Uroflowmetry nomogram in Iranian children aged 7 to 14 years

Background

As the voiding habits of Iranian children differs from other children because of some cultural and religious considerations, we aimed to establish normal reference values of urinary flow rates in Iranian children between 7 to 14 years of age.

Methods

Eight hundred and two uroflowmetry studies were performed on children with no history of a renal, urological, psychological or neurological disorder, between the ages 7 and 14. Five hundred twenty five studies from 192 girls and 335 boys were considered in this study excluding the staccato/interrupted voiding pattern or voided volume less than 20 ml. The voiding volume, the maximum and average urinary flow rates were extensively analyzed.

Results

The maximal and average urine flow rate nomograms were plotted for both girls and boys. Mean maximum urine flow rate was 19.9 (ml/sec) for boys and 23.5 (ml/sec) for girls with a mean voided volume of 142 (ml) for boys and 147 (ml) for girls. Flow rates showed a close association with voiding volume in both sexes. The maximum and average flow rates were higher in girls than in boys, and they showed a significant increase in flow rates with increasing age, where boys did not. The mean maximum urine flow rates (19.9 ml/sec for boys and 23.5 ml/sec for girls) were found to be higher in this study than other studies.

Conclusion

Nomograms of maximal and average flow rates of girls and boys are presented in centile form, which can help the physician to evaluate the response to medical or surgical treatment and be useful for the screening of lower urinary tract disturbances in children, for a wide range of voided volumes.     

1024例儿童尿流率调查

目的 寻求长沙地区儿童尿流率正常值及其列线图。方法 对1024名正常儿童进行1048次尿流率检测。将所得资料按性别、年龄、体表面积、排尿量分组后进行统计学分析，并绘制出各组相应的列线图以阐明尿量、体表面积、平均尿流率、最大尿流率4者的相互关系。结果 正常儿童尿流率曲线为典型的钟形曲线。〈7岁男性儿童的最大尿流率随年龄增加而增加，年龄每增加1岁最大尿流率增加1．7ml／s，〉7岁者其最大尿流率同成年人相仿。〈9岁女性儿童的最大尿流率随年龄增加而增加，年龄每增加1岁最大尿流率增加1．2ml／s，〉9岁其最大尿流率同成年人相近。儿童最大尿流率、平均尿流率及排尿量均随体表面积增加而增加，同时，最大尿流率、平均尿流率也均随排尿量的增加而增加。结论 〈9岁的女童和〈7岁的男童最大尿流率的正常值有明显的年龄依从性。     

Maximum and average urine flow rates in normal male and female populations--the Liverpool nomograms

The study of voiding in men and women has been handicapped by the lack of a normal reference range covering urinary flow rates over a wide range of voided volumes. Normal volunteers (331 males and 249 females) were studied. Each voided once into a calibrated Dantec Urodyn 1000 mictiograph. On a second occasion 282 men and 46 women voided. The maximum and average urine flow rates of the first voids in both sexes were compared with the respective voided volumes. Nomogram charts, in centile form, for both the maximum and average urine flow rates were constructed using statistical transformations of the data. Males showed a significant decline in both urinary flow rates with age, although there was no statistically significant variation in either urine flow rate with respect to first versus repeated voiding. Females showed no statistically significant variation in either urine flow rate with respect to age, parity or first versus repeated voiding. The maximum and average urine flow rates in both sexes showed an equally strong relationship to voided volume. No artificial restriction of voided volume, e.g. minimum 200 ml, appeared appropriate. These nomograms offer reference ranges for both maximum and average urinary flow rates in both sexes covering a wide range of voided volumes (15-600 ml).     

Age related flow rate nomograms in a normal pediatric population

Uroflow studies in a normal pediatric population were analysed statistically. Single studies for 511 subjects (272 boys and 239 girls) were reviewed. Nomograms relating peak flow to volume voided and age 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. The mean values of peak flow rate increased with volume voided in both sexes and also with age in the male population. Different sets of nomograms, which are necessary for daily clinical evaluation, are given. They define the normal values in the normal population.     

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.     

Ventricular volume change in childhood

OBJECT: The aim of this study was to construct a model of age-related changes in ventricular volume in a group of normal children ages 1 month to 15 years, which could be used for comparative studies of cerebrospinal fluid circulation disorders and cerebral atrophy developmental syndromes. METHODS: A magnetic resonance imaging-based segmentation technique was used to measure ventricular volumes in normal children; each volume was then plotted against the child's age. In addition, intracranial volumes were measured and the ratio of ventricular to intracranial volume was calculated and plotted against age. The study group included 71 normal children, 39 boys and 32 girls, whose ages ranged from 1 month to 15.3 years (mean 84.9 months, median 79 months). The mean ventricular volume was 21.3 cm3 for the whole group, 22.7 cm3 in boys and 19.6 cm3 in girls (p = 0.062, according to t-tests). The mean ventricular volume at 12 months for the whole group was 17 cm3 (20 cm3 in boys and 15 cm3 in girls), representing 65% of the volume achieved by 15 years of age (87% in boys and 53% in girls). The volume increased by a factor of 1.53, to 26 cm3 (23 cm3 in males and 28 cm3 in females, increase factors of 1.15 and 1.86, respectively) at 15 years of age. The change in ventricular volume with age is not linear, but follows a segmental pattern. These age periods were defined as: 0 to 3, 4 to 6, 7 to 10, and 11 to 16 years. A statistical difference based on sex was only demonstrated in the first 6 years of life. The mean ventricular volume for the first 6-year period was 22.4 cm3 in boys and 15.7 cm3 in girls, and the difference was significant for the two sexes (linear regression analysis for age and sex, significant according to analysis of variance regression at 0.007, p = 0.108 for age, p = 0.012 for sex). Thereafter, there was no significant difference in ventricular volume between boys and girls with further growth. The ratio of ventricular volume to intracranial volume was 0.0175 for the whole group, 0.017 in boys and 0.018 in girls (p = 0.272, according to t-tests). At 12 months of age the ratio was 0.019; it stabilized to 0.015 at 8 years of age, and increased to 0.018 at 15 years of age. No statistical difference based on sex was demonstrated with growth. CONCLUSIONS: The ventricular volume in normal children increases with age by a factor of 1.5; the increase is in a nonlinear segmental pattern. Boys have significantly higher ventricular volumes only in the first 6 years of life. The ventricular/intracranial volume ratio remains stable throughout childhood.     

High urinary flow in women with stress incontinence: corrected flow–age nomogram evaluation after a transobturator tape procedure

Introduction and hypothesis

We noninvasively compared urinary flow in both pre- and post-transobturator tape (TOT) procedures in stress urinary incontinence (SUI) patients using previously reported corrected flow–age nomograms in healthy women.

Methods

This retrospective cohort study included patients who underwent a successful TOT procedure to treat SUI. Non-instrumented uroflowmetry was performed before and 3 months after surgery. Corrected maximum flow rate (cQmax) and average flow rate (cQave) were calculated using Qmax/√voided volume (VV) and Qave/√VV respectively. The ratio of corrected flow to age-adjusted corrected flow in healthy women was calculated in each patient. Each parameter was compared against pre-TOT and 3-months post-TOT values.

Results

Sixty-two patients were eligible for study inclusion. All urinary flow parameters were significantly higher pre-TOT than at 3 months post-TOT. The number of patients with cQmax and cQave over mean flow–age nomogram, compared with healthy women, before the TOT procedure decreased 3 months post-TOT; however, in many patients, cQmax and cQave were higher than in the corrected flow–age nomogram post-TOT. No significant difference in the ratio of cQmax to age-adjusted cQmax between pre- and post-TOT in the normal urinary flow group was observed, but significantly decreased in the high urinary flow group 3 months after TOT.

Conclusions

Urinary flow rates were higher in SUI patients compared with age-matched controls and successful TOT procedures normalized urinary flows in patients with high urinary flow. A simple evaluation of urinary flow using a corrected flow–age nomogram may be clinically useful in SUI patients.

     

Measurement of urinary flow rate using ultrasound in young boys and infants

PURPOSE: We present a technique for measuring urinary flow rates with ultrasound in male infants and children. MATERIALS AND METHODS: Urinary flow rate was measured simultaneously by an ultrasound probe placed around the base of the penis and by a funnel with a rotating disk at the bottom in 30 boys with a mean age of 6.7 years (range 4.5 to 10.5), and by ultrasound in 8 infants with a mean age of 10 months (range 1 to 28). Voided volume was measured with a graded cylinder or calculated from the weight change of diapers in infants. Ultrasound and rotating disk maximum flow rates were calculated. The ultrasound signal was calibrated by comparing the collected voided volume to the area under the curve for that void. The volume calculated from the rotating disk flow rate curve was also compared with the collected volume. RESULTS: Both methods yielded similar flow curves. However, ultrasound maximum flow rate significantly exceeded rotating disk maximum flow rate (13 +/- 6 ml. per second, range 5 to 22 versus 10 +/- 4 ml. per second, range 4 to 21, t test p <0.001). The underestimation of the flow rate by the rotating disk method may have been due to adherence of urine to the funnel wall. Rotating disk maximum flow rate was lower and voided volume was underestimated by up to 50% (average 15 +/- 2%) in 21 cases. Ultrasound maximum flow rate averaged 6 +/- 3 ml. per second (range 3 to 11.6 [oldest infant]) in the 8 infants. CONCLUSIONS: Urinary flow rates can be measured accurately using ultrasound in boys who produce small volumes and/or who are not toilet trained and also in infants. In future studies ultrasound will be applied to subsets of male infants with bladder dysfunction.     

Plasma dilution and the rate of infusion of Ringer's solution

Changes in the volume of the fluid space expanded by i.v. infusion of Ringer's acetate solution have been analysed recently using mathematical models. Data obtained by such analyses allow simulation of the dilution of the plasma volume during infusion of the solution at different rates. To obtain basic kinetic data for such simulations, the plasma dilution-time curves were measured during and after i.v. infusion of Ringer's solution 25 ml kg-1 over 30 min in 15 healthy male volunteers (mean age 31 yr) and over 30, 45 and 80 min in six females (mean age 32 yr). Based on these experiments, nomograms were constructed from which the rate of infusion of Ringer's solution and the infusion time required to obtain a defined plasma dilution in both males and females can be estimated together with the infusion rate needed to maintain the dilution at the level reached.      

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, 8,848 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.     

Quantitative Tibial Ultrasonometry Versus Radiographic Phalangeal Absorptiometry in a Caucasian Pediatric Population

There is a need for a reliable bone assessment technique in children. In this study, we compare an existing technique used in children, radiographic absorptiometry (RA), with a relatively novel technique, quantitative tibial ultrasonometry (QUS). In a prospective cohort study, we enrolled 290 girls (mean age 12.7 years) and 273 boys (mean age 12.4 years). Radiographs of the left hand and the left index finger were taken with an aluminium reference wedge within the field of exposure. Radiographic absorptiometry on the second middle phalanx at the mid-level (BMD50%) and proximal quarter (BMD25%) was performed with interactive software. Tibial QUS was performed using the SoundScan Compact. Multiple regression analysis showed that SOS correlated significantly with BMD25% for both boys (r = 0.65, P < 0.001) and girls (r = 0.59, P < 0.001), taking into account age and gender. The same applied for the correlation between speed of sound (SOS) and BMD50% in boys (r = 0.62, P < 0.001) and girls (r = 0.67, P < 0.001). Cubic regression between calendar age and BMD25% showed the best fit for both boys (r2 = 0.60) and girls (r2 = 0.60). For BMD50% a difference in regression was found between boys and girls. Quadratic regression gave a satisfactory fit for boys (r2 = 0.61 ) whereas for girls, a cubic relation was best (r2 = 0.59). Overall, there was a significant correlation between BMD25% and BMD50% for boys r = 0.89 and for girls r = 0.91 (both P < 0.001). Our data show a significant correlation between two different bone assessment techniques. In addition, these data suggest that both tibial ultrasonometry and RA are useful techniques in children.     

Sex difference of urinary osmolality in German children

BACKGROUND/AIMS: Origin of sex difference in urinary osmolality. METHODS: In 495 healthy children aged 4.0-14.9 years participating in the DONALD (Dortmund Nutritional and Anthropometric Longitudinally Designed) study (247 boys, 248 girls), the water intake recorded in 24-hour weighed dietary records along with urinary volume, osmolality and free water reserve in 24-hour urine samples from the same day as the dietary record were determined. RESULTS: Boys showed a significantly higher energy intake, total water intake, urinary osmolality and osmolar load than girls but no increase in urinary volume. When referred to energy intake, mean urinary volume and mean free water reserve were significantly higher in girls than boys. Girls could have a preference for food with a higher water density and lower non-renal water losses. CONCLUSION: German girls of the DONALD study displayed a lower urinary osmolality than German boys due to a relatively higher urinary volume. The sex difference could be caused by a higher water density of the ingested food (ml/kcal) and a lower insensible water loss (ml/kcal) in girls than boys.     

Lung function of healthy boys and girls in Jamaica in relation to ethnic composition, test exercise performance, and habitual physical activity

Miller, G. J., Saunders, M. J., Gilson, R. J. C., and Ashcroft, M. T. (1977).Thorax, 32, 486-496. Lung function of healthy boys and girls in Jamaica in relation to ethnic composition, test exercise performance, and habitual physical activity. The relationships of forced expiratory volume and forced vital capacity on height, age, sex, area of residence, and ethnic composition were assessed in 622 children in Jamaica. Rural children in hill-farming communities were judged to have a higher habitual physical activity than urban children. Allowing for differences in body size, forced vital capacity averaged 3% greater in rural children than in urban children, 7% less in girls than in boys, and 16% greater in children of European origin than in children of African descent.     

A statistical study of the effects of urethral instrumentation on urine flow in women

Data were obtained from a retrospective review of the records of 125 women who had undergone full urodynamic studies for a variety of clinical indications, to determine whether urethral instrumentation has an adverse effect on the parameters of urine flow in women. All patients had an initial urine flow study with a spontaneous void of at least 100 ml, after which they were catheterized to measure the postvoid residual urine. All patients then underwent urethral pressure studies, complex filling cystometry, pressure-flow voiding studies and urethrocystoscopy, after which they underwent another spontaneous non-instrumented urine flow study. Peak and mean flow rates were analysed statistically by blocked analysis of variance. The data were corrected for the effects of the volume voided by converting the flow rates into a nomogram percentile ranking using a computer program.Statistical analysis indicated that peak flow rates increased from an average of 21.7 ml/s (SD±10.8 ml/s) before instrumentation to 24.3 ml/s (SD±10.5 ml/s) after instrumentation (P=0.0045). Mean flow rates also increased from 12.0 ml/s (SD±7.3 ml/s) before instrumentation to 13.3 ml/s (SD±7.3 ml/s) after instrumentation (P=0.0365). However, when these data were corrected for the effects of the volume voided, both the average peak nomogram percentile and the average mean nomogram percentiles were reduced, from 29.1% to 24.2% for the peak flow rate (P=0.0426) and from 32% to 27.9% for the mean flow rate (P=0.1019).The corrected data indicate that both peak and mean flow rates are reduced in women following urethral instrumentation. The reduction in flow for peak flow rates is statistically significant. The reduction in mean flow rates did not reach this level of significance. This must be kept in mind when female patients are being evaluated for possible voiding disorders. Further prospective studies of the effect of urethral instrumentation on urine flow in women would seem to be indicated.     

Timed micturition and maximum urinary flow rate in randomly selected symptom-free males

OBJECTIVE: To establish normal ranges for timed micturition, i.e. the time to void the first 100 ml, study its dependency on voided volume and age and compare it to maximum flow rate. MATERIAL AND METHODS: Randomly selected men from the National Register without voiding symptoms were investigated. These 58 men (aged 30-75 years) registered 1286 voidings (median 21 per person) at home with the aid of a portable uroflowmeter. Timed micturition and maximum flow rate were obtained from the same voidings. RESULTS: An increase in timed micturition with an increase in age was confirmed. When estimating normal ranges it was sufficient to use the age groups < or = 55 years and > or = 56 years. Maximum flow rate is shown in nomograms with voided volume. Timed micturition had less dependency on voided volume than maximum flow rate. The normal ranges of timed micturition are < or = 9 s for men aged < or = 55 years and < or = 15 s for those aged > or = 56 years. The true median of timed micturition for men aged > or = 56 years may be 6 s lower or 2.5 s higher than the value of a single measurement. Corresponding figures for maximum flow rate are 5 and 6 ml/s. CONCLUSIONS: Timed micturition has a low dependency on volume and values of < or = 9 s and < or = 15 s are normal for men aged < or = 55 years and > or = 56 years, respectively.     

Assessment of serum prostate specific antigen in childhood

OBJECTIVE: To investigate serum prostate specific antigen (PSA) levels with age and sex in childhood. SUBJECTS AND METHODS: This prospective study included 205 children (123 boys, 82 girls; mean age 59.27 months, sd 3.78, range 2 days to 204 months) with no urogenital or endocrine disorders. PSA levels were measured using a highly sensitive, "third-generation" PSA (time-resolved immunofluorometric) assay, able to detect PSA levels of > or = 1 ng/L (0.001 ng/mL). Children were divided into four groups by age, i.e. A (0-12 months; 34 boys/20 girls); B (13-48, 37/21); C (49-144, 41/32); and D (> 144, 11/9). The data were analysed statistically using analysis of variance. RESULTS: An accurate measurement of PSA was possible in both sexes using the assay. The median (sd, range) PSA level in boys was 38.41 (1.318, 1-2768) ng/L, and in girls 4.059 (1.392, 1-287) ng/L. There were no significant differences between girls at all age groups, or between the sexes for groups A-C, but levels were significantly higher in boys in group D (30 times that in girls), at 142.59 (1.53) and 4.85 (1.58) ng/L (P < 0.01). CONCLUSIONS: PSA levels do not differ significantly between boys and girls until 12 years old, after which there is a significant and steep increase in PSA in boys, reflecting the development of the prostate. Assessing PSA in children could be used as a potential marker in the diagnosis and follow-up of urogenital disorders.     

Low-back pain and straight leg raising in children and adolescents

The relation between a history of low-back pain (LBP) and straight leg raising (SLR) was investigated in 267 children (6-13 years) and 135 adolescents (14-18 years). The prevalences of a history of LBP and low mean SLR values were significantly greater in the older age group. In each age group, boys had significantly lower SLR values than girls. No significant difference in straight leg raising was found between those subjects with and those subjects without a history of low-back pain except for male adolescents, for whom there was a significant direct relation between a history of LBP and decreased SLR.     

Normal changes in orbital volume during childhood

OBJECT: The aim of this study was to construct a model of changes in orbital volume that occur throughout childhood from the age of 1 month to 15 years, which could be used for comparative studies of disease states affecting orbital growth. METHODS: Using the procedure of segmentation on magnetic resonance images obtained in 67 healthy children, orbital volume was measured and plotted against age. During the first few months of life left orbital volume is on average 15 cm3 in male and 13 cm3 in female infants; these volumes increase to 26 cm3 and 24 cm3, respectively, by the time the child reaches 15 years of age. During the first few months of life right orbital volume is on average 16 cm3 in male and 13 cm3 in female infants; these volumes increase to 27 cm3 and 25 cm3, respectively, by the time the child is 15 years old. This represents an overall increase in orbital volume by a factor of 1.7 in boys and 1.8 in girls. By the time the child has reached 5 years of age, the orbital volume for both right and left sides has reached on average 77% of the volume seen at 15 years in both sexes. The differences between the two sides are not statistically significant for either sex. The change in orbital volume that is associated with age in general displays a linear pattern. Throughout childhood, orbital volumes are larger in boys than in girls, but share a similar growth pattern. The difference between the two sexes tends toward statistical significance during the first 5 years of life (left orbit p = 0.1, right orbit p = 0.04). CONCLUSIONS: During early childhood, orbital volume increases in a linear fashion, achieving a significant proportion of its final growth by the time the child is 5 years old.