Extremely prolonged unilateral block (20 hours) with spinal ropivacaine used for cervical cerclage placement

Minimum effective dose of spinal ropivacaine with and without fentanyl for postpartum tubal ligation

BACKGROUND

Ropivacaine may be the ideal spinal anesthetic for postpartum tubal ligation due to its medium duration of action, low incidence of side effects and possibly reduced post-anesthetic care unit (PACU) stay.

METHODS

Two prospective up-down sequential allocation studies were performed using hyperbaric spinal ropivacaine via a combined spinal-epidural anesthetic technique for patients undergoing postpartum tubal ligation. The first study was performed using an initial dose of 12.5 mg hyperbaric ropivacaine, which was adjusted in testing intervals of 0.5 mg. The second study used an initial dose of 16 mg hyperbaric ropivacaine, a testing interval of 1.0mg, and a fixed dose of fentanyl 10 μg. The need to supplement the block with intravenous or epidural agents was defined as a failure. Failures were treated with epidural lidocaine.

RESULTS

The first and second studies recruited 24 and 17 patients, respectively. The median effective dose (ED50) for hyperbaric spinal ropivacaine was 16.4 mg (95% CI 13.7-19) with an ED95 estimate of 21.9 mg. The median effective dose of spinal ropivacaine with fentanyl 10 μg was 17.0 mg (95% CI 15.4-18.7) with an ED95 estimate of 21.3 mg. When data were combined, the overall ED50 for ropivacaine was 16.7 mg (95% CI 15.1-18.4) with an ED95 estimate of 22.5 mg (95% CI 16.3-28.8). A T8 block was not achieved in 4 patients receiving spinal ropivacaine alone, and 1 patient receiving spinal ropivacaine with fentanyl. The majority (82%) of patients who did not receive epidural local anesthetic supplementation had recovery of motor block within 60 min following PACU admission.

CONCLUSION

Spinal hyperbaric ropivacaine 22 mg with or without fentanyl 10 μg could be used for postpartum tubal ligation surgery.

A randomised comparison of the Portex Softseal laryngeal mask airway with the LMA-Unique during anaesthesia

We have compared the performance of the single use laryngeal airway devices Softseal and LMA-Unique in a randomised comparative trial in anaesthetised healthy patients who did not receive neuromuscular blockade. Primary outcome was success of airway placement. Secondary outcomes included manipulations and complications during use, ease of insertion, airway and fibreoptic assessment of airway positioning, and complications postoperatively. We planned to study 300 patients but interim analysis demonstrated the study should be stopped after 100 patients. During insertion the Softseal required more attempts for successful insertion (p = 0.041), more manipulations (p < 0.0001) and caused more complications (p = 0.048). Failure of placement occurred in five cases with the Softseal and none with the LMA-Unique (p = n/s). Two Softseal needed to be removed during maintenance because of airway obstruction, giving an overall failure rate of seven (p = 0.013). Serial tests of positioning favoured the LMA-Unique (p = 0.012). Ventilation was more successful in the LMA-Unique group but the difference was not significant (p = 0.051). Seal pressure was higher with the Softseal (26.5 vs. 20.5 cmH(2)O, p = 0.005). Fibreoptic view via the devices was not statistically significantly different. During maintenance of anaesthesia more complications arose with the Softseal (p = 0.03). Anaesthetist ratings of ease of insertion and overall usefulness favoured the LMA-Unique (p < 0.0001 and p = 0.024, respectively). After anaesthesia, sore throat occurred more frequently and was more severe in those patients anaesthetised with a Softseal both in recovery (p = 0.015) and at 24 h (p = 0.012). We conclude that the Softseal performs less well and causes more complications than the LMA-Unique.