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Intranasal Calcium Channel Blocker as Potential Treatment for Acute SVT Termination
For reentrant types of supraventricular tachycardia (SVT), effective therapies for the acute termination include vagal maneuvers, intravenous (IV) adenosine, IV beta blockers, and IV calcium channel blockers. Vagal maneuvers, however, are the only option that can be performed outside an acute care setting. In a phase 2 trial of etripamil, an intranasally administered calcium channel blocker, SVT was terminated in up to 95 percent of patients. (J Am Coll Cardiol 2018;72:489.) If ongoing phase 3 trials confirm efficacy and safety, intranasal calcium channel blockers may become another option for acute SVT termination in out-of-hospital settings.
Bicarbonate Therapy for Critically Ill Patients with Metabolic Acidosis
Indications for bicarbonate therapy in metabolic acidosis are controversial, but most experts treat patients who have acute metabolic acidosis and severe acidemia (i.e., arterial pH <7.1) with bicarbonate therapy. There is less consensus about treatment of patients with less severe acidemia (e.g., pH 7.1 to 7.2). A randomized trial assigned 389 critically ill patients with metabolic acidosis (mean serum bicarbonate, 13 mmol/L, and most with elevated lactate levels) and acidemia (arterial pH ≤7.2, mean 7.15) to either intravenous infusions of sodium bicarbonate to maintain a pH >7.3 or to no sodium bicarbonate. (Lancet 2018;392:31.) Bicarbonate therapy had no overall effect on mortality at 28 days or organ failure at seven days, although there was a trend toward improved outcomes in the bicarbonate group. Among the subgroup of patients with severe acute kidney injury (defined as a twofold or greater increase in serum creatinine or oliguria), bicarbonate therapy reduced 28-day mortality (46 versus 63 percent) and the need for dialysis (51 versus 73 percent). For patients with acute metabolic acidosis and an arterial pH 7.1 to 7.2, UpToDate suggests bicarbonate therapy when severe acute kidney injury is also present.
Incidence of and Risk Factors for Overly Rapid Correction of Hyponatremia
In patients with severe hyponatremia (serum sodium <120 mEq/L), overly rapid correction of the serum sodium (defined as an increase of more than 8 mEq/Lin a 24-hour period) may produce serious neurologic manifestations referred to as the osmotic demyelination syndrome. In a large retrospective cohort study of hospitalized patients admitted with serum sodium <120 mEq/L, overly rapid correction at 24 hours was identified in 41 percent. (Clin J Am Soc Nephrol 2018;13:984.) A lower initial serum sodium was an independent risk factor for overly rapid correction, as were schizophrenia and a lower baseline urine sodium concentration (factors which often correspond to an etiology of hyponatremia that is quickly reversible). Of the patients with overly rapid correction, one percent developed osmotic demyelination syndrome, of whom most had hypovolemia, hypokalemia, and a history of alcohol use and/or malnutrition. Overly rapid correction is common among patients with severe hyponatremia and may produce devastating neurologic consequences.
Alteplase Versus Aspirin for Minor, Nondisabling Acute Ischemic Stroke
Qualifying patients who have an acute ischemic stroke causing a persistent neurologic deficit that is potentially disabling should be treated urgently with intravenous alteplase and/or mechanical thrombectomy as appropriate. Whether intravenous alteplase is beneficial for patients with mild, nondisabling ischemic stroke is unknown. In the PRISMS trial, which enrolled patients with acute ischemic stroke within three hours of symptom onset and deficits judged not clearly disabling, there was no difference in the rate of a favorable functional outcome for patients assigned to treatment with intravenous alteplase or to aspirin (78 versus 82 percent). (JAMA 2018;320:156.) However, these findings are not definitive because the trial was stopped very early due to slow recruitment, having enrolled only one-third of more than 900 planned subjects.
Fluid Management and Cerebral Injury in Diabetic Ketoacidosis
Cerebral injury is an uncommon, but potentially devastating, consequence of diabetic ketoacidosis (DKA). Whether the rate and type of fluid used for rehydration affects the risk of cerebral injury has been unclear. In a multicenter randomized trial that evaluated four rehydration protocols (more rapid versus slower fluid administration with half-normal versus normal saline) after standard initial normal saline bolus in children with DKA, neurologic outcomes were similar regardless of rate of administration or sodium chloride content. (N Engl J Med 2018;378:2275.) Thus, children with DKA can be safely rehydrated with various protocols of fluid replacement, within the range explored in this trial.
Oral Administration of Honey or Sucralfate after Button Battery Ingestion in Children
Guidelines for the management of button battery ingestion previously recommended no oral intake before timely radiographic localization and emergency endoscopic removal of esophageal button batteries. A recent study using in vitro and in vivo animal models of esophageal battery impaction suggests that early and repeated oral administration of either honey or sucralfate until the battery is removed may reduce the severity of esophageal burns.(Laryngoscope 2018 Jun 11. doi: 10.1002/lary.27312.) For asymptomatic children with acute button battery ingestions (e.g., witnessed or likely to have occurred within one to two hours) who are older than 1 year of age and who have no allergies to honey or its components, we suggest one oral dose of pure honey (e.g., 5 to 10 mL) as soon as possible after ingestion. Once in the emergency department, the child may receive another dose of honey or a single dose of sucralfate 500 mg prior to confirmation of esophageal impaction and emergency battery removal. Although this approach runs counter to the usual approach of no oral intake until operative removal, the benefit of neutralization and reduction in burn injury to the esophagus appears to outweigh the potential increased risk of aspiration.
Low Incidence of Serious Traumatic Brain Injury in Children with Isolated Skull Fractures
In a meta-analysis of 21 studies that reported on outcomes of more than 6500 children with isolated linear nondisplaced skull fractures identified by neuroimaging, only one child underwent emergency neurosurgery and no patients died. (Ann Emerg Med 2018;71:714.) Thus, the risk of clinically important traumatic brain injury in neurologically normal children with isolated linear skull fractures and no concern for child abuse is low and hospitalization of these patients is usually unnecessary.
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