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

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 FUNCTIONDURING 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 !!