| Bucking reflex is a common clinical response under the general anesthesia tracheal extubation. Extubation and other operations during the suction may cause the patients cough. The chest, abdominal wall muscle contraction may further increase the chest and abdominal incision pain. Pulling moment can cause cough and more intense cardiovascular response. Therefore, it woud be ideal anesthesia to achieve "no cough extubation"during extubation without affecting the stability of the breathing cycle.As the latest agonist ofμopioid receptor, featuring with strong effect, rapid onset, quick metablism of, easy mastering of does, no accumulation and safety, Remifentanil shows special good performance in anesthetic maintenance and recovery.Method: The results of clinical experiments demonstrate that remifentanil can be used in extubation. It can control loop stability, reduce the choking suction and other stimulation which would affect body. However, the hemodynamic remifentanil woud pruduce dose dependent effect to central nervous and respiratory systerms. Lower concentration would not restrain the cardiovascular response effectively, while higer concentration may induce some side effects such as respiratory depression, bradycardia and excessive sedation et al. Therefore, it is quite important to discuss the effective concentration of remifentanil during extubation to inhibit cough reflex.There were 40 female cases with breast surgery under general anesthesia in our hospital, who met the inclusion criteria, were divided into two groups randomly, group A (control group) and group B (remifentanil group), 20 cases in each group.Patients with oxygen mask breathing (5 L/min) were performed induced general anesthesia by intravenous injection with midazolam (0.05 mg/kg), fentanyl (2~3μg /kg), atracurium (1~1.5 mg/kg) and etomidate (0.3mg/kg) in turn. Endotracheal tube was 7.0 size. Respiration was controlled with tidal volume 10 mL/kg and breathing rate 12/min. Propofol (4.0μg/mL) and remifentanil (3.0 ng/mL) was administrated by target-controlled infusion (TCI) during the operations. Atracurium should be administrated as required. And propofol should be stopped immediately when the operation was stopped. As the same time flurbiprofen should be administrated. And oral and airway secretions were cleared timely. Then neostigmine (2mg) and atropine (1mg) were administered by intravenous injection to inhibit residual action of muscle relaxant after regaining autonomous respiration. Then oral secretions were cleared, and aspiration of sputum was prohibited to avoid inducing bucking. When patients were conscious and their respiratory frequency is normal with tidal volume > 5 mL/kg and saturation of blood oxygen >95% when inhaling Oxygen 2 L/min, the endotracheal tubes would be removed. Remifentanil was stopped immediately in group A, while sequential method of TCI of remifentanil was administrated with a dose intervals of 0.1 ng/mL in group B, high dose was used if there was no bucking, otherwise low dose was used. And aspiration of sputum and extubation should be performed by a same doctor.Record the patients'heart rate, blood oxygen and blood pressure respectively before anesthesia, before and after unplugging endotracheal tube at 1, 3, 5, 10 minute. Record the ETCO2 before unplugging endotracheal tube and at 1, 3, 5, 10 minute after unplugging endotracheal tube. After stoping using propofol, record the time when patients are conscious and the time when they regain spontaneously breathing. Record the respiratory frequency before unplugging endotracheal tube and at 1, 3, 5, 10 minute after unplugging endotracheal tube. If the patients have the symptom of bucking while unplugging endotracheal tube, we have recorded the degree of bucking. And record the time of operation and anaesthesia, and infusion volume during the operation.Apply the SPSS14.0 to analysis the data. Measurement data is expessed by mean±standard deviation ( x±s), using t-test to compare, P<0.05 indicates that it has statistical significance. According the equation calculate the EC50 of remifentanil which can inhibit bucking reaction and its 95% confidence interval. Results: there is no significate difference in two groups at age, body weight, infusion volume, operation type, operation time and anaesthesia time.There is no significate difference at the time when patients are conscious and the time when patients regain spontaneously breathing.At the aspect of hemodynamics, before the anaesthesia the AB two group patients'heart rate and blood pressure is higher than that at the 135 minute after unplugging endotracheal tube, there is both no significant difference of the AB two groups patients'heart rate and blood pressure at the 10 minute after unplugging endotracheal tube.In group comparison, there is no significate difference of patients'heart rate and blood pressure before the anaesthesia. The patients'heart rate and blood pressure in group A is significantly higher than that in group B before unplugging endotracheal tube and at the 135 minute after unplugging endotracheal tube.At the time of unplugging endotracheal tube, the patients'blood oxygen in group A is little lower than that in group B, but there is no significant difference. There is no significant difference of the patients'respiratory rate between two groups at each time point.The occurrence number of bucking in group A is significantly more than that in group B. There in no adverse events during the operation of unplugging endotracheal tube. The EC50 of remifentanil which is used to inhibit bucking reflection during unplugging endotracheal tube is 0.73ng/ml, and its 95% confidence interval is 0.69~0.77 ng/ml.Conclusion: Sequential administration of remifentanil by TCI could control the fluctuate of hemodynamics and inhibit bucking reflex effectively induced by aspiration of sputum and extubation in conscious patients, the EC50 value is 0.73ng/ml, and the 95% confidence interval is 0.69~0.77ng/ml So it could improve security periextubate period. |
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