Laryngeal mask airway for surfactant administration in neonates: a practical guide

[Faheemkhatri4]

Surfactant administration

Once proper placement of the LMA is achieved, administer surfactant in 2 ml aliquots. Administer the next aliquot once surfactant had cleared from the LMA, as determined subjectively by feel if using bag ventilation, SaO2 ≥ 94% and heart rate ≥100 beats per minute (bpm). If using PPV, surfactant has usually clears within 3-4 breaths. After administration of the last aliquot, continue PEEP and/or PPV until SaO2 ≥ 94% and heart rate ≥100 bmp. Remove the LMA (if using an LMA with an inflatable cuff, deflate cuff prior to removal).

Place infant back on NIV and adjust as needed. Verify proper OG/NG placement and readjust or replace if needed. Aspirate stomach contents, noting amount aspirated relative to amount administered (gastric aspirate is an imprecise indicator, as all of the surfactant may not have been aspirated and/or the gastric aspirate may represent gastric secretions or other medications in addition to surfactant, but relative amount does provide an estimate of potential leakage around the cuff). Return the infant to their normal position in the bed.

Physiologic stability

During the procedure, if SpO2 < 75% or heart rate <100 bpm, the procedure should be interrupted and PPV administered via the LMA or a mask until Sp02 > 94% and heart rate > 100 bpm. If the infant does not respond satisfactorily, appropriate therapy, which may include intubation and mechanical ventilation, should be instituted to achieve stable cardiopulmonary function.

Repeat dosing

If the LMA is positioned too high or too deep in the pharynx, the cuff will not form a seal and surfactant will leak into the esophagus. After the procedure, if there is a large percentage of the dose aspirated from the stomach and a lack of clinical response (i.e. lack of decrease in FiO2/ respiratory support requirement within the first minutes after instillation), the procedure may be repeated immediately through the LMA.

After the initial procedure, if additional doses of surfactant are deemed necessary by the clinical provider, additional doses may be given through the LMA at the appropriate time. Bubble CPAP Setup

Complications

While placement and surfactant administration through an LMA generally results in minimal fluctuation in physiologic parameters, bradycardia, hypoxia, hypotension and/or hypertension may occur and should be anticipated. The infant should be continuously monitored and personnel skilled in bag- mask ventilation and intubation should be present at the bedside.

Since the LMA rests in the posterior pharynx and surfactant is administered above the glottis (as compared to administration via an endotracheal tube which is delivered below the vocal cords), laryngospasm is a potential complication. In animal and human trials^8,10-14 and in clinical experience, laryngospasm has not be reported. However, because it is a theoretic risk, a muscle relaxant and personnel skilled in intubation should be readily available.

Provider training

In the Roberts trial⁸, providers had minimal or no prior experience placing an LMA. Training occurred by reviewing the procedure on a manikin. Successful placement of the LMA was achieved in < 35 seconds and on the first attempt in the majority of patients¹⁵. Providers stated they felt comfortable with the procedure after 2 experiences.