Changes in circulating blood volume after cardiac surgery measured by a novel method using hydroxyethyl starch

Area of Science:

• Cardiovascular Surgery
• Critical Care Medicine
• Hemodynamics

Background:

• Postoperative blood volume (BV) changes are common in cardiac surgery patients.
• Understanding these changes is vital for managing perioperative complications.

Purpose of the Study:

• To quantify the incidence and extent of blood volume (BV) changes after elective cardiac surgery.
• To evaluate the utility of a new hydroxyethyl-starch dilution method for BV assessment.

Main Methods:

• Prospective clinical and laboratory investigation involving 35 patients undergoing cardiac surgery with cardiopulmonary bypass (CPB).
• Perioperative measurements included circulating BV, systemic hemodynamics, and lactate levels.
• Blood volume was determined using a novel hydroxyethyl-starch dilution technique.

Main Results:

• A significant percentage of patients exhibited postoperative BV deficits within 72 hours after CPB, despite positive fluid balance.
• BV deficits correlated with reduced mean arterial pressure, increased heart rate, and elevated lactate levels in the early postoperative period.
• Blood volume normalized by 24 hours post-CPB, with some patients showing a BV surplus at 48 and 72 hours.

Conclusions:

• Early postoperative hypovolemia is prevalent after cardiac surgery and linked to cardiovascular dysfunction and hyperlactemia.
• Rapid BV assessment is recommended to guide fluid therapy and optimize treatment, potentially reducing perioperative morbidity and mortality.