Prophylactic Dexmedetomidine Versus Propofol For The Attenuation Of Circulatory And Airway Reflexes During Extubation

Objective:The aim of the study was to evaluate the effectiveness of dexmedetomidine and propofol when each is given separately prior to extubation,as prophylaxis against the prevailing stress response during emergence from anaesthesia.Concomitantly,whether a single pre-induction dose of dexmedetomdine(as control),was enough to provide smooth extubating conditions was explored.Methods:Sixty ASA ?-? patients scheduled to undergo thyroidectomy under TIVA were equally and randomly divided into 3 groups and allocated to receive in a double blind manner,either dexmedetomidine 0.5?g/kg(Dex),propofol 0.5mg/kg(Prop)or saline(Control)over five minutes before the anticipated end of surgery.All three groups received 1?g/kg dexmedetomidine pre-induction and each received the designated drug before extubation.Heart rate(HR),systolic,diastolic,mean arterial pressures,(SAP,DAP,MAP)and SpO2 were recorded before anaesthesia,before drug administration,at 3 and 5 minutes after drug infusion,just before extubation,immediately after extubation and thereafter at 3,5,10 and 15 minutes.Quality of extubation was evaluated on a 5-point scale and postoperative sedation on a 6-point scale.Patients were assessed for any events of laryngospasm,bronchospasm,desaturation,respiratory depression and undue sedation.The time from the discontinuation of maintenance drugs to complete emergence from anaesthesia was also recorded.Results:No significant differences were seen with regard to age,weight,gender.ASA status,surgical duration and SpO2 among the 3 groups.All three groups showed significant increases in heart rate at the time of extubation with the increase being minimal in propofol subjects(74.55±7.76)as compared to dex(76±7.59)and control(89.45±6.07).Arterial pressures notably systolic,diastolic and mean,(SAP,DAP,MAP)all increased significantly at extubation but the increase was least among dex patients.MAP at the time of extubation was as follows,Dex(99.05± 10.52),Prop(104.45±7.52)and Control(114.65±7.45).Dex was associated with the highest extubation quality with 85%of its subjects being assigned a score of 2 compared to 70%of prop and 45%of control.No desaturation was seen in any of the 3 groups.Ramsay Sedation Score taken at three endpoints showed significant difference at the time of extubation and 5 minutes post-extubation.The emergence time also demonstrated statistical significance with Dex being associated with the highest(29.2±3.09),followed by Prop with(27.75±2.43)and Control with(23.15±2.41).Conclusion:Dexmedetomidine provided better haemodynamic stability except for heart rate which was better controlled among propofol patients at the time of extubation.While dexmedetomidine was associated with a better extubation quality,propofol in turn provided faster recovery.This study also led to the conclusion that a single pre-induction dose of dexmedetomidine proved insufficient at maintaining haemodynamic stability and at enabling smooth airway conditions around the time of extubation.