Measurements of central blood vessels in infants and children: Normal values

In order to provide physicians interpreting vascular radiographic studies with normal data regarding central blood vessel size in children and to facilitate the design and adaptation of intravascular devices for pediatric use, we measured lengths and diameters of central blood vessels in 141 radiographic studies in 136 children. The diameters of the following vessels were determined: right and left internal jugular veins and common carotid arteries; the inferior vena cava and the descending thoracic aorta; right and left iliac veins; and right and left femoral veins and arteries. In addition, the lengths of the inferior vena cava and the descending aorta were also determined. Blood vessel dimensions were highly correlated with age, height, weight, and body surface area. The linear regression equations for each measured dimension against age, weight, height, and surface area are provided, along with a table of predicted vessel size as a function of age.     

Normal values of signal-averaged electrocardiographic parameters and QT dispersion in infants and children

Ventricular late potentials, and dispersion of the QT interval, are markers for risk of ventricular arrhythmias. Normal values for these parameters are well established in adults, but may not apply for children. This study has investigated the age dependency of signal averaged electrocardiographic parameters and QT dispersion in 111 normal children aged from 5 days to 16 years. The results indicate that parameters change with age: duration of filtered QRS and low amplitude (< 40 microV) terminal signal increase with age, especially in the younger patients. Filtered QRS is 88.9 +/- 7.87 ms in infants, and increases to 108.7 +/- 8.51 in teenagers (p<0.001). Low amplitude terminal signals are 17.0 +/- 3.44 ms in infants, and 24.5 +/- 5.64 ms in teenagers (p<0.001). Root mean square of the last 40 ms decreases with age, but remains stable after the age of 10 years (122.4 +/- 33.30 microV in infants, 60.9 +/- 31.27 in teenagers, p<0.001). QT dispersion, on the other hand, does not change significantly with age. The mean value for the whole group is 36 +/- 13.7 ms. A weak but significant correlation exists between QT dispersion and filtered QRS. Thus, age must be taken into consideration when interpreting signal-averaged electrocardiograms, but not when measuring QT dispersion.     

Normal spirometric reference values for Omani children and adolescents

OBJECTIVES: Normal lung function has been shown to be population specific. The aim of this study was to derive normal reference spirometric values for Omani children and adolescents. METHODOLOGY: Forced vital capacity (FVC), forced expiratory volume in 1 s (FEV(1)), peak expiratory flow and forced mid-expiratory flow were measured in 837 healthy Omani school children aged 6-19 years. Multiple linear regression analysis was performed for each spirometric parameter against age, height and weight for boys and girls separately. RESULTS: All measured spirometric parameters increased with age and height and were significantly higher in boys than girls. Height explained the maximum variance for all parameters. After accounting for height in the prediction equations, the contribution of age and weight was minimal. The expiratory ratio (FEV(1)%FVC) was independent of age and height and its mean values (+/- standard deviation) were slightly higher in girls (91.1 +/- 6.1%) than boys (86.5 +/- 7.1%; P < 0.001). The predicted normal values of the subjects using the derived equations were between 5 and 10% lower than the respective values for subjects in Caucasian sample groups. CONCLUSION: The developed prediction equations can be used in clinical practice in Oman and can be considered for use in neighbouring Arab countries.     

Hereditary spherocytosis. I. Clinical,hematologic and genetic features in 28 cases,with particular reference to the osmotic and mechanical fragility of incubated erythrocytes

Clinical, hematologic and genetic data on 28 cases of hereditary spherocytosisare presented for the purpose of characterizing this disorder as completely aspossible. On the basis of this experience it is recommended that the followingtypical laboratory findings be sought in establishing a diagnosis in suspectedcases: (1) Presence of spherocytes or abnormally thick red cells in peripheralblood; (2) greater than normal osmotic fragility of the red cells; in cases in whichthe fragility of fresh cells is not significantly increased, determinations should bemade after sterile incubation of the blood at body temperature for 24 hours;(3) greater than normal mechanical fragility of freshly drawn red cells; (4) negative antiglobulin (Coombs) test; (5) greater than normal lysis of the red cellsduring sterile incubation at body temperature for 48 hours; and (6) presence ofsimilar abnormalities in relatives.

Abnormality of the erythrocyte persisted in all of the 11 patients in this seriesfollowed one or more years after splenectomy. An unusual case of chronic hemolytic anemia is described but not included in the numbered series because (1) bothparents were hematologically normal and (2) spherocytosis and abnormally greatosmotic and mechanical fragility and autohemolysis could not be demonstratedafter the fifth postoperative month. Classification of this case is deferred pendingfurther experience.

Demonstration in a parent, sibling or offspring of red cells showing the afore-mentioned abnormalities is necessary for an unequivocal diagnosis, but this requirement cannot always be met because relatives may not be available for examination. Moreover, when parents and/or several siblings are examined withoutpositive findings, low gene expressivity, gene mutation and illegitimacy may beconsidered as explanations. Evidence is cited to suggest the possibility of a lowdegree of penetrance or expression in some cases and to illustrate the need forstill more sensitive laboratory tests that might aid in diagnosis of the mildestforms of this disease. The lower incidence of spherocytosis in siblings of propositithan in offspring of propositi is cited as evidence bearing on the theory of genemutation in some propositi.

A simplified "qualitative" test of osmotic fragility of incubated red cells isdescribed.

Submitted on April 16, 1951 Accepted on May 10, 1951     

Disaccharidases of the small intestine mucosa in infants and children. "Normal values", log normal distribution and age dependence]

In 63 infants and children with a histological normal mucosa of the duodenum, without an isolated defect of enzyme and with a normal increase of xylose and glucose in serum after a combined xylose-lactose loading test the activities of disaccharidases were log normal distributed. The asymmetric distributions were transformed into symmetric ones and the geometric mean (x) as well as the range (+/- 2 s) of maltase, saccharase, isomaltase, lactase and trehalase were calculated. Only the activity of lactase shows a significant dependency on age. In the first year of age the lower limit (x -- 2 s) of this enzyme is much higher than later.     

Normal values for forced oscillatory respiratory resistance in children

Forced oscillatory respiratory resistance was measured in 138 healthy children aged 2- to 16-years-old using a commercial unit. Regression analysis was performed using the resistance measurements obtained at frequencies of 6 Hz and 26 Hz and averages of measurements obtained at frequencies of from 6-26 Hz, 6-10 Hz, and 22-26 Hz. The analysis suggested that regression curves and 95% confidence intervals obtained using a quadratic model with height as the independent variable provided the best prediction of normal values and their ranges. Three independent sets of resistance measurements, which were obtained for all 138 subjects, were used to calculate the average individual coefficients of variation (CV) for the five resistance parameters noted above; these ranged from 9 to 13%. This analysis suggested that the expected CV of repeated measurements would be about 10%. Finally, values from 13 children who had asthma with mild bronchial obstruction (FEV1 less than 80% of predicted) were compared with the normal values derived from the regression curves. Values from all but two of the children fell within the reference intervals, suggesting that FEV1 may be a more sensitive measure of obstruction than forced oscillatory resistance. The main applications of this new approach may be in the evaluation of young children, in following individual patients, and in bronchodilation and bronchial challenge tests.     

Normal vectorcardiographic parameters in infants and children

Normal ranges of 32 parameters in vectorcardiography were determined in 200 healthy infants and children. The subjects were divided into 5 groups and results were compared in each group. Significant differences were found in 11 parameters. The differences were associated with a physiologically prominent right ventricular load in younger age groups. Therefore, age should be considered in evaluation of vectorcardiography.     

Normal polysomnographic respiratory values in children and adolescents

STUDY OBJECTIVES: Polysomnography is important in the evaluation of children and adolescents with sleep-disordered breathing. Adult criteria for obstructive sleep apnea have been shown to be inapplicable to children. Nevertheless, very little data are available regarding normal respiratory parameters during sleep in healthy children and adolescents. The purpose of the study was to characterize normal polysomnography values in healthy children and adolescents and to establish respiratory reference values for pediatric polysomnography. DESIGN, SETTING AND PARTICIPANTS: Seventy healthy, normal children and adolescents were studied. Age ranged from 1 to 15 years (mean +/- SD, 8.02 +/- 4.57 years). All children underwent overnight polysomnography including EEG, electromyography, electrooculography, ECG, pulse oximetry arterial oxygen saturation (SpO(2)), chest wall and abdomen motion, oral and nasal airflow, and end-tidal PCO(2) (PETCO(2)). RESULTS: Three children (4%) had a mean of 0.37 obstructive apneas (OAs) per hour of sleep (1 to 5 OAs per child per study), with mean apnea duration of 10.3 +/- 2.1 s. This was not accompanied with oxygen desaturation. Twenty-six children had one to seven central apneas (CAs) per child, resulting in a mean of 0.4 CAs per hour of sleep (median, 0.33; 97.5 percentile, 0.9). Eleven of the 58 events of CA in six children coincided with oxygen desaturation to a minimum of 88% (nadir apnea desaturation range, 88 to 93%). The mean SpO(2) was 97.2 +/- 0.8% with SpO(2) nadir of 94.6 +/- 2.2%. PETCO(2) > 45 mm Hg occurred for 1.6 +/- 3.8% of total sleep time (TST) in 21 of 70 children (30%), with a distribution of 1.3 +/- 3.03% in the range of 46 to 47 mm Hg; < 0.7% were within the range of 48 to 50 mm Hg; and in 0.29 +/- 0.24% of TST, PETCO(2) values were > 50 mm Hg. CONCLUSIONS: Based on these data, the recommended limits for normal values are as follows: OA index, 1; CA index, 0.9; oxygen desaturation, 89%; baseline saturation, 92%; and PETCO(2) > 45 mm Hg for < 10% of TST.     

Studies on Erythropoietin. I. Demonstration of Erythropoietin in Normal Plasma

1. A modification of a technic wherein hypertransfused rats are used forthe bioassay of erythropoietin is described, and some kinetics of iron incorporation following transfusion are presented.

2. It was possible to detect activity in normal plasma and demonstrate thatplasma of animals whose erythropoiesis is depressed below normal by hypertransfusion possesses less erythropoietin than normal plasma.

3. The variation of response under standardized conditions is sufficientlysmall and sufficiently predictable so that within certain limits, quantitation ispossible. A dose-response analysis is presented.

4. Plasma from normal rats possesses approximately 25 per cent of theactivity found in rats rendered acutely anemic by a standardized blood loss.

Submitted on July 31, 1959 Accepted on April 21, 1960     

A method for the determination of the osmotic fragility of erythrocytes

A method for registration of the haemolysis of erythrocytes as a measure for their osmotic resistance is presented. The technical realization is performed by means of a cuvette head-piece for holding a filter, which separates the investigation material from water. A cuvette insertion guarantees the regular construction of a haemoglobin gradient, serving as a measure for haemolysis, which is photometrically measured in the Spekol (VEB Carl Zeiss JENA) and registered by means of the compensation tape writer G 1 B 1 (VEB Carl Zeiss JENA). 0.3-0.4 ml investigation material are used. The expenditure of time amounts to about 20 minutes.     

Normal values of M mode echocardiographic measurements of more than 2000 healthy infants and children in central Europe

OBJECTIVE—To obtain normal M mode (one dimensional) echocardiographic values in a substantial sample of normal infants and children.
DESIGN—Data were obtained over three years from a single centre in central Europe.
PATIENTS—2036 healthy infants and children aged one day to 18 years.
METHODS—In line with recommendations for standardising measurements from M mode echocardiograms, and using digital echocardiographic equipment, measurements were obtained of the following: right ventricular anterior wall thickness at end diastole, right ventricular end diastolic dimension, thickness of interventricular septum at end diastole and end systole, thickness of posterior wall of the left ventricle at end diastole and end systole, left ventricular dimension at end diastole and end systole, pulmonary and aortic valve diameter, and left atrial dimension.
RESULTS—Measurements are presented graphically on centile charts with respect to body surface area, and as tables with mean and 2 SD values for newborns in relation to body weight, and for infants and children in relation to body surface area. Best fitting regression equations are given for each measured variable, using the 50th centile values.
CONCLUSION—In comparison with previously published normal values, the presented charts and tables make it possible to judge echocardiographic measurements of a particular patient as normal or abnormal.


Keywords: paediatric cardiology; echocardiography; normal values     

Normal values of the growth of the aorta in children. An angiography study

Angiocardiography is a standard procedure for quantification and evaluation of congenital heart disease. Knowledge of the diameters at the level of aortic valve ring, ascending and descending aorta can contribute to the decision in repair of congenital heart disease. Moreover, they are helpful for postoperative follow-up studies. In order to establish normal standards, analysis was performed on 51 cineangiograms obtained from infants, children and adolescents with no evidence of heart disease (n = 16) or only hemodynamically irrelevant cardiovascular malformations (n = 35). The individual diagnoses in these patients appear in the accompanying publication in this issue. Patients with bicuspid aortic valve or subvalvular aortic stenosis were excluded from measurements of the aortic valve ring, the sinus and the ascending aorta. Angiocardiography was performed in a fasting state, after sedation and in the supine position with injections of contrast material in the pulmonary artery and or in the left ventricle and ascending aorta. For purposes of calibration, a grid or the known diameter of the catheter was used. Systolic and diastolic diameters of the aortic valve ring (AO-R), sinus (AO-S) and distal region, between sinus valsalvae and ascending aorta (AO-D), as well as those of the isthmus (DAO-I), postisthmic region (DAO-PI) and descending thoracoabdominal aorta (DAO-T) were measured. To obtain a mean value for each vascular structure, the corresponding systolic and diastolic diameters were averaged. The mean diameter was referenced to body length and body surface area (BSA).(ABSTRACT TRUNCATED AT 250 WORDS)     

A study of plasma free amino acid levels. II. Normal values for children and adults

Mean values for the fasting plasma levels of the individual amino acids are given for 136 children (aged 6–18 yr) and 194 adults. There are statistically significant differences between the mean values of boys and girls for only a few amino acids, but there are highly significant differences between the values for men and women for most of the amino acids. Men have higher levels than women for all the amino acids except glycine, serine, and threonine. Charts showing the mean values and variances of the amino acid levels of children and of men and women have been prepared. These allow a convenient medium on which to plot plasma amino acid analyses for easy detection of abnormal blood levels.