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Narrative review of neuraxial potassium chloride administration errors: clinical features, human factors, and prevention measures
  1. Santosh Patel1 and
  2. Franklin Dexter2
  1. 1Department of Anaesthesia, Tawam Hospital, Al Ain, UAE
  2. 2Department of Anesthesia, University of Iowa, Iowa City, Iowa, USA
  1. Correspondence to Dr Santosh Patel, Tawam Hospital, Al Ain 15258, UAE; skpatel{at}


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.

  • drug-related side effects and adverse reactions
  • neurologic manifestations
  • postoperative complications
  • neurotoxicity syndromes
  • anesthesia
  • conduction

Data availability statement

All data relevant to the study are included in the article or uploaded as supplementary information. Not applicable.

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Perioperative neuraxial drug administration errors can be catastrophic. Potassium chloride (KCl) is available in ampoules or vials or prepared infusion bags in several clinical locations as it is used to correct hypokalemia. On occasions, KCl ampoules or vials are used to prepare diluted KCl infusions by clinical staff. Local anesthetics or other dilutants (eg, normal saline (NS)) are also available in ampoules or vials or infusion bags in similar volumes to KCl. Medication administration errors involving high-risk medications such as KCl may occur via neuraxial route. In the presence of some human factors (eg, lack of awareness or inadequate supervision or substandard working environment).

Despite the practice of neuraxial anesthesia or analgesia for decades, drug administration errors via these routes are not well captured even in large audits or studies investigating complications related to regional anesthesia and acute or chronic pain medicine. One of the reasons may be that these route errors are not reported or not published or sometimes published in non-English and non-indexed medical journals. Therefore, true prevalence and harm severity of drug administration errors via neuraxial route remain unknown. KCl administration error has a potential to cause devastating consequences if administered via neuraxial route because normal potassium level is essential for any nerve conduction. In the current study, we aimed to review the literature to investigate the clinical characteristics and potential causes of KCl administration via epidural and intrathecal routes.


Medline and Google Scholar were searched through the end of March 2021 using the search protocol in the supplemental content. For example, the PubMed search phrases in the title and abstract included: (spinal anesthesia, subarachnoid injection, or epidural) and (potassium, KCl, or medication errors). Case reports also were found using the ‘related articles’ or ‘cited by’ links on Google scholar. There were no restrictions applied. For reports not written in English, we relied on Google Translate. As shown in the flowchart (online supplemental file), we included the 25 case reports of KCl drug errors via the intrathecal or epidural routes.

Supplemental material

For each error, patient characteristics, clinical location, clinical features, outcome, dose of KCl and its mode of administration, and neuraxial route were collated and entered in a standardized format. Investigations carried out including cerebrospinal fluid (CSF) potassium levels and radiological studies were recorded. Symptomatic and supportive therapeutic measures taken were also documented.

As a secondary analysis, Human Factors Analytical Classification System based on James Reason’s sliced Swiss cheese model was applied to analyze human factors. It describes latent or active failures in four layers: organizational influences, supervisory factors, preconditions for unsafe acts, and unsafe acts. The later include active skill-based and perceptual failures and violations, which can be routine (eg, failure to follow hospital policy) or exceptional. The preconditions for unsafe acts include substandard conditions (eg, adverse mental or physical states like inattention, fatigue, and hurry) or substandard practices of the operators (eg, lack of communication/coordination).

Whether barcode reading and/or use of non-Luer lock connectors could have possibly prevented these errors was evaluated. When a correctly prepared KCl infusion was misconnected to an epidural line, it was deemed that a connector technology may have prevented. When KCl was used to dilute other medications (eg, local anesthetic or opioid) or used as a sole medication (eg, in place of NS for loss of resistance during epidural procedure or in place of local anesthetic for spinal anesthesia), it was deemed that human double checking or human to computer checking (eg, barcode scan) may have prevented some errors.


Twenty-five case reports1–25 were identified that describe epidural or intrathecal1 9 22 administration of KCl in 28 adult patients (table 1). The details of each case are in the supplemental content. The 25 patients sustaining epidural KCl injection were levels of thoracic (nine patients)7 14–17 19 24 (7 two patients and 14 two patients), lumbar (13 patients)2 3 5 6 8 10–13 18 21 25 (8 two patients), and caudal (one patient)23 and two patients unlisted.4 20

Table 1

Characteristics of KCl errors by neuraxial route

Consequences were catastrophic. There were 22 of the 28 patients with paraplegia1–8 11–15 19 22–25 (7 two patients, 8 two patients, and 14 both patients) and 6 of those 22 with thoracic extension4 5 7 15 19 of the motor and sensory block (7 two patients). Eleven (of 28) patients underwent tracheal intubation and mechanical ventilation1–3 7 9 10 17 18 22 24 (7 two patients). Three patients died, two epidural3 21 and one intrathecal9 case, the latter including the mother’s baby.

A common (19 patients) sign of the neuraxial KCl administration was sympathetic hyperactivity manifesting as tachycardia and severe hypertension (table 1)1 4–7 9–11 14 15 17 18 21–25 (7 one patient). Severe lower limb and/or abdominal pain was reported in 19 patients. In some patients, pain was associated with paresthesia3 4 12 14 17 19 22 24 and muscle cramps.2 3 11 14 17 19 22 23 25 Diaphoresis5 7 14 16 22 23 and pruritus10 14 17 22–24 sometimes were present. Pulmonary edema,1 6 9 10 18 22 moderate to severe metabolic acidosis,7 14 17 arrhythmias,2 21 25 cardiomyopathy,18 24 and seizure2 were also reported. Respiratory depression,2 24 failure,17 18 24 or arrest3 and weak or absent reflexes4 11 13 22 23 25 were present in some patients.

KCl was administered via epidural catheter in wards or intensive care units for 17 patients2 4 7 10 12–17 19–21 24 25 (7 and 14 two patients each). KCl was used for dilution of local anesthetic and/or narcotic instead of NS for six patients2 7 10 13 21(7 two patients) A KCl syringe was swapped for local anesthetic.17 A correctly prepared KCl infusion was connected to the epidural for nine patients4 12 14–16 19 20 24 25 (7 one patient) The 95% exact binomial upper confidence limit for prevention by connector technology based on 9/28 (32%) would be 48%. There may, on the other hand, be more reports of this type among the cases published in the past 10 years (p=0.03).

Interventional pain procedures1 3 8 11 23 with bolus injection accounted for six patients receiving KCl administration (table 2) (8 two patients). The planned medication was inadvertently diluted with KCl for three patients in place of NS1 23 or distilled water.3 In three patients, KCl was used for loss of resistance in place of NS.8 11

Table 2

Epidural saline, cerebrospinal fluid (CSF) lavage and steroid therapy for potassium chloride (KCl) errors

Intraoperative errors were similar in mechanism, accounting for five patients.5 6 9 18 22 Planned epidural opioid5 or local anesthetic18 was diluted with KCl instead of NS. KCl was swapped with local anesthetic during the care of three patients, given by epidural6 or intrathecal9 22 bolus.

CSF potassium (normal value is 2.5–2.8 mmol/L) levels were measured in five patients following neuraxial KCl administration (one intrathecal1 and four epidural).3 7 21 Reported values (mmol/L) showed hyperkalemia: 27,1 30,3 4.3 (patient 1),7 >30 (patient 2)7, and >71.21 The latter measurement was postmortem.21

Intravenous (13 of 25 patients)2 5 7 10–12 15–17 19 24 25 and/or epidural (7 of 25 patients)2 7 8 11 17 25 steroid therapy was administered in some patients. There was inconsistency in steroid used, its route (epidural or intravenous or both routes) and doses (table 2). Epidural saline (8 of 25 patients) bolus4 15 24 25 or infusion12 16 17 19 therapy and spinal lavage (two of three patients)1 22 also were performed.

Table 3 lists human factors, as categorized by Human Factors Analysis and Classification System,26 and contributions to the errors. Lack of attention,10 14 16 infrequent monitoring,4 16 17 19 20 25 and working during nights4 16 17 21 were mentioned frequently. Nineteen of 28 errors including during interventional pain procedures, intraoperative period and in wards (when KCl was used to dilute local anesthetic or analgesic medications) may have been prevented by human double checking or human and device checking (eg, barcode scanning).

Table 3

Potential causes of neuraxial potassium chloride (KCl) drug errors: Human Factors Analysis and Classification System26


Our analysis provides insight into systemic factors contributing to inadvertent KCl administration, illustrates clinical aspects and highlights important prevention points. We found many of the KCl errors occurred while managing acute pain (15 of 28 patients) following surgery in wards (eg, general, high dependency, or intensive care) via epidural catheter in situ or during management of chronic pain in procedure room (6 of 28 patients). We expected errors would be due to KCl infusion bag connected to epidural catheter. However, that was so for only 9 of 28 cases. In this series, neuraxial KCl resulted in serious morbidity in majority of patients, permanent disabilities in two patients, and death in three patients (one with undelivered baby). To our knowledge, apart from tranexamic acid,27 no other drug has caused more iatrogenic short-term and long-term morbidity as much as KCl in regional analgesia practice during perioperative period.

Only 2% (75–80 mmol) of total body (approximately 4000 mmol) potassium is extracellular. Following neuraxial KCl administration, decreased intracellular/extracellular potassium ratio reduces transneuronal membrane potential causing a partial or complete depolarization of the cell membrane.14 28 If high potassium level is persistent and profound, as in most cases in this series, it causes the inactivation of the voltage-gated sodium channels, making the axons refractory to excitation.28 29 Consequences of prolonged depolarization30 (eg, intracellular calcium accumulation) and hyperosmolarity-related adverse effects31 (eg, vascular damage) might have also played a role in damaging effects of KCl.

Wide range of concentrations (0.2%–15%) and doses (139–3000 mg) were administered either as a bolus or as an infusion via lumbar or thoracic epidural route (table 1 and online supplemental table). Earlier reports suggested concentrations less than 6.45%4 and dose less than 1500 mg11 are associated with complete recovery from neurological effects. However, these correlations about concentration and dose have been refuted in more recent reports as patients recovered completely despite receiving higher concentration10 11 13 23 and doses12 14 23 via epidural space. From our analyzed reports, which occurred in wide range of clinical scenarios, it is not possible to elucidate concentration–effect or dose–response relationship following neuraxial KCl administration. Several known and unknown intrinsic (eg, age, type of neurones, epidural and intrathecal anatomy and physiological factors, and level of injection) and extrinsic (eg, amount of KCl, physicochemical properties of the solution, bolus vs infusion, and presence of other drugs) factors may determine ultimate duration and completeness of recovery.

Supplemental material

Another striking aspect of motor and sensory neurological consequences following neuraxial KCl is its similarity to clinical complications associated with neuraxial practice. This may lead to delay in suspicion and confirmation that KCl has been inadvertently administered. The inadequate block following intrathecal KCl was confused as a patchy block leading to readministration of KCl.22 Severe pain and paresthesia may be considered as a procedure-related trauma or as residual symptoms in chronic pain patients.8 Progressive motor and sensory block, in some cases associated with respiratory compromise, may simulate high or total spinal anesthesia 3 or back pain radiating to lower limb associated with motor and sensory block, and sphincter disturbance may lead to dilemma of epidural/spinal hematoma.11 Clinical features like sympathetic hyperactivity (tachycardia and hypertension), muscle spasms/clonic contractions, and diaphoresis may aid in suspecting KCl administration. The significance and correlation of the observed CSF hyperkalemia with patient clinical course remain unclear.1 3 7 21 MRI of the spine may not show any significant changes.6 19 22 24 Interestingly, in one patient,11 somatosensory evoked potentials (SSEP) recording led to suspicion of injection of the wrong substance and discovery of KCl vial.

Management of neuraxial KCl side effects is mainly symptomatic and supportive. Although steroid use was common, none of the reports quantified clinical neurological recovery benefit following intravenous and/or epidural steroid administration (table 2). It is difficult to demonstrate the benefits of epidural saline from our analysis because of large variation in KCl doses, presence of other drugs, different timings of administration relative to the incident and inconsistent volume (either bolus or infusion) administered, and so on (table 2). Authors who advocated its use suggest the beneficial effects of dilution of the drug with saline within epidural space, displacement of the drug from epidural to paravertebral space, and possibly increasing disposal via vascular route.32–34 However, NS flushing of epidural space following a large KCl amount administered in epidural space can result in further segmental spread of KCl with risks of quadriplegia, respiratory failure, and sympathetic hyperactivity.15 17 24 Therefore, its risk–benefits must be considered carefully.

For CSF lavage also, the optimal volume removal and ideal replacement fluid have not been well defined.22 Nevertheless, in the absence of other specific measures for intrathecal toxicity, early CSF lavage has a potential to reverse or limit the damage.1 22 In one patient,1 late (at least an hour) CSF lavage with peritoneal dialysis fluid decreased CSF potassium concentration from 27 to 2.2 mmol/L and was associated with unspecified early motor and sensory recovery. In another more recent case, Dias et al22 demonstrated regression of sensory block from T4 to T10 after CSF first lavage, which repeated after an hour. A pregnant woman (and her baby) died after receiving intrathecal 450 mg of potassium during elective lower segment caesarean section (LSCS). CSF lavage was not attempted in this case.

The incidences of perioperative medication errors are high, and there are many types of errors and contributing events.35 Many general and specific expert-based recommendations/opinions have been suggested involving organizational risk management policy (eg, lack of relevant medication policy) and safety culture, drug handling processes (eg, storage), pharmacy support, communication habits (eg, handover of care), workforce competency (eg, staff education and training), working environment, workstation structure, equipment design, use of technology, and so on. However, the relative importance of individual recommendation and its impact on prevention are limited by lack of high-quality, prospective medication safety studies.35 Neuraxial drug administration errors, although uncommon, are of high risk in nature, pose unique challenges, and require robust prevention strategies.27 36 37 Recently, Viscusi et al38 reviewed misconnection events involving either intravenous and/or neuraxial routes. They reported non-specific harm grading of only 5 KCl errors due to limited literature search. In contrast to their review, our analysis is comprehensive; includes all types of KCl errors; and details mechanism of errors, clinical circumstances (eg, perioperative phase), clinical sequelae, management options, human factors, and safety measures to prevent.

Between 1999 and 2002, safety organizations in the USA, the UK, and Canada issued safety alerts following fatal intravenous administration errors of KCl.39 The contributory factors identified were availability and storage of concentrated potassium ampoules/vials and unstandardized KCl solutions in the wards.40 Fatigue, night shift, hurry, multitasking, and inattention may cause incorrect visual perception of ampoules or vials or syringes or infusion bags or lines or pumps. For 19 of 28 patients in this series, irrespective of clinical location, prevention would depend on clinician and computer (eg, barcoding) or two clinicians checking labels both when the drugs are drawn up and immediately before injection. For only 9 of 25 cases, intravenous–epidural line confusion led to misconnections in this series. Therefore, our findings are limited by low level of evidence based on analysis of small number of reports. NRFit could prevent at most half the KCl incidents (upper confidence limit of 48%).

In conclusion, although rare, KCl administration errors via epidural or intrathecal route can be devastating. KCl drug administration errors predominantly occurred in wards in the postoperative period. Its clinical neurological adverse effects may be confused with other neuraxial complications. Connector technological devices are unlikely to prevent all errors as only few were due to intravenous–epidural catheter misconnections. To prevent neuraxial drug errors, human or technology use for double checking is required.

Data availability statement

All data relevant to the study are included in the article or uploaded as supplementary information. Not applicable.

Ethics statements



  • Presented at This report was previously presented, in part, at the virtual meeting of the American Society of Anesthesiologists, October 2020.

  • Contributors SP conceptualized and planned the literature search and data curation, prepared the original manuscript, and reviewed and edited the paper. FD helped with search strategy, performed the statistical analyses, and reviewed and edited the paper.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.