UMEM Educational Pearls

Title: Risk of Overcorrection in Rapid Intermittent Bolus vs Slow Continuous Infusion Therapies of Hypertonic Saline for Patients With Symptomatic Hyponatremia: The SALSA Randomized Clinical Trial

Keywords: Hyponatremia (PubMed Search)

Posted: 11/12/2020 by Caleb Chan, MD
Click here to contact Caleb Chan, MD

Significance:

There have been few high-quality studies regarding slow continuous infusion (SCI) of hypertonic vs. rapid intermittent bolus (RIB) therapy for patients with symptomatic hyponatremia

Study Design:

Multicenter, open-label RCT with 178 patients (both ED and inpatient) with corrected Na of 125 mml/L or lower with moderate/severe symptoms

-Moderate symptoms: nausea, headache, drowsiness, general weakness, and malaise

-Severe symptoms: vomiting, stupor, seizure, and coma (Glasgow Coma Scale [GCS] score ≤8)

Relevant excluded patient populations: liver disease/cirrhotics, uncontrolled diabetics, primary polydypsia, anuric, hypotensive

Intervention:

Slow continuous infusion (SCI) of hypertonic vs. Rapid intermittent bolus (RIB) therapy

(see treatment algorithms for specifics)

Results:

Primary outcome: No difference in rates of overcorrection

15 of 87 (17.2%) patients in the RIB group vs. 22 of 91 (24.2%) patients in the SCI group

-(absolute risk difference, −6.9% [95% CI, −18.8% to 4.9%]; P = .26)

Other outcomes:

RIB group showed a lower incidence of relowering treatment than the SCI group

-(absolute risk difference, −15.8% [95% CI, −30.3% to −1.3%]; P = .04; NNT, 6.3)

RIB group had higher proportion of patients achieving target correction rate within 1 hour than the SCI group

-(absolute risk difference, 14.6% [95% CI, 2%-27.2%]; P = .02; NNT, 6.8)

No significant differences between the groups were observed in:

- symptoms at 24 and 48 hours after treatment initiation

- first time to an increase in sNa 5 mmol/L or greater after treatment initiation

- incidence of target correction rate

- time from treatment initiation to achievement of sNa greater than 130 mmol/L

- length of hospital stay

There were no cases of osmotic demyelination syndrome in either group

Take-home point:

Rapid intermittent boluses of hypertonic saline may be just as effective as slow continuous infusions for certain patient populations with moderate/severe symptomatic hyponatremia (and may actually have decreased rates of need for re-lowering treatment)

Limitations:

-smaller study

-high number of dropout due to protocol violation

-remember that ODS is multifactorial (liver disease, chronic alcoholism, malnutrition)

References

Baek SH, Jo YH, Ahn S, et al. Risk of overcorrection in rapid intermittent bolus vs slow continuous infusion therapies of hypertonic saline for patients with symptomatic hyponatremia: the salsa randomized clinical trial. JAMA Intern Med. Published online October 26, 2020.