Laryngeal mask airway: a more successful method of insertion

Efficacy and safety of three inflation methods of the laryngeal mask airway Ambu® Auraonce™: a randomized controlled study

The laryngeal mask airway (LMA) is commonly used for airway management. Cuff hyperinflation has been associated with complications, poor ventilation and increased risk of gastric insufflation. This study was designed to determine the best cuff inflation method of AuraOnce™ LMA during bronchoscopy and EBUS (Endobronquial Ultrasound Bronchoscopy) procedure. We designed a Randomized controlled, doble-blind, clinical trial to compare the efficacy and safety of three cuff inflation methods of AuraOnce™ LMA. 210 consenting patients scheduled for EBUS procedure under general anesthesia, using AuraOnce™ LMA were randomized into three groups depending on cuff insufflation: residual volume (RV), half of the maximum volume (MV), unchanged volume (NV). Parameters regarding intracuff pressure (IP), airway leak pressure (OLP), leakage volume (LV) were assessed, as well as postoperative complications (PC). 201 (95.7%) patients completed the study. Mean IP differed between groups (MV: 59.4 ± 32.4 cm H2O; RV: 75.1 ± 21.1 cm H2O; NV: 83.1 ± 25.5 cmH20; P < 0.01). The incidence of IP > 60 cmH2O was lower in the MV group compared to the other two (MV: 20/65(30.8%); RV:47/69 (68.1%); NV 48/67 (71.6%); p < 0.01). The insertion success rate was 89,6% (180/201) at first attempt, with no difference between groups (p = 0.38). No difference between groups was found either for OLP (p = 0.53), LV (p = 0.26) and PC (p = 0.16). When a cuff manometer is not available, a partial inflation of AuraOnce™ LMA cuff using MV method allows to control intracuff pressure, with no significant changes of OLP and LV compared to RV and NV insufflation method.Registration clinical trial: NCT04769791.

Comparison of the ease of insertion and complications of the classical method of laryngeal mask airway insertion with an alternative method

Background and Goal

Laryngeal mask airway (LMA), a supraglottic device for airway management and ventilation, is used both in emergencies, out of the operating room, and in the operating room during general anesthesia. This study aims to compare the success rate and complications of the classic insertion method (with a semi-inflated cuff) and another technique using the index and middle fingers of the second hand to prevent retroversion of the mask tip (alternative method).

Methods and Materials

In total, 288 patients scheduled for short-time ophthalmologic elective surgeries under general anesthesia were randomly allocated to two groups for LMA placement; group C, classical method (with semi-inflated cuff), and group A, alternative method. Difficulty in placement, insertion duration, and the number of attempts were studied. Assessment of pharyngolaryngeal complications (blinded assessor) was made at the time of LMA removal.

Findings

The success rate of LMA insertion in the classic group with first, second, and third attempts were 86.3%, 93.5%, and 94.2%, respectively, whereas in the alternative group these values in the first and second attempts were 98.6% and 100%, respectively, and there was no need for the third attempt. Insertion time was not significantly different. There was no meaningful difference between the rate of the bloody streak on the mask (P = 0.37) and the incidence of sore throat (P = 0.048) in the two groups of the study.

Conclusion

This newly introduced technique can be considered as an alternative method when a difficult insertion situation is suspected or the classic technique of insertion has failed.

A new maneuver for classical laryngeal mask airway insertion: Prospective randomized study

Background/Aim: Laryngeal mask airway (LMA) has been frequently used for airway management. But the satisfaction of the insertion and trauma at insertion remain problems. We present a new insertion maneuver for classical LMA (cLMA) with a partially inflated cuff and examine its success and complication rate. Methods: In 4 months, 158 patients who were classified as ASA I–III and older than 18 years old and were planned for LMA were included in this study consecutively (according to the study design, one patient was excluded during the study). Emergency cases, patients with any contraindications with LMA, patients who were expected to undergo surgery for more than 2 h, patients with preoperative respiratory tract infection or sore throat, patients undergoing oral or nasal surgery, and patients with aspirated oropharyngeal secretions after removal of LMA was excluded from the study. Age, gender, height, weight, ASA scores, comorbidities, and the duration of anesthesia and surgery of the patients were recorded. One-hundred-fifty-seven consecutive patients were randomized into two groups by a coin toss [control group (group C) and study group (group S)]. The groups were compared in terms of LMA insertion success, the number of insertion attempts, the presence of blood on the LMA or in secretions, and postoperative sore throat. Classical Laryngeal Mask Airway was inserted with Brain’s standard technique in group C and with the new technique in group S. In the new technique, the head and neck of the patient were supported in a straight position, the mouth was opened, cLMA was held with a dominant hand from the tube part and inserted until the tip touches to the oropharynx. The index finger of the non-dominant hand was inserted into the mouth to pass by the cLMA and reach the tip of the cLMA. The tip of cLMA was directed to the caudal by the index finger. Then, cLMA was inserted by the guidance of the index finger until it reached the triangular base of the oropharynx. Results: There was no statistically significant difference in terms of demographic data and placement success; placement success was better in the study group (100% versus 98.6% and P = 0.45). Similarly, the count of attempts was better in the study group. The mean attempt number was 1.11 in group S and 1.28 in group C (P = 0.02). Also, blood on LMA was seen to be more common in group C (P = 0.04). There were no statistical differences in sore throat, but it was less seen in group S. Conclusion: The new maneuver was better than the standard technique and easy to use in daily practice.

Standard digit-based versus 90° rotation technique for supraglottic airway device insertion: a meta-analysis of randomized controlled trials

BACKGROUND

Prompt insertion and placement of supraglottic airway (SGA) devices in the correct position are required to secure the airway. This meta-analysis was performed to validate the usefulness of the 90° rotation technique as compared with the standard digit-based technique for the insertion of SGA devices in anesthetized patients in terms of insertion success rate, insertion time, and postoperative complications.

METHODS

A literature search of PubMed, EMBASE, CENTRAL, CINAHL, Scopus, and Web of Science was conducted. Randomized controlled trials, without limitations on publication period, language, journal, or region, until July 2021, that compared the 90° rotation and the standard digit-based techniques for insertion of SGA devices in anesthetized patients were included.

RESULTS

The first-attempt (risk ratio [RR]: 1.16, 95% CI [1.09, 1.25], P < 0.001) and overall success rates (RR: 1.06, 95% CI [1.03, 1.09], P < 0.001) were significantly higher in the 90° rotation group. The insertion time was shorter in the 90° rotation group (mean difference: -4.42 s, 95% CI [-6.70, -2.15 s], P < 0.001). The incidences of postoperative sore throat (RR: 0.63, 95% CI [0.49, 0.83], P < 0.001) and blood staining (RR: 0.28, 95% CI [0.20, 0.39], P < 0.001) were lower in the 90° rotation group.

CONCLUSIONS

The use of the 90° rotation technique increases the success rate of SGA device insertion and decreases postoperative complications as compared with that of the standard digit-based technique in anesthetized patients.

Incidence of postoperative sore throat after using a new technique of insertion of a second generation Laryngeal Mask Airway: A randomised controlled trial

BACKGROUND

Sore throat is a common complication after Laryngeal Mask Airway Supreme (SLMA) insertion.

OBJECTIVE

The aim of this study was to determine whether a new SLMA insertion technique (not removing the pilot tube blocker before insertion) lowers the incidence of sore throat in the postanaesthesia care unit (PACU).

DESIGN

A prospective, single-centre, parallel randomised controlled trial.

SETTING

Operating room and PACU at a hospital in China from June to September 2019.

PATIENTS

Four hundred and eight patients aged 18 to 65 years with American Society of Anaesthesiologists physical status class I or II who were scheduled for elective surgery requiring anaesthesia and SLMA insertion.

INTERVENTIONS

Leaving the blocker at the end of the pilot tube in situ (this blocker keeps the valve open and the balloon remains partially inflated but will deflate with pressure) or removing the blocker and actively deflating the cuff before SLMA insertion.

MAIN OUTCOME MEASURES

The primary outcome was the incidence of postoperative sore throat in the PACU. The secondary outcomes included sore throat severity (Prince Henry Hospital Pain Score), first-attempt success rate, ease of insertion, time to successful SLMA insertion, oropharyngeal leak pressure, grade of view on fibreoptic bronchoscopy (indicating the accuracy of SLMA positioning) and adverse events.

RESULTS

The incidence of sore throat was 33/204 (16.2%) in the nonremoval group, and 65/204 (31.9%) in the removal group (P < 0.001). The first-attempt success rate was 174/204 (85.3%) in the nonremoval group and 150/204 (73.76%) in the removal group (P = 0.003; relative risk 1.160, 95% CI 1.049 to 1.282). The Kaplan--Meier curves showed that the insertion time in the nonremoval group was shorter (log-rank P = 0.01).

CONCLUSION

The new insertion technique, leaving the blocker attached to the end of the pilot balloon, resulted in a reduced incidence and severity of postoperative sore throat in the PACU, and an improved first-attempt success rate and the accuracy of SLMA positioning.

TRIAL REGISTRATION

Chinese Clinical Trial Registry identifier: ChiCTR1900023022.

Comparative study of effective-site target controlled infusion with standard bolus induction of propofol for laryngeal mask airway insertion

Several studies demonstrated induction of anesthesia with different plasma target-controlled infusion (TCI) of propofol for LMA insertion. However, there has been no study to compare the standard bolus propofol induction with the effective site TCI for LMA insertion. Objective: Compare the efficacy of induction of anesthesia with propofol for LMA insertion between the effective-site TCI, using 6 μg/mL, and the standard bolus propofol dose of 2.5 mg/kg in elective surgical patients. Methods: A randomized, prospective, single-blinded, clinical study was used for this study. Seventy-eight unpremedicated patients, American Society of Anesthesiologists (ASA) physical status I and II undergoing elective surgical procedure were randomly allocated between two groups. Group 1 received the standard bolus propofol dose of 2.5 mg/kg. Group 2 received effective site TCI (Schnider model) dose of 6 μg/mL for LMA insertion. The hemodynamics and anesthetic depth (Bispectral index score) were monitored and recorded during and immediately after LMA insertion. The number of insertion attempted, insertion quality score, induction time, and propofol doses used were recorded and compared between groups. Results: The success rate of first insertion attempt was equal in both groups (92.3%). There was no significant hemodynamic response difference between the groups during pre-induction, induction, insertion, and post insertion period. The BIS score was significantly lower during post insertion period in group 1 (51.4+11.0) than group 2 (58.4+3.2) (p=0.013). The propofol doses in group 2 were significantly lower than in group 1 (110.6+14.8 vs. 153.5+21.5) (p <0.001). Patients in group 2 required significantly more induction time than group 1 (146.9+42.3 vs. 103.4+33.6 (p <0.001). Conclusion: Propofol induction with TCI provided equal success rate as compared with standard bolus propofol induction for LMA insertion and insertion quality score. TCI significantly lowered the propofol consumption when compared with the standard 2.5 mg/kg propofol dose.

A Prospective Randomised Clinical Trial for the Comparison of Two Techniques for the Insertion of Proseal Laryngeal Mask Airway in Adults-Index Finger Insertion Technique versus 90° Rotation Technique

OBJECTIVE

The 90° rotation technique for inserting the Proseal laryngeal mask airway (PLMA) is reported to be better than the standard index finger insertion technique to improve the insertion success rate. The objective of this study was to evaluate and compare the ease of insertion through the 90° rotation and standard insertion techniques in terms of number of attempts, duration of insertion and occurrence of complications.

METHODS

One hundred and twenty adult patients were allocated to either a standard technique group or rotation technique group with 60 patients in each. In the rotation technique group, the entire cuff of the PLMA was placed in the patient's mouth in a midline approach without finger insertion, rotated 90° counter-clockwise around the patient's tongue, advanced and rotated back until resistance was felt.

RESULTS

The success rate of the rotation technique group at the first insertion attempt was greater than that of the standard index finger insertion technique (98% vs. 78%; p=0.001), and less time for insertion was required (11.88±3.62 s vs. 25.98±10.92 s; p<0.0001). The incidence of post-operative sore throat was lower (15% vs. 38.34%; p=0.0067), and blood staining on the PLMA was less (11.7% vs. 45%; p<0.0001). The increase in the mean arterial pressure was more in the standard technique group.

CONCLUSION

The 90° rotation technique has a higher success rate at first insertion attempt for inserting the ProSeal LMA than the index finger insertion technique with less time for insertion and fewer side effects.

Comparison of trapezius squeeze test and jaw thrust as clinical indicators for laryngeal mask airway insertion in spontaneously breathing children

Background and Aims:

It is not known whether trapezius squeeze test (TPZ) is a better clinical test than jaw thrust (JT) to assess laryngeal mask airway (LMA) insertion conditions in children under sevoflurane anesthesia.

Material and Methods:

After the Institutional Ethics Committee approval and written informed parental consent, 124 American Society of Anesthesiologists I and II children of 2–8 years of age undergoing minor surgical procedures were randomized into TPZ and JT groups. The children were induced with 8% sevoflurane in oxygen at a fresh gas flow of 4 L/min. TPZ or JT was performed after 1 min of start of sevoflurane and then every 20 s till the test was negative, when end-tidal (ET) sevoflurane concentration was noted. Classic LMA of requisite size was inserted by a blinded anesthetist and conditions at the insertion of LMA, insertion time, and the number of attempts of LMA insertion were recorded.

Results:

The mean LMA insertion time was significantly longer (P < 0.001) for TPZ (145 ± 28.7 sec) compared to JT group (111.8 ± 31.0 sec). ET sevoflurane concentration at the time of LMA insertion was comparable in the two groups. LMA insertion conditions were similar in the two groups. There was no difference between the two groups regarding total number of attempts of LMA insertion. Heart rate (HR) decreased in both groups after LMA insertion (P < 0.001) but TPZ group had significantly lower HR compared with the JT group up to 5 min after LMA insertion (P = 0.03).

Conclusion:

Both JT and TPZ are equivalent clinical indicators in predicting the optimal conditions of LMA insertion in spontaneously breathing children; however, it takes a longer time to achieve a negative TPZ squeeze test.

A comparison of classic laryngeal mask airway insertion between lightwand- and standard index finger-guided techniques

STUDY OBJECTIVE

To compare the efficacy of lightwand-guided classic laryngeal mask airway (cLMA) real-time insertion technique with the standard recommended index finger-guided insertion technique.

DESIGN

Prospective, randomized controlled study.

SETTING

University-affiliated hospital.

PATIENTS

Three hundred patients undergoing minor gynecological or orthopedic surgeries under general anesthesia using the cLMA as an airway management tool.

INTERVENTIONS

Patients were randomly divided into either lightwand-guided group or standard group.

MEASUREMENTS

Fiberoptic bronchoscopy was used to determine the cLMA position after a cLMA was inserted. The first attempt and total success rates of the cLMA insertion, insertion time, distances from the end of cLMA pilot tube to the upper central incisors, views of fiberoptic bronchoscopy, blood staining, tidal volume, airway pressure, end-tidal CO2, SpO2, noninvasive hemodynamic parameters, and others were compared.

MAIN RESULTS

The cLMA was all successfully inserted within 3 attempts except for 2 patients in the standard group. The success rates of lightwand-guided insertion technique at first attempt were significantly higher than standard insertion technique; the ideal view rates assessed by fiberoptic bronchoscopy in lightwand-guided group patients were also significantly higher than in standard group patients, but the insertion time of first successful attempt was similar; the blood staining rates on the cLMA in lightwand-guided group patients were significantly less than in standard group patients. The depths of cLMA insertion in standard group patients were significantly deeper than those in lightwand-guided group patients. There was no significant difference in end-tidal CO2, SpO2, airway pressure, and hemodynamic variables.

CONCLUSION

Lightwand-guided cLMA insertion technique can provide a more objective indicator for correct cLMA positioning, higher first attempt success rates, better glottic views, and less damage to oropharyngeal or esophagus tissues than standard index finger-guided cLMA insertion technique.

Clinical efficacy of the classic laryngeal mask airway in elderly patients: a comparison with young adult patients

Background

The elderly have been reported to show anatomical and physiologic changes in the upper airway, which might affect the supraglottic airway (SGA) performance in geriatric populations. This study aimed to evaluate the clinical efficacy of the classic laryngeal mask airway (LMA-C) in the elderly compared with young adult patients.

Methods

Fifty patients aged 65-85 years (elderly group) and 50 patients aged 20-40 years (young group) who were scheduled for surgery using the LMA-C for general anesthesia were enrolled in this prospective, non-randomized, comparative study. Manipulations required during insertion, success rate, insertion time, oropharyngeal leak pressure, gastric insufflation, and intraoperative inadequate ventilation with the LMA-C were assessed. Fiberoptic evaluation was used to determine the position of the LMA-C.

Results

In the elderly group, the insertion success rate on the first attempt was significantly lower than that in the young group (84 vs. 96%, P = 0.02). The insertion time in the elderly group was significantly longer than that in the young group (28.5 ± 19.6 vs. 22.2 ± 6.4 seconds, P = 0.001). However, there was no difference in oropharyngeal leak pressure or fiberoptic grade between the two groups after proper placement of the LMA-C. During the surgery, inadequate ventilation events occurred more frequently in the elderly group than in the young group (31.3 vs. 4.0%, P < 0.001).

Conclusions

The clinical efficacy of the LMA-C in elderly patients was inferior to that in young adult patients. Therefore, further studies are required to determine the type of SGA that can provide excellent clinical efficacy in the geriatric population.

A comparative study of Laryngeal Mask Airway size 1 vs. i-gel size 1 in infants undergoing daycare procedures

BACKGROUND

The i-gel size 1 is a relatively new, single use, second generation supraglottic airway device. This prospective, randomized, observational study compares the suitability of the i-gel size 1 with the classical Laryngeal Mask Airway (cLaryngeal Mask Airway) size 1 in pediatric patients undergoing elective daycare procedures.

METHODS

Forty ASA I and II children (2-5 kg body weight) were randomized to two groups of 20 each, to receive either the i-gel or the cLaryngeal Mask Airway as an airway device. The primary outcome variable was oropharyngeal seal pressure (OSP). We also assessed ease of insertion, number of insertion attempts, time taken for successful insertion and any intra-operative complications.

RESULTS

Demographic data did not differ between the two groups. The OSP with the i-gel was 22.30 ± 4.72 cm H2O as compared to 18.05 ± 1.95 cm H2O with the cLaryngeal Mask Airway and the difference was statistically significant (P = 0.001). Displacement of the airway device following change of position was reported less often with the i-gel as compared to the cLaryngeal Mask Airway [n = 1 (5%) vs. n = 5 (35%), P = 0.04]. There were no major complications with either device and rest of all the variables were comparable with both the devices.

CONCLUSIONS

The OSP of the i-gel size 1 was higher than that of the cLaryngeal Mask Airway. This was statistically significant, although may not be of clinical significance. The i-gel size 1 is less prone to displacement during position changes. However, being a preliminary study carried out on a small number of patients, further trials are warranted to come to any definite conclusion.

Laryngeal mask airway insertion by classic and thumb insertion technique: a comparison

We evaluated the efficacy of an alternative technique, for insertion of the silicone laryngeal mask airway (LMA) Classic™ in 40 American Society of Anesthesiologists grade ASA I and II patients scheduled for elective surgery. In group I (Index Finger group), the LMA was inserted by the classic index finger technique and, in group T (Thumb Insertion group), the thumb insertion technique was used. Ease of insertion, fiberoptic laryngoscopic position, cuff pressures and laryngopharyngeal morbidity were assessed in both study groups. On statistical analysis, both groups were comparable in all respects. From our study it can be concluded that thumb insertion is an effective insertion technique for the LMA Classic™.

Laryngeal mask airway insertion in adults: comparison between fully deflated and partially inflated technique

PURPOSE

The laryngeal mask airway (LMA) is a supraglottic airway device designed to seal around the laryngeal inlet. A controlled study was designed to compare the effectiveness and complications in inserting the LMA when the cuff is fully deflated and partially inflated.

MATERIALS AND METHODS

American Society of Anesthesiologists physical status I or II 172 female patients scheduled for gynecologic procedures were included in this study. Patients were randomly allocated into one of the two groups; fully deflated (n=86) and partially inflated group (n=86). A size #4 LMA was inserted. The number of attempts, time taken for successful insertion, grade of leak, grade of fiberoptic view, and complications were evaluated.

RESULTS

All 172 patients completed the study protocol. The number of attempts, time taken for successful insertion, and grade of leak were not significantly different between the two groups. The grade of fiberoptic view and complications were lower in the fully deflated group.

CONCLUSION

The fully deflated method is more accurate and safe because of better fiberoptic view and lesser complications than the partially inflated group.

A novel method for laryngeal mask airway size selection in paediatric patients

CONTEXT

The successful use of the laryngeal mask airway in children partly depends on the correct selection of size. Most anaesthesiologists rely on the weight-based table which is often difficult to remember. A simple method allowing an adequate choice of the correct size may be highly desirable.

OBJECTIVES

To test the hypothesis that the size of the external ear (pinna) of the child may be used as proxy for the required size of laryngeal mask airway.

DESIGN

A descriptive study.

SETTING

King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia.

PATIENTS

Two hundred and ten paediatric patients aged 6 months to 15 years, of either sex, American Society of Anesthesiologists (ASA) 1-2 and scheduled for routine ophthalmological procedures from 1 March to 31 December 2010. Emergency cases, patients with a full stomach or with a history of any oropharyngeal lesion other than tonsillar hypertrophy were excluded.

MAIN OUTCOME MEASURES

The size of the external ear was measured with a ruler in vertical and horizontal dimensions in the first 30 patients, and visually evaluated for the remaining patients. For all, the nearest corresponding size of partially inflated laryngeal mask airway was chosen and inserted after induction. The correct placement was assessed using predefined criteria.

RESULTS

Insertion and good ventilation was achieved in 196 (93.3%) on first attempt. Fourteen patients (6.7%) required a second attempt and the main reason for failure was an audible leak because of smaller size.

CONCLUSION

Choosing the size of the laryngeal mask airway in children according to the size of the external ear was associated with a success rate of 93% which is comparable with that reported in the literature when the tables are used. This simple method may allow a rapid choice of the correct size of laryngeal mask airway and may eliminate the need to remember different tables or formulae.

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 90° rotation technique improves the ease of insertion of the ProSeal™ laryngeal mask airway in children

BACKGROUND

A previous study using a 180° rotation to insert the ProSeal™ laryngeal mask airway (LMA ProSeal) in children did not show improvement over the standard technique. We used a 90° rotation technique to insert the LMA ProSeal in pediatric patients and compared ease of insertion and pharyngeal trauma with the standard technique.

METHODS

This prospective randomized controlled study included 126 patients aged three to nine years. Anesthesia was induced with thiopental and rocuronium, and the LMA ProSeal used in the study ranged in size from 2 to 3 depending on the patient's body weight. In the control group (n = 63), the LMA ProSeal was inserted using the index finger. In the rotation group (n = 63), the entire cuff of the LMA ProSeal was placed in the patient's mouth without finger insertion and rotated 90° counter clockwise around the tongue. The LMA ProSeal was then advanced and rotated back until resistance was felt. The primary outcome was the insertion success rate at first attempt.

RESULTS

The success rate of insertion at first attempt was higher with the rotation technique than with the standard technique (97% vs 70%, respectively; P < 0.001) and the insertion time was shorter (16 ± 6 sec vs 30 ± 24 sec, respectively; P < 0.001). Mean blood pressure after LMA ProSeal insertion increased significantly in the control group (62 ± 12 to 69 ± 17 mmHg; P = 0.01), but not in the rotation group. The incidence of blood staining was lower in the rotation group than in the control group (10% vs 25%, respectively; P = 0.03), but the incidence of sore throat was not significantly different (24% vs 22%, respectively; P = 0.9).

CONCLUSIONS

The 90° rotation technique improves ease of insertion of the LMA ProSeal in children, and it decreases the risk of pharyngeal trauma. (ClinicalTrials.gov number, NCT01076725).

The Fastrach Intubating Laryngeal Mask Airway: an overview and update

PURPOSE

To provide an evidence-based overview and update on the use of the Fastrach Intubating Laryngeal Mask Airway (FT-LMA) when used within operative and non-operative settings.

PRINCIPAL FINDINGS

The FT-LMA is available in three sizes to provide ventilation and the ability to pass an endotracheal tube (ETT) into the trachea blindly, semi-blindly, or with indirect visualization for patients over 30 kg. The Chandy maneuver is recommended routinely; the first maneuver optimizes ventilation, and the second maneuver increases success at endotracheal intubation (ETI). The manufacturer's reinforced tube or a pre-warmed or reversed standard ETT may be utilized. Insertion and ventilation are successful in almost all patients. Blind ETI is highly successful; adjuncts are generally not necessary. The FT-LMA has a proven role in the airway management of anticipated difficult operating room (OR) intubations, unanticipated OR intubations, cervical spine injuries, and limited airway access situations. Literature in the pre-hospital and emergency department settings is limited but favourable. The FT-LMA has compared favourably with fibreoptic intubation, the LMA-Classic, the laryngeal tube, and the CobraPLA. Initially, the more expensive LMA CTrach appeared to be more successful, but overall it is not. The FT-LMA airway seal pressures are excellent; serious complications are uncommon, and the FT-LMA figures prominently in most difficult airway guidelines.

CONCLUSIONS

The FT-LMA has proven to be a useful difficult airway device both within and outside of the operating room. Effective ventilation is established in nearly all cases, and blind ETI is possible in the vast majority of cases if the optimal techniques described are used. Serious complications are uncommon.

Insertion of the ProSeal laryngeal mask airway is more successful with the 90 degrees rotation technique

PURPOSE

The 90 degrees rotation technique for inserting the ProSeal laryngeal mask airway (PLMA) in anesthetized paralyzed patients was compared with the index finger insertion technique.

METHODS

One hundred twenty Asian adult patients were randomly allocated to either a standard technique group or a rotation technique group. A PLMA size 4 was used for women and size 5 was used for men. In the standard technique group (n = 60), the PLMA was inserted using the index finger. In the rotation technique group (n = 60), the entire cuff of the PLMA was placed in the patient's mouth in a midline approach without finger insertion, rotated 90 degrees counter clockwise around the patient's tongue, advanced and then rotated back until resistance was felt. The primary outcome was success at first insertion. Secondary outcome measures were insertion time and complications.

RESULTS

The success rate at first insertion was greater for the rotation technique group than for the standard technique group (100% vs 83%, respectively; P = 0.003), and less time was required (11 +/- 3 sec vs 19 +/- 16 sec, respectively; P = 0.03). The incidence of postoperative sore throat was lower for the rotation technique group than for the standard technique group (12% vs 33%, respectively; P = 0.009), and blood staining on the PLMA was less (8% vs 40%, respectively; P < 0.001).

CONCLUSION

The 90 degrees rotation technique for inserting the PLMA is more successful than the standard index finger insertion technique. It is associated with fewer side effects, such as blood on the PLMA and sore throat, which suggests it causes less pharyngeal trauma.

Laryngeal mask airways--to inflate or to deflate after insertion?

BACKGROUND

Hyperinflation of the laryngeal mask airway (LMA) cuff is known to be a risk factor for airway morbidity and increased leakage around the LMA. While the manufacturers' recommendation is to inflate the cuff with the maximum recommended volumes and/or to adjust the cuff pressure to <60 cmH2O, cuff pressures below 40 cmH2O have been shown to be associated with a minimal rate of sore throat and minimal leakage. However, it remains to be determined whether inflation or deflation is needed to achieve favorable pressures. Therefore, we assessed the need for cuff-volume adjustment following insertion of the LMA unchanged straight from the sterile packaging in a prospective audit.

METHODS

One thousand children (0-16 years) undergoing elective surgery were consecutively included in this quality of care audit. After taking the LMA from its sterile packaging, the LMA cuff was emptied and the amount of air recorded. Then, the same amount of air was returned into the LMA, the LMA was inserted into the patient, and the cuff pressure was measured using a calibrated cuff manometer.

RESULTS

Following insertion of the LMA (without further inflation or deflation of the cuff), 20.5% of children had cuff pressures > or = 60 cmH2, while 55.7% had LMA cuff pressures <40 cmH2O. Cuff pressures were also significantly higher in size 1 LMAs (66.6% had cuff pressures > or = 60 cmH2O and 2% <40 cmH2O) compared with all other sizes (P < 0.05). Furthermore, cuff pressures in LMAs with a poly vinyl chloride (PVC) surface were higher compared to LMAs with a silicone surface (65.2% > or = 60 cmH2O and 9.3% <40 cmH2O vs 9% > or = 60 cmH2O and 67.6% <40 cmH2O, respectively).

CONCLUSIONS

This study demonstrates that LMAs, particularly when using small-sized LMAs or LMAs with a more rigid PVC surface, need to be deflated following insertion of the device rather than inflated to avoid cuff hyperinflation. Hence, cuff pressures should be measured routinely using a manometer to minimize potential pressure-related airway complications.

Insertion techniques of the laryngeal mask airway: a literature review

This article is based on a literature review comparing insertion techniques of the laryngeal mask airway (LMA). I will be looking at the manufacturer's recommended technique and identifying alternative methods, adapted for ease of use, patient comfort or individual circumstances. Risks associated with LMA use will be identified and examples given of research carried out to limit these risks.

Laryngeal mask airway insertion in children: comparison between rotational, lateral and standard technique

BACKGROUND

The purpose of the study was to compare the success and ease of insertion of three techniques of laryngeal mask airway (LMA) insertion; the standard Brain technique, a lateral technique with cuff partially inflated and a rotational technique with cuff partially inflated.

METHODS

One hundred and sixty-eight ASA I and II children aged 6 months to 6 years undergoing short elective surgical procedures lasting 40-60 min were included in the study. A standard anesthesia protocol was followed for all patients. Patients were randomly allocated into one of the three groups i.e. standard (S), rotational (R) and lateral (L). The primary outcome measure of the study was success rate at the first attempt using three techniques of LMA insertion. Secondary outcomes measures studied were overall success rate, time before successful LMA insertion, complications and maneuvers used to relieve airway obstruction.

RESULTS

Successful insertion at the first attempt was significantly higher in group R (96%) compared with group L (84%) and group S (80%) (P = 0.03). Overall success rate (i.e. successful insertion with two attempts) was 100% for group R, 93% for group L and 87% for group S (P = 0.03). Time for successful insertion was significantly lower in group R compared with group L and S (P < 0.001). The incidence of complications was lower in group R.

CONCLUSIONS

A rotational technique with partially inflated cuff is associated with the highest success rate of insertion and lowest incidence of complications and could be the technique of first choice for LMA insertion in pediatric patients.

Larynxmaske

Introduction of the laryngeal mask airway (LMA) has been a revolutionary development in airway management over the last decades. It was first used clinically in 1981 by A. Brain and has been widely used in Germany since 1990. Originally intended as a substitute for conventional mask respiration for short periods of general anaesthesia, the laryngeal mask is in the meantime used in many areas as an alternative to elective endotracheal intubation as well as an option for controlling difficult airways. This contribution provides an overview of the basics as well as practical aspects of LMA use, and discusses the possibilities and limitations of the laryngeal mask in daily practice.

Randomised, crossover comparison of the single-use SoftSeal?and the LMA Unique?laryngeal mask airways

We performed a randomised, crossover, single-blind trial among 168 patients, to compare the single-use SoftSeal and LMA Unique laryngeal mask airways in spontaneously breathing adults. Size-3 and -4 laryngeal mask airways, inserted by experienced anaesthetists, performed equivalently for successful first-time placement (148 (91%) vs 155 (96%) for the SoftSeal and LMA Unique, respectively). The SoftSeal was more often rated as difficult to insert (27 (17%) vs 4 (3%); p < 0.001) and was more likely to show evidence of mucosal trauma after the first insertion (14 (10%) vs 5 (4%); OR 1.3 (95% CI 1.3-11.3); p < 0.05). The fibreoptic view of the larynx was better through the SoftSeal (vocal cords not visible in 27 (17%) vs 44 (27%); p < 0.05) and it more frequently provided a ventilation seal at 20 cmH(2)O (93 (59%) vs 62 (39%); OR 2.15 (CI 1.44-3.21); p < 0.001). In contrast to the LMA Unique(trade mark), its cuff pressure did not increase during nitrous oxide anaesthesia (median (IQR [range]) decrease 3 (- 20-23 [-40-94]) cmH(2)O vs increase of 16 (-2-39 [-54-112]) cmH(2)O; p < 0.01). Both devices were equivalent for the success of first-time insertion and performed satisfactorily clinically. There were some performance differences, but either appears suitable for airway management in spontaneously breathing patients.

Fiberoptic assessment of laryngeal mask airway placement: Blind insertion versus direct visual epiglottoscopy

PURPOSE

The study aims to compare the frequency of ideal anatomic placement of the laryngeal mask airway (LMA) using the traditional blind insertion approach with one where placement was facilitated by the use of a laryngoscope (epiglottoscopy).

PATIENTS AND METHODS

A prospective comparison of 132 patients divided into 2 groups (38 with the blind technique and 94 with the direct technique) were evaluated with 2 airway assessment methods, Wilson and Mallampati. We also considered whether there was a relationship between these criteria and the successful placement into an ideal position. Other variables were considered, including breathing airflow dynamics, body size, and skill level of the anesthesia care provider. Five placement visual ordinals were used to grade the LMA position.

RESULTS

All of the patients studied except one had good to excellent breathing patterns after LMA placement. Statistically more patients who had ideal to nearly ideal placement position of the LMA were placed under direct epiglottoscopy than when placed by the classic blind technique. The position of the LMA was assessed by fiberoptic examination through an attachment between the LMA and the anesthetic circuit. Eighty-six of 94 patients (91.5%) in the direct visual placement group had ideal position compared with 16 of 38 (42%) in the blind placement group. Both groups had more successful placement than any other studies by comparison. Even several obese patients were successfully treated by either technique, and even the inexperienced anesthesia care provider could place the LMA with considerable accuracy.

CONCLUSION

One hundred thirty-one of 132 patients had no airway difficulties after LMA placement with either blind (classic) or direct visual epiglottoscopy (laryngoscopy). A fiberoptic scope proved to be a valuable tool to assess the results. When ideal placement is either highly desirable or necessary, the direct visual technique is considered to be a better choice for placement than the blind, classic method.

Fentanyl decreases propofol requirement for laryngeal mask airway insertion

BACKGROUND

Since fentanyl is a potent depressant of the upper airway reflex, preadministration of fentanyl may facilitate insertion of the laryngeal mask airway (LMA) using propofol. Accordingly, we tested the hypothesis that fentanyl pretreatment would reduce the dose of propofol required for the LMA insertion.

METHODS

Forty-one healthy patients without sedative premedication were randomly assigned to either fentanyl group, receiving fentanyl 2 microg kg-1 intravenously, or control group, receiving equal volumes of normal saline. Then, 3 ml of 2% lidocaine was given intravenously to alleviate pain associated with propofol administration. Thirty s after the fentanyl or saline injection, a predetermined dose of 1% propofol was given at a rate of 100 mg min-1. Insertion of the LMA was attempted 90 s after the completion of the propofol injection. The dose of propofol given to a particular patient was determined by the response of the preceding patient in that group to a higher or lower dose, using the up-and-down method. The first patient in each group received 2.5 mg kg-1 of propofol, while the step-size was 0.25 mg kg-1. Patients responses were assessed by a blinded observer.

RESULTS

ED50 and ED95 of propofol requirements were significantly less in the fentanyl group (0.82, 1.17 mg kg-1, respectively) than those in the control group (2.39, 2.62 mg kg-1, P < 0.001).

CONCLUSION

Our results indicate that preadministration of fentanyl 2 microg kg-1 decreases the propofol requirement for the LMA insertion.

The rotational technique with a partially inflated laryngeal mask airway improves the ease of insertion in children

BACKGROUND

This study compared the ease of insertion of the laryngeal mask airway (LMA) with a partially inflated cuff using the standard 'nonrotational' technique versus the rotational technique.

METHODS

One hundred and forty-five children undergoing anaesthesia using the LMA were randomly assigned to either method. The cuff was partially inflated in both groups. The ease of insertion was assessed by the time taken to complete the LMA insertion, the number of attempts before successful placement and the occurrence of complications.

RESULTS

The success rate of insertion at the first attempt was higher in the rotational technique group (99% versus 79%, P < 0.05). All patients in the rotational group had the mask inserted within two attempts. On the other hand, three patients had the mask inserted on the first attempt with the rotational technique after three unsuccessful attempts by an anaesthesiologist with the standard 'nonrotational' technique. Insertion technique made no difference on insertion time.

CONCLUSIONS

The rotational technique was associated with a higher success rate for insertion and a lower incidence of complications in children. Using the rotational technique with a partially inflated cuff could be the first-choice approach in paediatric patients.

Downfolding of the epiglottis induced by the laryngeal mask airway in children: a comparison between two insertion techniques

BACKGROUND

The purpose of this study was to compare the incidence of the downfolding of the epiglottis in children during insertion of the laryngeal mask airway (LMATM) using the standard technique and an alternative technique with the cuff partially inflated.

METHODS

Eighty paediatric patients were randomized into two groups and were anaesthetized using the LMA inserted with one of the two techniques.

RESULTS

There was no difference in the successful rate of insertion, fibreoptic findings and the lowest intraoperative SpO2 between the two groups.

CONCLUSIONS

The partially inflated cuff insertion technique does not increase the incidence of the downfolding of the epiglottis in children and would be an acceptable alternative to the standard technique.

The laryngeal mask airway: a comparison between two insertion techniques

The purpose of the study was to compare the ease of insertion of the laryngeal mask airway using the standard uninflated approach or with a fully inflated cuff. Two hundred consecutive patients undergoing anesthesia using a laryngeal mask airway were randomized to have the laryngeal mask inserted using either method. Successful insertion was judged primarily by the clinical function of the airway. The number of insertion attempts to achieve a satisfactory airway and whether an alternative technique was required for success were recorded. On removal of the laryngeal mask, a blind observer noted the presence or absence of blood. Just before leaving the recovery room, each patient was asked whether they had a sore throat. Insertion technique made no difference with regard to first attempt success. However, the presence of blood on the removed masks (P < 0.01) and sore throat (P < 0.01) were less frequent in the inflated cuff group. We conclude that the inflated cuff insertion technique is an acceptable alternative to the standard approach and has the advantage of reducing the incidence of minor pharyngeal mucosal trauma, as evidenced by mucosal bleeding and sore throat.

IMPLICATIONS

Insertion of the laryngeal mask airway with the cuff fully inflated is equally successful to the standard uninflated approach in experienced hands. The inflated technique was associated with less minor pharyngeal mucosal trauma and, consequently, a lower incidence of postoperative sore throat. This implies that the inflated technique would be acceptable to the general population of laryngeal mask users.

Optimal shape of the laryngeal mask cuff: the influence of three deflation techniques

A randomised, single-blinded, controlled trial was conducted to determine if a new laryngeal mask deflation tool offered any advantages over manual or free deflation. Ten laryngeal mask airways were tested and the deflation tool provided a significantly superior and more consistent shape than either hand manipulation or the free deflation, but did not offer any benefits in terms of residual volume. The deflator tool should encourage wider use of the standard recommended insertion technique. It can be used as a backup when manual deflation cannot provide the correct shape and may be useful for researchers studying laryngeal mask airway placement.