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PubMed1989

Body surface related flow rate nomograms in a normal pediatric population.

Uroflow studies for 511 normal pediatric subjects (272 boys, 239 girls) were analyzed statistically. Nomograms relating peak flow to volume voided and body surface were established. An acceptable lower limit for peak flow was obtained from the data and a volume voided range was calculated so that both criteria could be used with 90% probability to define the normal voiding situation. Body surface area was found to be a more reliable index than age in the establishment of nomograms. In the male population the 90% probability applied to a significantly greater volume voided reliability. In the female population mean peak flow rate rose with increased body surface. Finally, in both sexes the 10% lower limit was closer to the regression mean, allowing a tighter distribution around this value.

Adolescent↗
PubMed1988

Estimation of nongravid uterine volume based on a nomogram of gravid uterine volume: its value in gynecologic uterine abnormalities.

To facilitate accurate and standard methods of reporting pathologic uterine corpus enlargement, we constructed a nomogram using the gravid uterine corpus volumes from five to 20 weeks' gestation in 186 patients. The volume was calculated by measuring the maximum length and anteroposterior and transverse diameters of the uterine corpus, and using the formula for the volume of a prolate ellipsoid: V = 0.52 X (L X AP X T). Clinicians can use the nomogram for better understanding in assessing uterine volume.

Female↗
PubMed1987

Accuracy of Bayesian, Sawchuk-Zaske, and nomogram dosing methods for vancomycin.

The predictive performance of a Bayesian method for vancomycin dosing was compared with that of two nomogram-based methods and the Sawchuk-Zaske method. Prospectively collected serum concentration data were evaluated retrospectively in patients who had at least two steady-state peak and trough serum vancomycin concentrations obtained during two different dosage regimens. The methods evaluated were a Bayesian program that uses a one-compartment weighted-sum-of-squares expression; the nomogram methods of Moellering and Matzke, which derive vancomycin clearance from urinary creatinine clearance; and the Sawchuk-Zaske method, which uses equations for one-compartment, first-order elimination. The ability of each method to predict the second set of serum concentrations when given the first set of concentrations was evaluated using mean prediction error (ME), mean absolute error (MAE), and root mean squared error (RMSE). To compare the predictions made by each of the four methods, the differences in mean error and the differences in the natural logarithm of mean absolute error and their 95% confidence intervals were compared. No significant difference in ME (bias) or MAE (precision) was found between the Moellering and Matzke methods. The Sawchuk-Zaske method was significantly more precise than the Matzke method in predicting peak serum concentrations and more precise than the Moellering or Matzke method in predicting trough concentrations. The Bayesian program was significantly more precise and less biased than the Moellering and Matzke methods and less biased than the Sawchuk-Zaske method in predicting both peak and trough concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

[Nomograms for calculating the parameters of a system of recording intracavitary pressure through sounds].

The signal of the intracavitary pressure registered through a probe is, as a rule, distorted by fluctuations of the liquid column in the probe. Nomograms enabling the velocity of the sound wave and the own frequency oscillations of the measuring system to be found from the size of the probe, elastic modulus of its material and elasticity of the bulk of the guage are described. In this way a selection of probes to secure high-quality recording of the signal is facilitated. An example of a calculation with the use of the nomograms is given.

Blood Pressure Determination↗
PubMed1981

Transfusion nomogram: an application of physiology to clinical decisions regarding the use of blood.

A nomogram has been prepared that depicts relationships between cardiac output (Q), oxygen consumption (Vo2), hemoglobin concentration (Hb), the position of the oxygen-hemoglobin dissociation curve, the oxygen saturation of arterial blood (SaO2), and the partial pressure of oxygen in the mixed venous blood (PVO2). Examples are provided to illustrate how this nomogram may be employed to facilitate decisions regarding the need for blood transfusions in patients in whom oxygen delivery may be impaired.

Blood Transfusion↗
PubMed1981

Development and critical evaluation of the food nomogram.

The historical development and validation of the Food Nomogram is described to show the scientific basis of formulas to predict caloric need. Prediction of basal caloric need in nutritional assessment using formulas such as that represented by the Mayo Foundation Nomogram is based on surface area and standardized kilocalories per unit of surface area. Though these quantities do reflect error, major discrepancies evolve with prediction of total need, including kilocalories for activity. In spite of these limitations, predicting formulas have been valuable tools in predicting total caloric need. Three formulas are contrasted and found reliable.

Adolescent↗
PubMedDate not supplied

[Estimation of intrapulmonary shunt in resuscitation (use of a nomogram) (author's transl)].

Acutely ill patients often show rapid and sometimes concomitant changes in haemodynamics, pulmonary exchange and O2-uptake. PaO2 reflects the interrelationships between these three factors. The Qs/Qt shunt is computed by taking two simultaneous blood samples, one systemic arterial, the other mixed venous, with the patient inhaling pure O2 for twenty minutes. In estimating the fraction of total cardiac output unsaturated in pulmonary transit, Qs/Qt is practically used as a selective test for pulmonary gas exchange. We propose a nomogram, showing in terms of Qs/Qt shunt the variations of PaO2, of haemoglobin O2 saturation and of arterial-venous difference of O2 concentrations. Blood gas changes during treatment of shock or of acute respiratory insufficiency are explained by use of this nomogram.

Carbon Dioxide↗
PubMed1993

Nomogram for Doppler echocardiographic assessment of mitral stenosis in atrial fibrillation.

Non-invasive assessment of the stenotic mitral valve area is often difficult when the mitral stenosis is associated with atrial fibrillation. In this study, 16 patients with mitral stenosis and atrial fibrillation were evaluated by transthoracic Doppler echocardiography. The mitral valve area calculated by the pressure half-time method was 1.65 +/- 0.73 cm2. The enddiastolic mitral gradient was obtained from the enddiastolic forward mitral flow velocity by application of the simplified Bernoulli equation. For each patient there was a linear relationship between the enddiastolic mitral gradient and the corresponding RR interval. The slope and intercept of this relationship were significantly correlated with the mitral valve area. From the regression equations describing these correlations we established a nomogram ascertaining mitral valve area from enddiastolic mitral gradient and corresponding heart rate. This nomogram was helpful in the non-invasive assessment of stenotic mitral valve area in the presence of atrial fibrillation.

Aged↗
PubMed1994

A graphical nomogram method for predicting toxic concentrations of unbound phenytoin.

The graphical nomogram method to estimate the phenytoin free concentration at any selected total serum phenytoin and/or albumin concentrations was applied using Scatchard binding equation. The binding parameters were calculated by the non-linear least-squares regression analysis of the binding data collected from 96 outpatients on common anticonvulsant therapy. Free phenytoin concentration was measured by the Amicon multi-micro ultrafiltration system. The mean values of N and Kapp were found to be: N = 1.03, and Kapp = 18,500 (M-1). Correlation coefficient for relationship between measured and predicted free phenytoin concentrations was very good (r = 0.94), but the results of prediction-error analysis (MPE = 0.153, and RMSE = 0.296) show that the nomogram method overpredicts the measured free phenytoin (PHT) concentration approximately about 10% higher (15-30 mg/l) than serum phenytoin levels.

Adult↗
PubMed1976

Acid-base balance nomogram--a Boston-Copenhagen detente.

Quantitation of actual and expected complete compensation for chronic hypercapnia in man is facilitated by addition of data of Brackett et al. in the form of an arc to the Siggaard-Andersen alignment nomogram. Percentage of compensation is defined as 100 times the ratio of observed to predicted (fully compensated) base excess at the patient's PCO2. Extracellular fluid base excess, defined as BE3, is estimated from a 3-g hemoglobin line added to the nomogram.

Acid-Base Equilibrium↗
PubMed2007

Nomograms of the axial fetal cerebellar hemisphere circumference and area throughout gestation.

OBJECTIVE: The widely applied transcerebellar diameter (TCD) obtained at axial cranial imaging, measures the distance between the lateral aspects of the cerebellum and incorporates the width of the cerebellar vermis. Our objective was to create reference ranges of axial fetal cerebellar hemisphere circumference (CHC) and area (CHA), independent of the cerebellar vermis, throughout gestation. METHODS: This cross-sectional study involved pregnant patients between 14 and 41 weeks of gestation. Inclusion criteria consisted of well-established dates (confirmed by early ultrasound), non-anomalous singleton fetuses and intact amniotic membranes. Sonographic measurements included biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), femur length (FL), humerus length (HL), TCD, and estimated fetal weight (EFW). Values of axial fetal CHC and CHA were each calculated as the mean of three separate measurements. The 5th, 50th and 95th centiles were estimated at each week of gestational age (GA) by least-squares regression for the mean and standard deviation (SD) of the CHC and CHA as functions of GA. r2 and associated P-values for the relationships of CHC and CHA with other sonographic biometric measurements were calculated. RESULTS: The study included 651 consecutive patients. All attempts at obtaining axial fetal CHC and CHA were successful. Mean maternal age was 27.3+/-6.7 years, median gravidity was 1 (range 1-16), and median parity was 1 (range 0-6). Mean CHC (cm) throughout gestation was modeled as -2.091+0.2563xGA (weeks) (SD=-0.075+0.0164xGA), and mean CHA (cm2) was modeled as 0.245-0.0765xGA+0.00506xGA2 (SD=1.167-0.1565xGA+0.006785xGA(2)-0.00008028xGA3). Fetal axial CHC and CHA correlated significantly and strongly with BPD, HC, AC, HL, FL, TCD and EFW (all R2 values were >or=0.95, and all P-values were <0.001). CONCLUSION: Nomograms of axial fetal cerebellar hemisphere circumference and area throughout gestation, independent of the cerebellar vermis, have been provided.

Abdomen↗
PubMed2004

Patient, surgeon, and treatment characteristics associated with homologous blood transfusion requirement during radical retropubic prostatectomy: multivariate nomogram to assist patient counseling.

OBJECTIVES: To identify the preoperative patient, treatment, and surgeon factors associated with the administration of homologous blood transfusion during or after radical retropubic prostatectomy (RRP) to be able to better inform patients regarding the probability of transfusion. Homologous blood transfusion is sometimes required during or after RRP, but predictive models for estimating transfusion probability using patient and surgical characteristics are lacking. METHODS: Data were prospectively collected regarding patient characteristics, cancer severity, surgeon experience, anesthetic used, operative blood loss, and transfusion among 1123 consecutive RRP cases. Multivariate regression analysis identified baseline factors associated with a homologous transfusion requirement and generated a model for predicting the likelihood of perioperative homologous transfusion. RESULTS: Homologous transfusion was administered in 3.8% of subjects; the mean estimated blood loss was 953 mL. Multivariable regression analysis identified prostate size (P <0.0001, odds ratio [OR] 1.74), use of general anesthesia (P = 0.01, OR 2.22), use of neoadjuvant hormonal therapy (P = 0.006, OR 3.35), and surgeon expertise (P <0.0001, OR 8.63) as independent risk factors associated with a need for perioperative homologous transfusion. The most influential factor, surgical expertise, clustered among surgeons who performed more than 15 RRPs annually, because these surgeons had lower transfusion rates and lower estimated blood loss more consistently than did surgeons who performed fewer RRPs annually. CONCLUSIONS: Larger prostate size, use of general anesthesia, use of neoadjuvant hormonal therapy, and annual surgeon case volume were independently associated with an increased probability that an individual patient would receive homologous transfusion during or after RRP. A nomogram indicating the probability of homologous transfusion based on these factors provides a benchmark of expected homologous transfusion rates according to individual patient and treatment parameters.

Adenocarcinoma↗
PubMed2006

Using prostate-specific antigen screening and nomograms to assess risk and predict outcomes in the management of prostate cancer.

We review the role of prostate-specific antigen (PSA) and the importance of patient education in the management of prostate cancer, based on discussions held at a European symposium on managing prostate cancer. Although PSA is the most widely used serum marker for detecting prostate cancer and for monitoring treatment responses, its use as a diagnostic marker is controversial due to concerns of over-diagnosis and low specificity. PSA isoforms, as well as PSA doubling time, might improve the specificity for earlier prostate cancer detection and can be used as surrogate markers for treatment efficacy. Patients can differ considerably in the importance they place on health-related quality of life aspects and fear of cancer progression. Consequently, there needs to be active, educated discussion of risk and outcomes between physicians and patients. Risk assessment tools, e.g. validated nomograms, enable clinicians to improve their decision analysis and form the basis for subsequent discussion of treatment options between the physician and patient, thereby enabling informed consent and appropriate decision-making.

Humans↗
PubMed2006

How many oxygen cylinders do you need to take on transport? A nomogram for cylinder size and duration.

When undertaking patient retrieval, it is important to take adequate supplies of oxygen to ensure patient safety. Oxygen can be delivered via a flowmeter into a facemask or used to drive pneumatic ventilators. Given the lack of space in the back of an ambulance or helicopter, the numbers of cylinders that can be taken is limited, hence the number needed to complete the journey must be carefully calculated prior to embarking. We have produced nomograms to predict how many oxygen cylinders will be consumed during a given journey when using either a flowmeter or a commonly used transport ventilator.

Equipment Design↗
PubMed2006

Finite-element modeling of posterior lamellar keratoplasty: construction of theoretical nomograms for induced refractive errors.

PURPOSE: To estimate the theoretical corneal refractive error induced by mechanical weakening effects from posterior lamellar keratoplasty (PLKP) in the human cornea. METHODS: The refractive effects of PLKP are simulated by finite-element modeling (FEM) as a mathematical function of the thickness of the excised posterior lamellar corneal button, with a nonlinear formulation of stress-strain relation for the corneal material. A theoretical nomogram was developed to correlate the refractive changes to button thickness. RESULTS: The predicted refractive change after PLKP is less than 1 dpt for a 170-microm thickness posterior corneal button over a broad range of Young's modulus. Thicker buttons result in greater surgically induced refractive errors. CONCLUSIONS: According to FEM analysis, the excision of a posterior lamellar button of less than 170 microm thickness produces a minimal predicted refractive change (< 1 dpt) in the cornea after PLKP.

Biomechanical Phenomena↗