Hyponatremia after Autologous Breast Reconstruction: A Cohort Study Comparing Two Fluid Management Protocols

Area of Science:

• Surgical Oncology
• Plastic Surgery
• Nephrology

Background:

• Perioperative fluid management is crucial for enhanced recovery after microsurgical breast reconstruction.
• Historically liberal fluid management protocols have been associated with biochemical complications, particularly hyponatremia.
• This study addresses the need for optimized fluid management to mitigate postoperative hyponatremia.

Purpose of the Study:

• To introduce and evaluate a novel, "modestly restrictive" postoperative fluid management protocol.
• To reduce the incidence and severity of hyponatremia in patients undergoing microsurgical breast reconstruction.
• To analyze the biochemical effects of different fluid management strategies.

Main Methods:

• A single-institution cohort study compared a prospective group using a new "modestly restrictive" protocol with a historical "liberal" fluid management control group.
• The study included 130 patients undergoing microsurgical breast reconstruction in 2021.
• Fluid balance, incidence of hyponatremia, and risk factors for hyponatremia were assessed.

Main Results:

• The liberal fluid management protocol was associated with a mean postoperative day 1 fluid balance of +2,838 mL, with 36% of patients developing hyponatremia.
• The new "modestly restrictive" protocol reduced mean fluid balance to +844 mL (p ≤ 0.0001) and decreased hyponatremia incidence to 14% (p = 0.0005).
• Oral water intake between 8 am and 8 pm on postoperative day 1 was identified as a significant risk factor for hyponatremia (OR: 7; p = 0.019).

Conclusions:

• The original liberal fluid protocol, encouraging excessive oral water intake (up to 5L/day), frequently led to moderate-to-severe hyponatremia.
• The new protocol, featuring early IV fluid cessation and an oral fluid limit of 2,100 mL/day, significantly reduced hyponatremia and fluid overload.
• Modest fluid restriction effectively protects patients from hyponatremia, demonstrating its clinical utility in microsurgical breast reconstruction.