Obesity decreases perioperative tissue oxygenation

Area of Science:

• Surgical Science
• Physiology
• Obesity Research

Background:

• Obesity is a significant risk factor for surgical site infections.
• Reduced tissue perfusion and oxygenation in obese patients may contribute to higher infection rates.
• Fat tissue expansion without proportional blood flow increase can lead to relative hypoperfusion and hypoxia.

Purpose of the Study:

• To test the hypothesis that perioperative tissue oxygen tension is reduced in obese surgical patients.
• To compare the effect of supplemental oxygen on tissue oxygenation in obese versus nonobese patients.

Main Methods:

• Forty-six patients undergoing major abdominal surgery were divided into obese (BMI ≥ 30 kg/m2) and nonobese (BMI < 30 kg/m2) groups.
• Intraoperative oxygen administration was adjusted to target arterial oxygen tensions of approximately 150 mmHg and 300 mmHg.
• Subcutaneous tissue oxygen tension was measured using a polarographic electrode in the upper arm and near the wound, throughout the perioperative period.

Main Results:

• Obese patients exhibited significantly lower intraoperative subcutaneous tissue oxygen tension at baseline and with supplemental oxygen.
• Immediate postoperative tissue oxygen tension was significantly reduced in both subcutaneous tissue and near the incision in obese patients.
• Tissue oxygen tension became comparable between groups on the first postoperative morning.

Conclusions:

• Perioperative wound and tissue hypoxia are prevalent in obese patients, particularly during surgery.
• Even with supplemental oxygen, obese patients maintained reduced tissue oxygen tension, correlating with increased infection risk.
• These findings highlight the critical impact of obesity on perioperative tissue oxygenation and infection susceptibility.