Pilot study with air-automated sigmoid capnometry in abdominal aortic aneurysm surgery

Area of Science:

• Cardiovascular Surgery
• Gastroenterology
• Critical Care Medicine

Background:

• Ischaemic colitis is a severe complication following aortic surgery, often diagnosed late due to subtle clinical signs.
• Intestinal perfusion monitoring is crucial for early detection and management of postoperative complications.
• Automated tonometry offers a potential solution for continuous monitoring of intestinal perfusion.

Purpose of the Study:

• To evaluate the efficacy of semi-continuous sigmoid-to-arterial PCO2 gap (P(r-a)CO2) monitoring for detecting colonic ischaemia during and after aortic surgery.
• To assess the correlation between P(r-a)CO2 levels and conventional monitoring parameters, as well as colonic mucosal status.

Main Methods:

• A prospective clinical study involving eight male patients undergoing abdominal aortic aneurysm surgery.
• Continuous intraoperative and postoperative P(r-a)CO2 monitoring over 48 hours.
• Comparison of P(r-a)CO2 values with haemodynamic variables, oxygen delivery/consumption/extraction, lactate, and sigmoidoscopy findings.

Main Results:

• P(r-a)CO2 values significantly increased during aortic clamping and remained elevated for up to 12 hours postoperatively.
• The highest P(r-a)CO2 levels correlated with altered haemodynamic status, reduced oxygen delivery, and increased oxygen extraction.
• Elevated P(r-a)CO2 was associated with severe ischaemic colitis and longer hospital stays.

Conclusions:

• Semi-continuous, automated capnometry (P(r-a)CO2 monitoring) is a feasible and non-invasive method for detecting peroperative intestinal ischaemia in aortic surgery.
• This technique aids in early identification of compromised intestinal perfusion, potentially leading to timely interventions.
• P(r-a)CO2 monitoring offers valuable insights into intestinal perfusion dynamics following major vascular procedures.