Why do some surgeons prefer one-lung anesthesia (OLA) for off-pump coronary artery bypass (OPCAB) via median sternotomy approach?

One-Lung Anesthesia for OPCAB via Median Sternotomy

Some surgeons prefer one-lung anesthesia (OLA) during median sternotomy OPCAB primarily to improve surgical exposure and facilitate hemostasis, though this practice is not standard and remains surgeon-specific rather than guideline-recommended.

Primary Rationale for OLA in Sternotomy OPCAB

The use of single-lung ventilation in median sternotomy OPCAB is not a standard requirement but rather a technique preference among certain surgeons. The evidence base for this practice comes primarily from minimally invasive cardiac surgery literature rather than conventional sternotomy OPCAB guidelines.

Surgical Exposure Benefits

• Single-lung ventilation can facilitate identification of anatomic landmarks before initiating cardiopulmonary bypass, particularly useful in reoperative cases where lung adhesions need division 1
• Deflating the right lung improves visualization of cardiac structures and provides "straight-on" access to surgical targets, though this benefit is more pronounced in thoracotomy approaches than sternotomy 1
• Hemostasis is significantly facilitated at the end of the procedure with the lung deflated, allowing better visualization of bleeding points 1

Technical Considerations

The decision to use OLA in sternotomy OPCAB appears to be experience-dependent and surgeon-specific rather than evidence-based:

• Some experienced surgeons prefer not to use single-lung ventilation even in minimally invasive approaches, accepting increased CPB times as a trade-off 1
• Anesthetic management for OPCAB requires standardization according to guidelines, but specific ventilation strategies are not mandated 1
• The technique comes at the expense of increased operative complexity without clear outcome benefits in the sternotomy approach 1

Important Caveats and Contraindications

Physiologic Tolerance Issues

• Not all patients tolerate single-lung ventilation, with persistent oxygen desaturation occurring in some cases requiring conversion to double-lung ventilation 2
• Patients with higher BMI, higher STS scores, and more extensive coronary disease are more likely to be intolerant of single-lung ventilation 2
• Intolerance of single-lung ventilation does not preclude successful OPCAB, as double-lung ventilation remains feasible with similar outcomes 2

Lack of Guideline Support

No major cardiac surgery guidelines specifically recommend OLA for conventional median sternotomy OPCAB 1, 3. The guidelines emphasize:

• Standardization of anesthetic techniques for OPCAB is needed but specific ventilation strategies are not prescribed 1
• Off-pump CABG should only be performed by surgeons with extensive experience given technical complexity, but ventilation strategy is not addressed 3
• The primary focus remains on avoiding aortic manipulation rather than ventilation strategy for reducing complications 1, 3

Clinical Bottom Line

The use of OLA in median sternotomy OPCAB represents individual surgeon preference rather than evidence-based practice. The technique may offer marginal improvements in surgical field visualization and hemostasis but:

• Adds anesthetic complexity without demonstrated outcome benefits in the sternotomy approach 1, 2
• May not be tolerated by all patients, particularly those with higher risk profiles 2
• Is not mentioned or recommended in major CABG guidelines as a standard technique 1, 3

For conventional median sternotomy OPCAB, standard two-lung ventilation remains appropriate for most patients, with OLA reserved for specific surgeon preference or anatomic considerations rather than routine practice 1, 2.