Fluid volume kinetics of dilutional hyponatremia; a shock syndrome revisited

OBJECTIVE: To evaluate whether the pathophysiology of shock syndromes can be better understood by comparing central hemodynamics with kinetic data on fluid and electrolyte shifts. METHODS: We studied the dilutional hyponatremic shock that developed in response to overhydration with electrolyte-free irrigating fluid - the so-called ‘transurethral resection syndrome' - by comparing cardiac output, arterial pressures, and volume kinetic parameters in 17 pigs that were administered 150 ml/kg of either 1.5% glycine or 5% mannitol by intravenous infusion over 90 minutes. RESULTS: Natriuresis appeared to be the key factor promoting hypovolemic hypotension 15-20 minutes after fluid administration ended. Excessive sodium excretion, due to osmotic diuresis caused by the irrigant solutes, was associated with high estimates of the elimination rate constant (k10) and low or negative estimates of the rate constant describing re-distribution of fluid to the plasma after translocation to the interstitium (k21). These characteristics indicated a high urinary flow rate and the development of peripheral edema at the expense of plasma volume and were correlated with reductions in cardiac output. The same general effects of natriuresis were observed for both irrigating solutions, although the volume of infused 1.5% glycine had a higher tendency to enter the intracellular fluid space. CONCLUSION: Comparisons between hemodynamics and fluid turnover showed a likely sequence of events that led to hypovolemia despite intravenous administration of large amounts of fluid. .

Hemorrhagic shock influence on colonic anastomoses in rats: evaluation of rupture by liquid distension resistance test / Influência do choque hemorrágico na anastomose de cólon em ratos: avaliação com teste de resistência à pressão de ruptura

PURPOSE: To evaluate the effect of hemorrhagic shock in colonic anastomoses in rats, with a rupture by liquid distension resistance test. METHODS: Wistar lineage rats, averaging 90 days old and weighing from 310 to 380 grams were divided into two groups. In the first group (G1), 10 animals were submitted to colonic anastomoses in normovolemic terms and the second group (G2), of 10 animals, was submitted to colonic anastomoses in hypovolemic conditions. The shock was caused by half milliliter of blood withdrawn, every two minutes, until the value of average 50mmHg arterial pressure or a total volume corresponding 30 percent withdrawal of volemia was reached. Serum lactate dosages were carried out at the beginning and end of the procedure. The average serum lactate values at the end of the surgery were 1.91 mmol/l in G1 group and 3.69 mmol/l in G2 group (p<0.05). On the fifth postoperative day, the animals were euthanized. The anastomoses were evaluated with a rupture by liquid distension resistance test. RESULTS: In G1, the average value of colonic rupture was 160.7 mmHg whereas in G2 it was 152.1mmHg (p>0.05). CONCLUSION: Hemorrhagic shock, under the established conditions of this study, had no influence on colonic anastomoses in rats evaluated with the rupture by liquid distention resistance test.

OBJETIVO: Avaliar o efeito do choque hemorrágico em anastomoses de cólon em ratos, com teste de ruptura à distensão por líquido. MÉTODOS: Foram utilizados ratos da linhagem Wistar, com idade aproximada de 90 dias e peso variando de 310 gramas a 380 gramas. Os animais foram divididos em dois grupos, sendo o grupo G1, composto por 10 animais submetidos à anastomose de cólon em condições de normovolemia e o grupo G2, composto por 10 animais submetidos à anastomose de cólon em condições de hipovolemia. O choque foi instalado através da retirada de meio mililitro de sangue a cada dois minutos, até que se atingissem valores de pressão arterial média (PAM) de 50mmHg ou volume total de retirada correspondente a 30 por cento da volemia. Foram realizadas dosagens séricas de lactato (mmol/l) no início do procedimento e ao término do mesmo. Os valores séricos médios de lactato ao término da cirurgia foram de 1,91 mmMol/l no grupo G1 e de 3,69 mmMol/l no grupo G2 (p<0,05) No quinto dia de pós-operatório, os animais foram submetidos à eutanásia e tiveram suas anastomoses testadas por teste de resistência à pressão de ruptura à distensão por líquido. RESULTADOS: No grupo G1, o valor médio da pressão de ruptura do cólon à distensão por líquido foi de 160,7mmHg enquanto que no grupo G2 foi de 152,1mmHg (p>0,05). CONCLUSÃO: A presença de choque hemorrágico, nas condições estabelecidas neste estudo, não exerce influência em anastomoses de cólon em ratos, avaliadas com teste de ruptura à distensão por líquido.

Anemia severa causada por Necator americanus: reporte de un caso / Severe anemia caused by Necator americanus: case report

En climas templados, yungas (zona intermedia entre valle y trópico) y trópico, prevalecen dos parásitos hematófagos: Necator americanusy Ancylostoma duodenale, responsable de una anemia crónica, que lleva a los niños a tener niveles tan bajos de Hb, que a veces sonconsiderados incompatibles con la vida; rara vez originan sangrado agudo severo.Describimos el caso de un niño, de seis meses de edad, procedente de Coroico (Nor Yungas) con disentería inicial, misma que luego secomplica con melenas y rectorragia de sangre rutilante que origina una hipovolemia severa, rayana en el choque. Sometido a exploraciónquirúrgica por persistencia del sangrado, previo gammagrafía para descartar un divertículo de Meckel, no se halla el sitio de sangradopor lo que se realiza laparotomía exploratoria y posteriormente una endoscopía, identifi cándose en duodeno foco de sangrado originadopor parásitos, que por su morfología se asume que se trate de Necator americanus. Con este diagnóstico, recibe transfusiones para suestabilizar su hipovolemia y Mebendazol, con buena evolución, remisión del sangrado de tubo digestivo, y buena tolerancia a la alimentación.El “sangrado agudo” por uncinarias, es excepcional, hecho que justifi ca la presentación del caso y permite realizar un recordatorio breve delos mecanismos responsables de ello...

In temperate climate, yungas (intermediate zone between valley and tropical lowland), two blood sucking parasites are prevalent: Necator americanus and Ancylostoma duodenale, responsible for chronic anaemia in children that causes extremely low Hb levels sometimesconsidered as incompatible with life; only in rare cases acute bleeding occurs.We describe the case of a six months old child stemming from Coroico (Nor Yungas) initially with dysentery that becomes complicated by melaena and rectal bleeding originating severe hypovolaemia bordering on shock. After gammagraphy in order to exclude Meckel’s diverticle, the child was submitted to surgical exploration, where no source of bleeding could be found, therefore an explorative laparotomy was performed and later on an endoscopy, where the source of bleeding was identifi ed in the duodenum as caused by the parasite Necator Americanus. With this diagnose, blood transfusions were administered to the child in order to stabilize the hypovolaemia and Mebendazol was given. The evolution was good, the bleeding stopped and feeding was well tolerated.Acute bleeding caused by hook worms is exceptional; therefore we present this case as a short reminder of the responsible mechanisms.

Spectrum of renal disease in malaria.

Between January 2000 and December 2001, renal involvement in 81 cases of malaria was studied. Their age ranged between 05 and 66 (mean 35.5) years. Distribution of malarial parasite was P falciparum (75), mixed infection (4) and P vivax (2). The evidence of clinical renal disease in the form of acute renal failure, electrolyte abnormality, abnormal urinary sediment and increased urinary protein excretion (>500 mg/24 hours) was found in 100%, 91.3%, 46.9% and 18.5% respectively. Probable aetiopathogenesis of acute renal failure (ARF) was multifactorial. Volume depletion (72.8%) was the dominant cause of ARF in these patients. In addition, hyperbilirubinaemia, intravascular haemolysis and sepsis were responsible for ARF in 64.2%, 70.3% and 25.9% cases respectively. All the patients were managed with anti-malarial drugs and dialysis support was needed in 35 patients (43.2%). Prognosis of malarial acute renal failure is favourable with mortality rate of 18.5%. Multi-organ failure was the commonest cause (33.3%) of death.