Transcript Smoking and anaesthesia mgmc

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
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 sympatheticadrenergic 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 antidiuretic
hormone
hyponatremia.
(ADH)
leading
to
dilutional
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,
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 !!