Laryngeal Mask Airway Protector™ for intubation and extubation in thyroid surgeries: A case report

Techniques of detecting recurrent laryngeal nerve palsy in patients undergoing thyroid surgery: Pearls and pitfalls

Though permanent vocal cord palsy consequent to recurrent laryngeal nerve (RLN) injury is rare following thyroidectomies, its consequences are grave enough for it to be the most feared complication postoperatively. Anesthesiologists and surgeons take various precautions to prevent its occurrence and employ various methods for its early detection. They include direct visualization of the nerve intraoperatively, use of intraoperative nerve monitoring, and post-extubation visualization of vocal cord mobility by use of direct or indirect methods. In the present narrative review, we aim to discuss the clinical evidence pertaining to the various methods adopted for the prevention and early detection of RLN palsy during thyroidectomy.

A randomised preliminary study to compare the performance of fibreoptic bronchoscope and laryngeal mask airway CTrach (LMA CTrach) for visualisation of laryngeal structures at the end of thyroidectomy

Background and Aims

Various methods have been used to check vocal cord movements as a routine before awakening the patient at the end of thyroidectomy to rule out recurrent laryngeal nerve (RLN) palsy; out of which, fibreoptic-assisted visualisation via laryngeal mask airway (LMA) being the most desirable.

Methods

Thirty patients of either sex, aged 18-65 years, American Society of Anaesthesiologists (ASA) grade I/II, scheduled for thyroidectomy under general anaesthesia (GA) were included and were randomised to receive either fibreoptic assisted (FB) or LMA CTrach-assisted (CT) visualisation of laryngeal structures at the end of thyroidectomy. The primary outcome was grade of view of laryngeal structures and secondary outcomes were time taken to achieve optimal view of laryngeal structures, ease of visualisation, hemodynamic parameters, and complications.

Results

In the fibreoptic group, we obtained comparable optimal laryngeal view i.e., grade 1 and 2 in all (100%) patients in comparison to 14 (93.33%) in LMA CTrach group. The "time taken to achieve the optimal view" was significantly lower in the CTrach group when compared to Fibreoptic group (220.67 ± 95.98 vis-a-vis 136.67 ± 68.98). The ease of visualisation of laryngeal structures was comparable (P = 0.713) and the baseline haemodynamic parameters were comparable between the 2 groups and at various designated intervals. In total, 6.66% and 26.66% patients in group FB and CT group, respectively, required manoeuvres. However, difference was statistically significant (P < 0.05).

Conclusion

Both Fibreoptic-assisted and LMA CTrach-assisted visualization of laryngeal structures in thyroidectomy are equally efficacious in terms of the optimal laryngeal view obtained and ease of visualisation. However, the time taken to achieve optimal laryngeal view was lesser with LMA CTrach.

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.