Lightweight fuzzy processes in clinical computing

In spite of advances in computing hardware, many hospitals still have a hard time finding extra capacity in their production clinical information system to run artificial intelligence (AI) modules, for example: to support real-time drug-drug or drug-lab interactions; to track infection trends; to monitor compliance with case specific clinical guidelines; or to monitor/ control biomedical devices like an intelligent ventilator. Historically, adding AI functionality was not a major design concern when a typical clinical system is originally specified. AI technology is usually retrofitted 'on top of the old system' or 'run off line' in tandem with the old system to ensure that the routine work load would still get done (with as little impact from the AI side as possible). To compound the burden on system performance, most institutions have witnessed a long and increasing trend for intramural and extramural reporting, (e.g. the collection of data for a quality-control report in microbiology, or a meta-analysis of a suite of coronary artery bypass grafts techniques, etc.) and these place an ever-growing burden on typical the computer system's performance. We discuss a promising approach to adding extra AI processing power to a heavily-used system based on the notion 'lightweight fuzzy processing (LFP)', that is, fuzzy modules designed from the outset to impose a small computational load. A formal model for a useful subclass of fuzzy systems is defined below and is used as a framework for the automated generation of LFPs. By seeking to reduce the arithmetic complexity of the model (a hand-crafted process) and the data complexity of the model (an automated process), we show how LFPs can be generated for three sample datasets of clinical relevance.

Serum lactate and base deficit suggest inadequate resuscitation of patients with burn injuries: application of a point-of-care laboratory instrument

Urinary output of 30 to 50 ml/hr and mean arterial pressure of more than 70 mm Hg continue to be the yardsticks by which patients with burn injuries are resuscitated. We designed this prospective, descriptive study to compare these parameters with serial base deficit and serum lactate values, which have been found to be sensitive indicators of adequate fluid resuscitation in trauma patients. The sample group consisted of 53 patients, consecutively admitted to the burn intensive care unit, who had 15% or more total body surface area burns. No changes in resuscitation protocol were implemented. Within the 48-hour period after admission, 2 ml heparinized venous blood samples were collected and analyzed every 2 to 4 hours, and vital signs, urinary output, fluid type, and volume administered were documented each hour. Urinary output and mean arterial pressure were maintained at more than 30 ml/hr and more than 70 mm Hg, respectively. Partial correlations between the traditional resuscitation variables and serum lactate and base deficit were low. On average, serum lactate and base deficit remained abnormally high during the study period. These new parameters may be used to improve the fidelity with which burn shock resuscitation is undertaken. Further studies of these parameters and how they may be used as endpoints in fluid resuscitation are needed.

Point-of-care technology: a new perspective

Technology advances transform the staff nurses' work processes. Most importantly, however, they provide the potential to help nurses do what they've always wanted to do--spend more time with the patient, delivering nursing care. The nurse who has the tablet personal computer or "cart" computer right at hand can capture all the information that needs to be captured. Thus, the nurse executive has a greater body of automated information and data upon which to make managerial decisions.

Pocket-sized medicine. New POC technologies

Newer miniature testing and monitoring machines are profoundly changing the delivery of health care. Blood gases, X-rays, electrocardiograms, all can be done within the privacy of the patient's home. Yet, government regulations are just beginning to catch up with this technologic revolution. These technologies and their effect on patients and the health care environment are discussed.

Bedside autonomic function testing in patients with vasovagal syncope

The factors that determine the individual susceptibility to vasovagal syncope (VVS) are largely unknown, including the role of the autonomic nervous system. We therefore studied common vagal and sympathetic reflexes in 12 patients with VVS (mean age 37 (18-75) years, 6 men). The Valsalva maneuver and deep breathing were performed to assess vagal responsiveness and mental arithmetic stress; the cold-pressor test and isometric handgrip were performed to assess sympathetic responsiveness. Standing up was performed to assess the combined responsiveness. With the exception of a subnormal response to deep breathing in one patient, all vagal tests were normal. In contrast, the response to mental stress, the cold-pressor test, and isometric handgrip was subnormal in 4 patients, 6 patients, and 4 patients, respectively. The response to standing up was normal in all patients. It is concluded that many patients with VVS are characterized by normal vagal responsiveness, but sympathetic hyporesponsiveness. Sympathetic hyporesponsiveness might explain the inadequate vasoconstruction, which plays an important, early role in VVS.

The clinic-specific thesaurus: a means of "lean documentation" in pediatric surgery

A one-hundred percent documentation rate of diagnoses and patient data is unfeasible and should not be pursued. Therefore, a "lean documentation" of diagnoses and basic patient data was introduced. Coding is done by a clinic-specific list of diagnoses (thesaurus) with a minimum of diagnostic codes, combined with optional free text. By recording the frequency of diagnoses for two years, a thesaurus of 188 diagnostic codes was developed. Bedside coding by treating physicians reduced medical and semantic mistakes of documentation. Cooperation of the clinicians was obtained by shortening the time required for coding to less than two minutes per patient. A documentation assistant supplemented incomplete data in collaboration with the treating surgeons. During a ten-year testing period 93.7% of the hospital-specific codes of our thesaurus were required for documentation, as compared to 13.1% if the same patients were coded by ICD-9. Consequently, coding by a clinic-specific code thesaurus is quick flexible and accurate.

Long-term care facilities tackle clinical automation

Long-term care facilities building automation strategies face many challenges. In a market dominated by software for hospitals and clinics, they must make sure that the software they acquire meets the specific needs of the long-term care niche. For example, they need software that can collect data required by the federal government and that can be used to keep good nutritional records.

[The i-STAT analyzer. A new, hand-held device for the bedside determination of hematocrit, blood gases, and electrolytes]

Exact and quick measurements of basic laboratory parameters are important in selected patients in the perioperative period. Depending on the capabilities of a hospital's central laboratory, the anaesthesiologist may only obtain such laboratory tests after unacceptable delays. This problem may be overcome by a new bedside measurement device that has become available from i-STAT Corporation, Princeton, USA. The hand-held, battery-driven analyser accepts blood specimens that are injected into a disposable cartridge (EG7+) and measures acidity, blood gas tensions, haematocrit, and electrolytes. The aim of this study was to determine the accuracy of such measurements by comparing them with measurements obtained by conventional laboratory test methods.

METHODS

Heparinised arterial blood specimens were collected in duplicate from 49 surgical patients. Measurements of ionised calcium (Ca), sodium (Na), potassium (K), pH, pCO2, pO2, base excess (BE), haematocrit (Hct), and haemoglobin (Hb) obtained by the i-STAT analyser were compared with measurements from the calibrated analysers ABL 615 and EML 100 (Radiometer, Copenhagen). Because the i-STAT analyser calculates the Hb concentration from a conductometrically measured Hct, 19 blood specimens were centrifuged in order to compare test results with conventionally obtained Hct and Hb values. As the Hct test sensitivity with the i-STAT changes with diluted blood due to its low albumin concentration, Hct and Hb measurements during cardio-pulmonary bypass (CPB) must be corrected by activating an analyser-implemented correction algorithm (Hct/CPB and Hb/CPB). Correlation analysis was performed between conventional measurements and i-STAT values (Ca, Na, K, Hct, pCO2, pO2), between values that the i-STAT analyser derives (Hb, HCO3, BE) and conventionally obtained results, and between normal and CPB-corrected Hct and Hb values. Accuracy was judged according to the national quality standard, which requires test results to lie within the 95% confidence interval of conventional tests.

RESULTS

Each blood specimen was analysed: erroneous results or technical failures did not occur. Measurement of one set of i-STAT values required 2.5 min. Correlation coefficients (r) between conventional and i-STAT results were: 0.85 for CA, 1.0 for K; 0.86 for Na; 0.99 for pH; 0.98 for pCO2; 0.99 for pO2; 0.93 for HCO3; 0.93 for BE; 0.46 for Hb values not corrected for CPB and 0.95 for CPB-corrected Hb; and 0.74 for Hct values not corrected for CPB and 0.98 for CPB-corrected Hct. The correlation coefficient for Hct between centrifuged and CPB-uncorrected i-STAT values was 0.81 and that for CPB-corrected values was 0.98. National accuracy requirements were not met for tests of: Ca (by 0.02 mmol/l); pH (by 0.01); pO2 including hyperoxic values (by 26.7 mmHg, but were met for pO2 values < 200 mmHg); Hb (by 1.6 g/dl); Hb/CPB (by 0.8 g/dl); and Hct (by 6.5%, but were met for Hct/CPB values). All other tests fulfilled the required standards.

CONCLUSION

This analyser is easy to use, reliable, and portable, and therefore suitable for the operating room, for analyses during emergencies, on peripheral wards, for preclinical screening, or at times when availability of lab tests is time-consuming or limited. The test accuracy for electrolytes, blood gases, and Hb is high enough to justify routine use of the i-STAT analyser in clinical practice. That the nationally required quality standards for Ca, pH, and Hb were not met is not of importance because the measured deviation was too small to have clinical relevance. When analysing diluted blood with a low Hct and low oncotic pressure, it is important to activate the analyser's correction algorithm "CPB", because the obtained results will then comply with the required accuracy.

Computerized ventilator data selection: artifact rejection and data reduction

OBJECTIVE

To determine acceptable strategies for automated data acquisition and artifact rejection from computerized ventilators using the Medical Information Bus.

DESIGN

Medical practitioners were surveyed to establish 'clinically important' ventilator events. A prospective study involving frequent data collection from ventilators was also conducted.

SUBJECTS

Data from 10 adult patients were collected every 10 seconds from a Puritan Bennett 7200A ventilator for a total of 617.1 hours.

INTERVENTIONS

Twelve different computerized data selection and artifact algorithms were tested and evaluated.

MEASUREMENTS AND MAIN RESULTS

Data derived from 12 data selection algorithms were compared with each other and with data manually charted by respiratory therapists into a computerized charting system. Ventilator setting data collected by the algorithms, such as FIO2, reduced the amount of data collected to about 25% compared to manually charted data. The amount of data collected for measured parameters, such as tidal volume, from the ventilator had large variability and many artifacts. Automated data capture and selection generally increased the amount of data collected compared to manual charting, for example for the 3 minute median the increase was a modest 1.2 times.

CONCLUSION

Computerized methods for collecting ventilator setting data were relatively straightforward and more-efficient than manual methods. However, the method for automated selection and presentation of observed measured parameters is much more difficult. Based on the findings and analysis presented here, the authors recommend recording ventilator setting data after they have existed for three minutes and measured parameters using a three minute median data selection strategy. Such an algorithm rejected most artifacts, required minimal computational time, had minimal time-delay, and provided clinically acceptable data acquisition. The results presented here are but a starting point in developing automated ventilator data selection strategies.

A computing system for the clinical and experimental investigation of cerebrovascular reactivity

We present a computing system for the recording and on-line analysis of analogue signals derived from bedside cerebrovascular monitors in different pathophysiological conditions. These include arterial blood pressure and oxygen saturation, end-tidal carbon dioxide concentration, cerebral blood flow velocities using transcranial Doppler ultrasonography, and concentration changes in cerebral oxy- and deoxyhaemoglobin from near infrared spectroscopy. Configuration and analysis adopts arithmetic expressions of different signal processing functions, various statistical properties for each signal, frequency spectrum analysis using fast Fourier transformation, and correlation/cross-correlation. The software offers off-line analysis of non-invasive tests of cerebrovascular reactivity. Several examples of clinical assessment of cerebrovascular reactivity are presented, including cerebral haemodynamic stress tests which employ carbon dioxide, acetazolamide, the breath holding test, leg cuff inflation and deflation, and transient carotid artery compression. Application within the experimental setting with induced haemorrhagic hypotension can also be used.

The HP CareVue clinical information system

The HP CareVue system is an object-oriented, client-server system optimized for critical care, inpatient and special care environments. It is a fully graphical system, highly visual in its mode of operation, which requires no commands to operate. Data review may be performed by clinical users without specific instructions. Several different kinds of interfaces are provided for the system. These allow it to be connected to most hospital data-producing systems, physiologic monitors and bedside devices, such as ventilators, urimeters and oximeters. Flowsheet charting, free text, structured notes, clinical pathways, configurable forms, medication administration records and many other types of displays and reports allow the system to function as a nearly complete Electronic Medical Record (EMR). The system is highly configurable by lead nurses, physicians or technicians without programming knowledge or experience. Configuration and linking of multiple CareVue systems is possible, including a complete testing environment for verification of charting changes before clinical activation. All CareVue data is exportable for purposes of electronic archiving, warehousing and real-time decision support.

Chairside-fabricated indirect resin restorations: a new articulated technique

A case report of a chairside-fabricated indirect resin composite restoration is used to introduce a modification to a newly released one-appointment resin inlay-onlay technique. Fast-setting poly(vinyl siloxane) die material accommodates an articulated working cast within 10 minutes. The technique allows the economical construction of large, occlusal, load-bearing, extracoronal resin composite restorations. The guarded prognosis associated with extensive posterior resin composite restorations is acknowledged; nevertheless this technique remains a realistic option for those financially compromised patients who request tooth-colored restorations.

Whole blood coagulation analyzers

Whole blood Coagulation analyzers (WBCAs) are widely used point-of-care (POC) testing devices found primarily in cardiothoracic surgical suites and cardia catheterization laboratories. Most of these devices can perform a number of coagulation tests that provide information about a patient's blood clotting status. Clinicians use the results of the WBCA tests, which are available minutes after applying a blood sample, primarily to monitor the effectiveness of heparin therapy--an anticoagulation therapy used during cardiopulmonary bypass (CPB) surgery, angioplasty, hemodialysis, and other clinical procedures. In this study we evaluated five WBCAs from four suppliers. Our testing focused on the applications for which WBCAs are primarily used: Monitoring moderate to high heparin levels, as would be required, for example, during CPB are angioplasty. For this function, WCBAs are typically used to perform an activated clotting time (ACT) test or, as one supplier refers to its test, a heparin management test (HMT). All models included in this study offered an ACT test or an HMT. Monitoring low heparin levels, as would be required, for example,during hemodialysis. For this function, WBCAs would normally be used to perform either a low-range ACT (LACT) test or a whole blood activated partial thromboplastin time (WBAPTT) test. Most of the evaluated units could perform at least one of these tests; one unit did not offer either test and was therefore not rated for this application. We rated and ranked each evaluated model separately for each of these two applications. In addition, we provided a combined rating and ranking that considers the units' appropriateness for performing both application. We based our conclusions on a unit's performance and humans factor design, as determined by our testing, and on its five-year life-cycle cost, as determined by our net present value (NPV) analysis. While we rated all evaluated units acceptable for each appropriate category, we did identify some significant differences that enabled us to rank the units in order of preference. We have included a Selection, Purchasing, and use guide at the end of this study to help facilities identify the unit that will best meet their needs.

Determination of the International Sensitivity Index of a new near-patient testing device to monitor oral anticoagulant therapy--overview of the assessment of conformity to the calibration model

A key issue for the reliable use of new devices for the laboratory control of oral anticoagulant therapy with the INR is their conformity to the calibration model. In the past, their adequacy has mostly been assessed empirically without reference to the calibration model and the use of International Reference Preparations (IRP) for thromboplastin. In this study we reviewed the requirements to be fulfilled and applied them to the calibration of a new near-patient testing device (TAS, Cardiovascular Diagnostics) which uses thromboplastin-containing test cards for determination of the INR. On each of 10 working days citrated whole blood and plasma samples were obtained from 2 healthy subjects and 6 patients on oral anticoagulants. PT testing on whole blood and plasma was done with the TAS and parallel testing for plasma by the manual technique with the IRP CRM 149S. Conformity to the calibration model was judged satisfactory if the following requirements were met: (i) there was a linear relationship between paired log-PTs (TAS vs CRM 149S); (ii) the regression line drawn through patients data points, passed through those of normals; (iii) the precision of the calibration expressed as the CV of the slope was <3%. A good linear relationship was observed for calibration plots for plasma and whole blood (r = 0.98). Regression lines drawn through patients data points, passed through those of normals. The CVs of the slope were in both cases 2.2% and the ISIs were 0.965 and 1.000 for whole blood and plasma. In conclusion, our study shows that near-patient testing devices can be considered reliable tools to measure INR in patients on oral anticoagulants and provides guidelines for their evaluation.

Does the platelet-activated clotting test (HemoSTATUS) predict blood loss and platelet dysfunction associated with cardiopulmonary bypass?

Platelet dysfunction is a major cause of bleeding after cardiopulmonary bypass (CPB). No timely, simple, point-of-care determinant of platelet function is available for clinical use. Adding platelet-activating factor to conventional activated clotting time methods (platelet-activated clotting test [PACT]) (HemoSTATUS; Medtronic, Inc., Parker, CO) produces rapid results (<3 min) and may yield a measure of platelet responsiveness and whole blood procoagulant activity. Blood samples were drawn for PACT, platelet count, prothrombin time, activated partial thromboplastin time, and thromboelastogram (TEG) from 200 patients undergoing cardiac surgery. The PACT significantly decreased from the baseline to postprotamine time interval (P < 0.001). The PACT correlated with 4-h mediastinal blood loss (r = -0.30, P = 0.014). The TEG maximum amplitude also correlated with 4-h mediastinal blood loss (r = -0.32, P = 0.003). The PACT had a sensitivity and specificity comparable to routine laboratory coagulation tests in predicting blood loss. The TEG maximum amplitude, however, was more predictive than both the PACT and routine coagulation tests in this respect. The PACT may be a useful indicator of platelet responsiveness or whole blood procoagulant activity, but we did not find it superior to other tests of coagulation function for predicting excessive blood loss after CPB.

Respiratory consultant: a hand-held computer-based system for oxygen therapy and critical care medicine

The assessment of respiratory system performance may involve issues such as pulmonary gas exchange, respiratory mechanics, oxygen transport and other factors. This paper describes an MS-DOS program called Respiratory Consultant that was designed for use with a hand-held MS-DOS computer, but can also run under Windows 3.1 and Windows 95 if desired. Respiratory Consultant performs a number of computational tasks potentially appropriate to respiratory care in the ICU and elsewhere. These include: predicted arterial oxygen tension from age, interconversion of oxygen tension and saturation, calculation of gas exchange indices and oxygen transport parameters, dead-space estimation, and pulmonary function test interpretation. Respiratory Consultant is freeware that will run easily on most IBM-compatible PCs and may be downloaded from the Internet.

Rapid bedside coronary angiography with a portable fluoroscopic imaging system

The ability to perform coronary angiography rapidly at the bedside has multiple potential applications. This study was designed to determine whether a novel portable angiographic system (OEC Medical Systems, series 9600, Salt Lake City, Utah) is capable of producing high-quality angiograms. In 29 patients (70 vessels) undergoing elective catheterization in a conventional fixed laboratory (Siemens HICOR, Erlangen, Germany), we compared images obtained with the portable system to those from conventional fixed system. The portable system was 100% accurate in detecting both insignificant narrowing as well as significant stenoses (> 50% narrowing). There was complete concordance between systems for lesion location, TIMI flow, and collaterals. Thirty-two stenoses were analyzed in detail. Both quantitative and qualitative percent stenosis demonstrated similar value for lesion severity with both systems (R = 0.95, Kappa = 0.77, P < 0.001, respectively). Accuracy of lesion morphology by the portable system was similar to the fixed system (calcification 80%, eccentricity 92%). These findings demonstrate that a portable imaging system can produce high-quality coronary angiograms.

Joining forces to improve point-of-care testing

Point-of-care (POC) testing takes a "laboratory" test directly to the patient's bedside. Although bedside testing is not new, the compliance standards are relatively new. Regulations ensure that all personnel are trained to properly perform the test. The central laboratory and nursing of this hospital merge the best skills of both units to create a successful POC testing program.

Blood glucose determination: point of care testing

Mechanisms for point of care glucose determinations have changed significantly since first introduced approximately 20 years ago. Such tests are now commonly done in acute and chronic care hospitals, as well as in physicians' offices and patients' homes. Although basically reliable, there are a number of potential problems with glucose determination by these methods that may not be considered by physicians interpreting these tests. This is a brief review of such problems, especially in the acute care setting.

An erbium:YAG laser to obtain capillary blood samples without a needle for point-of-care laboratory testing

BACKGROUND

Needlestick injury poses an occupational hazard to health care workers that will increase with the increasing availability of point-of-care testing using capillary blood obtained with a lancet.

OBJECTIVES

To demonstrate the safety and efficacy of a portable pulsed erbium:yttrium-aluminum-garnet (Er:YAG) laser in obtaining a blood sample from patients in a clinical setting and to determine whether the laser radiant energy alters the level of various components of blood, resulting in misleading laboratory results.

DESIGN

Comparison of laboratory values of blood samples obtained with the laser and conventional lancet and comparison of patient and user preferences by questionnaire.

PATIENTS AND METHODS

One hundred patients with diabetes mellitus attending a diabetes clinic were randomized to have capillary blood sampling from the fingertip performed either by the laser or a conventional lancet first, then with the other device.

MAIN OUTCOME MEASURES

A comparison of pain, healing, hematocrit, and glycosylated hemoglobin (HbAlc), blood urea nitrogen, sodium, potassium, bicarbonate, and glucose levels.

RESULTS

Adequate blood was obtained with both devices 97% of the time. Blood flow was greater with the laser perforation, resulting in higher operator preference. Although patients felt greater pain and experienced slower healing with the laser, these were not serious problems. Modification of the laser energy output led to a reduction in pain. Possibly owing to hemolysis, the potassium level in the blood obtained with the laser was significantly elevated and unsuitable for clinical decision making in many cases. None of the other measurements were similarly affected.

CONCLUSIONS

We conclude that the laser device has the potential to obtain a blood sample for routine tests without a needle. This needle-free method will decrease the risk of bloodborne infections caused by needlestick injuries and thus lead to considerable cost savings and public health advantages. Further work is needed to alter the laser energy so that hemolysis can be decreased, thus enabling a more reliable potassium estimation.

[The diagnosis of deep venous thromboses of the leg using a new rapid test (SimpliRED)]

PURPOSE

Evaluation of sensitivity and specificity of a bed-side test in the diagnosis of deep-vein thrombosis compared to contrast phlebography.

METHODS

122 patients, referred for phlebography, underwent bedside testing (SimpliRED) for detection of deep vein thrombosis. Contrast phlebography was confirmed immediately afterwards. SimpliRED provides a clearly visible agglutination of the patient's red blood cells in the presence of elevated levels of crosslinked fibrin derivatives (D-dimer) in the sample, being specific for fibrin breakdown.

RESULTS

In 37 (30.3%) patients deep vein thrombosis could be confirmed. An abnormal D-dimer test was found in 35 of the 37 patients with thrombosis (sensitivity: 94.6%). Two patients who had not been identified by agglutinin testing, showed an isolated calf thrombosis in small muscle veins (< 2 cm in diameter) not requiring treatment. 55 of 85 patients without thrombosis in phlebography were stated correctly by SimpliRED (specificity: 64.7%).

CONCLUSION

All thrombotic disorders in the leg with the need for further treatment were identified correctly. SimpliRED is a very sensitive test with moderate specificity in the diagnosis of deep vein thrombosis. Therefore, further invasive testing is needed only in such patients where the D-dimer test is abnormal. A false positive result of the bed-side test may be non-specific or due to elevated levels of fibrin split products, if the coagulation system is activated in several other conditions.

Technologies' impact on healthcare facilities

Technologies common to other industries are gradually being utilized in healthcare. Heavily led by information technology, providers are using technology to increase efficiency, improve customer service and better integrate and streamline business and clinical processes. These changes are gradually making many hospitals' physical facilities obsolete, requiring substantial changes or upgrades. Eight examples are illustrated where technology is changing the requirements in facility utilization, design and construction.

A rapid qualitative assay to detect circulating endotoxin can predict the development of multiorgan dysfunction

OBJECTIVE

To determine whether a rapid qualitative assay for the detection of circulating endotoxin (SimpliRED Endotoxin Test [SRE]; AGEN, Inc; Brisbane, Australia) can predict the occurrence of multiorgan dysfunction and hospital mortality. To compare the SRE to the limulus amebocyte lysate (LAL) assay as a predictor of clinical outcomes.

DESIGN

Prospective, blinded, single-center study.

SETTING

Medical ICU of Barnes-Jewish Hospital, St. Louis, a university-affiliated teaching hospital.

PATIENTS

Included in the study were 265 adult patients requiring medical ICU admission.

INTERVENTIONS

Daily collection of blood samples.

MEASUREMENTS AND RESULTS

Daily detection for the presence of endotoxin in blood during intensive care and assessment for the development of multiorgan dysfunction (ie, an organ system failure index >2) or death. On ICU day 1, 55 (20.8%) patients had circulating endotoxin detected by the SRE. On ICU day 2, 29 of the 143 (20.3%) patients remaining in the ICU had a positive SRE. The development of multiorgan dysfunction was significantly greater among SRE-positive patients (44.8%) compared to SRE-negative patients (21.9%) on ICU day 2 (p=0.013). Multiple logistic regression analysis identified a positive SRE on ICU day 2 (adjusted odds ratio, 4.1; 95% confidence interval, 2.5 to 6.8; p=0.006) as being independently associated with the development of multiorgan dysfunction. A positive SRE test was not predictive of hospital mortality. Direct quantitative measurement of the concentration of circulating endotoxin using the LAL assay was not associated with either the development of multiorgan dysfunction or hospital mortality (p>0.1).

CONCLUSIONS

Our preliminary data suggest that a bedside assay to qualitatively detect circulating endotoxin is predictive of the development of multiorgan dysfunction among patients admitted to a medical ICU. The rapid detection of circulating endotoxin could be useful for stratifying patients into various risk categories for the development of multiorgan dysfunction.

Digital imaging and teledermatology: educational and diagnostic applications of a portable digital imaging system for the trainee dermatologist

Teledermatology is no longer a futuristic curiosity; several general practices across the UK are now preparing to be electronically linked to other medical services for the purposes of referral and telediagnosis. Further, digital imaging in dermatology has been the subject of considerable research in recent years, largely because of its application to telemedicine. Indeed in the UK, geographically isolated general practices in North Powys have already demonstrated the effective delivery of dermatological expertise through a video-conferencing link to a consultant dermatologist at Aberystwyth Hospital, thereby reducing the need for patients or the consultant to travel long distances.

Disease management

Disease management efforts are becoming an important competitive strategy for providers and managed care plans alike. More than ever, purchasers of care want value from their health care dollars, and integrated delivery systems want to better coordinate care. Information technology will be crucial in implementing disease management programs.

Performance of asynchronous transfer mode (ATM) local area and wide area networks for medical imaging transmission in clinical environment

Asynchronous transfer mode (ATM) technology emerges as a leading candidate for medical image transmission in both local area network (LAN) and wide area network (WAN) applications. This paper describes the performance of an ATM LAN and WAN network at the University of California, San Francisco. The measurements were obtained using an intensive care unit (ICU) server connecting to four image workstations (WS) at four different locations of a hospital-integrated picture archiving and communication system (HI-PACS) in a daily regular clinical environment. Four types of performance were evaluated: magnetic disk-to-disk, disk-to-redundant array of inexpensive disks (RAID), RAID-to-memory, and memory-to-memory. Results demonstrate that the transmission rate between two workstations can reach 5-6 Mbytes/s from RAID-to-memory, and 8-10 Mbytes/s from memory-to-memory. When the server has to send images to all four workstations simultaneously, the transmission rate to each WS is about 4 Mbytes/s. Both situations are adequate for radiologic image communications for picture archiving and communication systems (PACS) and teleradiology applications.

ED's paradigm shift cuts costs, improves quality

WHERE

The emergency department of Parkview Memorial Hospital, a 519-bed, VHA-affiliated acute care facility in Ft. Wayne, IN.

PROBLEM

The need to shorten waiting time, improve patient satisfaction, and reduce costs while maximizing the potential of a $9 million renovation. Also, the need to address emergent and urgent care with different processes and operations.

SOLUTIONS

Through benchmarking, staff initiated bedside registration on laptop computers; cross-trained and restructured to drastically reduce overtime and salary expenses while adding FTEs; and provided tools for training physicians and nurses to handle patients.

RESULTS

Wait time to see a doctor has declined by two-thirds. Cost per visit has dropped 12%, saving the department more than $422,000 in 1996. Satisfaction scores have almost doubled to 86%.

Thoughts on quality-control systems: a laboratorian's perspective

State-of-the-art prospective quality-control systems entail the use of medically relevant, analyte-specific quality control limits. With analyte-specific limits broader than those generally used in the clinical laboratory, there will be fewer false rejections, fewer unnecessary reanalyses, and shorter delays in run reporting. If the analyte-specific limits are narrower than those used in the laboratory, more errors will be detected, but the user is at risk of identifying errors over which s/he and the manufacturer have little control. The use of various patient data quality-control algorithms is described. Conservatism is stressed in adopting manufacturers' guidelines for surrogate, nondestructive quality-control testing. A simple, optimized approach is suggested for the systematic retrospective review of proficiency data. Finally, an approach is presented for converting from older, previously accepted quality control procedures to more efficient analyte-specific quality control.

Whole-blood immunoassay (SimpliRED) versus plasma immunoassay (NycoCard) for the diagnosis of clinically suspected deep vein thrombosis

BACKGROUND

The level of D-dimer in the blood reflects the level of lysed, cross-linked fibrin, and is a useful diagnostic marker in patients with clinically suspected deep vein thrombosis (DVT). In this study, two assays for the measurement of D-dimer levels were compared: the new, whole-blood immunoassay, SimpliRED, which can be performed at the patient's bedside in two minutes; and the plasma immunoassay, NycoCard.

PATIENTS AND METHODS

D-dimer levels were determined using these two techniques in 108 patients with clinically suspected DVT. To ascertain or rule out the diagnosis of DVT compression ultrasonography using a colour coded Duplex instrument was done. 8 doubtful cases were diagnosed by ascending phlebography. By these procedures DVT was confirmed in 33 patients and ruled out in the remaining 75 cases.

RESULTS

The SimpliRED assay exhibited a sensitivity of 1.0 (CI 0.89-1.0) and a specificity of 0.75 (CI 0.63-0.84); negative predictive value 1.0 (CI 0.94-1.0), positive predictive value 0.63 (CI 0.49-1.0). By contrast, the NycoCard assay displayed a sensitivity of 0.85 (CI 0.68-0.95) and a specificity of 0.65 (CI 0.53-0.76); negative predictive value 0.91 (CI 0.80-0.97), positive predictive value of 0.52 (CI 0.38-0.66).

CONCLUSION

The results show that the SimpliRED assay is a valuable tool in the diagnosis of clinically suspected DVT, especially when laboratory facilities are not accessible.

Accurate and precise isotope dilution mass spectrometry method for determining glucose in whole blood

An accurate and precise method to determine glucose concentration in whole blood is presented. The method, based on isotope dilution gas chromatography-mass spectrometry (ID GC-MS), was developed to be used as a Reference Method for determining glucose concentration in capillary or venous whole blood. Blood samples and standards are pipetted manually with "microcap" micropipettes, which makes it possible to collect samples even at the patient's bedside. Glucose is quantified as its aldononitrile pentaacetate. [13C6]Glucose is used as an internal standard. Assay of Seronorm and Pathonorm L and H controls by ID GC-MS gave within-run CVs of 0.66%, 0.96%, and 0.92%, respectively. For whole blood with glucose concentrations in the low, normal, and high ranges, the within-run CVs were 1.27%, 0.91%, and 0.78%, respectively. The between-run CV for glucose calculated from 36 separate single analyses of Seronorm was 1.44%. In an accuracy assessment test of the HemoCue blood glucose analyzer, 140 capillary blood samples were measured in parallel after split-sampling. For all samples the HemoCue analyzer results had a mean bias of +2.0% compared with the ID GC-MS results.

Direct-indirect resin restoration: a case report of acceptable compromise

A specifically-formulated, fast-setting die material has made it possible to fabricate and insert indirect resin restorations in one appointment. This case report describes a modification to an existing, newly-released one-appointment resin inlay-onlay technique for the chairside fabrication of indirect composite resin restorations. Using this technique, large occlusal load-bearing extracoronal composite resin restorations can be constructed economically. Although the prognosis for extensive posterior composite resin restorations remains guarded, the modified procedure is a realistic option for financially-compromised patients who request tooth colored restorations.

Evaluation of chest pain in the emergency department

The evaluation of chest pain in the emergency setting should be systematic, risk based, and goal driven. An effective program must be able to evaluate all patients with equal thoroughness under the assumption that any patient with chest pain could potentially be having an MI. The initial evaluation is based on the history, a focused physical examination, and the ECG. This information is sufficient to categorize patients into groups at high, moderate, and low risk. Table 14 is a template for a comprehensive chest-pain evaluation program. Patients at high risk need rapid initiation of appropriate therapy: thrombolytics or primary angioplasty for the patients with MIs or aspirin/heparin for the patients with unstable angina. Patients at moderate risk need to have an acute coronary syndrome ruled in or out expediently and additional comorbidities addressed before discharge. Patients at low risk also need to be evaluated, and once the likelihood of an unstable acute coronary syndrome is eliminated, they can be discharged with further evaluation performed as outpatients. Subsequent evaluation should attempt to assign a definitive diagnosis while also addressing issues specific to risk reduction, such as cholesterol lowering and smoking cessation. It is well documented that 4% to 5% of patients with MIs are inadvertently missed during the initial evaluation. This number is surprisingly consistent among many studies using various protocols and suggests that an initial evaluation limited to the history, physical examination, and ECG will fail to identify the small number of these patients who otherwise appear at low risk. The solution is to improve the sensitivity of the evaluation process to identify these patients. It appears that more than simple observation is required, and at the present time, no simple laboratory test can meet this need. However, success has been reported with a number of strategies including emergency imaging with either radionuclides such as sestamibi or echocardiography. Early provocative testing, either stress or pharmaceutic, may also be effective. The added value of these tests is only in their use as part of a systematic protocol for the evaluation of all patients with acute chest pain. The initial evaluation of the patient with chest pain should always consider cardiac ischemia as the cause, even in those with more atypical symptoms in whom a cardiac origin is considered less likely. The explicit goals for the evaluation of acute chest pain should be to reduce the time to treat MIs and to reduce the inadvertent discharge of patients with occult acute coronary syndromes. All physicians should become familiar with appropriate risk stratification of patients with acute chest pain. Systematic strategies must be in place to assure rapid and consistent identification of all patients and the expedient initiation of treatment for those patients with acute coronary syndromes. These strategies should include additional methods of identifying acute coronary syndromes in patients initially appearing as at moderate or low risk to assure that no unstable patients are discharged. All patients should be followed up closely until the cardiovascular evaluation is completed and, when possible, a definitive diagnosis is determined. Finally, this must be done efficiently, cost-effectively, and in a manner that will result in an overall improvement in patient care.