Smoking and anaesthesia Dr. S. Parthasarathy MD., DA., DNB, MD (Acu), Dip. Diab. DCA, Dip. Software statistics- Phd(physio) Mahatma Gandhi Medical college and research institute , puducherry , India

history Morton said in 1890 s Smoking can cause postoperative pulmonary complications A general surgeon in 1944 – proved it after fifty years

What is it ?? Smoke is an heterogenous aerosol produced by the incomplete combustion of the tobacco leaf 21 % incidence One third smoke !! What does it contain ?? Smoke Gas particulate

80% to 90% gaseous nitrogen, oxygen,and carbon dioxide. carcinogens hydrocyanic acid and hydrazine, ciliotoxins, irritants such as hydrocyanic acid, acetaldehyde, ammonia, acrolein, and formaldehyde, and an agent impairing oxygen transport, namely carbon monoxide.

10 -20 % - Particulate nicotine. It also contains carcinogens such as tar and polynuclear aromatic hydrocarbons and tumor accelerators such as indole and carbazole.

Important for anaesthetists Gaseous – carbonmonoxide Particulate – nicotine

No mention about marijuana !!! Why should we discuss smoking and anaesthesia ??

Established !! increased respiratory complications during and after GA Surgical wound complication rates are higher in smokers, particularly following plastic and reconstructive surgery, bone surgery, bowel surgery and microsurgery. Smoking has adverse effects on the blood flow to tissues that may impair wound healing More ICU admissions Delayed discharges

Generally problematic ?? Why should we bother ?? Generally problematic ?? Then stop !!

Other facts if you stop?? Adding six to eight years to your life. Reducing your risk of lung cancer and heart disease. Reducing your loved ones’ exposure to second-hand smoke. Saving an average of Rs. _______ each year. Can purchase a few plots

Smoking on systems - Cardiovascular system Theft higher oxygen consumption through the sympathetic- adrenergic system activation. At the same time, there is decreased oxygen supply by increased COHb levels coronary vascular resistance increase risk factor for arterial thromboembolism and coronary vasospasm

On CVS – continued Resting catecholamine increase CO – hypoxemia Negative inotropy Increased viscosity Myocardial ischemia

CVS Nicotine – two phases of actions Initial stimulation CVS Ganglion blocking action – hypotension and neuromuscular paralysis

Respiratory system Increase mucus secretions. Decreased ciliary activity Laryngeal and bronchial reactivity is increased small-airway narrowing, causing an increased closing volume. Pulmonary surfactant is also decreased. Loss of elastic recoil – COPD FEV1 decrease 60 ml/year /// 20 ml/year Infections !!

Respiratory system Carboxyhaemoglobin levels maybe up to 15% in smokers. the affinity of carbon monoxide to Hb is 250 times greater than oxygen. This results in a reduction in the availability of oxygen binding sites and a reduction in oxygen carrying capacity. Left shift of the oxygen haemoglobin dissociation curve results in reduced oxygen delivery to the tissues. Bedside pulse oximeters -- Yes but no ?? !!

Smoking by virtue of mechanics and chemistry – prone for hypoxemia The same is true for anaesthesia Don’t add problems

Following smoking cessation ciliary activity starts to recover within 4-6 days. The sputum volume takes 2-6 weeks to return to normal. There is some improvement in tracheo bronchial clearance after 3 months. It takes 5-10 days for laryngeal and bronchial reactivity to settle.

But in simple terms Long term smokers – pulmonary dysfunction and hypoxemia Short term smokers -- reactive airway disease – spasm and hypoxemia Passive smokers also !!

See there !! Nicotine reaches the brain within seconds after inhalation. Long term tobacco smoking of more than fifty pack years carries a higher risk of post-operative admission to intensive care . The number of pack years is calculated by the number of packs smoked per day multiplied by the number of years smoked.

Bad things are short !! Short abstinence periods may influence results due to the relatively short nicotine (30 to 60 minutes) COHb (4 hours) elimination half-life.

Other systems Impaired humoral activity and cell mediated immunity leads to impaired immune response which results in increased risk of infection and malignancy. It also decreases immunoglobulins and leucocyte activity. Smoking also results in increased secretion of anti-diuretic hormone (ADH) leading to dilutional hyponatremia.

Other systems CNS stimulator Tobacco foetal syndrome Paediatrics – wheezing episodes

Preop work up Patients are advised to quit smoking at least four to six weeks prior to surgery. Abstinence for twelve hours is sufficient to get rid of carbon monoxide. Ciliary function improves and nicotine levels return to normal within 12-24 hours. Abstinence for 2 weeks helps return sputum volume to normal levels. Laryngeal and bronchial activity is better in 5-10 days. Improvement in small airway narrowing is seen in 4 weeks but it takes 3 months to see changes in tracheobronchial clearance.

But treat anxiety due to smoke withdrawal

Move on to anaesthesia

Preoperative objectives are based on secretions control, pulmonary function improvement stopping smoking several weeks before surgery

Stopping Smoking * Ideally, stop smoking for at least 8 weeks prior to surgery. * Stop for 24 hours before surgery to negate effects of nicotine and COHb. * If an operation is scheduled for the next morning, stop smoking the previous evening.

Keep preoperative disclosures confidential

Preparation * Treat lung infections such as chronic bronchitis. * Prescribe bronchodilators, breathing exercises, chest physiotherapy in symptomatic smokers. * Do blood gases to get baseline PaO2 and PaCO2 if a long operation is planned.

Underlying ischaemic heart disease and hypertension should be identified, and anaesthesia administered to minimize the risk from these factors. Routine investigations CxR, ECG, ECHO (SOS) PFT

Always consider Regional or local Even in spinal --------

THE EFFECT ON RESPIRATORY FUNCTION DURING SPINAL ANESTHESIA FEV1 decreased – spinal above T10. Forced mid expiratory flow decreased Accumulation of secretions Deep breath and cough during block !!

Drugs – enzyme induction smokers have increased requirements for opioids postoperatively. In a study of morphine requirements after cholecystectomy, Glasson et al. found that smoking significantly influenced the requirement for pethidine and morphine Increased fentanyl and increased complications Cause ?

Possible causes Administer more analgesics, needed due to i) anxiety from stopping smoking, (ii) decreased pain threshold, (iii) increased metabolism of the drug.

Drugs NSAIDs and paracetomol --- no effect smoking decreases the potency of aminosteroid muscle relaxants ?? Atracurium also affected Relevance ?? Scoline - ?? Rocuronium !! Nicotine -- down regulates NMJ receptors ?!

Drugs P450 induction , drugs and decreased PONV Theophylline , ropivacaine !!, enflurane and flouride levels Alcohol and cigarette smoke

Anaesthesia Preoxygenation IV induction – smooth IV lignocaine – smooth intubation Halo or sevo rocuronium No manipulation under light anaesthesia Increase MV to maintain ETCO2 No desflurane

Monitors Routine ECG ABG – PaCo2 -- ETCO2 – difference higher NMJ monitors

Recovery Extubate with adequate narcotics to prevent spasm episodes

Should I quit smoking permanently?? Yes -- better 50 % Vs 20 % complications if continued

increased blood viscosity and risk of postoperative deep venous thrombosis Some advocate Bupropion in the post op period as Nicotine replacement therapy

Epidural if there – continue Appropriate analgesia should be prescribed, particularly for abdominal or thoracic surgery where regional techniques such as epidural analgesia may have a role. Early mobilisation is important to improve lung function and sputum clearance. CHEST PHYSIOTHERAPY

Quitting causes cough ?? There is some misinformation with regard to deciding to quit smoking right before surgery. There is no data to support the contention that quitting too close to surgery may cause additional coughing. There also is no evidence of any other negative effects of quitting too close to surgery.

Proved compliance for anaesthesiologist s advice

Summary Heterogenous aerosol CO and nicotine Pulmonary , wound healing, ICU admissions Quit , anxiolytics, premed, prepare Regional, local then GA , intubation Deep – IV lignocaine, P450, narcotics, relaxants Increased MV , no desflurane Extubate without spasm Post op oxygen, physiotherapy , epidural ,

Thank you all Patients are compliant to us !!