Anaesthetic Machine
Components of a typical machine
Simple schematic of an anaesthesia machine
A modern machine typically includes the following components:
connections to piped hospital oxygen, medical air, and nitrous oxide. Pipeline pressure from the hospital medical gas system (wall outlet) should be around 400 kPa (60 psi; 4 atmospheres).
reserve gas cylinders of oxygen, air, and nitrous oxide attached via a specific yoke with a Bodok seal. Older machines may have cylinder yokes and flow meters for carbon dioxide and cyclopropane. Many newer machines only have oxygen reserve cylinders. The regulators for the cylinders are set at 300 kPa (45 psi; 3 atmospheres). If the cylinders are left on and the machine is plugged into the wall outlet, gas from the wall supply will be used preferentially, since it is at a higher pressure. In situations where pipeline gases are not available, machines may safely be used from cylinders alone, provided fresh cylinders are available.
a high-flow oxygen flush which provides pure oxygen at 30 litres/minute
pressure gauges, regulators and ‘pop-off’ valves, to protect the machine components and patient from high-pressure gases (referred to as ‘barotrauma’).
flow meters (rotameters) for oxygen, air, and nitrous oxide, which are used by the anaesthesiologist to provide accurate mixtures of medical gases to the patient. Flow meters are typically pneumatic, but increasingly electromagnetic digital flow meters are being used. Read the rest of this entry »
Tags: anaesthesia, anaesthesia machineRelated posts
Nanite Anaesthesia and Electrode Euphoria
The way the brain processes sensorial input to let us experience sight, sound, taste and touch has always amazed me, yet neuroscience has not given me the answers I have been looking for. Neuroscience is descriptive, can analyse patterns, and can even attribute activities in certain parts of the brain with certain action, emotion or thought patters. What neuroscience fails to tell us is how the images, sounds and other sensorial input that enters our brain give us the experience we are aware of.
Rodolpho Llinas describes on oscillatory timing and binding principle, that may indeed be a prerequisite for having the experience of awareness we have, but this does still not explain why a ball is experienced as a spherical object and a dice as a cube.
Here comes my hypothesis of how brain activity is transformed into something which can be observed by the Ghost in the Machine. Neurons are like electricity transporting wires. When electricity is transported through a wire, an electromagnetic field is induced. Electromagnetic waves are broadcasted. Could it be that the neuronal activity patterns create an interference pattern which is congruent or isomorphous to the object observed? So that in fact the cavity between the two hemispheres (In Indian literature and Vedanta called the Brahmarandhra) is a kind of spherical projection screen, on which a 3D image sound, scent, taste and touch show is performed, with as a spectator the Soul, as Ghost in the machine? A kind of Brahma’s holodeck? Read the rest of this entry »
Tags: anaesthesiaRelated posts
Anaesthesia Errors and Why They Occur
We often perceive that the most dangerous stage of surgery is the procedure itself. Many of us who undergo surgery fear the process. More often than not, we do not realize that sometimes the anaesthesia used during the operation is the hazardous stage of the process. It has been observed that anaesthesia errors or mistakes in its administration take place in a lot of our hospital operating rooms, a horrible truth that most of us do not have knowledge of until it takes the life of a friend or a loved one.
On the other hand, the use of anaesthesia is very significant as its introduction in the medical world has made life saving surgeries possible. Today, surgery is next to impossible if surgeons do not use this medical wonder. Further, people prefer anaesthesia to alleviate the pain of undergoing surgery.
Be that as it may, anaesthesia errors or mistakes still happen. But why do anaesthesia errors occur? Let us see the top three reasons why these happen.
First reason is poor communication between staff members in the hospital. This poor communication could be ascribed to personal conflicts, faulty procedures of technicians in dealing with anaesthesia and even fatigue. Oftentimes, errors in documenting the patient’s age and weight, medical history and past reactions to anaesthesia result in anaesthesia error. Read the rest of this entry »
Tags: anaesthesia, type of anaesthesia