Smoking cigarettes before surgery can increase the risk of severe complications. Some complications carry a risk of death.

In some extreme cases, doctors may refuse to operate on people who smoke.

Experts recommend that people undergoing surgery, especially cases requiring general anesthesia, quit smoking before the procedure. Quitting lowers the risk of certain complications affecting lung or heart health.

This article discusses what happens if someone smokes before surgery, how smoking interacts with anesthesia, and when someone should stop smoking before surgery.

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In a 2021 study, researchers analyzed data from more than 328,500 people who underwent surgery in 2012–2019 in Michigan. Researchers found that 1 in 4 people smoked at the time of their surgery.

Cigarette smoke contains more than 4,500 chemicals, most of which can harm human health. Smoking before surgery can increase someone’s risk of experiencing complications during and after surgery.

Some of these may be life threatening.

Potential complications include:

Breathing problems and lung infections

Smoking can prevent the lungs and heart from functioning to their full extent. This impairment can translate into breathing problems during or after surgery.

Tobacco smoke can also damage the lungs and increase the risk of:

  • pneumonia
  • lung collapse
  • needing to use a ventilator after surgery, this is a machine that breathes for someone

Heart problems

Smoking is a major risk factor for developing and dying from heart disease.

The chemicals found in cigarette smoke, such as nicotine and carbon monoxide, can greatly increase someone’s risk of developing heart-related complications, such as heart attack and stroke, during or after surgery.

Bone, joint, and muscle problems

According to the American Academy of Orthopedic Surgeons, smoking can harm the health of bones, joints, and muscles, resulting in poorer outcomes from orthopedic surgery.

Broken bones do not heal as quickly in people who smoke. Nicotine impacts the body’s production of cells that are involved in making bone.

People who quit smoking tend to have improved outcomes after surgical treatments for musculoskeletal injuries and conditions.

Weakened immune system

Smoking weakens the immune system’s strength, making it much harder to heal after surgery and increasing the risk of developing infections.

Scarring or implant problems

People who smoke are more likely to experience scarring and lose implants inserted during certain procedures, such as breast reconstruction.

According to the American Society of Anesthesiologists, smoking can increase the risk of anesthesia complications. Specifically, it can lead to:

  • increased risk of respiratory events, such as chest infection
  • longer stays in the recovery room following the procedure
  • needing more anesthetic, which increases the risk of any associated anesthesia complications

Quitting smoking before undergoing anesthesia seems to greatly reduce the risk of complications after surgery. A 2011 study found every subsequent tobacco-free week can improve health outcomes following anesthesia procedures by 19%.

The World Health Organization (WHO) reports that not smoking for at least 4 weeks is consistently associated with better outcomes after surgery.

The American Society of Anesthesiologists states that quitting smoking as soon as the day before surgery can reduce someone’s risk of complications.

While quitting immediately before surgery may be beneficial, quitting 1 week or more ahead of surgery is better. Quitting as soon as possible would be most beneficial. Many experts suggest quitting 4–8 weeks before surgery.

Some research indicates quitting smoking more than 8 weeks before surgery can reduce the rate of pulmonary complications from 48% to 20%.

Studies also show that the longer someone abstains from smoking before surgery, the less likely they are to experience complications overall.

Some evidence suggests that quitting immediately before surgery can have disadvantages:

  • Increased mucus production and airway reactivity can interfere with breathing.
  • Nicotine withdrawal can increase the risk of sleep problems, irritability, restlessness, and depression.
  • Quitting smoking can increase feelings of being unable to handle stress.

Smoking while recovering from surgery can increase the risk of heart attack or heart problems.

Smoking after surgery also reduces blood flow, interfering with the body’s healing process. The slower wounds heal, the more likely they are to become infected.

Infected wounds can cause serious complications if the infection becomes severe or spreads throughout the body. These complications include systemic shock, coma, and death.

According to the WHO, smoking even one cigarette reduces the body’s ability to transport nutrients necessary for healing.

However, quitting smoking at least 4–6 weeks before surgery and staying tobacco-free for 4 weeks after surgery can reduce the likelihood of wound complications by 50%.

Several national organizations and services can help people quit smoking and provide support. Many of them offer free services, including:

  • Quitlines: Get free assistance by calling 800-QUIT-NOW (800-784-8669). It connects people to a confidential, trained counselor who can help people start their quitting journey. They can also provide medications, such as nicotine replacement therapy gums or patches.
  • American Lung Association: The American Lung Association offers numerous services and programs to encourage and support people quitting smoking.
  • American Cancer Society: People can find detailed information on how to quit smoking. The organization also operates a hotline at 800-227-2345.
  • Centers for Disease Control and Prevention (CDC): The CDC offers extensive government and professional resources to help people quit smoking.
  • American College of Surgeons: People can find detailed instructions for preparing for quit day, including how to handle nicotine withdrawal, and more.

The body begins to heal as soon as someone stops smoking.

Immediately after quitting smoking, the lungs and heart return to normal functioning levels. Nicotine and carbon monoxide levels decrease, which can improve the postsurgical healing process.

According to the American College of Surgeons, the timeline after someone quits smoking is as follows:

  • 48–72 hours after quitting: Mucus secretions in the airways increase and the airways become more reactive, which may result in a cough. Blood oxygen levels increase and blood carbon monoxide levels drop. The amount of nicotine in the blood and tissues drop, as does any increase in heart rate (tachycardia).
  • 2–4 weeks after quitting: Mucus secretion in the airways begins to reduce, and airways become less reactive. Tiny hairs that line the respiratory tract (cilia) reactivate and begin to move mucus out of the airways.
  • 4–6 weeks after quitting: Metabolic and immune function begin normalizing.
  • 8 weeks after quitting: The risk of postsurgical complications and death decreases.
  • 12 weeks after quitting: Cilia activity and small airway function return to normal.

Smoking before surgery increases the risk of experiencing lung, heart, and immune system complications during and after surgery.

Smoking after surgery can also interfere with the body’s healing process, which increases the risk of severe infections, coma, and death.

Most health authorities suggest that people quit smoking as soon as possible, or at least 4–8 weeks before surgery, and to abstain from tobacco for at least 4 weeks after surgery.

Many resources are available to help people quit smoking and support them during the process. If someone has trouble quitting, they can seek assistance from a doctor or other healthcare professional.