Age-related differences in intracranial pressure and cerebral perfusion pressure in the first 6 hours of monitoring after children’s head injury: association with outcome

Objectives Severe head injury in childhood is associated with considerable mortality and morbidity. In this study we determined age-related differences in the relationship between outcome and intracranial pressure (ICP) and cerebral perfusion pressure (CPP) in the first 6 h of monitoring in a large cohort of head-injured children.Methods Two hundred and thirty-five head-injured children (admitted to five UK hospitals over a 15-year period) in whom intracranial pressure monitoring was clinically indicated were studied.Results Patients were divided into three age groups (2–6, 7–10 and 11–16 years). The sensitivity of ICP and CPP were similar. Differences were found in the specificity of ICP and CPP for each group and these were more marked for CPP. For a specificity of 50% the pressures were 53, 63 and 66 mmHg for the three age groups.Conclusions There are age-related differences in the specificity of intracranial pressure and cerebral perfusion pressure in relation to outcome. These differences may be important in the clinical management of head-injured children. Thus cerebral perfusion pressures of 53, 63 and 66 mmHg should be the minimum to strive for in these three age groups respectively.     

Peripheral blood pressure measurement is as good as applanation tonometry at predicting ascending aortic blood pressure

BACKGROUND: The Sphygmocor system purports to be able to assess ascending aortic blood pressure using a transfer function. It has been shown to be accurate when data obtained invasively are used, but has not been tested prospectively using data obtained non-invasively. OBJECTIVE: To investigate the accuracy of this equipment when measurements are obtained non-invasively, as would normally be the case in the clinic setting. DESIGN AND METHODS: The study was observational. Ascending aortic pressure measurements were taken simultaneously with radial artery pressure wave recordings for estimation of ascending aortic blood pressure, in 28 patients undergoing diagnostic cardiac catheterization. RESULTS: The transfer function in the Sphygmocor system significantly underestimated invasively measured systolic blood pressure [mean -7.23 +/- 10.07 mmHg; 95% confidence interval (CI) -3.3 to -11.14 mmHg, P = 0.001] and significantly overestimated invasively measured diastolic blood pressure (mean 12.20 +/- 7.14 mmHg; 95% CI 9.43 to 14.97 mmHg, P <0.001). Oscillometrically measured brachial systolic blood pressure was not significantly different from that measured invasively in the ascending aorta (mean 3.36 +/- 10.47 mmHg; 95% CI -0.69 to 7.43 mmHg, P = 0.1), but oscillometric measurement of brachial diastolic blood pressure gave a significant overestimation of that measured invasively (mean 11.70 +/- 7.18 mmHg; 95% CI 8.91 to 14.49 mmHg, P <0.001).CONCLUSIONS The transfer function in the Sphygmocor system is no better at estimating ascending aortic blood pressure than are standard peripheral blood pressure measurements. It may be necessary to derive a new transfer system that is based on data that are acquired entirely non-invasively.     

3-(2-aminoalkyl)-1-(2,6-difluorobenzyl)-5- (2-fluoro-3-methoxyphenyl)-6-methyl-uracils as orally bioavailable antagonists of the human gonadotropin releasing hormone receptor

Uracils possessing N-3 side chains derived from various amino alcohols were designed and synthesized as potent human gonadotropin releasing hormone receptor antagonists. The compounds herein presented displayed superior metabolic stability than their predecessor molecules. Selected compounds from this series featured good oral bioavailability in mice and cynomolgus monkeys.     

Cardiovascular autonomic function in patients with hemodynamic instability at induction of capnoperitoneum: a case–control study

Background This study hypothesized that patients in whom bradycardia and hypotension develop with induction of positive-pressure capnoperitoneum have an underlying autonomic cardiovascular dysfunction.Methods A case–control study was conducted to examine the baseline autonomic function of patients in whom bradycardia and hypotension develop with induction of positive-pressure capnoperitoneum. The control group consisted of patients who maintained normal cardiac rhythm and blood pressure during the same procedure. Two groups of tests were performed: bedside stress tests of cardiovascular autonomic function (response graded 1 (normal) to 4 (severely abnormal) and heart rate variability analysis (spectral and time domain components).Results The study evaluated 6 patients in the bradycardia group and 10 in the control group. The group in whom bradycardia had developed scored significantly worse on the bedside stress tests than the control group (for grades I to IV: ² = 6.5, p = 0.022; for trend: ² = 5.6, p = 0.018). In contrast, both groups had similar baseline autonomic tone, as measured by heart rate variability.Conclusions Patients in whom bradycardia and hypotension develop with induction of positive-pressure capnoperitoneum have cardiovascular autonomic dysfunction, which is identifiable by bedside stress tests of autonomic function.     

American Indian internet cigarette sales: another avenue for selling tobacco products

A study conducted by the University of Minnesota found that cigarettes can be purchased on American Indian-owned Internet sites for about one fifth of the price at grocery stores, making this a more convenient, lower-priced, and appealing method of purchasing cigarettes. Researchers and educators are challenged to address this new marketing ploy and to discover ways to curb rising smoking rates in American Indian communities.     

The neurohormonal natural history of essential hypertension: towards primary or tertiary aldosteronism?

Use of the aldosterone-to-renin ratio has controversially suggested that approximately 10% of hypertensives have primary aldosteronism, and most of these individuals are thought to have idiopathic hyperaldosteronism. The usual renin-angiotensin system control is intact in these individuals and is similar to that in low renin and essential hypertensives, differing only in the degree of sensitivity. There is recent evidence suggesting that hyperaldosteronism relates to aldosterone synthase genetic polymorphism, and also that increased angiotensin II stimulation of the adrenal glands appears to paradoxically upregulate the receptors increasing angiotensin II sensitivity. Taken together, the possibility arises that, in susceptible hypertensives, hyperaldosteronism could be acquired. Indeed, it is well known that renin-driven renovascular hypertension is associated with the development of hyperaldosteronism. Hypothetically, within the wider hypertensive population, these findings set the scene that angiotensin II adrenal sensitivity increases over time until the secretion of aldosterone becomes "autonomous" and hence "tertiary" aldosteronism in a significant proportion of hypertensives.