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Indian Society Of Anaesthesia North Parur & Mid West Kerala

PATIENT CORNER

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PATIENT HELPLINE

Smoking and Anaesthesia

Smokers are often told to stop smoking at least temporarily, before undergoing surgery and anaesthesia. The question is-Is it beneficial to quit smoking for a short period? If so, how long does the patient actually have to abstain in order for to have any benefit benefit?

It is well accepted that smoking is a health risk whether or not a patient is having surgery or anaesthesia in the future. There are significant and well-documented risks that should motivate anyone to quite smoking whenever possible.

EFFECT OF SMOKING
Smoking does two things in terms of the cardiovascular system that anaesthesiologist area concerned about. First, nicotine increases the amount of oxygen requirement of the body. Second smoking increases the amount of carbon monoxide attached to hemoglobin in the blood. This has the effect of decreasing oxygen supply available to the body. Carbon monoxide also decreases the pumping function of the heart thus decreasing the amount of oxygen that is delivered to the body. Therefore, oxygen supply is being compromised at the same time that more oxygen is being utilized.

The lungs are also affected by smoking. Smoking causes an increase in the amount of mucus secreted while at the same time decreasing the ability of the lungs to clear these secretions. Smoking also causes the small airways in the lungs to be narrowed and more prone to collapse. The results of these effects are an increased susceptibility to infection, chronic cough and increased chance of pulmonary complications. Lastly, smokers also have increased sensitivity to stimuli and increased bronchial reactivity, increasing the chance for bronchospasm and other life threatening pulmonary processes.

This is not just theory. There have been multiple studies confirming that smoking increases the incidence of pulmonary complications after an anesthetic as much as six times. Smoking has been shown to be an independent risk factor for complications ranging from complications of lung function, wound healing, cardiovascular events such as heart attack.

SMOKING CESSATION
It seems that within 12-24 hours of smoking cessation, there is a significant decrease in the effects of carbon monoxide in the body and much of the nicotine that is in the bloodstream will have been eliminated. This should improve oxygen supply and reduce oxygen demand. This is a good thing from the cardiovascular standpoint!

Unfortunately, the picture is not so clear and simple. It seems to take at least 48 hours to begin to show an improvement in the increased bronchial reactivity seen in smokers. It probably takes as much as two weeks for a significant improvement. So, just in terms of pulmonary effects, a short-term cessation of smoking does not seem to make much of a difference. Patients who quit for more than four weeks do seem to a have a decreased risk of complications. In addition, patients who are able to quit for ten weeks or more have their risk reduced to almost the same as patients that have never smoked.

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History

Opium, alcohol etc were used in antiquity.

Bromide first used 1853, and an account of Bromism in Evelyn Waughs "The Ordeal of Gilbert Pinfold". Before 1900, Chloral Hydrate, Paraldehyde, Urethan, and Sulfonal were in use. Barbiturates were first synthesised in 1864 on St. Barbaras Day (which celebrates the day long ago when the father of a 4th century virgin and martyr was struck dead by lightning after unjustifiably beheading same. St. Barbaras is also the Patron Saint of Gunners and Arsenals). Phenobarbital first used in 1912 Thiopentone introduced in World War II - killed many in Pearl Harbour because too much was unknowingly given to patients in hypovolaemic shock. Benzodiazepines first synthesised 1933, Chlordiazepoxide first clinically used in 1960. Propofol is relatively recent - 1993.

Charpentier first synthesised and used Promethazine, the first major tranquiliser, in the 1930's and Chlorpromazine in the 1950's.

Nitrous Oxide was first `abused' by travelling entertainers; then in 1890's successfully used for dental extractions and anaesthesia.

Ether and Chloroform were the first drugs to make inhalational anaesthesia possible. Ether was used first, but Chloroform was easier to administer. Commenced in 1847, Simpson, for obstetrics; use ended in 1900's due to cardiac irritability and hepatic damage (obligate hepatotoxin via phosgene). Ether then regained popularity. They were usually given by open drop onto wire frames, but machines not unlike those in use now were made by Boyle in the 1920's. Halothane, the first potent volatile agent was first use in 1956; Isoflurane in the 1980's.

Spinal anaesthesia became popular as an alternative to ether, but suffered in the late 1930's when several patients became paraplegic. Now spinal and epidural anaesthesia are much more common.

Early anaesthetics were given by assistants to the surgeon, and in the USA it was more common for a non-medical person to do so under the supervision of the surgeon (these are now the CRNA's of today). In England, doctors with a particular interest in anaesthesia became anaesthetists and the specialist practice of anaesthetics is the result.

October 16th 1846 

First successful public demonstration of anaesthesia

Massachusetts General Hospital, Boston

 Anaesthetist: William Thomas Green Morton

Agent: Diethyl Ether

Patient: Gilbert Abbott

Operation: Excision of tumour under jaw

Surgeon: John Collins Warren

Comment: “Gentlemen, this is no humbug”

What is anaesthesia?

General Anaesthesia - reversible unrousable unconsciousness, usually drug induced.

Local anaesthesia - useless vague term referring to the use of local anaesthetics somehow.

Topical anaesthesia - anaesthesia of skin or mucous membranes by topical appliation of local anaesthetics.

Infiltration anaesthesia - anaesthesia of tissues by direct injection of local anaesthetic where it is needed - ie for excision of skin lesions.

Regional anaesthesia (`conduction blocks' or `blocks') - anasthesia of a part of the body by injecting local anaesthetic into the nerves that go there. Simple blocks include finger blocks, ankle blocks, etc; more complex blocks include plexus blocks, and `major regionals' mean epidural or spinal anaesthesia.

Conscious Sedation - sedation and anxiolysis with consciousness retained.

Neurolept Analgesia - analgesia, disinterest and psychomotor retardation; often little anxiolysis.

What do Anaesthetists do?

Patients are usually seen by the anaesthetist preoperatively. We have a chat and decide what we think is the best way to provide anaesthesia for surgery and what techniques and drugs will be used. A discussion of the risks and benefits of the various approaches should result in an agreed plan. This is very important as the safety of an anaesthetic depends a lot on individualisation and selecting the appropriate technique. Exactly what will happen should be explained to the patient. Both common risks (pain, nausea, sore throat, muscle pain after sux, etc etc) and rare but serious risks (death, paraplegia, etc) should be explained and the patients consent obtained. Usually it is not signed separately.

Responsibility for anaesthesia rests with the anaesthetist, not the surgeon.

The anaesthetist stays with the patient from the time we send them off to sleep until care is passed on to recovery staff, however our responsibility legally relates to the entire period from the time the premed is given until full recovery from the anaesthetic.

Once the patient is asleep, we continuously monitor the adequacy of breathing, arterial oxygen saturation and pulse, heart beat, CO2 and ariway pressures while ventilated, etc; more specialised monitoring is used in special circumstances, ie brain monitoring in neurosurgery. The patient is carefully positioned so as to not cause nerve or skin damage. We try to give the right doses of the right drugs and hope the patient is unconscious.

Fortunately if the patient is able to hear something (or even feel something) they usually can't remember it. There is no way that we can be sure that a given patient is asleep, particularly once they are paralysed and cannot move; in a way the art of anaesthesia is a sophisticated form of guesswork. It reallys is art more than science; the latter seems more obvious when one first gets a look at the `technical' nature of our practice, but if you ever watch new people doing it you realise that experience is far more important than knowledge alone.

At the end of the operation we wake the patient up, extubate them or remove the laryngeal mask or whatever and transport the patient to recovery, or ICU. Usually we then wait awhile to make sure the patient is OK. We are responsible for ensuring that adequate analgesia is ordered. Usually the anaesthetist tries to visit the patient post-op.

Anaesthetists run most acute pain services and often have substantial input to ICU and the ER.

Anaesthesia alone in healthy well patients has a mortality (due to unexpected drug reactions, haste, device malfunction, etc) of 1:500,000. This contrasts with the 1:30 chance of being killed or maimed if you are a driver from the age of 17 to 25, and is far less than the risk of surgery. Overall the risk of death due to anaesthesia in all patients undergoing surgery is about 1:30,000. This is about the same risk of death and/or disablility as driving 10km to and from work in busy traffic for a few months.

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ANAESTHESIA IS A TIGHT ROPE WALKING

What a job!

WE'VE GOT TO MAINTAIN A BALANCE WITH ALL THE FORCES OF NATURE,THAT'S WHAT ANAESTHESIOLOGISTS ARE MEANT FOR.

Favorites

Here's a list of some of my favorite movies:

Jules and Jim, Manhattan, Breaking the Waves

Here's a list of some of my favorite music:

Nirvana, Frank Sinatra, Ibrahim Ferrer