Muscle Relaxants and Laryngeal Local Anesthetics for Laryngeal Mask Airway Insertion Decreasing Propofol in Elderly

The Impact of Using Muscle Relaxants and Laryngeal Local Anesthetics for Laryngeal Mask Airway (LMA) Insertion on Hemodynamics and Induction Anesthetics Dosage in Elderly

Laryngeal mask airway (LMA) is currently the most widely used supraglottic airway device with advantages of simple and fast placement, reduced anesthesia drug use, more stable hemodynamics, and less throat discomfort after anesthesia compared to endotracheal intubation. Some studies claimed the use of muscle relaxants or local anesthetics (sprays or lubricants containing local anesthetics) for the throat before LMA placement can reduce the dosage of induction agents and postoperative throat complications.

In modern society, more and more elderly people undergo elective surgery with the need of general anesthesia. However, they are the more vulnerable population with tendency of greater hemodynamic changes with more induction agent usage. Propofol is one of the most used induction agents which may lead to a drop in blood pressure. The objective of this study is to observe whether the dose of propofol and the changes in hemodynamics can be reduced by using muscle relaxants or laryngeal local anesthetics in elderly who receiving general anesthesia with LMA insertion.

Inclusion Criteria:

• American Society of Anesthesiologists (ASA) physical status I-III
• Age: over 65 years
• Elective orthopedic surgery undergo general anesthesia in supine position

Exclusion Criteria:

• Anticipated difficult airway (Mallampati score 3-4), limited mouth opening, intra-oral and pharyngeal pathology
• Risk of pulmonary aspiration of gastric contents (full stomach)
• Obesity (Body mass index > 35)
• Significant lung abnormalities (low lung compliance, high airway resistance, impaired oxygenation)
• Loosening teeth
• Allergic to Cisatracurium or Lidocaine
• Failure in successful LMA insertion after second attempts