Height Adjusted Versus Standardized Dose of Bupivacaine for Spinal Anesthesia

Condition(s) studied

Investigational drug(s) / intervention(s)

standardized dose: intrathecal anesthesia with 10 mg of bupivacaine

adjusted dose: intrathecal anesthesia with 0.05 mg of bupivacaine par cm of patient's height

Study summary

General anesthesia during pregnancy is associated with several major risks including unanticipated difficult airway, pulmonary aspiration, and specific anesthetic effects on the newborn. Thus, intrathecal anesthesia is the technique of choice for cesarean section.

Nevertheless, the main side effect of intrathecal anesthesia is arterial hypotension which depend mainly on the dose of local anesthetic administered intrathecally.

To date there is no guidelines nor evidences whic help the anesthetist to precisely estimate the required dose. Most often a "standardized dose" of 8 to 10 mg of bupivacaine is administered. However, some data suggest that a lower dose may be administered resulting in less frequent arterial hypotension. Nevertheless, a well designed randomized study is lacking.

Eligibility

Primary outcome measure(s)

• rate of arterial hypotension — 4 hours since the start of intrathecal bupivacaine administration
  rate of arterial hypotension defined as a 20% or more decrease in systolic arterial pressure as compared with baseline systolic arterial pressure measured at 32 weeks

Trial sites (1)

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