During CPR, an arterial line is in situ. The diastolic arterial pressure during chest compressions is consistently below 25 mmHg. What does this indicate about CPR quality, and what immediate action is most appropriate?

• A CPR is adequate; continue current rate and depth
• B Diastolic pressure is irrelevant during CPR; focus on ETCO2
• C Increase ventilation rate to improve oxygenation
• D Diastolic pressure <25 mmHg indicates inadequate coronary perfusion pressure (CPP); improve compression depth/rate and consider vasopressors (adrenaline) ✓

Explanation

Coronary perfusion pressure (CPP) = aortic diastolic pressure minus right atrial diastolic pressure (≈ aortic diastolic pressure during CPR). A CPP >15–20 mmHg is associated with return of spontaneous circulation (ROSC). Diastolic arterial pressure <25 mmHg during CPR signals inadequate compressions and/or inadequate vasomotor tone. Immediate actions include optimising compression depth (5–6 cm) and rate (100–120/min), ensuring full chest recoil, and administering adrenaline 1 mg IV (repeated every 3–5 minutes). ETCO2 ≥10 mmHg or a sudden rise to ≥40 mmHg signals ROSC.

Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.