Abstract
Background Perioperative fluid management is an important component of enhanced recovery pathways
for microsurgical breast reconstruction. Historically, fluid management has been liberal.
Little attention has been paid to the biochemical effects of different protocols.
This study aims to reduce the risk of postoperative hyponatremia by introducing a
new fluid management protocol.
Methods A single-institution cohort study comparing a prospective series of patients was
managed using a new “modestly restrictive” fluid postoperative fluid management protocol
to a control group managed with a “liberal” fluid management protocol.
Results One-hundred thirty patients undergoing microsurgical breast reconstruction, at a
single institution during 2021, are reported. Hyponatremia is demonstrated to be a
significant risk with the original liberal fluid management protocol. At the end of
the first postoperative day, mean fluid balance was +2,838 mL (± 1,630 mL). Twenty-four
patients of sixty-five (36%) patients had low blood sodium level, 14% classified as
moderate-to-severe hyponatremia. Introducing a new, “modestly-restrictive” protocol
reduced mean fluid balance on day 1 to +844 mL (±700) (p ≤ 0.0001). Incidence of hyponatremia reduced from 36 to 14% (p = 0.0005). No episodes of moderate or severe hyponatremia were detected. Fluid intake,
predominantly oral water, between 8am and 8pm on the first postoperative day is identified
as the main risk factor for developing hyponatremia (odds ratio [OR]: 7; p = 0.019). Modest fluid restriction, as guided by the new protocol, protects patients
from low sodium level (OR: 0.25; confidence interval: 95%; 0.11–1.61; p = 0.0014).
Conclusion The original “liberal” fluid management protocol encouraged unrestricted postoperative
oral intake of water. Patients were often advised to consume in excess of 5 L in the
first 24 hours. This unintentionally, but frequently, was associated with moderate-to-severe
hyponatremia. We present a new protocol characterized by early cessation of intravenous
fluid and an oral fluid limit of 2,100 mL/day associated with a significant reduction
in the incidence of hyponatremia and fluid overload.
Keywords
breast reconstruction - hyponatremia - perioperative management
