Novel technique for placement of laryngeal mask airway in difficult pediatric airways.

BACKGROUND

The main responsibility of an anesthesiologist is to safely maintain an open airway and preserve sufficient gas exchange in the lungs. This role becomes more significant when managing children especially those with difficult airways (DA). In such cases, a quick appropriate action can decrease the related mortality and morbidity. Laryngeal mask airway (LMA) is a device used in cases with difficult airways. Its placement is much more difficult in children especially those with DA. There is a greater risk of malpositioning and its insertion with routine techniques is sometimes impossible. In this article, we introduce a new method for replacement of LMA in difficult pediatric airways (DPA).

METHODS

In this before and after, pre and post design clinical trial, we evaluated 30 children with congenital anomalies and difficult airways who were candidates for elective eye surgery (short term). A written consent was obtained from the parents or the legal guardians of those who met the inclusion criteria. Inhalation anesthesia was induced by sevoflurane. The patients had assisted spontaneous respiration. No muscle relaxant was administered. LMA was inserted using the classic method in the anesthesia depth of BIS = 35-40. After 2 unsuccessful attempts according to the criteria for adequate function of LMA, we tried placing the LMA using our innovated method after meeting the primary requirements and reaching the anesthesia depth of 35-40. In this method, the index finger of the left hand was placed on the tongue pushing it downwards (towards the floor of the mouth) when inserting the LMA. This way, we assisted LMA passing down the pharynx resulting in its adequate positioning. Criteria for adequate function of LMA in both classic and innovated insertion methods included monitoring of easy ventilation, no resistance during exhalation, adequate chest movement, no air leakage, optimal airway pressure, optimal lung compliance, level of oxygenation of arterial blood and level of CO2 at the end of exhalation. In case of presence of air leakage with bag pressure below 15 cm of water, lack of chest movement during inhalation, upper airway pressure over 20 cm of water, SPO2 lower than 90% and low compliance of the lung, LMA placement would be considered a failure. In such cases, LMA would be immediately extracted and the required depth of anesthesia would be reached using an oxygen mask and required inhalations. Complications occurring during the procedure and after LMA extraction would be recorded.

RESULTS

Our understudy population included 30 children in the age range of 1.5 months to 10 yrs (11 girls and 19 boys) who had clear DA criteria due to syndromes and severe congenital anomalies and were candidates for elective eye surgery. Duration of the operation was 30 to 60 minutes. In all 30 cases, LMA placement with the classic method was not successful after 2 attempts by an expert. LMA was successfully inserted for all cases by the same person using the innovated method after meeting the required criteria (BIS = 35-40). All ventilation indices were met and the operation was performed successfully with no complication.

CONCLUSIONS

There is always a risk of unsuccessful LMA placement in difficult pediatric airways using the classic method of insertion. The innovated method recommends pushing down the tongue by the index finger of the left hand. Considering the hypersensitivity of children to hypoxia and risk of unsuccessful LMA placement by the classic method, the innovated placement method is advised in children suffering from anomalies associated with macroglossia.