Clinical Study Of Preinjection Of Methoxamine For The Prevention Of Hypotesion In Elderly Femoral Head Replacement

Purpose: Before operating combined spinal-epidural anesthesia on senile patients with fracture of neck of femur, it observes the effect of hemodynamic changes in the caput femoris replacement surgery with intramuscular of different volume of methoxamine.Method: This task is assigned to anesthesia clinical research.There is 90 cases of senile patients with caput femoris replacement surgery who selecting a good time to operate and their weight is in range from 55 to 80 kg and age is from 65 to 80 years old and ASA grading is from II to III. Patients are randomly divided into A,B,C three groups, 30 cases in each group,and infect methoxamine into muscle before 5min(T0) of anesthesia,in which A group is intramuscular with 1mg,B group is intramuscular with 3mg,C group is intramuscular with 5mg..If patients’ blood pressure is stable,the reflexible decreased heart rate is less than 50 times/min after dosing,they can be cured with 0.25~0.5mg of atropine. It selects to use combined spinal-epidural anesthesia for each of them,routinely give 500 ml of sodium lactate ringer’s injection,500 ml of hydroxyethyl starch added with the standard of “patients’ weight(kg)×4、2、1×fasting time”. Observe MAP、HR、CO、SV hemodynamic changes of each group after dosing for 10min(T1),expansion of marrow injection of bone cement(T2) and finishing surgery(T3). Observe the volume of methoxamine on anesthesia and the influence of hemodynamic during operation.And it remains to see if necessary to add more volume.Result: Make anesthesia of patients in the first 3 groups with MAP、HR、CO、SV and there is no statistical difference(p>0.05).Comparing A group and B group,MAP、CO、SV of patients in A group all decrease in varying degrees after anesthesia taking effect in T1-T3, the compensatory character of HR is higher than that of B group with statistical difference(p<0.05);Comparing B group and C group,except HR,MAP、CO、SV of patients in B group decrease more obviously than that of C group after anesthesia taking effect in T1-T3.In T2,the MAP of B group decrease 10 mmHg less than that of C group while the MAP of C group does not decrease obviously in T2 by comparing with that in T0 with statistical difference(p<0.05);Comparing A group and C group,MAP、CO、SV of patients in A group decrease more obviously than that of C group while HR increases more obviously than that of C group with statistical difference(p<0.05) after anesthesia taking effect in T1-T3.Conclusion: While selecting a good time to operate caput femoris replacement surgery on senile patients,it injects 5mg of methoxamine into tibialis anterior for anesthesia and effectively prevents to appear hypotension with appropriate rehydration during operation such that it can keep patients’ haemodynamics stable.