Respiratory depression effect-site concentration of remifentanil used in combination with different target concentrations of propofol in patients undergoing neurosurgical surgery / 中华麻醉学杂志

ABSTRACT

Objective To determine the respiratory depression effect-site concentration (Ce) of remifentanil when used in combination with different target concentrations of propofol in patients undergoing neurosurgical surgery. Method Eighty patients aged 18-64 yr weighing 45-90 kg scheduled for elective neurosurgical surgery were randomly divided into 4 groups (n = 20 each): remifentanil group (group R), remifentanil combined with propefol 1, 1.5, 2 μg/ml group (group RP1, RP1.5, RP2). In group R, RP1, RP1.5 or RP2, the patients received propofol by TCI at target plasma concentration (Cp) of 0, 1, 1.5 or 2 μg/ml respectively, when the preset concentration was reached, received remifentanil via TCI at the initial target Cp of 2 ng/ml, and the concentration was then increased in the increment of 2 ng/ml at 3 min intervals until respiratory depression was achieved. Respiratory depression was defined as one of the following end points: muscle rigidity, RR<6 bpm, MV < 3 L/min, PETCO_2> 55 mm Hg, SpO_2 < 90% or apnea > 15 s. The Ce of remifentanil, amount of remifentanil used and side effects were recorded during respiratory depression. Result The respiratory depression Ce of remifentanil were (5.2±2.1), (3.2±1.0), (2.9 ±1.3) and (2.2±1.0) ng/ml in group R, RP1, RP1,5 and RP2 respectively. Compared with group R, the respiratory depression Ce of remifentanil were significantly decreased in group RP1, RP1.5 and RP2 (P<0.01). Compared with group RP1 and RP1.5, the respiratory depression Ce of remifentanil was significantly decreased in group RP2(P<0.01). There was no significant difference in respiratory depression Ce of remifentanil between group RP1 and RP1.5 (P > 0.05). Conclusion The respiratory depression Ce of remifentanil is (5.2±2.1) μg/ml in patients without sedation. The respiratory depression Ces of remifentanil are (3.2 ±1.0), (2.9 ± 1.3) and (2.2 ±1.0) ng/ml in patients under sedation with propofoi at target Cps of 1, 1.5, 2 μg/ml during neurosurgical surgery.