Smoking and anaesthesia Dr. S. Parthasarathy MD., DA., DNB, MD (Acu), Dip. Diab. DCA, Dip. Software...
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Transcript of Smoking and anaesthesia Dr. S. Parthasarathy MD., DA., DNB, MD (Acu), Dip. Diab. DCA, Dip. Software...
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 !!