Cardiac output measurement by the thermodilution method: An in vitro test of accuracy of three commercially available automatic cardiac output computers

Objective To describe the accuracy and the reproducibility of the thermodilution flow measurements obtained using 3 commercially available cardiac output computers commonly used in intensive care units.Design An experimental in vitro study. Twelve different values of control flow (Qctr) were measured (Qmsr) using 3 different cardiac output computers (Abbott Critical Care System, Oximetrix 3 SvO₂/CO Computer, Baxter Oximeter/Cardiac Output Computer SAT-1^TM; American Edwards Laboratories, 9520 A Cardiac Output Computer). Standard equipment and techniques were employed, taking account of the specific weight and heat of warm water relative to blood. In addition, separate sets of measurements were performed in order to investigate the effect on Qmsr of some variables which may influence the indicator loss (time for injection, depth of immersion of the catheter, temperature of the injected fluid).Setting Our laboratory, inside the intensive care unit.Measurements and results The analysis of the linear regression of Qmsr versus Qctr (r values between 0.992 and 0.984; residual standard deviation values comprised between 0.24 and 0.49 l/min; intercepts and slopes not significantly different from identity line), the values of the percentage errors (PE=[Qctr–Qmsr]·100/Qctr; PE mean values 7.9, 5.0 and 13.1), and those of the coefficients of variability (CV=standard deviation mean value, %; CV mean values 5.4, 5.8 and 4.6), show a good level of accuracy and reproducibility of the measurements. Our data confirm previously reported results. Furthermore, the cumulative effect of variables capable of influencing the indicator loss, even if corrected according to the calculation constant the manufacturers provide, was found to result in statistically significant changes of Qmsr.Conclusion The accuracy and reproducibility of the automatic cardiac computers tested is sufficient for practical clinical purpose. It may also depend on the modality of injection of the cooling bolus, which may significantly influence the effective indicator losses.     

Two Types of Health Care Systems and Their Influence on the Introduction of Perinatal Care: An Epidemiological Twin Model in Berlin from 1950 to 1990

Objectives: When perinatal medicine emerged as a new medical discipline in the 1960s, Berlin was as one of the world's leading centers. During that time, the city was separated into two parts, each fostering its own health care system. After the destruction of the Berlin Wall, it was possible to speak with the citizens of East Berlin and to access their database systems. This created the singular opportunity to objectively compare the development of perinatal care in both parts of Berlin. Methods: Rates of maternal, perinatal, and infant mortality as well as the rate of preterm deliveries were evaluated over time and between East and West Berlin. The timing of introduction of 20 specific perinatal interventions was evaluated across 18 hospitals with more than 500 deliveries (11 in West Berlin and 7 in East Berlin). Interviews were conducted with 100 gynecologists, 100 midwives, and 100 women who had recently delivered their first child from each side of the city regarding their opinions of the importance of these interventions for the quality of perinatal medicine and how they would distribute a budget to improve maternity care. Results: Maternal, perinatal, and infant mortality decreased in both parts of Berlin until 1990 (p<0.0001), without significant differences between East and West Berlin, though the preterm delivery rate was slightly lower in East Berlin compared with West Berlin (p<0.06). Some new clinical techniques and treatments—such as cardiotocography, ultrasound, tocolytic therapy, and peridural anesthesia—were introduced earlier in West Berlin. In contrast, certain public health measures—such as maternal transport, screening programs for diabetes, and support of breastfeeding—were introduced much earlier in East Berlin. There were significant differences between the beliefs of gynecologists, midwives, and mothers in East and West Berlin. In general, citizens of East Berlin were more enthusiastic about technological medical advances, whereas citizens of West Berlin were more supportive of public health and alternative methods. In addition, there were significant differences between female and male physicians in their beliefs about how to improve health care, regardless of whether they resided in East or West Berlin. Conclusions: The results of this study may serve as a basis for reflection on how different social circumstances and health care policies can influence the improvement of maternal and child health care.     

Public health services in Bangladesh with special reference to systems and trends of vital statistics

Health is one of the basic requirements for improvement in the quality of life. Since Bangladesh became independent, a policy for providing essential minimum health care to all has been actively pursued. An overview of Public Health Services in Bangladesh is presented in terms of: (1) a profile of the country, (2) an overview of public health, (3) medical care, and (4) environmental health. Under each of these headings observations are included on recent trends based upon relevant data and information. Finally the authors describe the importance of (1) promotion of health care and planning at the national, divisional, local, and community levels, (2) promotion of medical services at all levels, and (3) effective decentralization of health services to enhance the services of health facilities.     

DNA typing in cases of blood chimerism

A chimera is an organism whose cells derive from two or more distinct zygote lineages. and therefore two different blood cell populations circulate in one individual. To point out the potential pitfalls in forensic analysis, a set of triplets (a girl and two boys) who revealed blood chimerism was investigated with four STR systems using PCR. The results indicated that a DNA profile based on DNA extracted from blood can lead to a false determination because the band pattern of each triplet contained a mixture of the original genotype and the genotype of the siblings. Additional investigations on biological materials other than blood must be made in order to find out the real genetic characteristics of each child. Received: 17 July 1998 / Received in revised form: 27 November 1998     

A new method of STR interpretation using inferential logic -development of a criminal intelligence database

Abstract A short tandem repeat (STR) system consisting of seven multiplexed loci has recently been introduced in the UK to support a National strategy to create large DNA databases for criminal intelligence purposes. The process uses automated sequencers, employing dye-labelled primers. Identification of tetrameric loci such as HUMTH01 are straightforward. Sizing windows are estimated by running a series of control allelic ladders on several gels and unknown samples are designated if they fall within a defined window. However, utilisation of complex STRs (eg. D21 S 11) characteristically have common variants which differ by just 2 bp. In addition, rare alleles are encountered which may differ by just 1 by from a common variant. To assist with the identification of alleles, we have introduced a series of allelic ladders, so that direct comparisons with unknown samples can be made on the same gel. To designate an allele, it should be within 0.5 by of an allelic ladder marker. Not all alleles (in particular rare alleles) can be included within an allelic ladder, however their expected positions can be easily calculated by reference to existing alleles in the ladder. Measurement of band shift is also a useful diagnostic tool. A series of guidelines are described to enable reliable allelic identification. These guidelines can be converted into computer programmes, which form the basis of an expert system.     

Stepwise development of a clinical expert system in rheumatology

Summary The evaluation of computer expert systems, a promising diagnostic tool for future application in clinical medicine, is of great importance. We present here the evaluation of our expert system, RHEUMA. It is stressed, that repeated retrospective testing and updating of an expert system and its subsequent repeated assessment in clinical use and surroundings is mandatory. This increases the diagnostic accuracy of the system. For our system this is demonstrated under three separate conditions. In the first study the information available for the computer system (mainframe) came from medical histories only. Here an error rate of about 25% — similar to that of physicians themselves using the same information — was observed in 358 outpatients, compared to the final diagnoses of physicians also relying solely on information from medical histories. In a second step a completely new system on a personal computer was developed with all relevant diagnostic information. The error rate of this system (0.4%) was much too optimistic because the knowledge base was changed during the study, affecting about 30% of the 282 prospectively recruited outpatients. In a third step the efficacy of the expert system was tested in an additional hospital without the diagnostic involvement of the first testing clinic. The error rate of the system without changing the knowledge base reached 11% in 51 outpatients in this rheumatology clinic. This result reflects the diagnostic accuracy of the system today. Its ability to specify the same diagnoses which clinical experts reached approached 90%. Considerable time is needed for such prospective testing, with repeated updating of the knowledge base — in our case for both the two systems and field studies of 2 years each. Further prospective field testing with physicians not specialized in rheumatology and with a larger number of patients is necessary before the system can be used in clinical routine.Dedicated to Prof. Dr. N. Zöllner on the occasion of his 70th birthday     

Multidetector single-photon emission tomography: are two (or three or four) heads really better than one?

Today, almost every camera sold, with the exception of mobile systems, is single-photon emission tomography-capable. The atest technical development is the so-called multidetector systems. This article reviews the development and current and potential clinical role of these multidetector systems, with particular emphasis on multicamera systems. The utility of multidetector systems is considered in the context of an image's signal-to-noise ratio, including its effect on diagnostic or quantitative accuracy. The potential for multidetector systems to increase the signal-to-noise ratio is discussed, as are other potential benefits. Finally, advice on an approach to equipment selection is provided.     

Hemispherectomy — 25 years later — findings and concepts

Summary In the first part the case of a then 27 year old female patient with right-sided infantile spastic hemiplegia after left-sided porencephaly is described, in whom hemispherectomy was performed 25 years ago. The postoperative state and the development are described as well as the social outcome and the present neurological status. A computer-tomogram shows the actual state of the brain.The second part is devoted to a scientific discussion of the supplementary motility after pyramidal lesions which is defined as the action of descending subcortico-spinal pathways starting probably in the mesencephalon, whereas an ipsilateral pathway is unlikely. Comparative neurological experiments serve to support such a concept as well as similar observations in traumatic cerebral lesions in man. In the light of the far more skilled motility in cerebral lesions of the young as well as the possibility of a shift of neuropsychological functions of the dominant to the contralateral hemisphere in children up to the age of 8–10 the possibility is discussed that plasticity — the concept of Albert Bethe — could form the mechanism of auxiliary function.Furthermore the surprising sensory performances in some of the patients with hemispherectomy are emphasized and the possibilities of anipsilateral substratum are discussed; however, this contrasts with the concepts formulated for the auxiliary motility after pyramidal lesions. Clarification of these problems will probably follow only after further experimental work.

---

Zusammenfassung Im ersten Teil der Arbeit wird der Fall einer damals 27-jährigen Patientin beschrieben, die eine rechtsseitige infantile spastische Hemiplegie nach linksseitiger Porencephalie hatte. Bei ihr war 25 Jahre zuvor eine Hemisphärektomie durchgeführt worden. Der postoperative klinische Status und die Entwicklung der Syndrome wird beschrieben und über die soziale Situation berichtet. Schließlich wird der derzeitige neurologische Status genau wiedergegeben. Erstmalig zeigt ein Computer-Tomogramm den Zustand des Hirns nach diesem Zeitraum.Im zweiten Teil der Arbeit wird die Entstehung der Ersatz-Motilität diskutiert, die als eine Aktion deszendierender subkortiko-spinaler Bahnen definiert wird, die wahrscheinlich vom Mittelhirn ihren Ausgang nehmen, während die Tätigkeit ipsilateraler Systeme für unwahrscheinlich gehalten wird. Vergleichende Tierexperimente am Hirn unterstützen eine solche Auffassung, ebenso wie auch die Beobachtung bei umschriebenen Hirnverletzungen des Menschen.Dann wird die Möglichkeit von Ersatzfunktionen durch Plastizität diskutiert — ein Begriff von Albert Bethe. Dies erscheint im Lichte vieler Beobachtungen wichtig, da die Ersatz-Motilität bei Hirnläsionen junger Menschen sehr viel höhere Geschicklichkeit ermöglicht als bei Läsionen von Älteren; weiter ist zu beachten, daß neuropsychologische Funktionen bei einer Hirnläsion vor dem 8. bis 10. Lebensjahr von einer dominanten Hemisphäre noch auf die andere Seite verlegt und dort lokalisiert werden können. Schließlich wird bei diesen Patienten auf die erstaunlichen Fähigkeiten der sensiblen Systeme nach Hemisphärektomie hingewiesen und hier die Möglichkeit eines ipsilateralen anatomischen Apparates diskutiert. Jedoch können bei der Sensibilität so genaue funktionell-morphologische Vorstellungen noch nicht formuliert werden, wie sie sich z. Zt. schon für die Ersatz-Motilität nach Pyramidenbahnläsion ergeben. Erst genauere Experimente im Tierversuch können weitere Aufklärung bringen.

     

Can a community development model be used for health programmes in an industrialized country?

Injury resulting from accident is a serious public health problem in Sweden, as it is in the rest of the world. Theoretically, almost all incidents can be prevented. However, in practice, injury-prevention is a complex problem. A community-level intervention programme for prevention of accidents was developed in the municipality of Sollentuna, Stockholm County. The primary strategy has been to involve the community through representatives as well as through local organizations and groups. Project organization has been built up in cooperation with the municipal primary health-care department, local authorities, voluntary organizations and citizen agencies. A common opinion is that it is the actual process in a community programme which is important, that alters the type of involvement from a ‘top-down’ to a ‘bottom-up’ approach. Can a local community take over responsibility for running such a programme which has been initiated by an external authority or organization? We think that, at least for Swedish circumstances, the community development approach is far too optimistic in its expectation that community members should and can stay actively involved in programme decisions. Based on our experience, it does not seem possible to maintain a broad self-sustained programme solely with input from community members.