How Marijuana Can Affect Your Surgery
Scott Sundick, MD, is a board-certified vascular and endovascular surgeon. He currently practices in Westfield, New Jersey.
If you smoke marijuana and are planning to have surgery you may be wondering if you need to stop smoking before your procedure. Like smoking cigarettes, the short answer is this: Yes, quitting today may improve your surgical outcome, how quickly you get out of the hospital, and how quickly you heal after surgery.
Marijuana Before Surgery
Like nicotine, marijuana can complicate surgery and should be avoided in the weeks and even months prior to your procedure. Much like smoking cigarettes, abstaining from marijuana in the weeks before surgery can decrease the likelihood of complications during and after surgery.
Unfortunately, research on the topic of marijuana use and the effects during surgery is limited. It should become more plentiful in the future as medicinal marijuana has been legalized in multiple states (and recreational use in a growing number), making it easier to gather scientific data on the topic.
We do know that marijuana, while effective for decreasing nausea and some other health-related benefits, has the potential to interact with anesthesia.
Risks of Smoking Marijuana
Contrary to popular wisdom, marijuana smoking is not a healthier option than cigarettes. It can lead to lung cancer and other respiratory problems.
The process of inhaling large amounts of marijuana, then holding it in the lungs for extended periods of time to increase the amount absorbed, leads to increased exposure to cancer-causing chemicals.
The chronic coughing, wheezing and difficulty breathing that long-term cigarette smokers experience also occur in marijuana users.
Types of Marijuana
When talking about surgery anesthesia and marijuana, all types of marijuana should be avoided. That means smoking marijuana, edibles, and synthetic marijuana.
Synthetic marijuana, in particular, is poorly understood, unregulated, and highly variable in content. For this reason, it is impossible to predict the reaction that might occur with exposure to anesthesia. Synthetic marijuana should not be used in the days, or even weeks, prior to surgery.
Marijuana and Anesthesia
Smoking marijuana regularly leads to the same risks of complications faced by patients who smoke cigarettes. This means that marijuana smokers are more likely than non-smokers to be on the ventilator longer, have a higher risk of developing pneumonia after surgery, and greater scarring of incisions.
The use of marijuana, especially immediately prior to surgery, can change the doses needed for sedation. One commonly used medication, propofol, requires substantially higher doses for the patient who routinely uses marijuana.
One study looked at the doses of propofol required to intubate patients who routinely smoked marijuana with non-marijuana using patients. The individuals who used marijuana required a dramatic increase in sedation.
One patient who smoked marijuana 4 hours prior to surgery was the topic of a case study, after experiencing an airway obstruction during the procedure. This is a very serious complication that can lead to death, and is believed to have been caused by airway hyperreactivity, a condition known in cigarette smokers but previously unidentified in marijuana users.
It is also believed that regular users of marijuana—whether it is smoked or eaten—are more likely to experience agitation.
Marijuana Effects During Surgery
The use of marijuana the day before surgery, and especially in the hours prior to the procedure, can cause more dramatic effects. While some people are tempted to use marijuana prior to surgery in an effort to relax or be less stressed before the procedure, this is a very bad idea and can cause problems.
Marijuana causes the blood vessels of the body to relax, a process called vasodilation. This process can cause the blood pressure to fall and the heart rate to increase. These, in turn, can complicate matters if the patient’s blood pressure is falling due to issues with the surgery, and can change the way the body responds to anesthesia.
Tell the Truth About Marijuana Use
It is very important that you are candid with the anesthesia provider about your personal use of marijuana. This means giving an accurate report of how much and how often you use marijuana, whether you eat it or smoke it, and when you last did so.
It is unlikely that your use will delay your surgery, but it is important that the anesthesia provider understands the potential for your body to need more anesthetic than is typical.
The anesthesia provider also needs to be prepared for any airway issues that may arise, which are more common in smokers of all types compared to non-smokers.
Regular marijuana use, like cigarette and cigar use, can increase the length of time it takes to be removed from the ventilator after surgery. The risk of being on the ventilator long term is decreased by quitting smoking before surgery, and that risk is decreased further with every day that passes between the last day of smoking and the day of surgery.
A Word From Verywell
It may seem like a drag—pardon the pun—to stop smoking marijuana before surgery and to not smoke during your recovery from surgery, but you will heal faster, return to your normal activities more quickly, have less scarring and fewer complications if you refrain.
It is true that most people would have quit smoking long ago if it were easy, but surgery offers a real incentive to back away from the marijuana (and nicotine) in order to have the best possible outcome after surgery.
Every day you go without smoking prior to surgery will decrease your chances of being on the ventilator longer than the average patient, and will decrease the length of your stay in the hospital.
Smoking pot before surgery can cause problems during and after your procedure, find out why you should avoid marijuana before surgery.
No eating, no drinking, and now, no marijuana before surgery, doctors say
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Patients planning to go under the knife have long heard that they should avoid eating or drinking for several hours before the surgery, but now doctors have another directive: No marijuana.
Cannabis consumers often need higher doses of anesthesia to become sedated and stay unconscious, recent studies show, and more anesthesia can in turn lead to an increased risk of complications.
But by no means, doctors said, should patients respond to this news by being anything less than honest with clinicians about their marijuana use.
“We’re not going to have any judgment — there’s no stigma,” said Dr. David Hepner, an anesthesiologist at Brigham and Women’s Hospital. “It’s just important for us to know, because the cannabis could interact with the anesthetic and we need to know how to adjust.”
The riskiest time for patients to undergo anesthesia is in the hour or two after pot consumption, Hepner said. Being high on marijuana raises a person’s heart rate and decreases blood pressure. Patients who get high before being sedated, which also affects the heart, could face increased risk of cardiac problems, including heart attack, Hepner said. A patient who just smoked pot could also suffer breathing issues because of heightened airway sensitivity.
“Most of those conditions, in the worst case scenario, may lead to death,” Hepner said. “I’m not saying that it’s very common, but the potential is there.”
For people who consume cannabis in the days or weeks prior to surgery — but not the day of the procedure — the risks seem less severe, Hepner said, although research is scant.
One small study in a Colorado hospital, published in May in the Journal of the American Osteopathic Association, found that pot consumers needed more of several common types of anesthetics — an average of 14 percent more fentanyl, 20 percent more midazolam, and 220 percent more propofol — during endoscopic procedures than noncannabis users. Propofol is generally safe, but increased doses could lower blood pressure, which could lead to deadly complications if untreated.
With marijuana restrictions loosening around the country, hospitals are grappling with how to handle surgery patients who say they recently consumed pot. Though marijuana has been the most commonly used drug in America for decades, doctors are only now beginning to understand the implications of mixing it with anesthesia.
In the past, anesthesiologists may have assumed patients’ unexpected reactions were due to issues unrelated to cannabis, but now they have more awareness of pot’s prevalence in the population and its effects, said Dr. John Alexander, an associate professor of anesthesiology at the University of Texas Southwestern who published a July research review in Baylor University Medical Center Proceedings.
“It’s just more top of mind now,” Alexander said. “It’s probably something we just didn’t think to ask about, especially because we didn’t know what to ask or what to look for.”
Patients also seem to be more open about their marijuana use. Brigham and Women’s Hospital has been asking patients whether they use cannabis for years, Hepner said, but he has noticed that more patients say “yes” now that pot is legal. That mirrors trends in other states with legally available cannabis, which doctors believe is due to both more consumption and reduced stigma.
Research is lacking, Alexander said, because federal prohibitions against marijuana use make it nearly impossible to fund or conduct rigorous clinical trials. The American Society of Anesthesiologists has urged the federal government to reclassify marijuana to allow medical studies.
Because of the lack of data, Alexander said, it’s not clear what happens in the bodies of cannabis users to make these abnormalities occur, or what role tolerance, withdrawal, and other factors may play.
Hepner said one explanation may be that marijuana use affects the central nervous system in a way that alters the body’s reaction to anesthetics, though research has not yet explored that.
The dearth of research also means that no clear guidelines exist, Alexander said, creating a wide range of responses by doctors and hospitals to cannabis-consuming patients.
Sometimes that leads to trouble. Jana Martin, 44, of Whitman, said she was scheduled for knee surgery in February at Brockton Hospital to address her torn cartilage, which caused shooting pain with every step. When a nurse called before the surgery, Martin said, she disclosed that she planned to consume medical marijuana the day of the procedure to treat her crippling anxiety and bipolar disorder.
The nurse advised against it, and they argued for a few minutes, Martin said, before the nurse told her to go ahead, as long as she was honest with her doctors that day.
Because of the stress of surgery, Martin said, “it would probably be the worst possible time” to not use cannabis. “It’s like asking somebody not to be nervous on their wedding day. It’s not about getting high — it’s medicine.”
The day of surgery, she said, she vaped some cannabis oil, then waited in the hospital for several hours before the surgical team was ready. Martin said that when she disclosed to the anesthesiologist that she had vaped hours earlier, the doctors canceled her surgery.
“I was so angry,” said Martin, who recently shared her story with the Cannabis Control Commission. “I felt like my rights had been violated.”
Lorraine McGrath, a spokeswoman for Signature Healthcare, which runs Brockton Hospital, said the organization doesn’t comment on patients’ cases due to federal privacy laws.
At Brigham and Women’s Hospital, Hepner said, clinicians would likely delay surgery, if it’s not an emergency, by at least two hours if a patient had just smoked or vaped cannabis, though the decision would be up to the anesthesiologist, in consultation with the surgeon and the patient.
But if the patient has eaten a pot edible, he said, that would lead to an eight-hour delay for the same reason that all food must be avoided for eight hours prior to surgery — to prevent the risk of aspiration pneumonia, a serious condition that can occur when recently eaten food is inhaled into the lungs.
Another important consideration: Research suggests that marijuana consumers may have increased sensitivity to pain following surgery. While some patients have found pot to decrease chronic pain, doctors say the drug may exacerbate more acute forms of pain. To address that problem, Alexander said, doctors can use multiple pain medications, including injections of a local anesthetic to numb the surgery site. Cannabis consumers may still need more opioids and other painkillers than noncannabis consumers, Alexander said.
“We’ve got slivers of information,” Alexander said, but he hopes future research will change that. “It’s a growing population and we want to know how best to take care of these patients.”
Cannabis consumers often need higher doses of anesthesia to become sedated and stay unconscious, which could increase the risks of complications, doctors say.