Neuromodulation : journal of the International Neuromodulation Society
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Objective. To determine the stability of ziconotide-clonidine hydrochloride admixtures with and without morphine sulfate during simulated intrathecal infusion under laboratory conditions at 37°. Materials and Methods. Admixtures of ziconotide (25 µg/mL) and clonidine hydrochloride (2 mg/mL) with and without morphine sulfate (35 mg/mL) were stored in Medtronic SynchroMed® II pumps at 37°. Pumps were sampled immediately after filling and at four additional time points over the course of 28 (ziconotide-clonidine hydrochloride admixture) or 20 (ziconotide-clonidine hydrochloride-morphine sulfate admixture) days. ⋯ When compounded with both clonidine and morphine, ziconotide and clonidine concentrations declined; statistical evaluation indicated that the ziconotide concentration was 70% of initial after 20 days, and that clonidine would remain 90% stable for 42 days. Morphine was stable in the presence of ziconotide and clonidine. Conclusions. A ziconotide-clonidine admixture was 90% stable for 60 days (extrapolated), and a ziconotide-clonidine-morphine admixture was 70% stable for 20 days.
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Objective. To determine the stability of admixtures combining ziconotide with commercially formulated or powdered baclofen during simulated intrathecal infusion under laboratory conditions at 37°. Materials and Methods. Admixtures of ziconotide (25 µg/mL) with commercially formulated (1.5 mg/mL) or powdered (2.0 mg/mL) baclofen were stored in implantable intrathecal pumps at 37°. Drug concentrations were determined with high-performance liquid chromatography, and the length of time that the concentrations of both drugs remained ≥90% and ≥80% of initial (ie, the 90% and 80% stability, respectively) was estimated based on lower 95% confidence bounds obtained via linear regression. ⋯ In the commercially formulated baclofen admixture, the mean ziconotide concentration declined to 82.2% of initial in 30 days; the estimates for 90% and 80% stability were 12 and 29 days, respectively. In the powdered baclofen admixture, the mean ziconotide concentration declined to 87.4% of initial in 30 days; the estimates for 90% and 80% stability were 20 and 41 days, respectively. Conclusion. Ziconotide-baclofen admixtures were more stable when prepared using powdered baclofen rather than a commercial baclofen formulation.
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Purpose. The ethical challenges posed when a patient requests the discontinuation of a procedure during awake neurosurgeries are seldom discussed. We present such a case with a very brief ethics discussion. Case. A patient with idiopathic parkinsonism requested the discontinuation of a surgery in the middle of the implantation of bilateral deep brain stimulator electrodes. ⋯ Subsequently, the surgical team performed the steps necessary to safely halt the surgery. Conclusion. Even though the patient had the privilege of requesting a discontinuation, the surgeon had an obligation to keep the patient safe. Processes should be in place to assist decision-making about the continuation of awake surgery after such a patient request.