Retained intrathecal catheters/spinal drains: Case Discussion for the Week of June 22, 2009

Intrathecal catheters have been used in our instituition for the anesthetic management of hip fractures in the elderly and patients with significant medical issues where a general anesthetic would pose a considerable risk.
Spinal drains have been placed to aid in spinal cord protection during thoracic aortic aneurysmal surgery.
However, one of the dreaded complications [...]

A&A: The Efficacy of Skin Temperature for Block Assessment After Infraclavicular Brachial Plexus Block.

In summary, the Minville et al used an infrared “temp gun” to measure changes in skin temp following upper extremity nerve block. Increases in temperature correlated with successful nerve block with good PPV, sensitivity and specificity. NPV was 25% at 10min for a >1 degree C change in temperature. In failed blocks, no temperatures increased [...]

Finite-difference modeling of the anisotropic electric fields generated by stimulating needles used for catheter placement.

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Finite-difference modeling of the anisotropic electric fields generated by stimulating needles used for catheter placement.

IEEE Trans Biomed Eng. 2007 Jul;54(7):1186-90

Authors: Davis JC, Anderson NE, Ramirez JG, Enneking FK, Meisel MW

The use of peripheral nerve blocks to control pain is an increasing practice. Many techniques include the use of stimulating needles to locate the nerve of interest. Though success rates are generally high, difficulties still exist. In certain deeper nerve blocks, two needles of different geometries are used in the procedure. A smaller needle first locates a nerve bundle, and then is withdrawn in favor of a second, larger needle used for injection. The distinct geometries of these needles are shown to generate different electric field distributions, and these differences may be responsible for failures of the second needle to elicit nerve stimulation when placed in the same location as the first. A 3-D finite-difference method has been employed to numerically calculate the electric field distributions for a commercial set of stimulating needles.

PMID: 17605349 [PubMed - indexed for MEDLINE]

Infusate contamination in regional anesthesia: what every anesthesiologist should know.

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Infusate contamination in regional anesthesia: what every anesthesiologist should know.

Anesth Analg. 2008 Oct;107(4):1412-8

Authors: Head S, Enneking FK

Infection can be a devastating complication of regional anesthesia. Contaminated infusate as a cause of infection in neuraxial anesthesia or peripheral nerve blockade has rarely been reported in the literature. However, it may be an important source of morbidity, especially as increasing numbers of patients are being discharged with perineural catheters and portable pumps of local anesthetic, which may infuse for several days at home. Two important issues related to infusate contamination in regional anesthesia are that of “hang-time” and sterile compounding practices. Hang-time can be defined as the maximum length of time during which an admixture preparation (infusate) can be safely administered without risk of microbiological or chemical instability. In the United States, there are currently no national guidelines on the hang-times of regional anesthesia infusates. On the other hand, guidelines for the sterile compounding of infusions used in regional anesthesia are now established by United States Pharmacopeia and The National Formulary Chapter 797, entitled “Pharmaceutical Compounding, Sterile Preparations.” These guidelines have significant implications for the anesthesiologist. In this review, we examined the available literature regarding contaminated infusate as a cause of infection in regional anesthesia, to discuss strategies for the prevention of such contamination including the appropriate hang-time for infusates, and to discuss the implications of United States Pharmacopeia and The National Formulary Chapter 797 for anesthesiologists.

PMID: 18806061 [PubMed - indexed for MEDLINE]