What is the preferred central venous pressure zero reference for hepatic resection?

Area of Science:

• Hepatobiliary surgery
• Anesthesiology
• Medical imaging

Background:

• Maintaining central venous pressure (CVP) below 5 mm Hg during hepatic resection aims to reduce bleeding but elevates the risk of venous air embolism (VAE).
• The liver's anteroposterior (AP) diameter often exceeds 7 cm, the hydrostatic pressure equivalent to 5 mm Hg CVP, creating a potential monitoring challenge.
• Variability in liver dimensions necessitates a re-evaluation of standard CVP transducer placement during liver surgery.

Purpose of the Study:

• To characterize the anteroposterior (AP) diameter of the liver in adults.
• To assess the impact of liver AP diameter on central venous pressure (CVP) transducer placement.
• To optimize CVP monitoring to balance the risks of hemorrhage and venous air embolism (VAE) during hepatic resection.

Main Methods:

• Retrospective analysis of archived chest tomograms with IV contrast from 100 adult patients.
• Measurement of the anteroposterior (AP) liver diameter and its relationship to other anatomical landmarks.

Main Results:

• Demonstrated a wide interindividual variation in AP liver dimensions, with a mean of 17.9 ± 2.8 cm (range: 12.0–28.5 cm).
• Identified standardized anatomical landmarks relative to the portal triad for reference.

Conclusions:

• Significant variability in AP liver diameter and surgical site anatomy warrants a revised approach to CVP transducer zeroing during hepatic surgery.
• Prioritizing direct measurement of hepatic venous pressure over CVP can mitigate risks of VAE and hemorrhage.
• Proposed two novel methods for zeroing the reference transducer to improve patient safety in liver surgery.