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PubMed2003

Blood pressure nomograms for school children in Iran.

Currently there are no blood pressure (BP) nomograms based on local data available in Iran. In order to obtain data on BP distribution in Iranian school children, 8848 children aged 7-12 years were studied in Tehran. BP was found to increase with age. Both systolic and diastolic BP showed a positive correlation with height and weight in both sexes. The systolic and diastolic BP in boys and girls were not significantly different. As the sample was representative of Iranian school children, reference standard curves were constructed by modeling data using fractional polynomial. The 50th and 95th percentiles of systolic and diastolic BP of Iranian children were compared for each age with the results reported in the study of the Second Task Force. These percentiles were different from the Second Task Force study. Environmental and genetic determinants are likely to be responsible for the differences. The differences show that the use of local BP nomograms is necessary for assessing the BP levels in Iranian children.

Aging↗
PubMed1994

A nomogram to predict exercise capacity from a specific activity questionnaire and clinical data.

Recent investigations suggested that clinical exercise testing can be optimized by individualizing the protocol, depending on the purpose of the test and the subject tested. This requires some knowledge of a patient's exercise capacity before beginning the test. The accuracy of a simple physical activity questionnaire and readily available clinical data in predicting subsequent treadmill performance was examined. A brief, self-administered questionnaire (VSAQ) was developed for veterans who were referred to exercise testing for clinical reasons. The VSAQ was designed to determine which specific daily activities were associated with symptoms of cardiovascular disease (fatigue, chest pain and shortness of breath). Two hundred twelve consecutive patients (mean age 62 +/- 8 years) referred for maximal exercise testing were studied. Clinical and demographic variables were added to VSAQ responses in a stepwise regression model to determine their ability to predict treadmill performance. Only metabolic equivalents by VSAQ, and age were significant predictors of treadmill performance; these 2 variables yielded R = 0.82 (SEE 1.43; p < 0.001), and explained 67% of the variance in exercise capacity. The regression equation reflecting the relation between age, VSAQ and exercise capacity was: achieved metabolic equivalents = 4.7 + 0.97 (VSAQ) - 0.06 (age). Using this equation, a nomogram was developed. Incorporating the VSAQ with the nomogram requires only a few minutes, and yields a reasonably accurate estimate of a patient's exercise capacity. Although the present equation is population-specific, a similar approach in different populations may be useful for individualizing protocols for clinical exercise testing.

Activities of Daily Living↗
PubMed1994

Steady state feedback in mammalian phototransduction illustrated by a nomogram.

Published data characterizing the four reactions responsible for the Ca(2+)-mediated negative feedback in mammalian rod phototransduction were used to generate graphs which are combined in a circular fashion so that the y-axis of one serves as the x-axis of the next. The nomogram thus created makes it possible to determine by inspection the steady state situation in darkness, and the quasi-steady state situations that pertain shortly after exposure to light of different intensities. The results predicted by the nomogram suggest that Ca(2+)-mediated negative feedback is responsible for the Weber-Fechner relationship between stimulus and response.

1-Methyl-3-isobutylxanthine↗
PubMed1986

A 192Ir nomogram system for single plane implants.

Nomograms for square planar arrays spanning the range from 3 X 3 cm to 10 X 10 cm were developed. The nomograms are intended to be used for pretreatment planning of implant geometry, so that the therapist may enter the operating room with a plan for the optimal implant in mind. We show that clinically useful implants are those in which the reference isodoses are fully coupled. Decoupling occurs when ribbon spacing exceeds approximately 1.2 cm and leads to undesirable "cold spots" within the treatment volume. Ribbon spacing of 1.0 cm is recommended. This represents a trade-off between adequate ribbon coupling and minimum tissue damage from trocar placement. For clinically useful arrays, the area enclosed by the reference isodose contour (85% of the maximum dose rate) is approximately 50% of the array area. Reference isodose contour and its enclosed area are independent of seed strength for a given array, as long as all seeds within the array are of equal strength.

Brachytherapy↗
PubMed2004

Prostate seed implantation using 3D-computer assisted intraoperative planning vs. a standard look-up nomogram: Improved target conformality with reduction in urethral and rectal wall dose.

PURPOSE: To compare dosimetric outcomes between two real-time prostate seed implantation (PSI) techniques to evaluate the impact of three-dimensional (3D) intraoperative computer planning on target coverage, conformality, and preset urethral and rectal dose constraints. METHODS AND MATERIALS: One hundred and fourteen patients with clinically localized prostate cancer underwent ultrasound-guided transperineal PSI of the prostate with (125)I sources as monotherapy. From 1999 to 2001, 69 patients were implanted in real-time using a standard look-up nomogram (Group 1: NG-PSI). All patients were implanted with a modified peripheral loading technique in which 75-80% of the calculated total activity was delivered to the gland periphery, with the remaining 20-25% activity placed in the gland interior, to achieve a prescribed dose (PD) of 144 Gy to cover the gland with acceptable homogeneity. No preoperative or intraoperative planning was performed to set dose constraints to the urethra or anterior rectal wall. Dosimetric outcome from this group was compared with 45 patients subsequently implanted after 2001 using an intraoperative 3D computer planning system (Group 2: 3D-PSI). A similar modified peripheral loading technique was used as an option in the planning system. Preoperative dose constraints were placed on the urethra (V150 < 35%), prostate (V100 > 95% of PD; D90: 140-180 Gy), and rectal wall (V110 < 1.5 cc) with real-time dosimetric feedback performed after peripheral loading. Manual dose optimization was performed to determine interior needle position and remaining number and placement of (125)I sources to adhere to urethral and rectal constraints and target coverage goals. Both groups underwent postimplant CT analysis to determine dosimetric outcome with regard toV100(prostate), D90(prostate), V150(urethra), and V110(rectum). Univariate and multivariate analysis was performed to determine variables impacting on dosimetric outcome. RESULTS: Analysis of preimplant and postimplant variables demonstrated no difference in the median preimplant gland volume (33 cc vs. 35 cc; p = 0.31), median mCi/seed strengths (0.4 vs. 0.45 mCi; p = 0.23), median V100 (94% vs. 94%), or median D90 at postimplant Day 30 (165 Gy vs. 160 Gy; p = 0.26) between Groups 1 and 2. However, for Group 2 (3D-PSI) the median total mCi implanted (26 vs. 33 mCi; p < 0.0001) and the median number of seeds implanted (67 vs. 83; p < 0.0001) were reduced substantially. The percent of patients exceeding a D90 > 180 Gy was reduced from 29% in Group 1 to 16% in Group 2 (p = 0.08). A reduction was observed in the percent of patients receiving a D90 < 140 Gy (14% Group 1 vs. 9% Group 2, p = 0.56). The median V150(urethra) for Group 2 was reduced dramatically with 3D-PSI compared with NG-PSI (63% vs. 17%; p < 0.0001). A V150(urethra) > 30% was observed in 88% in Group 1 compared with 29% in Group 2, p < 0.0001. Similarly, the median V110(rectum) for Group 1 was significantly higher than that in Group 2 (1.93 vs. 0.26 cc; p < 0.0001). The percent of patients with V110(rectum) > 1.5 cc in Group 1 and Group 2 was 57% and 13%, respectively (p < 0.0001). CONCLUSIONS: The adoption of 3D computer intraoperative dose planning and optimization for prostate seed implantation resulted in dramatic reductions in urethral and rectal wall doses, while consistently producing excellent target coverage with reduced dose variability above 180 Gy and below 140 Gy, compared with the use of a standard look-up nomogram. Additionally, the reduction in total mCi and number of seeds needed to achieve improved conformality was substantial and may have implications for cost savings.

Analysis of Variance↗
PubMed1998

Relationship between patient variables and plasma clozapine concentrations: a dosing nomogram.

BACKGROUND: Previous work has suggested factors such as gender, smoking behavior, dose, and age affect the amount of drug a patient requires to achieve a desired plasma concentration of clozapine. Plasma clozapine concentrations ranging from 350 to 504 ng/mL in treatment-refractory schizophrenics and schizoaffective patients produce response rates ranging approximately 55-80%. Without the aid of clozapine plasma concentration monitoring, 3-6 months are recommended for a therapeutic clozapine trial. Data suggest that the lag time to response can be reduced by administering a dose that produces a therapeutic clozapine concentration. METHODS: To generate a clozapine dosing nomogram to predict clozapine steady-state plasma concentrations, a cohort of 71 patients was collected via retrospective chart review and/or patient interview. Clozapine steady-state plasma concentrations and demographic variables were obtained. Multiple-linear regression was utilized to examine the relationship between the plasma clozapine concentration and the independent variables. RESULTS: The dosing model that optimally predicted steady-state clozapine plasma concentrations included the variables dose (mg/day), smoking (yes = 0 and no = 1), gender, and a dose-gender interaction variable. The model explained 47% of the variance in the clozapine concentrations (F = 14.42, p < .001, r2 = .47). Two equations, one for male subjects, i.e., clozapine (ng/mL) = 111 (smoke) + 0.464 (dose) + 145, and one for female subjects, i.e., clozapine (ng/mL) = 111 (smoke) + 1.590 (dose)-149, were derived to predict clozapine steady-state plasma concentrations to serve as a clozapine dosing guide for clinicians. CONCLUSIONS: A clozapine dosing nomogram was constructed as a clinical aid to facilitate clozapine dosing.

Adult↗
PubMed1999

Likelihood ratios and Fagan's nomogram: valuable but underrated tools for in vitro latex sensitization assessment.

The relevance of latex allergy has greatly increased in the last decade especially in health workers and in children with spina bifida. Serological testing has been proposed in the diagnosis since history can be inconclusive and skin and provocative testing can induce severe adverse reactions. We evaluated positive likelihood ratios (LRpos) and the Fagan's nomogram in the diagnosis of latex allergy. Thirty patients with positive clinical history, who showed positive results in the skin prick test and in glove-exposure test were compared to 36 blood donors with negative clinical history, who showed negative results in the skin prick test and in glove-exposure test. LRpos was calculated at four different cutoff concentrations of IgE specific to latex measured with a totally automated analyzer. LRs appear better compared to the traditional classes in the reporting of IgE and, coupled with the Fagan's nomogram which allows the calculation of post-test probability, could improve laboratory testing in latex allergy.

Adult↗
PubMed2002

A nomogram to predict the probability of live birth after clomiphene citrate induction of ovulation in normogonadotropic oligoamenorrheic infertility.

OBJECTIVE: To establish whether initial screening characteristics of normogonadotropic anovulatory infertile women can aid in predicting live birth after induction of ovulation with clomiphene citrate (CC). DESIGN: Prospective longitudinal single-center study. SETTING: Specialist academic fertility unit. PATIENT(S): Two hundred fifty-nine couples with a history of infertility, oligoamenorrhea, and normal follicle-stimulating hormone (FSH) concentrations who have not been previously treated with any ovulation-induction medication. INTERVENTION(S): 50, 100, or 150 mg of oral CC per day, for 5 subsequent days per cycle. MAIN OUTCOME MEASURE(S): Conception leading to live birth after CC administration. RESULT(S): After receiving CC, 98 (38%) women conceived, leading to live birth. The cumulative live birth rate within 12 months was 42% for the total study population and 56% for the ovulatory women who had received CC. Factors predicting the chances for live birth included free androgen index (testosterone/sex hormone-binding globulin ratio), body mass index, cycle history (oligomenorrhea versus amenorrhea), and the woman's age. CONCLUSION(S): It is possible to predict the individual chances of live birth after CC administration using two distinct prediction models combined in a nomogram. Applying this nomogram in the clinic may be a step forward in optimizing the decision-making process in the treatment of normogonadotropic anovulatory infertility. Alternative first line of treatment options could be considered for some women who have limited chances for success.

Abortion, Spontaneous↗
PubMed2002

The renal length nomogram: multivariable approach.

PURPOSE: We built a multivariate renal length nomogram based on ultrasound measurements in pediatric patients with normal renal anatomy. MATERIALS AND METHODS: Included in the study were 707 children 1 week to 18 years old without vesicoureteral reflux, urinary obstruction or other known anatomical anomalies. Renal length was compared among subgroups of children. Multivariate regression approach was used to model renal length, incorporating important demographic variables. RESULTS: Subgroup comparisons of renal lengths showed diverse patterns of renal length differences in children with various demographic characteristics. In addition to age, factors significant in the multivariate nomogram model of renal length included gender, race, weight and height. CONCLUSIONS: These results show that renal length is not only age dependent, but also significantly correlates with other important demographic variables. Variability in renal length can be better described by multivariate analysis. The multivariate approach provides clinically useful information regarding renal outcomes in individuals. The ability to compare renal length among patient subgroups receiving different interventions adds additional usefulness to this approach.

Adolescent↗
PubMed1980

The flow rate nomogram: II. Clinical correlation.

Using the previously demonstrated statistical relationship between urinary flow rate and bladder volume we tested 53 patients with clinically evident outflow obstruction by uroflowmetry. Of these patients 32 were tested before and after a successful operation for outflow obstruction. In 98 per cent of the maximum flow measurements in obstructed patients the nomogram values were less than minus 2 standard deviations, indicating a clear separation from the normal population. After operative relief of the obstruction repeat uroflowmetry demonstrated all values to be in the normal range. Furthermore, in each patient the peak flow rate value increased an average of 2.7 standard deviations (minimum increase of 1.5 standard deviations). No significant correlation could be demonstrated between the size of the prostatic resection and the degree of urinary flow impairment. The use of a flow rate nomogram appears to differentiate reliably normal from obstructed individuals and also is highly useful in the postoperative followup of urinary outflow obstruction.

Humans↗
PubMed2003

[Comparison of a nurse-directed weight-based heparin nomogram with standard empirical doctor-based heparin dosage].

OBJECTIVE: To assess efficiency of a nurse directed weight-based nomogram (NWN) for heparin dosage without training. STUDY DESIGN: Prospective, comparative, before/after intervention study. PATIENTS AND METHODS: In a university medical intensive care unit, 19 patients receiving unfractionned intravenous heparin, following standard medical prescriptions (SHT), were compared to 19 patients submitted to NWN (80 U kg(-1) bolus, starting infusion at 18 U kg(-1) h(-1) and secondary dosage adaptations following a specific nomogram). RESULTS: Dose of heparin bolus and starting dose infusion were significantly greater in NWN group than in the SHT group. The delay in achieving a predetermined therapeutic APTT level of at least 60 s was 6 (1-76) hours in the SHT group and 4 (3- 32) hours in the NWN group. The target APTT (60-85 s) was obtained after 13.5 (1-76) hours and 9.5 (3-32) hours in the two groups, respectively. Although reduction in delay seemed to favour anticoagulation dictated by the NWN protocol, the difference failed to reach statistical significance. Percentage of target APTT over total number of APTT values per patient was significantly higher in the NWN group (41 [0-87] vs. 31% [0-54]) in the SHT group. Strict observance of anticoagulation by using NWN tended to be better than that in SHT group. CONCLUSIONS: NWN protocol was easy to use without previous training. NWN was associated with the best anticoagulation state although its superiority was less evident than expected.

Aged↗
PubMed1996

A nomogram to predict the best biological half-life values for candidates for oral prolonged-release formulations.

It is sometimes possible to maintain plasma concentrations between desired maximum and minimum limits by repetitively administering a drug in an oral prolonged-release formulation when this goal cannot be achieved with a rapid-release formulation. However, this approach does not work with all drugs. The biological half-life value of the drug can be one cause for failure of this approach. Although it is recognized that a half-life may be too long or too short, neither the criteria for determining these values nor the consequences of failing to meet them have been established. The best half-life values for prolonged-release candidates were found by simulating once-a-day and twice-a-day administration of formulations and examining the capacity of these formulations to maintain steady-state plasma concentrations between various selected limits. These observations were used to establish criteria to judge the acceptability of half-lives. Half-life values were considered too long if drugs were self-sustaining and simulations of their rapid-release formulations were also successful. Half-life values were considered too short if minor variability in prolonged-release rates resulted in plasma concentrations above and/or below the selected limits. The actual half-life values that were considered too long or too short depended on the dosing interval and the selected maximum and minimum plasma concentrations. A nomogram was constructed to assess the acceptability of the biological half-life of a candidate for once-a-day or twice-a-day prolonged-release formulations. The nomogram employs the user-selected limits for the desired plasma concentrations to predict whether the half-life of a candidate is (1) too long, (2) too short, or (3) acceptable (i.e., between 1 and 2).

Administration, Oral↗
PubMed2001

Nomogram of Wharton's jelly as depicted in the sonographic cross section of the umbilical cord.

OBJECTIVES: To generate a nomogram for the sonographic measurement of Wharton's jelly area (WJA) during gestation and to investigate whether WJA is related to fetal biometric parameters. METHOD: The sonographic cross-sectional area of the umbilical cord and of its vessels was measured in 659 fetuses between 15 and 42 weeks of gestation. The WJA was calculated by subtracting the vascular area from the umbilical cord area. The conventional biometric parameters were measured and correlated with the WJA. Polynomial regression analysis was utilized for statistical purposes. RESULTS: The WJA increased as a function of gestational age (r = 0.63, P < 0.001). The regression equation for the mean WJA (y) according to gestational age (x) was y = -114.7 + 4.142x - 0.01x2 and for the standard deviation (y') was y' = -7.567 + 1.319x. There was a strong correlation between the WJA and the umbilical cord area (r = 0.97, P < 0.001). A significant correlation was also found between the WJA and fetal biometric parameters before 32 weeks of gestation (WJA and biparietal diameter: r = 0.82, P < 0.001; WJA and abdominal circumference: r = 0.79, P < 0.001; WJA and femur length: r = 0.81, P < 0.001) while after 32 weeks of gestation no correlations were found between WJA and fetal anthropometric parameters. CONCLUSION: A nomogram for the WJA has been generated. The WJA increases as a function of gestational age and it is correlated with fetal size up to 32 weeks of gestation.

Adult↗
PubMedDate not supplied

Plasma volume nomograms for use in therapeutic plasma exchange.

Nomograms have been developed for the convenient estimation of the plasma volumes of patients undergoing therapeutic plasma exchange (TPE), based on equations employing height, body weight, and hematocrit. These nomograms are offered as an aid to prescribing continuous-flow TPE procedure exchange volumes.

Humans↗
PubMed1982

[Nomogram for determining the refraction of intraocular lenses].

A nomogram for determining the refraction of intraocular lenses was developed to define the following diagnoses: emmetropizing lens, residual refraction of a given lens refraction and desired postoperative refraction. The nomogram makes an approximation solution possible to determine the refractive power of intraocular lenses from the basic refraction and the refractive power of the cornea.

Humans↗
PubMed1976

The construction and use of nomograms for cerebral blood flow calculation using a 133Xe inhalation technique.

Measurement of cerebral blood flow (CBF) using a 133Xe inhalation technique requires monitoring the clearance rate of the radioisotope from the head using externally situated detectors and also from arterial blood using a detector to monitor the expired air activity. The end-tidal concentration function is assumed to be proportional to the arterial concentration function and this has to be deconvoluted from the clearance functions obtained from the head to enable CBF to be calculated. A digital computer is generally considered to be essential for this. In this paper a procedure using three-dimensional nomograms is derived and tested. It is shown that results obtained using the nomograms do not differ significantly from results obtained using a full deconvolution procedure, and so it is not essential to use a computer to calculate CBF by the inhalation technique.

Cerebrovascular Circulation↗
PubMed1981

Nutrient-cost nomogram: an appropriate technology.

The nutrient-cost concept is important in food and nutrition planning and applied nutrition programs. There is a need to develop a simple and quick method of calculating nutrient-cost values. A nomogram, which provides a new technology, has been devised to do this. The use of the nomogram and its theoretical basis are described.

Cost-Benefit Analysis↗