The purpose of this study is to evaluate the effect of calcium chloride against residual neuromuscular blockade at the end of general anesthesia

During general anesthesia, neuromuscular blocking agent is administered to facilitate endotracheal intubation and the view of operative field. The neuromuscular blockade should be reversed at the end of anesthesia to recover spontaneous breathing of the patient.

Residual neuromuscular blockade (RNMB) is defined as train of-four ratio < 0.9. RNMB is a risk factor for postoperative pulmonary complication and increases postoperative mortality. Neostigmine is acetylcholinesterase inhibitor routinely used at the end of anesthesia to prevent RNMB. A meta-analysis, however, showed that 40 percent of patients who received intermediate-acting neuromuscular blocking agent during anesthesia showed RNMB in PACU.

Calcium triggers the release of acetylcholine from the motor nerve terminal and enhances excitation-contraction coupling in muscle. Increasing calcium concentrations decreased the sensitivity to dTc and pancuronium in an animal muscle-nerve model. The effect of calcium chloride on residual neuromuscular blockade is not studied yet.

The purpose of this study is to evaluate the effect of calcium chloride on residual neuromuscular blockade at the end of general anesthesia

Inclusion Criteria:

• 18-65 yr
• Body mass index 15.0-25.0 kg/m2
• American Society of Anesthesiologists physical status I-III
• Scheduled for elective surgery with an expected duration of more than 60 min under general anesthesia with endotracheal intubation

Exclusion Criteria:

• Suspected difficulty airway
• Bronchial asthma, chronic obstructive pulmonary disease
• Neuromuscular disease
• Hepatic or renal dysfunction.
• Taking medications that might influence the effect of neuromuscular blocking agents
• Allergy to the medication that used in this trial
• Pregnant, or breastfeeding state
• Suspected malignant hyperthermia
• Contraindication to the medication that used in this trial
• Hypercalcemia