1. Lubrication
Apply lubricating oil under the ventilator; apply as little or no in the front as possible to avoid causing the patient to cough after insertion.
2. Induction of Anesthesia
Preparation before anesthesia and preoperative medication are the same as tracheal intubation. Muscle relaxants are not used when inserting the LMA. Anesthesia eliminates the gag reflex and relaxes the jaw, which can cause coughing or laryngospasm. Anesthesia can be induced by slowly injecting propofol followed by oxygen and denitrogenation, while inhaling N2O or volatile anesthetics. The combination of muscle relaxants has been reported to improve the success rate of LMA insertion. In addition, awake patients can tolerate LMA placement after satisfactory topical anesthesia.
3. Implantation of LMA
①Blind probe insertion method
After satisfactory general anesthesia or topical anesthesia, the head and neck are tilted back, the operator's left hand fixes the patient's head, and the right thumb and index finger hold the LMA ventilation tube with a pen, as close to the junction of the ventilation mask and ventilation tube as possible. The middle finger pushes the lower jaw down to open the patient's mouth, the ventilation hood opening faces forward, and is placed in the mouth on the inner surface of the upper incisor. Then place the index finger on the junction of the ventilation catheter and the ventilation mask, and push the LMA down along the upper palate. When the LMA reaches the posterior pharyngeal wall, the index finger can feel the change of direction.
And continue to push the LMA down as far as possible, generally the LMA can be placed in a suitable position. Pediatric patients are more appropriate with a reverse-inserted LNMA. Begin with the front of the mask facing the hard palate until the anterior end of the LMA reaches the posterior pharyngeal wall, rotate it 180°, and continue to advance into position.
②Laryngoscope insertion method
Holding the laryngoscope with the left hand, lift the patient's tongue up and hold the LMA with the left hand and insert it into the throat along the middle of the tongue.
