Cigarette Smoking and Anesthesia - Effects and Management

Introduction

Smoking is widely recognized for causing serious health problems, including heart disease, asthma, and lung cancer. When undergoing surgery, especially with general anesthesia that induces unconsciousness, complications related to smoking and anesthesia can arise. For individuals who smoke and are preparing for surgery, anesthesiologists recommend quitting smoking well in advance of the procedure. It is essential to have a conversation with the anesthesiologist about smoking habits and how it could impact the anesthesia care plan. Anesthesiologists are specialized medical doctors trained in anesthesia, pain management, and critical care medicine.

Why Is It Necessary to Stop Smoking Before Surgery?

Smoking impairs the proper functioning of the heart and lungs. This can lead to difficulties in breathing before or after surgery and increase the risk of developing pneumonia. Smokers are more likely to require a ventilator or a breathing assistance machine after surgery. Moreover, smoking reduces blood flow, delaying the healing process and raising the likelihood of infection in the surgical incision. As a significant contributor to heart disease, smoking also elevates the risk of experiencing a heart attack during or after surgery.

What Are the Anesthetic Drug Requirements in Smokers?

In smokers, there are numerous harmful substances found in cigarette smoke, with nicotine and carbon monoxide being the most well-known. These substances, including nitrogen oxides and toxins, can affect the body's response to anesthesia.

Smoking leads to increased metabolism and liver enzyme activity, causing smokers to need higher doses of pain-relieving medications. Specific drugs like Pethidine and Morphine are affected by smoking, requiring dosage adjustments. While the effects of medications like Paracetamol and NSAIDs remain the same, aminosteroid muscle relaxants become less potent in smokers.

Exposure to anesthesia gases can result in liver and kidney problems. The risk is connected to the duration of exposure, the concentration of the gas, and how the body metabolizes it, although quantifying this risk precisely is challenging. These factors highlight the importance of considering a patient's smoking history when planning anesthesia for surgery.

• Post-operative Nausea and Vomiting (PONV) In Smokers: Post-operative nausea and vomiting (PONV) tend to occur less often in people who smoke. This is partly because tobacco smoke prompts the production of certain enzymes, like cytochrome P450, which provides some protection against PONV. Continuous exposure to nicotine can also make the body less sensitive to the nausea-inducing effects of surgery and anesthesia.

• Pre-operative Assessment and Smoking Cessation: Before undergoing surgery, patients are advised to stop smoking at least four to six weeks beforehand. Just twelve hours of not smoking can remove carbon monoxide from the body. Ciliary function, which helps clear the airways, improves, and nicotine levels return to normal within 12 to 24 hours. Two weeks of not smoking brings sputum production back to regular levels, while improvements in the function of the larynx and bronchial passages are seen within five to ten days. It takes about four weeks to notice improvements in the narrowing of small airways and three months for changes in the clearance of the tracheobronchial passages. Interestingly, quitting smoking can worsen asthma symptoms, and short-term cessation raises the risk of laryngospasm and bronchospasm during anesthesia. Stopping smoking can also lead to feelings of anxiety and withdrawal symptoms.

• Post-operative Complications: Smoking is a significant risk factor for postoperative lung problems. Smokers are more susceptible to postoperative atelectasis, which can slow down recovery and make patients more vulnerable to pneumonia. Additionally, there is a higher likelihood of needing intensive care after surgery among smokers.

What Is the Management of Anesthesia in Smokers?

Managing anesthesia in smokers involves specific steps to ensure a safe procedure:

• Stopping Smoking:

  • Ideally, quit smoking for at least eight weeks before surgery.

  • Refrain from smoking 24 hours before surgery to counter the effects of nicotine and carbon monoxide.

  • If surgery is scheduled for the next morning, stop smoking the evening before.

• Preparation:

  • Address lung infections like chronic bronchitis.

  • Provide bronchodilators, breathing exercises, and chest physiotherapy for symptomatic smokers.

  • Conduct blood gas tests for baseline oxygen and carbon dioxide levels if the operation is lengthy.

• Choice of Technique: Prefer local or regional anesthesia over general anesthesia to minimize risks.

• Premedication:

  • Use medications like Glycopyrrolate to reduce secretions.

  • Administer anxiolytic agents such as Midazolam to alleviate the psychological effects of quitting smoking.

  • Administer nebulized Lignocaine before surgery to prevent respiratory issues during anesthesia.

General Anesthesia:

• Induction:

  • Preoxygenate to reduce carbon monoxide levels.

  • Use any suitable intravenous induction agent. Intravenous Lignocaine can prevent laryngospasm during intubation.

  • For volatile agent induction, prefer Sevoflurane or Halothane.

  • Avoid light anesthesia to prevent complications like coughing or breath holding.

• Intubation: If nebulized Lignocaine is not given, spray with Lignocaine before intubation to numb the larynx and reduce hyperreactivity.

• Maintenance:

  • Avoid Desflurane, which can irritate the respiratory system in chronic smokers.

  • Increase the minute volume to maintain normal carbon dioxide levels.

• Monitoring:

  • Be aware of potential overestimation of oxygen saturation when using pulse oximeters.

  • Use a CO oximeter for accurate oxygen saturation measurement.

  • Monitor the electrocardiogram, especially in patients with heart disease, to detect any arrhythmias.

  • Utilize a peripheral nerve stimulator to monitor neuromuscular blocks.

  • Conduct intermittent blood gas analysis in long operations to monitor carbon dioxide levels.

• Recovery: Avoid extubation under light anesthesia to prevent coughing, breath holding, laryngospasm, or bronchospasm.

Postoperative Period:

• Provide oxygen in the recovery room, during transportation, and for a period in the ward to support proper oxygenation.

• Administer additional analgesics postoperatively. Smokers may require more pain relief due to anxiety resulting from quitting smoking, reduced pain tolerance, and increased drug metabolism.

• Encourage breathing exercises and chest physiotherapy for symptomatic smokers to enhance lung function and respiratory recovery.

What Is the Role of Anesthesiologist in Advising Smokers?

In recent years, medical professionals, particularly anesthesiologists, have taken a more active role in encouraging smokers to quit before surgery. For instance, one study recommended patients abstain from smoking for five days before their operations, even though not all patients followed this advice strictly. However, many did reduce or quit smoking before the procedure after receiving verbal advice from anesthesiologists.

During anesthesia, anesthesiologists have experimented with taped messages advising patients to quit smoking, which has shown some success. In certain studies, patients decreased their cigarette consumption, and some quit altogether. Another study reported an eight percent success rate in patients quitting smoking after six months. Interestingly, those who underwent major surgery and smoked fewer than ten cigarettes a day were more likely to quit. Anesthesiologists should continue to advise patients to quit smoking during postoperative ward rounds, especially for patients who face smoking-related issues during anesthesia. Patients tend to be more compliant in such situations, making it a valuable opportunity to encourage them to quit smoking.

Conclusion

In summary, addressing smoking habits before surgery is crucial due to its detrimental impact on anesthesia and postoperative outcomes. Smokers face increased risks, including compromised lung function, delayed healing, and higher chances of complications like pneumonia. Anesthesiologists play a vital role in advising smokers, providing guidance on quitting, and tailoring anesthesia techniques to mitigate risks. Anesthesiologists should seize opportunities, especially during postoperative rounds, to counsel patients, leveraging their compliance after the surgery, ultimately contributing to improved surgical outcomes and overall patient health.