Effect of therapeutic hypercapnia on balance between cerebral O2supply and demand in patients un-dergoing arthroscopic shoulder surgery in beach chair position / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the effect of therapeutic hypercapnia on the balance between cer-ebral O2supply and demand in the patients undergoing arthroscopic shoulder surgery in the beach chair posi-tion(BCP). Methods Forty-eight patients of both sexes, aged 21-64 yr, weighing 45-80 kg, of Ameri-can Society of Anesthesiologists physical statusⅠorⅡ, scheduled for elective arthroscopic shoulder surgery in the beach chair position, were divided into 2 groups(n=24 each)using a random number table control group(group C, end-tidal pressure of carbon dioxide 35-40 mmHg)and therapeutic hypercapnia group (group H, end-tidal pressure of carbon dioxide 45-50 mmHg). The regional cerebral oxygen saturation (rSO2)was recorded after induction and before BCP, immediately after BCP, at 3, 6, 9, 12, 15, 18, 21, 24, 27 and 30 min after BCP and at the end of surgery(T0-12). The occurrence of cerebral desaturation events, extubation time, duration of stay in postanesthesia care unit, development of nausea and vomiting and requirement for vasoactive drugs were recorded during surgery. Results Compared with the baseline at T0, the rSO2was significantly decreased at T1-12in group C and at T2-6in group H(P<005). The rSO2was significantly higher at T1-12, and the incidence of cerebral desaturation events was lower in group H than in group C(P<005). There was no significant difference between the two groups in the extubation time, dura-tion of stay in postanesthesia care unit, incidence of nausea and vomiting or requirement for vasoactive drugs (P>005). Conclusion Therapeutic hypercapnia can improve the balance between cerebral O2supply and demand in the patients undergoing arthroscopic shoulder surgery in the BCP.