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At least 505 records · Page 28Linked to original sources
PubMed2004

The three-vessel and tracheal view of the fetal heart: an in utero sonographic evaluation.

OBJECTIVES: To establish a nomogram for fetal cardiac three-vessel view diameter changes during gestation. METHODS: The study is a prospective cross-sectional evaluation of 338 male and female fetuses between 14 and 38 weeks of normal singleton pregnancies. Measurements of fetal pulmonary artery, aorta and superior vena cava diameters, performed on a transverse view of the upper mediastinum were conducted using transvaginal ultrasonography between 14 to 18 weeks and transabdominal after 19 weeks' gestation. RESULTS: Adequate measurements of the three cardiac vessels were obtained in 338 fetuses. The regression equations for vessel diameters modeled as function of gestational age were pulmonary artery diameter (mm) = -2.275 + 0.273 x gestational age (week), aorta diameter (mm) = -1.77 + 0.227 x gestational age (week), and SVC diameter (mm) = -0.98 + 0.142 x gestational age (week). The correlation coefficients between gestational age and the diameter of the vessels were, r = 0.93, r = 0.93 and r = 0.86 for pulmonary artery, aorta and SVC respectively (all found to be highly statistically significant, p < 0.0001). The normal mean and 90% prediction limits were defined. CONCLUSION: Our data present the normal range of fetal heart three-vessel diameters during gestation. They may allow intrauterine assessment of their development and an adjunct in the detection and evaluation of great vessel pathology.

Aorta↗
PubMed1994

Infrarenal aortic diameter in the healthy person.

In order to determine the relevance of abdominal aortic dilatation, knowledge of the normal aortic diameter and its relation to age, sex and body size (height, weight, body surface area) is essential. The diameter of the infrarenal aorta was measured in 146 healthy males and females 4-74 years old with ultrasonography and the influence of the aforesaid factors on aortic diameter was analysed by means of a multiple stepwise regression model. The infrarenal aorta was found to increase steadily in diameter throughout life. From about 25 years the diameter was larger in males than in females (p < 0.01) though this difference vanished if corrected for differences in body surface area. Significant correlations were found between aortic diameter and weight (r = 0.84, p < 0.001), height (r = 0.77, p < 0.001) and body surface area (r = 0.83, p < 0.001). Age followed by body surface area were the factors most influencing aortic diameter in both males (r = 0.92, p < 0.001) and females (r = 0.94, p < 0.001). Nomograms predicting aortic diameters in relation to age, sex, and body surface area are presented.

Adolescent↗
PubMed1987

The efficiency of systematic sampling in stereology and its prediction.

The superior efficiency of systematic sampling at all levels in stereological studies is emphasized and various commonly used ways of implementing it are briefly described. Summarizing recent theoretical and experimental studies a set of very simple estimators of efficiency are presented and illustrated with a variety of biological examples. In particular, a nomogram for predicting the necessary number of points when performing point counting is provided. The very efficient and simple unbiased estimator of the volume of an arbitrary object based on Cavalieri's principle is dealt with in some detail. The efficiency of the systematic fractionating of an object is also illustrated.

Animals↗
PubMed2001

Assessing patients with possible heart disease using scores.

Multivariable analysis of clinical and exercise test data has the potential to become a useful tool for assisting in the diagnosis of coronary artery disease, assessing prognosis, and reducing the cost of evaluating patients with suspected coronary disease. Since general practitioners are functioning as gatekeepers and decide which patients must be referred to the cardiologist, they need to use the basic tools they have available (i.e. history, physical examination and the exercise test), in an optimal fashion. Scores derived from multivariable statistical techniques considering clinical and exercise data have demonstrated superior discriminating power compared with simple classification of the ST response. In addition, by stratifying patients as to probability of disease and prognosis, they provide a management strategy. While computers, as part of information management systems, can run complicated equations and derive these scores, physicians are reluctant to trust them. Thus, these scores have been represented as nomograms or simple additive tables so physicians are comfortable with their application. Their results have also been compared with physician judgment and found to estimate the presence of coronary disease and prognosis as well as expert cardiologists and often better than nonspecialists. However, the discriminating power of specific variables from the medical history and exercise test remains unclear because of inadequate study design and differences in study populations. Should expired gases be substituted for estimated metabolic equivalents (METs)? Should ST/heart rate (HR) index be used instead of putting these measurements separately into the models? Should right-sided chest leads and HR in recovery be considered? There is a need for further evaluation of these routinely obtained variables to improve the accuracy of prediction algorithms especially in women. The portability and reliability of these equations must be demonstrated since access to specialised care must be safe-guarded. Hopefully, sequential assessment of the clinical and exercise test data and application of the newer generation of multivariable equations can empower the clinician to assure the cardiac patient access to appropriate and cost-effective cardiological care.

Adult↗
PubMed1998

Prediction of maximal aerobic power in healthy Indian males 21-58 years of age.

An attempt has been made in this paper to predict maximal aerobic power (VO2max) in healthy Indian males by three important physical characteristics (viz. age, height and body weight) using the technique of multivariate regression analysis for a wide age group ranging from 21 to 58 years. It has been observed that these characteristics can contribute significantly to the prediction of maximal aerobic power. Three combinations of predictors of two predictors at a time have also been tried to predict maximal aerobic power. Out of these three combinations, the combination of age and body weight has the maximum multiple correlation (R = 0.536, P < 0.001) for a group of 146 subjects of healthy Indian males. A nomogram has been constructed to predict VO2max from age and body weight in order to make the developed multiple linear regression equation of more practical utility to the biomedical scientists who may not be well acquainted with the statistical computational work.

Adult↗
PubMedDate not supplied

Early transvaginal biometry of fetal orbits: a cross-sectional study.

OBJECTIVE: To construct nomograms of orbital diameters in early pregnancy by transvaginal sonography. DESIGN: A prospective cross-sectional study. METHODS: The study was performed on 923 consecutive normal singleton pregnancies from 10 to 16 weeks of gestation, using transvaginal high-resolution ultrasound technique. The interocular distance (IOD), binocular distance (BOD), as well as the orbital diameter (OD) at each gestational age (GA, days), were recorded. The distribution of the residuals for the different orbital measurements are also described. RESULTS: The increase in each of the ocular parameters studied could be accurately described by a linear model. The regression equation for orbital measurements as a function of GA was: for IOD, y = 0.153 GA (days) - 6.73 (r2 = 0.82); for BOD, y = 0.387 GA (days) - 16.85 (r2 = 0.80), and for OD, y = 0.132 GA (days) - 6.435 (r2 = 0.79). IOD and OD demonstrate a normal distribution of the residuals with uniform variance. CONCLUSION: The presented data obtained in early pregnancy by transvaginal scan offer normative measurements of the orbital diameter which may be useful in the prenatal diagnosis of congenital syndromes that include, among other manifestations, orbit maldevelopment and growth disturbances.

Adult↗
PubMed1984

Construction of acid-base alignment nomograms to estimate buffer base and base-excess concentrations in arterial blood from immature pigs.

Acid-base characteristics of a population of immature domestic pigs were used to construct a blood acid-base alignment nomogram with scales to estimate porcine buffer base concentration. The nomogram was based on average plasma bicarbonate concentration of 31.6 mEq/L and plasma albumin and globulin values of 25.4 and 32.2 g/L, respectively. A measurement temperature of 38 C was assumed. Subsequently, this nomogram was used to construct a blood acid-base alignment nomogram with scales to estimate porcine base-excess concentration. The nomogram was based on the assignment of zero-base excess to blood with a pH of 7.50 and a PCO2 of 40 mm of Hg. Construction details, including tabular data reflecting the acid-base characteristics of porcine plasma and erythrocytes, are provided.

Acid-Base Equilibrium↗
PubMedDate not supplied

Geometric and muscle physiological determinants of cardiac stroke volume as evaluated on the basis of model calculations.

Based on model calculations a mathematical approach has been developed which permits an analysis and approximative evaluation of the significance of geometric and various muscle physiological factors for cardiac stroke volume with respect to anatomical ventricular size. Despite increasing wall stress the stroke volume generally increases with growing anatomical heart size, reaching a maximum beyond which it falls off. On the basis of the model of a thick-walled sphere for the left ventricle, stroke-volume-radius relations have been calculated for three different types of chronic ventricular enlargement (constancy of wall thickness, wall volume, or of the ratio of wall thickness to inner radius) in particular. In all three cases stroke volume increases with chronic enlargement of the heart, at least to a certain extent. Thus, stroke volume can be augmented with increasing anatomical heart size under constant contractile conditions despite decreasing ejection fraction. This fact has to be considered in the assessment of ventricular function. Nomograms are obtained by varying contractility, wall thickness, or end-systolic pressure while keeping the other contractile conditions constant, thus permitting the evaluation of the effect of therapeutic measures in the presence of cardiac dilatation.

Heart↗
PubMedDate not supplied

Better decisions through science: exercise testing scores.

Statistical tools can be used to create scores for assisting in the diagnosis of coronary artery disease and assessing prognosis. General practitioners and internists frequently function as gatekeepers, deciding which patients must be referred to the cardiologist. Therefore, they need to use the basic tools they have available (ie, history, physical examination and the exercise test) in an optimal fashion. Scores derived from multivariable statistical techniques considering clinical and exercise data have demonstrated superior discriminating power compared with diagnosis only using the ST segment response. In addition, by stratifying patients as to probability of disease and prognosis, they provide a more practical management strategy than a response of normal or abnormal. Although computers, as part of information management systems, can calculate complicated equations and derive these scores, physicians are reluctant to trust them. However, when represented as nomograms or simple additive discrete pieces of information, scores are more readily accepted. The scores have been compared with physician judgment and have been found to estimate the presence of coronary disease and prognosis as well as expert cardiologists and often better than nonspecialists. However, the discriminating power of specific variables from the medical history and exercise test remains unclear because of inadequate study design and differences in study populations. Should expired gases be substituted for estimated METs? Should ST/heart rate index be used instead of putting ST depression and heart rate separately into the models? Should right-sided chest leads and heart rate in recovery be considered? There is a need for further evaluation of these easily obtained variables to improve the accuracy of prediction algorithms, especially in women. The portability and reliability of scores must be ensured because access to specialized care must be safeguarded. Assessment of the clinical and exercise test data and application of the newer scores can empower the clinician to assure the cardiac patient access to appropriate and cost-effective cardiologic care.

Age Factors↗
PubMed2001

Elevation of serum interleukin 8 levels in acetaminophen overdose in children and adolescents.

BACKGROUND: Elevations of inflammatory cytokines have been reported in animal models of acetaminophen (INN, paracetamol) toxicity. In addition, interleukin 8, a chemokine, has been found to be elevated in toxin-associated hepatic disease (ie, acute alcoholic hepatitis). The purpose of this study was to measure serum cytokine levels in children and adolescents with acetaminophen overdose and to evaluate relationships between cytokine elevation and hepatotoxicity. METHODS: Serum levels of tumor necrosis factor alpha, interleukin 1beta, interleukin 6, interleukin 8, and interleukin 10 were measured by ELISA in children and adolescents (n = 35) with acetaminophen overdose. Peak cytokine levels were examined relative to biochemical evidence of hepatocellular injury, nomogram risk assessment, and prothrombin time. RESULTS: Five patients had aspartate aminotransferase or alanine aminotransferase levels >1000 IU/L, and 4 patients had aspartate aminotransferase or alanine aminotransferase levels > or =100 IU/L and < or =1000 IU/L. No elevations of tumor necrosis factor alpha or interleukin 1beta were detected. Peak interleukin 8, but not interleukin 6 or interleukin 10, correlated with hepatotoxicity (Mann-Whitney exact test, P <.001). The peak interleukin 8 level was greater in patients at high risk by the nomogram combined with those presenting at >15 hours, as compared with other patients (Mann-Whitney U test, P <.01). The interleukin 8 level peaked before aspartate aminotransferase or alanine aminotransferase in 5 of the 9 patients with hepatotoxicity. In addition, interleukin 8 concentrations of >20 pg/mL were associated with peak prothrombin time values (Mann-Whitney exact test, P <.015). CONCLUSIONS: Interleukin 8 elevation in patients with acetaminophen hepatotoxicity corresponds with other common clinical measures that are predictive of hepatocellular injury. Further study is warranted to evaluate possible mechanistic relationships between inflammatory cytokines and acetaminophen hepatotoxicity in children and adults.

Acetaminophen↗
PubMed1976

Rough determination of the cost-benefit balance point of sanitation programmes.

Resources for sanitation programmes in developing countries are limited and therefore must be used judiciously to obtain the best possible effect. Cost-benefit analysis is a tool that permits the better utilization of available resources. A simple method for rough determination of the cost-benefit balance point has been devised which requires little computation. To reduce the computations to a minimum, nomograms have been constructed which require little or no mathematical skill for their use. While the method falls short of perfection, its simplicity makes it useful for a rough evaluation of the benefits from sanitation programmes aimed at disease control in countries whose resources are not available for more sophisticated analysis.

Communicable Disease Control↗
PubMed2004

New nomogram for foetal weight estimation based on Hadlock's two-parameter formula.

AIM: To develop and validate a graphical method for ultrasonic foetal weight estimation with predictive qualities comparable to state-of-the-art computational methods. METHOD: Study data were obtained from 3839 consecutive singleton pregnancies with ultrasound examination within 7 days of delivery. We translated the well established Hadlock 2-parameter formula based on abdomen circumference and femur length into a nomogram [corrected]. We compared the measured foetal weight with estimations obtained from this new nomogram and three other methods. RESULTS: Measured by the foetal weight percentage error the new nomogram underestimates the foetal weight on average by 2.5 % (9.86) (mean [SD]) with uniform results over the complete birth weight spectrum. By the same measurement the Hadlock 4-parameter formula underestimates the foetal weight by 1.2 % (9.3) whereas the Hansmann nomogram overestimates the foetal weight by 14.5 % (16.1) The difference between the estimated foetal weight percentage error obtained from the new nomogram and from the Hadlock 2-parameter formula is 0.06 % (0.27) and hence clinically irrelevant. CONCLUSION: The new nomogram has predictive qualities comparable to state-of-the-art computational methods and is thus not only as reliable but also easy to use in situations when computers are not available. It can be recommended for foetal weight estimation over the whole spectrum of birth weight.

Embryonic and Fetal Development↗
PubMed2001

Pretreatment nomogram for predicting freedom from recurrence after permanent prostate brachytherapy in prostate cancer.

OBJECTIVES: To develop a prognostic nomogram to predict the freedom from recurrence for patients treated with permanent prostate brachytherapy for localized prostate cancer. METHODS: We performed a retrospective analysis of 920 patients treated with permanent prostate brachytherapy between 1992 and 2000. The clinical parameters included clinical stage, biopsy Gleason sum, pretreatment prostate-specific antigen (PSA) value, and administration of external beam radiation. Patients who received neoadjuvant androgen deprivation therapy were excluded. Failure was defined as any post-treatment administration of androgen deprivation, clinical relapse, or biochemical failure, defined as three PSA rises. Patients with fewer than three PSA rises were censored at the time of the first PSA rise. Data from two outside institutions served as validation. RESULTS: A nomogram that predicts the probability of remaining free from biochemical recurrence for 5 years after brachytherapy without adjuvant hormonal therapy was developed using Cox proportional hazards regression analysis. External validation revealed a concordance index of 0.61 to 0.64, and calibration of the nomogram suggested confidence limits of +5% to -30%. CONCLUSIONS: The pretreatment nomogram we developed may be useful to physicians and patients in estimating the probability of successful treatment 5 years after brachytherapy for clinically localized prostate cancer.

Adenocarcinoma↗
PubMed2001

Fetal transverse cerebellar diameter in Thai population.

We developed a nomogram for transverse cerebellar diameter (TCD) in Thai fetuses by recruitment of 153 normal pregnant women in the first trimester. The gestational age calculated by the certain last menstrual period and the first trimester ultrasound were in agreement. The pregnant women were stratified into 4 groups and scanned at four weekly intervals: group A was first scanned at 14 weeks, group B at 15 weeks, group C at 16 weeks, and group D at 17 weeks. A total of 699 measurements from 14 to 40 weeks of gestation were obtained. The data were analyzed for mean and standard deviation; and the best fit mathematical model was derived. The TCD grew progressively along gestational age. The growth rate was slightly less than that of a Western study after 28 weeks of gestation. This could serve as the basis for gestational dating in fetuses with aberrant fetal growth.

Adolescent↗
PubMedDate not supplied

Redesign of a weight-based heparin protocol for improved outcomes in a community hospital.

Heparin has long been used to minimize complications of a variety of disorders and reaching a therapeutic level within 24 hours has been shown to improve patient outcomes. However, the dosing of heparin to reach a therapeutic level has been controversial. At our institution a weight based heparin nomogram was in place, however an initial data analysis revealed a large percent of the initial aPTT levels were above therapeutic range. This article will describe the performance improvement process and the overall goal to decrease the percentage of patients exceeding the initial therapeutic aPTT levels without compromising daily therapeutic aPTT levels.

Anticoagulants↗
PubMedDate not supplied

Effect of right-to-left shunting on alveolar dead space.

Right-to-left shunting decreases the efficiency of carbon dioxide excretion and increases the alveolar dead space (physiological dead space minus anatomical dead space). The theoretical effects of shunting on alveolar dead space were studied, using a human blood nomogram, for different values of inspired oxygen fraction (FIO2), respiratory quotient (R), and arterial-venous oxygen content difference. An equation developed to define the relationship between alveolar dead space and shunt could be closely fitted to the nomogram data. With high levels of shunt, FIO2 and R, alveolar dead space can substantially increase above normal levels. The conditions needed for this increase are unusual but lie within the range observed in critically ill patients. A rise in dead space of this magnitude can be clinically important in the absence of effective compensatory mechanisms.

Carbon Dioxide↗
PubMed2005

Effect of gestational age and position on peak expiratory flow rate: a longitudinal study.

OBJECTIVE: We sought to study the effects of gestational age and maternal position on peak expiratory flow rates. METHODS: Peak expiratory flow rates were measured in the standing, sitting, and supine positions in 38 healthy pregnant women at 4-week intervals starting at less than 10 weeks until delivery and again at 6 weeks postpartum. The highest reading of 3 consecutive peak expiratory flow rate measurements for each encounter and position was used in the analysis. Repeated measures analysis of covariance was performed with subjects, gestational age, position, and gestational age times position as the model effects. Least squares mean peak expiratory flow rates were compared among positions at different gestation ages using Bonferroni-adjusted least significant difference t tests. RESULTS: Peak expiratory flow rate declined significantly throughout gestation in all positions (P < .001) with mean rate of decline of 0.65 L/min per week). The slopes of linear trends were not statistically different between positions (P = .222). However, the rate of decline for the supine position was higher than for standing and sitting positions (0.86 compared with 0.46 and 0.57 L/min per week), respectively. On average, the postpartum peak expiratory flow rate returned to 71.9% of its measurement in early gestation. Nomograms depicting mean and the 5th and 95th percentiles of peak expiratory flow rates were constructed for each position. CONCLUSION: Peak expiratory flow rate measurements are affected by maternal position and advancing gestational age, especially in the supine position. Adjustment of patient's flow rate in relation to gestational age and maternal position is recommended, especially in pregnant women with asthma. LEVEL OF EVIDENCE: III.

Adult↗
PubMed2006

Outcomes research: a methodologic review.

OBJECTIVES: We explored the history and conceptual trends of outcomes research. METHODS: We described different aspects of this field, after dividing it into conceptually distinct strata. RESULTS: Outcomes research can be divided into macro, meso and micro levels. Each level is further subdivided. Macro-level research targets cost and health care utilization, as well as racial, ethnic and geopolitical population health determinants. Meso-level studies address effectiveness, variability, disease impact, clinical modeling and program evaluation studies. Finally, micro-level studies address all aspects of direct patient-clinician decision-making. CONCLUSIONS: An explosion of outcomes research has occurred in the past decades. Wide access to information technology, data sharing and collaborative efforts between researchers represent some of the ingredients that did and will continue to fuel that growth.

Humans↗