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

Evaluation of Four Techniques to Administer Laryngeal Mask Airway

Background

Laryngeal mask airway (LMA) plays a crucial role in the field of modern anesthesia. There are different techniques to administer LMA. Here we aimed to compare the four methods of standard, 90° rotation, 180° rotation, and thumb placement in LMA mast placement.

Materials and Methods

This is a clinical trial that was performed on 257 candidates of elective surgical operations requiring general anesthesia. All patients were categorized into four groups of LMA placement with index finger (standard method), mask placement with 90° rotation, 180° rotation method, and thumb finger group. We collected data regarding the success rates of LMA placement, the need for any manipulation when placing the mask, LMA placement time, failure of mask placement, presence of blood on the LMA, and laryngospasm and sore throats 1 hour after surgery in patients.

Results

The 90° rotation method had a significantly higher first attempt success rate than that in the other three methods (98.4%, P = 0.02). Total success rate in 90° rotation method was also significantly higher than the other techniques (100%, P < 0.001). The need for any manipulation when placing the mask (1.6%, P = 0.01), presence of blood on the LMA mask (1.6%, P = 0.33), and frequency of sore throats 1 hour after surgery (21.9%, P = 0.14) were also lower in 90° rotation method than that in the other methods.

Conclusion

The 90° rotation method had significantly higher success rate and lower failure rate regarding the mask placement compared to other three methods.

Comparison of the efficacy of Macintosh laryngoscope-guided insertion of I-gelTM with the conventional blind insertion technique – A randomised study

Background and Aims:

This study was designed to compare the efficacy of Macintosh laryngoscope-guided insertion of I-gel™ with the conventional blind insertion technique.

Methods:

A total of 156 adult patients scheduled to undergo elective surgery under general anaesthesia were included. All participants were randomly divided into two groups; I-gel™ was inserted with conventional blind and Macintosh laryngoscopic-guided technique in group A and B respectively. The primary objective of the study was to determine the incidence of optimal positioning in both the groups based on fibreoptic bronchoscope score of the glottic view. Oropharyngeal leak pressure, haemodynamic parameters and insertion characteristics were also compared. Categorical data were presented as ratio or percentage, continuous data were presented as mean ± standard deviation or median (95% confidence interval). The strength of association between insertion technique and the anatomical fit of the device was calculated by relative risk ratio.

Results:

Fibreoptic scores were significantly better in laryngoscope-guided insertion group when compared to the blind insertion group (P < 0.0001). The incidence of malposition was 3.85% in the laryngoscopic insertion group and 39.4% in the blind insertion (P < 0.0001). Oropharyngeal leak pressure was higher in laryngoscope-guided insertion group than in blind insertion group (26.89 ± 3.37 cm H₂O versus 24.42 ± 3.00 cm H₂O; P < 0.0001). Other insertion characteristics except time taken to insert the device were comparable in both groups.

Conclusion:

When compared to the standard blind insertion technique, laryngoscope-guided insertion of I-gel™ results in better alignment with the laryngeal inlet providing a proper anatomical fit and better airway seal pressure.

Lightwand-Guided Insertion of Flexible Reinforced Laryngeal Mask Airway: Comparison with Standard Digital Manipulation Insertion

Background

The flexibility of the long flexometallic tube makes insertion of the flexible reinforced laryngeal mask airway (f-LMA) difficult. We compared the usefulness of rigid lightwand-guided f-LMA insertion with standard digital manipulation.

Material/Methods

Fifty-four patients (aged 19–70 years) were randomly divided into a control group (digital manipulation technique) or the lightwand group (lightwand-guided insertion technique). The insertion profiles, oropharyngeal leak pressure (OLP), peak inspiratory pressure (PIP), expiratory tidal volume, and ventilatory score were measured in patients with neutral, extension, rotation, flexion, and re-neutral head-neck positions in turn.

Results

The success rate and ease of insertion did not differ between groups, but the insertion time was longer in the lightwand group. The fiberoptic laryngeal view was significantly better in the lightwand group than in the control group. However, the OLP, PIP, expiratory tidal volume, and ventilatory scores were not significantly different between groups according to head-neck positions. The extension posture was associated with a significant negative effect on ventilation, but ventilation returned to initial levels with the other postures.

Conclusions

Lightwand-guided f-LMA insertion showed a better fiberoptic laryngeal view than standard digital manipulation, but no improvement in the ventilatory state was observed due to position. Therefore, lightwand-guided insertion could facilitate correct placement of the f-LMA, but it has limited clinical usefulness.

Application of lower limb nerve block combined with slow induction of light general anesthesia and tracheal induction in elderly hip surgery

BACKGROUND

This study aims to evaluate the effectiveness and safety of lower limb nerve block combined with slow induction of light general anesthesia and tracheal intubation in hip surgery in the elderly.

METHODS

Thirty elderly patients who underwent hip surgery under the lower limb nerve block were randomly divided into 2 groups: slow induction of light general anesthesia and tracheal intubation group (group M), and laryngeal mask light general anesthesia group (group H). After undergoing total intravenous anesthesia without muscle relaxants, all patients received sciatic nerve, lumbar plexus, and paravertebral nerve blocks. The hemodynamic situations, dosage of anesthetics, time for awakening and extubation (or laryngeal mask removal), and incidence of respiratory adverse reactions in the induction period were recorded.

RESULTS

Compared with baseline levels, the difference in mean arterial pressure (MAP) value at each time point after intubation/laryngeal mask removal in both groups was not statistically significant (P > .05). Furthermore, the time for awakening and extubation/laryngeal mask removal, and anesthetic dosage were significantly decreased in group M, when compared with group H (P < .05). For the incidence of adverse reactions, the incidence of poor sealing and hypoxia was significantly lower in group M than in group H (P < .05), and the incidence of sore throat was significantly lower in group H than in group M (P < .05).

CONCLUSION

Lower limb nerve block combined with slow induction of light general anesthesia and tracheal intubation was associated with smaller anesthetic dosage, and shorter duration of anesthesia induction and extubation/laryngeal mask after surgery.

Supraglottic Airway Devices: the Search for the Best Insertion Technique or the Time to Change Our Point of View?

In the crowded world of supraglottic airway devices (SADs), many papers compare the easiness of insertion based on the different endpoints of an operator's satisfaction: first pass success, ventilation effectiveness, complications and morbidity. Proseal LMA^™ (Laryngeal Mask Airway, Teleflex Medical, Dublin, Ireland) has been extensively studied because on one hand it has a steeper learning curve and more complex insertion when compared with other SADs and on the other hand many alternative techniques are available to facilitate insertion. This research is part of a larger body of studies exploring the issue that some devices are more difficult to insert because of many features related to sizing, constructive material, airway conduit and cuff design, performance and last but not least experience. Nevertheless, the biggest question might be the search for a systematic categorization of insertion difficulty features and identification of criteria allowing the choice for the best device and consequently for the best insertion technique. Given that, as a result of many intrinsic characteristics of the device we are using, insertion might become the secondary issue to be considered only after we clearly identify what makes it difficult, and to be counterbalanced on the results we expect from the device, performance we can achieve and degree of airway protection it could grant. The aim of this narrative review is to consider which factors might affect or condition SAD insertion difficulty and to try identifying some criteria addressing physicians pertaining to the use of SADs in clinical practice.