Comparison of auscultatory and oscillometric blood pressures

OBJECTIVE: To study the differences in blood pressure readings between the auscultatory and oscillometric (Dinamap model 8100; Critikon, Tampa, Fla) methods. DESIGN: Survey of 2 blood pressure instruments. SETTING: Public schools. PARTICIPANTS: Seven thousand two hundred eight schoolchildren aged 5 through 17 years. MAIN OUTCOME MEASURE: Blood pressure levels. RESULTS: For all children combined, Dinamap systolic pressure readings were 10 mm Hg higher (95% confidence interval, -4 to 24 mm Hg) than the auscultatory systolic pressure readings. Dinamap diastolic pressure readings were 5 mm Hg higher (95% confidence interval, -14 to 23 mm Hg) than the auscultatory Korotkoff phase V diastolic pressure readings. CONCLUSION: These findings preclude the interchange of readings by the 2 methods. Caution must be exercised in the diagnosis of hypertension when an automated device is used.     

The variability of arterial pressure measured by oscillometric methods in premature newborn infants

The variability of blood pressure measured by oscillometry and the validity of this technique were studied in premature infants. Thirty premature babies whose postnatal age was six days or more had their blood pressure measured 11 times over a twenty-minute period for three consecutive days. Movements were found to have a very substantial influence on results that could not be reliably compared with values obtained invasively. No consistent pattern of variations of oscillometric results obtained during the eleven measurements of use for recommending a specific measurement time was found. Diastolic blood pressure fell gradually over the three-day study period. The most reliable of the eleven daily values was the lowest value for which good correlations were found between the three study days; this lowest value was not influenced by neonatal or postnatal factors.     

Accuracy of the oscillometric method to measure blood pressure in children

OBJECTIVE: The aim of this study is to analyze the substitution of the standard auscultatory method by the oscillometric blood pressure monitor, independently of the validity of the intraarterial blood pressure measurement. The accuracy of the automatic oscillometric monitor was compared to the auscultatory mercury manometer blood pressure measurement in apparently healthy school age children. METHODS: A device able to perform 3 simultaneous readings are used: one reading by the monitor and the others by two "blind" observers. We studied 72 school age children with the following characteristics: mean age 9.5 (6.1-16.1) and 39 males (54.2%). RESULTS: The difference for the systolic and diastolic blood pressure obtained by the monitor was in average + 6.2 mmHg and + 10.0 mmHg, respectively, when compared to the observer's readings. There was neither a good correlation nor a good agreement between the two observers and the monitor in the blood pressure determination. CONCLUSIONS: We concluded that the substitution of the standard auscultatory method for the non-invasive oscillometric method to measure blood pressure in school age children can not be generally recommended.     

Comparison between oscillometric and invasive blood pressure measurements in critically ill premature infants

Aim: Blood pressure (BP) measurement techniques in neonates generally involve noninvasive measurements with a cuff (oscillometric) or invasive measurements through an arterial catheter. The aim of this study was to determine the reliability of the noninvasive oscillometric method in critically ill preterm infants when results were compared with the invasive technique. Method: Twenty‐seven premature infants with a mean birth weight of 1138 ± 552 g were enrolled in the prospective study. Invasive and noninvasive mean arterial pressure (MAP) levels were recorded simultaneously at each measurement in all patients. Low or lower range mean invasive MAP values (MAP ≤30) were evaluated separately as we aimed to assess the value of noninvasive measurements in hypotensive sick premature infants. Results: Totally, 431 paired BP measurements were taken during the first week of life. There was no statistically significant difference between invasive and noninvasive readings. However, noninvasive measurements were found significantly higher compared with invasive measurements in the presence of hypotension (p < 0.05). Conclusion: This study showed good agreement between oscillometric and invasive readings in critically ill premature infants, and further, comparable mean MAP values were found with the two methods. However, the accuracy of the oscillometric BP measurement technique fails in preterm infants with BP within the lower limits.     

Blood pressure in the neonate: three non-invasive oscillometric pressure monitors compared with invasively measured blood pressure

AIM: To compare blood pressure in neonates obtained from three different oscillometer blood pressure monitors (Dinamap, Criticare, Hewlett-Packard) with arterial blood pressure (Hewlett-Packard' invasive unit). STUDY DESIGN: A total of 32 randomized, non-invasive blood pressure series, each consisting of three measurements from each monitor, were obtained from 20 neonates (birthweight 531-4660 g). Each measurement was compared with the invasive pressure. RESULTS: Two factors appear to have a systematic effect on the difference between oscillometric and invasive pressure (the measurement deviance): the size of the infant, e.g., the arm circumference, and the monitor system. For small infants, the non-invasively measured value tends to be too high. The deviance is partly reversed for larger infants (dependency on size significant for mean and diastolic pressure, p < 0.001). The difference between monitor systems is clearly significant (p < 0.001). Hewlett-Packard gives the lowest pressure values for all pressures. Thus, Criticare and Dinamap tended to show values too high in the smallest infants, while Hewlett-Packard tended to give values too low in larger infants. Birthweight, present weight and arm circumference affected measurement deviance approximately equally strongly, while factors such as the infant's sex, need of breath support and umbilical or radial arterial line were non-significant. CONCLUSIONS: Blood pressure should preferably be measured invasively in severely ill neonates and preterm infants, being aware of pitfalls with measurements using different oscillometer monitors and the size/arm circumference of the infant.     

Prediction of arterial blood pressure in the premature neonate using the oscillometric method

The noninvasive oscillometric measurement of blood pressure (BP) in preterm neonates has become a common practice in intensive care nurseries. The method has gained acceptance primarily through its correlation with direct arterial measurement. In this study, the oscillometric method (using Dinamap 1846) was compared with direct intra-arterial BP monitoring in 15 preterm infants. The 95% prediction intervals for individual oscillometric measurements were wide, ranging from 17 mm Hg for the mean BP to 20 mm Hg for the systolic and diastolic BP. The oscillometric method also underestimated intra-arterial systolic and mean BP and overestimated diastolic BP. Caution must be used when oscillometrically measuring BP in premature neonates.     

Reference ranges for blood pressure in preschool Australians, obtained by oscillometry

OBJECTIVE: To derive reference centiles for blood pressure in children aged 1-6 years which seek to address shortcomings in available reference ranges. METHODS: Prospective cohort study of 2876 children in Perth, Western Australia, commenced in 1989 with serial blood pressure measurements through early childhood obtained by oscillometry under standardized conditions. RESULTS: Gender-specific reference centile charts for systolic and diastolic blood pressure, (i) across ages 1-6 years and (ii) across the range of corrected Body Mass Index values at ages 1, 3 and 6 years, were generated by fitting linear models with both fixed and random effects. CONCLUSIONS: Reference values for blood pressure for young children are of clinical use and may be of long-term predictive value.     

How to interpret blood pressure values obtained in children and adolescents

As soon as blood pressure (BP) values are available for a child or teenager, a multitude of questions arise. The values obtained need to be interpreted, validated, and made use of. Values measured in an individual can be interpreted only by comparison with the results of measurements performed using the same protocol in an adequate sample of subjects with similar life styles. The value of reference to stature rather than age has been well established. Studies of BP measured at rest are the most widely used. The validity of blood pressure values is dependent on measurement technique but is also related to the problem of intraindividual variability. To address this problem, blood pressure values have been measured not only at rest but also during standardized stimulation tests and throughout the 24-hour period (ambulatory BP measurements). Studies using these techniques in children and adolescents are still scant. Longitudinal studies of the mean-term and long-term reproducibility of these measurements are needed. Until results of such studies are available, blood pressure measurements in non-resting subjects will be mainly useful for evaluating patients with borderline BP values at rest and for monitoring the effect of therapy. The response to blood pressure values believed to be borderline should include evaluation of factors which influence BP values as well as of the other risk factors for cardiovascular disease. The predictive value of blood pressure levels is fairly poor in childhood. Correlation coefficients between values obtained five years apart approximate 0.25. These coefficients increase with age and finally level off at 0.4-0.5.(ABSTRACT TRUNCATED AT 250 WORDS)     

Arterial blood pressure in the very low birthweight neonate. Evaluation of an automatic oscillometric technique

The noninvasive oscillometric technique of arterial blood pressure determination was evaluated in fifteen very low birth weight neonates (less than 1,400 g). Measurement of invasive umbilical artery catheter pressure was used as a reference standard. By using a cuff width to arm circumference ratio of 0.33-0.42, mean blood pressure was overestimated by 6.2 (7.2) mmHg (mean and 1 SD), p less than 0.001. More accurate mean blood pressure measurements were recorded with a cuff width to arm circumference ratio of 0.44-0.55. Measurements of systolic and diastolic blood pressure showed similar results.     

Variability of blood pressure measured using an oscillometric method in children 4 to 48 months of age

The usual method of measuring arterial blood pressure cannot be used in children less than 4 years of age because of lack of cooperation. We investigated variations of blood pressure measured during 20 minutes by an oscillometric method (Dinamap) in 100 children aged 4 to 48 months and tried to come up with some recommendations for measuring and interpreting blood pressure. Serial blood pressure recordings showed poor reproducibility due to movements which are impossible to avoid and which account for wide variations. Because of this variability, a single measurement is inadequate and must be repeated. The average of repeated recordings does not seem to be a reliable parameter. We suggest that the lower measured value (minima) as the only parameter allowing us to track the progressive increase in blood pressure with age. The data probably explain the large discrepancies between published studies taking into account the use of different methods.     

Non-invasive oscillometric measurement of systolic,mean and diastolic blood pressure in infants with congenital heart defects after operation. A comparison with direct blood pressure measurements

The accuracy of indirect oscillometric blood pressure measurements has been evaluated in 32 infants up to 11 months of age undergoing heart surgery. In a number of 1029 simultaneous measurements the indirect blood pressure was compared with the direct value obtained from a radial artery catheter. Cuffs of different sizes were applied. The main results were as follows: (1) Regarding the ratio of cuff width to arm circumference, the best correlation between oscillometric and direct blood pressure measurements was obtained with a ratio of 0.38–0.41. (2) The value of indirect blood pressure measurements depends on the absolute height of the blood pressure. In low blood pressure there is a tendency to underestimate and in high blood pressure there is a tendency to overestimate by the oscillometric blood pressure measurement.By applying an appropriate cuff size and by using our diagrams it should be possible to derive a direct value for the blood pressure on the basis of indirect oscillometric blood pressure measurements.Abbreviations BP blood pressure - BPM blood pressure measurements - CW/ArmC cuff width to arm circumference ratio - DAP diastolic arterial pressure - MAP mean arterial pressure - SAP systolic arterial pressure - ME mean error - SD standard deviation Research fellow supported by the A. v. Humboldt Stiftung     

Catecholamine and blood pressure levels in paralysed preterm ventilated infants

The effect of pancuronium administration on catecholamine levels and blood pressure was investigated. Noradrenaline levels prior to paralysis amongst infants fighting the ventilator were high, but were significantly reduced following treatment with pancuronium. There was no significant change in either blood pressure or adrenaline levels. Increasing peak inspiratory pressure (approx. 4 cmH2O) immediately prior to paralysis effectively prevented the hypoventilation previously associated with the administration of the first dose of pancuronium.     

Systolic and diastolic blood pressure levels of healthy newborn infants

OBJECTIVE: To identify normative blood pressure (BP) levels for Brazilian newborn infants and to define a cut-off point for high systolic and diastolic BP in this population.METHODS: 634 healthy term neonates, aged 12 to 36 hours, who were born in the Instituto Materno Infantil de Pernambuco (IMIP) were included in this survey. An oscillometric method was used to acess the neonates BP. To identify high BP levels the Second Task Force definition was applied.RESULTS AND CONCLUSIONS: The normative BP values for the study sample was 82.0 -/+ 7.5 mmHg for systolic and 41.7 -/+ 5.8 mmHg for diastolic blood pressure. The cut-off points for high blood pressure were >/= 95 mmHg and >/= 52 mmHg for systolic and diastolic blood pressure respectively. These results are similar to those reported in other surveys done in other countries.     

Correlation of blood pressure with skinfold thickness and protein levels.

To plan prospective studies of obesity and hypertension, we measured skinfold thickness, weight, blood pressure, and protein fractions in 920 children who were divided according to age, sex, and race. Correlations between measurements were calculated within each of these groups. Children aged 10, 11, and 12 years had direct correlations between diastolic blood pressure and serum albumin level, but inverse correlations between diastolic blood pressure and alpha-globulin level as well as inverse correlations with alpha-globulin level. These correlations did not occur in similar children aged 8, 9, and 10. Although diastolic blood pressure correlated with skinfold thickness in all groups, there was no correlation between skinfold thickness and serum protein levels.     

Association of blood pressure, obesity and serum homocysteine levels in healthy children

AIM: Obesity, hypertension and total serum homocysteine levels are well-known risk factors for cardiovascular disease in adults. However, there is limited data on the relation of these risk factors in children. METHODS: Five hundred twenty-four healthy school children aged 6-15 years participated in the study. BMI were used to categorize our subjects in normal overweight and obese groups based on Internationally Obesity Task Force criteria. RESULTS: The prevalence of overweight and obesity was 21.1% and 8.4% for boys and 17.6% and 7.3% for girls, respectively. Diastolic blood pressure (DBP), systolic blood pressure (SBP) and waist circumference (WC) were significantly higher in overweight and obese group compared to normal ones, whereas for homocysteine levels no difference was observed. Based on the results derived from the multiple regression analysis, BMI was positively related to energy intake (beta=0.247, p<0.001) and WC (beta=0.014, p<0.001). Both SBP and DBP were positively related to age ([beta=0.251, p<0.001] and [beta=0.301, p<0.001, respectively]), and BMI ([beta=0.096, p<0.001] and [beta=0.022, p<0.001], respectively). CONCLUSION: The current study revealed an association of blood pressure and WC with overweight and obesity in children, and even though these children may not have increased homocysteine levels, they still have enough reasons to reduce weight in order to avoid cardiovascular disease in their life later on.