Evaluation of an Automatic Oscillometric Method and of Various Cuffs for the Measurement of Arterial Pressure in the Neonate

Abstract

We compared simultaneous measurement of aortic, direct (Dir) and of indirect (Ind) systolic (S), mean (M) and diastolic (D) arterial pressure (AP) determined by an automatic oscillometric instrument (DINAMAP) in neonates with birthweight of 1000-3680 g. DINAMAP measurements were performed with cuffs of increasing width and length, recommended by the manufacturer for increasing arm circumference, and with a Standard sized cuff (2.5 X 15 cm), previously considered as suitable for neonates of any body size. In addition, we compared simultaneous measurements of Dir SAP and of Ind SAP determined by a Doppler technique and the Standard cuff. In DINAMAP SAP measurements with the Standard cuff, a statistically significant correlation between arm circumference and delta Ind-Dir SAP values (i.e. the difference between simultaneous Ind and Dir SAP measurements) was found. In DINAMAP MAP measurements with the cuff recommended for arm circumference, a statistically significant difference of the mean delta Ind-Dir MAP values was observed in infants whose arm was or was not completely encircled by the bladder of the cuff. In SAP as well as in MAP DINAMAP determinations, the overall error of measurement with the Standard cuff was smaller than with the recommended cuff. The Doppler method was found considerably more accurate than the DINAMAP method for the determination of SAP. In spite of these limitations, the DINAMAP method with the Standard cuff was considered to be reasonably accurate for the clinical determination of SAP and MAP, provided that several consecutive measurements are performed and averaged in order to minimize the error of measurement. When considering DAP measurements the error was so unacceptably high that the DINAMAP method cannot be recommended for clinical use. The need for a careful consideration of the cuff characteristics when evaluating new methods for the indirect measurement of AP in the neonate is emphasized.

Comparison of noninvasive and central arterial blood pressure measurements in ELBW infants

“…In previous studies, it has been observed that smaller cuff size has been associated with NBP and UAC measurement discrepancies for all blood pressure parameters. 8,11 Although we found a similar association, the overall predictive value of cuff size, even when combined with other variables, was low (r 2 <0.3). Cuff location was not associated with NBP and UAC measurement discrepancies, with a large majority of NBP measurements obtained from the lower limbs.…”

“…Previous studies included both term and a mixed population of small and large preterm infants. [6][7][8]12 In these studies, NBP measurements generally correlated with arterial measurements, with the correlation coefficients for mean blood pressure ranging from 0.67 to 0.92. In a cohort of 12 very-lowbirth-weight infants, NBP measurements overestimated blood pressure, especially at the lower end of the blood pressure range.…”

“…[2][3][4] However, it is unclear how NBP and arterial blood pressure measurements compare in preterm infants. [5][6][7][8][9][10][11][12] Data on the correlation between NBP and arterial measurements in extremely low-birth-weight (ELBW) infants are particularly lacking. One small study, evaluating systolic NBP and arterial blood pressure measurements, showed discrepant NBP and arterial measurements in infants who weighed <750 g. 13 The aim of this study was to compare measurements of systolic, mean and diastolic blood pressures obtained using noninvasive means with measurements procured from a central arterial catheter in newborn ELBW infants.…”

Evolution of systemic arterial blood pressure during neonatal period in term newborns adequate for gestacional age

“…Quando as medidas são realizadas em condições inapropriadas, o resultado pode ser 20 a 30% maior que o valor normal. Se isso ocorrer, recomenda-se repetir a avaliação e, se possível, utilizar a média de 3 ou mais medidas 4,6 . Deve-se utilizar também um manguito de tamanho adequado, já que manguitos menores que os recomendados podem determinar valores falsamente elevados e vice-versa 1,4,5,7,21 .…”

“…No início deste século, Balard já citava que a oscilometria era o único método que possibilitava a determinação da PA em crianças pequenas 4 . Atualmente, está comprovada a correlação entre a variação da PA determinada pela técnica de oscilometria e aquela obtida por cateter intra-arterial 1,[4][5][6][7] . Sendo assim, a oscilometria constitui um instrumento de grande utilidade para a monitorização não-invasiva de pacientes graves e para determinação da PA no exame detalhado do RN.…”