Effects Of Different Loading Doses Of Dexmedetomidine On Heart Rate And Blood Pressure Of Critically Ill Patients

Introduction Dexmedetomidine is a highly selective new alpha 2-adrenoceptor agonist.Its most common adverse reactions are hypotension, nausea, bradycardia.We aimed to observe and compare the sedative effect of different loading doses of dexmedetomidine on heart rate(HR)? blood pressure(BP) and breath of critically ill patients in intensive care units(ICU).Methods Included in this study were patients who were retained in ICU and needed sedation between January and March 2014 by excluding patients with BP>200mm Hg and HR <60bpm or in a state of shock. The included patients were randomized to three groups(group A,B,C),and the three groups first received the designated doses of dexmedetomidine via an IV infusion pump for 10 min, and then maintained continuously at the same dose of dexmedetomidine. Ramsay score, HR, systolic blood pressure(SBP), diastolic blood pressure(DBP), Breath rate(BR) and Sp O2 were recorded before IV pump infusion and at 2, 4, 6, 10, 60, 120, 180 and 240 min after infusion.Results Patients in group A and B achieved the goal of sedation more quickly than those in group C(P<0.05). HR during 8-60 min after IV pump infusion of dexmedetomidine reduced more significantly in group A and B than that in group C(P<0.05). SBP at 10 min IV pump infusion in group A reduced more significantly than that in group B and C(P<0.05). There was no significant difference in the trend of SBP reduction between the three groups during the maintenance period.Conclusion The routine dose(0.4?g/kg·h) of DEX can provide an ideal effect of sedation in ICU patients. The recommended loading dose for a quicker sedation is 0.5?g/k·10min. High loading doses of DEX via IV pump infusion should be avoided in elderly patients, AECOPD patients and anemic patients, in whom combination medication can be considered when necessary.