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A system for halothane anesthesia in experimental surgery
Physioh~gy and Behavior. Vol. 4, pp. 433--434. Pergamon Press, 1969. Printed in Great Britain
BRIEF COMMUNICATION A System for Halothane Anesthesia in Experimental Surgery' E U G E N E M. T A Y L O R
Department of Psychology, Arizona State University, Tempe, Arizona
(Received21 November 1968) TAYLOR,E. M. A system for halothane anesthesia in experimental surgery. PHYSIOL.BmaAV.4 (3) 433--434, 1969.--An easily assembled, inexpensive and self-contained anesthesia apparatus is described for the administration of Halothane vapor with maximal control of inspired gas concentration. Anesthesia
Halothane
Experimentalsurgery
RECOGNIZINGthe pharmacological and practical advantages of halothane as an ~ t h e t i ¢ agent but the limitations of available apparatus for its administration, Luschei and Mehaffey [1] have developed an oxygen-halothane vaporizer which makes the use of this gas practical for experimental surgery. The apparatus reported here is a modification of the Luschei device with what we believe to be a number of fundamental advantages, particularly with regard to expense and portability. The machine is distinct from Luschei's in using a self contained air source instead of oxygen to vaporize the halothane. This obviates heavy oxygen tanks and expensive regulators. The air source is an inexpensive and widely available aquarium air pump, ("Silent Giant" made by the Aquarium Pump Supply Co., Prescott, Arizona, available from biological supply houses). This pump uses an oscillating armature-driven diaphragm to provide air flow at up to 3 liters per rain. Maximum air pressure is 250 mm Hg against a closed system. The air is oil-free and delivery is essentially non-puisatlle. Air from the pump is divided by a pair of metering valves, (#65720, Van Waters-Rogers Co.), and directed through calibrated flow meters, (RGI compact shielded type, one each of size 10 and size 12, Cole-Parmer Co.), and a gas diffusing device to provide controlled mixtures of halothane vapor and air. (Fig. 1). The mixture is delivered to the animal with a tracheal cannula with a side-arm for the expired gas to exit or to a face mask with an expiratory valve. It has been our experience that flow rates of 20-30 mi/min of halothane-saturated air mixed with 1200-1600 ml/min of pure air have been s u t ~ e n t for induction of anesthes/a in primates, (baboons), of body weight 8-12 kg, the animals having been premedicated with phencyclidine hydrochloride, (Sernylan, Parke-Davis), 1 mg/kg. The premedication with
A\ B\
/D
/
E
FIG. 1. Diagram of the Circuit. The pump (A) supplies air to two metering valves (G) and (F). Valve (G) controls the flow of air, through a floating-ball flow meter (B), which is calibrated 0-80 ml/min (RGI No. 10), to a coarse porosity glass diffusion tube (C) which is immersed in liquid halothane contained in a side-arm test tube. Valve fir) controls the flow of pure air through a flow meter (E) which is calibrated 0-2000 ml/min (RGI No. 12). Pure air and halothane saturated air emergi'n~ from the side arm of the test tube are mixed in "T" connector (D) from which they are delivered to the animal.
1Supported by National Heart Institute grant No. 5 R01 HE 10574. 433
434
TAYLOR
Sernylan was done, in part, to potentiate the anesthetic but principally to allow cannulation of the trachea in these animals. We have used the machine at similar concentrations to anesthetize a variety of other laboratory animals, (cats, rats and new-born kittens), without premedication and with no modification of the apparatus except adjustment of total flow rates. We have used the machine for about a year for several procedures per week without maintenance or repairs
of any kind. Once set, flow rates do not drift measurably during proc~ums lasting as long as 9 hr. Tim apparatus is ~ l y portable as it weighs less than 2 kg. Overall dimensions am approximately 20 × 15 × 35 cm (Fig. 2). Total cost of the apparatus is $70.00 including the air pump. This could be further reduced by the use of less accurate valves, a smaller capacity pump etc. depending on particular requirements of the user.
~ C E 1. Luschei, E. S. and J. J. Mehaffey, Small animal anesthesia with halothane, J. appl. Physiol. 22: 595-597, 1967.
FIG. 2. Photograph of the Apparatus. The flow meter and valve assembly has been attached to the plastic housing of the air pump with an interlocking pair of spring steel "battery clips", one of which is cemented to the pump housing with epoxy cement. A neoprene stopper and vinyl tubing has been employed, as natural rubber is gradually attacked by halothane vapors.
(Jacing page 434)
BRIEF COMMUNICATION A System for Halothane Anesthesia in Experimental Surgery' E U G E N E M. T A Y L O R
Department of Psychology, Arizona State University, Tempe, Arizona
(Received21 November 1968) TAYLOR,E. M. A system for halothane anesthesia in experimental surgery. PHYSIOL.BmaAV.4 (3) 433--434, 1969.--An easily assembled, inexpensive and self-contained anesthesia apparatus is described for the administration of Halothane vapor with maximal control of inspired gas concentration. Anesthesia
Halothane
Experimentalsurgery
RECOGNIZINGthe pharmacological and practical advantages of halothane as an ~ t h e t i ¢ agent but the limitations of available apparatus for its administration, Luschei and Mehaffey [1] have developed an oxygen-halothane vaporizer which makes the use of this gas practical for experimental surgery. The apparatus reported here is a modification of the Luschei device with what we believe to be a number of fundamental advantages, particularly with regard to expense and portability. The machine is distinct from Luschei's in using a self contained air source instead of oxygen to vaporize the halothane. This obviates heavy oxygen tanks and expensive regulators. The air source is an inexpensive and widely available aquarium air pump, ("Silent Giant" made by the Aquarium Pump Supply Co., Prescott, Arizona, available from biological supply houses). This pump uses an oscillating armature-driven diaphragm to provide air flow at up to 3 liters per rain. Maximum air pressure is 250 mm Hg against a closed system. The air is oil-free and delivery is essentially non-puisatlle. Air from the pump is divided by a pair of metering valves, (#65720, Van Waters-Rogers Co.), and directed through calibrated flow meters, (RGI compact shielded type, one each of size 10 and size 12, Cole-Parmer Co.), and a gas diffusing device to provide controlled mixtures of halothane vapor and air. (Fig. 1). The mixture is delivered to the animal with a tracheal cannula with a side-arm for the expired gas to exit or to a face mask with an expiratory valve. It has been our experience that flow rates of 20-30 mi/min of halothane-saturated air mixed with 1200-1600 ml/min of pure air have been s u t ~ e n t for induction of anesthes/a in primates, (baboons), of body weight 8-12 kg, the animals having been premedicated with phencyclidine hydrochloride, (Sernylan, Parke-Davis), 1 mg/kg. The premedication with
A\ B\
/D
/
E
FIG. 1. Diagram of the Circuit. The pump (A) supplies air to two metering valves (G) and (F). Valve (G) controls the flow of air, through a floating-ball flow meter (B), which is calibrated 0-80 ml/min (RGI No. 10), to a coarse porosity glass diffusion tube (C) which is immersed in liquid halothane contained in a side-arm test tube. Valve fir) controls the flow of pure air through a flow meter (E) which is calibrated 0-2000 ml/min (RGI No. 12). Pure air and halothane saturated air emergi'n~ from the side arm of the test tube are mixed in "T" connector (D) from which they are delivered to the animal.
1Supported by National Heart Institute grant No. 5 R01 HE 10574. 433
434
TAYLOR
Sernylan was done, in part, to potentiate the anesthetic but principally to allow cannulation of the trachea in these animals. We have used the machine at similar concentrations to anesthetize a variety of other laboratory animals, (cats, rats and new-born kittens), without premedication and with no modification of the apparatus except adjustment of total flow rates. We have used the machine for about a year for several procedures per week without maintenance or repairs
of any kind. Once set, flow rates do not drift measurably during proc~ums lasting as long as 9 hr. Tim apparatus is ~ l y portable as it weighs less than 2 kg. Overall dimensions am approximately 20 × 15 × 35 cm (Fig. 2). Total cost of the apparatus is $70.00 including the air pump. This could be further reduced by the use of less accurate valves, a smaller capacity pump etc. depending on particular requirements of the user.
~ C E 1. Luschei, E. S. and J. J. Mehaffey, Small animal anesthesia with halothane, J. appl. Physiol. 22: 595-597, 1967.
FIG. 2. Photograph of the Apparatus. The flow meter and valve assembly has been attached to the plastic housing of the air pump with an interlocking pair of spring steel "battery clips", one of which is cemented to the pump housing with epoxy cement. A neoprene stopper and vinyl tubing has been employed, as natural rubber is gradually attacked by halothane vapors.
(Jacing page 434)