Inadvertent intrathecal administration of potassium chloride during routine spinal anesthesia: case report

Narrative review of neuraxial potassium chloride administration errors: clinical features, human factors, and prevention measures

BACKGROUND

Administration of the wrong drug via the epidural or intrathecal route can cause devastating consequences. Because of the commonality of potassium replacement therapy coupled to its potential neurotoxic profile, we suspected that injuries related to this drug error would be present in the literature.

OBJECTIVES

We aimed to identify clinical characteristics associated with the inadvertent administration of potassium chloride (KCl) during neuraxial anesthesia. Our secondary objective was to identify human factors that may have been associated.

EVIDENCE REVIEW

Published reports of neuraxial administration of KCl in humans were searched using Medline and Google Scholar. Error reports in any language were included.

FINDINGS

25 case reports/series reported administration of KCl via epidural (25 patients) or intrathecal routes (three patients). There were six cases during interventional pain procedures, five cases in operating rooms and 17 in wards or intensive care units. Neuraxial KCl caused paraplegia in 22 patients. Mechanical ventilation was instituted in 11 of 28 patients. Three patients died. Epidural (eight patients) and spinal (two patients) lavage were performed to minimize consequences. A correctly prepared KCl infusion was connected to the epidural catheter for nine patients on wards (32%; 95% upper confidence limit: 48%) due to epidural-intravenous line confusion. Among the other 19 errors, KCl was confused with normal saline for 13 patients or local anesthetic in three patients. A wide range of concentrations and doses of KCl were administered. Variable use of intravenous steroid (13 patients) and epidural saline (eight patients) was found among patients who received epidural KCl. Human factors identified included incorrect visual perception, inadequate monitoring of infusions and substandard practice related to neuraxial anesthesia or analgesia.

CONCLUSIONS

KCl administration via epidural or intrathecal route has been reported to cause catastrophic consequences.

Inadvertent intrathecal injections and best practice management

The intrathecal space has become an important anatomic site for medical intervention not only in anesthesia practice, but also in many other medical specialties. Undesired/inadvertent intrathecal injections (UII) are generally rare. There is tremendous variation in reported inadvertent administrations via an intrathecal route in the literature, mainly as individual cases and very small case-series reports. This review aims to identify potential sources of UII, its clinical presentations, and appropriate management. The inadvertent injectants are classified as anesthetic agents and pain medicines, chemotherapeutics, radiological contrast agents, antibiotics and corticosteroids, and miscellaneous chemical agents such as tranexamic acid. The clinical effects of UII are dependent upon inadvertent injectant(s) and dose being administered intrathecally, and can range from no adverse effect to profound neurological consequences and/or death. Prompt cerebrospinal fluid (CSF) lavage and cardiopulmonary support seem to be the mainstay of treatment. If serious consequences are anticipated, CSF lavage could be lifesaving. This review additionally provides some options for comprehensive management and preventing strategies.

Spinal anesthesia revisited: toxicity of new and old drugs and compounds

PURPOSE OF REVIEW

Neural toxicity of substances injected into the intrathecal space has been a matter of debate since the introduction of spinal anesthesia in clinical practice. In recent years, new local anesthetics and adjuvants have been proposed for intrathecal use, and new techniques such as the use of ultrasound have been propagated. The present review summarizes recent clinical and experimental data on the neurotoxic effects of drugs and substances used for or in conjunction with spinal anesthesia.

RECENT FINDINGS

Chloroprocaine has been demonstrated to be associated with a lower risk of transient neurologic symptoms compared with lidocaine. However, despite extensive research, the issue of chloroprocaine or bisulfite neurotoxicity has not yet been resolved.Recent experimental data have identified a smaller neurotoxic potential for ropivacaine compared to levobupivacaine, procaine and bupivacaine. The addition of epinephrine has not been shown to increase lidocaine neurotoxicity. In-vivo experimental data suggest that lidocaine and bupivacaine neurotoxicity is not enhanced in diabetic patients.Furthermore, intrathecal introduction of aqueous ultrasound gel has been demonstrated to cause a distinct neuroinflammatory reaction. Finally, a large cohort study did not find the use of chlorhexidine gluconate for skin disinfection before neuraxial block to be associated with the risk of adhesive arachnoiditis.

SUMMARY

Clinical data suggest a high safety profile for intrathecal drugs and substances used for or in conjunction with spinal anesthesia. Recent experimental models for toxicity have provided further insight into the mechanisms and demonstrated possible, albeit clinically small differences in the relative neurotoxic potential of intrathecal drugs. This may contribute to a further increase in the safe use of spinal anesthesia in the clinical setting.

Feasibility of infusion pumps for continuous spinal administration of local anesthetics in post-operative pain therapy

BACKGROUND AND OBJECTIVES

For completion of perioperative care and for general ethical considerations, any intraoperatively used catheter technique should be utilizable for post-operative pain therapy. Continuous spinal anesthesia (CSA) is an established form of local anesthetic application. However, for its use in post-operative therapy, infusion pumps are required that are technically able to deliver low rates and are distinctive in design to avoid possible pump or medication swaps. Because of a lack of devices specifically designed for CSA, we investigated the potential deployability of infusion pumps for post-operative pain therapy via CSA microcatheters, which were originally designed and approved for different applications.

METHODS

The accuracy of infusion rates of three different pumps was measured in a liquor model environment. Furthermore, we investigated safety and user-friendliness by interviewing 30 anesthesiologists and 15 pain nurses.

RESULTS

Except for the first hour of infusion, all pumps provided comparable and adequate flow profiles. However, interviews revealed significant risk factors for all pumps in terms of swapping devices, lines or medications and misprogramming the units.

DISCUSSION

All pumps tested were technically able to deliver accurate flow rates; however, because the non-CSA-specific design involves the risk of medication overdosage and syringe swaps, none of the systems tested can be recommended for routine use in post-operative CSA, irrespective of the fact that it was an off-label application anyway. Therefore, to ensure patient safety, continuous spinal administration of local anesthetics via microcatheters is a questionable method of post-operative pain therapy as long as non-specific pumps are used.