Meikirch model: new definition of health as hypothesis to fundamentally improve healthcare delivery

The unrelenting rise in healthcare costs over the past 50 years has caused policymakers to respond. Their reactions have led to a gradual economic transformation of medicine. As a result, detailed billing, quality controls, financial incentives, savings targets and digitalisation are now putting increasing pressures on the nursing and medical staff. In addition, the humanity of care of the patient–doctor and/or patient–nurse interactions has been cast aside to a great extent. Therefore, the immaterial side of care has been neglected or even removed from these relationships. These changes are now perceived as intolerable by most health workers and patients. Yet healthcare costs are still rising. This paper presents a hypothesis that should enable healthcare systems to respond more effectively. It proposes the introduction of the Meikirch model, a new comprehensive definition of health. The Meikirch model takes human nature fully into account, including health and disease. The inclusion of the individual potentials, the social surroundings and the natural environment leads to the concept of health as a complex adaptive system (CAS). Care for such a definition of health requires medical organisations to change from top–down management to bottom–up leadership. Such innovations are now mature and ready for implementation. They require a long-term investment, a comprehensive approach to patient care and new qualifications for leadership. The Meikirch model reads: ‘To be healthy a human individual must be able to satisfy the demands of life. For this purpose, each person disposes of a biologically given and a personally acquired potential, both of which are closely related to the social surroundings and the natural environment. The resulting CAS enables the individual to unfold a personal identity and to develop it further until death. Healthcare has the purpose to empower each individual to fully realize optimal health’.This hypothesis postulates that the new definition of health will further develop healthcare systems in such a way that better health results at lower costs.

Better and fulfilling healthcare at lower costs: The need to manage health systems as complex adaptive systems

Rising healthcare costs are major concerns in most high-income countries. Yet, political measures to reduce costs have so far remained futile and have damaged the best interests of patients and citizen. We therefore explored the possibilities to analyze healthcare systems as a socially constructed complex adaptive system (CAS) and found that by their very nature such CAS tend not to respond as expected to top-down interventions. As CAS have emergent behaviors, the focus on their drivers - purpose, economy and behavioral norms - requires particular attention. First, the importance of understanding the purpose of health care as improvement of health and its experience has been emphasized by two recent complementary re-definitions of health and disease. The economic models underpinning today's healthcare - profit maximization - have shifted the focus away from its main purpose. Second, although economic considerations are important, they must serve and not dominate the provision of healthcare delivery. Third, expected health professionals' behavioral norms - to first consider the health and wellbeing of patients - have been codified in the universally accepted Declaration of Geneva 2017. Considering these three aspects it becomes clear that complex adaptive healthcare systems need mindful top-down/bottom-up leadership that supports the nature of innovation for health care driven by local needs. The systemic focus on improving people's health will then result in significant cost reductions.

Health and Disease-Emergent States Resulting From Adaptive Social and Biological Network Interactions

Health is an adaptive state unique to each person. This subjective state must be distinguished from the objective state of disease. The experience of health and illness (or poor health) can occur both in the absence and presence of objective disease. Given that the subjective experience of health, as well as the finding of objective disease in the community, follow a Pareto distribution, the following questions arise: What are the processes that allow the emergence of four observable states-(1) subjective health in the absence of objective disease, (2) subjective health in the presence of objective disease, (3) illness in the absence of objective disease, and (4) illness in the presence of objective disease? If we consider each individual as a unique biological system, these four health states must emerge from physiological network structures and personal behaviors. The underlying physiological mechanisms primarily arise from the dynamics of external environmental and internal patho/physiological stimuli, which activate regulatory systems including the hypothalamic-pituitary-adrenal axis and autonomic nervous system. Together with other systems, they enable feedback interactions between all of the person's system domains and impact on his system's entropy. These interactions affect individual behaviors, emotional, and cognitive responses, as well as molecular, cellular, and organ system level functions. This paper explores the hypothesis that health is an emergent state that arises from hierarchical network interactions between a person's external environment and internal physiology. As a result, the concept of health synthesizes available qualitative and quantitative evidence of interdependencies and constraints that indicate its top-down and bottom-up causative mechanisms. Thus, to provide effective care, we must use strategies that combine person-centeredness with the scientific approaches that address the molecular network physiology, which together underpin health and disease. Moreover, we propose that good health can also be promoted by strengthening resilience and self-efficacy at the personal and social level, and via cohesion at the population level. Understanding health as a state that is both individualized and that emerges from multi-scale interdependencies between microlevel physiological mechanisms of health and disease and macrolevel societal domains may provide the basis for a new public discourse for health service and health system redesign.

Will the Meikirch Model, a New Framework for Health, Induce a Paradigm Shift in Healthcare?

Over the past decades, scientific medicine has realized tremendous advances. Yet, it is felt that the quality, costs, and equity of medicine and public health have not improved correspondingly and, both inside and outside the USA, may even have changed for the worse. An initiative for improving this situation is value-based healthcare, in which value is defined as health outcomes relative to the cost of achieving them. Value-based healthcare was advocated in order to stimulate competition among healthcare providers and thereby reduce costs. The approach may be well grounded economically, but in the care of patients, "value" has ethical and philosophical connotations. The restriction of value to an economic meaning ignores the importance of health and, thus, leads to misunderstandings. We postulate that a new understanding of the nature of health is necessary. We present the Meikirch model, a conceptual framework for health and disease that views health as a complex adaptive system. We describe this model and analyze some important consequences of its application to healthcare. The resources each person needs to meet the demands of life are both biological and personal, and both function together. While scientific advances in healthcare are hailed, these advances focus mainly on the biologically given potential (BGP) and tend to neglect the personally acquired potential (PAP) of an individual person. Personal growth to improve the PAP strongly contributes to meeting the demands of life. Therefore, in individual and public health care, personal growth deserves as much attention as the BGP. The conceptual framework of the Meikirch model supports a unified understanding of healthcare and serves to develop common goals, thereby rendering interprofessional and intersectoral cooperation more successful. The Meikirch model can be used as an effective tool to stimulate health literacy and improve health-supporting behavior. If individuals and groups of people involved in healthcare interact based on the model, mutual understanding of and adherence to treatments and preventive measures will improve. In healthcare, the Meikirch model also makes it plain that neither pay-for-performance nor value-based payment is an adequate response to improve person-centered healthcare. The Meikirch model is not only a unifying theoretical framework for health and disease but also a scaffold for the practice of medicine and public health. It is fully in line with the theory and practice of evidence-based medicine, person-centered healthcare, and integrative medicine. The model offers opportunities to self-motivate people to improve their health-supporting behavior, thereby making preventive approaches and overall healthcare more effective. We believe that the Meikirch model could induce a paradigm shift in healthcare. The healthcare community is hereby invited to acquaint themselves with this model and to consider its potential ramifications.

Health as a Complex Adaptive System: a new dimension of patient care in internal medicine and general practice

This paper explores the diagnostic and therapeutic potential of a new concept of health. Investigations into the nature of health have led to a new definition that explains health as a complex adaptive system (CAS) and is based on five components (a-e). Humans like all biological creatures must satisfactorily respond to (a) the demands of life. For this purpose they need (b) a biologically given potential (BGP) and (c) a personally acquired potential (PAP). These properties of individuals are embedded within (d) social and (e) environmental determinants of health. Between these five components of health there are 10 complex interactions that justify health to be viewed as a CAS. In each patient, the current state of his health as a CAS evolved from the past, will move forward to a new future, and has to be analyzed and treated as an autonomous whole. A diagnostic procedure is suggested as follows: together with the patient, the five components and 10 complex interactions are assessed. This may help the patient to better understand his situation and to recognize possible next steps that may be useful for him to evolve toward more health by himself. In this process mutual trust in the patient-physician interaction is critical. The described approach offers new possibilities to help patients to improve their health.

Applying a complex adaptive system's understanding of health to primary care

This paper explores the diagnostic and therapeutic potential of a new concept of health. Investigations into the nature of health have led to a new definition that explains health as a complex adaptive system (CAS) and is based on five components (a-e). Humans like all biological creatures must satisfactorily respond to (a) the demands of life. For this purpose they need (b) a biologically given potential (BGP) and (c) a personally acquired potential (PAP). These properties of individuals are embedded within (d) social and (e) environmental determinants of health. Between these five components of health there are 10 complex interactions that justify viewing health as a CAS. In each patient, the current state of health as a CAS evolved from the past, will move forward to a new future, and has to be analyzed and treated as an autonomous whole. A diagnostic procedure is suggested as follows: together with the patient, the five components and 10 complex interactions are assessed. This may help patients to better understand their situations and to recognize possible next steps that may be useful in order to evolve toward better health by themselves. In this process mutual trust in the patient-physician interaction is critical. The described approach offers new possibilities for helping patients improve their health prospects.

Understanding the nature of health: New perspectives for medicine and public health. Improved wellbeing at lower costs

BACKGROUND

Current dilemmas of health care systems call for a new look at the nature of health. This is offered by the Meikirch model. We explore its hypothetical benefit for the future of medicine and public health. Meikirch model: It states: "Health is a dynamic state of wellbeing emergent from conducive interactions between individuals' potentials, life's demands, and social and environmental determinants." "Throughout the life course health results when an individuals' biologically given potential (BGP) and his or her personally acquired potential (PAP), interacting with social and environmental determinants, satisfactorily respond to the demands of life."

METHODS

We explored the Meikirch model's possible applications for personal and public health care.

RESULTS

The PAP of each individual is the most modifiable component of the model. It responds to constructive social interactions and to personal growth. If an individual's PAP is nurtured to develop further, it likely will contribute much more to health than without fostering. It may also compensate for losses of the BGP. An ensuing new culture of health may markedly improve health in the society. The rising costs of health care presumably are due in part to the tragedy of the commons and to moral hazard. Health as a complex adaptive system offers new possibilities for patient care, particularly for general practitioners.

DISCUSSION

Analysis of health systems by the Meikirch model reveals that in many areas more can be done to improve people's health and to reduce health care costs than is done today. The Meikirch model appears promising for individual and public health in low and high income countries. Emphasizing health instead of disease the Meikirch model reinforces article 12 of the International Covenant on Economic, Social and Cultural Rights of the United Nations - that abandons the WHO definition - and thereby may contribute to its reinterpretation.

Towards a dynamic definition of health and disease

A multifactorial and growing crisis of health care systems in the developed world has affected medicine. In order to provide rational responses, some central concepts of the past, such as the definitions of health and disease, need to be updated. For this purpose physicians should initiate a new debate. As a point of departure the following definitions are proposed: Health is a dynamic state of wellbeing characterized by a physical, mental and social potential, which satisfies the demands of a life commensurate with age, culture, and personal responsibility. If the potential is insufficient to satisfy these demands the state is disease. This term includes sickness, illness, ill health, and malady. The described potential is divided into a biologically given and a personally acquired partial potential. Their proportions vary throughout the life cycle. The proposed definitions render it empirically possible to diagnose persons as healthy or diseased and to apportion some of the responsibility for their state of health to individuals themselves. Treatment strategies should always consider three therapeutic routes: improvements of the biologically given and of the personally acquired partial potentials and adaptations of the demands of life. These consequences favourably contrast with those resulting from the WHO-definition of health.

Assessment of the hepatic circulation in humans: new concepts based on evidence derived from a D-sorbitol clearance method

D-Sorbitol (SOR) is safe, is easy to measure, and has an exceptionally high extraction ratio in the normal liver of 0.93+/-0.05 (mean+/-SD). Together with the general interest in hepatic hemodynamics, these facts motivated us to review the usefulness of this compound for the assessment of liver plasma flow in humans. We concluded that in subjects without liver disease the nonrenal clearance of SOR-measured noninvasively-very closely approximates hepatic plasma flow. Because of its lower and more variable extraction ratio, indocyanine green should no longer be used without hepatic vein catheterization. Even in patients with cirrhosis, SOR exhibits higher hepatic extraction ratios than indocyanine green. To fully explore the potential of SOR in the evaluation of such patients attention needs to be paid to the complex changes in architecture and function occurring in this disease. In cirrhotics the noninvasively measured nonrenal clearance of SOR presumably approximates the flow through intact and capillarized sinusoids (functional flow) and reflects the amount of blood having functional contact with hepatocytes. The theoretic background of the method, its accuracy, further research needs, and potentials of various approaches are discussed in detail.

Quantitative liver function tests as surrogate markers for end-points in controlled clinical trials: a retrospective feasibility study

Quantitative liver function tests such as the determination of galactose elimination capacity (GEC) or the aminopyrine breath test (ABT) may have the potential to serve as refined entry criteria and surrogate markers for end-points in controlled clinical trials. The magnitude of a statistically detectable difference in test results and the period of observation required to document such a difference must be known to properly design such trials. Therefore, we explored retrospectively the time course of changes in GEC and ABT and their reproducibility from a cohort of patients with alcoholic cirrhosis followed for 12 to 42 months, with a median of 34 months. In 15 patients who stopped drinking, GEC improved significantly by 0.64 mg/min/kg within 1 year (mean; 95% confidence interval [CI]: 0.42; 0.86). In contrast, it deteriorated by 0.53 mg/min/kg within 1 year (95% CI: 0.32; 0.74) in another 17 patients who continued to drink (P < .01). The residual standard deviation of the changes in GEC with respect to the patients' initial values was 0.43 mg/min/kg (95% CI: 0.32; 0.52). In addition, ABT improved significantly by 0.14% dose x kg/mmol CO2 (95% CI: 0.09; 0.18) in the abstinent group, and deteriorated by 0.09% dose x kg/mmol CO2 (95% CI: 0.06; 0.13) in the nonabstinent group (P < .01). The residual standard deviation in the above sense for ABT was 0.08% dose x kg/mmol CO2 (95% CI: 0.06; 0.10). These data indicate that clinical trials with a sample size of n = 20 in each group must achieve absolute differences (ADs) in GEC of 0.6 mg/min/kg and of 0.7 mg/min/kg to reach statistical significance at the 5% and 1% level, respectively. In the present study, a period of 11 and 12 months was necessary to observe such differences. The corresponding results for the ABT are 0.11% dose x kg/mmol CO2 (9 months of follow-up; 5% level) and 0.13% dose x kg/mmol CO2 (11 months of observation; 1% level), respectively. Provided that patients with liver diseases treated with drugs are similar to the abstinent and nonabstinent patients with alcoholic liver disease investigated in this study, such numbers could serve for the planning of controlled clinical trials, in which the control group is likely to deteriorate and the treated group is expected to improve. Trials based on GEC or ABT would require only 37 or 30 patient years of observation compared with a median of 444 patient years (range, 50-2,100 patient years) reported for various published controlled clinical trials using survival analysis.

Comparison of serine and hippurate as precursor equivalents during infusion of [15N]glycine for measurement of fractional synthetic rates of apolipoprotein B of very-low-density lipoprotein

Enrichment in hippurate has been measured to indicate precursor enrichment during glycine tracer infusion studies to estimate fractional synthetic rates of individual hepatic export proteins. However, hippurate tends to overestimate precursor enrichment. Since glycine is rapidly converted to serine by liver cells, we compared tracer enrichment in hippurate and serine with that of glycine incorporated into apolipoprotein (apo) B-100. Ten healthy control subjects were studied in the postabsorptive state during an 8-hour primed-constant infusion of [15N]glycine (10 mumol.kg-1.h-1). Apo B of very-low-density lipoprotein (VLDL) was isolated by standard ultracentrifugation and isopropanol precipitation. Glycine and serine were isolated from plasma and hydrolyzed apo B, hippurate was isolated from plasma, and [15N]enrichment was determined by gas chromatography-mass spectrometry. Enrichment in serine and glycine isolated from apo B was identical at all time points, and their enrichment in apo B increased asymptotically, approaching an apparent plateau (mean +/- SD: 91% +/- 10% of calculated plateau at 8 hours) that was taken to represent hepatic protein precursor enrichment. Enrichment in both plasma serine and hippurate followed a biphasic pattern and continued to increase until the end of the study, raising the possibility that precursor enrichment had not reached a steady state during the study. The apo B plateau was lower (factor 0.76 +/- 0.27) than the final enrichment in hippurate and higher (factor 1.38 +/- 0.36) than that in plasma serine; however, predictions of protein precursor enrichment based on either metabolite were flawed by a large coefficient of variation (35% v 26%).(ABSTRACT TRUNCATED AT 250 WORDS)

Individualized dosage of gentamicin: a programmed pocket calculator is useful only when applied properly

Various methods of gentamicin dosing were compared in order to evaluate factors that prevent achievement of therapeutic peak and trough plasma concentrations in every patient. When standard doses of 3 x 80 mg of gentamicin/day (i.e., 3 x 170 mumol/day) were administered, only 26% of peak and 51% of trough plasma concentrations were within the desired range. This percentage increased for peak levels to 54% (p less than 0.001) when physicians were instructed in the use of a programmed pocket calculator (PPC) and to 70% (p less than 0.001) when in addition the nursing staff was trained. The best results were achieved when dosing and blood sampling were supervised by a single trained person, 76% of initial peak and 71% of initial trough levels being within the therapeutic range. In this group of patients, further dosage adjustments by the PPC achieved 92% of peak levels in the desired range, while no patient had elevated trough levels. Analysis of the factors that led to these results revealed that neither the laboratory nor the PPC are limiting factors for optimal results. The goal of therapeutic plasma concentrations can be achieved, but requires appropriate attention to the accuracy of blood sampling and dosing. For this purpose, a special program, i.e., more than ordinary attention to drug therapy, is needed.

Urinary caffeine metabolites in man. Age-dependent changes and pattern in various clinical situations

In an exploratory study the 24-h urinary excretion pattern of caffeine and 14 of its major metabolites was studied in 32 volunteers (adults, adolescents and children), 14 patients either with end stage renal disease or liver cirrhosis, 7 heavy smokers and 27 patients on therapy with cimetidine, allopurinol, theophylline or phenytoin. Caffeine and its metabolites were quantified by UV-absorption after liquid/liquid-extraction and HPLC-separation, which ensured proper analysis of 1-methyluric acid. In adults the renal excretion of caffeine derivatives corresponded to an intake of 509 mg caffeine/day, with 1-methyluric acid as the predominant metabolite. About 69% of caffeine was degraded by the paraxanthine pathway, and theobromine- (19%) and the theophylline pathway (14%) were less important. The ratio of paraxanthine formation to urinary caffeine concentration (= clearance equivalent) was about 2.2 ml.min-1.kg-1 in adults, and the corresponding ratios for theophylline and theobromine were 0.43 ml.min-1.kg-1 and 0.59 ml.min-1.kg-1, respectively. As expected, caffeine degradation was impaired in patients with cirrhosis and was increased in persons who smoked heavily or who were on phenytoin therapy. The results document the possibility of noninvasively investigating gross differences in caffeine disposition by analysis of the urinary pattern of its metabolites.

Higher levels of serum aminoterminal type III procollagen peptide, and laminin in alcoholic than in nonalcoholic cirrhosis of equal severity

In vitro models have shown that metabolites of ethanol (acetaldehyde and lactate) stimulate collagen synthesis, thereby, suggesting that they may be important as fibrogenic mediators. The relevance of these findings for fibrogenesis in the human liver in vivo, however, has not as yet been demonstrated. Serum markers for collagen (PIIINP, using radioimmunoassays employing polyclonal antibodies and Fab-fragments (PIIINP-Fab), respectively) and basement membrane (laminin) metabolism were therefore investigated in 25 alcoholic cirrhotics (Pugh-Score: 6.7 +/- 1.9 S.D.) and in 19 comparable nonalcoholic cirrhotics (Pugh-Score: 6.3 +/- 1.5, n.s.) with only slight evidence for inflammation: GOT 28 +/- 22 vs. 24 +/- 21 U/l; GPT 24 +/- 23 vs. 31 +/- 28 U/l; gamma-globulins 24 +/- 8 vs. 22 +/- 5%, respectively (all n.s.). Severity of the disease was assessed by quantitative liver function tests. Levels of PIIINP, PIIINP-Fab and laminin measured by RIA were 21 +/- 19 micrograms/l, 90 +/- 42 micrograms/l and 2.5 +/- 0.8 U/ml in alcoholic cirrhosis and 10 +/- 6 micrograms/l, 61 +/- 10 micrograms/l and 1.9 +/- 0.4 U/ml in nonalcoholic cirrhosis, respectively (all p less than 0.01). Differences on PIIINP and PIIINP-Fab remained significant even after accurate matching for galactose elimination capacity, aminopyrine breath test and hepatic sorbitol clearance. Laminin levels were higher in alcoholic cirrhosis only after matching for the hepatic sorbitol clearance (p less than 0.01). The higher levels of serum markers for collagen and basement membrane metabolism in alcoholic vs. nonalcoholic patients with cirrhosis at equal severity of the disease and with only minimal signs of inflammation may be the clinical reflection of a specific fibrogenic effect of ethanol metabolites.

Effect of pentoxifylline on liver plasma flow in normal man

In ten healthy, male subjects the acute effect of pentoxifylline (a methylxanthine derivative) on liver plasma flow was investigated by the extrarenal sorbitol clearance method and on cardiac output by impedance cardiography. On the placebo day liver plasma flow decreased within 4 h from 769 to 683 ml.min-1 (P less than 0.05) and on the pentoxifylline day (300 mg i.v.) it increased from 764 to 801 ml.min-1 (NS). At the end of the experiment the difference between the groups was also significant (P less than 0.05). There was no significant change in cardiac output, blood pressure or heart rate and individual changes in those values were not correlated with liver plasma flow. There was no correlation either between the plasma concentrations of pentoxifylline or its metabolites and the changes in liver plasma flow. It is concluded that, relative to the spontaneous decrease in liver plasma flow at rest on the placebo day, pentoxifylline increased splanchnic perfusion independent of any change in cardiac output.

The influence of gestational age on bilirubin conjugation in newborns

Unconjugated, mono- and diconjugated bilirubin levels were determined in serum soon after birth, and followed up for several days. Fourteen preterm neonates were studied with a gestational age below 33 weeks (n = 7) or between 34 and 37 weeks (n = 7), respectively, as well as 19 full-term newborns either untreated (n = 9) or treated by phototherapy (n = 10). Bilirubin and its derivatives were analysed by alkaline methanolysis and spectrometry after separation by thin-layer chromatography. In normal full-term neonates total and unconjugated bilirubin reached peak levels at days 2-4. Thereafter, a decline of 11% per day was detectable. Monoconjugates in serum amounted to 3.1 +/- 1.1% of total pigment and remained at that level. The relative amount of diconjugates increased from 0.55 +/- 0.25% (2-4th postnatal day) to 1.62 +/- 0.99% (9-13th day of life). The rapid decline of unconjugated bilirubin paralleled by an increase of diconjugates are an expression of the maturation process for bilirubin conjugation. The premature neonates with less than 33 weeks gestation exhibited an increase of unconjugated serum bilirubin up to the 4-5th postnatal day, the decline thereafter amounted 2% per day. The fraction of 2.3 +/- 1.1% monoconjugates was small and exhibited only a moderate increase in the follow up. In contrast diconjugates were undetectable or very low and remained at this level. These results suggest the presence of a more severe immaturity as well as a slower maturation process of bilirubin conjugation in preterm newborns.(ABSTRACT TRUNCATED AT 250 WORDS)

Ursodeoxycholic acid-induced changes of plasma and urinary bile acids in patients with primary biliary cirrhosis

Ursodeoxycholic acid treatment of patients with primary biliary cirrhosis may lead to relief of pruritus and improvement of biochemical liver tests. The changes in serum and urinary bile acids induced by ursodeoxycholic acid treatment were studied. After 29 patients with primary biliary cirrhosis were treated with ursodeoxycholic acid (750 to 1,000 mg/day) for 6 to 12 mo because of an increase in ursodeoxycholic acid, total plasma bile acids increased from 30.5 +/- 6 mumol/L (mean +/- S.E.M.) to 52.7 +/- 11.7 mumol/L (p less than 0.01). The increase in total plasma bile acids correlated significantly with concentrations of plasma bile acid before treatment (p less than 0.01). The concentrations of endogenous bile acids decreased, mainly because of a decrease of cholic acid. During treatment, glycine conjugation increased and taurine conjugation decreased, whereas sulfation and glucuronidation of bile acids were unchanged. In 10 patients with primary biliary cirrhosis in stages III and IV, urinary excretion of bile acids was also studied. After treatment, ursodeoxycholic acid and its 3-beta isomer and C-1-hydroxylated and C-6-hydroxylated derivatives were also excreted. During treatment, urinary excretion of endogenous bile acids decreased. The increase of ursodeoxycholic acid and the decrease of endogenous bile acids may both be related to the improvement of biochemical liver tests in precirrhotic stages of the disease. In cirrhosis, endogenous bile acids in plasma remained high and changes in liver tests were small.

Paracetamol test: modification by renal function, urine flow and pH

Factors which might affect paracetamol disposition have been studied in a heterogenous group of patients in need of mild analgesia in an intensive care unit. Following oral administration of 1 g of paracetamol, plasma and urinary concentrations of the parent compound and metabolites were assessed by HPLC. The renal clearance of paracetamol was significantly correlated with urine flow (r = 0.84) and creatinine clearance (r = 0.77), but not with urine pH. Metabolite output was diminished in patients with reduced renal function. Despite the heterogeneity of patients and the diversity of drug treatment, the urine to plasma paracetamol concentration ratio appeared remarkably constant in patients with normal renal function (9.8 +/- 2.7). It is concluded that the metabolite to paracetamol ratio may only be regarded as a measure of the drug metabolizing capacity in subjects with normal renal function, if factors influencing urine volume and paracetamol absorption are standardized.

Low fractions of mono- and diconjugated bilirubin in patients with beta-thalassemia: an approach to characterize hepatic conjugation capacity

Unconjugated and mono- and diconjugated bilirubin was determined by alkaline methanolysis and thin-layer chromatography in serum from 16 pediatric patients with homozygous beta-thalassemia (aged 1-23 years), in 14 age-matched controls, and in 26 healthy adults. Total bilirubin amounted to 21 +/- 20 mumol/L in patients with thalassemia compared with 7 +/- 4 mumol/L in healthy children and 11 +/- 3 mumol/L in healthy adults. The fractions of bilirubin conjugates in the various groups were 8 +/- 4% (patients with thalassemia), 18 +/- 5% (age-matched controls; p less than 0.001), and 16 +/- 5% (healthy adults; p less than 0.001). The low fraction of bilirubin conjugates in patients with thalassemia showed no correlation to any other physical or laboratory finding. It is concluded that subnormal values of bilirubin conjugates in thalassemia indicate defective bilirubin conjugation.

Penetration of ciprofloxacin into the cerebrospinal fluid of patients with uninflamed meninges

Nine patients with external ventriculostomy and suffering from hydrocephalus, due to non-inflammatory central nervous system diseases, were given ciprofloxacin (200 mg twice daily iv). Ciprofloxacin concentrations in serum and CSF were measured by HPLC. Single-dose pharmacokinetics were determined in three patients, and 60 and 600 min post-dose levels after repeated administration in six patients. CSF concentrations were maximal 60-120 min after the end of the infusion. The CSF elimination half-life was 260-430 min compared with 145-170 in serum. Post-dose levels at 60 min ranged from 0.042 to 0.223 mg/l (median = 0.110). Repeated administration did not lead to substantial increases in serum and CSF concentrations. With respect to MIC90 values reported for bacteria involved in CNS infections, the CSF concentrations of ciprofloxacin obtained under our experimental conditions would be considered subtherapeutic. Thus ciprofloxacin therapy of CNS infections may be inadequate when only minor impairment of the blood-CSF barrier exists.

Ursodeoxycholic acid in primary biliary cirrhosis: no evidence for toxicity in the stages I to III

In an open, exploratory study, the safety of ursodeoxycholic acid (UDCA) in the treatment of primary biliary cirrhosis (PBC) was investigated. Seven patients in stages I to III and two patients in stage IV were treated for 1 year with 1 g/day of UDCA. Clinical symptoms, and alkaline phosphatase, gamma-glutamyltransferase, alanine aminotransferase (GOT) and aspartate aminotransferase (GTP) levels improved significantly within three months and remained at the lower levels for the period of observation. Results of the galactose elimination capacity (4.7 +/- S.D. 1.4 mg/min per kg) and the aminopyrine breath test (0.60 +/- 0.33% dose/kg per mmol CO2) remained unchanged for 1 year. In all patients total serum bile acids increased and quantitatively UDCA became the most important bile acid. In patients in stages I to III this increase, however, was modest, whereas in patients in stage IV, total serum bile acids reached levels of 140 and 157 mumol/l and UDCA, levels of 90 and 103 mumol/l, respectively. It is concluded that UDCA appears to be safe only in stages I to III and that prognostic stratification based on bile acid levels or on the histological stage of the disease should be an important aspect of controlled clinical trials.

Hepatic and extrahepatic disposition of propofol in patients undergoing coronary bypass surgery

In order to clarify the relative contribution of the liver to the short term disposition of propofol, hepatic blood flow was measured during induction of anaesthesia with an i.v. bolus dose of propofol 2 mg kg-1. Total clearance of the drug was 2390 (SD 340) ml min-1, hepatic extraction 82% and hepatic clearance 1060 (260) ml min-1. During the 60-min period of observation, hepatic extraction of propofol increased from 79% to 92%. It is concluded that, within 1 h, only 44% of the administered dose is removed by the liver. Consequently, drug accumulation may occur with repeated dosing or infusion of propofol. The increase in extraction results presumably from slow release of propofol from the soy-bean emulsion.

Excessive motor impairment two hours after triazolam in the elderly

The pharmacokinetics of triazolam 0.25 mg p.o. and psychomotor coordination were compared in nine healthy, elderly volunteers and nine middle aged controls. Motor coordination, as measured by pursuit rotor performance, was impaired in the elderly even before triazolam administration, and in contrast to the controls it deteriorated to a critical level after the drug. Factors associated with the major decrease in psychomotor performance in the elderly volunteers were poor baseline performance, an additional independent-age factor, and the plasma concentration of free triazolam. Although short acting benzodiazepines may have a less detrimental effect on performance on the morning following their intake, there may be serious motor incoordination and falls may occur if the patients have to rise during the night, particularly when the plasma concentration is high, i.e. about 2 h after dosing.

The teaching and organisation of clinical pharmacology in European medical schools (W.H.O. Working Group on Clinical Pharmacology)

A World Health Organisation (European Regional Office) working party has been established to review the progress of clinical pharmacology in European countries. As part of this review a questionnaire on the teaching of clinical pharmacology was sent to the Deans of all 350 medical schools in the region. Very few replies were received from U.S.S.R., Greece and Portugal and these countries' returns were not analysed further. The overall compliance rate (excluding these countries) was 82% with a figure of 84% from Western Europe and 74% from Eastern Europe. An average time of 96 h (range 0-320) was devoted to pharmacology teaching in the medical curriculum in Western Europe with 124 (0-240) h in Eastern Europe. In contrast 28 h (0-210) was devoted to clinical pharmacology teaching in Western Europe and 27 h (0-90) in Eastern Europe. On average in Western Europe each medical school had 2 individuals trained in clinical pharmacology with 1.3 posts in the subject and the figures for Eastern Europe were 2.3 and 1.1 respectively. However these figures hide a wide variance in the teaching of clinical pharmacology. Particularly in Western Europe there are a number of medical schools in Italy, Spain and the Federal Republic of Germany (FRG) where clinical pharmacology is not taught and there is a dearth of individuals trained in the subject. Every effort to encourage clinical pharmacology and its teaching should be made, particularly in these countries.

Lack of interference by sorbitol with aminopyrine breath test

The effect of sorbitol on the aminopyrine breath test was investigated in 13 patients with various liver diseases given a bolus dose of sorbitol 20 mg.kg-1 i.v. 30 min after 14C-aminopyrine and 13 patients without the sorbitol bolus who also underwent an aminopyrine breath test. The time course of 14CO2 exhalation after the bolus of sorbitol did not differ from that in the control group.

Association of primary biliary cirrhosis and blue rubber bleb naevus syndrome

A 66-year old woman presented all the features of primary biliary cirrhosis and the blue rubber bleb naevus syndrome. This case represents a new association of primary biliary cirrhosis with an inherited disease.

Superiority of the Child-Pugh classification to quantitative liver function tests for assessing prognosis of liver cirrhosis

To evaluate the prognostic value of quantitative liver function tests in comparison with established prognostic variables, the data of 47 patients with liver cirrhosis were analysed. A total of 16 variables, comprising the galactose elimination capacity and the indocyanine green clearance, the Child-Pugh classification, and several clinical and biochemical variables were subjected to Kaplan-Meier life-table analysis and Cox proportional hazards regression analysis. As independent variables, poor prognosis was associated significantly with increasing Child-Pugh score (p less than 0.00001), whereas the galactose elimination capacity (p = 0.03) and the indocyanine green clearance (p less than 0.001) were less sensitive indicators. The regression analysis showed prognostic value in decreasing sequence for Child-Pugh classification, age, sex, history of upper GI haemorrhage, and alkaline phosphatase activity. The quantitative liver function tests evaluated in the present work have less prognostic value than routinely accessible variables.

Dose equivalence of midazolam and triazolam. A psychometric study based on flicker sensitivity, reaction time and digit symbol substitution test

The pharmacodynamic potency of oral midazolam, a new ultrashort-acting hypnotic benzodiazepine, has been evaluated relative to a standard dose of triazolam, a well established oral benzodiazepine with a similar pharmacological profile. In a balanced design, double-blind cross-over study 6 healthy volunteers received 3.75, 7.5, and 15 mg midazolam and 0.25 mg triazolam orally, at 8 a.m., at weekly intervals. Drug effects were repeatedly measured over 8 h by a new psychometric method, the threshold amplitude for perception of flickering light (TPF) assessed at 5 and 30 Hz. Auditory reaction time, digit-symbol substitution test (DSST), and self-rating by subjects served as reference standards. Median midazolam doses equivalent to 0.25 mg triazolam, interpolated on dose-response curves for peak effects, were 5.2 mg (TPF 30 Hz), 6.4 mg (TPF 5 Hz), 6.5 mg (DSST), and 7.4 mg (reaction time), respectively. Alternative methods of data analysis gave similar results. Introduction of TPF as a highly reproducible and sensitive measure of the effect of benzodiazepines on the CNS offers new opportunities to compare the relative potencies of different benzodiazepines in man. Since clinical experience has shown 0.25 mg triazolam to be safe and effective, it is concluded that the corresponding single oral dose of midazolam is between 5 and 8 mg.

Steady-state extrarenal sorbitol clearance as a measure of hepatic plasma flow

Hepatic plasma flow was assessed with sorbitol (hepatic extraction = 0.96) at steady state. After infusion of 50 mg/min for 3 h, total and renal sorbitol clearances were calculated, and the extrarenal clearance was obtained by taking the difference between the two. In normal volunteers, the mean (+/- SD) extrarenal sorbitol clearance was 10.6 +/- 2.1 ml/min.kg. In patients with various liver diseases, it was correlated more closely to the fractional clearance of indocyanine green (r = 0.83, n = 57) than the galactose elimination capacity (r = 0.66, n = 55). Hepatic vein catheterization showed that the hepatic extraction of sorbitol was always much higher than the extraction of indocyanine green; there was no evidence for extrahepatic, extrarenal sorbitol elimination. On the basis of these findings, sorbitol is kinetically superior to indocyanine green and, although the noninvasively determined extrarenal sorbitol clearance at steady state may not be equal to total hepatic plasma flow, it may at least be regarded as a measure of parenchymal liver plasma flow.

Increased systemic availability of albendazole when taken with a fatty meal

We have studied the systemic availability of oral albendazole in 6 patients with echinococcosis either fasting or with breakfast. Albendazole sulphoxide, the pharmacologically active principle, was assayed by HPLC. Mean plasma concentrations and AUCs were 4.5 times higher when albendazole was given with breakfast than when administered in the fasting state. We conclude that therapy of echinococcosis with albendazole requires the drug to be taken with meals and that administration on an empty stomach might be more appropriate when intraluminal effects are desired, e.g. for intestinal parasites.

Inadequate reporting of analytical quality control in the clinical pharmacological literature

Quality control parameters were surveyed in the clinical pharmacological literature of 1984 and 1985, as published by the European Journal of Clinical Pharmacology, the British Journal of Clinical Pharmacology, and Clinical Pharmacology and Therapeutics. Papers which included newly developed methods gave details about precision and sensitivity in more than 60% and about accuracy and specificity in nearly 30%. Fewer than one-third of all articles containing analytical methods, described by citation only, gave information about precision and sensitivity in the originating laboratory, and accuracy and specificity were reported by less than 10% of them. These data represent an important deficiency in laboratory information in the clinical pharmacological literature.

The 30-minute aminopyrine breath test: optimization of sampling times after intravenous administration of 14C-aminopyrine

In a retrospective analysis of 78 well-defined patients, the procedure of the aminopyrine breath test was evaluated. After intravenous administration of 14C-aminopyrine (1.5 microCi, 1 mg) 14CO2 was sampled at 15-min intervals for 1 h. Samples taken at 15, 30, 45 and 60 min were similarly able to distinguish between patients with mild liver disease and patients with enzyme induction. The results of the aminopyrine breath test at each sampling time were highly correlated with the galactose elimination capacity and the fractional clearance of indocyanine green. It is concluded that sampling at 30 min represents a satisfactory compromise between practicality and accuracy of the test.

Non-invasive evaluation of portal-systemic shunting in man by D-sorbitol bioavailability

Portal-systemic shunting is an important circulatory abnormality in patients with cirrhosis. This study explores the potential of the natural polyol D-sorbitol as test compound for non-invasive assessment of shunting. Ten normal subjects, 10 patients with cirrhosis and 12 cirrhotics with surgical portacaval shunts were studied after oral and intravenous administration of a 2 g dose of sorbitol. As measured by the H2 breath test, removal from the intestinal lumen was complete in both groups. Bioavailability of sorbitol, calculated as ratio of the areas under the plasma concentration/time curve after p.o. and i.v. administration, was zero in normal subjects, 0.29 +/- 0.15 in cirrhotic patients, and 0.38 +/- 0.11 in patients with portacaval shunts. Calculation of bioavailability on the basis of urinary outputs of sorbitol gave similar results. It is concluded that the bioavailability of sorbitol reflects portal-systemic shunting, although the relatively low figures suggest some degree of sorbitol metabolism by enterocytes.

Bioavailability determination of lidocaine by capillary gas chromatography ammonia chemical ionization mass spectrometry

A method was developed to measure bioavailability of lidocaine by simultaneous peroral and intravenous dosing. Lidocaine hydrochloride corresponding to 125 mg base was given perorally. Simultaneously, 30 mg of deuterated lidocaine-d3 were injected intravenously. Blood samples were taken at intervals for 270 min. Plasma samples were spiked with mepivacaine hydrochloride as internal standard, alkalinized to pH 11.7 and extracted with diethyl ether. The extracts were analysed by capillary GC ammonia CI MS using a 15 m X 0.32 mm i.d. glass capillary column coated with SE-54. The ion source pressure was 0.4 Torr of ammonia as reagent gas. Quasimolecular ions were monitored at m/z 235, 238 and 247 for lidocaine, lidocaine-d3 and mepivacaine, respectively. Calibration curves were linear from 0.2 to 5.0 nmol lidocaine ml-1 plasma. Interday reproducibility of this method was 6.9% for lidocaine-d3 (n = 16; 1.90 +/- 0.13 nmol ml-1). Bioavailability of lidocaine in 5 normal volunteers ranged from 26 to 36% (mean 31 +/- SD 5%) and in a cirrhotic with an end-to-side portacaval shunt it approached 100%, as anticipated. The method is well suited for determination of bioavailability of lidocaine after simultaneous administration of rather small and safe doses both intravenously and perorally.

Mechanism of the excessive sedative response of cirrhotics to benzodiazepines: model experiments with triazolam

Mechanisms responsible for disproportional sedation resulting from triazolam administration to patients with cirrhosis were investigated. Ordinary sedative doses (0.25 mg) were given p.o. to 8 cirrhotics and 18 controls. Plasma concentrations of unbound drug were assessed by capillary gas chromatography and equilibrium dialysis. Median apparent oral clearances of unbound triazolam were 14.8 ml per min per kg in cirrhotics and 23.9 ml per min per kg in controls (p less than 0.01). Clearances were significantly correlated with severity of liver disease as assessed by the aminopyrine breath test (Rs = 0.77, n = 17, p less than 0.001). At a time when plasma concentrations of unbound triazolam were the same in both groups, i.e., 2.25 hr after dosing, flicker sensitivity at 5 Hz which was used as an index of CNS performance was impaired by a factor of 3.2 in cirrhotics and 1.4 in controls (p less than 0.01 for group difference). Performance was also significantly lower in cirrhotics with the digit symbol substitution test (p less than 0.05). It is concluded that, in patients with cirrhosis, disproportional sedation after benzodiazepine administration may be due not only to impaired drug elimination, but also to hypersensitivity of the brain.