T. Allan Pryor

Evaluation of size and dynamics of the inferior vena cava as an index of right-sided cardiac function.

To define normal criteria of size and dynamics of the inferior vena cava (IVC) and its clinical value in assessing right-sided cardiac function, 2-dimensional (2-D) and M-mode echocardiography (echo) were performed in 175 subjects, who were classified into 3 groups: group 1-80 normal subjects; group IIA--65 patients with documented right-sided cardiac disease, and group IIB--30 patients with cardiac disease but no right-sided abnormality. The IVC was adequately imaged in 175 of 185 subjects (95%). There was good correlation between M-mode and 2-D echo (r = 0.84) and long- and short-axis (r = 0.88) measurements. The IVC diameter during expiration was: group 1-9 to 28 mm (mean 18.2 +/- 4.6); group IIA--15 to 40 mm (mean 23.1 +/- 4.8) and group IIB-8-24 mm (mean 15.6 +/- 3.7). Collapsibility index (inspiratory decrease in diameter) was: group I-37 to 100% (mean 55.8 +/- 15.9); group IIA--0 to 39% (mean 13.5 +/- 10.5); and group IIB--44 to 100% (mean 60.4 +/- 13.1). A and V waves could be measured in 120 of 151 cases (79%). Both A and V waves were less than 125% of its diameter in group I. The A wave was absent in 34 patients; 30 (88%) were in atrial fibrillation. Among 8 patients with tricuspid regurgitation, 5 (63%) had V waves greater than 125%. There was no correlation between diameter or collapsibility index and age, sex, rhythm or body surface area.(ABSTRACT TRUNCATED AT 250 WORDS)

HELP: A Dynamic Hospital Information System

The HELP (Health Evaluation through Logical Processing) system is a computerized hospital information system developed by the authors at the LDS Hospital at the University of Utah, USA. It provides clinical, hospital administration and financial services through the use of a modular, integrated design. This book thoroughly documents the HELP system. Chapters discuss the use of the HELP system in intensive care units, the use of APACHE and APACHE II on the HELP system, various clinical applications and inactive or experimental HELP system modules.

The arden syntax for medical logic modules

The Arden Syntax for sharing medical knowledge bases is described. Its current focus is on knowledge that is represented as a set of independent modules that can provide therapeutic suggestions, alerts, diagnosis scores, etc. The syntax is based largely upon HELP and the Regenstrief Medical Record System. Each module, called a Medical Logic Module or MLM, is made of slots grouped into maintenance, library, and knowledge categories. The syntax has provisions for querying a clinical database and representing time. Several clinical information systems were analyzed and appear to be compatible with the syntax. The syntax has been tested for syntactic ambiguities using the tools lex and yacc. Seventeen institutions are currently in the process of adopting the Arden Syntax for their decision-support systems. A subcommittee of ASTM has been formed to develop standards for sharing medical knowledge bases. The Arden Syntax has been published by ASTM as a initial standard for sharing medical knowledge.

Development of a computerized laboratory alerting system

Using the capabilities of the HELP medical information system at LDS Hospital, a Computerized Laboratory Alerting System (CLAS) was developed. CLAS monitors and alerts for the presence of life-threatening conditions in hospitalized patients which are indicated by laboratory test results. Alerts are posted on computer terminals on the hospitals nursing divisions, where they are reviewed and acknowledged by hospital staff so that appropriate treatment can be rapidly instituted. CLAS was evaluated to determine its effectiveness in relaying alerts to the clinical staff, and improvements were made to develop an effective user interface. Initial average alert response times on nursing divisions ranged from 5.1 to 58.2 hr. The average alert response time dropped to 3.6 hr when alert review was integrated with laboratory result review, and to 0.1 hr after installation of a flashing light to notify hospital staff of the presence of new alerts.

Computerized Laboratory Alerting System

A computerized laboratory alerting system (CLAS) has been developed as part of an ongoing effort to improve the quality of care at LDS Hospital. The system identifies potentially life-threatening conditions on the basis of laboratory findings and then generates appropriate warnings and transmits them to clinicians. Use of the system has led to a significant increase in the proportion of patients in life-threatening situations who have received appropriate care (50.8% before implementation vs. 62.5% afterward, P less than 0.05). Among patients with hypokalemia, falling potassium levels, hyperkalemia, hypokalemia during treatment with digoxin, hyponatremia, falling sodium levels, hypernatremia, hypoglycemia, or hyperglycemia, the average length of time spent in the life-threatening situation has decreased from 30.4 to 15.7 hours (P less than 0.05) and the average length of stay has decreased from 14.6 to 8.8 days (P less than 0.05). There has been little change in the proportion of patients with findings indicating metabolic acidosis who have received appropriate care (32.3 vs. 34.6%). We conclude that CLAS has an important role in patient care at our hospital.

Older age and elevated blood pressure are risk factors for intracerebral hemorrhage after thrombolysis

Intracerebral hemorrhage is an important concern after thrombolytic therapy for acute myocardial infarction, but risk factors are controversial. Accordingly, we assessed risk factors in 107 treated patients of whom 4 had intracerebral hemorrhage. Intracerebral hemorrhage occurred at a mean of 25 hours (range 3.5 to 48) after therapy and was fatal in 2 patients. Significant differences were found between patients with and without intracerebral hemorrhage for age (77 +/- 7 vs 62 +/- 11 years, p less than or equal to 0.01), and initial (161 +/- 23 vs 135 +/- 23 mm Hg, p less than or equal to 0.03) and maximal (171 +/- 30 vs 146 +/- 20, p less than or equal to 0.02) systolic blood pressures. Initial and maximal diastolic blood pressures also tended to be higher (101 +/- 25 vs 86 +/- 16, p less than or equal to 0.07; 104 +/- 24 vs 90 +/- 13, p less than or equal to 0.06). Differences did not achieve significance for comparisons of gender, height, weight, site of infarction, time to therapy, specific thrombolytic agent used, concomitant therapy, interventions and partial thromboplastin time. It is concluded that age (greater than or equal to 70 years) and elevated blood pressure (greater than or equal to 150/95 mm Hg) are important risk factors for intracerebral hemorrhage. The overall balance of benefit and risk of thrombolysis should continue to be assessed by large mortality trials.

Electrocardiographic interpretation by computer.

Abstract A program for the automatic interpretation of electrocardiograms using a general purpose digital computer has been under development at the Latter-day Saints Hospital. The analysis is performed using the orthogonal XYZ Franck lead system. This system was chosen in order to reduce the amount of data transmitted and analyzed by the computer. Interpretive statements are made concerning only the QRS and ST-T waves of the electrocardiogram at this time. Development is under way for interpretation of the P wave as well as arrhythmia diagnosis.

Analysis of B-scan speckle reduction by resolution limited filtering

Much of the signal energy due to speckle in ultrasound images is shown to be of higher spatial frequency than the intrinsic pulse shape limited resolution in B-scan ultrasound images. A significant increase in signal to noise ratio can therefore be obtained by resolution limited spatial filtering which selectively removes energy of higher spatial frequency than the pulse envelope resolution limit. The concept is illustrated by resolution limited filtering ECG gated B-scan echocardiographic images. Signal to noise improvement is illustrated by comparing time-motion displays generated from both processed and unprocessed images.

Computerized nurse charting.

Computerized nurse charting programs have been used at LDS Hospital for over two years. These programs allow the nurse to create nurse care plans for the management of the patient, and chart on the computer actions and information which support the documentation of the management of the patient according to the care plan created for the patient. Computer terminals have been placed at the patients bedside to facilitate the use of these programs. This paper describes the programs available at LDS Hospital and several evaluation studies which have been performed to measure the efficacy of the programs. The evaluation studies indicated an increase in the level of documentation completeness and accuracy by the nurse but at some minor expense to time available to the nurse for patient care. Evaluation of the need for bedside terminals versus centrally located terminals showed an overwhelming desire by the nurse in favor of the bedside terminal. It was also found that data was entered more timely with less waiting when bedside terminals were available. Physician acceptance of the nurse charting system was found to be favorable.

Computer system for research and clinical application to medicine

Since June, 1964, a Control Data 3200 computer system has been installed in the Latter-day Saints Hospital in Salt Lake City, Utah, under support from NIH grant FR-00012. This system in its inception was used to develop research programs and time-sharing software for use by the medical community in the Salt Lake City area. As a result, a software and hardware system called MEDLAB has been developed. Using this system, research programs were developed for cardiovascular studies. It soon became apparent that the programs which were being developed could also be used in a clinical environment.