From the Research
Fluid boluses are not recommended in tetralogy of Fallot (TOF) spells as they can worsen the condition. The most recent and highest quality study, 1, published in 2022, describes the evolving in-hospital management strategies for neonates with ToF, but does not specifically address the use of fluid boluses in TOF spells. However, based on the pathophysiology of TOF spells, which are characterized by increased right ventricular outflow tract obstruction and decreased systemic vascular resistance, leading to cyanosis, fluid boluses would likely exacerbate the condition by increasing venous return and worsening right-to-left shunting across the ventricular septal defect. Instead, immediate management should focus on:
- Placing the infant in a knee-chest position
- Administering oxygen
- Giving phenylephrine at 5-20 mcg/kg IV push or morphine sulfate at 0.1-0.2 mg/kg IV/IM/SC
- Beta-blockers like propranolol (0.1-0.2 mg/kg IV slowly) may be used if other measures fail, as mentioned in the example answer. The goal of treatment is to increase systemic vascular resistance and decrease pulmonary vascular resistance, thereby reducing right-to-left shunting. Administering fluids would have the opposite effect by potentially increasing right ventricular volume and pressure, worsening the obstruction and shunting. Other studies, such as 2, 3, 4, and 5, provide information on the treatment and management of TOF, but do not specifically address the use of fluid boluses in TOF spells. Therefore, the recommendation to avoid fluid boluses in TOF spells is based on the underlying pathophysiology of the condition and the potential for fluids to worsen the condition.