Analysis of blood pressure waveform: a new method for the classification of hypertensive pregnancy disorders.
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Adult↗
Biomedical subjects
A Voss
Publications and source records attributed to A Voss.
Baroreflex sensitivity, heart rate, and blood pressure variability in hypertensive pregnancy disorders.
Hypertensive pregnancy disorders are a leading cause of perinatal and maternal morbidity and mortality. Heart rate variability (HRV), blood pressure variability (BPV), and baroreflex sensitivity (BRS) are relevant predictors of cardiovascular risk in humans. The aim of the study was to evaluate whether HRV, BPV, and BRS differ between distinct hypertensive pregnancy disorders. Continuous heart rate and blood pressure recordings were performed in 80 healthy pregnant women as controls (CON), 19 with chronic hypertension (CH), 18 with pregnancy-induced hypertension (PIH), and 44 with pre-eclampsia (PE). The data were assessed by time and frequency domain analysis, nonlinear dynamics, and BRS. BPV is markedly altered in all three groups with hypertensive disorders compared to healthy pregnancies, whereby changes were most pronounced in PE patients. Interestingly, this increase in PE patients did not lead to elevated spontaneous baroreflex events, while BPV changes in both the other hypertensive groups were paralleled by alterations in baroreflex parameters. The HRV is unaltered in CH and PE but significantly impaired in PIH. We conclude that parameters of the HRV, BPV, and BRS differ between various hypertensive pregnancy disorders. Thus, distinct clinical manifestations of hypertension in pregnancy have different pathophysiological, regulatory, and compensatory mechanisms.
Adult↗
Hospital infection control in Europe: evaluation of present practice and future goals.
The objective of this study was to assess current infection control practice in Europe and its structure, future research priorities, and how infection control should be organised. A questionnaire was sent to 223 hospital infection control physicians throughout Europe, of whom 54 in 18 countries responded. With respect to future research priorities in infection control in Europe, the largest proportion (69%) of the infection control specialists sampled expressed the need for standardisation of surveillance systems for international comparison of nosocomial infection rates. The results of this survey might help to create a basis for standardised guidelines which take into account European-wide interests.
Cross Infection↗
A European perspective on intravascular catheter-related infections: report on the microbiology workload, aetiology and antimicrobial susceptibility (ESGNI-005 Study).
The laboratory workload, microbiological techniques and aetiology of catheter-related infections in European hospitals are mostly unknown. The present study (ESGNI-005) comprised a 1-day (22 October 2001), laboratory-based, point-prevalence survey based on a questionnaire completed by microbiology laboratories in European (European Union (EU) and non-EU) hospitals. Also included were questions requesting retrospective information for the year 2000. In total, 151 hospitals from 26 European countries participated, of which 78.1% were teaching institutions. Overall, the estimated population served by these institutions was 121,363,800, and the estimated number of admissions during 2000 was 6,712,050. The total number of catheter tips processed during 2000 was 142,727, or 21/1,000 admissions, of which 23.7% were considered to be positive in the institutions using semiquantitative or quantitative techniques. Overall, EU centres received significantly more catheter tip samples/1,000 admissions and had a significantly higher rate of 'positivity' (p < 0.0001) than non-EU centres. Of the institutions surveyed, 11.4% (7.2% in EU countries and 23.7% in non-EU countries; p 0.04) used only qualitative techniques for catheter tip sample processing. On the day of the study, 167 microorganisms were recovered from significant catheter tip cultures (122 patients), of which Gram-positive bacteria represented 70.7%, Gram-negative bacteria 22.2%, and yeasts 7.2%. The five most common microorganisms were coagulase-negative staphylococci, Staphylococcus aureus, Candida spp., Enterococcus spp. and Pseudomonas spp. Overall, 19% of catheter tip cultures were polymicrobial. In the case of S. aureus, 40% of isolates were resistant to oxacillin, as were 63.4% of coagulase-negative staphylococcus isolates. Of 37 Gram-negative isolates, 35% were resistant to cefotaxime, 31% to ceftazidime, and 27% to ciprofloxacin. Imipenem and cefepime had the lowest reported rates of resistance (11%).
Anti-Bacterial Agents↗
Clinical-epidemiological characteristics and outcome of patients with catheter-related bloodstream infections in Europe (ESGNI-006 Study).
This study analysed 89 episodes of catheter-related bloodstream infection (CR-BSI) occurring during one week in 107 hospitals from 21 European countries (1.02 episodes/1,000 admissions). Patients from European Union (EU) countries had a higher incidence of CR-BSI than patients from non-EU countries (1.55 vs. 0.33/1,000 admissions). Most (67%) catheters were non-tunneled central venous catheters, were in the jugular vein (44%), had been implanted for > 7 days (70%), were made of polyurethane (61%) and were multi-lumen (67%). In 36% of cases, catheters were implanted by physicians other than anaesthetists or surgeons, and 50% were inserted by junior staff.
Bacteremia↗
A putative regulatory polymorphism in PD-1 is associated with nephropathy in a population-based cohort of systemic lupus erythematosus patients.
The association between polymorphisms in the programmed death (PD-1) gene and susceptibility to systemic lupus erythematosus (SLE) was determined using genomic DNA, isolated from a population-based cohort of 95 SLE patients and 155 healthy controls. Polymorphisms in the complete PD-1 gene except the large intron 1 were detected by sequencing. Furthermore, the patients were stratified according to the presence or absence of lupus nephropathy. The influence of the detected single nuclear polymorphisms (SNPs) on this specific clinical disease parameter was determined. In total, we identified 12 single nucleotide polymorphisms, of which six were novel and eight were considered to be rare (the frequency of the minor allele of these was less than 1% in our study populations). We found a significant association of an intronic 6867C/G SNP in the PD-1 gene with the presence of lupus nephropathy. As the 6867C/G SNP is located in a putative binding site for the transcriptional repressor ZEB, the associated allele of this SNP potentially alters the transcriptional regulation of PD-1. This report, for the first time, indicates that a 6867C/G SNP of the PD-1 gene is associated with lupus nephropathy in Caucasian SLE patients.
Adolescent↗
Autoantibodies and self-reported health complaints in relatives of systemic lupus erythematosus patients: a community based approach.
First-degree relatives (FDRs) and spouses to a population-derived cohort of lupus patients were investigated for the occurrence of selected autoantibodies and self-reported health complaints. A healthy reference population was included. The lupus population consisted of 103 index cases. A total of 275/375 available relatives accepted to enter the study. Two hundred and twenty-six/315 (72%) were FDRs and 49/60 (82%) were spouses. Serum was analysed for ANA using indirect immunofluorescence on Hep-2 cells at the following dilutions: 1:40, 1:80 and 1:160 and in addition sera were tested for anti-dsDNA, IgM RF, ACA (IgM, IgG), anti-beta2GPI (IgM, IgG) and antibodies to prothrombin. ANA positivity occurred more frequently in FDRs compared with spouses and controls at serum dilution 1:160 (10 versus 0% and 2.5%, respectively, P = 0.04 and P < 0.01), 1:80 (24 versus 4% and 5%, respectively, P = 0.003 and P < 0.001) and 1:40 (31 versus 10% and 10%, respectively, P = 0.006 and P < 0.0001). ANA positivity in FDRs occurred randomly, irrespective of family relationship. Fifty-three/184 versus 2/32 FDRs to patients with definite SLE (D-SLE) and incomplete SLE (I-SLE), respectively, tested ANA positive at 1:80 (P < 0.05). FDRs with ANA titer at 80 were affiliated to lupus probands with high SLICC scores (P < 0.05). Self-reported health complaints, cardiovascular/thromboembolic events in particular, were more frequent among FDRs than in spouses. The population-based approach adopted in the present study supports previous clinic-based evidence of an increased propensity for autoantibody occurrence in relatives to SLE patients. In FDRs, present ANA positivity was associated with increased prevalence of health complaints and ANA positivity in FDRs was related to the criterial burden and cumulated damage in corresponding lupus probands. The low ANA frequency among spouses of SLE patients argues against a significant autoantibody triggering effect of shared environment in adult life.
Adult↗
Estimating respiratory pattern variability by symbolic dynamics.
OBJECTIVES: The traditional techniques of data analysis are often not sufficient to characterize the complex dynamics of respiration. In this study the respiratory pattern variability was analyzed using symbolic dynamics. METHODS: A group of 20 patients on weaning trials from mechanical ventilation were studied at two different pressure support ventilation levels. Breath duration (T(TOT)) time series and the relation T(I)/T(TOT), that contains the influence of inspiratory time (T(I)), were considered. Length-3 words and 3 different symbols were proposed. The incidence of the overlapping tau and the parameter alpha were analyzed. RESULTS: From the breath duration time series, the distribution of words with probability of occurrence higher than 6% was concentrated on one word for low respiratory variability, whereas high variability was characterized by 4 words, presenting a statistically significant difference (p </= 0.0005). The probability occurrence of words "110" and "111" was also significantly different (p</= 0.0005) when comparing both variabilities. CONCLUSION: The analysis carried out obtained discriminant functions able to correctly classify all the testing set series. These results permit the consideration of symbolic dynamics as a promising methodology to study the respiratory pattern variability.
Data Interpretation, Statistical↗
Forecasting of life threatening arrhythmias using the compression entropy of heart rate.
OBJECTIVES: Ventricular tachycardia (VT) provoking sudden cardiac death (SCD) are a major cause of mortality in the developed countries. The most efficient therapy for SCD prevention are implantable cardioverter defibrillators (ICD). In this study heart rate variability (HRV) measures were analyzed for short-term forecasting of VT in order to improve VT sensing and to enable a patient warning of forth-coming shocks. METHODS: The last 1000 normal beat-to-beat intervals before 50 VT episodes stored by the ICD were analyzed and compared to individually acquired control time series (CON). HRV analysis was performed with standard parameters of time and frequency domain as suggested by the HRV Task Force and furthermore with a newly developed and optimized nonlinear parameter that assesses the compression entropy of heart rate (Hc). RESULTS: Except of meanNN (p = 0.02) we found no significant differences in standard HRV parameters. In contrast, Hc revealed highly significant (p = 0.007) alterations in VT compared with CON suggesting a decreased complexity before the onset of VT. CONCLUSION: Compression entropy might be a suitable parameter for short-term forecasting of life-threatening tachycardia in ICD.
Arrhythmias, Cardiac↗
Two cases of subcutaneous Scedosporium apiospermum infection treated with voriconazole.
Scedosporium apiospermum is a mold that is increasingly being recognized as an opportunistic pathogen in immunocompromised patients, and treatment is complicated by intrinsic resistance to several antifungal agents. In our hospital, two cases of S. apiospermum infection occurring within 2 weeks were successfully treated with voriconazole. Since both patients were infected with an uncommon pathogen, a search for a common nosocomial source was performed. As environmental cultures yielded no S. apiospermum, and random amplified polymorphic DNA (RAPD) fingerprinting showed that the patients' strains were genotypically unrelated, we considered a common nosocomial source of S. apiospermum to be unlikely.
Aged↗
Should we routinely disinfect floors?
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Attitude of Health Personnel↗
Working IT out in medical practice: IT systems design and development as co-realisation.
OBJECTIVES: The paper explores possibilities for situating IT design and development work within the context of use so as to support the co-realisation of technology and 'design in use'. The aim is to build a new understanding between IT professionals and users which is grounded upon what happens as the latter grapple with the problems of applying IT, appropriating its functionalities and affordances into their work practices and relations. METHODS: Following a discussion of participatory design and ethnomethodology, a novel method called co-realisation, which aims to provide a synthesis of the preceding methods, is suggested as an alternative. Through a discussion of findings from a case study of IT systems design and development in healthcare we show how the co-realisation approach might provide work-affording systems and how user-designer relations might be reformulated. We suggest that work-affording systems can be developed through the deployment of an engaged facilitator who works with the users to unpack the work site-specific potentialities of technology. RESULTS: The case study shows how risk of non-adoption might be minimised through the development of partnerships, and how the presence of the facilitator in the workplace capitalises on the mundane work undertaken therein and how the facilitator might work with the users to develop artefacts that support this work as opposed to reconfiguring it. CONCLUSIONS: The case study illustrates co-realisation in action and how it might be seen to reconfigure relations between users and designers in a way that appears productive. Co-realisation can help address the widely observed problem of IT systems failures in healthcare.
Ambulatory Care Information Systems↗
Severe acute respiratory syndrome: lessons and uncertainties.
The outbreak of severe acute respiratory syndrome (SARS) has produced scientific and epidemiological discoveries with unprecedented speed, and this information has been spread instantaneously to the global health community through the internet. Within a few weeks, the coronavirus associated with SARS (SARS-CoV) was identified and sequenced. The source of the outbreak and the exact modes of transmission are still subjects of research. Important lessons can be learned from the SARS outbreak about both the scientific and the public health approach to emerging pathogens.
Disease Outbreaks↗
Joint symbolic dynamic analysis of beat-to-beat interactions of heart rate and systolic blood pressure in normal pregnancy.
Pregnancy induces important changes in the autonomic control. Measures of heart rate (HR) variability and systolic blood pressure (SP) variability are sensitive to those changes. The interactions between HR and SP are complex and strongly non-linear. Therefore they cannot be completely described by linear analysis techniques. A study of joint symbolic dynamics is presented as a new short-term non-linear analysis method to investigate the interactions between HR and SP. Continuous, non-invasive 30 min blood pressure recordings (Portapres) of 25 pregnant and 14 non-pregnant women were analysed. Time series of beat-to-beat HR and SP were extracted. Using the concept of joint symbolic dynamics, HR and SP changes were transformed into a bivariate symbol vector. Subsequently, this symbol vector was transformed into a word series (words consisting of three successive symbols), and the probability of occurrence of each word type was calculated and compared between both groups. Significant differences were found in five word types between pregnant and non-pregnant women: w0,4(0.021+/-0.011 against 0.008+/-0.006; p = 0.022), w4,6(0.020+/-0.010 against 0.007+/-0.003; p = 0.001), w3,2(0.004+/-0.003 against 0.007+/-0.003; p = 0.038), W6,5(0.009+/-0.007 against 0.023+/-0.008; p< 0.001) and w3,6(0.011+/-0.007 against 0.023+/-0.008; p = 0.001). Joint symbolic dynamics provides an efficient non-linear representation of HR and SP interactions that offers simple physiological interpretations.
Adult↗
Laboratory diagnosis and biosafety issues of biological warfare agents.
Bioterrorism events have been rare until recently. Many clinical laboratories may not be familiar with handling specimens from a possible bioterrorism attack. Therefore, they should be aware of their own responsibilities and limitations in the handling and treatment of such specimens, and what to do if they are requested to process clinical samples. The Centers for Disease Control and Prevention has developed the Laboratory Response Network to provide an organized response system for the detection and diagnosis of biological warfare agents based on laboratory testing abilities and facilities. There are potentially many biological warfare agents, but probably a limited number of agents would be encountered in case of an attack, and their identification and laboratory safety will be discussed.
Biological Warfare↗
Exploring a repetitive training regime for upper limb hemiparesis in an in-patient setting: a report on three case studies.
PRIMARY OBJECTIVE: To explore the efficacy of a task-oriented repetitive training protocol (RTx) in chronic hemiparetic patients in an in-patient rehabilitation unit. RESEARCH DESIGN: Three case studies; ABAB design (A=RTx; B=regular rehabilitation programme; 1 week per phase, respectively) in case P1, pre-post intervention comparison in case P2; repeated measure design in case P3. METHODS AND PROCEDURES: Daily training of task-oriented affected hand movements using shaping procedures developed in Constraint-Induced (CI) Movement Therapy. Patients 1 and 2 were trained daily for 90 minutes over 2 weeks. Patient 3 received 60 minutes of daily training for a period of 4 weeks. Outcome measures were Wolf Motor Function Test (WMFT), Frenchay Arm Test, nine-hole peg test, upper extremity MRC, and grip force. MAIN OUTCOMES AND RESULTS: Substantial clinical benefits were achieved in all patients. The subjective observations mirrored significant improvements in the outcome parameters. CONCLUSION: The affected hand training improves upper limb motor functions in chronic patients. It is a 'practicable' approach for in-patient rehabilitation units.
Adolescent↗
[Modified interaction of blood pressure and heart rate in idiopathic dilated cardiomyopathy].
BACKGROUND: Neurovegetative and haemodynamic changes impact on the regulation pattern of blood pressure and heart rate in patients with heart failure. We studied these patterns and their interactions in patients with idiopathic dilated cardiomyopathy (IDC) and in healthy subjects (REF). METHODS: We continually measured the heart rate and blood pressure (Portapres device) in twenty-five supine IDC patients (age: 51 +/- 13 y; left ventricular end-diastolic diameter 67 +/- 11 mm; ejection fraction 30 +/- 11%) and in twenty-seven REF (age: 50 +/- 11 y) Recording time was 30 minutes. The heart rate (HR) of each beat and the systolic blood pressure (SYS) of the subsequent beat were measured. Code numbers (symbols) were assigned to the beat-to-beat changes in HR and SYS (increase: 1; decrease: 0). The frequencies of the symbols sequences of three successive beats were counted. In this way we obtained a matrix consisting of eight (two to the power of three) HR and SYS combinations: 000, 100, 010, 001, 111, 110, 011 and 101. We then counted the frequencies of the different combinations of the symbol sequences in HR and SYS (2(3) x 2(3) = 64 combinations). The relative frequencies of symbol patterns appearing in HR, SYS and in the combined analysis of HR and SYS, were compared for IDC and REF using the T-test for independent samples. RESULTS: Significant differences were seen between IDC and REF. The HR patterns 101 and 010 were more frequent in IDC than in REF patients (11.1 +/- 4.7 vs. 7.7 +/- 2.9%, p = 0.003, and 16.1 +/- 6.3 vs. 11.7 +/- 4.9%, p = 0.008). This finding was even more marked in the analysis of the SYS patterns 101 and 010 (11.0 +/- 7.4 vs. 8.2 +/- 2.9%, p < 0.001, and 11.6 +/- 7.4 vs. 5.4 +/- 2.7%, p < 0.001). Non-alternating patterns were more frequent in REF (e.g. 000HR & 111SYS: 4.6 +/- 3.3 vs. 2.9 +/- 2.4%, p = 0.03). CONCLUSIONS: We demonstrated significant interaction of the regulation patterns of blood pressure and heart rate, as also their interactions in IDC. Opposed changes in HR and SYS mediated by the baroreflex, became superimposed by alternans phenomena in IDC. The pattern analysis of changes in HR and SYS detects these disturbances of neurovegetative short-term control.
Aged↗
[Quantitative analysis of cardiovascular interactions in patients with cardiomyopathy and after myocardial infarct].
The aim of this study was to detect pathological changes of the complex autonomous regulation of ecg, blood pressure and respiration (synchronously recordings of 30 minutes) in patients with cardiac diseases. We investigated the cardiovascular and cardiorespiratory linear and nonlinear interactions in 10 patients with dilative cardiomyopathy (dcm) and in 10 patients after myocardial infarction (mi). We compared results from the classical linear correlation function analysis with results from the mutual information method (transinformation) for analysis of nonlinear and linear interactions. Both methods yield high significant parameters (p < 0.01). Thus, we found both linear and nonlinear interactions with partly different specificity in patients with dcm and mi compared to healthy subjects (ref).
Blood Pressure Monitors↗