Cateteres venosos totalmente implantáveis: histórico, técnica de implante e complicações / Totally implantable venous catheters: history, implantation technique and complications

O acesso ao sistema venoso, seja para coleta de amostras de sangue ou para infusão de soluções, é de vital importância para o diagnóstico e tratamento de pacientes com as mais variadas condições clínicas. Desde que Harvey, em 1616, descreveu o sistema circulatório a partir de estudos em animais e que Sir Christopher Wren, 4 décadas depois, realizou a primeira infusão endovenosa em seres vivos, a evolução na técnica de acesso e nos dispositivos para infusão tem sido constante. Merece destaque a criação dos cateteres de longa duração na década de 1970, em especial os totalmente implantáveis, que revolucionaram o tratamento do câncer, aumentando a segurança e o conforto dos pacientes oncológicos. Este artigo tem como objetivo a revisão de dados históricos relativos ao acesso vascular e a discussão da técnica de implante e das principais complicações associadas ao procedimento de colocação e ao uso dos cateteres totalmente implantáveis

Access to the venous system is of vital importance for diagnosis and treatment of patients with the most varied range of clinical conditions, whether for taking blood samples or for infusion of solutions. In 1616, Harvey described the circulatory system on the basis of studies in animals and 4 decades later Sir Christopher Wren conducted the first intravenous infusions in living beings. Since then there has been constant evolution in access technique and infusion devices. Of particular note is the creation of long-term catheters in the 1970s, particularly totally implantable devices, which revolutionized cancer treatment, increasing both safety and comfort for oncology patients. The objectives of this article are to review historical data on vascular access and discuss the implantation technique and the main complications associated with procedures for placement and use of totally implantable venous access devices

Pressão venosa central em cateter femoral: correlação com acesso superior após cirurgia cardíaca / Central venous pressure in femoral catheter: correlation with superior approach after heart surgery

OBJETIVO: É comum a obtenção de acesso venoso femoral em pacientes submetidos a cirurgia cardíaca em associação ou como alternativa ao acesso superior (veia jugular interna ou veia subclávia). O objetivo deste estudo foi comparar as medidas de pressão venosa central (PVC) em dois sítios diferentes (superior vs. femoral). MÉTODOS: Estudo prospectivo e aberto com 60 pacientes submetidos a cirurgia cardíaca no período de julho a novembro de 2006. Foram obtidas três medidas de cada paciente em cada sítio (admissão, 6 e 12 horas após a cirurgia) em duas inclinações diferentes da cabeceira do leito (zero e 30 graus), totalizando 720 medidas. RESULTADOS: Cinqüenta e cinco por cento dos pacientes foram submetidos a revascularização do miocárdio, 38 por cento a cirurgia valvar e 7 por cento a outras cirurgias. A média de PVC ± desvio padrão (DP) medida no acesso superior foi de 13,0 ± 5,5 mmHg (zero grau) e 13,3 ± 6,1 mmHg (30 graus), enquanto que as medidas no acesso inferior foram 11,1 ± 4,9 mmHg (zero grau) e 13,7 ± 4,6 mmHg (30 graus). A correlação linear (r) entre as medidas nos dois sítios foi de 0,66 (zero grau) e 0,53 (30 graus), ambas com p < 0,0001. CONCLUSÃO: A PVC pode ser medida com acurácia no acesso venoso femoral no pós-operatório imediato de cirurgia cardíaca, com melhor correlação linear obtida com as medidas feitas com a cabeceira do leito posicionada em zero grau.

OBJECTIVE: It is common to obtain femoral venous approach in patients undergoing combined heart surgery or as an alternative to superior approach (internal jugular vein or subclavian vein). The aim of this study was to compare the measures of central venous pressure (CVP) at two different sites (superior versus femoral). METHODS: We prospectively and openly allocated 60 patients who underwent heart surgery between July from November 2006. Three measures were obtained from each patient at each site (admission, 6 and 12 hours after surgery) in two different inclinations of the headboard (zero and 30 degrees) totaling 720 measures. RESULTS: Fifty five percent of patients who underwent coronary artery bypass grafting, 38 percent heart valve surgery and 7 percent other surgeries. The mean of CVP ± standard deviation (SD) measured in superior approach was 13.0 ± 5.5 mmHg (zero degree) and 13.3 ± 6.1 mmHg (30 degrees) while the measures in inferior approach were 11.1 ± 4.9 mmHg (zero degree) and 13.7 ± 4.6 mmHg (30 degrees). The linear correlation (r) between the measures in both sites was 0.66 (zero degree) and 0.53 (30 degrees), both with p value<0.0001. CONCLUSION: The CVP can be measured with accuracy in the femoral venous approach in the immediate postoperative period of heart surgery with better linear correlation obtained with the measures made with the headboard positioned at zero degree.

Regional differences in veins wall viscosity, compliance. energetics and damping: analysis of the pressure-diameter relationship during cyclical overloads

Background: The characterization of the dynamic process of veins walls is essential to understand venous functioning under normal and pathological conditions. However, little work has been done on dynamic venous properties. Aim: To characterize vein compliance (C), viscosity (η), peak-strain (W St) and dissipated (W D) energy, damping (ξ), and their regional differences in order to evalúate their role in venous functioning during volume-pressure overloads. Methods: In a mock circulation, pressure (P) and diameter (D) of different veins (anterior cava, jugular and femoral; from 7 sheep), were registered during cyclical volume-pressure pulses. From the P-D relationship, C, W St and ξ (at low and high P-D leveis), η and W D were calculated. Resulls: For each vein there were P-dependent differences in biomechanical, energetics, and damping capability. There were regional-differences in C, η), W St and W D (p<0.05), but not in ξ. Conclusión: The regional-dependent differences in dynamics and energetics, and regional-similitude in damping could be important to ensure venous functioning during acute overloads. The lower C and higher W St and W D found in back-limb veins (femoral), commonly submitted to high volume-pressure loads (i.e. during walking), could be considered relevant to ensure adequate venous system functionality and venous wall protection simultaneously.

Taquicardia auricular ectópica: fulguración exitosa con radiofrecuencia / Ectopic atrial tachycardia: successfully fulguration with radiofrequency

La taquicardia auricular es una causa de taquicardia paroxística supraventricular que puede originarse en relación a un circuito de reentrada intraauricular o por la existencia de uno o múltiples focos de automatismo anormal. Esta última forma de taquicardia se denomina como taquicardia auricular ectópica (TAE) y se caracteriza porque suele ser resistente a tratamiento antirrítmico y porque en caso de tener carácter incesante puede llevar a insuficiencia cardíaca. En los últimos años se han desarrollado diversas alternativas de tratamiento no farmacológico. En la presente publicación presentamos el caso clínico de una mujer con TAE derecha que fue fulgurada con radiofrecuencia en forma exitosa

Evaluation of venous valvular function of the lower limb by duplex ultrasonography

The duration of reverse flow after release of manual calf compression was measured in the common femoral, long saphenous, popliteal and short saphenous veins in 27 patients with venous disease of the lower limb by duplex ultrasonography. Fifteen controls without venous disease were assessed also. Before undertaking the study, the reproducibility of the technique was evaluated in 6 subjects by repeating the examination over 3 consecutive days, the coefficient of variation of the test was 7.3%. The 95% confidence interval [c.i.] of the median [0.16 s] of all measurements in the normal limbs was 1.12 - 0.18 s. In limbs with clinical evidence of venous disease at least one of the sites examined was found to have reverse flow longer than 0.5 s. These data suggested that the measurement of reverse flow after release of manual calf compression is a reproducible technique. While, the method records some reverse flow in normal veins, its duration is unlikely to exceed 0.5 s, significant reflux is therefore defined as reverse flow exceeding 0.5 s