Impact of computerized physician order entry (CPOE) system on the outcome of critically ill adult patients: a before-after study

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    Impact of computerized physician order entry(CPOE) system on the outcome of critically illadult patients: a before-after studyHasan M Al-Dorzi1,2, Hani M Tamim1,2, Antoine Cherfan1, Mohamad A Hassan1, Saadi Taher1 andYaseen M Arabi1,2*


    Background: Computerized physician order entry (CPOE) systems are recommended to improve patient safety andoutcomes. However, their effectiveness has been questioned. Our objective was to evaluate the impact of CPOEimplementation on the outcome of critically ill patients.

    Methods: This was an observational before-after study carried out in a 21-bed medical and surgical intensive careunit (ICU) of a tertiary care center. It included all patients admitted to the ICU in the 24 months pre- and 12months post-CPOE (Misys) implementation. Data were extracted from a prospectively collected ICU database andincluded: demographics, Acute Physiology and Chronic Health Evaluation (APACHE) II score, admission diagnosisand comorbid conditions. Outcomes compared in different pre- and post-CPOE periods included: ICU and hospitalmortality, duration of mechanical ventilation, and ICU and hospital length of stay. These outcomes were alsocompared in selected high risk subgroups of patients (age 12-17 years, traumatic brain injury, admission diagnosisof sepsis and admission APACHE II > 23). Multivariate analysis was used to adjust for imbalances in baselinecharacteristics and selected clinically relevant variables.

    Results: There were 1638 and 898 patients admitted to the ICU in the specified pre- and post-CPOE periods,respectively (age = 52 22 vs. 52 21 years, p = 0.74; APACHE II = 24 9 vs. 24 10, p = 0.83). During theseperiods, there were no differences in ICU (adjusted odds ratio (aOR) 0.98, 95% confidence interval [CI] 0.7-1.3) andin hospital mortality (aOR 1.00, 95% CI 0.8-1.3). CPOE implementation was associated with similar duration ofmechanical ventilation and of stay in the ICU and hospital. There was no increased mortality or stay in the highrisk subgroups after CPOE implementation.

    Conclusions: The implementation of CPOE in an adult medical surgical ICU resulted in no improvement in patientoutcomes in the immediate phase and up to 12 months after implementation.

    Keywords: Intensive care unit, critical illness, CPOE, safety management, mortality, morbidity

    BackgroundComputerized Physician Order Entry (CPOE) is the pro-cess of entering medication orders and other physiciansinstructions electronically using a computer-based sys-tem to ensure standardized, legible and complete orders[1]. Its implementation has been recommended toimprove patient safety and outcomes [2,3] primarily byreducing medication errors [4] that usually arise from

    faulty prescriptions [5]. However, CPOE itself can leadto new types of errors [6-8], which may be detrimentalto patients. This may be more pronounced in criticallyill patients, a more vulnerable population due to theseverity of their illness, the complexity of interventionsdone and the diversity of equipments used in the inten-sive care unit (ICU). The evidence for the CPOE effec-tiveness in improving the outcomes of critically illpatients is scarce and remains controversial. Twobefore-after studies in pediatric ICUs showed no signifi-cant change in mortality after CPOE implementation

    * Correspondence: yaseenarabi@yahoo.com1King Abdulaziz Medical City, Riyadh, 11426, Saudi ArabiaFull list of author information is available at the end of the article

    Al-Dorzi et al. BMC Medical Informatics and Decision Making 2011, 11:71

    2011 Al-Dorzi et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative CommonsAttribution License (, which permits unrestricted use, distribution, and reproduction inany medium, provided the original work is properly cited.

  • [9,10]. Del Beccaro et al observed a statistically insignifi-cant decrease in mortality from 4.2% to 3.46% in the 13-month pre- and post-CPOE implementation [9]. Keeneet al found no change in mortality post-CPOE afteradjusting for all covariates (OR, 0.71; 95% CI, 0.32-1.57)[10]. On the other hand, Han and colleagues observedan increase in mortality from 2.8% to 6.6% during the 5-month period after the initiation of a CPOE system at apediatric hospital with a tertiary care ICU [11]. Litera-ture lacks information on the impact of CPOE imple-mentation on the outcomes of adult critically illpatients. The objective of our study, conducted as aquality improvement project, was to evaluate the out-comes of critically ill patients after CPOE implementa-tion in an adult ICU.

    MethodsSettingThe study was conducted at a 21-bed medical surgicalclosed ICU in a 900-bed teaching tertiary care hospital,King Abdulaziz Medical City-Riyadh, in Saudi Arabia. Itwas staffed by board certified intensivists 24 hours perdays, 7 days a week as described in a study from ourICU elsewhere [12] with rotating residents from differ-ent specialties. Nursing staff were multinational withpatient-to-nurse ratio of 1:1. The hospital was accreditedby Joint Commission International.

    Study DesignThe study was conducted as an observational before-after study. Data were extracted from a prospectivelycollected electronic ICU database. We included all con-secutive patients admitted to the adult ICU (age 12years) in the 24 months pre- and 12 months post-CPOEimplementation. We excluded patients with brain deathadmitted as potential organ donors. For patients whohad multiple admissions to the ICU within the samehospitalization, only the first admission was consideredin the analysis. The institutional review board of KingAbdulaziz Medical City approved the study and due toits observational nature, informed consent was waived.

    CPOE ImplementationBefore CPOE implementation, physicians wrote medica-tion orders on paper; nurses then faxed the orders tothe ICU satellite pharmacy; the pharmacist would screenthe order, make necessary adjustments after consultingwith the prescribing physician if needed, transcribe theorder and dispense the medication. The adult ICU wasthe first area in the hospital to implement CPOE. Otherhospital areas continued to use the traditional paper-based order writing during the study period. The usedsystem was a product from Misys, which was lateracquired by QuadraMed, and allowed medication and

    nonmedication orders as well as access to the patientschart, laboratory and radiological data. It included abasic real-time clinical decision support system so thatimportant interactions of prescribed medications, dosechecking and allergy notification appeared at the time ofprescription as pop-ups. In the year preceding CPOEimplementation, a multidisciplinary team prepared elec-tronic order sets and protocols. The team used theexisting paper-based order sets including ICU admissionorders, traumatic brain injury protocol and antimicrobialtherapy order set and converted them with some modi-fications into CPOE order sets. Some of these ordersets, such as the traumatic brain injury protocol, imple-mented since 2001, had been studied in our ICU andbeen shown to improve outcomes [13]. This was fol-lowed by training of ICU physicians, pharmacists andnurses on the use of CPOE functions. Following the GoLive on December 4, 2006, physicians directly enteredall medications and most nonmedication orders, such asspecific nursing instructions, requisition of laboratorytests and radiological examinations and consultations ofphysiotherapy and nutrition services, from any computerterminal inside or outside the unit. Pop-up alertsappeared on the screen and required verification beforeorder acceptance. Pharmacists screened electronic pre-scriptions and advised physicians in case of errors.Nurses checked their bedside computer terminals fornew and scheduled orders. Some orders, such as dietand blood transfusions, continued on papers. Technicalsupport and guidance were provided 24 hours a day, 7days a week for 2 weeks from the hospitals informationtechnology specialists, then as needed. To address theobserved difficulties and limitations and enhance theCPOE system, orders and order sets were revised uponagreement of physicians, nurses, clinical pharmacistsand medical informatics specialists. Such revisionsincluded transforming complex intravenous orders thatrequired more than 3 steps into single-step orders, opti-mizing doses and frequency of intravenous antibioticsand simplifying radiological and laboratory orders.

    Measurements and outcomesThe following data were extracted from the ICU data-base: age, gender, Acute Physiology and Chronic HealthEvaluation (APACHE) II score [14], source of admission(ward, emergency department, operating room andother hospital), main reason for ICU admission (as perAPACHE II definitions), cardiac arrest and sepsis as areason for admission, the presence of chronic health ill-ness (as defined by APACHE II system), admission Glas-gow Coma Scale, admission creatinine and InternationalNormalized Ratio (INR), requirement for vasopressorswithin the first 24 hours after admission and require-ment for mechanical ventilation during ICU stay. The

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  • primary outcome was ICU mortality. Secondary out-comes were: duration of mechanical ventilation, ICUand hospital length of stay and hospital mortality. Com-parisons were made for different time periods: one,three and 24 months before implementation comparedwith one, three and 12 months post-implementation.The reason for selecting these periods was to evaluateCPOE effect in the immediate and more extended per-iod of implementation and also to control possible sea-sonal variation of different outcomes. In addition, weevaluated the impact of CPOE in selected groups ofpatients, whose outcome was thought to be particularlyaffected by CPOE. These included: age 12-17 years sinceHan et al reported an increased mortality in the pedia-tric patients post-CPOE implementation [11], diagnosisof sepsis because outcomes of these patients can beaffected by timely interventions such as timely fluid andantimicrobial therapy [15] and traumatic brain injury assuch patients may benefit from protocolized manage-ment. Additionally, because patients with higher severityof illness were thought to be more vulnerable, we evalu-ated the effect of CPOE in patients with high APACHEII score, the median score which was 23.

    Statistical analysisSAS software (version 9.0; SAS Institute, Cary, NC)was used to analyze data. Continuous variables werereported as means with standard deviation and catego-rical variables as absolute and relative frequencies. TheChi-squared test was used to assess the differencesbetween categorical variables and the student t-testwas used for the analysis of differences in the meansof continuous variables. To examine the associationbetween CPOE implementation and various outcomes,we used stepwise multivariate logistic regression analy-sis. Independent variables entered in the model wereimportant factors that clinically affect outcomes andbaselines characteristics that were significantly differ-ent in the 24 month pre- and 12 months post-CPOEin addition to CPOE implementation status. The fol-lowing variables were entered in the model: age, gen-der, APACHE II, source of admission, non-operativetrauma and post-operative trauma as main reason foradmission, cardiac arrest as a reason for admission,chronic health illness (liver, cardiovascular and renal),creatinine, INR, vasopressors use, and mechanical ven-tilation. Results were reported as adjusted odds ratios(aOR) for categorical outcomes (ICU and hospital mor-tality) and beta (b) coefficient for continuous outcomes(duration of mechanical ventilation, length of stay inthe ICU and the hospital) with 95% confidence inter-vals (CI). This analysis was performed for the wholecohort and for the selected subgroups of patients. At a= 0.05, our study had an 80% power to detect a 4.8%

    decrease or a 5.2% increase in mortality after CPOEimplementation using the observed mortality (23.4%)in pre-CPOE implementation period and the numberof patients in the pre-CPOE (n = 1638) and post-CPOE (n = 898) periods. A P-value < 0.05 was consid-ered statistically significant.

    ResultsGeneral characteristics of all patientsIn the 24 months pre-CPOE implementation (Decem-ber 4, 2004 to December 3, 2006), 1638 patients wereadmitted to the ICU (13104 patient-days) compared to898 patients (7274 patient-days) in the 12 monthspost-CPOE implementation (December 4, 2006 toDecember 3, 2007). Table 1 describes the characteris-tics of patients admitted to the ICU in the followingperiods: 24 vs. 12 months, 12 vs. 12 months, 3 vs. 3months and 1 vs. 1 month pre- and post-CPOE imple-mentation. There were no significant differences inage, admission APACHE II score, admission GlasgowComa Scale, creatinine and INR in these pre- andpost-implementation periods. Compared to the 24months pre-CPOE implementation, the percentage offemale patients and postoperative trauma admissionswere higher in the following 12 months (39% vs. 35%,p = 0.04). Also there were significant imbalancesbetween the two groups in these variables: source ofadmission before ICU, chronic health illnesses and car-diac arrest as a reason for ICU admission. In addition,vasopressors (50% vs. 36%, p < 0.0001) and mechanicalventilation (77% vs. 73%, p = 0.004) were used morecommonly in the 24 months pre-CPOE compared to12 month post-CPOE implementation.

    Outcomes of patients pre- and post-CPOEimplementationTable 2 compares the outcomes of all patients in thecohort in relationship to CPOE implementation. Theimplementation of CPOE was not associated with a statis-tically significant change in ICU mortality when compar-ing the 24 months pre-CPOE to the 12 months post-CPOE (aOR 0.98, 95% CI 0.7-1.3), the 12 months pre-CPOE to the 12 months post-CPOE (aOR 0.96, 95% CI0.7-1.3), the 3 months pre-CPOE to the 3 months post-CPOE (aOR 0.83, 95% CI 0.5-1.5), the 1 month pre-CPOEto the 1 month post-CPOE implementation (aOR 1.17,95% CI 0.4-3.2). Similarly, CPOE implementation was notassociated with significant differences in hospital mortality,duration of mechanical ventilation and of length of stay inthe ICU and hospital in any of the four periods.

    Outcomes of patient subgroups according to CPOE statusTable 3 describes the outcomes of four subgroups ofpatients in the 24 months pre- and 12 months post-

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  • Table 1 Comparison of baseline characteristics of admissions to the intensive care unit pre- and post-computerized physician order entry (CPOE)implementation in four different periods: 24 months pre- vs. 12 months post-CPOE, 12 months pre- vs. 12 months p...


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