Changes in plasma and buffy layer vitamin C following surgery

Area of Science:

• Biochemistry
• Clinical Nutrition
• Surgical Research

Background:

• Postoperative vitamin C levels are crucial for patient recovery.
• Previous studies indicated significant drops in plasma and buffy layer vitamin C after surgery.
• The precise mechanisms and implications of these changes required further investigation.

Purpose of the Study:

• To investigate postoperative changes in plasma and buffy layer vitamin C.
• To determine the effect of varying vitamin C supplementation doses on these levels.
• To identify the causes of observed changes in vitamin C concentrations and assess the validity of buffy layer measurements.

Main Methods:

• Plasma and buffy layer (BL) vitamin C levels were measured in 107 patients.
• Patients received daily supplementation of 0 mg, 100 mg, or 500 mg of vitamin C.
• Buffy layer vitamin C changes were correlated with leukocyte and platelet counts.

Main Results:

• Plasma vitamin C significantly decreased by 33% on the first postoperative day in non-supplemented patients.
• This decrease was influenced by initial concentration and operation length, likely due to increased urinary excretion.
• Postoperative buffy layer vitamin C changes were identified as a methodological artifact related to platelet-to-leukocyte ratio variations, not a true cellular demand.

Conclusions:

• Increased urinary excretion during surgery is the primary cause of postoperative plasma vitamin C decline.
• Routine buffy layer vitamin C estimation methods are unreliable due to cell count artifacts.
• No true cellular demand for vitamin C was evident from buffy layer measurements in the postoperative period.