Magnesium is More Efficient than Dexmedetomidine or Ketamine as a Prophylaxis against Bronchospasm during Emergence of Asthmatic Patients

Background: Anesthesiologists face multiple problems during management of asthmatic patients especially when endotracheal intubation is required. Bronchospasm is a risk due to the hypersensitive airway. A reliable technique for improving ETT tolerance while facilitating rapid and full emergence from general anesthesia would be desirable especially in patients with bronchial hyper-reactivity.Patients and Methods: This study was designed to compare the effect of magnesium, dexmedetomidine and ketamine in attenuating the response to the endotracheal tube during emergence From GA. Forty-five asthmatic patients were included in the study. Patients were randomly assigned to receive either MgSo4 20mg/kg, dexmedetomidine 0.5μg/kg or ketamine 0.5mg/kg during recovery from general anesthesia.The incidence of bronchospasm was recorded before administration of the study drugs, after administration of the study drugs and after extubation. Hemodynamics, the incidence of coughing and gagging and the time required for recovery were recorded.Results: Bronchospasm during emergence from general anesthesia was significantly lower in the magnesium group as compared to the other two groups. In the dexmedetomidine group, the time to recovery from GA was significantly shorter compared to the magnesium and ketamine groups. No significant difference between the studied groups as regard the incidence of coughing or gagging at extubation.Conclusion: Magnesium is more effective than dexmedetomidine and ketamine in reducing the incidence of bronchospasm in response to the endotracheal tube during recovery from general anesthesia in asthmatic patients although it is associated with some delay in the recovery time. The three drugs were comparable regarding the incidence of coughing and gagging.