Data Systems in Mental Health

The proper utilization of data information systems in mental health care can noticeably improve the quality and efficacy of such care. The World Health Organization is in a key position to encourage and assist governments in achieving the fullest possible application of knowledge in the development and utilization of such systems to the benefit of the greatest numbers of the world’s population.

This paper briefly delineates some of the common information needs of the providers of mental health care, discusses the feasibility of automated data systems, and describes some already existing psychiatric information systems. Finally, it proposes ways and means by which the WHO can more efficiently aid its member nations by coordinating efforts in establishing mental health information systems. Recommendations include establishment of an information clearinghouse on data systems, a group coordinating dissemination of this information, a common pool of specialists in the area, and development of regional computing facilities under the auspices of the WHO.

Contributions to the theory of optimal resource allocation

A problem in optimal resource allocation is considered for n jobs with identically distributed service times admitting a monotone hazard function. If the hazard function is increasing, it is shown that the procedure of allocating the full resource individually to each job until its completion minimizes the expected completion time of the jth job. The procedure which at any instant of time equally allocated the resource among all of the remaining jobs is shown to minimize the expected total cumulative waiting time if the hazard is decreasing.

Pharmacometabolomic Assessments of Atenolol and Hydrochlorothiazide Treatment Reveal Novel Drug Response Phenotypes

Achieving hypertension (HTN) control and mitigating the adverse health effects associated with HTN continues to be a global challenge. Some individuals respond poorly to current HTN therapies, and mechanisms for response variation remain poorly understood. We used a nontargeted metabolomics approach (gas chromatography time-of-flight/mass spectrometry gas chromatography time-of-flight/mass spectrometry) measuring 489 metabolites to characterize metabolite signatures associated with treatment response to anti-HTN drugs, atenolol (ATEN), and hydrochlorothiazide (HCTZ), in white and black participants with uncomplicated HTN enrolled in the Pharmacogenomic Evaluation of Antihypertensive Responses study. Metabolite profiles were significantly different between races, and metabolite responses associated with home diastolic blood pressure (HDBP) response were identified. Metabolite pathway analyses identified gluconeogenesis, plasmalogen synthesis, and tryptophan metabolism increases in white participants treated with HCTZ (P < 0.05). Furthermore, we developed predictive models from metabolite signatures of HDBP treatment response (P < 1 × 10(-5)). As part of a quantitative systems pharmacology approach, the metabolites identified herein may serve as biomarkers for improving treatment decisions and elucidating mechanisms driving HTN treatment responses.

Update on procalcitonin measurements

Procalcitonin (PCT) is used as a biomarker for the diagnosis of sepsis, severe sepsis and septic shock. At the same time, PCT has also been used to guide antibiotic therapy. This review outlines the main indications for PCT measurement and points out possible pitfalls. The classic indications for PCT measurement are: (i) confirmation or exclusion of diagnosis of sepsis, severe sepsis, or septic shock, (ii) severity assessment and follow up of systemic inflammation mainly induced by microbial infection, and (iii) individual, patient adapted guide of antibiotic therapy and focus treatment. Using serially monitored PCT levels, the duration and need of antibiotic therapy can be better adapted to the individual requirements of the patient. This individualized approach has been evaluated in various studies, and it is recommended to be a part of an antibiotic stewardship program.

Evaluation of mid-regional pro-atrial natriuretic peptide, procalcitonin, and mid-regional pro-adrenomedullin for the diagnosis and risk stratification of dyspneic ED patients

OBJECTIVE

The aim of this study was to evaluate the diagnostic and the prognostic value of a laboratory panel consisting of mid-regional pro-atrial natriuretic peptide (MR-proANP), procalcitonin (PCT), and mid-regional pro-adrenomedullin (MR-proADM) for patients presenting to the emergency department (ED) with acute dyspnea.

METHODS

We prospectively enrolled ED patients who presented with a chief complaint of dyspnea and who had an uncertain diagnosis after physician evaluation. Final primary diagnosis of the cause of shortness of breath was confirmed through additional testing per physician discretion. We recorded inpatient admission and 30-day mortality rates.

RESULTS

One hundred fifty-four patients were enrolled in the study. Congestive heart failure exacerbation was the final primary diagnosis in 42.2% of patients, while infectious etiology was diagnosed in 33.1% of patients. For the diagnosis of congestive heart failure exacerbation, MR-proANP had a sensitivity of 92.7% and specificity of 36.8%, with a negative likelihood ratio (LR-) of 0.16 and a positive likelihood ratio (LR+) of 1.44 (cut-off value: 120 pmol/L). For the diagnosis of an infectious etiology, PCT had a 96.5% specificity and 48.8% sensitivity (LR-: 0.58, LR+: 13.8, cutoff value: 0.25 ng/mL). As a prognostic indicator, MR-proADM demonstrated similar values: odds ratio for 30-day mortality was 8.5 (95% CI, 2.5-28.5, cutoff value: 1.5 nmol/L) and the area under the receiver operating characteristic curve in predicting mortality was 0.81 (95% CI, 0.71-0.91).

CONCLUSION

The good negative LR- of MR-proANP and the good positive LR+ of PCT may suggest a role for these markers in the early diagnosis of ED patients with dyspnea. Furthermore, MR-proADM may assist in risk stratification and prognosis in these patients..

Biomarkers in the critically ill patient: procalcitonin

Infection and/or sepsis biomarkers should help to make the diagnosis and thus initiate therapy earlier, help to differentiate between infectious and sterile inflammation, allow the use of more-specific antimicrobials, shorten the time of antimicrobial use, and ideally identify distinct phenotypes that may benefit from specific adjunctive sepsis therapies. Procalcitonin (PCT) was proposed as a sepsis and infection marker more than 15 years ago. Meanwhile, PCT has been evaluated in various clinical settings. In this review the present use of PCT on the ICU and in critically ill patients is summarized, included it's role for diagnosis of severe sepsis and septic shock and antibiotic stewardship with PCT.

Biomarkers in the critically ill patient: procalcitonin

Infection and/or sepsis biomarkers should help to make the diagnosis and thus initiate therapy earlier, help to differentiate between infectious and sterile inflammation, allow the use of more-specific antimicrobials, shorten the time of antimicrobial use, and ideally identify distinct phenotypes that may benefit from specific adjunctive sepsis therapies. Procalcitonin (PCT) was proposed as a sepsis and infection marker more than 15 years ago. Meanwhile, PCT has been evaluated in various clinical settings. In this review the present use of PCT on the ICU and in critically ill patients is summarized, included it's role for diagnosis of severe sepsis and septic shock and antibiotic stewardship with PCT.

Early changes of procalcitonin may advise about prognosis and appropriateness of antimicrobial therapy in sepsis

PURPOSE

The objective of this study is to define if early changes of procalcitonin (PCT) may inform about prognosis and appropriateness of administered therapy in sepsis.

METHODS

A prospective multicenter observational study was conducted in 289 patients. Blood samples were drawn on day 1, that is, within less than 24 hours from advent of signs of sepsis, and on days 3, 7, and 10. Procalcitonin was estimated in serum by the ultrasensitive Kryptor assay (BRAHMS GmbH, Hennigsdorf, Germany). Patients were divided into the following 2 groups according to the type of change of PCT: group 1, where PCT on day 3 was decreased by more than 30% or was below 0.25 ng/mL, and group 2, where PCT on day 3 was either increased above 0.25 ng/mL or decreased less than 30%.

RESULTS

Death occurred in 12.3% of patients of group 1 and in 29.9% of those of group 2 (P < .0001). Odds ratio for death of patients of group 1 was 0.328. Odds ratio for the administration of inappropriate antimicrobials of patients of group 2 was 2.519 (P = .003).

CONCLUSIONS

Changes of serum PCT within the first 48 hours reflect the benefit or not of the administered antimicrobial therapy. Serial PCT measurements should be used in clinical practice to guide administration of appropriate antimicrobials.

The natural elimination rate of procalcitonin in patients with normal and impaired renal function

OBJECTIVE

Procalcitonin (PCT) plasma concentrations and its kinetic can be used as a diagnostic tool in critically ill patients and patients with sepsis. Since renal dysfunction is a frequent complication in these patients, and PCT is a protein with a low molecular weight, we have measured the half-life time of PCT after peak concentrations in patients with normal and impaired renal function. We also have analyzed the influence of patients age and gender on PCT elimination kinetics.

DESIGN

Prospective clinical study. Renal dysfunction was assessed by plasma creatinine. The half-life time of PCT was evaluated 24 and 48 h after acute induction of PCT, when the focus of PCT induction has rapidly been eliminated.

SETTING

Intensive care unit of our University hospital, a tertiary health care institution.

PATIENTS

69 patients were included into the study.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

The half-life-time of PCT was not significantly altered during renal dysfunction (26.1-33.1 h, 25-50 percentiles, creatinine clearance < 30 ml/min) when compared with normal renal function (22.3-28.9 h). It neither correlated with creatinine clearance (p=0.14), nor age (p=0.99) or gender (p=0.90, Pearson product-moment correlation).

CONCLUSIONS

The data of the present study demonstrate that assessment of PCT kinetic can also be used for diagnostic and prognostic reasons in patients with renal dysfunction. It may, however, exceed 24 h also in patients with normal renal function. As to the present knowledge, renal secretion does not contribute as a main pathway to PCT elimination.

Copeptin, a novel prognostic biomarker in ventilator-associated pneumonia

Background

The present study sought to investigate the correlation of copeptin with the severity of septic status in patients with ventilator-associated pneumonia (VAP), and to analyze the usefulness of copeptin as a predictor of mortality in VAP.

Methods

The prospective observational cohort study was conducted in a teaching hospital. The subjects were 71 patients consecutively admitted to the intensive care unit from October 2003 to August 2005 who developed VAP. Copeptin levels were determined on day 0 and day 4 of VAP. Patients were followed for 28 days after the diagnosis, when they were considered survivors. Patients who died before day 28 were classified as nonsurvivors. There were no interventions.

Results

Copeptin levels increased from sepsis to severe sepsis and septic shock both on day 0 and day 4 (P = 0.001 and P = 0.009, respectively). Variables included in the univariable logistic regression analysis for mortality were age, gender, Acute Physiology and Chronic Health Evaluation II score and ln copeptin on day 0 and day 4. Mortality was directly related to ln copeptin levels on day 0 and day 4, with odds ratios of 2.32 (95% confidence interval, 1.25 to 4.29) and 2.31 (95% confidence interval, 1.25 to 4.25), respectively. In a multivariable logistic regression model for mortality, only ln copeptin on day 0 with odds ratio 1.97 (95% confidence interval, 1.06 to 3.69) and ln copeptin on day 4 with odds ratio 2.39 (95% confidence interval, 1.24 to 4.62) remained significant.

Conclusion

Our data demonstrate that copeptin levels increase progressively with the severity of sepsis and are independent predictors of mortality in VAP.

Decreases in procalcitonin and C-reactive protein are strong predictors of survival in ventilator-associated pneumonia

Introduction

This study sought to assess the prognostic value of the kinetics of procalcitonin (PCT), C-reactive protein (CRP) and clinical scores (clinical pulmonary infection score (CPIS), Sequential Organ Failure Assessment (SOFA)) in the outcome of ventilator-associated pneumonia (VAP) at an early time point, when adequacy of antimicrobial treatment is evaluated.

Methods

This prospective observational cohort study was conducted in a teaching hospital. The subjects were 75 patients consecutively admitted to the intensive care unit from October 2003 to August 2005 who developed VAP. Patients were followed for 28 days after the diagnosis, when they were considered survivors. Patients who died before the 28th day were non-survivors. There were no interventions.

Results

PCT, CRP and SOFA score were determined on day 0 and day 4. Variables included in the univariable logistic regression model for survival were age, Acute Physiology and Chronic Health Evaluation (APACHE) II score, decreasing ΔSOFA, decreasing ΔPCT and decreasing ΔCRP. Survival was directly related to decreasing ΔPCT with odds ratio (OR) = 5.67 (95% confidence interval 1.78 to 18.03), decreasing ΔCRP with OR = 3.78 (1.24 to 11.50), decreasing ΔSOFA with OR = 3.08 (1.02 to 9.26) and APACHE II score with OR = 0.92 (0.86 to 0.99). In a multivariable logistic regression model for survival, only decreasing ΔPCT with OR = 4.43 (1.08 to 18.18) and decreasing ΔCRP with OR = 7.40 (1.58 to 34.73) remained significant. Decreasing ΔCPIS was not related to survival (p = 0.59). There was a trend to correlate adequacy to survival. Fifty percent of the 20 patients treated with inadequate antibiotics and 65.5% of the 55 patients on adequate antibiotics survived (p = 0.29).

Conclusion

Measurement of PCT and CRP at onset and on the fourth day of treatment can predict survival of VAP patients. A decrease in either one of these marker values predicts survival.

Correlation of procalcitonin and C-reactive protein to inflammation, complications, and outcome during the intensive care unit course of multiple-trauma patients

Background

A comparison of the amount of and the kinetics of induction of procalcitonin (PCT) with that of C-reactive protein (CRP) during various types of and severities of multiple trauma, and their relation to trauma-related complications, was performed.

Methods

Ninety adult trauma patients admitted to the intensive care unit of our tertiary care hospital were evaluated in a prospective case study. During the initial 24 hours after trauma the Injury Severity Score, the Sepsis-related Organ Failure Assessment score, and the Acute Physiology and Chronic Health Evaluation II score were evaluated. PCT, CRP, the sepsis criteria (American College of Chest Physicians/Society of Critical Care Medicine definitions), and the Sepsis-related Organ Failure Assessment score were measured at days 1–7, as well as at days 14 and 21, concluding the observation period with the 28-day survival.

Results

The induction of PCT and CRP varied in patients suffering from trauma. PCT increased only moderately in most patients and peaked at day 1–2 after trauma, the concentrations rapidly declining thereafter. CRP ubiquitously increased and its kinetics were much slower. Complications such as sepsis, infection, blood transfusion, prolonged intensive care unit treatment, and poor outcome were more frequent in patients with initially high PCT (>1 ng/ml), whereas increases of CRP showed no positive correlation.

Conclusion

In patients with multiple trauma due to an accident, the PCT level provides more information than the CRP level since only moderate amounts of PCT are induced, and higher concentrations correlate with more severe trauma and a higher frequency of various complications, including sepsis and infection. Most importantly, the moderate trauma-related increase of PCT and the rapidly declining concentrations provide a baseline value near to the normal range at an earlier time frame than for CRP, thus allowing a faster and more valid prediction of sepsis during the early period after trauma.

Markers for sepsis diagnosis: what is useful?

Timely diagnosis of the different severities of septic inflammation is potentially lifesaving because therapies that have been shown to lower mortality should be initiated early. Sepsis and severe sepsis are accompanied by clinical and laboratory signs of systemic inflammation but patients with inflammation caused by noninfectious causes may present with similar signs and symptoms. It is important to identify markers for an early diagnosis of sepsis and organ dysfunction. This article presents currently interesting sepsis biomarkers. Other novel markers and their potential role are discussed.

Biomarkers of sepsis: clinically useful?

PURPOSE OF REVIEW

The purpose of this review is to indicate recent developments in biomarkers of sepsis and to evaluate their impact on clinical use. According to the 'surviving sepsis campaign,' diagnosis of sepsis and infection is urgent; early and specific treatment is most effective to reduce complications and to decrease mortality.

RECENT FINDINGS

A variety of biomarkers of sepsis is presently available. The diagnostic spectrum of the various markers, however, is different. Some primarily indicate severity of inflammation (e.g. interleukin-6), others respond to infection, but do not indicate the host response well (endotoxin, lipoprotein binding protein, triggering receptor on myeloid cells). There are new markers with limited clinical experience, for example triggering receptor on myeloid cells or mid-pro atrial natriuretic peptide (Seristra, Brahms AG, Hennigsdorf, Germany). Procalcitonin is a well-established biomarker of sepsis that fulfills several criteria of clinical needs: it responds both to infection and severity of inflammation and thus has an impact on therapy. Recent studies indicate that antibiotic treatment can also be guided by procalcitonin. Further indications, including diagnosis of invasive bacterial infections and diagnosis of sepsis in neonates and children have been reported recently.

SUMMARY

Recent data and cumulative analyses indicate that biomarkers of sepsis improve diagnosis of sepsis. However, only a few markers have impact on therapy and fulfill the clinical requirements. Procalcitonin is a well-established marker, indicating infection, sepsis, and progression to the more severe stages of the disease. Today, this biomarker should be in the diagnostic portfolio of an intensive care unit or emergency ward.

Der Patient mit Ornithintranscarbamylasemangel

Ornithine transcarbamylase deficiency (OTCD) is the most common inborn urea cycle disorder. Patients with OTCD are at risk of acute metabolic decompensation with hyperammonemia and subsequent encephalopathy, coma and death. Symptoms may be triggered by infections, drugs and stress, evoked by trauma, pain, fear, surgery and anaesthesia or by episodes of protein catabolism, i.e. fasting-induced, post partum or during gastrointestinal bleeding. Several specific considerations must be made for anaesthetic and intensive care management in patients with this disease in order to avoid metabolic decompensation. We report the intensive care management of the first manifestation of late-onset OTCD in a 16-year-old girl and a course of inconspicuous general anaesthesia with midazolam, s-ketamine, fentanyl and isoflurane in a 22-year-old girl with known OTCD.

Mannan-binding lectin and procalcitonin measurement for prediction of postoperative infection

Introduction

Postoperative infection is a major cause of morbidity and mortality. We investigated two serum markers for their ability to identify patients at risk for postoperative infection. Mannan-binding lectin (MBL) is a central molecule of the innate immune system and MBL deficiency is known to predispose to infection. Procalcitonin (PCT) is a sensitive marker for bacterial infection.

Methods

We investigated 162 patients undergoing elective surgery for cancer of the gastrointestinal tract. Patients were classified as having no complications (group A), having infection for unknown reason (group B) or having sepsis after events like aspiration or anastomotic leakage (group C). Analysis was done pre- and postoperatively for serum levels of MBL, PCT and C-reactive-protein. DNA was preoperatively sampled and stored and later analysed for genetic polymorphisms of MBL.

Results

The preoperative serum levels of MBL were significantly lower in group B patients than in group A patients (1332 ± 466 ng/ml versus 2523 ± 181 ng/ml). PCT measured on day one post-surgery was significantly higher in group B patients than in group A (3.33 ± 1.08 ng/ml versus 1.38 ± 0.17 ng/ml). Patients with an aberrant MBL genotype had a significantly higher risk of postoperative infections than wild-type carriers (p < 0.05).

Conclusion

Preoperative MBL and early postoperative PCT measurement may help identify patients at risk for postoperative infection.

[Procalcitonin as a marker for severe sepsis in an immunosuppressed patient]

A 22 year old female was admitted to the emergency department with high fever up to 41,5 degrees C, tachycardia, and arterial hypotension. Clinically, she presented with bilateral pulmonary coarse crackles. Diagnosis on admission was pneumonia with septic shock. Intriguingly, procalcitonin (PCT) was increased early, reaching up to 435 ng/mL, while C-reactive protein levels were only moderately increased, with several days delay. The sepsis was originated from a multi-resistant pseudomonas aeruginosa pneumonia. Remarkably, the course of PCT levels reflected the severity of septic shock in that it paralleled noradrenaline demand. Ten months previously, the patient had been diagnosed with acute disseminated brainstem encephalitis (ADEM), and had received two cycles of intravenous cyclophosphamide. Our case illustrates that PCT is an early marker for sepsis and it indicates that PCT may also be a valuable marker for the severity of sepsis in immunosuppressed patients.

Procalcitonin and C-reactive protein during systemic inflammatory response syndrome, sepsis and organ dysfunction

Introduction

Both C-reactive protein (CRP) and procalcitonin (PCT) are accepted sepsis markers. However, there is still some debate concerning the correlation between their serum concentrations and sepsis severity. We hypothesised that PCT and CRP concentrations are different in patients with infection or with no infection at a similar severity of organ dysfunction or of systemic inflammatory response.

Patients and methods

One hundred and fifty adult intensive care unit patients were observed consecutively over a period of 10 days. PCT, CRP and infection parameters were compared among the following groups: no systemic inflammatory response syndrome (SIRS) (n = 15), SIRS (n = 15), sepsis/SS (n = 71) (including sepsis, severe sepsis and septic shock [n = 34, n = 22 and n = 15]), and trauma patients (n = 49, no infection).

Results

PCT and CRP concentrations were higher in patients in whom infection was diagnosed at comparable levels of organ dysfunction (infected patients, regression of median [ng/ml] PCT = -0.848 + 1.526 sequential organ failure assessment [SOFA] score, median [mg/l] CRP = 105.58 + 0.72 SOFA score; non-infected patients, PCT = 0.27 + 0.02 SOFA score, P < 0.0001; CRP = 84.53 - 0.19 SOFA score, P < 0.005), although correlation with the SOFA score was weak (R = 0.254, P < 0.001 for PCT, and R = 0.292, P < 0.001 for CRP). CRP levels were near their maximum already during lower SOFA scores, whereas maximum PCT concentrations were found at higher score levels (SOFA score > 12).

PCT and CRP concentrations were 1.58 ng/ml and 150 mg/l in patients with sepsis, 0.38 ng/ml and 51 mg/l in the SIRS patients (P < 0.05, Mann–Whitney U-test), and 0.14 ng/ml and 72 mg/l in the patients with no SIRS (P < 0.05). The kinetics of both parameters were also different, and PCT concentrations reacted more quickly than CRP.

Conclusions

PCT and CRP levels are related to the severity of organ dysfunction, but concentrations are still higher during infection. Different sensitivities and kinetics indicate a different clinical use for both parameters.

Induction of procalcitonin and proinflammatory cytokines in an anhepatic baboon endotoxin shock model

Our objective was to evaluate the role of the liver for procalcitonin (PCT) and cytokine induction in a baboon endotoxin shock model. Complete liver resection with portocaval anastomosis was established in a baboon prior to the induction of endotoxin shock by intravenous administration of endotoxin (100 microg/kg LPS Escherichia coli). Two baboons without surgical intervention were used as controls. Plasma concentrations of PCT, tumor necrosis factor (TNF)-alpha, interleukin (IL) 6, IL-8, endotoxin, and hemodynamic and metabolic parameters were measured pre- and postoperatively and until 6 h after endotoxin administration. PCT concentrations increased to 1.2 and 4.6 ng/mL in control animals at 6 h, but remained below 0.3 ng/mL in the anhepatic baboon. IL-6 and IL-8 increased only for few hours in controls, but remained elevated in the hepatectomized animal near their maximum (IL-6, 2-6 ng/mL) or several-fold higher (IL-8, 30-35 ng/mL), whereas TNF-alpha response was only a small fraction (0.3 ng/mL) of the controls. Endotoxin was much higher and longer persisting in the hepatectomized animal compared with controls. The near absence of PCT production in the anhepatic baboon suggests a primary role for the liver as a source of PCT production during endotoxin shock. Furthermore, the liver also seems to be an important source of TNF-alpha, but not IL-6 or IL-8.

Pathobiochemistry and clinical use of procalcitonin

Induction of the protein procalcitonin during infection and inflammation was first described approximately 10 years ago. A large number of publications, primarily clinical studies, demonstrate the increasing use of procalcitonin in modern clinical practice. However, data on the biological function and origin of procalcitonin is scarce. Findings regarding the possible role and source of procalcitonin in sepsis and infection were recently published, and the pathophysiology of the protein has meanwhile been investigated in various experimental models. Procalcitonin obviously has certain biological functions, and it is also known to be specifically induced. Given the hormonal origin of the mature protein and the inflammation-related functions of its propeptides, some investigators suggest that procalcitonin should be referred to as a "hormokine," although its biological functions should be studied in more detail. This review will survey the data now available in recent publications on the induction, production sources, possible biological functions and clinical uses of procalcitonin.

Early increase of procalcitonin after cardiovascular surgery in patients with postoperative complications

OBJECTIVE

Type and frequency of postoperative abnormalities were registered after cardiovascular surgery to evaluate the aetiology and diagnostic value of increased concentrations of procalcitonin (PCT) and C-reactive protein (CRP) during the early postoperative period.

DESIGN

Prospective, observational study.

PATIENTS

Two hundred and eight patients undergoing coronary artery bypass grafting or valve replacement requiring cardiopulmonary bypass were monitored for 7 days postoperatively for various types of infectious or non-infectious complications. Plasma PCT and CRP levels were measured on day 1 and day 2 after surgery and, when increased, until day 7.

RESULTS

More patients with PCT above 2 ng/ml on day 1 or 2 (n=55) had postoperative abnormalities (95%) than patients with lower PCT (59%). Specifically, the incidence of three or more criteria of the "systemic inflammatory response syndrome" was 45% versus 4% (area under the curve of the receiver operating characteristic 0.866); positive inotropic support was needed in 65% versus 9% (0.870); respiratory insufficiency (PaO(2)/FIO(2)<200) 38% versus 12% (0.704); proven and suspected bacterial infection 9% versus 1% (0.900) and 24% versus 1% (0.897), respectively. For CRP, the respective areas under the curve were all below 0.63, while all patients had elevated CRP levels, whether they had a complication or not.

CONCLUSIONS

Elevated PCT, but not CRP, correlates with evidence of systemic inflammation and other complications early postoperatively after cardiac surgery. Although the PCT levels do not rise as quickly as the criteria of the systemic inflammatory response syndrome appear, they do reflect systemic inflammation. Early identification and quantification of a systemic inflammatory response may help reduce postoperative complications.

Markers of endothelial damage in organ dysfunction and sepsis

OBJECTIVES

To review the literature on direct and indirect markers of endothelial activation and damage in patients with sepsis and systemic inflammation and to assess their clinical usefulness for diagnosis and outcome. Various markers derived from or activated by endothelial cells are described, such as adhesion molecules, thrombomodulin, von Willebrand factor, parameters of the coagulation system, and interleukin-6. Furthermore, the association of these markers with the severity of sepsis, systemic inflammation, and outcome is evaluated.

DATA EXTRACTION AND SYNTHESIS

Published research and review articles related to these parameters, with special emphasis on clinical studies.

CONCLUSIONS

Endothelial activation and damage occur early during sepsis and play a major role in the pathophysiology of systemic inflammation. Various markers of endothelial activation are increased during sepsis and systemic inflammation, and in most studies, the level of markers such as soluble intercellular adhesion molecule, vascular cell adhesion molecule, and E selectin correlate well with the severity of inflammation and the course of the disease. However, to date, it remains unclear whether adhesion molecules and coagulation parameters are superior in this respect to interleukin-6 and procalcitonin, as direct comparisons are lacking. In addition, it is evident that markers of endothelial activation and coagulation parameters lack specificity for infection-induced endothelial damage and organ dysfunction.

Statistical cost-effectiveness analysis of two treatments based on net health benefits

Statistical methods for cost-effectiveness analysis (CEA) for two treatments that mimic the deterministic optimal rules of CEA are presented. In these rules the objective is to determine the treatment with the maximal effectiveness whose unit cost is less than an amount, lambda, that a decision-maker is willing to pay (WTP). This is accomplished by identifying the treatment with the largest positive net health benefit (NHB), which is a function of lambda, while controlling the familywise error rate both when the WTP value is given and when it is unspecified. Fieller's theorem is used to determine a region of WTP values where the NHBs of the treatments are not distinguishable. For each lambda outside of the confidence region, the larger treatment is identified. A newly developed one-tailed analogue of Fieller's theorem is used to determine the WTP values where a treatment's NHB is positive. The situation in which both treatments are experimental is distinguished from the case where one of the treatments is usual care. The one-tailed confidence region is used in the latter case to obtain the lambda values where the NHBs are not different, and determining the region of positivity of the NHBs may be unnecessary. An example is presented in which the cost-effectiveness of two antipsychotic treatments is evaluated.

Plasma concentrations and clearance of procalcitonin during continuous veno-venous hemofiltration in septic patients

We determined the elimination characteristics of procalcitonin (PCT) during continuous veno-venous hemofiltration (CVVHF) and the resulting effect on PCT plasma levels. A prospective study was conducted in patients with sepsis and acute oliguric renal failure, treated with CVVHF using a polysulfone membrane (Baxter Renaflo II PSHF 1200). Patients had sepsis and PCT plasma levels > 4 ng ml(-1) (n = 26). PCT was measured in the pre- and post-filter plasma and the ultrafiltrate at 0, 5, 10, and 15 min and 1, 2, 4, 6, 12, and 24 h after setup of CVVHF. PCT sieving coefficient was 0.24. Elimination of PCT, however, depended on the duration of filtration, because filter adsorption was the main mechanism of PCT clearance during the first hour of hemofiltration, finally increasing to a clearance of PCT into the ultrafiltrate of 2.8-5.5 mL/min after 2 h. PCT plasma levels were not significantly altered during CVVHF (96% of the initial concentration after 24 h, P = 0.72). Similar to what has been observed with cytokines and other proteins of a comparable molecular weight, PCT is removed from the plasma during CVVHF, but plasma PCT levels are unchanged. Thus, PCT can be used as a diagnostic parameter even in patients with acute renal failure undergoing CVVHF.

[Leukocytopenia as an incidental finding. Finding the etiology]

Any leukopenia of less than 1000/microliter poses an acute threat to life, and mandates an immediate search for the underlying cause. An extensive history-taking (use of drugs? visits abroad? previous illnesses?) and physical examination (splenomegaly? exanthema? signs of hemorrhage?) are mandatory. In addition to a manual differential blood count, bone marrow aspiration for cytological and histological evaluation must be requested. In this overview, the major differential diagnoses, such as allergic agranulocytosis, leukemia, pernicious illnesses (e.g. malaria), hypersplenic syndrome and a number of infectious diseases are discussed.

The plasma elimination rate and urinary secretion of procalcitonin in patients with normal and impaired renal function

BACKGROUND AND OBJECTIVE

The amount of procalcitonin eliminated in the urine and the plasma disappearance rate of procalcitonin were evaluated in patients with normal and impaired renal function, because patients with sepsis are a main target group for procalcitonin measurement, and these patients often develop renal dysfunction.

METHODS

Elimination of procalcitonin in the urine (microgram 12 h-1) was measured in 76 patients. In another 67 patients, the 50% plasma disappearance rate (t1/2, h) was evaluated 48 h after peak concentrations (procalcitonin > 2 micrograms L-1). Renal function was assessed by creatinine clearance.

RESULTS

Procalcitonin elimination in the urine was significantly reduced in patients with severe renal dysfunction. However, the plasma disappearance rate correlated only weakly with renal dysfunction (Spearman's rank correlation R = -0.36, P = 0.004, regression t1/2 = 49.87-0.15 creatinine clearance). The 25% quartile and median were 25.2 h and 30.0 h in patients with normal renal function, and 36.3 h and 44.7 h in patients with severely impaired renal function (creatinine clearance < 30 mL min-1).

CONCLUSIONS

Renal elimination of procalcitonin is not a major mechanism for procalcitonin removal from the plasma. Although the plasma disappearance rate may be prolonged up to 30-50% in some patients with renal dysfunction, clinical diagnostic decisions may not be severely influenced by this moderate prolongation of procalcitonin elimination. We conclude that procalcitonin can be used diagnostically in patients with renal failure as well as in those with normal renal function.

Elimination of procalcitonin and plasma concentrations during continuous veno-venous haemodiafiltration in septic patients

The elimination of procalcitonin and the course of plasma concentrations during continuous veno-venous haemodiafiltration were measured in patients with sepsis or multiple organ dysfunction syndrome, because these patients are a main target group for the measurement of procalcitonin and often require renal replacement therapy. Procalcitonin was measured in the prefilter plasma and the filtrate at 5 min, 15 min and 1, 2, 4, 6, 12, 24 h after set-up of continuous veno-venous haemodiafiltration. In a prospective study, 19 patients with plasma levels of procalcitonin > 3 ng mL-1 and acute oliguric renal failure treated with continuous veno-venous haemodiafiltration using a polysulphone membrane, were evaluated for the study of clearance. Twenty-one control patients (procalcitonin < 2 ng mL-1) were studied to determine whether filtration itself induced a procalcitonin response. No interventions were required. In patients with low procalcitonin concentrations (procalcitonin < 2 ng mL-1) continuous veno-venous haemodiafiltration did not cause a rise in procalcitonin. In patients with increased procalcitonin plasma concentrations (> 3 ng mL-1), the protein was removed through the polysulphone membrane, with a final clearance of 4 mL min-1 after the initial adsorption period (clearance 0.4-0.9 mL min-1 during the first hour of continuous veno-venous haemodiafiltration). Thus, on the average, approximately 10% of plasma concentrations were measurable in the filtrate ultimately. However, procalcitonin plasma levels were not significantly altered during continuous veno-venous haemodiafiltration (86% of the initial concentration after 24 h). Although procalcitonin is removed from the plasma during continuous veno-venous haemodiafiltration in measurable amounts plasma procalcitonin concentrations did not change significantly during haemodiafiltration. Procalcitonin thus can also be used as a diagnostic parameter in patients undergoing continuous veno-venous haemodiafiltration.

Clinical experiences with a new semi-quantitative solid phase immunoassay for rapid measurement of procalcitonin

A self-developing solid-phase immunoassay (B.R.A.H.M.S. PCT-Q, B.R.A.H.M.S.-Diagnostica GmbH, Hennigsdorf, Germany) has recently become available for the semi-quantitative and rapid measurement of procalcitonin (PCT). In this study we examined the validity of this assay at daily clinical routine conditions at five different hospitals in a prospective study. After development of the assay (200 microl plasma, 30 minutes incubation), PCT levels were categorized into four groups (< 0.5 microg/l; > or = 0.5-< 2 microg/l; > or = 2-< 10 microg/l; > or = 10 microg/l) according to the provided reference scale. Samples from patients with suspected elevation of PCT of different etiology (n=237) were read by various analyzers and compared with the results of the Lumitest PCT (B.R.A.H.M.S.-Diagnostica GmbH, Hennigsdorf, Germany). A total of 74.7% of measurements were categorized according to the results of the LumitestPCT, 24.5% were read within the next lower or higher category. Using a +/- 10% range at the reference concentrations (20% at 0.5 microg/l), 82.7% of samples were correctly categorized and 16.4% within the next categories. Using a cut-off value of 2.0 microg/l, 92.0% (94.1% for +/- 10%) of the results were correctly categorized. The semi-quantitative solid phase immunoassay allows a rapid, simple and semi-quantitative measurement of plasma PCT. The validity of the test results and its ease of use are sufficient to support acute diagnostic decisions. However, for the follow-up of PCT concentrations and routine daily measurements, the quantitative luminometric assay should be preferred, when available.

Modulation of the ceramide level, a novel therapeutic concept?

The sphingomyelin (SM) pathway is an ubiquitous and evolutionarily conserved signaling system in which ceramide (CA), generated from SM by the action of various isoforms of sphingomyelinases (SMases) functions as an important second messenger. Recent evidence suggests that branching pathways of sphingolipid metabolism mediate either apoptotic or mitogenic responses depending on cell type and the nature of the stimulus. Events involving SM metabolites and CA in particular include proliferation, differentiation and growth arrest as well as the induction of apoptosis. An improved understanding of SMase-dependent signaling may afford relevant insights into the pathogenesis of diseases and provide novel strategies and selective targets for a therapeutic intervention e.g. in cancer, cardiovascular and neurodegenerative diseases, HIV and septic shock. This article briefly summarizes the role of SMases in signaling pathways, its potential contribution in the development and maintenance of various pathobiological states and analyzes the perspective of a potentially isotype-specifc inhibition of SMases as a novel therapeutic concept.

Influence of pyrrolidine dithiocarbamate on the inflammatory response in macrophages and mouse endotoxin shock

To analyze the immunomodulatory effect of pyrrolidine dithiocarbamate (PDTC) on the endotoxin (LPS) stimulated inflammatory response, we measured the LPS-stimulated cytokine and NO production in murine peritoneal macrophages, J774A.1 cells and human whole blood in the presence of PDTC (60 microM). PDTC significantly inhibited the production of nitrite, IL-1beta and IL-6 in these cells. TNFalpha release was stimulated in murine cells, but suppressed in human whole blood. We further investigated the influence of PDTC on mortality and cytokine release in mouse endotoxin shock. PDTC was i.p. injected 30 min prior to the induction of endotoxin shock in female NMRI-mice and survival was significantly improved as compared to controls (48% vs 20%, n=25 per group). Plasma concentrations of TNFalpha were slightly augmented while IL-6 levels were decreased in PDTC-treated animals as compared to controls, however, without reaching significance. We conclude that PDTC is a potent immunomodulatory substance that modulates the inflammatory response in vitro and reduces mortality in mouse endotoxin shock. The pathophysiological mechanisms of the protective effect of PDTC in vivo, however, appears to be pluripotent, comprising both antioxidative properties and the inhibition of NF-kB.

Power and sample size in cost-effectiveness analysis

For resource allocation under a constrained budget, optimal decision rules for mutually exclusive programs require that the treatment with the highest incremental cost-effectiveness ratio (ICER) below a willingness-to-pay (WTP) criterion be funded. This is equivalent to determining the treatment with the smallest net health cost. The designer of a cost-effectiveness study needs to select a sample size so that the power to reject the null hypothesis, the equality of the net health costs of two treatments, is high. A recently published formula derived under normal distribution theory overstates sample-size requirements. Using net health costs, the authors present simple methods for power analysis based on conventional normal and on nonparametric statistical theory.

Ratio-based and net benefit-based approaches to health care resource allocation: proofs of optimality and equivalence

Both incremental cost-effectiveness ratios and net benefits have been proposed as summary measures for use in cost-effectiveness analyses. We present a unifying proof of the optimality and equivalence of ICER- and net benefit-based approaches to the health resource allocation problem, including both 'fixed budget' and 'fixed price' decision rules. If internally consistent willingness-to-pay values are used, ratio- and net benefit-based decision rules identify the same optimal allocation. Because they have identical resource allocation implications, use of one or other of the two approaches must be based on other criteria, such as their behaviour under conditions of uncertainty.

Postoperative plasma concentrations of procalcitonin after different types of surgery

OBJECTIVE

Procalcitonin (PCT) and C-reactive protein (CRP) plasma concentrations were measured after different types of surgery to analyze a possible postoperative induction of procalcitonin (PCT), which might interfere with the diagnosis of bacterial infection or sepsis by PCT.

DESIGN

PCT and CRP plasma levels as well as clinical symptoms of infection were prospectively registered preoperatively and 5 days postoperatively.

SETTING

University hospital, in-patient postoperative care.

PATIENTS

Hundred thirty patients were followed up; 117 patients with a normal postoperative course were statistically analyzed.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

PCT concentrations were moderately increased above the normal range in 32 % of patients after minor and aseptic surgery, in 59 % after cardiac and thoracic surgery, and in 95 % of patients after surgery of the intestine. In patients with an abnormal postoperative course, PCT was increased in 12 of 13 patients. CRP was increased in almost all patients.

CONCLUSIONS

Postoperative induction of PCT largely depends on the type of surgery. Intestinal surgery and major operations more often increase PCT, whereas it is normal in the majority of patients after minor and primarily aseptic surgery. PCT can thus be used postoperatively for diagnostic means only when the range of PCT concentrations during the normal course of a certain type of surgery is considered and concentrations are followed up.

Modulation of mouse endotoxin shock by inhibition of phosphatidylcholine-specific phospholipase C

During Gram-negative bacterial infections, lipopolysaccharide (LPS) interacts with monocyte/macrophage receptors, resulting in a host defense response. Activation of intracellular signal transduction pathways implicating various protein kinase and phospholipases is crucial in activating the transcription of genes encoding proinflammatory cytokines and inducible nitric oxide synthase (iNOS). In this article, we demonstrate that in mouse, endotoxin shock activation of phosphatidylcholine-specific phospholipase C (PC-PLC) plays a major role in controlling the inflammatory response. Inhibition of PC-PLC by the specific inhibitor tricyclodecan-9-yl-xanthogenate (D609) before LPS reduced the release of interleukin-1 beta, interleukin-6 and nitric oxide (NO) in vivo. In contrast, tumor necrosis factor-alpha serum levels were not altered by the pretreatment with D609. Consequently, survival from endotoxin shock of D609-treated animals was significantly improved compared with control animals (45% vs. 20%). Thus, inhibition of PC-PLC can reduce the inflammatory response to LPS and may serve as a novel approach to therapy of sepsis.

Classification of the effectiveness of combination treatments

According to FDA regulations, a combination drug is not efficacious unless each component contributes to the claimed effects. For a univariate endpoint, this implies that the combination at specific doses must be superior to each of its components at the same doses. More demanding is the property of synergy, in which the effect of the combination must be superior to the effect expected based on those of its components. If it is equal to those effects, it is additive, and if it is inferior, it is antagonistic. We give regions in the combination dose plane where these concepts are well defined. If the effect of the combination is greater than the greatest effect achievable by any of its components it is therapeutically synergistic. A combination can be antagonistic, yet its components can still contribute to the claimed effects. If it is additive, synergistic or therapeutically synergistic, its components must contribute to the claimed effects. We relate these concepts and provide designs and sequential procedures for determining whether a combination is therapeutically synergistic, synergistic, additive, antagonistic and contributing or antagonistic and non-contributing.

Estimating the size of a population from a single sample: methodology and practical issues

In contrast to classical capture recapture methods, the single-sample method of Laska, Meisner, and Siegel (1988) (LMS) enables estimation of the size of a population, N*, on the basis of a single survey. For example, it may be desired to estimate the unduplicated number of individuals served by a mental health center during the last year on the basis of a 1-week sample. The time since each of the sampled individuals last engaged in the activity that defines the population is ascertained. The LMS estimator of N* and its unbiasedness property are motivated in a simple way, and an improved LMS estimator is introduced if additional information is available. An empirical assessment of the procedure is made using mental health service data for which the true population size is known. The performance of the extended LMS estimator is a substantial improvement over the standard LMS estimator.

The usefulness of average cost-effective ratios

We demonstrate that average cost-effectiveness ratios (CERs) play an important role in the evaluation of the cost-effectiveness of treatments. Criticisms of the usefulness of CERs derive mostly from the context of resource allocation under a constrained budget in which some decisions are based on incremental CERs. However, we show that in many cases, these decision rules are equivalent to decision rules on CERs. This follows for mutually exclusive treatments first, because a treatment is eliminated by extended dominance if and only if there is a mixed treatment with a smaller CER, where the mixing parameter lies in a certain interval. Second, after elimination of treatments by dominance and by extended dominance, resources can be allocated in order of increasing CERs. Moreover, the CER is a parameter that characterizes clinical and economical properties of a treatment independent of its comparators.

Procalcitonin--influence of temperature, storage, anticoagulation and arterial or venous asservation of blood samples on procalcitonin concentrations

In this study we have analysed the influence of temperature and time of storage and of repeated freezing on procalcitonin plasma concentrations ex vivo. We have also analysed the difference of procalcitonin concentrations in arterial or venous blood samples and the influence of different anticoagulation techniques on procalcitonin concentrations (serum, EDTA-, lithium-heparin- or citrate plasma). At room temperature (25 degrees C) a loss of procalcitonin plasma concentrations of 6.4% +/- 2.6% (mean, 2 standard error of the mean) after 3 hours (4.6% +/- 5.2% at 4 degrees C) and 12.3% +/- 3.1% after 24 hours occurred (6.3% +/- 5.0% at 4 degrees C, n = 17 each). Comparing the procalcitonin concentrations of blood samples with different anticoagulants (n = 24 each), there was only a significant difference between procalcitonin concentrations in heparinized plasma and serum (+ 7.6%, difference of the mean). There was no significant influence of the blood sampling technique (arterial or venous line) and of repeated freezing/thawing cycles (up to 3 times) on the procalcitonin concentrations measured. Although the difference of sampling and storage of the blood on procalcitonin concentrations is not significant, multiple factors may act synergistically on the result of procalcitonin measurement. To keep variations of ex vivo conditions as minimal as possible, a standardized technique of anticoagulation, time and temperature of storage is recommended, e.g. the use of EDTA-plasma and storage at room temperature, when samples are measured within 4 hours after blood drawing.

History of violent behaviour and schizophrenia in different cultures. Analyses based on the WHO study on Determinants of Outcome of Severe Mental Disorders

BACKGROUND

Information on patterns and correlates of the violent behaviour of individuals with schizophrenia is largely limited to populations in developed countries. Data from a World Health Organization epidemiological study of schizophrenia and related disorders, the Determinants of Outcome of Severe Mental Disorders (DOSMD), presented an opportunity to study patterns of violence across multinational settings.

METHOD

Centres in 10 countries participated in the DOSMD study. An incidence sample of 1017 patients with schizophrenia who had their first-in-lifetime contact with a helping agency as a result of their psychotic symptoms was obtained. Data were available on their history of violent behaviour, substance use, and demographics.

RESULTS

The occurrence rate of assault in the entire cohort was 20.6 per hundred, but the rate was three times higher in the developing countries (31.5 per hundred) than in developed countries (10.5 per hundred). History of assault was associated with positive symptoms, such as excitement and auditory hallucinations, and with serious alcohol problems.

CONCLUSIONS

The cultural context and the specific characteristics of the disease in individuals with schizophrenia may interactively affect rates of violent behaviour.

Statistical inference for cost-effectiveness ratios

Methods for statistical inference for cost-effectiveness (C/E) ratios for individual treatment and for incremental cost-effectiveness (delta C/ delta E) ratios when two treatments are compared are presented. In a lemma, we relate the relative magnitude of two C/E ratios to the delta C/ delta E ratio. We describe a statistical procedure to test for dominance, or admissibility, that can be used to eliminate an inferior treatment. The one-sided Bonferroni's confidence interval procedure is generalized to the two-sided case. The method requires only that two confidence intervals be available, one for cost and one for effectiveness. We describe Fieller-based confidence intervals and show them to be shorter than Bonferroni intervals. When distribution assumptions hold and variance and covariance estimates are available, Fieller intervals are preferable. However, Bonferroni intervals can be applied in more diverse situations and are easier to calculate. A simple Bonferroni based technique, and a likelihood ratio statistic given by Siegel, Laska and Meisner, for testing the null hypothesis that the C/E ratios of two treatments are equal is presented. The approaches are applied to the data from a phase II clinical trial of a new treatment for sepsis considered previously by others.

Blood volume determination using hydroxyethyl starch: a rapid and simple intravenous injection method

OBJECTIVE

To develop and evaluate a new method for blood volume measurements using hydroxyethyl starch as a dilution marker.

DESIGN

Laboratory and clinical investigation.

SETTING

Neurosurgical operating rooms and anesthesiological laboratories of a university hospital.

PATIENTS

Twelve patients who underwent a neurosurgical operation.

INTERVENTIONS

Anesthesia and operations were carried out by physicians who were not involved in the study. In addition, blood samples were drawn from 50 volunteers.

MEASUREMENTS AND MAIN RESULTS

Blood volume measurements by the hydroxyethyl starch method were validated in vivo by comparison with a conventional carbon monoxide technique. Patients were intravenously injected with hydroxyethyl starch (100 mL) and received simultaneously an injection of carbon monoxide (50 mL) into a closed-circuit ventilation system. Blood samples obtained before and 5 mins after injection were analyzed for carboxyhemoglobin and glucose plasma concentrations after acidic hydrolysis of hydroxyethyl starch. Blood volume was calculated from the difference between glucose concentrations measured after hydrolysis in the plasma, before and after the addition of hydroxyethyl starch. In vitro, the hydroxyethyl starch method had an error and a precision of approximately 2%. In vivo, simultaneous measurements of blood volume using hydroxyethyl starch and carbon monoxide demonstrated a high correlation (r2 = .96, p < .001) between these methods. The mean difference between the two methods relative to their average value was 1.0 +/- 3.5%; the bias was 52.3 mL, and the 95% confidence interval was -64.0 to +168.7 mL.

CONCLUSIONS

Blood volume determination by the hydroxyethyl starch method is accurate and rapid and may enhance perioperative monitoring of fluid and blood therapy.

Statistical methods for cost-effectiveness analyses

A statistical framework is presented for examining cost and effect data on competing interventions obtained from an RCT or from an observational study. Parameters of the join distribution of costs and effects or a regression function linking costs and effects are used to define cost-effectiveness (c-e) measures. Several new c-e measures are proposed that utilize the linkage between costs and effects on the patient level. These measures reflect perspectives that are different from those of the commonly used measures, such as the ratio of expected cost to expected effect, and they can lead to different relative rankings of the interventions. The cost-effectiveness of interventions are assessed statistically in a two stage procedure that first eliminates clearly inferior interventions. Members of the remaining admissible set are then rank ordered according to a c-e preference measure. Statistical techniques, particularly in the multivariate normal case, are given for several commonly used c-e measures. These techniques provide methods for obtaining confidence intervals, for testing the hypothesis of admissibility and for the equality of interventions, and for ranking interventions. The ideas are illustrated for a hypothetical clinical trial of antipsychotic agents for community-based persons with mental illness.

Estimating population size when duplicates are present

Each of K mental health programmes reports the number of patients served in a year. The sum of these numbers, y, is an overcount because some patients are seen in more than one programme. Health care planners need to know the unduplicated number served by the mental health system. Thus, there is an unknown number, M, of distinct individuals who appear on one or more of K lists; some appear on multiple lists and the duplicates are not readily identifiable. Let X be the number of lists on which a randomly selected individual appears. When E(X) is known, y/E(X) is the natural estimator of M. We assume that we know the number of programmes, Xi, used by the ith individual in a random sample of recipients of service. Here, the intuitive estimator, Y/X has desirable statistical properties. We give confidence interval estimators for M. We apply the method to estimate the number of individuals served in 1991 by the mental health programmes in New York State.