Clinical evaluation and comparison of the Infrasonde, Arteriosonde, and mercury sphygmomanometer in measurement of blood pressure in children

20 years on - the measurement of blood pressure and detection of hypertension in children and adolescents: a national descriptive survey

In 1997 a survey identified a general lack of standardisation of blood pressure (BP) measurement and little consensus on the criteria for diagnosing hypertension amongst paediatricians. We have conducted a new online survey in 2021, to compare clinical practice between the two time periods. A national quality improvement survey was approved by the GAPRUKI committee and then circulated to consultant-grade general paediatricians. 125 analysable replies from 34 different sites were received and compared with the 1997 data. 106 (84.8%) reported clinic nurse involvement in BP measurement, more than twice than reported previously (40.6%). Most paediatricians (53.6%) now rely on oscillometric devices, whereas the mercury sphygmomanometer was favoured previously (82.7%). If assessing BP manually (n = 89), most (79.8%) now use Korotkoff phase V as the auscultatory endpoint for diastolic BP (phase IV was previously used (52.1%)). Diagnostic criteria of hypertension, the criteria (≥95th centile for gender, age and height) were constant, and 100% of paediatricians diagnosed it using systolic BP, but only 43 (34.4%) used diastolic BP, a decrease from 79.4% previously. Ambulatory BP Monitoring was six times more available than in 1997 (81.6% vs 13.6%). Similar to previous findings, only 12 (9.6%) paediatricians would manage hypertensive patients themselves, however 82 (72.6%) would keep general paediatric input. There have been important changes in the assessment of BP in children, including increased nurse involvement and greater use of technology. However, fewer paediatricians are responding to high diastolic pressures than twenty years ago.

History of blood pressure measurement in newborns and infants

The development of methods for measuring blood pressure (BP) in newborns and small children has a rich history. Methods for BP measuring in adults had to be adapted to this age group. For measuring BP in direct invasive way, a suitable approach had to be found to access the arterial circulation through the umbilical and later radialis artery. Currently, results obtained from direct invasive BP measurement are considered the "gold standard". The development of non-invasive methods for BP measuring in newborns and children began with the use of von Basch's sphygmomanometer (1880). In 1899, Gustav Gärtner constructed the device, which was the basis for the flush method. After the discovery of the palpation and auscultation methods, these methods were also used for BP measurement in newborns and children, however, the BP values obtained in these ways were typically underestimated using excessively wide cuffs. From the auscultation method, methods utilizing ultrasound and infrasound to detect arterial wall movement and blood flow were later developed. The oscillometric method for BP measurement was introduced by E. J. Marey so early as in 1876. In 1912, P. Balard used the oscillometric technique to measure blood pressure in a large group of newborns. Through different types of oscillometers using various methods for detecting vascular oscillations (such as xylol method, impedance and volume plethysmography, etc.), the development has continued to assessment of vascular oscillations by modern sensor technology and software. For continuous non-invasive blood pressure measurement, the volume-clamp method, first described by Jan Peňáz in 1968, was developed. After modification for use in newborns, application of the cuff to the wrist instead of the finger, it is primarily used in clinical physiological studies to evaluate beat-to-beat BP and heart rate pressure variability, such as in the determination of the baroreflex sensitivity.

Managing severe hypertension in children

Severe childhood hypertension is uncommon and frequently not recognised and is best defined as a systolic blood pressure (SBP) above the stage 2 threshold of the 95th centile + 12 mmHg. If no signs of end-organ damage are present, this is urgent hypertension which can be managed by the slow introduction of oral or sublingual medication, but if signs are present, the child has emergency hypertension (or hypertensive encephalopathy if they include irritability, visual impairment, fits, coma, or facial palsy), and treatment must be started promptly to prevent progression to permanent neurological damage or death. However, detailed evidence from case series shows that the SBP must be lowered in a controlled manner over about 2 days by infusing short-acting intravenous hypotensive agents, with saline boluses ready in case of overshoot, unless the child had documented normotension within the last day. This is because sustained hypertension may increase pressure thresholds of cerebrovascular autoregulation which take time to reverse. A recent PICU study that suggested otherwise was significantly flawed. The target is to reduce the admission SBP by its excess, to just above the 95th centile, in three equal steps lasting about ≥ 6 h, 12 h, and finally ≥ 24 h, before introducing oral therapy. Few of the current clinical guidelines are comprehensive, and some advise reducing the SBP by a fixed percentage, which may be dangerous and has no evidence base. This review suggests criteria for future guidelines and argues that these should be evaluated by establishing prospective national or international databases.

Single blood pressure chart for children up to 13 years to improve the recognition of hypertension based on existing normative data

OBJECTIVE

To produce a single 'growth-chart-style' blood pressure (BP) chart with clear diagnostic thresholds to assist paediatricians to make prompt and accurate diagnoses of hypertension.

DESIGN

The well-established but complex published data on normal BP ranges in prepubertal children were identified and analysed to determine if it was possible to produce a single, user-friendly, colour-coded chart, showing diagnostic hypertension thresholds for systolic and diastolic BP without losing clinically important information.

RESULTS

There were sufficient published normative childhood BP data available to define systolic and diastolic BP centiles from term onwards but only sufficient to determine systolic BP centiles from 28 weeks of gestation to term. Up to 13 years of age, it was possible to combine boys' and girls' data without loss of precision and to define the threshold between stage 1 and stage 2 (severe) hypertension as the 95th centile +12 mm Hg. This allowed the production of single colour-coded charts for systolic and diastolic BP and to advise on making simple adjustments for the impact of stature on individual children's results.

CONCLUSIONS

A simplified, integrated BP chart with colour-coded diagnostic thresholds was produced to assist the prompt diagnosis of hypertension in prepubertal children. This information could be included into a Paediatric Early Warning System score.

Randomized trial comparing dopamine and dobutamine in preterm infants

The aim of this study was to compare the efficacy of two inotropic infusions in treating low BP in preterm neonates. Forty infants with median gestational age 27 weeks (range 23-33) were studied. At trial entry the infants, who all had a systolic BP < 40 mmHg despite receiving a colloid infusion, were randomized to receive either a dopamine or dobutamine infusion. The infusions were commenced at a rate of 5 micrograms/kg per min and, if necessary, this was increased over the 3 h study period to 15 micrograms/kg per min. There was no significant difference in the gestational or postnatal age or baseline BP of the 20 infants who received dopamine and those 20 who received dobutamine. Three hours after commencing the infusions, although there was no difference in the rate of inotrope infusion between the two groups, the infants who received dopamine had a significantly higher systolic BP, a median of 39 mmHg (range 30-58) compared to a median of 34 mmHg (range 21-46) in the dobutamine group, P < 0.05. In addition, 10 infants who received dopamine, but only 3 who received dobutamine, had a systolic BP > 40 mmHg (P < 0.05). We conclude that dopamine rather than dobutamine infusion is more efficacious in improving the BP of preterm neonates.

Cardiac function and sympathoadrenal activity in the newborn after cesarean section under spinal and epidural anesthesia

Left ventricular systolic time intervals, bupivacaine concentrations, adrenaline and noradrenaline levels were determined in 19 neonates delivered by elective cesarean section. Ten of the cesarean sections were performed under spinal and nine under epidural anesthesia. Plain bupivacaine 0.5% was used for the epidural anesthesia and bupivacaine 0.5% in glucose 8% for the spinals. The noradrenaline and adrenaline levels were higher in the neonates whose mothers received epidural anesthesia. The differences in catecholamine and bupivacaine concentrations were not associated with differences in left ventricular dynamics, or the timing of postnatal circulatory changes. The significant exposure of the neonate to bupivacaine, at maternal epidural anesthesia, seems to have no negative effect on early neonatal circulation in the healthy term infant.

Evaluation of the measurement of children's blood pressure in an epidemiological multicentre study

Reliability and repeatability of blood pressure (BP) measurements performed by both a local nurse and a control nurse visiting all five study areas in the Finnish Multicentre Study were analysed. As an objective control, Rose's tape recordings were played at least three times during the study period to each nurse. It was found that the nurses differed from each other with variations of 2.5 mm Hg, 54.6 mm Hg and 17.9 mm Hg in the recordings of systolic, diastolic Korotkoff's IV (KIV) phase and diastolic KV phase sounds respectively, in assessing the tape. Correlation coefficients between the systolic BP and diastolic BP measurements made by the local and control nurses in 3-year-old children varied from 0.10 to 0.72 and from -0.16 to 0.46 respectively. Correlation coefficients in 6-18-year-old subjects between systolic, diastolic KIV and diastolic KV BP measurements made by the control and local nurses varied from 0.69 to 0.81, from 0.42 to 0.63 and from 0.38 to 0.58 respectively. All of the nurses had a significant terminal digit preference and it was pronounced in two of them. Because of these findings it was concluded that comparisons of BP values in different areas should be done cautiously.

Concurrent validity studies of blood pressure instrumentation. The Philadelphia Blood Pressure Project

There is increasing evidence that blood pressure (BP) screening during adolescence may detect early evidence of hypertensive disease. Choice of instrumentation becomes important to maximize the accuracy and interpretive value of several serial readings. We therefore conducted two studies of adolescents, comparing auscultatory (Baumanometer and Random-zero), ultrasonic (Arteriosonde 1216), and infrasonic (Physiometrics SR-2) devices. These instruments were compared serially (Study 1) for older adolescents (n = 48). The Baumanometer, Arteriosonde 1216, and Physiometrics SR-2 were compared both serially and simultaneously (Study 2) for younger and older adolescents (n = 24). In both studies, the order of device presentation was completely counterbalanced. In Study 1, reliability estimates were high (r greater than 0.65), with the exception of the Arteriosonde 1216 diastolic readings, and the Physiometrics SR-2 yielded significantly lower mean diastolic BP readings than the other devices. Diastolic Phase V readings taken with the Random-zero were significantly higher when the Random-zero was presented at the end of the sequence of instrument presentation. This order of presentation effect is probably attributable to the need for overinflation when using the Random-zero device and may cause an overestimation of diastolic BP in the young. In Study 2, again the Arteriosonde 1216 did not perform reliably in recording diastolic BP. Further, the Physiometrics SR-2 device, although reliable, yielded diastolic readings significantly lower (p less than 0.001) than diastolic Phase IV readings taken both serially and simultaneously.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulse wave patterns in patent ductus arteriosus

Pulse wave patterns were analysed in 10 term and 10 preterm infants with patent ductus arteriosus (PDA) and in 2 matched control groups. A non-invasive technique was used to record the pulse waves from the axillary artery. The pulsatile ratio was calculated as the quotient between the amplitude of the incisural notch and the peak of the pulse wave above the end diastolic baseline. The pulsatile ratio was considerably lower in preterm and term infants with PDA compared with the ratio after closure of the ductus and the ratio in control infants. A pulsatile ratio less than 0.50 indicates the presence of a large PDA whereas a ratio over 0.55 is normal. The technique may be used to document and evaluate arterial pulse wave patterns and may be a useful diagnostic tool.

Left ventricular systolic time intervals in preterm infants with patent ductus arteriosus

Left ventricular systolic time intervals were recorded by a non-invasive technique, from the axillary artery, in 13 preterm infants with patent ductus arteriosus. At the onset of clinical symptoms, consistent with a large left-to right ductal shunt, the preejection intervals were shorter than in a control group of nine preterm infants without a patent ductus. The most pronounced difference was found in the shortening of the isovolumic contraction time, 10.7 msec in the ductus group compared with 22.4 msec in the control group. Ductal closure normalized the isovolumic contraction time to 22.1 msec. The very short preejection intervals, associated with a large ductal shunt, are suggested to reflect a combination of reduced aortic diastolic pressure and increased left ventricular filling pressure. In spite of increased volume load to the left ventricle there were no detectable changes in the systolic time intervals indicating impaired left ventricular function. The left ventricle seems to be competent to handle increased volume load in the presence of reduced afterload in preterm infants with symptomatic left-to right ductal shunts.

Assessment of left ventricular adaptation to extrauterine circulation

Left ventricular systolic time intervals (STI) were recorded by non-invasive technique from the axillary artery in fifteen normal newborns from 10-15 min to 70-74 hours after birth. The observed changes in the different STI could almost entirely be related to changes in the isovolumic contraction time (ICT). At the early postnatal recording ICT was only 21.0 msec suggesting an enhanced left ventricular performance compared to prenatal observations. During the following hours ICT increased to 31.6 msec which in some infants may imply a reduced left ventricular performance. This is suggested to coincide with ductal closure.

Clinical evaluation of the Dinamap non-invasive blood pressure monitor in pre-term neonates

The performance of the Dinamap 847 non-invasive blood pressure monitor was evaluated in a group of 10 severely ill pre-term newborn babies. The mean gestational age was 30 weeks and mean birthweight of 1610 gm. The values of systolic, diastolic and mean arterial pressure obtained by the Dinamap were compared with the corresponding values of actual pressure through a right radial artery catheter. All these values showed a high degree of correlation. No complications were noted. It was concluded that the Dinamap 847 should be considered as an alternative for monitoring the arterial blood pressure in pre-term neonates where arterial catheterisation is either not justified or impossible.

Impaired weight gain and renovascular hypertension

An eight month old infant was admitted to hospital because of poor weight gain. During the hospitalization she became unconscious and had convulsions. On these occasions a high blood pressure (205/120 mm Hg) was measured. In further evaluation of the hypertension, high plasma renin activity (32.8 ug/l/h) with a high serum aldosterone concentration (13000 pmol/l) was measured. Because of these findings renal angiography was performed: this revealed a stenosis of the left renal artery. A reconstruction of the renal artery was performed by a microsurgical technique and nine months after the operation the child was only mildly hypertensive but still required antihypertensive medication (propranolol 10 x 3, hydralazine 5 mg x 2): with this treatment her blood pressure was 110/80 mm Hg. After the operation her weight rose from below 2.5 percentile to the 10th percentile. The importance of blood pressure measurement in all children and infants admitted to hospital, regardless of their symptoms, is stressed.

Exercise-induced proteinuria in children and adolescents

Urinary albumin and beta 2-microglobulin excretion rates were measured by radioimmunological methods in 60 children and adolescents at rest and during physical exercise. The geometric mean of the albumin excretion rate was 4.4 (microgram/min)/m2 at rest and rose to 7.9 (micrograms/min)/m2 during exercise (P less than 0.001), while the geometric mean of beta 2-microglobulin was 31.9 (ng/min)/m2 at rest and 26.2 (ng/min)/m2 during exercise. These results indicate that exercise-induced proteinuria is of a glomerular leaking type. The albumin excretion rate was not dependent on the age or sex of the subjects. The exercise-induced albuminuria correlated weakly but significantly with the maximal blood pressure (r = 0.27; P less than 0.05) and with the physical fitness of the subjects (r = 0.28; P less than 0.05).

Changes in blood pressure during the first year of life

Changes in blood pressure during the first year of life were investigated in a one-year follow-up study. The blood pressures were measured at the age of one day from 245 newborns, at the age of four or five days from 224 infants, at the age of four months from 105 infants, and at the age of one year from 68 infants. Blood pressure increased considerably during the first five days. The increase of mean systolic blood pressure was markedly bigger, from 59 to 90 mmHg, than that of mean diastolic blood pressure, which was from 43 to 55 mmHg. The correlations of blood pressure were calculated with prenatal history, physical measurements and parental blood pressure. Significant correlations were found with physical factors but not with the prenatal history or parental blood pressure. The tracking of the blood pressure was not good. The distribution of the blood pressure values was normal. It is concluded that for the time being there are no reliable predictive factors to hypertension which could be found in early infancy.