Evaluation of cerebral perfusion pressure changes in laboring women: effects of epidural anesthesia

Objective To compare the effect of epidural anesthesia on cerebral perfusio n pressure in laboring women. Study design Maternal cerebral blood flow velocity was assessed in seven la boring patients with continuous epidural anesthesia and 15 without, using t ranscranial Doppler. Maternal cerebral blood flow velocity was assessed dur ing the first stage at the trough of a contraction, at the peak of a contra ction and at the second stage during pushing over the course of four contra ctions. Calculated estimated cerebral perfusion pressure: eCPP = V-mean/(V- mean-V-diastolic) x (mean BP - diastolic BP), where V is velocity and BP is blood pressure; modified from Aaslid and colleagues. An index of cerebrova scular resistance, the resistance area product, was calculated: RAP = mean BP/mean velocity. We calculated an index of cerebral blood flow (cerebral b lood flow index): CBF index = eCPP/RAP. Results In non-epidural patients, the eCPP fell significantly at the peak o f a contraction and during pushing. Cerebrovascular resistance, RAP, rose s ignificantly during the peak of a contraction, although cerebral blood flow did not change. In patients undergoing epidural anesthesia, the stages of labor had no significant effect on eCPP or RAP; however, these values were lower than those in patients without epidural anesthesia. Conclusions The epidural group had a lower eCPP and RAP and cerebral blood flow index compared to the non-epidural group. In the non-epidural group, t he mean arterial pressure was higher in all stages of labor with a trend to wards an increase in eCPP and cerebral blood flow index.