Spinal anaesthesia with Chloroprocaine HCl 1% for elective lower limb procedures of short duration: a prospective, randomised, observer-blind study in adult patients

Abstract

Background This prospective, randomised, observer-blinded study has been conducted in patients undergoing procedures of the lower extremities to evaluate the time to complete block resolution of 2-chloroprocaine 1% at three intrathecal doses (30, 40 and 50 mg). Methods After informed consent, we enrolled 45 male and female patients, aged 18–65 years, ASA score I-II, BMI 18–32 kg/m2, undergoing elective lower limb procedures lasting ≤40 min and with a requested dermatomeric level of sensory block ≥ T12. The patients were randomised in a 1:1:1 ratio to receive Chloroprocaine HCl 1% at one of the three different intrathecal doses (Group 30 = 30 mg, Group 40 = 40 mg or Group 50 = 50 mg). The progression and regression of both sensory and motor blocks were evaluated blindly. Urine and venous blood samples were collected for pharmacokinetic analysis. Results Times to regression of spinal blocks were 1.76 ± 0.35 h, 2.13 ± 0.46 h and 2.23 ± 0.38 h, in Group 30, 40 and 50 respectively: the 30 mg dose showed a significantly faster resolution of spinal block than the 40 mg (p = 0.034) and the 50 mg (p = 0.006). Time to readiness for surgery was significantly reduced with the dose of 50 mg when compared to dose of 30 mg (p = 0.0259). Conclusions The doses of 50 mg and 40 mg yielded a longer resolution of spinal block than the dose of 30 mg. Nevertheless, the dose of 30 mg resulted in a higher secondary failure rate. Trial registration Registration of clinical trial: clinicaltrials.gov (NCT02481505).

ED90 of spinal 2-chloroprocaine 1% in ambulatory knee arthroscopy up to 45 min: a randomized biased-coin- up-and-down sequential allocation trial

“…Our results differ from other dose finding studies with 2-chloroprocaine 1% reporting that a dose of 30 mg did not provide adequate anesthesia in lower limb surgery 5 6. There might be several explanations for this discrepancy.…”

“…The time to hospital discharge of 2.9 hours after intrathecal injection of 28 mg 2-chloroprocaine 1% in cohort II is consistent with a 30 mg dose described in literature 5 6 11 22. The offset time of motoric and sensory block (60 and 90 min, respectively), were not the dominant factors for discharge anymore.…”

“…Ghisi et al included lower limb surgeries up to 40 min. They also concluded that the 30 mg dose resulted in a higher secondary failure rate compared with 40 and 50 mg 5. Both studies included different types of lower limb surgery, while we focused on ultra-short knee arthroscopy.…”

“…The dose-finding design we used was different from the non-sequential design with preassigned doses used in previous dose-finding studies with 2-chloroprocaine 1% 5 6. An UDM allows measurement of the response at any point along the dose–response curve, making this a preferable design for establishing the minimum effective dose 13–15 17.…”

“…In recent years, preservative-free 2-chloroprocaine 1% has regained interest as short acting spinal anesthetic for lower limb surgery lasting up to 60 min 2. Several double-blind randomized controlled studies have demonstrated that, compared with other local anesthetics, the short duration of block of 2-chloroprocaine 1% favors a fast hospital discharge in outpatient anesthesia 3–11. Our previous study, in which we compared intrathecal prilocaine and 2-chloroprocaine 1% in ambulatory knee arthroscopy, inspired us to investigate the optimal dose of 2-chloroprocaine 1% for this indication.…”