Principles of the anaesthetic machine

Background: The non-availability of the sophisticated anaesthetic machine and the necessary equipment to administer inhalant anaesthetic in the field hospitals make their use practically unfeasible for the field veterinarians. Therefore, the present study was undertaken to evaluate the effect of propofol, ketamine and their combination ‘Ketofol’ as a TIVA on certain haematological, serum biochemical and hormonal profiles in atropine and xylazine premedicated dogs. Methods: The study was conducted in eighteen clinical cases of dogs of either sex. The animals were randomly divided into three groups with six animals in each group. All the three groups were premedicated with Atropine sulphate @ 0.04mg/kg body weight and xylazine HCl @ 0.5mg/kg body weight intramuscularly. In group-I, propofol @ 5mg/kg body weight, in group-II, ketamine @ 5mg/kg body weight and in group-III, ketofol @ 4mg/kg body weight was administered intravenously for induction after 15 minutes of pre-anesthetic administration. Surgical anaesthesia was maintained for 90 minutes in all three groups viz. group-I, group-II and group-III with propofol @ 2.5mg/kg. b.w., ketamine @ 2.5mg/kg b.wt. and ketofol @ 2mg/kg b.wt. respectively by intermittent bolus injection (IBI) technique. Haematological, serum biochemical and hormonal profile were evaluated before administration of the anaesthetic agent (0 minutes) then at 15, 30, 60 and 90 minutes during and after administration of anaesthetic agents. Result: The study revealed that Hb, PCV and TEC were significantly decreased in all the groups at 60 mints and 30 mints respectively. The biochemical evaluation revealed that blood glucose level was significantly increased in all the groups until the end of the experiment. BUN and creatinine value was a significant increase in group-I and group-II than group-III at different time intervals up to the end of the experiment. In all the groups’ alanine aminotransferase (ALT) values significantly increased up to 60th minutes during TIVA whereas AST value was significantly increased in group-II at 30th and 60th minute of the experiment in compare to group-I and group-III. A higher level of cortisol values was recorded in group-I animals for the entire period of observation. There were no changes observed in the case of T3. Transient variables of haemato-biochemical have been reported following propofol, ketamine and their combination (ketofol) as total intravenous anaesthesia (TIVA). Thus, it has been concluded that diligent monitorization and electrolyte support are essential during the period of anaesthesia.

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The Anaesthetic Machine

How to Survive in Anaesthesia ◽

10.1002/9780470757956.ch7 ◽

2008 ◽

pp. 28-35

Keyword(s):

Anaesthetic Machine

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The anaesthetic machine.

Veterinary clinical skills manual ◽

10.1079/9781786391629.0095 ◽

2018 ◽

pp. 95-104

Author(s):

F. Brown ◽

C. Seymour

Keyword(s):

Anaesthetic Machine

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Gas Supply and the Anaesthetic Machine

The Physics, Clinical Measurement and Equipment of Anaesthetic Practice for the FRCA ◽

10.1093/oso/9780199595150.003.0026 ◽

2011 ◽

Author(s):

Patrick Magee ◽

Mark Tooley

Keyword(s):

Critical Temperature ◽

Anaesthetic Machine ◽

Liquid Oxygen ◽

Liquid Form ◽

Relief Valve ◽

Gaseous Oxygen ◽

Hospital Building ◽

Pass Through ◽

Delivery Pipe ◽

Gas Supply

In Europe and other advanced medical communities, medical gases are generally supplied by pipeline, with cylinders available as back up. Large hospitals usually have oxygen supplied and stored in liquid form, since one volume of it provides 840 volumes of gaseous oxygen at 15◦C. It is stored in a secure Vacuum Insulated Evaporator (VIE) on the hospital site. The arrangement is shown in Figure 22.1. The VIE consists of an insulated container, the inner layer of which is made of stainless steel, the outer of which is made of carbon steel. The liquid oxygen is stored in the inner container at about−160◦C (lower than the critical temperature of−118◦C) at a pressure of between 700 and 1200 kPa. There is a vapour withdrawal line at the top of the VIE, from which oxygen vapour can go via a restrictor to a superheater, where the gas is heated towards ambient temperature. Where demand exceeds supply from this route, there is also a liquid withdrawal line from the bottom of the VIE, from which liquid oxygen can be withdrawn; the liquid can be made to join the vapour line downstream of the restrictor and pass either through the superheater or back to the top of the VIE. The liquid can also be made to pass through an evaporator before joining the vapour line. After passing through the superheater, the oxygen vapour is passed through a series of pressure regulators to drop the pressure down to the distribution pipeline pressure of 410 kPa. It should be remembered that no insulation is perfect and there is a pressure relief valve on top of the VIE in case lack of demand and gradual temperature rise results in a pressure build up in the container. There is a filling port and there is usually considerable wastage in filling the VIE; the delivery hose needs to be cooled to below the critical temperature, using the tanker liquid oxygen itself to cool the delivery pipe. The whole VIE device is mounted on a hinged weighing scale and is situated outside the hospital building, protected by a caged enclosure, which also houses two banks of reserve cylinders.

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The anaesthetic machine

Anaesthesia & intensive care medicine ◽

10.1016/j.mpaic.2018.12.003 ◽

2019 ◽

Vol 20 (2) ◽

pp. 67-71 ◽

Cited By ~ 1

Author(s):

Nicholas Record ◽

Christina Beecroft

Keyword(s):

Anaesthetic Machine

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Response Times to Visual and Auditory Alarms during Anaesthesia

Anaesthesia and Intensive Care ◽

10.1177/0310057x9602400609 ◽

1996 ◽

Vol 24 (6) ◽

pp. 682-684 ◽

Cited By ~ 34

Author(s):

R. W. Morris ◽

S. R. Montano

Keyword(s):

Response Times ◽

Red Light ◽

Anaesthetic Machine ◽

Heart Beat ◽

Visual Signal ◽

False Alarms ◽

Laptop Computer ◽

Audible Alarm ◽

High Level ◽

Time Critical

Objective To measure and compare the response times to audibly or visually presented alarms in the operating theatre. Methods The time taken by anaesthetists to cancel randomly generated visual and audible false alarms was measured during maintenance of routine anaesthesia. Alarms were generated and times recorded by a laptop computer on the anaesthetic machine. The visual signal was a 15mm diameter red light positioned next to the physiological monitor mounted on top of the machine. The audible alarm was a Sonalert® buzzer of the type incorporated into many medical devices. Results Nineteen anaesthetists provided a total of seventy-two hours of data (887 alarm events). The response times to visual alarms was significantly longer than to audible alarms (P=0.001 Mann Whitney U test). Conclusions The ability of anaesthetists to appreciate changes in patient physiology may be limited by delays in noticing information presented by monitors. The rapid response to the vast majority of alarms indicates a high level of vigilance among the anaesthetists studied. However, this study suggests that it is safer to rely on audible rather than visual alarms when time-critical information such as oxygenation, heart beat and ventilator disconnection is concerned. Visual alarms would appear to be more appropriate for conveying less urgent information.

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