ABSTRACT & COMMENTARY

Synopsis: Ambulatory blood pressure monitoring can be accurately and conveniently carried out in young children, making it a potentially useful tool for the evaluation and treatment of hypertension.

Source: Gellermann J, et al. Twenty-four-hour ambulatory blood pressure monitoring in young children. Pediatr Nephrol 1997;11:707-710.
Gellermann and associates in germany studied a group of 61 healthy children and 40 children with previously diagnosed hypertension, renal disease, or both. Although Gellermann et al state that it was not their intent to develop normative data for young children (precluded by the small number of normal children studied), they determined systolic and diastolic means based on height, age, and time of day. During the day, the means were 110 ±5/100 ± 5 mmHg. Not surprisingly, during sleep (night and nap-time), the means were somewhat lower, 100 ± 5/58 ± 5 mmHg. Interestingly, they found that in five of 10 children with elevated blood pressure readings by casual determination, ambulatory blood pressure monitoring (ABPM) did not support a diagnosis of hypertension. At least 30 valid readings were required for inclusion, and many of the older children had more than 50 out of a potential total of 80. No significant differences were found with gender or with height (range, 100-130 cm).

COMMENT BY THOMAS KENNEDY, MD, FAAP

Many pediatricians may be unfamiliar with ABPM, although it has been studied and used in adult populations for more than 15 years and is now a routine part of the evaluation of adults suspected of having "white coat" hypertension and also for the initial diagnostic assessment of hypertension and response to therapy in many others. It is generally accepted that ABPM provides the strongest evidence of blood pressure determination of predicting cardiovascular end-organ damage. Although there are several published reports of ABPM in pediatric populations, until now, technical difficulties and the size of the monitor have limited studies to adolescents and older children. Furthermore, while it may be inferred that ABPM in hypertensive children may have the same clinical usefulness as in adults, the exact value of pediatric ABPM is still to be determined.

Procedurally, a blood pressure cuff is placed around an upper arm and the monitor is either carried on a shoulder strap or as a backpack. The cuff automatically inflates every 15 minutes during the day and every 30 minutes at night. Systolic and diastolic blood pressures as well as heart rate are recorded and stored by time and can be correlated with a diary to account for level of activity, sleep times, etc.

The current report established the feasibility of doing ABPM in young children and infants as young as 6 months old. The monitoring was reasonably well tolerated in their study groups, and the readings were consistent and accurate. Although one may argue that obtaining only 30 of a potential 80 blood pressure determinations in a 24-hour period leaves room for improvement, the mere fact that the investigators were able to have a group of toddlers tolerate the cuff is a considerable achievement. As technology improves, smaller and more accurate equipment may be reasonably expected. At present, the availability of ABPM equipment as used in this study is quite limited. Just as with Holter monitoring, clearer indications will have to be established, and certainly not every child with an elevated blood pressure determination should undergo ABPM. However, in very young children who become very upset and uncooperative at the first sight of a physician and have age-dependent elevation in their blood pressure, ABPM may be the ideal way to sort out situational vs. sustained hypertension.