Modern anaesthesia is safe, despite some of the stories you hear. To compare one hour of being anaesthetised with, say, one hour spent in traffic or a one-hour plane trip, the risk of dying is about one in ten thousand in traffic, about one in one million in an aircraft, and one in 100,000 – 500,000 during the anaesthetic. If you compare one hour of having an anaesthetic with an hour of air travel, then the risk of dying is about five to ten times higher during the anaesthetic. In contrast, an hour spent parachute-jumping carries a risk of death about 20 – 100 times that associated with anaesthesia. The safety of anaesthesia has increased over the years, even though much more complicated operations are being performed, for patients with more severe illnesses. For example, in Australia, the risk of death associated with anaesthesia has decreased to one-tenth of what it was thirty years ago. You can be confident that modern anaesthesia is very safe.

What makes anaesthesia safe ?

A number of factors have contributed to the overall safety of modern anaesthesia. These factors include your anaesthetist, the drugs and equipment used in the Operating Room, and overall medical care. For example, your anaesthetist is responsible for your overall health and safety from the start of your anaesthetic until you leave the recovery room after your operation. Your anaesthetist makes sure that all the anaesthetic equipment is working properly before you undergo anaesthesia. (This is just like the airline pilot who completes a pre-flight check of the aeroplane.) Your anaesthetist knows what to do if a problem occurs with any of the equipment during your anaesthetic. He or she will be with you throughout your operation, watching you and watching your surgeon. Your anaesthetist also continuously watches a number of monitors that measure many of the things happening to you while you are under the effects of the anaesthetic. Should there be any complications, either because of the anaesthetic drugs, or more likely because of the operation, your anaesthetist will respond quickly, having been fully trained in managing emergencies.

There have been major improvements in the drugs used for anaesthesia. Starting in 1846, the first anaesthetics were given with one drug, such as ether or chloroform. Inhaling these drugs was unpleasant, because of the smell and a sensation of choking. induction of anaesthesia was often slow and occasionally patients would struggle and have to be restrained. Because only one drug was used, patients needed heavy doses to make them very deeply anaesthetised. This was to ensure that the patients’ muscles were sufficiently relaxed for the surgeons to be able to operate. After the operation, patients often slept for long periods of time, as they breathed out the large amounts of drug that had been used. Vomiting and severe postoperative pain were very common.

Since the 1940s, anaesthetists have had the benefit of being able to use many new anaesthetic agents. All have contributed to the development of anaesthetic practice as it is today. The newer agents tend to be absorbed less by the body’s fat, which means that they have a shorter duration of action than the older agents. This allows anaesthetists to determine and control the depth of an anaesthetic more precisely for the requirements of each individual patient. However, the principle upon which the use of all of these drugs is based remains common to those of the original agents – ‘sufficient and safe’.

In addition to improvements in anaesthetic agents, there have been major changes in the equipment used to give the anaesthetic and to monitor its effects. As recently as the mid-1970s, anaesthetics were given in modern hospitals in Canada and Australia with only a blood pressure cuff and a stethoscope to monitor the patient. Since then, many new pieces of equipment have been introduced. As a result, anaesthetists are now better able to assess and evaluate what is happening to their patients.