Central blood pressure in children and adolescents: non-invasive development and testing of novel transfer functions.

Central blood pressure can be estimated from peripheral pulses in adults using generalised transfer functions (TF). We sought to create and test age-specific non-invasively developed TFs in children, with comparison to a pre-existing adult TF. We studied healthy children from two sites at two time points, 8 and 14 years of age, split by site into development and validation groups. Radial and carotid pressure waveforms were obtained by applanation tonometry. Central systolic pressure was derived from carotid waveforms calibrated to brachial mean and diastolic pressures. Age-specific TFs created in the development groups (n=50) were tested in the validation groups aged 8 (n=137) and 14 years (n=85). At 8 years of age, the age-specific TF estimated 82, 99 and 100% of central systolic pressure values within 5, 10 and 15 mm Hg of their measured values, respectively. This TF overestimated central systolic pressure by 2.2 (s.d. 3.7) mm Hg, compared to being underestimated by 5.6 (s.d. 3.9) mm Hg with the adult TF. At 14 years of age, the age-specific TF estimated 60, 87 and 95% of values within 5, 10 and 15 mm Hg of their measured values, respectively. This TF underestimated central systolic pressure by 0.5 (s.d. 6.7) mm Hg, while the adult TF underestimated it by 6.8 (s.d. 6.0) mm Hg. In conclusion, age-specific TFs more accurately predict central systolic pressure measured at the carotid artery in children than an existing adult TF.

The effect of dairy consumption on blood pressure in mid-childhood: CAPS cohort study.

BACKGROUND/OBJECTIVES: It has been postulated that a higher dairy consumption may affect blood pressure regulation. The aim of this study was to examine the association between dairy consumption and blood pressure in mid-childhood. SUBJECTS/METHODS: Subjects (n = 335) were participants of a birth cohort at high risk of asthma with information on diet at 18 months and blood pressure at 8 years. Multivariate analyses were used to assess the association of dairy consumption (serves) and micronutrient intakes (mg). In a subgroup of children (n = 201), dietary intake was also measured at approximately 9 years. RESULTS: Children in the highest quintile of dairy consumption at 18 months had lower systolic blood pressure (SBP) and diastolic blood pressure (DBP) at 8 years (2.5 mm Hg, P=0.046 and 1.9 mm Hg, P = 0.047, respectively) than those in the lowest quintiles. SBP was lowest among children in the highest quintiles of calcium, magnesium and potassium intakes. Significant negative linear trends were observed between SBP and intakes of dairy serves, calcium, magnesium and potassium. Furthermore, SBP and DBP were lowest in the group of children that consumed at least two dairy serves at both 18 months and the follow-up dietary data collection at 9 years, compared with all other children (SBP 98.7 vs 101.0 mm Hg, P = 0.07; and DBP 56.5 vs 59.3 mm Hg, P = 0.006, respectively). CONCLUSION: These results are consistent with a protective effect of dairy consumption in childhood on blood pressure at age 8 years.

Hydromyelia and Chiari malformation in children and adolescents.

A series of 24 patients with Chiari malformation and hydromyelia, treated at the Prince of Wales Children's Hospital between 1975 and 1991, is reviewed. The age range of these patients was 3 to 19 years. Eleven had a Chiari 1 malformation and 13 had a Chiari 2 malformation. The follow-up period ranged from 6 months to 16 years with a mean of 5 years. Twenty-one patients had posterior fossa decompression procedures as the primary treatment, with or without plugging of the central canal at the obex. Forty-five per cent of the Chiari 1 patients and 62% of the Chiari 2 patients showed sustained neurological improvement. A further 36% of the Chiari 1 patients and 15% of the Chiari 2 patients had their neurological deficits stabilised. Following operation, sustained radiological collapse of the cavity occurred in 9 out of the 11 cases of Chiari 1 malformation. The follow-up radiology in the Chiari 2 patients has been incomplete. Complications following posterior fossa procedures with plugging of the central canal were transient and there has not been long-term morbidity. Posterior fossa decompression, fourth ventriculostomy, obex plugging and dural grafting is recommended in those cases where the surgical anatomy allows dissection of the tonsils from the brainstem. Plugging of the central canal at the obex is of value if the muscle plug is firmly secured.