Anesthetic consideration in smokers,alcoholics and addicts

ANESTHETIC CONSIDERATION IN

SMOKERS ALCOHOLICS

& DRUG ADDICTS

DR AFTAB HUSSAIN

Smoking

Smoking is a risk factor for intra operative pulmonary complications and a wide range of post-operative pulmonary, cardiovascular and wound related complications.

It is associated with poorer outcomes in patients.

Cigarette smoking causes cough, mucous hyper-secretion and airflow obstruction.

Passive smokers also have an increased incidence of adverse events.

Cardiovascular effect of smoking

Nicotine stimulates the adrenal medulla to secrete adrenaline.

It resets the aortic and carotid body receptor----- maintain a higher blood pressure.

Stimulates the sympathetic system.

Myocardial contractility is increased.

Decrease in the intracellular oxygen transport and utilization.

Negative ionotropic effect----- chronic tissue hypoxia.

Pulmonary effects of smoking

Irritants in smoke increase mucus secretion. The mucus becomes hyperviscous, with altered elasticity.

Cilia become inactive- impaired tracheobronchial clearance.

The integrity of the epithelium is lost --- result in increased reactivity.

Smoking leads to narrowing of small airways increase in closing volume.

There is also an increase in proteolytic and elastolytic enzymes leading to loss of elasticity and emphysema.

The risk of lung infection is increased. 25% of smokers suffer from chronic bronchitis.

Pulmonary effect of smoking

Carboxyhaemoglobin levels maybe up to 15% in smokers.

Carbon monoxide and oxygen both bind to the alpha chain of haemoglobin, but the affinity of carbon monoxide 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.

The half-life of carboxy-haemoglobin depends on pulmonary ventilation. At rest, the half-life is about 4-6 hours.

Effect of smoking on other system

Smoking has no effect on the gastric volume or the pH of gastric secretions.

Smoking relaxes the gastro-oesophageal sphincter but returns to normal within minutes after stopping.

Impaired immunity ----- increased risk of infection.

It also decreases immunoglobulins and leucocyte activity.

Smoking also results in increased secretion of anti-diuretic hormone (ADH)---- dilutional hyponatremia.

Benefits of smoking

Smoking is found to reduce risk of :

PONV

Ulcerative colitis

Schizophrenia

Deep vein thrombosis

Anaesthetic consideration

Patients are advised to quit smoking at least four to six weeks prior to surgery.

Abstinence for 12 hr. is sufficient to get rid of carbon monoxide.

Ciliary function improves -- 12-24 hours.

Laryngeal and bronchial activity is better-- 5-10 days.

Return sputum volume to normal levels– 2 weeks

Improvement in small airway narrowing is seen in 4 weeks but it takes 3 months to see changes in tracheobronchial clearance.

Anaesthetic consideration

Airway complications on induction, particularly during facemask ventilation or LMA insertion are common------ the need for intubation should always be anticipated.

Pre-oxygenation should be routine.

Adequate anaesthesia should be administered for intubation to minimise the risk of provoking bronchospasm.

Anaesthetic consideration

Regional anaesthesia has advantages for patients with long term respiratory complications of smoking.

Underlying ischaemic heart disease and hypertension should be identified, to minimise the risk from these factors.

Early mobilisation is important to improve lung function and sputum clearance.

ALCOHOLISM

Effect of Alcoholism

Vitamin deficiencies

Alcohol abuse is the leading cause of thiamine (vitamin B1) deficiency.

Wernicke’s encephalopathy, a syndrome characterised by the classic triad of encephalopathy,ophthalmoplegia and ataxia.

Metabolic abnormalities

Acidosis--- Up to 25% of patients with an alcohol use disorder will have metabolic acidosis on admission.

Effect of AlcoholismMagnesium

The main causes are poor dietary intake and increased urinary and faecal losses.

Phosphate

Hypophosphataemia arises as a result of increased renal excretion.

Rhabodomyolysis

non-traumatic rhabdomyolysis occurs in patients with alcoholism, especially after acute intoxication.

Effect of Alcoholism

Alcoholic liver disease

Alcoholic liver disease can be characterised alcoholic fatty liver, alcoholic hepatitis or alcohol-related cirrhosis.

Pancreatitis

Alcohol is the major causative factor of acute pancreatitis in about 32% of cases.

Immune dysfunction

Patients with AUD have a three to five-fold increased postoperative infection rate compared to nonalcoholic patients.

Effect of AlcoholismAlcoholic cardiac dysfunction

Chronic alcohol ingestion leads to alcoholic cardiomyopathy.

Increased risk of stroke and hypertension

Haemostatic disturbances

Evidence in the literature suggests both platelet activation and platelet inhibition by alcohol.

Pre-operative

Evidence suggests that a period of abstinence in the preoperative period decreases postoperative morbidity.

Extensive history.

Full physical examination, with special attention to cardiac and respiratory systems

Preoperative

CXR and ECG

Electrolyte and biochemical profile

Full blood count, INR and PT/PTT

Consider local or regional anaesthetic techniques.

Peri-operative period

Altered induction agent dose.

Rapid sequence intubation if acute intoxication.

Intraoperative - Lower MAC of inhaled agents in acute intoxication.

Careful opioid administration.

Peri-operative period

Paracetamol dose adjustment.

Muscle relaxants with organ independent metabolism.

Postoperative – Risk alcohol withdrawal syndrome.

Choose analgesia carefully.

Anaesthetic drugs

Propofol - Decreased dosing requirement in acute intoxication.

Increased dosing requirement in chronic alcoholism.

Thiopentone - Decreased dosing requirement in acute intoxication.

Anaesthetic drugs

Etomidate - No evidence of altered doses.

Neuromuscular Blocking agents- Altered pharmacokinetics with increased volume of distribution and decreased binding proteins in alcoholic liver disease.

Inhalation anaesthetics- Decreased MAC in acute intoxication.

Anaesthetic drugs

Decreased clearance of halothane in alcoholic liver dysfunction

Opioids - Decrease metabolism of morphine, pethidine and fentanyl in chronic alcoholism

Risk of accumulation with repeated doses.

Alcohol withdrawal syndrome

It is important for anaesthesiologists to know the symptoms, clinical signs and management of alcohol withdrawal symptoms.

One of the cause of post operative delirium.

Develop in alcohol dependant individuals within 6 to 24 hours from their last drink. It typically presents after 2 to 4 days of abstinence and can persist for up to two weeks.

Signs and symptoms of AWS

Early signs

Hyperpyrexia

Tachycardia

Hypertension

Diaphoresis

Later findings

Confusion

Agitation

Seizures

Psychosis

Autonomic hyper-reactivity

Drug abuse

As anesthesiologists we need to be aware of the use of illicit drugs impacts on anesthetic care.

Medical adverse effects range from pulmonary and cardiovascular effects, to irreversible brain damage.

May manifest or worsen under anesthesia.

Injected drugs and high-risk sexual behaviors are risk factors for the transmission of HIV/AIDS and hepatitis C.

Cannabis

Autonomic nervous system-- low or moderate doses --- an increase in sympathetic activity occurs with a reduction of parasympathetic activity

If high doses are ingested---- inhibition of the sympathetic activity but not of the parasympathetic activity

Marijuana causes increased myocardial depression and tachycardia.

Cannabis (contd.)

In patients with acute marijuana abuse, drugs increasing heart rate (such as ketamine, pancuronium, atropine and epinephrine) should be avoided.

Cannabis inhalation affects lung function.

In pregnant patients chronic use of marijuana may reduce uteroplacental perfusion- result in fetal IUGR.

Cocaine

Serious complications are associated with both regional and general anesthesia when administered to cocaine abusers.

Cocaine-induced thrombocytopenia can occur.

Regional anesthesia--- hemodynamic consequences of cocaine.

Cocaine (contd.)

Hypertension may occur, as well as hypotension, which may lead to cardiac arrhythmias.

Ephedrine-resistant hypotension may be encountered.

Patients under regional anesthesia may also show combative behavior and altered pain perception, due to changes in opioid receptor.

Cocaine (contd.)

Cocaine-abusing patients under general anesthesia may also exhibit hypertension and cardiac arrhythmias.

Severe hypertension may also occur--result of direct laryngoscopy in cocaine intoxicated patients.

Beta blockers, such as propanolol, are contraindicated in these patients.

Cocaine (contd.)

Volatile anesthetics may produce cardiac arrhythmias and increase the systemic vascular resistance in patients.

Halothane is avoided-- sensitizing effects on the myocardium to catecholamines.

Ketamine should be used with caution or avoided-- stimulate the CNS and increase catecholamine levels, potentiating cardiac effects.

Cocaine (contd.)

The combination of hypertension and proteinuria with or without seizures from their acute intake may be mistaken for preeclampsia or eclampsia.

Etomidate should also be used with caution because of possible myoclonus, seizures and hyperreflexia.

Cocaine (contd.)

Propofol and thiopental has proven to be safe in cocaine-abusing patients.

Rapid transplacental diffusion due to its solubility and high fetal-blood and -tissue cocaine levels.

Decreased uteroplacental blood flow may lead to uteroplacental insufficiency, acidosis, hypoxia and fetal distress.

Opioids

Opioid antagonists or agonist–antagonists administered ,must be avoided in addicts---precipitate acute withdrawal syndrome.

Treated with clonidine, replaces opioid-mediated inhibition.

The withdrawal syndrome may be reversed by administration of an opioid or methadone.

Opioids

Regional anesthesia can be administered safely to these patients. An increased tendency for hypotension, should be anticipated.

It has been reported that these patients have an increased incidence of spinal, epidural and disc-space infection.

Opioids

Opioid addicts may have difficult peripheral and central venous access.

Sepsis, coagulopathy and hemodynamic instability increase the risk associated with general anesthesia.

May have concomitant liver disease, malnutrition and reduced intravascular fluid volume which may require adjustments in anesthetic drug doses.

Opioids

Chronic opioid abuse leads to cross-tolerance of anesthetic drugs, usually a result of chronic receptor stimulation.

Postoperatively, due to decreased pain tolerance secondary to decreased production of endogenous opioids, these patients may experience exaggerated pain.

Hallucinogenic drugs

The hallucinogen group of drugs includes lysergic acid diethylamide (LSD), phencyclidine (PCP), psilocybin and mescaline.

They activate the sympathetic nervous system by causing hypertension and tachycardia, increase body temperature and dilate pupils.

Hallucinogenic drugs

The effects of acute ingestion develop over 1–2 hr and last for approximately 12 hr.

Wide swings in blood pressure and tachycardia.

Increased risk of cardiomyopathy, coronary and cerebral vasospasm.

Hallucinogenic drugs

Sympathomimetic stimulation effects, extreme caution when using vasopressors such as ephedrine.

Hallucinogens may prolong the analgesic and ventilatory depressant effects of opioids.

In parturients, these amphetamine-like medications may pose a problem from their initial presentation.

Solvents

Inhalants include a variety of substances, such as organic solvents and volatile agents, that affect the CNS.

Toluene is the most commonly used solvent and a major component of household paints, glue, rubber cement and cleaning agents.

These drugs can be sniffed or ingested orally.

Solvents

Patients are at an increased risk of developing cardiac arrhythmias due to autonomic cardiac dysfunction caused by the abuse of these solvents.

Myocardial infarction and labile blood pressures might also be encountered.

In acutely intoxicated patients, general anesthesia is sometimes the best option.

Solvents

Pulmonary complications may reflect increased airway resistance.

When regional anesthesia is considered, it is important to consider the patient’s altered perception and combative behavior.

Distal and proximal acidosis could be of concern in these patients

Conclusion

Smoking ,alcoholism and substance abuse remains one of the biggest societal problems around the world despite education on prevention and rehabilitation of illicit drugs.

Anesthesiologists should be aware of this problem and the most likely effects and potential risks associated with the abuse of these substances.

Some of these patients may present at preadmission testing, emergency situations (even critical care) or in the obstetric suite for anesthesia or analgesia.

Thank you.

Due to the diverse clinical presentations that may arise from there abuse, the anesthetic management should be tailored to each individual and universal precautions should always be followed when providing care.