Abstract: AIM: To study the effect of intramuscularly injected methoxamine on blood pressure, pulse and cardiac output fluctuation induced by turiquet deflation in orthopaedic patients. METHODS: 60 patients scheduled for lower limb surgery with toumiquet were selected and randomly divided into two groups, each group with 30 patients. Patients in methoxamine group received intramuscular injection methoxamine 3 mg before the surgical skin saturation. Patients in control group received the same volume of nomal saline. In the following time points baseline level (T₀),before the surgical skin suturation (T₁), and 1 min(T₂), 3 min(T₃) and 5 min (T₄) after the toumiquet deflation ,the hemodynamic parameters systolic blood pressure(SBP),diastolic blood pressure(DBP) ,heart rate(HR) and cardiac output (CO) were measured. RESULTS: There was stable HR, blood pressure and cardiac output after the toumiquet deflation in methoxamine group. Whearas, a decreased BP and CO and faster HR were observed in control group. There were statistical significance on BP and HR between two groups.CONCLUSION: Intramuscularly injected methoxamine could effectively prevent cyclic changes induced by tourniquet deflation in patients with lower limb surgery, keep relatively stable haemodynamics.

Key words: Methoxamine, Tourniquet deflation, Hypotension, Cardiac output