Surveillance: Retrospective versusprospective

Sandra Blake, R.N., B.S.N.,Esther Cheatle, M.D.,Betty Mack, R.N.,Springfield. III

A survey was undertaken to determine if a retrospective review of charts fornosocomial infections could be as accurate as a prospective review of charts. Theretrospective review was done by medical record technicians using criteriaestablished by the Infection Control Committee and the medical staff. The infectioncontrol nurse reviewed the data collected by the Medical Records Department beforethe monthly report was completed. Surveillance was done prospectively by theinfection control nurse and an R.N. helper. The study was carried out on twonursing units. The infection control team used the same criteria as the medicalrecord technicians. At the end of the 4-month study period, infections found bymedical record technicians were compared to those found by the infection controlteam. The Medical Records Department identified more nosocomial infections thandid the nurse team. It was concluded that the Medical Records Department can doan accurate review of charts for nosocomial infection and that their report isreliable to show basic trends. The infection control nurse is then able to spend hertime on special studies and investigations as well as employee education. (A.\1 JINfECT CONTROL 8:75, 1980.)

0196-6553/80:030075+04$004010 © 1980 Assoc Pract. Infect Control

Surveillance for nosocomial infections is rec­ognized as an essential component of an effec­tive infection control program. Surveillancemay be defined as a system for collecting,tabulating, analyzing, and reporting data onthe occurrence of nosocomial infections.' Manysurvcillancc methods have been described byvarious experts, but all effective systems haveone common requirement, available time inwhich to collect the data.

A good surveillance program provides the fol­lowing information":

1. Identification of nosocomial pathogenscommonly encountered in the particularenvironment

2. Estimates of endemic levels of nosocomialinfection for a particular hospital and forthe individual services

Reprint requests: Sandra Blake. R.N.. B.S.N, Infection ControlNurse, Memorial Medical Center. 800 N. Rutledge. Springfield.IL 62702.

3. Prompt recognition of epidemics4. Identification of educational needs of

hospital personnel regarding good infec­tion control practices

A method for surveillance of nosocomial in­fections has been described by the Center forDisease Control and is also supported by theAmerican Hospital Association. This approachutilizes a surveillance person who makesrounds on the nursing units (preferably daily)to review charts of patients in isolation or rc­ceiving antibiotics and special treatments andwhoalso visits the X-Ray Department to reviewpositive chest findings.":" The Center for DiseaseControl advocates that a full-time surveillanceperson be employed in hospitals that havemore than 400 beds based on a ratio of 10 hoursper week per 100 beds.

A somewhat modified approach has been de­scribed by other authors. One method de­scribed utilizes a weekly review of the nursingcare plan to select high-risk patients for a chart

75

76 Blake, Cheatle, and Mack

review. However, in this study about 65% of thetotal population fell into the high-risk group;therefore large numbers of charts still requirereview by the surveillance person." In ourteaching hospital, obtaining the patient's chartfor review is often a problem as the chart isfrequently being used by the medical staff ormay be off the unit with the patient in anotherdepartment such as radiology or physical ther­apy. Nursing personnel are also very busy, andit is often difficult to discuss a patient's condi­tion with the nurse in charge of his care. Theseproblems all increase the amount of time re­quired for surveillance.

Our Infection Control Committee believedthat employee education should have at least asmuch emphasis as surveillance. Therefore totalhospital surveillance seemed impossible. Pos­sible solutions to this dilemma were to hiremore surveillance personnel or do smaller stud­ies concerning individual problems such aswound infections during a designated period oftime. Employing additional personnel was notpossible. It was decided to abandon total sur­veillance and concentrate on selected studiesand employee education.

However, in reviewing our problem it wasfound that medical records administrators werealready accumulating data on hospital infec­tions. These personnel were trained to use thedefinitions of infection approved by the In­fection Control Committee and medical staff inreviewing charts. Data were collected retro­spectively. However, the Infection ControlCommittee was unsure if data collected and re­ported by the Medical Records Departmentwas as accurate as data collected prospectivelyby the infection control nurse. In fact, some au­thors have stated that review of nosocomial in­fections by the medical records technicianswould be an inaccurate means of surveillance."Therefore a special surveillance study on twonursing units was conducted to compare sur­veillance data collected retrospectively by theMedical Records Department and prospectivelyby the infection control personnel. It washypothesized that the prospective data col­lected by the nurses would be more accurate.The study was done over a 4-month period.

Amencan Journal of

INFECTION CONTROL

METHODS

The same guidelines for identification andclassification of infections were used by bothmedical record technicians and infection con­trol personnel. These guidelines were adapta­tions of those recommended by the CDC.

All charts were reviewed by the Medical Rec­ords Department within several days of dis­charge. The same two individuals in this de­partment reviewed the charts, searching fordocumentation of nosocomial infections. In­formation recorded included the patient'sname, record number, service, nursing unit,site of infection, criteria present on the chart,cultures and other significant laboratory re­ports, treatment, admission dates, and dis­charge dates. These data were then reviewed bythe infection control nurse. Finally, the datawere assimilated into the report that comprisesthe monthly nosocomial infection report andwas always completed within 4 weeks after theend of a month. Once a month the infectioncontrol nurse spent about 6 hours reviewingdata collected by the Medical Records De­partment.

Prospective surveillance was done on the twonursing units (a medical unit and a surgicalunit) by two nurses. The two nursing units werevisited two to three times per week. Patientcharts were reviewed with module leaders usingthe Kardex care plan as a basis for discussion.Special attention was given to patients with ele­vated temperatures, those on antibiotic therapyor special treatments such as soaks and irriga­tions, patients with intravenous catheters orFoley catheters, and patients in isolation. Alsocharts of patients with positive microbiologycultures were reviewed. When an infection wasidentified, data were collected on a special sur­veillance sheet. Data collected included the pa­tient's name, physician's diagnosis, nursingunit, site of infection, organisms isolated andtheir sensitivities, surgical procedures, andpredisposing factors. Monthly reports were pre­pared for each of the two units. Prior to com­mencing this surveillance, in-service confer­ences were conducted to acquaint unit nurseswith the study objectives and the guidelinesused in determining the presence of an infection.

Volume 8 Number 3

August. 1980

RESULTS

At the en d of the study, cases of infectionsfound by the Med ical Records Departmen twere compare d to those found by the nurseteam in thes e two un its . Th e data were re­viewed by a sta tist ician to establis h whetherth ere was a difference in efficacy (in re porti ngrates) for the two approaches and to esta blis hth e extent of such a d ifference if one exi sted.The data collected are sho w n in Table 1.

To determine if there was a difference in re­porting for the tw o approache s, a McNemartest of correlated proportions with a signifi­ca nce level of 0.05 was used . The value ob­taine d fro m the McNemar test was 5.26 , orusing the Yates "correction for co n t inui ty," ava lue of 4.35. This statistic is co m pared to the0.05 critical va lue of th e chi-square di st ribu­t ion , wh ich is 3.84. S ince the va lue obtainedexceeds the cr itical va lue , a hyp othesis of nodi fference is rej ect ed. The Medical Records De­pa rtmen t, in fact , reported more infectionsthan the nurse team.

Statis tical methods to assess the exte nt of thedifference we re a lso used . It was determinedthat of the infec tions reported by the medicalrecord technici ans , 35% were mi ssed by thenurse team. Of those re ported by the nurses ,16% were missed by the medical record tech­n icians.

CONCLUSION

In sum mary, the rep ort ed infection rates ofthe two methods were found to be different.The Medical Records Departm ent mi ssed sub­stan tially fewer of the in fect ions reported bythe nurse team than the nurse team missed ofthose re por ted by the Medical Record s De­partment . Therefore it was co ncl uded th at theMed ical Records Dep a r tmen t was more sensi­t ive to ide n tifying infections than the nurseteam.

In evaluating th e results of this surv ey, thereare several po ints of di scussion. First , why we rethe medical records personnel more se ns it ive toidentifying in fection s than the nurse tea m ?Several obvious reasons exist that may ex p lainthis di fference. Firs t , a ll records are re viewedby the sa me personnel in the Medical Records

Surveillance: Retrospect ive vs . prospective 77

Table 1. Nosocomial infections found by theMedical Records Depa rtment and /o r the infect ioncontrol team

Ward A Ward B Total

Patients discharged 685 492 1177Noninfected 651 470 1121Detected by nurses only 4 2 6Detected by Med ical 7 10 17

Record s Dept. onlyDetected by both 21 10 31Disrepancy between report s 2 0 2

Dep artment. These people are consistent inth ei r use of the criteria for id entifying in­fections . On the ot her ha nd , the two nurseswere occasionally absent at the same ti me andth erefore did not review all patient charts dur­ing the course of the survey. It was no ted thatsome of the infections mi ssed by the nu rse tea mdid occur during the ir absence .

In ad dition, a t least one infection was missedby the nurse team becaus e the pat ient di ed be ­tween the nurse's vis it to the un it and the inci­dent was no t broug ht to the a ttention of thenurse tea m. Ho we ver , la borat ory data pl us thephysician 's comments were on the patient 'srecord, thus a llowing the Medical Records De­part ment to id entify this infection.

The nurse te a m di d review the infec tionsfound by the Medical Records Department andfound they counted two infections that thenurse team would no t ha ve coun te d . However,bo th of these infection s had been diagnosed bya physician.

In th is study the Medical Recor ds Dep a r tmentdi d prove to be efficient and accurate in iden­tifying nosocomial infections . In our 600- bedhospital this system can en hance the abi lit y ofinfection contro l personnel to expand survei l­lance activ it ies . Because the Med ical Recor dsDepartment can supply th e infection co ntrolteam wit h monthly da ta on th e occurrence ofnosocomia l infect ions , both for the entire hos­pital and for the individual units and services ,a nd sites of infect ion and organisms isol a ted ,the infect ion control team 's surveillance ac­t ivities can be d irected towa rd more specificstudies. The Medical Records Dep artment re­port can provide baseline data every m onth

78 Blake, Cheatle, and Mack

tha t shou ld indicate trends . When an increasein infections or a potential problem is iden­tified , a specia l study can be conducted . Forexa mp le , if an increase in the wound infectionrate of clean surgical cases is noted, an in-depthstudy can be done by the infection controlteam.

In conclusion, by having the Medical RecordsDepartment compile a monthly nosocomial re­port, the infection control team is provided theba sic data needed , leaving more time availa blefor special studies and employee ed ucation.

ADDENDUM

Since completion of th is study . efforts ha ve beenmad e to ex pand the useful ness of thi s retrospectivesu rveil la nce system . At th e present time the use of aca rbo ne d worksheet is being eva lua te d. As soon asthe medical record s technicians review the ch artsand com plete the work sh eet . a cop y of the sheet issen t to the infection con trol nurse . Also . rather thandoing a review of th e charts a t th e end of the month .th e infection control nurse is pl anning to review th einfec tions identified by th e Medical Records De­partment on a weekly ba sis .

In addition. " bug surveillance." as described byMaryanne McGuckin, infection con tro l practitionera t th e Hospital of the Uni versity of Pennsylvania. isbeing initiated . This " bug surve illa nce" has be en

American Journal of

INFECTION CON TROL

designed to detect potential ep ide m ics with the useof mi crobiology reports from th e laboratory. Thismethod provides dat a dail y .' Microbiology reportsa re being recorded dail y by a cleri cal as sis ta n t.

It is bel ieved that th ese syste ms together will pro­vide a thorough but timesav in g sys te m for no soco­mi al infection surveillance.

We wish to th ank Tom Men ten for his assi st an ce in th es ta tist ica l evaluation of th e dat a .

References

I . Krause S. Pappas S: The nurse epidem iologist : Role andresponsibili ties . Top Clin Nurs 1:2-3, July, 1979

2. Eickhoff T, Branchma n P. Bennett J , et al: Surveillanceof nosocomial infection in co m mun ity hospitals. 1. Sur­veillance methods, effectiven ess . and initial results . J In­fect Dis 120:305 -317, 1969

3. Amer ican Hospital Associat ion : Infection control in th ehospital. Chicago. 1979 . Th e Association , pp 24-25

4. Garner JS . Bennett JB. Sch eckler WE . et al : Surveil­lan ce of nosocomial in fecti ons . I n Proceedings of th e In­tern at ion al Conferen ce on Nosocomial Infections . At­lanta . Aug 1970, Center for Disease Control, pp 277-281

5. Wenzel R . Osterman D, Hunting K, et a l: Hospital ac ­quired infections. Surveillance in a university ho spital .Am J Epidemiol 103:251 . 1976

6. Macpherson CR. Practical problem s in the detection ofhospital-acquired infections . Am J Clin Pathol 50 :155.1967

7 . McGu ckin M: An innovative approac h to surv eilla nce ofnocomial outbreaks. Qu al Rev Bull, March . pp 12-17 .1979

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