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The storage and analysis of cardiology casesheets by digital computer
THE STORAGE AND ANALYSIS OF CARDIOLOGY CASESHEETS BY DIGITAL COMPUTER BRYAND. YOUNG Department of Clinical Physics and Bio-engineering Western Regional Hospital Board, Glasgow (Great Britain) and JOHNA. KENNEDY University
Department of Medical Cardiology, Glasgow (Great Britain)
Royal Infirmary
(Received: 6 January, 1970) SUMMARY
The CARDIAC system (Casesheet Recording and Analysis by Computer) has been developed on a PDP8 computer to store and examine cardiology casesheet information. A document for use by medical staff has been designed to record all clinical data in either text or numerical form. Information on the document is reproduced on paper tape and in this form is transferred by the computer to digital magnetic tape for permanent storage. The CARDIAC system incorporates four programs, each written in machine assembly language. (1)
The system input program controls the transfer of casesheet information from paper tape to the storage magnetic tape.
(2)
The system output program prints a concise summary of each stored casesheet using a variety of formats which include grammatically correct sentences and simple tables.
(3)
The system analysis program searches the storage magnetic tape for patients satisfying a set of criteria chosen by the user.
(4)
The system editing program facilitates the alteration of stored casesheets.
SOMMAIRE
Le systtme CARDIAC (enregistrement et analyse par ordinateur du dossier du cas) a e’te developpe’sur un ordinateur PDPS pour emmagaziner et examiner les renseignements de dossiers de cas cardiologiques. Un document a I’emploi du personnel medical a ete e’tudie’ pour enregistrer toutes les donnees cliniques, soit en mots ou en chtflres. 115 Bio-Medico1Computing(1) (1970)-Q Elsevier Publishing Company Ltd, England-Printed
in Great Britain
116
BRYAN D. YOUNG,
JOHN A. KENNEDY
Les renseignements sur le document sont reproduits sur une bande en papier et sous cette forme sont transferes par l’ordinateur a une bande magne’tique et digitale pour emmagazinage permanent. Le systeme CARDIAC incorpore quatre programmes, chacun e’crit au langage de montage de machines. (1) Le systeme d’entree du programme regle le transfert de renseignements relatif au dossier du cas de la bande en papier a la bande magne’tique d’emmagazinage. (2) Le systeme de sortie du programme imprime une sommaire concise de chaque dossier de cas emmagazine, en utilisant un assortiment de formats, parmi lesquels des phrases qui sont exactes du point de vue de grammaire, et des tables simples. (3) Le programme d’analyse de systeme cherche dans la bande magnetique d’emmagazinage des malades qui satisfont h un groupe de criteriums choisis par &sager. (4) Le programme pour editer le systlme,facilite Ie remaniement de dossiers de cas emmagazines.
INTRODUCTION
The use of the digital computer for storage and analysis of medical records will bring benefits to both hospital administration and clinical research. Progress towards a fully automated system of hospital case-record storage has been made in several centres (Levy, et al., 1964; Ausman, et al., 1966; Cross, et al., 1968; Bennett, et al., 1968; Kennedy, et al., 1968). In the development of all such systems a problem which must be tackled is the choice and organisation of clinical data into a form suitable for computer storage. This requires a detailed evaluation of all the clinical information available for storage. The CARDIAC system (Casesheet Recording and Analysis by Computer) has been developed for storage and analysis by a digital computer of casesheet information about patients admitted to hospital for investigation of rheumatic or congenital heart disease. The main aim of this system is to provide the clinician with an easily accessible store of information about details of physical examination and diagnosis of such patients. The most notable feature of the CARDIAC system is that it has been developed using the relatively small PDP8 digital computer. Although, in practice, this has imposed certain restrictions in the design of the system, the resulting simplicity of documentation is appreciated by medical staff. This computer-based system provides facilities for the examination and analysis of cardiology patient casesheets with a speed and accuracy not possible by conventional methods of casesheet storage. However, it should be noted that an automated system of medical record storage which greatly increases the work load of clinicians
STORAGE
AND
ANALYSIS
OF CARDIOLOGY
CASESHEETS
BY DIGITAL
COMPUTER
117
would soon lose their favour and therefore minimise its data handling advantages. Hence it was felt that the introduction of such a system should interfere as little as possible with current methods of collecting clinical data.
METHODS
Casesheet document The first task necessary in the development of the CARDIAC system was the design of a document acceptable to medical staff for recording clinical information. It was decided that this document, while reducing as much information as possible to a numerical form, should be both compatible with existing methods of casesheet reporting and easy to use by the clinician. Close collaboration between scientific and medical staff was essential to achieve a suitable design. SECTION Cl. EXAMINATION DATE:
Day
Mth
Year
03
07
Cl7
PHYSICIAN Inches
:: 3.
HEIGHT WEIGHT BUILD
4.
TEETH
1
0 = Normal;
:. 7: ::
CENTRAL CYANOSIS PERIPHERAL CYANOSIS OEDEMA CLUBBING PALLOR
: E
0 = None; 0 = None; 0 = None: O=None;
Co
= Normal; ?H0?0Lbs 3 = Muscular
(14)
1 = Overweight: 1 = Dentures; 1 = Slight; 1 = Slight; 1 = Slight; l-Yes
J.V.P. A Wave V Wave RHYTHM PULSE RADIAL
15. 16.
VOLUME CHARACTER
17118. 19/20.
BLOOD PRESSURE : Physical examination
2 = Slim; 2 = Caries
2 = Prominent 2 = Prominent 2 = Prominent
CARDIOVASCULAR SYSTEM 0 = Normal; 1 = Elevated; R 0 = Normal; 1 = Absent; 0 = Normal; 1 = Absent; Irregular 0 = Sinus; Regular: 1 =1 =A.F. :
10. 11. 12. 1::
Fig. 1.
Ii
2 = H.J. Reflux 2 = Prominent 2 = Prominent
0 = Normal; 1 = Small; 2 = Large 2 = Bisferiens; 0 = Normal; 1 = Anacrotic; 3 = Collapsing RIGHT 000 / ?? OC LEFT 000 / Cl00 section of the casesheet document.
Information is recorded on the document in either of two forms, viz. the text form and the numerical form. The text form is used to record basic information about each patient, e.g. name, address, occupation and also written comments where applicable. However, most information is recorded in the numerical form according to simple codes which are listed in the document. This is illustrated in Fig. 1 which shows the first page of the physical examination section.
118
BRYAN D. YOUNG,
JOHN A. KENNEDY
The document which is 16 pages in length is divided into 11 sections under the following headings : Basic Information, History, Past History, Family History, SocialHistory,PreviousTreatment,PhysicalExamination, RheumaticHeart Disease: Provisional Diagnosis, Congenital Heart Disease: Provisional Diagnosis, Chest Radiology, Electrocardiogram. Each of these sections has a format which is suitable for the particular informais recorded tion being recorded; e.g. in the Family History section, hypertension as follows: SPECIFY HYPERTENSION
0
0 = NO;
1 = YES
/I
(16)
In this case the first box contains a 1 or a 0 according to whether or not there is a family history of hypertension and the second box allows the clinician to use up to 16 characters of text form to be more specific about the family relationship. There is provision for written comments at the end of most sections. Since all zero entries may in practice be omitted, the time required by the clinician to complete the document is not much greater than that to examine each patient. This is important since it is felt that, in the development of computer-based recording systems, consideration should be given to the problem of reducing the work load of clinicians. Storage On completion of the casesheet document, the data contained therein are converted into eight-hole paper tape on an off-line teletype. This coding procedure has been simplified to reduce the possibility of typing errors but any detected at this stage can be easily corrected on the teletype. The simplicity of this process has meant that, in practice, a secretarial typist can be quickly trained to perform this task. The system input program is used to transfer the paper tape version of the casesheet on to digital magnetic tape for storage. This program checks for typing errors in the paper tape which is rejected if any are detected. Part of each storage magnetic tape which has a capacity of 180 casesheets is reserved for book-keeping purposes so that a current record is kept of the total number of casesheets stored. Each completed document is given an identification number which effectively allocates to it a block of 1024 12 bit words on the storage magnetic tape. To allow for future expansion of the system only 768 words are used at present. Each block has a fixed format with numerical entries on the document stored as positive 12 bit numbers and text stored in trimmed 6 bit ASCII code, packed two characters to a 12 bit word. As a safeguard against damage or loss of the storage tape it is duplicated periodically. The system editing program is used for the alteration of information on the storage magnetic tape. A casesheet requiring to be changed is read from the storage tape, altered by the user and re-written on to tape. This program is useful for the occasional correction of casesheet errors.
STORAGE
AND ANALYSIS
OF CARDIOLOGY
CASESHEETS
BY DIGITAL
COMPUTER
119
Casesheet print out Although the main aim of this project is to accumulate a store of data in an accessible form, it was apparent that the text generating ability of the computer could be used to produce an automatically printed summary of each patient’s casesheet. The system output program has been written to produce such a document which presents almost all of the information in the original casesheet in an intelligible form. An example of the first page of this summary is shown in Fig. 2 where it can DEPARTMENT
OF
GLASGOW DATE OF ADMISSION: JOHN SMITH GLASGOW SEX: MALE
MEDICAL CARDIOLOGY ROYAL INFIRMARY
2-3-69 AGE: WARD
DR GRANT GLASGOW
37 YRS.
HOSPITAL
NO: 220933
NO: 7
PHYSICIAN
: PROF
LAWRIE
HISTORY. . . . HE HAS A HISTORY THERE WERE NO PRESENTING SYMPTOMS. OF MILD RECURRENT BRONCHITIS, MILD CHRONIC COUGH, SPIT AND WHEEZE. WEIGHT CHANGE IN PAST 2 YEARS -28 LBS. PAST HISTORY. . . . HE HAS A PAST HISTORY
AS FOLLOWS:~
DATE
JOINT PAINS; GROWING PAINS 1953 KNOWN HEART LESION SINCE 16 YEARS OF AGE PREVIOUS HOSPITALISATIONS :-DIPHTHERIA AGE 7 -HAWKHEAD Fig. 2.
An example of the first page of computer print-out.
be seen that a variety of output formats has been adopted. In the History section the information is assembled into grammatically correct sentences, whereas in the Past History section information is presented in the form of a simple table. Each summary is automatically subdivided into six pages compatible in length with other clinical documents although in practice it is produced on a high-speed paper tape punch for subsequent off-line printing. Since this is a concise summary of the original casesheet it is kept as a permanent record in the patient’s file. An advantage of this type of system over conventional methods of record storage is that as all information is stored permanently on magnetic tape a summary of any casesheet can be produced rapidly when required. Analysis of stored data No system of medical record storage would be complete without comprehensive facilities for analysis. The system analysis program has been written to perform this
120
BRYAN D. YOUNG,
JOHN A. KENNEDY
task by searching all the stored casesheets for patients who satisfy particular criteria defined by the user. At the end of the search, the total number of these patients and the numbers of male and female patients are given. More detailed information about these patients can be printed if required; this includes name, hospital number, date of admission and age. It is possible to restrict the search to any particular age group and in this way the analysis program can be used to produce age histograms. Since all the criteria used for the searching procedure are defined by the user, a large number of combinations can be chosen. Criteria can be selected from any information which is entered on the casesheet document in the numerical form, but information stored in the text form cannot be examined in this way. The type of request which can be answered by the system analysis program is illustrated in the following examples: (1) How many male patients over the age of 45 with rheumatic heart disease have a positive X-ray and electrocardiogram? (2) How many patients with rheumatic heart disease have a past history of rheumatic fever? Print the names and ages of all patients with cyanotic congenital heart (31 disease. These examples indicate the broad range of criteria which can be selected. The system analysis program requires only one minute to search a complete storage tape, thereby providing facilities for the rapid statistical evaluation of these medical records. This program has been used to examine all the casesheets storedduringthe TABLE A
SUMMARY
OF
THE
STORED
I
CASESHEETS
ANALYSIS
PRODUCED
BY
THE
SYSTEM
PROGRAM
Male
Female
Total
Number of patients Rheumatic heart disease Congenital heart disease Abnormal X-ray Abnormal electrocardiogram
first eight months tions.
of operation,
and Table I shows the results of five basic applica: DISCUSSION
The CARDIAC system demonstrates how a small digital computer can be programmed to perform storage and analysis of patient casesheet information. Such a computer, sited within a hospital department, offers advantages in terms of cost and accessibility over a more powerful but remote computer. It has, however, the
STORAGE
AND ANALYSIS
OF CARDIOLOGY
CASESHEETS
BY DIGITAL
COMPUTER
121
disadvantage of small core store and word length which in this application necessitated a degree of simplicity in the system software. It is felt that the viability of computer-based systems for medical record storage depends not on the complexity and sophistication of the programming techniques employed but on administrative factors such as ease of data collection, simplicity of documentation and speed of transfer of information from the coded casesheet document on to the storage medium of the computer. The CARDIAC system requires approximately 20 minutes for the transfer of information from each original casesheet document to the storage magnetic tape. This time includes preparation of the paper tape and its subsequent transfer to the storage magnetic tape with the appropriate checking procedures. The time required to produce the printed casesheet summary is approximately 15 minutes, although this can be completed off-line. Although the system software has been developed specifically to handle relatively small numbers of cardiology casesheets (approximately 14 per month), there is no technical reason why the same programming methods could not be extended to handle larger numbers of casesheets of a more general nature. An intrinsic problem in the development of any system of medical record storage whether by conventional methods or by sophisticated electronic techniques is the proper selection of clinical information for storage. The importance of this cannot be overlooked since the ultimate success or failure of a system of record storage will depend on the reliability and relevance of the clinical data chosen. Distinction should be drawn between information of immediate significance and that of longterm statistical value. With automated systems of storage there is a temptation to record information regardless of its relevance. Besides increasing the work load of doctors in recording the clinical information this would tend to reduce the overall effectiveness of such a system. Computer facilities for systems of medical record storage are being continually developed. The problems which remain, apart from the expense and availability of computers, include familiarising medical staff with new systems of recording clinical data and training clerical staff to handle computer orientated medical records. Although such systems are not common in hospitals, it is felt that consideration should be given to the redesign of casesheet documents in use at present with a view to future computer storage. By familiarising medical staff at the present time with a new style of casesheet document, the inevitable introduction of computers into hospitals will be considerably eased.
ACKNOWLEDGEMENTS
The authors wish to thank Professor T. D. V. Lawrie who motivated facilities for this project and all members of staff who co-operated
and provided in this study.
122
BRYAN D. YOUNG, JOHN A. KENNEDY REFERENCES
AUSMAN,R. K., et al., Ann. New York Acad. Sci., 128(1966) p. 1100. BENNETT,A. E., and HOLLAND,W. W., Computers in the Service of Medicine (eds) G. MCLAUGHLIN and R. A. SHECOG,Vol. II, p. 119, London, 1968. CROSS, K. W., DROAR, J., and ROBERTS, J. L., Computers in the Service of Medicine (eds) G. MCLAUGHLIN and R. A. SHEGOG,Vol. I, p. 23, London, 1968. KENNEDY,F., CLEARY, J. J., ROY, A. D., and KAY, A. W., Lance& ii (1968) p. 1230. LEVY, R. D., CAMMARN, M. D., and SMITH, N., J. Amer. Med. Assoc. 190 (1964) p. 1033.
Department of Medical Cardiology, Glasgow (Great Britain)
Royal Infirmary
(Received: 6 January, 1970) SUMMARY
The CARDIAC system (Casesheet Recording and Analysis by Computer) has been developed on a PDP8 computer to store and examine cardiology casesheet information. A document for use by medical staff has been designed to record all clinical data in either text or numerical form. Information on the document is reproduced on paper tape and in this form is transferred by the computer to digital magnetic tape for permanent storage. The CARDIAC system incorporates four programs, each written in machine assembly language. (1)
The system input program controls the transfer of casesheet information from paper tape to the storage magnetic tape.
(2)
The system output program prints a concise summary of each stored casesheet using a variety of formats which include grammatically correct sentences and simple tables.
(3)
The system analysis program searches the storage magnetic tape for patients satisfying a set of criteria chosen by the user.
(4)
The system editing program facilitates the alteration of stored casesheets.
SOMMAIRE
Le systtme CARDIAC (enregistrement et analyse par ordinateur du dossier du cas) a e’te developpe’sur un ordinateur PDPS pour emmagaziner et examiner les renseignements de dossiers de cas cardiologiques. Un document a I’emploi du personnel medical a ete e’tudie’ pour enregistrer toutes les donnees cliniques, soit en mots ou en chtflres. 115 Bio-Medico1Computing(1) (1970)-Q Elsevier Publishing Company Ltd, England-Printed
in Great Britain
116
BRYAN D. YOUNG,
JOHN A. KENNEDY
Les renseignements sur le document sont reproduits sur une bande en papier et sous cette forme sont transferes par l’ordinateur a une bande magne’tique et digitale pour emmagazinage permanent. Le systeme CARDIAC incorpore quatre programmes, chacun e’crit au langage de montage de machines. (1) Le systeme d’entree du programme regle le transfert de renseignements relatif au dossier du cas de la bande en papier a la bande magne’tique d’emmagazinage. (2) Le systeme de sortie du programme imprime une sommaire concise de chaque dossier de cas emmagazine, en utilisant un assortiment de formats, parmi lesquels des phrases qui sont exactes du point de vue de grammaire, et des tables simples. (3) Le programme d’analyse de systeme cherche dans la bande magnetique d’emmagazinage des malades qui satisfont h un groupe de criteriums choisis par &sager. (4) Le programme pour editer le systlme,facilite Ie remaniement de dossiers de cas emmagazines.
INTRODUCTION
The use of the digital computer for storage and analysis of medical records will bring benefits to both hospital administration and clinical research. Progress towards a fully automated system of hospital case-record storage has been made in several centres (Levy, et al., 1964; Ausman, et al., 1966; Cross, et al., 1968; Bennett, et al., 1968; Kennedy, et al., 1968). In the development of all such systems a problem which must be tackled is the choice and organisation of clinical data into a form suitable for computer storage. This requires a detailed evaluation of all the clinical information available for storage. The CARDIAC system (Casesheet Recording and Analysis by Computer) has been developed for storage and analysis by a digital computer of casesheet information about patients admitted to hospital for investigation of rheumatic or congenital heart disease. The main aim of this system is to provide the clinician with an easily accessible store of information about details of physical examination and diagnosis of such patients. The most notable feature of the CARDIAC system is that it has been developed using the relatively small PDP8 digital computer. Although, in practice, this has imposed certain restrictions in the design of the system, the resulting simplicity of documentation is appreciated by medical staff. This computer-based system provides facilities for the examination and analysis of cardiology patient casesheets with a speed and accuracy not possible by conventional methods of casesheet storage. However, it should be noted that an automated system of medical record storage which greatly increases the work load of clinicians
STORAGE
AND
ANALYSIS
OF CARDIOLOGY
CASESHEETS
BY DIGITAL
COMPUTER
117
would soon lose their favour and therefore minimise its data handling advantages. Hence it was felt that the introduction of such a system should interfere as little as possible with current methods of collecting clinical data.
METHODS
Casesheet document The first task necessary in the development of the CARDIAC system was the design of a document acceptable to medical staff for recording clinical information. It was decided that this document, while reducing as much information as possible to a numerical form, should be both compatible with existing methods of casesheet reporting and easy to use by the clinician. Close collaboration between scientific and medical staff was essential to achieve a suitable design. SECTION Cl. EXAMINATION DATE:
Day
Mth
Year
03
07
Cl7
PHYSICIAN Inches
:: 3.
HEIGHT WEIGHT BUILD
4.
TEETH
1
0 = Normal;
:. 7: ::
CENTRAL CYANOSIS PERIPHERAL CYANOSIS OEDEMA CLUBBING PALLOR
: E
0 = None; 0 = None; 0 = None: O=None;
Co
= Normal; ?H0?0Lbs 3 = Muscular
(14)
1 = Overweight: 1 = Dentures; 1 = Slight; 1 = Slight; 1 = Slight; l-Yes
J.V.P. A Wave V Wave RHYTHM PULSE RADIAL
15. 16.
VOLUME CHARACTER
17118. 19/20.
BLOOD PRESSURE : Physical examination
2 = Slim; 2 = Caries
2 = Prominent 2 = Prominent 2 = Prominent
CARDIOVASCULAR SYSTEM 0 = Normal; 1 = Elevated; R 0 = Normal; 1 = Absent; 0 = Normal; 1 = Absent; Irregular 0 = Sinus; Regular: 1 =1 =A.F. :
10. 11. 12. 1::
Fig. 1.
Ii
2 = H.J. Reflux 2 = Prominent 2 = Prominent
0 = Normal; 1 = Small; 2 = Large 2 = Bisferiens; 0 = Normal; 1 = Anacrotic; 3 = Collapsing RIGHT 000 / ?? OC LEFT 000 / Cl00 section of the casesheet document.
Information is recorded on the document in either of two forms, viz. the text form and the numerical form. The text form is used to record basic information about each patient, e.g. name, address, occupation and also written comments where applicable. However, most information is recorded in the numerical form according to simple codes which are listed in the document. This is illustrated in Fig. 1 which shows the first page of the physical examination section.
118
BRYAN D. YOUNG,
JOHN A. KENNEDY
The document which is 16 pages in length is divided into 11 sections under the following headings : Basic Information, History, Past History, Family History, SocialHistory,PreviousTreatment,PhysicalExamination, RheumaticHeart Disease: Provisional Diagnosis, Congenital Heart Disease: Provisional Diagnosis, Chest Radiology, Electrocardiogram. Each of these sections has a format which is suitable for the particular informais recorded tion being recorded; e.g. in the Family History section, hypertension as follows: SPECIFY HYPERTENSION
0
0 = NO;
1 = YES
/I
(16)
In this case the first box contains a 1 or a 0 according to whether or not there is a family history of hypertension and the second box allows the clinician to use up to 16 characters of text form to be more specific about the family relationship. There is provision for written comments at the end of most sections. Since all zero entries may in practice be omitted, the time required by the clinician to complete the document is not much greater than that to examine each patient. This is important since it is felt that, in the development of computer-based recording systems, consideration should be given to the problem of reducing the work load of clinicians. Storage On completion of the casesheet document, the data contained therein are converted into eight-hole paper tape on an off-line teletype. This coding procedure has been simplified to reduce the possibility of typing errors but any detected at this stage can be easily corrected on the teletype. The simplicity of this process has meant that, in practice, a secretarial typist can be quickly trained to perform this task. The system input program is used to transfer the paper tape version of the casesheet on to digital magnetic tape for storage. This program checks for typing errors in the paper tape which is rejected if any are detected. Part of each storage magnetic tape which has a capacity of 180 casesheets is reserved for book-keeping purposes so that a current record is kept of the total number of casesheets stored. Each completed document is given an identification number which effectively allocates to it a block of 1024 12 bit words on the storage magnetic tape. To allow for future expansion of the system only 768 words are used at present. Each block has a fixed format with numerical entries on the document stored as positive 12 bit numbers and text stored in trimmed 6 bit ASCII code, packed two characters to a 12 bit word. As a safeguard against damage or loss of the storage tape it is duplicated periodically. The system editing program is used for the alteration of information on the storage magnetic tape. A casesheet requiring to be changed is read from the storage tape, altered by the user and re-written on to tape. This program is useful for the occasional correction of casesheet errors.
STORAGE
AND ANALYSIS
OF CARDIOLOGY
CASESHEETS
BY DIGITAL
COMPUTER
119
Casesheet print out Although the main aim of this project is to accumulate a store of data in an accessible form, it was apparent that the text generating ability of the computer could be used to produce an automatically printed summary of each patient’s casesheet. The system output program has been written to produce such a document which presents almost all of the information in the original casesheet in an intelligible form. An example of the first page of this summary is shown in Fig. 2 where it can DEPARTMENT
OF
GLASGOW DATE OF ADMISSION: JOHN SMITH GLASGOW SEX: MALE
MEDICAL CARDIOLOGY ROYAL INFIRMARY
2-3-69 AGE: WARD
DR GRANT GLASGOW
37 YRS.
HOSPITAL
NO: 220933
NO: 7
PHYSICIAN
: PROF
LAWRIE
HISTORY. . . . HE HAS A HISTORY THERE WERE NO PRESENTING SYMPTOMS. OF MILD RECURRENT BRONCHITIS, MILD CHRONIC COUGH, SPIT AND WHEEZE. WEIGHT CHANGE IN PAST 2 YEARS -28 LBS. PAST HISTORY. . . . HE HAS A PAST HISTORY
AS FOLLOWS:~
DATE
JOINT PAINS; GROWING PAINS 1953 KNOWN HEART LESION SINCE 16 YEARS OF AGE PREVIOUS HOSPITALISATIONS :-DIPHTHERIA AGE 7 -HAWKHEAD Fig. 2.
An example of the first page of computer print-out.
be seen that a variety of output formats has been adopted. In the History section the information is assembled into grammatically correct sentences, whereas in the Past History section information is presented in the form of a simple table. Each summary is automatically subdivided into six pages compatible in length with other clinical documents although in practice it is produced on a high-speed paper tape punch for subsequent off-line printing. Since this is a concise summary of the original casesheet it is kept as a permanent record in the patient’s file. An advantage of this type of system over conventional methods of record storage is that as all information is stored permanently on magnetic tape a summary of any casesheet can be produced rapidly when required. Analysis of stored data No system of medical record storage would be complete without comprehensive facilities for analysis. The system analysis program has been written to perform this
120
BRYAN D. YOUNG,
JOHN A. KENNEDY
task by searching all the stored casesheets for patients who satisfy particular criteria defined by the user. At the end of the search, the total number of these patients and the numbers of male and female patients are given. More detailed information about these patients can be printed if required; this includes name, hospital number, date of admission and age. It is possible to restrict the search to any particular age group and in this way the analysis program can be used to produce age histograms. Since all the criteria used for the searching procedure are defined by the user, a large number of combinations can be chosen. Criteria can be selected from any information which is entered on the casesheet document in the numerical form, but information stored in the text form cannot be examined in this way. The type of request which can be answered by the system analysis program is illustrated in the following examples: (1) How many male patients over the age of 45 with rheumatic heart disease have a positive X-ray and electrocardiogram? (2) How many patients with rheumatic heart disease have a past history of rheumatic fever? Print the names and ages of all patients with cyanotic congenital heart (31 disease. These examples indicate the broad range of criteria which can be selected. The system analysis program requires only one minute to search a complete storage tape, thereby providing facilities for the rapid statistical evaluation of these medical records. This program has been used to examine all the casesheets storedduringthe TABLE A
SUMMARY
OF
THE
STORED
I
CASESHEETS
ANALYSIS
PRODUCED
BY
THE
SYSTEM
PROGRAM
Male
Female
Total
Number of patients Rheumatic heart disease Congenital heart disease Abnormal X-ray Abnormal electrocardiogram
first eight months tions.
of operation,
and Table I shows the results of five basic applica: DISCUSSION
The CARDIAC system demonstrates how a small digital computer can be programmed to perform storage and analysis of patient casesheet information. Such a computer, sited within a hospital department, offers advantages in terms of cost and accessibility over a more powerful but remote computer. It has, however, the
STORAGE
AND ANALYSIS
OF CARDIOLOGY
CASESHEETS
BY DIGITAL
COMPUTER
121
disadvantage of small core store and word length which in this application necessitated a degree of simplicity in the system software. It is felt that the viability of computer-based systems for medical record storage depends not on the complexity and sophistication of the programming techniques employed but on administrative factors such as ease of data collection, simplicity of documentation and speed of transfer of information from the coded casesheet document on to the storage medium of the computer. The CARDIAC system requires approximately 20 minutes for the transfer of information from each original casesheet document to the storage magnetic tape. This time includes preparation of the paper tape and its subsequent transfer to the storage magnetic tape with the appropriate checking procedures. The time required to produce the printed casesheet summary is approximately 15 minutes, although this can be completed off-line. Although the system software has been developed specifically to handle relatively small numbers of cardiology casesheets (approximately 14 per month), there is no technical reason why the same programming methods could not be extended to handle larger numbers of casesheets of a more general nature. An intrinsic problem in the development of any system of medical record storage whether by conventional methods or by sophisticated electronic techniques is the proper selection of clinical information for storage. The importance of this cannot be overlooked since the ultimate success or failure of a system of record storage will depend on the reliability and relevance of the clinical data chosen. Distinction should be drawn between information of immediate significance and that of longterm statistical value. With automated systems of storage there is a temptation to record information regardless of its relevance. Besides increasing the work load of doctors in recording the clinical information this would tend to reduce the overall effectiveness of such a system. Computer facilities for systems of medical record storage are being continually developed. The problems which remain, apart from the expense and availability of computers, include familiarising medical staff with new systems of recording clinical data and training clerical staff to handle computer orientated medical records. Although such systems are not common in hospitals, it is felt that consideration should be given to the redesign of casesheet documents in use at present with a view to future computer storage. By familiarising medical staff at the present time with a new style of casesheet document, the inevitable introduction of computers into hospitals will be considerably eased.
ACKNOWLEDGEMENTS
The authors wish to thank Professor T. D. V. Lawrie who motivated facilities for this project and all members of staff who co-operated
and provided in this study.
122
BRYAN D. YOUNG, JOHN A. KENNEDY REFERENCES
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