Israel Medical Association Journal

Background: Methylene blue (MB), an inhibitor of nitric oxide synthesis and its effects is a potentially effective treatment against distributive shock states such as septic shock and vasoplegic syndrome. MB has been shown to alleviate vasoplegia and promote an increase in blood pressure. It may reduce mortality. However, in the pediatric population, there are few case reports and only one controlled study on administration of MB use for vasoplegia, sepsis, or shock in general.

Objectives: To summarize the experience of administering MB for vasoplegic shock in a tertiary care pediatric intensive care unit.

Methods: A retrospective chart review of seven pediatric cases treated with MB for vasoplegic shock was conducted. MB was administered as a bolus followed by continuous infusion. The authors measured blood pressure, vasopressor, and inotropic support. Patient outcome was monitored.

Results: The authors observed a favorable hemodynamic response with an increase in blood pressure and a reduction in vasopressor and inotropic support needed following MB administration in six patients. No side effects were observed. Three patients eventually died one to two days later, secondary to their underlying disease.

Conclusions: This case series adds to the small body of evidence in the pediatric population supporting the use of MB for distributive shock states and emphasizes the need for larger, randomized trials evaluating its role in vasoplegic shock treatment.

Background: Exposure of newborn animals to high concentrations of oxygen leads to diffuse alveolar damage similar to that seen in bronchopulmonary dysplasia in human infants. Therefore, neonatal rats are a suitable practical model of hyperoxic lung damage in human infants.

Objective: To determine the involvement of tumor necrosis factor-alpha and interleukin-6 in lung injury in neonatal rats exposed to 100% O2 concentration.

Methods: A randomized controlled study was designed in which litters of term Sprague-Dawley rat pups were assigned to experimental or control groups. The pups in the experimental group were placed in 100% O2 from birth for 9 days, while the control pups were placed in room air. Twelve to 15 pups from each group were sacrificed on day 1, 3, 6, 9 and 13 after birth for bronchoalveolar lavage collection and lung histologic study. The bronchoalveolar lavage fluid was assayed for TNFα and IL-6.

Results: Newborn rats exposed to 100% O2 for the first 9 days of life showed severe pulmonary edema and hypercellularity on days 1 and 3, which then improved to nearly complete resolution on days 6 and 9. Pulmonary TNFα was produced early on O2 exposure (day 3) and pulmonary IL-6 later (days 6 and 9).

Conclusions: Hyperoxia induces sequential production of pulmonary TNFα and IL-6, which corresponds to the severity of the pathological findings and the known inflammatory and anti-inflammatory role of these cytokines.

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TNFα= tumor necrosis factor-alpha

IL-6= interleukin-6