Effects of sedation induced with dexmedetomidine versus propofol on intracranial pressure and cerebral oxygen metabolism in patients with permissive hypercapnia
10.3760/cma.j.issn.0254-1416.2011.04.001
- VernacularTitle:右美托咪啶与异丙酚镇静下允许性高碳酸血症患者颅内压及脑氧代谢的比较
- Author:
Liping WANG
;
Guozhong CHEN
- Publication Type:Journal Article
- Keywords:
Dexmedetomidine;
Propofol;
Intracranial pressure;
Brain;
Oxygen consumption;
Hypercapnia
- From:
Chinese Journal of Anesthesiology
2011;31(4):397-400
- CountryChina
- Language:Chinese
-
Abstract:
Objective To compare the effects of sedation induced with dexmedetomidine and propofol on intracranial pressure and cerebral oxygen metabolism in patients with permissive hypercapnia. Methods Twentyfour patients with acute respiratory distress syndrome (ARDS) were randomly divided into 2 groups ( n = 12 each) :dexmedetomidine group (group D) and propofol group (group P) . Their APACHE Ⅱ scores were 11-18. The patients were mechanically ventilated (VT 5-7 ml/kg, RR 12-17 bpm, PEEP 6-10 cm H2O, FiO2 40-60%). PaCO2 was maintained at 50-65 mm Hg. Radial artery was cannulated for direct BP monitoring and blood sampling. Right internal jugular vein was cannulated and the catheter was advanced cephalad until jugular bulb. Continuous infusion of dexmedetomidine was started at 0.5 μg· kg-1· h-1 and TCI of propofol was started at target plasma concentration (Cp) of 0.4 μg/ml. The infusion of both drugs was gradually increased until Ramsay score (1= fully awake, 6 =asleep, unresponsive to loud verbal stimulus) reached 3,4,5. Transcranial Doppler monitoring was used to determine cerebral blood flow velocity (CBFV), pulsatility index (PI) and resistance index (RI) before administration of dexmedetomidine and propofol (T0 ) and at 30 min after the 3 levels of sedation were reached (T1-3) . Meanwhile blood samples were taken from radial artery and jugular bulb for blood gas analyses. Cerebral O2 metabolic rate (CMRO2), cerebral A-V O2 content differences (Da-jvO2) and cerebral O2 extraction rate (CERO2) were calculated .ResultsCBFV, PI, RI and CMRO2 were significantly decreased at T1-3 as compared with the baseline values at T0 in both groups. CBFV was positively correlated with CMRO2 in both group D (r = 0.80) and group P ( r = 0.76) . CBFV, PI and RI were significantly lower at T1-3 in group D than in group P. There was no significant change in Da-jvO2 and CERO2 at T1-3 as compared with the baseline values at T0 in both groups. Conclusion At different sedation levels, dexmedetomidine results in lower intracranial pressure than propofol and maintains the balance between cerebral O2 supply and demand in patients with permissive hypercapnia.
