[Blood Loss in Open Spine Surgeries - Preoperative Estimate vs Reality]

Area of Science:

• Surgical Oncology
• Anesthesiology
• Orthopedics

Background:

• Intraoperative blood loss is a significant risk in spinal surgery, increasing complications and costs.
• Current methods for estimating blood loss are often inaccurate, particularly for substantial losses.

Purpose of the Study:

• To evaluate current blood loss estimation techniques in spinal surgery.
• To highlight the discrepancy between estimated and actual blood loss, focusing on hidden blood loss (HBL).

Main Methods:

• Analysis of Total Blood Loss (TBL) as Visible Blood Loss (VBL) + Hidden Blood Loss (HBL).
• Discussion of mathematical formulas (Gross equation, Nadler's formula) for TBL calculation.
• Review of research on blood loss in surgical sponges and suction canisters.

Main Results:

• Visual estimation significantly underestimates blood loss, especially >1000 ml.
• Surgical sponges capture ~21% of intraoperative blood loss in major spinal procedures.
• Hidden blood loss (HBL) constitutes at least 30% of total perioperative loss.
• A "28% coefficient" for suction canister volume aids realistic textile blood loss estimation.
• Visible blood in suction canisters may only be ~50% of TBL in extensive posterior thoracolumbar fusions.
• Younger patients exhibit higher HBL due to physiological factors.

Conclusions:

• Standard estimation methods are unreliable for spinal surgery.
• Accurate assessment of both visible and hidden blood loss is crucial for patient safety.
• Further research into HBL mechanisms and improved estimation strategies is warranted.