KCT0004964; Registered at https://cris.nih.go.kr on April 27, 2020.

Supraglottic Airway Devices with Vision Guided Systems: Third Generation of Supraglottic Airway Devices

Supraglottic airway devices are currently widely used for airway management both for anaesthesia and emergency medicine. First-generation SADs only had a ventilation channel and did not provide protection from possible aspiration of gastric content if regurgitation occurred. Second-generation SADs are equipped with a gastric channel to allow the insertion of a gastric catheter and suctioning of gastric content. Additionally, the seal was improved by a change in the shape of the cuff. Some second-generation SADs were also designed to allow for intubation through the lumen using fiberscopes. Although the safety and efficacy of use of SADs are very high, there are still some issues in terms of providing an adequate seal and protection from possible complications related to misplacement of SAD. New SADs which allow users to choose the insertion scope and control the position of SAD can overcome those problems. Additionally, the Video Laryngeal Mask Airway may serve as an endotracheal intubation device, offering a good alternative to fibre-optic intubation through second-generation SADs. In this narrative review, we provide knowledge of the use of video laryngeal mask airways and the possible advantages of introducing them into daily clinical practice.

Comparison of Jaw-Thrust Maneuver and Standard Method for Airway Management with Laryngeal Mask Airway by Paramedics during Chest Compression: A Randomized, Crossover, Manikin Study

INTRODUCTION

The first priority of the primary survey of trauma care is airway management. For patients who have a known or suspected cervical spine injury, using the jaw-thrust maneuver is critical. It was hypothesized that the jaw-thrust maneuver would ease the insertion of the laryngeal mask airway (LMA) by moving the tongue forward from the palate and posterior pharyngeal wall.

STUDY OBJECTIVES

The aim of the study was to evaluate the effect of jaw-thrust maneuver on LMA insertion times of the paramedics with or without chest compression and with or without cervical stabilization in a manikin.

METHODS

Eleven experienced paramedics inserted LMA in jaw-thrust position and standard position in chest compression without cervical stabilization scenario, chest compression with cervical stabilization scenario, cervical stabilization without chest compression scenario, and the scenario where neither cervical stabilization nor chest compression were performed. The primary outcome of the study was the comparison of LMA insertion times for each method. The secondary outcome measures were first-pass success rates and the comparison of the difficulty level of each method.

RESULTS

During the LMA placement, performing the jaw-thrust maneuver instead of the standard method did not shorten the LMA insertion times. Adding chest compression and/or cervical stabilization did not complicate the LMA insertion. All of the LMA insertion attempts during the jaw-thrust maneuver and standard method were successful.

CONCLUSION

The findings of this study suggest that LMA insertion might be attempted both during the jaw-thrust maneuver and standard position in patients with or without chest compression and with or without cervical stabilization.

Features of new vision-incorporated third-generation video laryngeal mask airways

Numerous studies have shown that blindly inserted supraglottic airway devices (SADs) are sub-optimally placed in 50 to 80% of all cases. Placement under direct vision has been recommended. We describe the very first two new SADs of the third generation that incorporate a videoscope with flexible tip. Both devices are made up of two interlocking components-the SAD and a videoscope. The 3rd generation, direct vision SADs allow vision-guided insertion, corrective manoeuvres, if needed, and correct placement in the hypopharynx and possess additional features which permit insertion of a gastric tube and endotracheal intubation should the need arise. This article describes the two new devices' physical characteristics, features, rationale for use, advantages and limitations in comparison to existing devices. Each of the two new devices-the Video Laryngeal Mask (VLM^TM, UE Medical®) and the SafeLM® Video Laryngeal Mask System (SafeLM^TM VLMS, Magill Medical Technology®) consist of two parts: (a) a disposable 2nd generation SAD with a silicone cuff and an anatomically curved tube; and (b) a reusable patient-isolated videoscope and monitoring screen, with the flexible scope located into a specially-designed, blind-end channel terminating in the bowl of the SAD, preventing the videoscope from contacting patient body fluids in the SAD bowl. Third generation placement-under-direct-vision supraglottic airway devices possess several theoretical safety and ease of use advantages which now need to be validated in clinical use.

The case for a 3rd generation supraglottic airway device facilitating direct vision placement

Although 1st and 2nd generation supraglottic airway devices (SADs) have many desirable features, they are nevertheless inserted in a similar 'blind' way as their 1st generation predecessors. Clinicians mostly still rely entirely on subjective indirect assessments to estimate correct placement which supposedly ensures a tight seal. Malpositioning and potential airway compromise occurs in more than half of placements. Vision-guided insertion can improve placement. In this article we propose the development of a 3rd generation supraglottic airway device, equipped with cameras and fiberoptic illumination, to visualise insertion of the device, enable immediate manoeuvres to optimise SAD position, verify whether correct 1st and 2nd seals are achieved and check whether size selected is appropriate. We do not provide technical details of such a '3rd generation' device, but rather present a theoretical analysis of its desirable properties, which are essential to overcome the remaining limitations of current 1st and 2nd generation devices. We also recommend that this further milestone improvement, i.e. ability to place the SAD accurately under direct vision, be eligible for the moniker '3rd generation'. Blind insertion of SADs should become the exception and we anticipate, as in other domains such as central venous cannulation and nerve block insertions, vision-guided placement becoming the gold standard.

Comparison of the standard and triple airway maneuvering techniques for i-gel™ placement in patients undergoing elective surgery: a randomized controlled study

PURPOSE

The i-gel is a supraglottic airway device with non-inflatable cuff which can suffer insertion failure if its standard placement technique is implemented. The aim of this study was to compare the placement technique proposed by the manufacturer of i-gel with the triple airway maneuver in terms of successful device insertion time and first-attempt success.

METHODS

After ethics committee approval, 103 ASA I-III patients were randomly allocated to the standard or triple airway maneuver groups. In the standard Group, the i-gel was inserted in the sniffing position while, in the triple group, it was inserted using the triple airway maneuver consisting of head tilt, jaw thrust, and open mouth. The time taken for successful insertion, first-attempt success rate, i-gel position, airway complications, and hemodynamic responses were assessed.

RESULTS

Between the two groups patient characteristics were similar. Time for successful insertion was significantly shorter in the triple group (20 ± 7 s) than with the standard technique (32 ± 11 s; p < 0.001). Successful insertion at the first attempt was 78% and 92% for the standard and triple group, respectively (p = 0.092). The i-gel position, airway complications, and hemodynamic responses were similar in both groups.

CONCLUSION

The triple airway maneuver required less i-gel insertion time as compared with the standard placement technique. First-attempt success rates were similar with both techniques, although the triple airway maneuver was superior to the standard method as a rescue technique in failed insertions. We therefore recommend use of the triple airway maneuver in i-gel insertion.

A prospective randomized comparison of airway seal using the novel vision-guided insertion of LMA-Supreme® and LMA-Protector®

The laryngeal mask airways supreme (LMA-Supreme™) and protector (LMA-Protector™) are generally placed blindly, often resulting in a less than optimal position and vision-guided placement has been recommended. This prospective, randomized controlled study compared the efficacy of airway seal by measuring the oropharyngeal leak pressure in 100 surgical patients who underwent a variety of non-thoracic surgery under general anaesthesia, suitable with a supraglottic airway device. Patients were allocated to either the LMA-Supreme (n = 50) or LMA-Protector (n = 50) group. All insertions were performed under vision of a videolaryngoscope using an 'insert-detect-correct-as-you-go' technique with standardized corrective measures. Our primary endpoint, mean oropharyngeal leak pressure, was significantly higher in the LMA-Protector (31.7 ± 2.9 cm H₂O) compared to the LMA-Supreme (27.7 ± 3.5 cm H₂O) group (mean difference 4.0 cm H₂O, 95% confidence interval (CI) 2.7-5.3 cm H₂O, p < 0.001) after achieving a near-optimal fibreoptic position in the LMA-Protector (94%) and LMA-Supreme (96%) groups. No statistically significant differences were shown for secondary outcomes of alignment, number of insertion attempts and malpositions, and final anatomical position as scored by fibreoptic evaluation. Corrective manoeuvres were required in virtually all patients to obtain a correct anatomically positioned LMA. Position outcomes of the two devices were similar except for the proportion of procedures with folds in the proximal cuff (90% LMA-Supreme vs. 2% LMA-Protector, p < 0.001), the need for intracuff pressure adjustments (80% LMA-Supreme vs. 48% LMA-Protector, p = 0.001) and size correction (18% LMA-Supreme vs. 4% LMA-Protector, p = 0.025). In conclusion, a higher oropharyngeal leak pressure can be achieved with LMA-Protector compared to LMA-Supreme with optimal anatomical position when insertion is vision-guided.

Ultrasonographic assessment of airway

Ultrasound is gaining increasing popularity among anesthesiologists as it is readily available and provides real-time imaging for various procedures. It is considered as a “visual stethoscope” of the anesthesiologist. After establishing its use in regional blocks and central venous catheter insertion, it is now finding increasing use in anticipation of difficult airway and securing and maintaining it. It has challenged the classical approach of clinical assessment of airway and allows more dynamic bedside assessment. This article attempts to briefly outline the role of ultrasound and its applications for airway management in patients.

An Anesthesiologist's Perspective on the History of Basic Airway Management: The "Modern" Era, 1960 to Present

This fourth and last installment of my history of basic airway management discusses the current (i.e., "modern") era of anesthesia and resuscitation, from 1960 to the present. These years were notable for the implementation of intermittent positive pressure ventilation inside and outside the operating room. Basic airway management in cardiopulmonary resuscitation (i.e., expired air ventilation) was de-emphasized, as the "A-B-C" (airway-breathing-circulation) protocol was replaced with the "C-A-B" (circulation-airway-breathing) intervention sequence. Basic airway management in the operating room (i.e., face-mask ventilation) lost its predominant position to advanced airway management, as balanced anesthesia replaced inhalation anesthesia. The one-hand, generic face-mask ventilation technique was inherited from the progressive era. In the new context of providing intermittent positive pressure ventilation, the generic technique generated an underpowered grip with a less effective seal and an unspecified airway maneuver. The significant advancement that had been made in understanding the pathophysiology of upper airway obstruction was thus poorly translated into practice. In contrast to consistent progress in advanced airway management, progress in basic airway techniques and devices stagnated.

[Comparison of three different insertion techniques with LMA-Unique™ in adults: results of a randomized trial]

BACKGROUND

The triple airway maneuver insertion technique allowed faster insertion of the LMA. This study compared three different insertion techniques of the laryngeal mask airway-Unique™.

METHODS

One hundred and eighty ASA I-II patients aged 18-65 years were included into the study. Patients were randomly allocated to the standard, rotational and triple airway maneuver (triple) group. In the standard group (n=60), the LMA (Laryngeal Mask Airway) was inserted with digital intraoral manipulation. In the triple group (n=60), the LMA was inserted with triple airway maneuver (mouth opening, head extension and jaw thrust). In the rotational group (n=60), LMA was inserted back-to-front, like a Guedel airway. Successful insertion at first attempt, time for successful insertion, fiber optic assessment, airway morbidity and hemodynamic responses were assessed.

RESULTS

Successful insertion at the first attempt was 88.3% for the standard, 78.3% for the rotational and 88.3% for the triple group. Overall success rate (defined as successful insertion at first and second attempt) was 93% for the standard, 90% for the rotational and 95% for the triple group. Time for successful insertion was significantly shorter in the triple group (mean [range] 8.63 [5-19]s) compared with the standard (11.78 [6-24]s) and rotational group (11.57 [5-31]s). Fiber optic assessment, airway morbidity and hemodynamic responses were similar in all groups.

CONCLUSIONS

Rotational and triple airway maneuver insertion techniques are acceptable alternatives. Triple airway maneuver technique shows higher overall success rates and allows shorter insertion time for LMA insertion and should therefore be kept in mind for emergent situations.

Standard versus Rotation Technique for Insertion of Supraglottic Airway Devices: Systematic Review and Meta-Analysis

PURPOSE

Supraglottic airway devices have been widely utilized as an alternative to tracheal intubation in various clinical situations. The rotation technique has been proposed to improve the insertion success rate of supraglottic airways. However, the clinical efficacy of this technique remains uncertain as previous results have been inconsistent, depending on the variable evaluated.

MATERIALS AND METHODS

We systematically searched PubMed, Embase, and the Cochrane Central Register of Controlled Trials in April 2015 for randomized controlled trials that compared the rotation and standard techniques for inserting supraglottic airways.

RESULTS

Thirteen randomized controlled trials (1505 patients, 753 with the rotation technique) were included. The success rate at the first attempt was significantly higher with the rotation technique than with the standard technique [relative risk (RR): 1.13; 95% confidence interval (CI): 1.05 to 1.23; p=0.002]. The rotation technique provided significantly higher overall success rates (RR: 1.06; 95% CI: 1.04 to 1.09; p<0.001). Device insertion was completed faster with the rotation technique (mean difference: -4.6 seconds; 95% CI: -7.37 to -1.74; p=0.002). The incidence of blood staining on the removed device (RR: 0.36; 95% CI: 0.27 to 0.47; p<0.001) was significantly lower with the rotation technique.

CONCLUSION

The rotation technique provided higher first-attempt and overall success rates, faster insertion, and a lower incidence of blood on the removed device, reflecting less mucosal trauma. Thus, it may be considered as an alternative to the standard technique when predicting or encountering difficulty in inserting supraglottic airways.

Comparison of the trapezius squeezing test and jaw thrust as indicators for laryngeal mask airway insertion in adults

BACKGROUND

The purpose of this study was to compare the effectiveness of the trapezius squeezing test with that of the jaw thrust maneuver as clinical indicators of adequate conditions for laryngeal mask airway (LMA) insertion in adults under sevoflurane anesthesia.

METHODS

One hundred adult patients of ASA physical status 1 or 2 undergoing minor surgical procedures were randomly allocated to the T (trapezius squeezing, n = 50) group or the J (jaw thrust, n = 50) group. The LMA was inserted immediately after the loss of response to trapezius squeezing or jaw thrust. Successful and unsuccessful attempts were recorded. An unsuccessful attempt was defined as the occurrence of coughing, gagging, gross purposeful movements, breath-holding, laryngospasm, or an SpO(2) < 90% during LMA insertion. Insertion time, end-tidal sevoflurane concentration, mean arterial pressure, and heart rate were recorded.

RESULTS

The incidence of successful attempts was significantly higher in the T than in the J group (48/50 vs. 36/50, respectively).

CONCLUSIONS

The trapezius squeezing test is a superior indicator of an adequate condition for LMA insertion compared to the jaw thrust maneuver in adults under sevoflurane anesthesia.

The Soft Seal disposable laryngeal mask airway in adults: comparison of two insertion techniques without intra-oral manipulation

We investigated whether insertion of the disposable Soft Seal laryngeal mask airway (SSLM) was successful without intra-oral digital manipulation. One hundred patients undergoing anaesthesia using the SSLM were randomly assigned into two groups. Insertion was performed by either a direct or a rotational technique, both without intra-oral digital manipulation. The primary outcome measure was successful insertion at first attempt. Other outcomes included insertion time, fibreoptic assessment of the airway view and airway morbidity. The first attempt success rate was higher (98%) with the direct technique than with the rotational technique (75%; p = 0.002) but insertion time was faster with the latter method (mean [range] 15 [8-50] s) than with the direct method (20 [8-56] s; p = 0.035). Fibreoptic assessment and airway morbidity were similar in both groups. We conclude that the SSLM can be successfully inserted without intra-oral digital manipulation.

A comparison of the cuffed oropharyngeal airway (COPA) with the laryngeal mask airway (LMA) during manually controlled positive pressure ventilation

STUDY OBJECTIVE

To examine the cuffed oropharyngeal airway (COPA) during positive pressure ventilation (PPV) and to compare its reliability and efficacy with the laryngeal mask airway (LMA).

DESIGN

Prospective, randomized, controlled trial.

SETTING

University Hospital.

PATIENTS

60 adult ASA physical status I and II patients scheduled for urologic surgery.

INTERVENTIONS

Patients were randomly assigned to be ventilated with a COPA (n = 33) or a LMA (n = 27) during a standardized anesthetic procedure. Following preoxygenation and induction with alfentanil and propofol, the respective airways were inserted. Patients were ventilated manually with the reservoir bag of the anesthesia respirator. Inspiratory airway pressure was limited to 20 cm H2O, and the target tidal volume was 7 ml/kg. Respiratory rate was adjusted to achieve an end-tidal pressure of carbon dioxide of 35 mmHg. Anesthesia was maintained with propofol, nitrous oxide in oxygen, and alfentanil, as appropriate.

MEASUREMENTS AND MAIN RESULTS

We evaluated ease of insertion (nominal scale: easy, moderate, difficult, or impossible) and recorded the number of maneuvers performed during insertion until an airtight seal of the airway was achieved. Reliability for "hands free" ventilation--defined as ventilation without the need to further augment the position of the airway device manually--was determined (nominal scale: adequate ventilation, adequate ventilation with manual assistance, and inadequate ventilation leading to airway change). Ventilation and oxygenation parameters were derived from the anesthesia respirator and a capillary blood gas sample, respectively. The incidence of laryngopharyngeal discomfort and the amount of salivation were assessed by nominal scales. The COPA was easier to insert than the LMA (p < 0.001), but more positional maneuvers (p < 0.001) were necessary with this device. "Hands free" ventilation was achieved less often with the COPA (p < 0.02). Ventilation and oxygenation were comparable with both devices. The COPA was associated with less salivation (p < 0.01) and laryngopharyngeal discomfort (p < 0.05) than the LMA.

CONCLUSION

Although effective ventilation can be accomplished with both devices, the LMA is more reliable for "hands free" ventilation than the COPA. The lower incidence of laryngopharyngeal discomfort and salivation with the COPA may be beneficial for patients at risk for developing laryngospasm.

Cricoid pressure impedes positioning and ventilation through the laryngeal mask airway

PURPOSE

To assess the effect of cricoid pressure on the positioning of and ventilation through the laryngeal mask airway (LMA).

METHODS

In a double-blind, randomized design, the LMA was inserted with (CP[+] group, n = 20) or without double-handed cricoid pressure (CP[-] group, n = 20). Ventilation through the LMA was assessed by measuring expiratory tidal volume and judged as adequate when a mean expiratory tidal volume of > or = 10 ml.kg-1 could be obtained. The LMA position was examined by fibreoscopy. The position of the mask relative to the cricoid cartilage and the cervical spine was radiologically examined (n = 10 in each group).

RESULTS

Ventilation was adequate in all patients in the CP[-] group but in only five patients (25%) of the CP[+] group (P < 0.001). The glottis was visible fibreoptically below the mask aperture in all patients in the CP[-] group, but in only three patients in the CP[+] group (P < 0.001). Fibreoscopy showed that the mask was not inserted far enough in the remaining 17 patients of the CP[+] group. The reason for unsuccessful ventilation in the CP[+] group was excessive gas leakage (n = 2) and/or partial or complete airway obstruction (n = 13), which was noted fibreoptically. The radiographs showed that the tip of the mask in the CP[-] group was located below the level of the cricoid cartilage (C6 or C7 vertebra). The mask tip in the CP[+] group was above this level (C4 or C5 vertebra) (P < 0.01).

CONCLUSION

Cricoid pressure impedes positioning of and ventilation through the LMA.