Cannabis and surgery: a no-go?

On several occasions, patients have been denied surgery because of their cannabis use. What are the medical and non-medical reasons that justify such a refusal?

Potential problems

Cannabis is often smoked in the form of a joint. It can therefore cause respiratory complications just like cigarettes. In a recent study In a study involving 50 patients, 26 of them required albuterol, a medication used to dilate the airways, and 31 of them required glycopyrrolate, a medication that prevents excessive saliva production. Both of these medications are used to prevent breathing difficulties and facilitate intubation.

«These problems are common to all chronic smokers,» explains Dr. Hervé Damas, a surgeon who also specializes in cannabis-based treatments. Thus, the problem is not cannabis itself but the method of consumption. Nevertheless, the same study highlights that cannabis appears to interfere with anesthetics. In this regard, it concurs with another study which, after comparing the medical records of anesthetized patients, concluded that patients who use medical cannabis required significantly higher doses of anesthetics—particularly propofol—during surgery.

Another study suggests that cannabis use may also lead to cardiovascular complications, particularly among young chronic users, by increasing the risk of myocardial infarction by 2.5 to 4 times. That said, the generalizability of these findings has been challenged. Given these risks, cannabis use leads to the use of more medications during surgery, thereby increasing the risk of adverse side effects associated with these medications. In general, doctors recommend stopping use at least 72 hours before any surgery.

Moral barriers remain

While cannabis use does carry some additional risks in surgery, these do not appear to justify canceling the operation. However, there have been cases where doctors have refused to perform surgery after being informed that the patient uses cannabis. Last June, a Scottish patient and medical cannabis advocate, Bernadette McCready, who uses cannabis oil to relieve chronic pain following a hysterectomy, was denied surgery at the Royal Alexandra Hospital for that reason.

«I was sitting on the edge of the bed, just a few minutes before the operation, when I was thrown out of the hospital,» she explains to Daily Record. «It was as if there was a serial killer in the room. I’ve never felt so humiliated.» This kind of refusal is based on purely moral considerations. British public health authorities have stated that the possession or use of cannabis does not justify such a refusal: «Our policy is to provide care to everyone, regardless of lifestyle choices, except in very specific clinical circumstances.».

Unfortunately, this is not an isolated case: in Utah, before cannabis was legalized, A 19-year-old man was denied placement on a lung transplant list because of his past cannabis use. He was forced to go to a hospital in Pennsylvania where doctors are prohibited from denying a transplant based on cannabis use. When asked by the local press about this case, a surgeon at the hospital stated, «We have recently relaxed our criteria regarding cannabis.».

In a survey In a survey of 360 heart transplant centres across 26 countries, almost two-thirds of respondents were in favour of admitting patients who use medical cannabis onto transplant waiting lists. By contrast, only 27.5 per cent of them support the admission of recreational cannabis users. Such moral barriers can lead patients to conceal their cannabis use from doctors. This can be dangerous, as doctors are unable to anticipate potential complications associated with such use. Communication is essential. This is all the more important given that the majority of respondents in this study (68 per cent) support transplantation if the patient has abstained.