Intensive and Critical Care Nursing (2008) 24, 8—19

ORIGINAL ARTICLE

Implementing and assessing an evidence-basedelectrolyte dosing order form in the medical ICU�

Phillip Owena, Martin F. Monahanb, Robert MacLarena,∗

a School of Pharmacy, C238, Department of Clinical Pharmacy, University of Colorado at Denver andHealth Sciences Center, 4200 East Ninth Avenue, Denver, CO 80262, United Statesb Medical Intensive Care Unit, A021-230, University of Colorado Hospital, 4200 East Ninth Avenue,Denver, CO, United States

Accepted 14 April 2007

KEYWORDSElectrolyte;Potassium;Magnesium;Phosphorus;Critical care;Intensive care;Order form;Guideline

Summary The purpose of this study was to evaluate the efficacy, safety, andnursing acceptability of a nursing initiated, evidence-based order form to replacepotassium, magnesium, and phosphate in the MICU.Methods: This retrospective study compared patients receiving electrolyte replace-ment with the order form to matched historical control patients receiving traditionalelectrolyte replacement (no order form). The primary outcomes were absolutechange in serum concentrations and the proportion of doses achieving normal serumconcentrations. Other outcomes were adverse events as documented in the medicalrecord and nursing acceptability as assessed by survey.Results: The 2 groups (12 in each group) were similar. The order form and con-trol groups received 36 and 62 potassium doses, 14 and 48 magnesium doses, and34 and 13 phosphorus doses, respectively. Doses of all three electrolytes weresignificantly larger with the order form. Absolute changes in potassium, magne-sium, and phosphorus serum concentrations for the order form group and controlgroup were 0.36 ± 0.42 versus 0.11 ± 0.43 mmol/l (p < 0.01), 0.56 ± 0.69 versus0.13 ± 0.40 mequiv./l (p = 0.07), and 0.53 ± 0.82 versus 0.66 ± 0.83 mg/dl (p = 0.63),respectively. Normal serum concentrations achieved for each electrolyte replace-ment dose in the order form group and control group were 72% versus 18% (p < 0.001),86% versus 21% (p < 0.001), and 47% versus 62% (p = 0.57), respectively. No adverseevents occurred. The nursing survey showed satisfaction and comfort using the orderform.

Conclusions: The use of the order form provided greater efficiency for replacingpotassium and magnesium but not phosphorus without increasing the occurrence ofadverse events. The order form was well received by nursing staff.© 2007 Elsevier Ltd. All rights reserved.

� The results have been accepted as a poster presentation at the Society of Critical Care Medicine Annual Congress in February,2007 in Orlando, FL.

∗ Corresponding author. Tel.: +1 303 315 4772; fax: +1 303 315 4630.E-mail address: rob.maclaren@uchsc.edu (R. MacLaren).

0964-3397/$ — see front matter © 2007 Elsevier Ltd. All rights reserved.doi:10.1016/j.iccn.2007.04.006

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lectrolyte Replacement in the MICU

ntroduction

vidence-based medicine (EBM) is the critical eval-ation and clinical application of results fromigorously controlled clinical trials and systematiceviews. EBM incorporated with clinical expertisean be used to derive a decision on patient treat-ent (Akobeng, 2005; Cook et al., 1996,1997;cQueen, 2001). The process of implementing EBM

s often prohibited by the time required to dis-eminate information to health-care professionals,eluctancy of health-care professionals to acceptcientific data rather than anecdotal experience,nd lack of adherence to treatments by patientsGodlee, 1998; Green and Britten, 1998; Haynesnd Haines, 1998; McQueen, 2001). Many short-alls to implementation may be remedied by theevelopment of national or international consensusuidelines, or the use of institution specific pro-ocols that direct interventions (Browman, 2001;avis and Taylor-Vaisey, 1997; Eccles et al., 1998;rol et al., 1998; Haines and Donald, 1998; Vincentnd Berre, 1998; Woolf, 1999). Previous examplesf EBM, institution specific protocols involving thentensive care unit (ICU) include the managementf sedation and analgesia (Adam et al., 2006; Bairt al., 2000; Brook et al., 1999; De Jonghe et al.,005; Devlin et al., 1997; Gupta, 1999; Hadbavnynd Hoyt, 1993; MacLaren et al., 2000; Maloneyt al., 1997; Mascia et al., 2000; Micek et al.,004), neuromuscular blockade (DeBlock et al.,998; MacLaren et al., 2001), ventilator associatedneumonia (Cook et al., 1998; Dodek et al., 2004;uane et al., 2002), and stress ulcer prophylaxisMacLaren et al., 2006; Pitimana-aree et al., 1998).nly a single center report describes the devel-pment of an electrolyte replacement guidelineut it was implemented as a pocket card with nossessment of clinical efficacy or safety (MacLarent al., 1999). This article describes the develop-ent, implementation, and assessment of an EBM

rder form for replacing potassium, magnesium,nd phosphate in the medical ICU (MICU) and nurs-ng acceptability of the order form.

ackground

he University of Colorado Hospital is an aca-emic institution with a 373-bed complementncluding 48 ICU beds (medical, surgical, neuro-urgical, burn/trauma). The daily medical duties

n each ICU are provided by resident physiciansrom various disciplines, with precepting by a fel-ow physician. The care of patients in each ICU ishe responsibility of an attending physician repre-

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enting the disciplines of critical care/pulmonary,urgery, anesthesiology, and neurosurgery. Morn-ng multidisciplinary rounds have been performedor several years in each ICU, with representativesrom pharmacy, dietary, nursing, respiratory ther-py, and palliative care being present. Althoughharmacy and dietary have been heavily involvedith the care of patients, the dosing of replace-ent electrolytes has varied according to ICU

nd physician practices. Several problems haveeen evident, including incomplete repletion, mul-iple dosing, unnecessary measurements of serumlectrolyte concentrations, and excessive admin-stration of fluid. Historically, the independentdministration of potassium chloride and potas-ium phosphate for the treatment of hypokalemiand hypophosphatemia has contributed to hyper-alemic episodes. Nurses administering the elec-rolytes followed the recommendations for admin-stering intravenous medications from an onlinentravenous drug administration policy guidelinehat was applicable to the institution as a whole.nfortunately, this reference, which was createdo facilitate the safe administration of intravenousedications to all patients regardless of hospital

ocation, was perceived by many ICU health-are professionals as being representative of EBMractice standards within the ICU. However, theecommendations in this policy were not specifi-ally intended for the ICU, nor were they EBM.

Therefore, due to concerns about electrolyteeplacement, the multidisciplinary members of theritical Care Quality Assurance Committee decidedo develop an EBM order form for electrolyteeplacement, specifically potassium, magnesium,nd phosphate. An interdisciplinary subcommitteeonsisting of two critical care nurses, two clinicalCU pharmacists, and one pulmonologist developedhe dosing guidelines for the order form. The goalas to create an electrolyte order form that woulde applicable across all ICUs. Procedurally, therder form would allow critical care nurses to eval-ate and replete the electrolytes as needed, oncephysician ordered it as a standing order set in a

atient’s medical record.

ethods

rder form development

literature review using MEDLINE (for the period

anuary 1966 to October 2005) was conductedsing paired MeSH terms (Medical Subject Head-ngs) for keyword identification of potassium,agnesium, phosphate, electrolytes, critical care,

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intensive care, replacement, repletion, clinicalprotocols, surgery, hypokalemia, hypomagnesemia,and hypophosphatemia. All citations involvinghumans were retrieved and the bibliographiesreviewed to obtain pertinent articles not identifiedin the original search. The members of the sub-committee each informally assessed all the reviewarticles and studies for information relevant to thepatients admitted to the MICU (Alaniz and Rice,1993; Clark et al., 1995; Dickerson et al., 2001;Hamill et al., 1991; Hamill-Ruth and McGory, 1996;Hebert et al., 1997; Kraft et al., 2005; Kruse andCarlson, 1990; Kruse et al., 1994; MacLaren et al.,1999; Perreault et al., 1997; Rosen et al., 1995;Sacks et al., 1997; Taylor et al., 2004; Vannatta etal., 1981,1983). The members of the subcommitteemet to discuss the articles and to formulate roughdrafts of dosing guidelines for each electrolyteaccording to normal renal function. All membersof the Critical Care Quality Assurance Commit-tee reviewed the rough drafts, and discrepancies,concerns, and questions were discussed amongthe members. Some concerns arising as a resultof this review included ‘‘higher-than-expecteddoses’’ for intravenous magnesium and phosphatereplacement, absence of a guideline for calciumreplacement, omission of reasons not to use theorder form, the need for clarification of ‘‘normalrenal function’’, and controversy surrounding theapplication of these guidelines to all ICU patientsas practice standards. As a result, the order formwas modified to reduce the doses of magnesiumand phosphate. These modifications were done withthe knowledge that they deviated from EBM, butwould facilitate implementation of the order formas a practice standard. An EBM guideline for cal-cium replacement was not developed at this timeon the basis potassium, magnesium, and phosphateadministration posed a more immediate need formodification. The addition of clinical situationsthat stipulated when not to use the order form(diabetic ketoacidosis, arterial pH < 7.20 or > 7.60,and renal replacement therapy) and administra-tion information provided guidelines that could beused as practice standards for electrolyte replace-ment in all ICUs. The term ‘‘normal renal function’’was replaced by graduated dosing schemes forall electrolytes based on a calculated estimate ofglomerular filtration rate (GFR) using the Modifi-cation of Diet in Renal Disease (MDRD) equation.The MDRD GFR is automatically calculated and dis-played by the laboratory computer system for males

with serum creatinine concentrations ≥1.5 mg/dland females with serum creatinine ≥1.3 mg/dl.The committee decided that normal renal func-tion would be defined as a GFR > 50 ml/min/1.73 m2

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nd that renal insufficiency would be further sub-ivided into two groups, 25—50 ml/min/1.73 m2

moderate) and < 25 ml/min/1.73 m2 (severe). Theoses for these two subgroups were decreasedo avoid accumulation and subsequent suprather-peutic concentrations. The revised order formas redistributed to the Critical Care Qualityssurance Committee because it differed fromhe original form, and it was accepted withnly minor changes or clarification. The finalrder form gave doses for potassium, magne-ium, and phosphate as a function of MDRD GFRo achieve serum concentrations of 4.0 mmol/l,.0 mequiv./l, and 3.1 mg/dl, respectively, for adultatients in the ICU provided none of the follow-ng were present: diabetic ketoacidosis, arterialH < 7.20 or > 7.60, or renal replacement therapyAppendix A).

rder form implementation

embers of the Critical Care Quality Assuranceommittee suggested trialing the order form in theICU as an experimental pilot. Once the order formas properly evaluated for efficacy and safety, itas to be implemented in other ICUs. The pur-ose of this report is to describe the developmentnd implementation of the order form and providefficacy and safety results of the MICU trial. Thistudy was designed as an analysis of before andfter order form implementation. This report alsoescribes the results of a survey intended to assessurses’ acceptability of the order form. The investi-ational review board of the University of Coloradoealth Sciences Center approved the study prior toata collection. Because this project was deemed

practice improvement initiative, patient con-ent was not required and a Health Insuranceortability and Accountability Act waiver wasbtained.

The MICU nurses and staff were educated by onef the two clinical pharmacists or the MICU nurseducator for two weeks prior to the implementa-ion of the order form. Physician order entry is notvailable at the University of Colorado Hospital.nstead, orders are scanned so pharmacists are pro-ided an image of the order. The pharmacy orderntry process was streamlined by creating a tem-late for the order form, thus allowing the patient’sedication profile and medication administration

ecord to be efficiently updated. Implementationccurred when resident physicians were rotating to

rovide education during their ICU orientation pro-ram. Physicians were encouraged to use the orderorm and told to adhere to the doses provided inhe order form.

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ata collection

ata were collected for three months (November005—January 2006) after implementation. Medi-al records were audited only after discharge. Aatched historical control group was selected by

onducting drug utilization reports for the elec-rolytes in the MICU for the same 3-month period 1ear prior to implementing the order form. The con-rol group was matched to patients that receivedhe order form based on their diagnosis, Acute Phys-ologic and Chronic Health Evaluation II (APACHE II)core, GFR, and age.

Patients ≥ 18 years of age admitted to the MICUere eligible for inclusion. Patients were excluded

f they met one of the reasons for not using therder form. The following data, if available, wereollected: demographic information including age,ender, weight, height, primary diagnosis, sec-ndary diagnoses, past medical history; APACHE IIcore; ICU medications; nutritional intake includ-ng route, calories (kcal/(kg d)), protein (g/(kg d)),nd propofol dose; ventilatory support status; andaboratory parameters including serum concentra-ions of calcium, glucose, creatinine, blood ureaitrogen (BUN), total bilirubin, albumin, alanineminotransferase (ALT), and aspartate aminotrans-erase (AST). Data collected for comparativevaluations were serum electrolyte concentra-ions of potassium, magnesium, and phosphateefore and after each replacement dose; doses oflectrolyte replacement used; time to obtainingerum electrolyte concentrations after completionf the replacement dose; number of doses; andDRD GFR. The following adverse reactions weressessed: hyperkalemia, hypermagnesemia, hyper-hosphatemia, electrocardiogram (ECG) changes,rrhythmias, neuromuscular function, hypocal-emia, and adjusted calcium-phosphate product55.Nursing acceptability of the order form was

ssessed using a nine-point scale of five statements.he statements were designed to evaluate nurses’ttitudes regarding the safety, ease of use, satis-action, comfort, and patient applicability of therder form. Sixty-five nursing staff members wereducated and subsequently surveyed. Surveys wereistributed via e-mail at 6 and 12 weeks into therial period. Hardcopies were available at all timesn the MICU. All responses were directed to theurse educator.

ata analysis

he primary outcome assessed was the absolutehange in serum concentrations of each electrolyte

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ith the order form compared to the control group.econdary outcomes assessed were doses used,he number of doses of each electrolyte, the pro-ortion of replacement doses achieving normalerum concentrations, adverse events, and nurs-ng acceptability. Twenty replacement doses (10n each group) were needed for each electrolyteo demonstrate a 30% difference in the absolutehange in concentration between groups assum-ng standard deviations of 20% (Alaniz and Rice,993; Clark et al., 1995; Dickerson et al., 2001;amill et al., 1991; Hamill-Ruth and McGory, 1996;ebert et al., 1997; Kraft et al., 2005; Kruse andarlson, 1990; Kruse et al., 1994; MacLaren et al.,999; Perreault et al., 1997; Rosen et al., 1995;acks et al., 1997; Taylor et al., 2004; Vannattat al., 1981, 1983). Continuous data are reporteds mean ± S.D. unless otherwise specified. Com-arisons of continuous variables between groupssed unpaired Student’s t-test or Mann—Whitney-test. Comparisons of continuous variables withinroups used paired Student’s t-test or Wilcoxonigned Rank test. Nominal data were analyzed by2 test or Fisher’s exact test. All tests were twoailed, and a p-value of ≤ 0.05 was considered sig-ificant. Statistical analyses were performed withAS software, version 8.0 (SAS Institute, Cary,.C.). Survey results were assessed using theand/UCLA appropriateness method. Briefly, theedian response score was categorized according

o the nine-point scale so that a median response of—3 represented disagreement with the statement,—6 represented impartiality with the state-ent, and 6—9 represented agreement with the

tatement.

esults

wenty-four patients were identified as havinghe electrolyte replacement order form used dur-ng the 3-month period. Eight patients werexcluded because complete medical records werenavailable, three patients were excluded becauselectrolyte replacement was not administered (i.e.rdered but never needed), and one patientas excluded because renal replacement ther-py was initiated prior to electrolyte replacementdministration. Twelve matched patients weredentified from a cohort of 31 patients. There-ore, a total of 24 medical records (12 in eachroup) were audited resulting in 98 potassium

oses, 62 magnesium doses, and 47 phosphateoses.

Patient groups were similar in terms of demo-raphic variables (Table 1). Three patients in each

12 P. Owen et al.

Table 1 Patient demographic data and baseline characteristics

Control (n = 12) Order form (n = 12)

Age (years) 55.7 ± 14.04 49.2 ± 12.48Gender (M/F) 6/6 9/3APACHE II score 16.3 ± 5.03 15.8 ± 7.57Actual body weight (kg) 83 ± 30.81 84.3 ± 25.59Ideal body weight (kg) 64.83 ± 9.58 74.33 ± 14.27Mechanically ventilated n (%) 7 (58) 11 (92)

Primary diagnosis n (%)Cardiovascular 2 (17) 3 (25)Gastrointestinal 3 (25) 3 (25)Hepatic 1 (8) 1 (8)Neurologic 3 (25) 2 (17)Respiratory 2 (17) 2 (17)Sepsis 1 (8) 1 (8)

Medication n (%)Beta blockers 2 (17) 1 (8)Beta adrenergic agents 4 (33) 4 (33)Catecholamines 3 (25) 7 (58)Corticosteroids 6 (50) 5 (42)Insulin 3 (25) 7 (58)Loop diuretics 7 (58) 6 (50)Enteral nutrition 4 (33) 6 (50)Potassium sparing diuretics 2 (17) 2 (17)SMX/TMPa 1 (8) 2 (17)Potassium free MIVFsb 5 (42) 2 (17)

Routine laboratory dataGlucose (mg/dl) 123.5 ± 0.65 140.44 ± 55.96Serum creatinine (mg/dl) 1.23 ± 0.54 1.13 ± 0.70BUN (mg/dl) 29 ± 23.12 24.23 ± 24.79Calcium (mg/dl) 7.85 ± 0.65 7.85 ± 0.83Albumin (g/dl) 1.98 ± 0.76 2.60 ± 0.82AST (U/l) 96.83 ± 202.12 207.75 ± 409.7ALT (U/l) 40.78 ± 40.21 142.33 ± 237.52Total bilirubin (mg/dl) 1.40 ± 1.13 2.85 ± 2.68a SMX/TMP = sulfamethoxazole/trimethoprim.

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group had renal insufficiency. The mean GFR forthese six patients was 34 ± 8.1 ml/min/1.73 m2

and the mean serum creatinine concentrationwas 2 ± 0.3 mg/dl. Parenteral nutrition was notadministered. Mean time to follow-up labs forreplacement dose assessment were 7.92 ± 5.48 hfor the order form group and 8.09 ± 5.29 h for thecontrol group. Six (50%) order form patients andfour (33%) control patients were receiving enteralnutrition when electrolyte replacement wasordered. The daily caloric intake in these patientswas 11.94 ± 6.62 total kcal/kg and 11.75 ± 9.94

total kcal/kg, respectively. The daily proteinintake was 0.71 ± 0.26 and 0.56 ± 0.34 g/kg,respectively. Five order form patients andfour control patients were receiving propofol

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or 2.33 ± 2.53 and 5.15 ± 5.44 kcal/(kg day),espectively.

otassium (Table 2)

leven (92%) order form patients received 36eplacement doses of potassium and 12 (100%) con-rol patients received 62 replacement doses ofotassium. The mean intravenous dose was sig-ificantly higher with the order form resulting ingreater absolute mean increase in serum con-

entration when compared to the control group.

espite having a significantly lower mean serumotassium concentration before replacement, theroportion of doses achieving normal concentra-ions was approximately four-fold greater with the

Electrolyte Replacement in the MICU 13

Table 2 Potassium replacement results

Control (n = 12) Order form (n = 11) p-value

Total number of doses (iv/po) 62/0 34/2 0.12Mean intravenous dose (mequiv.) 32.7 ± 9.6 38.6 ± 7.6 0.006Concentration before replacement (mmol/l) 3.49 ± 0.27 3.32 ± 0.24 0.002Concentration after replacement (mmol/l) 3.58 ± 0.38 (p = 0.7

vs. before)3.68 ± 0.47(p < 0.001 vs.before)

0.28

Absolute concentration change (mmol/l) 0.11 ± 0.43 0.36 ± 0.42 0.003Doses therapeutic n (%) 11 (18) 26 (72) <0.001

Table 3 Magnesium replacement results

Control (n = 11) Order form (n = 7) p-value

Total number of doses (iv/po) 47/1 12/2 0.13Mean intravenous dose (g) 2.2 ± 0.7 3.8 ± 0.7 <0.001Concentration before replacement (mequiv./l) 1.63 ± 0.22 1.39 ± 0.19 0.004Concentration after replacement (mequiv./l) 1.76 ± 0.34 (p = 0.02

vs. before)1.96 ± 0.73(p = 0.009 vs.before)

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Absolute concentration change (mmol/l) 0.13 ± 0.40 0.56 ± 0.69 0.07(21)

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rder form. No adverse reactions were attributedo potassium replacement.

agnesium (Table 3)

even (58%) order form patients received 14eplacement doses of magnesium and 11 (92%)ontrol patients received 48 replacement dosesf magnesium. The mean intravenous dose withhe order form was nearly double the dose ofhe control group, resulting in a trend towards

greater absolute mean increase in serum con-entration with the order form. Despite having a

ignificantly lower mean serum magnesium con-entration before replacement, the proportion ofoses achieving normal concentrations was approx-mately four-fold greater with the order form. No

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Table 4 Phosphate replacement results

Control (n

Total number of doses (iv/po) 11/2Mean intravenous dose (mmol) 14.6 ± 4.7Concentration before replacement (mg/dl) 1.92 ± 0.3Concentration after replacement (mg/dl) 2.58 ± 0.9

(p = 0.014before)

Absolute concentration change (mmol/l) 0.66 ± 0.8Doses therapeutic n (%) 8 (62)

12 (86) <0.001

dverse reactions were attributed to magnesiumeplacement.

hosphate (Table 4)

leven (92%) order form patients received 34eplacement doses of phosphate and 8 (67%) controlatients received 13 replacement doses of phos-hate. The mean intravenous dose with the orderorm was double the dose of the control group buthe mean absolute increase in serum concentra-ions was similar between groups. The mean serumhosphate concentration before administration was

ignificantly lower in the control group. The propor-ion of doses achieving normal concentrations wasimilar between groups. No adverse reactions werettributed to phosphate replacement.

= 8) Order form (n = 11) p-value

27/7 0.628.8 ± 10.8 <0.001

0 2.25 ± 0.46 0.025vs.

2.78 ± 0.76(p < 0.001 vs.before)

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3 0.53 ± 0.82 0.6316 (47) 0.57

14 P. Owen et al.

Table 5 Nursing acceptability survey

Statement (responses = 36) Response rating (1—9 with 9indicating most agreement)

Median

1 2 3 4 5 6 7 8 9

(1) The electrolyte order form allows you tosafely care for patients

1 1 3 2 8 2 15 2 2 7

(2) The electrolyte order form is easy tounderstand and use

1 1 8 6 7 1 11 0 1 5

(3) The electrolyte order form improves yoursatisfaction with electrolyte management

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(4) You are comfortable administering theelectrolyte doses as prescribed in theorder form

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(5) The electrolyte order form may be usedin most patients you care for in the ICU

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Survey of nurses (Table 5)

Thirty-six (55%) surveys were returned. Nurses werein agreement that they were comfortable using theelectrolyte order form and that it was safe. Further-more, the nurses felt it could be applied to mostICU patients. Impartial responses were obtained forwhether nurses believed the order form was easyto understand and use; and whether the use of theorder form improved their satisfaction with elec-trolyte management.

Discussion

The primary findings of this retrospective evalu-ation indicate (1) the use of an EBM electrolytereplacement dosing order form effectively andsafely replenished potassium and magnesium serumconcentrations but not phosphate concentrationcompared to matched control group and (2) nurseswere comfortable using the order form. The authorsare unaware of other studies that have used theMDRD equation for the purpose of dosing medicinalagents in renal insufficiency. While few patients hadrenal insufficiency in our study, no adverse eventswere observed despite numerous doses suggestingthat the MDRD equation may be safely applied toelectrolyte replacement.

The effective replacement dose for potassiumand magnesium in critically ill patients variesbetween studies (Hamill et al., 1991; Hamill-Ruthand McGory, 1996; Hebert et al., 1997; Kruse andCarlson, 1990; Kruse et al., 1994; Sacks et al.,

1997). In general, however, these patients requirerelatively large doses to replenish intracellular con-centrations. Patients in our study being treatedwith the order form were more likely to attain

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ormal serum concentrations of potassium andagnesium. This is likely due to the administration

f larger doses with the order form compared to theontrol group. The use of larger doses also allowedor greater efficiency as the number of replace-ent doses needed was substantially reduced. Theean absolute change in serum potassium concen-

ration of 0.36 ± 0.42 mmol/l is consistent with theesults of other studies that showed changes of.25—1.1 mmol/l depending on the dose adminis-ered and baseline serum concentration (Hamill etl., 1991; Kruse and Carlson, 1990; Kruse et al.,994). Similarly, the mean absolute change in serumagnesium concentration of 0.56 ± 0.43 mequiv./l

chieved with the order form is consistent with theesults of other studies that demonstrated changesf 0.6—0.88 mequiv./l using slightly larger doseshan we administered (Hamill-Ruth and McGory,996; Hebert et al., 1997; Sacks et al., 1997).or both potassium and magnesium replacement,e deviated from EBM and chose to use slightly

ower doses in order to minimize the occurrencef adverse events and ensure clinical acceptabilityf the order form across all ICUs.

The results of phosphate replacement therapyere largely unexpected as only half the replace-ent doses with the order form attained normal

erum concentrations. Despite the doubling of theose compared with the control group, the meanbsolute increases in serum phosphate concen-rations were similar. The lack of efficacy withhe order form may be explained by deviationsn dosing from EBM that were required to ensurelinical acceptability. Other studies demonstrated

levations of serum phosphate concentrationsf 0.7—1.34 mg/dl compared to 0.53 ± 0.82 mg/dlbserved in our study with the order form (Alaniznd Rice, 1993; Clark et al., 1995; Dickerson et

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lectrolyte Replacement in the MICU

l., 2001; Perreault et al., 1997; Rosen et al.,995; Taylor et al., 2004; Vannatta et al., 1981,983). While many of these studies used meanoses similar to our order form group, the mostuccessful study of phosphate replacement usedoses based on patient weight adjusted for base-ine serum concentrations which resulted in dosesarger than what we used (Clark et al., 1995). Weeviated from this primary study of weight-basedhosphate replacement to simplify the orderingrocess and standardize doses in an effort to pre-ent adverse events associated with calculating andommunicating the dose. In addition, the process ofommunicating a calculated dose from the bedsideurse to the order entry pharmacist would reducefficiency. Of note, a recent study published afterhe implementation of our order form suggests thatffective replacement of serum phosphate concen-rations requires the administration of high doses,ven approaching 1 mmol/kg in cases of severeypophosphatemia (Brown et al., 2006). While theritical Care Quality Assurance Committee has dis-ussed altering the phosphate dosing scheme toequire higher doses, the consensus has been noto modify the order form because the present dosesepresented a deviation from our institutional stan-ard of practice as indicated by the doubling of theean dose compared to the control group.The authors are unaware of any studies that

ave used the MDRD equation to adjust dosing ofgents in critically ill patients with varying degreesf renal function. Historically, MDRD was not usedn patients with fluctuating renal function, or whoere critically ill (Garcia-Naveiro et al., 2005; Kuant al., 2005; Levey et al., 1999; Stevens et al.,006). Many physiologic and therapeutic aspectsssociated with critical illness may distort the MDRDesults. For example, the amount of fluid and typef fluid these patients receive could inadvertentlyffect weight and serum concentrations of albu-in and BUN. However, Hoste et al. compared theredictive ability of the five variable MDRD, theimplified MDRD, and a modified Cockcroft—Gaultquation to a measured urine creatinine clearancen critically ill transplant patients (Hoste et al.,005). The results showed modest but significantorrelation (p = 0.012) between the five variableDRD and the measured urinary creatinine clear-nce. One of the weaknesses in this study was thathe measured urinary creatinine collection was only1-hour collection and not a traditional 24 h col-

ection. Furthermore, the 28 patients in this study

ossessed stable serum creatinine concentrationshich may not be applicable to all ICU patients.nfortunately, our study had few patients withenal insufficiency, in part, because renal replace-

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15

ent therapy was a reason not to use the orderorm. In addition, patients with renal insufficiencyend not to have reduced serum concentrations ofhese three electrolytes because they are largelyenally eliminated. While additional evaluation ofhe order form in patients with renal insufficiencys warranted, we believe it is safe as no adversevents were observed.

Effective implementation of any order formequires prescribing practices to change whichepends on the opinions of recognized lead-rs, acceptance by those using the order form,eminders of prescribing changes, immediateeedback, and continuous education (Davis andaylor-Vaisey, 1997). The endorsement of the orderorm by the Critical Care Quality Assurance Com-ittee demonstrated the importance of electrolyte

eplacement to all ICU healthcare professionals.very effort was made to ensure the order formas user friendly and operationally efficient. The

urvey of bedside nurses was conducted to iden-ify issues with the order form. The results indicatehat nurses were generally satisfied with the orderorm and comfortable using it. As a result, the orderorm has been implemented in the burn/trauma andeurosurgery ICUs with plans for extension into theurgical ICU.

Possible limitations of this study include themall sample size and the limitations naturallynherent with retrospective descriptive studies. Wesed a matched control group to minimize theseimitations. However, eight order form patientsere excluded due to incomplete medical records,hich was likely the result of the chart auditccurring shortly after patients were discharged.he number of replacement doses of each elec-rolyte, however, met our sample size calculation.nfortunately, the limited sample size preventeddequate assessment of the order form for enteraleplacement and in patients with renal insuf-ciency. Accurate documentation of electrolyteeplacement, subsequent serum electrolyte con-entrations, and the occurrence of adverse eventsre difficult to extrapolate from a chart audit.here was no effort made to enforce the use ofhe order form as it was and remains optional.herefore, it is not possible to ascertain whetherelection bias of patients or physicians occurred.or example, perhaps the order form was preferen-ially not used in patients with renal insufficiencyecause physicians feared the possibility of induc-ng adverse events as a result of supranormal

oncentrations. The fact that enteral replacementas rarely used despite several patients receiv-

ng enteral nutrition suggests that even when therder form was used, bias existed toward intra-

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venous replacement. Therefore, compliance andadherence to the order form was not assessed.

In summary, the order form effectively and effi-ciently replaced potassium and magnesium but notphosphorus. No adverse events were observed andthe order form was well received by nursing staff.

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P. Owen et al.

ppendix A

inal version of the electrolyte replacement orderorm at the University of Colorado Hospital.

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