7: infusion pump, defib, dialysis

Question 1

Infusion pumps

Answer 1

•	Medical device enabling controlled deliverance of fluids to patients
•	Administrative routes-
o	IV
o	Subcutaneous
o	Arterial
o	Epidural
•	Components-
o	Fluid reservoir
o	Flow restriction/control
o	Fluid line
o	Patient connection
o	Catheter/access

Question 2

Types of infusion pumps

Answer 2

•	Gravity-
o	Simplest/cheapest form
o	Pressure determined by height above patient
o	Counting drips per minute = flow rate
•	Syringe driver-
o	Fluid held in syringe with moveable piston providing flow rate
o	Low volume/low rate
o	Electronics control speed, distance and force
•	Volumetric
o	Peristaltic pumping action
•	Elastomeric
o	In home patients
o	No external power source required
o	Flow regulated by elastic stretch of bladder
o	No alarms or safety features
o	Less accurate

Question 3

Defibrillation

Answer 3

• Arrhythmias corrected by applying electric shock to heart
• Not used to treat flat lining patients!!
• DC pulse better- applies a shorter, higher amplitude
• Latest bi-phasic defibs use less current during each phase and less tissue damage
• Cardioverters ensure pulse is delivered after R-wave, well before T-wave

Question 4

Sections of dialysis machine

Answer 4

• Purified water: utilised to be mixed with and subsequently dilute the dialysate concentrate
• Dialysate concentrate: a solution of electrolytes and glucose, mixed with water to create a substance with a suitable concentration gradient
• Metering pumps: 2 utilised to move precise amounts of respective purified water or dialysate concentrate into the mixing chamber
• Mixing chamber: mixes the water with the dialysate concentrate to form dialysate of suitable concentration
• Pumps: 2 used to enable the respective flow of the dialysate or arterial blood through the exchange chamber
• Exchange chamber: where the dialysate removes waste from the blood via diffusion across the chambers membrane
• Chamber membrane: enables diffusion and subsequent filtration between the dialysate and the arterial blood
• Waste is removed from the system, and the filtered arterial blood is returned to the patient as venous blood