Chloroprocaine vs prilocaine for spinal anaesthesia in day-case surgery: a double-blind randomized trial

In day-case surgery, spinal anaesthesia with both rapid onset and a short
duration of block is preferred. For this purpose, lidocaine has been the drug
of choice for decades but has been associated with an unacceptable number
(20-30%) of transient neurologic symptoms (TNSs). In recent years,
chloroprocaine (CP) and prilocaine (P) have gained interest as short-acting
spinal anaesthetics seemingly without the issue of urinary retention or TNSs.
So far, these drugs have not been compared as to whether one would be more
preferable than the other in an ambulant setting.

To investigate effectiveness of spinal chloroprocaine, and prilocaine in day
case surgery. The null hypothesis is that there is no significant intergroup
difference in complete recovery from motor blockade.

A double-blind randomized controlled trial

Patients receive intrathecally 40 mg plain chloroprocaine or 40 mg hyperbaric
prilocaine.

Physical examinations are the main burden for the patients participating in
this trial. Both sensory and the motor block are followed as usual but with a
higher frequency before, during and after the knee arthroscopy. Concerning the
sensory block, ice cubes are used at 2,4,6,8,10, 15, 20, 25 and 30 min, and
then at 15-min intervals until the sensory blockade had regressed tot dermatome
S2. Motor blockade is evaluated at 5, 10, 15, 20, 25, 30, 45, 60, 75 and 90 min
and then every 15 min until both legs can be fully elevated.
The urinary bladder will be examined by ultra-sound 30 min postoperative.
On the first and seventh post-operative days, the patients are interviewed by
telephone for any possible adverse events and their satisfaction as to their
spinal anaesthesia.
No blood samples will be taken.

There is no expected benefit for an individual trial participant. We hope that
our findings will benefit future patients in a similar situation.

The risk for an individual trial participant is expected to be very low because
the trial
drugs are licensed for the purpose we will use them for. Furthermore, spinal
anaesthesia with
prilocaine in knee arthroscopy is standard care in the Zaans Medical Centre.