[Automatic measurement of arterial pressure]. / Medição automática da pressão arterial.

Whenever we have a new technique for the measurement of Blood Pressure (BP), variations to standard devices should be expected. Recent guidelines for measurement and validation of automatic devices by Scientific Societies should be followed if doctors want to improve the accuracy of readings, avoiding mistakes in the diagnosis and monitoring of hypertension. To characterize the variability and reproducibility of the DINAMAP (Dynamic Automatic Mean Arterial Pressure), a random comparison with two observers (A; B) between this device and the sphygmomanometer was performed in a group of 80 patients with different pathologies. To evaluate the variability and reproducibility in the same person we analysed as well the mean variation in a setting of successive readings in 3 persons. The global correlation was good for both systolic (r = 0.9) and diastolic pressures. The behaviour of the DINAMAP for different pressure levels was obtained by the regression analyses of the pressures differences between both devices. The best correlation is found around the 140 mmHg measurements, pressures above or under this level are respectively underestimated and undervalued. We discuss the needs of a standard statistical methodology with physiological meaning for the analysis which enables to understand the multiple variations that doctors can find when performing the comparison tests.

[Central and peripheral vascular resistance]. / Resistência vascular central e periférica.

Better knowledge of organ damage produced by arterial hypertension in multiple conditions led to the conclusion that blood pressure readings (the values) were not the only determinant but instead a whole range of factors dependent on the arterial wall characteristics. The concept of windkessel in relation to the stiffness and the compliance of the arterial system, the impedance at any given point evoking different volume/pressure/flow relationship (with pressure tracings) rekindled interest in this matter, leading to a more adjusted model. Invasive (micromanometers) and non-invasive methods (such as the echodoppler) are the investigation and clinical support of this new interest in an old idea developed before the epidemiological period of arterial hypertension study. The similitude between ageing and hypertension, the contraposition that is seen in youngsters, and other metabolic alterations test this model of winkessel.

[Ambulatory monitoring of blood pressure. Validation of a method]. / Medicação ambulatória da pressão arterial. validação do método.

Before the routine use of our ambulatory blood pressure (ABP) device, we did the correlation analysis of 153 pairs of blood pressure measurements within the ABP and gold-standard sphygmomanometer. We got a good correlation but a systematic statistical error about less 7 mmHg on systolic measurement and 11 mmHg on diastolic measurement by the ABP device. The different qualities found among the devices that we have in the market, lead to the proposal of protocols of validation in the premarketing and periodic quality assessment by the clinics.

[Aneurysm of the abdominal aorta. Is arterial hypertension a risk factor?]. / Aneurisma da aorta abdominal. Hipertensão arterial como factor de risco?

OBJECTIVE: the purpose of this study was to measure ecographically and ascertain the characteristics of the abdominal aorta in a sample of the male population over sixty years, and try to correlate the findings with some so-called "risk factors" most currently quoted in the medical press, such as arterial hypertension, diabetes mellitus, tobacco consumption and coronary or cerebrovascular diseases. MATERIAL AND METHODS: this is a preliminary note of the results obtained in the first forty patients in a prospective study (still ongoing). They were choose randomly from all those admitted to the general medicine ward of Medicine I Hosp. St. Maria or attended at the Medicine or Cardiology/Hypertension outpatient clinics at the same hospital. Pearson's linear correlation, Student's t test for not paired samples and chi-square tests were used to analyze the results. MEASUREMENTS AND MAIN RESULTS: the medium value obtained for the abdominal aorta diameter (daa) was 28.8 mm (SD. +/- 3.6). In this sample there was no correlation between the age and daa (r:0.03), nor any statistical difference (chi-square) in the daa between the subgroups creating regarding the existence of hypertension no hypertension, active smoking/no smoking habits, or the association of all these so-called risk factors added to diabetes as opposed to their absence (the number of patients is still insufficient to reach statistical significance). CONCLUSIONS: in this study no risk factor/marker of the aneurysm of the abdominal aorta was so far detected in a population of aged male patients, but in some groups (as in the association of multiple factors) the number of patients was insufficient to reach any significant statistical conclusion.