PSI is short for Pounds per Square Inch which is a unit measure of pressure. We have talked to hundreds of nurses, doctors, tech, medics etc about the SplashCap and the question frequently comes up: “What’s the PSI?”
The simple answer is:
- An impact pressure of 8 can be generated when using the SplashCap.
- The SplashCap generates pressures within the recommended ranges for syringe irrigation.
- The SplashCap generates at least as much pressure as commonly used irrigation bottles with holes punched in the lids.
- Using two hands will allow you to squeeze harder and generate more pressure
- Some wounds such as those around the eye require minimal pressure.
An even more detailed answer is that the PSI generated by the SplashCap or any other irrigation device depends on a number of factors, including the following:
Where in the system is the pressure measured.
How is the pressure measured.
How is the pressure being generated.
What kind of device was used.
How large of a diameter was used for a nozzle.
How much manual pressure is applied.
There are different studies since the mid-70’s that showed that pressurized irrigation improved wound cleansing and that low pressure irrigation with asepto bulb syringes was less effective.
For those interested in the topic of wound irrigation, a more detailed review of the literature will be posted here in the future. What you will find is that there is no standard method of measuring “psi” between investigators, there is no standard description of how irrigation streams were generated, and there have been widely varying results reported.
Our approach has been to measure the horizontal distance, X, traveled by the irrigation stream generated at a particular height, Y, and relate that to physics equations describing fluid trajectories. An irrigation stream with a higher PSI, P, at the nozzle will travel a farther distance than an irrigation stream with a lower PSI at the nozzle. If you know the height of the stream off the ground, and you measure the distance the stream travels, you can determine the velocity, V, that the stream had coming out of the container.
Knowing the velocity, you can relate that to the pressure exerted by a stream of water on an object at the nozzle opening. So by measuring the distance of an irrigation stream, you can determine what the velocity was coming out of the nozzle; and therefore, what the pressure would have been had that same stream with the same force been applied to irrigate a wound in front of the nozzle.
Unlike prior studies, these results are easily confirmed and validated since there is no special laboratory equipment needed. All you need is a yardstick (a mop!) and your irrigation device, whether it is an irrigation bottle with the SplashCap attached, a syringe, a syringe with a shield attached, etc. You can determine yourself how much pressure you apply using a your own typical technique.