Hypotonic enteral electrolyte solutions administered by nasoesophageal tube in continuous flow in dogs dehydrated by water restriction: Part 1 / Soluções eletrolíticas enterais hipotônicas administradas por sonda nasoesofágica em fluxo contínuo em cães desidratados por restrição hídrica: Parte 1

The present study assessed and compared the effects of hypotonic enteral electrolyte solutions administered by nasoesophageal tube in continuous flow in dogs submitted to water restriction on packed cell volume; total serum protein and serum osmolarity concentrations; blood volume; plasma glucose and lactate levels; blood gas analysis, anion gap, and strong ion difference. Six adult dogs were used (four males and two females). All animals were submitted to both proposed treatments in a crossover design 6×2. The treatments were as follows: ESmalt consisting of 5g sodium chloride, 1g potassium chloride, 1g calcium acetate, 0.2g magnesium pidolate, and 9.6g maltodextrin that were diluted in 1.000mL water (measured osmotic concentration of 215mOsm L−1) and ESdext consisting of 5g sodium chloride, 1g potassium chloride, 1g calcium acetate, 0.2g magnesium pidolate, and 9.6g dextrose that were diluted in 1.000mL water (measured osmotic concentration of 243mOsm L−1). All solutions were administered at 15ml kg−1 h−1 for 4 hours. Both solutions increased the plasma volume in dehydrated dogs without causing adverse effects. However, ESmalt was more effective in promoting the increase in blood volume.(AU)

O presente estudo avaliou e comparou os efeitos de soluções eletrolíticas enterais hipotônicas, administradas por sonda nasoesofágica em fluxo contínuo em cães submetidos a restrição hídrica, sobre o hematócrito, proteínas totais séricas, osmolaridade sérica, volemia, glicose e lactato plasmáticos, hemogasometria, ânion gap e DIF. Foram utilizados seis cães adultos (quatro machos e duas fêmeas). Todos os animais foram submetidos aos dois tratamentos propostos, em um delineamento crossover 6×2. Os tratamentos foram os seguintes: SEmalt - 5g de cloreto de sódio, 1g de cloreto de potássio, 1g de acetato de cálcio, 0,2g de pidolato de magnésio e 9,6g de maltodextrina, diluídos em 1.000mL de água (osmolaridade mensurada: 215mOsm L -1 ); SEdext - 5g de cloreto de sódio, 1g de cloreto de potássio, 1g de acetato de cálcio, 0,2g de pidolato de magnésio e 9,6g de dextrose, diluídos em 1.000mL de água (osmolaridade mensurada: 243mOsm L -1 ). Todas as soluções foram administradas no volume de 15mL kg -1 hora -1 , durante quatro horas, em fluxo contínuo. Ambas as soluções aumentaram o volume plasmático em cães desidratados, sem gerar o aparecimento de efeitos adversos. Porém, a SEmalt foi mais eficaz em promover a expansão da volemia.

Pulmonary edema in the transurethral resection syndrome induced with mannitol 5%.

Two patients developed the transurethral resection (TUR) syndrome after having absorbed mannitol 5% during TUR of the prostate. Both developed pulmonary edema and became severely hypoatremic (lowest serum sodium 99 and 97 mmol/l, respectively). Hypertonic saline was infused to raise the serum sodium level and plasma volume expansion used to combat hypotension. One patient also required positive-pressure ventilation and intravenous administration of norepinephrine. Both patients recovered completely.

Hypotonic water as adjuvant therapy for incompletely resected canine mast cell tumors: a randomized, double-blind, placebo-controlled study.

OBJECTIVE: To evaluate efficacy of hypotonic water as adjuvant therapy after marginal resection of canine mast cell tumors (MCT). STUDY DESIGN: Double-blinded, placebo-controlled, prospective, randomized study. ANIMALS: Dogs (n=30) with spontaneous, cutaneous, solitary MCT. METHODS: The wound bed of MCT, resected with margins <0.5 cm, was injected with either hypotonic or isotonic water according to a standardized protocol. Follow-up was obtained by clinical examination at 1, 2, 3, 6, and 12 months and annual telephone contact with the owner. RESULTS: Eighteen dogs were treated with isotonic lactated Ringer's solution and 12 dogs with hypotonic distilled water. All MCT were stage 0 tumors and most grade II. Six tumors (4 isotonic, 2 hypotonic) recurred locally, 3 of these dogs died from disease-related reasons within 4 months. The surviving 3 dogs were alive with a median survival time (ST) of 1092 days. The calculated 2-year recurrence-free rate was 92.7%; the 2-year disease-free rate 79.1%; and the 2-year survival rate 89.5%. No significant differences in local recurrence and ST were observed between treatment groups. Histologic grading was the only significant prognosticator for ST and recurrence-free periods. CONCLUSION: No significant differences in local recurrence and ST were observed between adjunctive hypotonic water and placebo treatment after marginal resection of solitary MCT. CLINICAL RELEVANCE: Hypotonic water does not decrease the rate of local recurrence in dogs with solitary MCT after marginal surgical excision.

Reinduction of hyponatremia improves survival in rats with myelinolysis-related neurologic symptoms.

Brain myelinolysis occurs after excessive correction (delta SNa > 20 mEq/1/24 hours) of chronic hyponatremia. However, we showed recently that the mechanisms leading to brain myelinolysis remain reversible. Indeed, reinduction of the hyponatremia by water administration despite 12 hours of sustained excessive correction could prevent the development of demyelination in rats still asymptomatic at that time. Whether this therapeutic maneuver could be also beneficial to rats with preexisting myelinolysis-related neurologic symptoms is unknown. Therefore we evaluated here the effect of reinduction of the hyponatremia on the survival and on brain damage in rats presenting obvious neurologic symptoms after excessive correction of hyponatremia. After 3 days of severe hyponatremia induced by 2.5 D-glucose in water and continuous infusion of AVP, rats were submitted to a large correction (delta SNa approximately 30 mEq/l) by 2 i.p. injections of hypertonic saline given over 24 hours. In group I (n = 15) the rats developing neurologic symptoms during the first 24 hours of correction received one i.p. injection of distilled water which rapidly decreased the natremia to a final correction gradient <20 mEq/l/24 hour. In group II (n = 13, controls) the symptomatic rats were left permanently overcorrected. In group I, after water administration, the neurological manifestations were generally attenuated or disappeared. Seven of the 15 rats (47%) in this group survived up to day 10 with a mean survival time of 7.5 +/- 2 days, an outcome clearly improved as compared to group II (controls): only 1 of the 13 rats (7%, p < 0.03) was still alive on day 10 and the mean survival time was 3.3 +/- 2 days (p < 0.001) in this group II. The duration of the symptoms also influences the prognosis. In group I, in 9 rats the water administration was performed 4 hours after symptoms onset. These rats had a better outcome than the 6 rats with more sustained (8-10 hours) neurologic symptoms before water loading. Brain analysis in the 7 surviving rats of group I demonstrated demyelinating lesions in only 2 of them, suggesting the reversibility of the process even when neurologic manifestation developed. In conclusion, after exposure to an excessive correction of chronic hyponatremia, even when rats have developed myelinolysis-related neurologic symptoms, hypotonic fluids administration could improve survival and could prevent the subsequent development of brain myelinolysis.