Can anaesthesia cause an involuntary erection?
Neither the European nor the American guideline describes erections caused by anaesthesia. They do cover erections that happen without sexual arousal, such as those during sleep, and erections that will not subside, called priapism. When the common ischaemic type of priapism lasts beyond four hours it is a medical emergency, and first treatment resolves 80% to 100% of cases.
Do the guidelines address erections during anaesthesia?
Neither the European guideline on sexual and reproductive health nor the American guideline on erectile dysfunction discusses erections that occur during general or regional anaesthesia. They give no rate for such erections and no advice on managing them in the operating theatre.
The European guideline mentions anaesthesia only in other settings, such as numbing the penis before treatment for priapism. Questions about erections during a specific operation are therefore answered by the surgical and anaesthetic team rather than by these guidelines.
Why can erections happen without sexual arousal?
Erections also occur during sleep, without sexual arousal. Doctors use this to check the physical erection mechanism with an overnight test that records how many erections occur, how much the penis swells, how rigid it becomes and how long each erection lasts, on at least two separate nights.
A firm erection lasting ten minutes or more during sleep shows that the mechanism itself works. Men whose erectile dysfunction is mainly psychological usually have normal results on this test, which is why it helps separate physical from psychological causes.
When does an erection that will not go down need urgent care?
Priapism is a persistent or prolonged erection without sexual stimulation that fails to subside. Ischaemic priapism, where blood is trapped in a rigid penis, accounts for more than 95% of episodes, and once it lasts beyond four hours the erectile tissue starts to lose its blood supply. Emergency treatment is then needed to prevent tissue death, scarring and permanent erectile dysfunction.
"Ischaemic priapism is a medical emergency and immediate intervention is mandatory." Source 1, p. 119
Irreversible damage to the erectile tissue begins to develop about 48 hours after onset, and the duration of the episode is the strongest predictor of lasting erectile dysfunction.
How is priapism treated if it lasts a long time?
Drawing the trapped blood out through a needle, combined with an injection of a drug that narrows the blood vessels, is the standard of care and resolves 80% to 100% of cases. Medical treatment is variably effective when priapism has lasted less than 48 hours, and treatment started after 48 hours relieves the erection but has little documented benefit for long-term erections.
A penile implant is discussed when presentation is delayed beyond 48 hours or when the episode does not respond to injections and shunt surgery. In that setting, the type of implant is chosen according to the patient, the surgeon's experience and the availability and cost of equipment.