It was January 1845. Boston Massachusetts General Hospital’s Surgical Theatre was never so empty as then. A monotonous and boring speech about cranial trepanation did not attract a broad auditorium. Meeting of a thick and inelegant drill, in connection with human bone and brain meninges, almost always resulted in an exacerbated infection and a terrible death of the patient.
Among fleers and whispers of the students, it could be heard:
“Humbug, seriously? How He wants to do it, it’s impossible.”
Soon after this presentation, Horace Wells was trying to do the first painless operation. After the lecture, Dr Warren called the man with a dense reddish hair:
“So, there is a man, who claims, that he invented something to relieve pain during operation… So, if someone is interested you could listen a bit about it… “
Maybe it seems to be different, but the surgical blade and pain were inseparably connected; anyone, who thought that operation without suffering is possible, was sentenced to ostracism. The dentist from Harford tried to change this axiom.
A volunteer with red, obese face took a seat and started inhaling a gas from a rubber bag. His head dropped and eyes closed. Wells grasped the tongs and begun pulling out the tooth. The man screamed terribly, and accompanying to him, a group of people in the benches, started laughing.
The ashamed doctor suddenly packed all his devices to the bag and left the room in hurry. After a couple of years, Horace Wells committed a suicide in a jail, as experimenting with chloroform conducted him to madness.
Anaesthesia was brought forth in sorrow.
Nowadays, after decades of attempts, a successful insensibilisation during the surgical procedures is a gold standard of each hospital practice.
However, the General anaesthesia is, really, a combined process.
It may be defined as a reversible and periodic lack of consciousness, accompanied with a muscular relaxation (relaxatio musculorum), the absence of memory (amnesia), cessation of reflexes (areflexia), and, obviously, pain desensitisation (analgesia). All of these components are important for appropriate conductance of the operation.
So how do we can receive all of these in one moment, during hours of surgical manipulation? It needs a mixture of drugs.
Where it begins
During preparation time in the surgical room, the patient meets an anaesthetist, after long and exhausting interview, including, inter alia, drug allergies and previous operations, the time has come to start with the procedure, and the patient is informed about the sequence of circumstances he will be admitted with. It’s not the first visit of the patient in the hospital. They will have been seen by a nursing assistant, nurse or an anaesthetist in the pre-operative clinic weeks ago. This is to make sure that the patient is well prepared for the surgery and that any potential risks of complications or longer stay in the hospital are identified and addressed before knife hits the skin.
It’s not the first visit of the patient in the hospital. They will have been seen by a nursing assistant, nurse or an anaesthetist in the pre-operative clinic weeks ago. This is to make sure that the patient is well prepared for the surgery and that any potential risks of complications or longer stay in the hospital are identified and addressed before knife hits the skin.
Let’s start with monitoring of life functions. At first, a nurse supplies the patient with ECG electrodes, pulse oximeter and BP cuff: the doctor will need it all the time during anaesthesia. These devices are known from generating “peeks” and green waves on the monitor.
A carefully planned choreography of tasks is put in place: last checks and questions – the patient will state what the procedure is, what it involves and where it will take place (especially which side!).
Patient data and notes are carefully checked the last time and consent is finally reaffirmed.
A wary eye of the anaesthetist scans the data, looks over the patient, makes hundreds of micro assessments per minute. Any blood loss, difficulty in accessing the airway, any obstacle, however minor, must be meticulously planned so that the adequate equipment is in the theatre and contingency plans are in place.
From the complicated system of tubes, oxygen begins to escape, directly to the mask put on patient’s face.
First drugs are being administered, and we start with opioids. These well-known and recognised group of medicines is responsible for the relief of pain. Due to the action on opioid receptors in our spine, they provide safety during intubation- a procedure needed to keep the airways clear.
Then we need to relax muscles. Drugs do not differ a lot from substances used by Amazonian Indians in hunting. Curara – the first relaxant, successfully used to the second half of the XXth century, was isolated from Indian arrow venoms.
The patient is suspended between life and death.
General anaesthetic drugs are now given. We could distinguish gas substances, like sevoflurane, desflurane. And liquid injections, like ketamine, propofol or etomidate. All these difficult pharmaceutical names determine compounds used to switch off our consciousness, so: welcome on a board and have a nice journey!
After this cocktail of drugs, the patient is connected to the respirator, which gives breathes, by puffing air into lungs via intubation tube. The alert eye of doctor watches if additional dosages of oxygen are needed, monitors the blood pressure and the heart rate.
“Well, it’s time to start!” the anaesthetist announces, just like a conductor after the overture silences the instruments to being a new act.
“Przemyslaw, consultant anaesthetist, “
he starts to mark the first step of theatre introduction. To enhance safety and make sure everyone can speak up if they spot any discrepancy, the hierarchy in the theatre must be flat. Everyone introduces themselves by their first name, leaving their titles and honours behind the double door of the theatre.
The circle begins with every member of the staff: scrub nurses, ODPs, consultants, trainee surgeons, nursing students, and radiographers – they all must unanimously agree at all times; any doubt will cause the whole trance to stop immediately to reassess the situation and address the problem.
“Patient Alpha Foxtrot, admitted for elective procedure; consent form 1 signed.”
Says the surgeon, whilst other members of the team check monitors, forms and grades, including clotting and infection prophylaxis. Finally, every group of staff in the theatre must consent that they’re happy for the surgeon to proceed. Now, the attention centres back at the pilot, the surgeon will hold his scalpel, looking in the eyes of the anaesthetist to nod for this crucial, last question.
OK to cut?
After the operation, when drug concentration in blood systematically drops, the patient wakes up. It’s after the procedure: now we need to maintain the analgesic action to heal the postoperative pain. All blades, swabs, instruments and sutures are carefully counted and noted down to ensure that everything is accounted for and nothing was accidentally misplaced or left in the wound of the patient.
How does it work?
Our consciousness is working due to cerebral cortex activity. If we cut off the power station supplying this structure of Central Nervous System, we generate sleep.
Sleep is one of main life functions. It is suspected that specific part of the brain, called reticular system includes the centre of reinforcement for our consciousness, probably inhibition of reticular ascending system is the main mechanism of falling asleep. This group of brain cells is thought to be the site of action for general anaesthetics.
The oldest known theory, created in the second half of XIXth century, describes the mechanism of action for these drugs and is still known as the Meyer- Overtone theory. According to this explanation, lipid solubility of the anaesthetic gases cause the uptake of compounds of a drug into neural membranes, which results in a decreased velocity of transmission and, in consequence, the depression of many brain areas.
Modern used medicines act also by affecting a plethora of other mechanisms, including GABA receptors, or NMDA receptors.
Should we be afraid of anaesthesia?
As we mentioned, the status of unconsciousness and lack of memory is reversible. After the operation, our memory and cognitive functions return to the previous, preoperational stage.
A little hangover seems to be the most common syndrome, but we can also observe more severe symptoms, like malignant hyperthermia, or breathing centre depression. Taking into account the fact that these symptoms are undoubtedly very rare, the pros really dominate cons for general anaesthesia. Every doctor before deciding on general anaesthesia (GA) is always obliged to thoroughly examine the patient.
Any contraindication usually results in resigning from this method of treatment and undertaking another one, more safe and adequate.