RCA territory event after CPB separation — air or fixed obstruction?
Isolated CABG. Lead II ST elevation, CVP spikes, and BP drops immediately after CPB separation. RCA air embolism or graft/anastomosis problem? Read TEE, monitors, and the surgeon's field view together to decide.
Intraoperative setup
Isolated CABG (LAD, RCA, LCx). Immediately after separating from CPB, prominent lead II ST elevation appears. CVP jumps from 8 to 18 mmHg. Systolic BP drops from 95 to 70 mmHg. HR 90 bpm. PA catheter: PA pulse pressure narrows (38/18 → 36/26 mmHg) and PAPi has fallen. The perfusionist says 'happened right after declamping.' The surgeon says 'the RV looks tense — not moving great.' LV is 'still appearing to contract globally.'
What this case is really asking
- Prominent lead II ST elevation + acute CVP spike — this is an RCA territory event. Air embolism or graft/anastomosis problem?
- Is there inferior RWMA and bright flickering echogenicity on TEE — looking for direct evidence of air embolism
- Is there residual air in the aortic root or left heart — assessing risk of further coronary air delivery
- Is LV global contractility relatively preserved — distinguishing from global LV pump failure
- Will the picture improve over 5–10 minutes — the single most important differentiator between air embolism and fixed obstruction
TEE clues to notice
- LV inferior RWMA: confirmed on deep transgastric view or transgastric short-axis — inferior and posterior wall hypokinesis?
- Bright flickering echogenicity: high-intensity echoes in the inferior myocardium or near the RCA — direct sign of air embolism
- Residual air in aortic root/Valsalva sinuses/left heart: floating bright echoes — indicates ongoing risk of coronary air delivery
- LV global contractility: relatively preserved — essential for distinguishing an RCA territory event from global pump failure
- RV enlargement and reduced contractility: note on TEE but do not over-interpret — TEE has limited windows for the full RV including the apex; the surgeon standing at the field is the fastest and most reliable RV assessment
Likely pattern
Two patterns differentiated by time course. Don't commit to one within the first minute. RCA Air Embolism: Right after CPB separation — lead II ST elevation + acute CVP spike + BP drop. Surgeon reports RV distension and reduced motion at the field. TEE: inferior RWMA + bright flickering echogenicity ± residual air in the aortic root. The practical goal is to maintain coronary perfusion pressure and promote washout of air from the RCA territory — increase CPB flow when appropriate, raise SVR if needed, and target MAP/coronary perfusion pressure around 70–80 mmHg. The hemodynamic goal matters more than the choice of vasopressor. If head-down positioning is used, the intent is to reduce air migration toward the cerebral circulation — it does not directly treat coronary air. Over the next 5–10 minutes, actively track ST elevation, CVP, PA pulse pressure, BP, RV motion, and inferior RWMA. If these improve, air embolism is the likely explanation. If not, consider RCA graft failure, anastomotic problem, coronary spasm, or RCA injury — proceed to surgical inspection or return to CPB. Fixed RCA Obstruction/Graft Problem: The same ST elevation + RV failure + inferior RWMA persists or worsens beyond 5–10 minutes. Bright flickering echoes are absent or not the dominant finding. In isolated CABG: RCA graft occlusion, anastomotic problem, or coronary spasm. In AVR: RCA ostium obstruction (suture line encroaching on the RCA ostium) or intraoperative RCA injury should be suspected first — tell the surgeon 'please check the RCA ostium.' If no improvement: consider surgical field inspection or return to CPB. Distinguishing from global LV pump failure: When LV global contractility is severely reduced, global pump failure is the primary problem. In an RCA territory event, LV global function is relatively preserved — the RV is the dominant problem. LV contracting but BP still low → think RV failure, not LV pump failure.
Common pitfall
'LV is moving globally so it must be fine' — in RCA territory events, LV global function is typically preserved and the problem is in the RV. Dismissing CVP elevation as 'expected after CPB' — an acute spike is a signal, not background noise. Spending time trying to measure RV FAC on TEE when the surgeon at the field can see the RV directly in real time — that is the fastest and most reliable RV assessment available. Committing to air embolism or fixed obstruction within the first 60 seconds — the initial findings often overlap and time course is the differentiator.
Immediate intraoperative takeaway
- Lead II ST elevation + acute CVP spike = RCA territory event first — ask the surgeon immediately about the RV appearance at the field
- Air embolism vs fixed obstruction: time course is the most important differentiator — don't commit in the first minute
- RV assessment is fastest and most accurate from the surgical field — measuring RV FAC on TEE is too slow for this scenario
- Inferior RWMA + bright flickering echoes + aortic root air = strong support for air embolism as a pattern
- If no improvement after 5–10 minutes: in CABG think graft failure or spasm; in AVR think RCA ostium obstruction — consider surgical inspection or re-CPB