Priapism Cavernous Blood Gas Classification
Classifies a priapism episode from the cavernous blood gas, which separates two conditions treated in opposite directions.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- pO2 in blood drawn from the corpus cavernosum
- 12 mmHg
- pCO2 in blood drawn from the corpus cavernosum
- 78 mmHg
- pH in blood drawn from the corpus cavernosum
- 7.05
- Hours since the erection began
- 30 hours
- Perineal or straddle trauma before onset
- Yes
- Sickle cell disease
- Yes
Result: ischemic, at 30 hours
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What the result means
- pO2 under 30, pCO2 over 60, pH under 7.25
- Ischemic priapism. A compartment syndrome of the erectile tissue, decompressed rather than observed.
- pO2 over 90, pCO2 under 40, pH near 7.40
- Non-ischemic priapism. An unregulated arterial inflow, usually painless and not an emergency; aspiration and a sympathomimetic treat the other type.
- A gas in between
- Color duplex decides: absent or minimal cavernosal arterial flow is ischemic, normal or high flow is non-ischemic.
- Nothing decisive
- Handled as ischemic until it is shown not to be, because that is the type where waiting costs erectile tissue.
- A trauma history
- Does not classify the episode. It is the classic story for the non-ischemic type and the classic reason an ischemic one is watched instead of decompressed.
- Under 4 hours
- Inside the window before an ischemic episode becomes a compartment syndrome.
- 4 to 24 hours
- A compartment syndrome. Necrosis of the cavernous smooth muscle begins around 24 hours.
- Past 36 hours
- Erectile function is rarely preserved. Intervention is for pain and detumescence rather than for potency.
- Sickle cell disease
- Does not change the acute treatment. Systemic care must not delay or replace the local intervention.
What you enter
- pO2 in blood drawn from the corpus cavernosum
- pCO2 in blood drawn from the corpus cavernosum
- pH in blood drawn from the corpus cavernosum
- Hours since the erection began
- Color duplex finding, if done
- Perineal or straddle trauma before onset
- Sickle cell disease
How this is calculated
Citation
Bivalacqua TJ, Allen BK, Brock GB, et al. The diagnosis and management of recurrent ischemic priapism, priapism in sickle cell patients, and non-ischemic priapism: an AUA/SMSNA guideline. J Urol. 2022;208(1):43-52. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.