PSWT questions Flashcards
Define pulsed short wave
PSWT involves a device that delivers an electric and magnetic field in short pulses with a time gap in between
What are the 2 fields produced by PSW machines?
Electric - comparable to the condenser field in a traditional SWT machine
Magnetic - comparable to inductothermy
What does Pulse repetition rate (PRR) mean?
Number of pulses delivered per second
What does Pulse Duration (PD) mean?
Duration of each ‘ON’ phase. Very short, measured in microseconds.
Peak and mean power
Power delivered from the machine. Combination of PRR and PD allows mean power to be controlled.
What is the Mean Power table
Identifies all the potential combinations of PRR and PD, and allows the machine to be ‘set’ to deliver a specific mean power. The tables are not interchangeable between models and it is important that the correct table is used for the machine available or else an incorrect clinical dose could be applied
When is heating of the tissues detectable?
It has been shown through reasearch that heating effect can be measured with power levels over 5 watts, though on average it becomes more apparent at 11 watts mean power. Important to remember that is heating of tissues would be contraindicated to stay below the power on that machine believed to deliver heating.
Where is PSW best absorbed within tissues
The PSW will be transmitted through tissues, and will be absorbed in those of low impedance e.g. muscle, nerve, those that are highly vascular, tissues where there is oedema, effusion or recent haemotoma
effect of PSWT on tissues which are inflammed
Cells which are involved in the inflammatory process present a reduced cell membrane potential which disrupts their function. The application of PSWT is claimed to restore the cell membrane potential to their ‘normal’ values. This is said to be done by direct ion transport or activation of pumps e.g. sodium potassium pump. Evidence supports the contention that the energy absorbed in the membrane and that via a mechanism of signal transduction, stimulates or enhances intracellular effects.
Therapeutic effects of PSWT
Reduces pain from injury due to the inhibition of sensory impulse transmission, leading to a sedative effect in the tissues.
Inflammatory pain is reduced due to vasodialation and absorption of the exudates (leakage from cells)
Muscle spasm pain reduces due to vasodialiation and removal of excess lactic acid and other products which produce muscle soreness
It increases the speed of recovery process of soft tissue injuries by increasing the activity of fibroblasts and the stimulation of ATP and protein synthesis.
Can increase tendon extensibility and improve muscle performance as it can lead to the elongation of collagenous structures
Aids the resolution of haemotomas by increasing the rate of interstitial fluid drainage and increasing venous return
What are the common treatment guidelines for acute conditions:
mean power - less than 3 Watts ( the more acute the presentation then the lower the delivery of mean power)
Use narrower pulses and a higher repetition rate is shown to be beneficial
Time - 10 mins should be sufficient
What are the common treatment guidelines for sub-acute conditions:
Mean power - 2-5 Watts
As the condition becomes less acute , use wider pulses
Time - 10-15mins
What are the common treatment guidelines for chronic conditions:
Mean power - more than 5 watts (but if you do not want heating then ensure it is kept lower than 12 watts)
Pulses of longer duration are of benefit
Time - 15-20 minutes
