A importância das medidas de pressão arterial e da velocidade da onda de pulso no desenvolvimento da hipertrofia ventricular esquerda e no espessamento médio-intimal de carótidas em pacientes idosos / The importance of arterialpressure measurement and of pulse wave velocity n the development ao left ventricular hypertrophy and in carotid intima-media thickening in elderly patients

Objetivo: O objetivo deste estudo foi avaliar três grupos de indivíduos idosos, estratifcados segundo a MAPA em: normotenso (Grupo 1);provavelmente hipertenso sistólico isolado (Grupo II); e provavelmente hipertenso sisto-diastólico (Grupo III), na tentativa de identificar, entre as variáveis estudadas, aquelas que se correlacionavam com o determinismo das LOA definidas como HVE e ESPCED.Métodos: foram selecionados 89 indivíduos que se submeteram a exames laboratoriais, ao ECG com o objetivo de se excluir doença coronariana evidente, e à MAPA para a estratificação dos grupos. As variáveis analisadas para essas correlações compreenderam as medidas de PA casual e ambulatorial; as medidas de ESPCE e/ou ESPCD, através de ultr-som de carótidas; as medidas de MVE e IMVE, através da ecocardiografia; e medidas da VOP.Resultados: Os três grupos apresentaram distribuição semelhante em relação à idade, ao sexo, e aos índices antropométricos, bem como em relação à análise das médias dos parâmetros bioquímicos. Demostrou-se distribuição similar de ESPCED e de HVE, nos dois grupos de hipertensos, porém, com valores estatisticamente superiores em relação ao grupo de normotensos. As variáveis analisadas com significado estatístico e correlação positiva com a MVE foram: PAS24h, PP24h, PASVIG, PASSONO, PADSONO, e VOP; e a de correlação negativa foi a DESCPAS. As de correlação positiva com o ESPCED foram: PAS24h, PP24h, VS24h, PASVIG, PASSONO e VOP; e as de correlação negativa foram: DESCPAS e DESCPAD. Analisando o determinismo das LOA, observa-se que a PAS24h foi a única variável que manteve associação com a HVE(p igual0,0161), e a VOP com o ESPCED(p igual 0,033).Conclusões: demonstrou-se que a análise das variáveis de PA e VOP são de extrema validade na investigação de LOA em indivíduos idosos

Pulse dispersion due to atrial fibrillation causes arterial thrombosis in a rabbit experimental model.

Thrombosis associated with atrial fibrillation (AF) is usually caused by a left atrial (LA) thrombus, but it is not always detected. The present study was based on the hypothesis that abnormalities in peripheral artery are responsible for the ischemic stroke associated with AF. Peripheral arterial coagulability was investigated in a rabbit experimental model in which AF was induced by high-frequency stimulation of the right atrium, creating stenosis of the carotid artery together with endothelial damage. The rabbits were classified into 4 groups: (i) sinus rhythm only (group 1), (ii) sinus rhythm after 6 h of pacing (group 2), (iii) short AF (continuous pacing for 5 min; group 3) and (iv) long AF (continuous pacing for 6 h: group 4). The carotid blood flow developed a typical pattern, called cyclic flow reductions (CFRs), the frequency of which (CFRF) was 18.59+/-2.85 in AF (group 3+4) compared with 14.46+/-2.1 in sinus rhythm (group 1+2) (p<0.0005). Among the groups with AF, correlation analysis showed an association between CFRF and pulse dispersion (p<0.02, r=0.58). This study suggests that the distinctive hemodynamic effects with AF, in particular pulse dispersion, substantively influence thrombus formation on injured vascular endothelium.

Randomized, double-blind trial of 1- versus 4-hour amphotericin B infusion durations.

We conducted a randomized, double-blind trial of 1- versus 4-h infusions of amphotericin B to determine whether there was any difference in infusion-related toxicity. A total of 128 maintenance infusions in 12 patients were studied; 62 were randomized to 1-h infusions (group A) and 66 were randomized to 4-h infusions (group B). We found no significant differences between patients in groups A and B in mean temperature, pulse, or systolic or diastolic blood pressure measured during the infusions. At a significant level of 0.05, the power to detect a mean difference in temperature of 2 degrees C, a pulse difference of 20 beats per min, a decrease in diastolic blood pressure of 10 mm Hg, or a decrease in systolic blood pressure of 20 mm Hg was 0.95. Rigors and chills were noted in 15 of 62 (24.1%) infusions in group A patients and 12 of 66 (18.1%) infusions in group B patients (P = 0.40). Meperidine was required because of severe persistent rigors in 6 of 62 (9.6%) infusions in group A patients and 6 of 66 (8.9%) infusions in group B patients (P = 0.91). An increase in temperature was noted in five (8%) of the group A infusions and seven (10.6%) of the group B infusions (P = 0.63). The mean time to onset of rigors, an increase in temperature, and an increase in pulse occurred significantly earlier in group A than in group B patients (P = 0.02 for all comparisons). We conclude that there is no difference in the incidence or severity of the infusion-related toxicity of amphotericin B with a 1-h infusion rate compared with a 4-h infusion rate. However, the onset of infusion-related toxicity occurs significantly earlier with a 1-h infusion.

Comparison of respiratory effects of two cardioselective beta-blockers, celiprolol and atenolol, in asthmatics with mild to moderate hypertension.

The effects of two cardioselective beta-adrenergic blocking agents--celiprolol (claimed to have bronchodilator properties) and atenolol (without such claims)--on respiratory function and control of asthma were studied in ten asthmatic patients with mild to moderate essential hypertension. Following a beta-2 agonist-free period of ten hours, administration of 100 mg of atenolol was associated with bronchoconstriction (p less than 0.05), whereas 400 mg of celiprolol was not. Responsiveness to beta-2 agonist therapy was retained with both agents (p less than 0.05). Day-to-day asthma control, interpreted from patient recordings of peak flow, inhaler use and symptom scores, were all no different on either agent from placebo. When given acutely, celiprolol appeared to have acute bronchosparing properties, possibly providing a greater margin of respiratory safety than atenolol.

Influence of hydrocortisone succinate on intrarenal accumulation of gentamicin in endotoxemic rats.

Gentamicin is a commonly used antibiotic in the treatment of gram-negative infections including septicemia and pyelonephritis. Bacterial endotoxin is liberated during antibiotic therapy and may lead to endotoxemic shock. Steroids such as hydrocortisone are generally recommended in the treatment of endotoxemic shock. There are very limited data on the influence of endotoxin or corticosteroids on the pharmacology of antibiotics, especially aminoglycosides, which are nephrotoxic. We studied the influence of both Escherichia coli endotoxin and hydrocortisone succinate on the renal uptake of gentamicin in rats. Animals were injected intravenously with endotoxin (0.25 mg/kg) and/or hydrocortisone (25 mg/kg) plus gentamicin (10 mg/kg). Gentamicin levels in the serum and renal parenchyma as well as renal function and histology were evaluated. Both endotoxin and hydrocortisone given alone increased the concentration of gentamicin in the renal cortex (P less than 0.05). Normal values in serum were observed in all groups at most time intervals. When administered together, endotoxin and hydrocortisone did not potentiate each other. The combination of endotoxin and hydrocortisone gave significantly higher levels of gentamicin than endotoxin or hydrocortisone alone when endotoxin was injected 3 h before hydrocortisone (P less than 0.05). Blood pressure and cardiac frequency were normal when gentamicin was given. Endotoxin alone slightly decreased the glomerular filtration rate, and hydrocortisone alone slightly modified renal plasma flow. The combination of both drugs did not significantly affect renal function. No histological lesion was noted on light microscopy in animals receiving endotoxin. Competitive or synergistic activity of endotoxin, gentamicin, and hydrocortisone at the cellular level, especially on membranes or lysosomes, might explain in part our observation on the renal uptake of gentamicin. By increasing the total amount of drug within the kidney, endotoxin and hydrocortisone might increase the risk of nephrotoxicity associated with aminoglycosides.

Anesthetic problems with aspirin-intolerant patients.

Sixty-seven aspirin-sensitive asthmatic patients underwent a total of 89 operative procedures. Wheezing with induction, intraoperative tachycardia and arrhythmias, and postoperative wheezing were the major problems in their anesthetic course. Wheezing was encountered despite various induction technics. Preoperative steroids, aminophylline, and ephedrine appeared necessary for surgical preparation, but the presence of aminophylline and ephedrine predisposed to tachycardia under anesthesia. The appearance of mild preoperative wheezing allows the prediction of postoperative wheezing in a significant number of patients.