Types of pump
A
Baxter International
Colleague CX infusion
pump
There are two basic classes of pumps. Large volume pumps can pump
nutrient solutions large enough to feed a patient. Small-volume pumps
infuse
hormone
s, such as
insulin
, or other medicines, such as
opiate
s.
Within these classes, some pumps are designed to be portable, others
are designed to be used in a hospital, and there are special systems for
charity and battlefield use.
Large-volume pumps usually use some form of
peristaltic pump
.
Classically, they use computer-controlled rollers compressing a
silicone-rubber tube through which the medicine flows. Another
common form is a set of fingers that press on the tube in sequence.
Small-volume pumps usually use a
computer
-controlled motor turning
a screw that pushes the plunger on a syringe.
The classic medical improvisation for an infusion pump is to place a
blood pressure
cuff around a bag of fluid. The battlefield equivalent is
to place the bag under the patient. The pressure on the bag sets the
infusion pressure. The pressure can actually be read-out at the cuff's
indicator. The problem is that the flow varies dramatically with the
patient's blood pressure (or weight), and the needed pressure varies with the administration route, making this quite
risky for use by an untrained person. Pressures into a vein are usually less than 8 lbf/in² (55
kPa
. Epidural and
subcutaneous pressures are usually less than 18 lbf/in² (125 kPa).
Places that must provide the least-expensive care often use pressurized infusion systems. One common system has a
purpose-designed plastic "pressure bottle" pressurized with a large disposable plastic syringe. A combined flow
restrictor
, air filter and drip chamber helps a nurse set the flow. The parts are reusable, mass-produced
sterile
plastic,
and can be produced by the same machines that make plastic soft-drink bottles and caps. A pressure bottle, restrictor
and chamber requires more nursing attention than electronically-controlled pumps. In the areas where these are used,
nurses are often volunteers, or very inexpensive.
The restrictor and high pressure helps control the flow better than the improvised schemes because the high pressure
through the small restrictor orifice reduces the variation of flow caused by patients' blood pressures.
An air filter is an essential safety device in a pressure infusor, to keep air out of the patients' veins: doctors estimate
that 0.55
cm³
of air per
kilogram
of body weight is enough to kill (200
–
300 cm³ for adults) by filling the patient's
heart
. Small bubbles could cause harm in arteries, but in the veins they pass through the heart and leave in the
patients' lungs. The air filter is just a membrane that passes gas but not fluid or
pathogen
s. When a large air bubble
reaches it, it bleeds off.
Some of the smallest infusion pumps use
osmotic
power. Basically, a bag of salt solution absorbs water through a
membrane, swelling its volume. The bag presses medicine out. The rate is precisely controlled by the salt
concentrations and pump volume. Osmotic pumps are usually recharged with a syringe.
Spring-powered clockwork infusion pumps have been developed, and are sometimes still used in veterinary work
and for ambulatory small-volume pumps. They generally have one spring to power the infusion, and another for the
alarm bell when the infusion completes.
Battlefields often have a need to perfuse large amounts of fluid quickly, with dramatically changing blood pressures
and patient condition. Specialized infusion pumps have been designed for this purpose, although they have not been
deployed.
ชนิดของปั๊มA Baxter นานาชาติ เพื่อนร่วมงาน CX คอนกรีตปั๊มมีสองประเภทพื้นฐานของปั๊ม จำนวนมากสามารถปั้มโซลูชั่นธาตุอาหารพอเพียงให้อาหารผู้ป่วย ปั๊มเล็กปริมาณดอง ฮอร์โมนs เช่น อินซูลินการใช้ ยาอื่น ๆ เช่น ยาเสพติดsภายในคลาสที่เหล่านี้ บางปั๊มถูกออกแบบมาให้พกพา อื่น ๆออกแบบเพื่อใช้ในโรงพยาบาล และมีระบบพิเศษใช้กุศลและสนามรบปั๊มขนาดใหญ่ปริมาณมักจะใช้รูปแบบของ ปั๊ม peristaltic.รายละเอียด ใช้คอมพิวเตอร์ควบคุมลูกกลิ้งบีบอัดเป็นท่อยางซิลิโคนที่ไหลผ่านซึ่งยา อีกแบบฟอร์มทั่วไปคือ ชุดของนิ้วที่กดบนท่อตามลำดับปั๊มเล็กปริมาณมักจะใช้เป็น คอมพิวเตอร์-เปิดมอเตอร์ควบคุมสกรูที่ผลักดันจมูกที่บนเข็มเป็นก่อแพทย์คลาสสิกในการปั๊มคอนกรีตจะทำการความดันโลหิต วางรอบ ๆ ถุงของเหลว เป็นสนามรบที่เทียบเท่าใส่กระเป๋าภายใต้ผู้ป่วย ความดันในถุงชุดแรงดันคอนกรีต ความดันจริงได้ read-out ที่วางของตัวบ่งชี้ ปัญหาคือ ว่า ขั้นตอนที่แตกต่างไปอย่างมากด้วยการผู้ป่วยความดันโลหิต (หรือน้ำหนัก), และความดันต้องแตกต่างกันไปกับกระบวนการดูแล ทำให้มากมีความเสี่ยงเพื่อใช้ให้ผู้ฝึกฝน ความดันในหลอดเลือดดำมักน้อยกว่า 8 lbf/in² (55 kPa. ฉีดบิวพรี และความดันใต้มักน้อยกว่า 18 lbf/in² (125 kPa)Places that must provide the least-expensive care often use pressurized infusion systems. One common system has apurpose-designed plastic "pressure bottle" pressurized with a large disposable plastic syringe. A combined flowrestrictor, air filter and drip chamber helps a nurse set the flow. The parts are reusable, mass-produced sterile plastic,and can be produced by the same machines that make plastic soft-drink bottles and caps. A pressure bottle, restrictorand chamber requires more nursing attention than electronically-controlled pumps. In the areas where these are used,nurses are often volunteers, or very inexpensive.The restrictor and high pressure helps control the flow better than the improvised schemes because the high pressurethrough the small restrictor orifice reduces the variation of flow caused by patients' blood pressures.An air filter is an essential safety device in a pressure infusor, to keep air out of the patients' veins: doctors estimatethat 0.55 cm³ of air per kilogram of body weight is enough to kill (200–300 cm³ for adults) by filling the patient'sheart. Small bubbles could cause harm in arteries, but in the veins they pass through the heart and leave in thepatients' lungs. The air filter is just a membrane that passes gas but not fluid or pathogens. When a large air bubblereaches it, it bleeds off.Some of the smallest infusion pumps use osmotic power. Basically, a bag of salt solution absorbs water through amembrane, swelling its volume. The bag presses medicine out. The rate is precisely controlled by the saltconcentrations and pump volume. Osmotic pumps are usually recharged with a syringe.Spring-powered clockwork infusion pumps have been developed, and are sometimes still used in veterinary workand for ambulatory small-volume pumps. They generally have one spring to power the infusion, and another for thealarm bell when the infusion completes.Battlefields often have a need to perfuse large amounts of fluid quickly, with dramatically changing blood pressuresand patient condition. Specialized infusion pumps have been designed for this purpose, although they have not beendeployed.
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