Spreadsheets In Spreadsheets In Clinical Medicine Clinical Medicine

Grenville J. Croll & Raymond Grenville J. Croll & Raymond J. ButlerJ. Butler

EuSpRIG 2006, Cambridge, EuSpRIG 2006, Cambridge, UKUK

What We Know about What We Know about Spreadsheets Spreadsheets

Spreadsheets are error-proneSpreadsheets are error-prone Spreadsheets are not testedSpreadsheets are not tested Errors are difficult to findErrors are difficult to find Users are overconfidentUsers are overconfident Users are inconsistentUsers are inconsistent Users interpret information Users interpret information

differentlydifferently Backup and Archiving are Backup and Archiving are

overlookedoverlooked Spreadsheets are pervasiveSpreadsheets are pervasive

What We Know about What We Know about Medicine Medicine

Medical error is a major killerMedical error is a major killer 98,000 deaths per year in US 98,000 deaths per year in US 30,000 in UK30,000 in UK 7th largest cause of death7th largest cause of death Rate of non-fatal injuries is not Rate of non-fatal injuries is not

knownknown

Spreadsheets are used in Clinical Spreadsheets are used in Clinical MedicineMedicine

Spreadsheets in Clinical Spreadsheets in Clinical Medicine Medicine

Initial Google SearchesInitial Google Searches Spreadsheet + Oncology, Anesthesia, Spreadsheet + Oncology, Anesthesia,

Cardiac Cardiac etcetc

very many hitsvery many hits Search of PubMed DatabaseSearch of PubMed Database

>800 references, many clinical>800 references, many clinical Discovered Discovered www.medal.orgwww.medal.org - Institute - Institute

of Algorithmic Medicine - 8,000 of Algorithmic Medicine - 8,000 spreadsheetsspreadsheets

Numerous specialist sitesNumerous specialist sites

Spreadsheets in Clinical Spreadsheets in Clinical Medicine Medicine

Widely used for decision support Widely used for decision support Applied in diagnosis, dosage, Applied in diagnosis, dosage,

prescription, case management, prescription, case management, classification, statistical planning & classification, statistical planning & analysisanalysis

Home-grown by practitionersHome-grown by practitioners Used by medical device manufacturersUsed by medical device manufacturers Described in books & papers for re-Described in books & papers for re-

keyingkeying Many downloadable, modifiable templatesMany downloadable, modifiable templates

Controls on Software Controls on Software DevelopmentDevelopment

Drug development & trials Drug development & trials Onerous FDA software development Onerous FDA software development

requirements requirements Medical DevicesMedical Devices

Medical Device RegulationsMedical Device Regulations Apply to Medical Devices intended for Apply to Medical Devices intended for

salesale Clinical MedicineClinical Medicine

No regulation foundNo regulation found Medics free to develop & deploy for own Medics free to develop & deploy for own

useuse

Some Initial testingSome Initial testing Investigated the following modelsInvestigated the following models

Pediatric AnesthesiaPediatric Anesthesia Apache II – Risk of Cardiac Problems in Apache II – Risk of Cardiac Problems in

patients undergoing non-cardiac surgerypatients undergoing non-cardiac surgery Brodaty – to support a decision to assess Brodaty – to support a decision to assess

an elderly patient for masked depressionan elderly patient for masked depression Investigation restricted to Investigation restricted to

spreadsheet mechanics only as spreadsheet mechanics only as we are not medically qualifiedwe are not medically qualified But 15 pages of notesBut 15 pages of notes

Used HMRC SpACE methodologyUsed HMRC SpACE methodology

Pediatric AnesthesiaPediatric Anesthesia“…. here are two guides to help you in your anesthesia practice.  First is a Microsoft Excel spreadsheet titled ‘Pediatric Anesthesia Worksheet’. Use it to calculate medications and other parameters for pediatric patients”. 

Pediatric AnesthesiaPediatric Anesthesia

Pediatric AnesthesiaPediatric Anesthesia

Apache II - Chronic Apache II - Chronic HealthHealth

Apache II - Chronic Apache II - Chronic HealthHealth

Cardiac RisksCardiac Risks

Problems FoundProblems Found

Constants in formulasConstants in formulas Complex nested IF’sComplex nested IF’s Formulas with no dependentsFormulas with no dependents Poor or no embedded Poor or no embedded

documentationdocumentation Little/No data validationLittle/No data validation Some Mixed unitsSome Mixed units Weak cell protectionWeak cell protection

Embedded constantsEmbedded constants

Same risk as in finance/tax etc Same risk as in finance/tax etc domainsdomains

What happens if medical practice What happens if medical practice changes? changes?

What happens if manufacturers What happens if manufacturers reformulate drugs to require reformulate drugs to require different dosages?different dosages?

Table Lookups preferableTable Lookups preferable

Nested IF’sNested IF’s

e.g. Atropine dose calculation e.g. Atropine dose calculation (L7):(L7): =IF(E19*0.02>0.6,0.6,IF(E19*0.02<0=IF(E19*0.02>0.6,0.6,IF(E19*0.02<0

.1,0.1,E19*0.02)).1,0.1,E19*0.02)) E19 is “Bodyweight”E19 is “Bodyweight” The rest are embedded constants for The rest are embedded constants for

drug dosagedrug dosage Hard to follow Hard to follow Hard to updateHard to update Table Lookup preferableTable Lookup preferable

Other IssuesOther Issues

DocumentationDocumentation None/almost none embeddedNone/almost none embedded

Data ValidationData Validation None or inadequateNone or inadequate Forms tools, data validation Forms tools, data validation

essentialessential UnitsUnits

Milligrams / Micrograms appear in Milligrams / Micrograms appear in same column same column

NB Medication errors cause 7,000 NB Medication errors cause 7,000 annual deaths in USannual deaths in US

Pediatric Anesthesia Pediatric Anesthesia DocumentationDocumentation

Inherent RisksInherent Risks

Distribution channelsDistribution channels Large scale web enabled Large scale web enabled

distributiondistribution via Global Medical Literaturevia Global Medical Literature

Secondary “viral distribution”Secondary “viral distribution” Inability to recall sourceInability to recall source Spurious “stamp of approval” Spurious “stamp of approval” Spreadsheet may be changed Spreadsheet may be changed

somewhere in the chainsomewhere in the chain

ConclusionsConclusions

Initial indications are that same risks Initial indications are that same risks existexist

No specific clinical good practice for No specific clinical good practice for spreadsheet development & deploymentspreadsheet development & deployment

No evidence that this well studied No evidence that this well studied problem is known in the clinical domainproblem is known in the clinical domain

Opportunity for dialogue and Opportunity for dialogue and advancementadvancement

Obvious reasons for increased caution Obvious reasons for increased caution when one is involved in medical when one is involved in medical procedures!procedures!

DisclaimersDisclaimers

““The authors have exerted every effort to The authors have exerted every effort to ensure that the drug dosages set forth ensure that the drug dosages set forth are in accordance with current are in accordance with current recommendations at the time of recommendations at the time of publication. The user is urged to check publication. The user is urged to check the drug's package insert for any the drug's package insert for any changes in indications and dosages as changes in indications and dosages as well as for warnings and precautions. well as for warnings and precautions. The responsibility is ultimately that of The responsibility is ultimately that of the prescribing clinician”.the prescribing clinician”.

““Delegation of responsibility Delegation of responsibility is no barrier to the is no barrier to the

repeated perpetration of repeated perpetration of grave errorsgrave errors””

G.J.Croll & R.J. Butler, July 2006G.J.Croll & R.J. Butler, July 2006