A trial of automated safety alerts for inpatient digoxin use with computerized physician order entry

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This article attempts to evaluate the utility of the introduction of a clinical decision support(CDS) algorithm, designed to “identify potential medication errors associated with digoxin”, to the CPOE component of the hospital EMR in a university teaching facility. The study design is a retrospective comparison of two patient cohorts each of 310 patients, identified by a computer search of the EMR and a manual review of timed clinician responses, which was the primary metric of interest. One cohort consisted of patients treated in the six months prior to the implementation of the digoxin CDS rule and the second cohort consisted of patients treated in the six months after implementation. The cohorts were not significantly different when compared for age, gender, total number of alerts or alerting situations, or electrolyte concentrations generating the alerts. The number of alerts for critical levels of hypokalemia(<3.0meq/L) was similar in both groups and not considered in the analyses because of separate reporting mechanisms for critical values at this institution.

The decision rule evaluated presents a real-time information only popup if digoxin is ordered and: K+ is < 3.5meq/L or Mg2+ is < 1.8meq/L without an order for electrolyte replacement, there is no recent recorded digoxin level in patients on digoxin, there is a digoxin level > 2.2mg/dL in the past 30 days, or the patient is concurrently on medications known to increase digoxin levels(eg – amiodarone, quinidine). The rule parameters identified in the paper are shown in the following table:

Table 1 j Alerting Situations and Expected Actions

(Alerting Situation)(Expected Clinician Action)

(K+ ,<3.5 mEq/L, patient receiving digoxin)(Order for K+ supplementation)

(Mg2+ ,<1.8 mEq/L, patient receiving digoxin)(Order for Mg2+ supplementation)

(No recent Mg2+ level, patient receiving digoxin)(Order for an Mg2+ level)

(No recent K+ level, patient receiving digoxin)(Order for a K+ level)

(No recent digoxin level, patient receiving digoxin currently and in the past)(Order for a digoxin level)

These parameters were chosen because they occurred with enough frequency and are associated with specific expected responses to allow evaluation. The authors also differentiate between synchronous alerts, those occurring at the time of the ordering process and asynchronous alerts, occurring later in response to abnormal results. Rates of expected compliance with alerts at 1 and 24 hours were tabulated for the 5 synchronous alerts listed in the table plus 2 asynchronous alerts, K+ < 3.5meq/L or Mg++ < 1.8meq/L.

The results of the study showed that prompts that recent K+, Mg++ or digoxin levels were not documented on the EMR at the time digoxin was ordered(synchronous activity) resulted in significantly improved rates of expected physician action – ordering of the respective level, compared with pre CDS action. Additionally, the two evaluated asynchronous alerts, low K+ or Mg++ levels generated on patients already on digoxin, also resulted in improved levels of physician compliance with expected actions, in this case the addition of K+ or Mg++ supplementation to the treatment regimen. Comparatively, synchronous notification of low electrolyte levels at the time of the initial digoxin order had no identifiable affect on the ordering of electrolyte supplementation in the two cohorts. The specific results are given as follows:

(Compliance 1 hour, Control %, Study %)(Compliance 24 hours, Control % Study %)

Alert Synchronous No Dig Level: (6%, 19%)(22%, 38%)

No K+ Level: (9%, 57%)(49%, 81%)

No Mg++ Level: (12%, 40%)(44%, 66%)

Low K+ Level: (6%, 23%)(47%, 56%(NS))

Low Mg++ Level: (22%, 39%(NS))(74%, 65%(NS))

Asynchronous Low K+ Level: (5%, 49%)(70%, 87%)

Low Mg++ Level: (6%, 35%)(77%, 93%)

NS = Not Significant

The author’s conclude that the results of this study support that CDS alerts improve the speed and magnitude of clinician responses. They cite the collective sevenfold increase in orders for electrolyte supplementation at one hour as a specific example. They also emphasize the need to present clinicians with all relevant information on the same visual interface used for medication ordering. They attribute the difference in response to synchronous and asynchronous reporting of low electrolyte levels to the nature of house-staff interaction with nursing staff and the mechanism by which the results are presented to the physician.

Comment It seems to me that the data can be looked at as representing diagnostic versus therapeutic responses. Prompts to order a test were much more effective at generating a response than prompts to change therapy. While it is true that clinician response, at least to the asynchronous prompts, was statistically improved after CDS implementation the ultimate difference at 24 hours between the groups was relatively small – 70% vs 87% in the low K+ group and 77% vs 93% in the low Mg++ group. In the comparative synchronously prompted groups, there was no statistically significant change at all. Clinician behavior is inherently conservative. The first rule of medicine is to not make things worse. I suspect that the reason there was not a more noticeable effect on physician ordering is because, since critical levels were eliminated from consideration, there was little sense of urgency to respond rapidly or, at all, to prompts, it being perceived to be much easier and perhaps much safer to just order another test. As noted previously, this particular CDS rule was presented as information only and did not require a response or provide for an automatic order for the expected action. My conclusion is that if the designers of rules for therapeutic interventions want to improve compliance, this would best be obtained by requiring physician action on the rule at time of presentation.

A Trial of Automated Safety Alerts for Inpatient Digoxin Use with Computerized Physician Order Entry

Reducing medication errors for hospitalized patients would lead to fewer adverse drug events and would therefore lower the cost of care, improve outcomes and increase the overall quality of care delivered. Digoxin is a drug used to treat heart failure and arrhythmias, and can reach toxic levels in patients when existing electrolyte levels are abnormal. This study aimed to evaluate the effectiveness of clinical decision support (CDS) in improving the safe use of digoxin. Over a period of six months, CDS alerts were delivered at the time of digoxin ordering and when a patient’s electrolyte levels were newly reported as low. The control data was taken from a chart review of the six months prior to CDS implementation. This study measured the speed and magnitude of clinician response.

The effectiveness of two alerts were evaluated. Synchronous alerts were informational alerts given to the clinician at the time of digoxin ordering. Alerts were invoked when digoxin was ordered for a patient without current digoxin or electrolyte levels available, or with low potassium or magnesium levels reported. Asynchronous alerts were invoked upon laboratory results indicating that a patient has newly abnormally low electrolyte levels. Asynchronous alerts were delivered via printouts and e-mail.

The results showed a great improvement in the study group’s response to synchronous alerts regarding unknown electrolyte and digoxin levels. Prior to CDS implementation, only 9% of clinicians had ordered potassium levels, and only 12% had ordered magnesium levels within the first hour after the digoxin order. With the alerts invoked, the respective numbers increased to 57% and 40%. At 24 hours, the control group orders were 49% for potassium and 44% for magnesium compared to the study group who showed additional increases to 81% and 66%.

When low levels of potassium or magnesium was reported at time of digoxin order through synchronous alerts, the alerts were not statistically improved.

When laboratory reports showed new abnormally low electrolyte levels, clinicians in the study group were quite responsive to the asynchronous alerts. They ordered magnesium supplements at a rate of 49% compared to a control rate of 5%. Study group clinicians ordered potassium supplements at a rate of 35% versus 6%.

Comments: This study was quite limited, as it seems alerts would be even more effective if it were easy to add on additional orders at the time of digoxin order, rather than just make a suggestion. Additionally, the CPOE should ensure clinicians are more aware of the clinical situation, including relevant electrolyte levels during digoxin ordering. If current levels have not been reported, then make it easy to order them along with the digoxin. This is less annoying than an alert after the fact.

The study did not measure the effectiveness of the increased orders on patient outcome. As it is the patient outcomes that clinicians want to improve, this needs to be studied further.