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S Sandberg

Publications and source records attributed to S Sandberg.

At least 19 recordsLinked to original sources
PubMed2006

Measurement of the tensile strength of the ventral abdominal wall in comparison with scar tissue.

BACKGROUND: Paramedian laparotomies lead to incisional hernias in approximately 30% of cases. In contrast, incisional hernias occur very rarely in the linea alba or the ventral abdominal wall. In this setting we investigated the difference between scar tissue and the non-incised abdominal wall tissue. METHODS: At the post mortem examination of 66 recently deceased individuals, accurately measured pieces of resected tissue from the linea alba, the anterior and the posterior rectus sheath, and scar tissue following median laparotomy, were exposed to tensile loads. FINDINGS: In the epigastric region the tissue ruptured at a mean horizontal load of 10.0 (SD 3.4) N/mm(2) in the linea alba and 6.9 (SD 2.5) N/mm(2) in scar tissue (P<0.001), and at a mean vertical load of 4.5 (SD 2.0) N/mm(2) in the linea alba and 3.3 (SD 1.6) N/mm(2) in scar tissue (P<0.05). In the hypogastric region as well, scar tissue was significantly less resistant in the main direction of load. INTERPRETATION: Scar tissue has a significantly lesser loading capacity than the intact ventral abdominal wall and therefore poses a permanent risk for herniation. For this reason, closure of the abdominal wall should be given due consideration and subjected to further investigation. Specifically, sustained reinforcement of scar tissue by means of suture techniques or non-absorbable sutures warrants further study. When constructing meshes for reinforcement of incisional hernias, the two-fold tensile load on the midline in horizontal direction as opposed to the craniocaudal direction must be taken into account.

Abdominal Wall↗
PubMed2006

External quality assessment of prothrombin time: the split-sample model compared with external quality assessment with commercial control material.

OBJECTIVE: CoaguChek S is a point-of-care, whole-blood, prothrombin time monitor. The purpose of this study was to compare two different methods for external quality assessments of CoaguChek S. MATERIAL AND METHODS: In the traditional external quality assessment scheme, commercial control material was sent to office laboratories and the results were compared with a method-specific target value. In the alternative external quality assessment (the split-sample survey) patient samples were analyzed on CoaguChek S at office laboratories, and venous blood samples from the same patients were analyzed at a hospital laboratory using an assigned comparison method. To obtain comparable performance criteria for the two methods, the limits for "good", "acceptable" and "poor" performance evaluation in the split-sample survey had to be expanded because of uncertainties in preanalytical factors and the comparison method. RESULTS: In the traditional external quality assessment the total imprecision (between-office and within-office) was 8.0% at the low level (1.6 INR (International Normalized Ratio)) and 10.5% at the therapeutic level (3.4 INR). In the split-sample survey the total imprecision was 12.3% at the low level (2.1 INR) and 10.7 % at the high level (3.0 INR). Seventy-five percent of the participating office laboratories were characterized as "good" with the traditional external quality assessments, whereas the corresponding number was 73% using the split-sample model. CONCLUSIONS: Available commercial control material for CoaguChek S is different from patient samples. This study demonstrates that split-sample survey is achievable, and is an acceptable alternative to traditional external quality assessment for point-of-care prothrombin time monitors where appropriate control material is difficult to obtain.

International Normalized Ratio↗
PubMed2004

Urine analysis and decision-making on cystitis in general practice.

Decision-making on cystitis in general practice was studied by addressing 1171 general practitioners of whom 909 responded. A case history was supplied with a test-strip result where leucocyte esterase was 1 + and the nitrite field either positive or negative. The respondents' estimated probability of urinary tract infection from the history had a median at 50% (10 and 90 percentiles, 30% and 90%). The test-strip results changed the estimate to 90% (50% and 100%) in the nitrite-positive group and 50% (10% and 90%) in the nitrite-negative group. Likelihood ratio was calculated from each respondent's estimated pre- and post-test probability to express the test's assumed diagnostic power. The median likelihood ratios were 4.75 (10 and 90 percentiles, 1.00 and 35.70) in the nitrite-positive group and 1.00 (0.11 and 4.00) in the nitrite-negative group. The resulting actions taken by the respondents were: no action (14 respondents, corresponding median estimated post-test probability 27.5%), await further examination (482, 50%) and prescription of antibiotics (366, 90%). Further examination included urine microscopy (13%), bacteriologic culture (21%), or both (65%). Eight-two percent of respondents who decided to prescribe antibiotics would also perform further examinations. In routine urine analysis, 79% of respondents request only test strips, 2% perform microscopy and 19% do both. The estimated probability of urinary tract infection is significantly affected by test-strip results and is important for the choice of further actions. Microscopy is performed more often than recommended in other studies.

Adult↗
PubMed2004

A multicentre study of reference intervals for haemoglobin, basic blood cell counts and erythrocyte indices in the adult population of the Nordic countries.

Eight haematological quantities were measured in EDTA anticoagulated venous blood specimens collected from 1826 healthy male and female individuals between 18 and 90 years of age in the Nordic countries (Denmark, Finland, Iceland, Norway and Sweden). The samples, collected between November 1999 and November 2001 as part of the Nordic Reference Interval Project (NORIP), were analysed on 12 different types of modern automated haematology instruments currently in use among the 60 laboratories participating in the study. Non-parametric reference intervals (between 2.5 and 97.5 percentiles) have been calculated for B-Haemoglobin (females 117-153 g/L, males 134-170 g/L), B-Erythrocytes (females 3.94-5.16 x 10(12)/L, males 4.25-5.71 x 10(12)/L), B-EVF (females 0.348-0.459, males 0.395-0.500), B-MCV (82-98 fL), Erc-MCH (27.1-33.3 pg), Erc-MCHC (317-357 g/L), B-Trc (females 165-387 x 10(9)/L, males 145 x 348 x 10(9)/L) and B-Lkc (3.5-8.8 x 10(9)/L). Partitioning of data according to age and gender was done according to a standardized procedure. For most variables the calculated reference intervals corresponded well with older and less well-defined reference intervals. The mean concentration of B-Haemoglobin increased by 0.08 g/L per year of age in women, and decreased by 0.1 g/L per year of age in men. B-Haemoglobin increased with body mass index in both men and women. Smoking increased the mean of B-Lkc by 1.1 x 10(9)/L and regular use of alcohol increased the mean of B-MCV by 0.8 fL. The influence of these factors was small overall and did not promote specific reference intervals.

Adolescent↗
PubMed2004

Asthma exacerbations in children immediately following stressful life events: a Cox's hierarchical regression.

BACKGROUND: A recent prospective study of children with asthma employing a within subject, over time analysis using dynamic logistic regression showed that severely negative life events significantly increased the risk of an acute exacerbation during the subsequent 6 week period. The timing of the maximum risk depended on the degree of chronic psychosocial stress also present. A hierarchical Cox regression analysis was undertaken to examine whether there were any immediate effects of negative life events in children without a background of high chronic stress. METHODS: Sixty children with verified chronic asthma were followed prospectively for 18 months with continuous monitoring of asthma by daily symptom diaries and peak flow measurements, accompanied by repeated interview assessments of life events. The key outcome measures were asthma exacerbations and severely negative life events. RESULTS: An immediate effect evident within the first 2 days following a severely negative life event increased the risk of a new asthma attack by a factor of 4.69, 95% confidence interval 2.33 to 9.44 (p<0.001) [corrected] In the period 3-10 days after a severe event there was no increased risk of an asthma attack (p = 0.5). In addition to the immediate effect, an increased risk of 1.81 (95% confidence interval 1.24 to 2.65) [corrected] was found 5-7 weeks after a severe event (p = 0.002). This is consistent with earlier findings. There was a statistically significant variation due to unobserved factors in the incidence of asthma attacks between the children. CONCLUSION: The use of statistical methods capable of investigating short time lags showed that stressful life events significantly increase the risk of a new asthma attack immediately after the event; a more delayed increase in risk was also evident 5-7 weeks later.

Acute Disease↗
PubMed2003

Health technology assessment and implications for clinical practice: the case of prostate cancer screening.

We describe an initiative to disseminate evidence from systematic reviews about the clinical effectiveness of prostate cancer screening to general practitioners and urologists in Norway. The Norwegian Centre for Health Technology Assessment invited The Norwegian Medical Association, The Norwegian Cancer Society, The Norwegian Board of Health, The Norwegian Urological Cancer Group and The Norwegian Patient Association to develop and disseminate clinical practice recommendations. The clinical effectiveness of prostate cancer screening has been assessed in nine independent systematic reviews, which are summarized in a joint INAHTA report. The conclusion was that there is no evidence from appropriately designed trials that early detection and treatment of prostate cancer can reduce mortality, morbidity or improve quality of life. The number of prostate-specific antigen (PSA) tests analysed in Norway increased by 47% [corrected] from 1996 to 1999; at the county level the increase ranged from 12 to 48%. On this background we disseminated leaflets with information about PSA and prostate cancer to 4100 general practitioners and specialists in urology. The main message was, i) PSA should not be taken in healthy men, ii) if the test is wanted, the physician is obliged to give information about the possible consequences. Despite efforts to anchor the information campaign within the mentioned organizations, this met with notable opposition from The Norwegian Urological Society. A survey among agencies within the INAHTA network showed that more than half of the countries within this collaboration have implemented guidelines or recommendations on prostate cancer screening. In conclusion, evidence obtained through an international collaboration such as the INAHTA collaboration may be used to develop and implement national guidelines or recommendations.

Adult↗
PubMed2002

Positive experiences and the relationship between stress and asthma in children.

UNLABELLED: Ninety children aged 6 to 13 y and suffering from chronic asthma were included in a prospective follow-up study lasting 18 mo in order to assess whether life events involving substantial positive effects on the child can protect against the increased risk associated with stressful life events. The main outcome measures included positive life events, positive long-term experiences, severely negative life events, chronic psychosocial stress and new asthma exacerbation. The results showed that, provided they occurred in close proximity to severely negative life events, positive life events, generally related to the child's own achievements, afforded protection against the increased risk of a new asthma exacerbation precipitated by severe events in children whose lives were marked by low to medium levels of chronic stress. No such effect was found in children exposed to high chronic stress nor did long-term positive experiences, such as when the child has a rewarding hobby, affect the asthma risk. CONCLUSION: Life events with a definite positive effect can counteract the increased risk of an asthma exacerbation precipitated by a severely negative life event, provided the chronic stress is only of low to medium level. Because this protective influence does not apply where there is high chronic stress, reducing this condition must be seen as a priority in children suffering from asthma, as these children are also more vulnerable to negative life events precipitating asthma exacerbation.

Adolescent↗
PubMed2001

[Acute intermittent porphyria is a difficult diagnosis--especially in children].

BACKGROUND: Acute intermittent porphyria is a rare disease, and it is often confused with other diseases since the symptoms, abdominal pain, paresis and depression are rather common. The disease most often becomes manifest after puberty, but cases in childhood have been described. The present paper deals with a child with onset of acute intermittent porphyria at eight years of age. MATERIAL AND METHODS: This case story is based on journals from different hospitals and the diary of the father of the boy. The analytical methods are those commonly used at the National Centre for Porphyria in Norway. RESULTS: Six years passed from the debut of symptoms to the diagnosis acute intermittent porphyria was obtained, and the boy has now permanent paresis. Further examination of the family disclosed that both his father and brother were affected. INTERPRETATION: It is important to know that acute intermittent porphyria may even occur in children. There is established a National Centre for Porphyria in Norway. This centre will offer advice to patients and health care professionals concerning the diagnosing, treatment and prophylaxis of porphyria diseases.

Adolescent↗
PubMed2001

[Quality of rapid tests for determination of infectious mononucleosis].

BACKGROUND: The Norwegian centre for quality assurance in primary health care, NOKLUS, was established in 1992 to ensure the quality of laboratory analyses performed in primary health care. This article evaluates results from the surveys of infectious mononucleosis. MATERIAL AND METHODS: From 1996 to 2000, five serum panels were sent to participating practices in order to control test-kits designed for serological rapid diagnosis of infectious mononucleosis. 648 practices participated in this external quality assessment in 2000. Target values were determined using the Paul Bunell Davidsohn test. The results obtained for each type of test and variables that might have affected the results were evaluated. RESULTS: Outdated kits or kits close to the date of expiration showed poorer results than the other test-kits. The quality of the results depended mainly on the type of test-kit used and the training level of the persons performing the analyses. INTERPRETATION: The best performing tests in these surveys were Clearview IM (Unipath Limited) and Contrast Mono (Genzyme diagnostics). These two tests are among the three most frequently used tests, out of a total of thirteen, in our surveys.

Agglutination Tests↗
PubMed2001

External quality assessment of general practice laboratories: organizational issues and interpretation of feedback reports.

OBJECTIVE: To describe and evaluate organizational issues and handling of feedback reports in the Norwegian external quality assessment scheme (EQAS) for general practice laboratories. METHODS: Postal questionnaire survey including three EQAS feedback reports (one with acceptable analytical quality, one indicating a problem with precision and one indicating bias of the measurement method) to 535 randomly selected general practices. RESULTS: The response rate was 80%. Two-thirds of practices were group practices, and 16% of practices employed a medical technologist. Nearly all practices found the manual for analysing quality control material easy to understand, and samples seemed to be handled as part of routine laboratory work. Feedback reports were primarily studied by those responsible for laboratory work in the practice, and only in 60% of practices by doctors. Practice routines for follow-up of deviant results in the EQAS seemed to have been established. Internal quality control was performed in 90% of group practices and in 71% of solo practices. Concerning responses to feedback reports, there seemed to be a substantial need for assistance even for less deviant results, although most actions suggested by the practices were adequate. On the other hand, assistance was not always sought for "critical" problems. CONCLUSIONS: EQAS is feasible in primary care, but instructions must be clear and conclusions in the feedback reports made very explicit. Easy-to-reach assistance from medical technologists with expertise in general practice laboratory instruments and routines seems paramount.

Family Practice↗
PubMed2001

Influence of index of individuality on false positives in repeated sampling from healthy individuals.

The index of individuality is defined as the ratio of the within-subject biological variation to the between-subject variation, i.e., the variation between the biological set-points. It has been disputed whether the index of individuality has influence on the usefulness of conventional population-based reference intervals. In this investigation we found that, as long as only a single sample is taken, for a certain change in an individual's set-point, the index of individuality has no influence on the usefulness of reference intervals. When two or more samples are taken into account, however, the outcome of the measurement is highly dependent on the index of individuality. For a low index, repeat measurement has only limited effect on the fraction of false-positive results, as the next result will be close to the first, but, when the index is high, the fraction of false-positive results will be reduced considerably through repeating the test. Moreover, the distribution of biological set-points for which the fraction of false-positive results originate is described and the influence of analytical imprecision is discussed. The calculations are performed for values of the index of individuality from 0 to 2.0 for the traditional 95% reference interval based on x +/- 2*s(total) (s(total) = total biological variation), and also for a decision limit (cut-off point) x +/- 3*s(total). The numbers are, of course, different, but the effects of the index of individuality are the same, independent of the chosen cut-off point. This concept is related to the clinical classification (diagnosis, prognosis, screening) and the difference from different principles of monitoring is discussed. Further, five examples are evaluated and aspects of index of individuality in relation to false-positive results are discussed.

Analysis of Variance↗
PubMed2001

Models for combining random and systematic errors. assumptions and consequences for different models.

A series of models for handling and combining systematic and random variations/errors are investigated in order to characterize the different models according to their purpose, their application, and discuss their flaws with regard to their assumptions. The following models are considered 1. linear model, where the random and systematic elements are combined according to a linear concept (TE = absolute value(bias) + z x sigma), where TE is total error, bias is the systematic error component, sigma is the random error component (standard deviation or coefficient of variation) and z is the probability factor; 2. squared model with two sub-models of which one is the classical statistical variance model and the other is the GUM (Guide to Uncertainty in Measurements) model for estimating uncertainty of a measurement; 3. combined model developed for the estimation of analytical quality specifications according to the clinical consequences (clinical outcome) of errors. The consequences of these models are investigated by calculation of the functions of transformation of bias into imprecision according to the assumptions and model calculations. As expected, the functions turn out to be rather different with considerable consequences for these types of transformations. It is concluded that there are at least three models for combining systematic and random variation/errors, each created for its own specific purpose, with its own assumptions and resulting in considerably different results. These models should be used according to their purposes.

Algorithms↗
PubMed2001

Patient-derived quality specifications for instruments used in self-monitoring of blood glucose.

BACKGROUND: Instruments for self-monitoring of glucose (SMBG) are increasingly used by diabetic patients. Information is limited on how patients use and interpret SMBG results, and no quality specifications for such instruments are based on the opinions of patients. METHODS: Type 1 diabetic patients (n = 201) filled in a questionnaire eliciting daily limits for blood glucose (BG) and changes of BG considered significant at different glucose concentrations. From these responses, patient-derived quality specifications were calculated in different clinical situations with low, intermediate, and high BG concentrations. RESULTS: Mean age of the patients was 31.8 years, mean diabetes duration was 14.7 years, and mean SMBG duration was 10.0 years with a mean frequency of 11.2 measurements/week. The threshold for hypoglycemic symptoms was 3.0 mmol/L (54 mg/dL), and the mean daily BG target window was 4.3-10.4 mmol/L (77-187 mg/dL). The mean absolute BG changes producing actions from the patients ranged from 1.1 mmol/L (20 mg/dL) to 3.6 mmol/L (65 mg/dL). The analytical quality specifications for imprecision depended on the clinical situation. Excluding the hypoglycemic situation, the analytical CV needed to fulfill the expectations of 75% of the patients was 6.4-9.7%. The analytical quality specification for CV at hypoglycemic concentrations was 3.1%. CONCLUSIONS: Instruments for self-measurements of glucose with an imprecision (CV) of < or = 5% and bias < or = 5% meet the expectations of >75% of patients in clinical situations other than hypoglycemia.

Adolescent↗
PubMed2001

Do high-threat life events really provoke the onset of psychiatric disorder in children?

Studies on adults have suggested important effects of stressful life events in provoking onset of psychiatric disorder. Only a few comparable studies on children exist, and their results are inconsistent in relation to definite timing effects. Meeting some important methodological challenges overlooked in the past research, this study set out to examine whether the onset of psychiatric disorder in children was more likely to occur shortly after a severe event, as compared with other times. The sample consisted of 99 consecutive, newly referred patients, aged 8-16 years, from a child psychiatry service in London. PACE (Psychosocial Assessment of Childhood Experiences), an investigator-based, standardized interview was used to assess the timing and impact of life events over the preceding 18 months. CAPA (Child and Adolescent Psychiatric Assessment), a standardized diagnostic assessment, was used to establish the presence, timing, and consequential impairment of child and adolescent psychiatric symptoms. In a within-subject, over-time design, conditional logistic regression techniques were employed to examine whether risk of onset was greater in the 9 weeks following a high-threat life event than at other times. There was a small but statistically significant association between child-reported events and child-reported onset; the associations with parent-reported onset were inconsistent. Parent-reported events failed to relate to onset by either source. The study offers only quite limited support to the notion of negative life events provoking onset of psychiatric disorder in children and young people. The possible reasons for this are discussed, together with important conceptual and methodological issues to problems of defining onset, and the choice of appropriate designs for data analysis.

Adolescent↗
PubMed2001

Interpretation of hemoglobin A(1c) (HbA(1c)) values among diabetic patients: implications for quality specifications for HbA(1c).

BACKGROUND: Few studies have examined patients' views, knowledge, and understanding of glycohemoglobin A(1c) (HbA(1c)) testing. We explored such issues in patients with type 1 diabetes and used their statements to estimate analytical quality specifications for HbA(1c) testing. METHODS: We recruited 201 patients from a hospital outpatient clinic. A questionnaire was used to collect information on diabetes characteristics, perceived knowledge of HbA(1c), last HbA(1c) value, HbA(1c) target value, and thresholds for action. Patients were asked to indicate the magnitude of change in HbA(1c) from 9.4% that they would consider to be a true (real) change; from their responses, we calculated patient-derived quality specifications for HbA(1c). RESULTS: Fifty-eight percent of the patients felt they had "high" knowledge about HbA(1c), and >80% of responders knew their last HbA(1c) value, their target HbA(1c), and the threshold value of HbA(1c) for treatment intensification. The mean acceptable HbA(1c) value was 7.5%. Patients with lower values on their most recent tests reported lower target values for HbA(1c) and lower values for the upper HbA(1c) threshold for treatment intensification. An analytical CV (CV(a)) of 3.1% would be satisfactory for 75% of patients when HbA(1c) is increasing (80% confidence), and a CV(a) of 3.2% would be satisfactory for 75% when HbA(1c) is decreasing (95% confidence). CONCLUSIONS: Type 1 patients' perceived knowledge about HbA(1c) testing is high. They are well informed about their own personal results and about target values and the upper HbA(1c) threshold for action. The patient-derived analytical quality specification for imprecision (CV) is 3.1%.

Adolescent↗
PubMed2000

[Guidelines for diagnosis and treatment of sore throat].

BACKGROUND: Available guidelines for the diagnosis and treatment of sore throat give conflicting recommendations. Our aim was to develop evidence-based guidelines. MATERIAL AND METHODS: We searched The Cochrane Library, Medline and other sources for systematic reviews and other evidence that met explicit inclusion criteria for all of the relevant options and outcomes we identified. The validity of included studies was assessed. Draft recommendations based on assessment of this evidence were widely circulated and discussed in focus groups with patients and physician assistants. RESULTS: Throat infections are self-limiting and complications rare. Penicillin shortens the duration of symptoms in tonsillitis caused by beta-haemolytic streptococci and reduces the risk of complications. Penicillin has adverse effects and increases the risk of reinfections. Patients with sore throat should usually be treated without antibiotics. Visiting a physician is normally unnecessary. Antibiotics should be considered in serious cases or if the patient prefers this, but should only be prescribed for throat infections caused by beta-haemolytic streptococci. The diagnosis should be based on clinical criteria and a rapid antigen test in cases of doubt. INTERPRETATION: Benefits of antibiotics must be weighed against harms. Patients should be given good information and involved in decision/making if they want antibiotics.

Anti-Bacterial Agents↗