Method of testing a surgical system
View Patent ↗A method of testing a surgical system that takes advantage of the fact that in a balanced irrigation/aspiration system (inflow≧outflow) the duration of the aspiration pressure recovery to the irrigation fluid source pressure immediately following pump stop is independent of pump run time. This method provides a more reliable way of detecting restricted irrigation flow configurations not detectable by the current methods, such as marginal irrigation flow cases that could potentially lead to surgical complications (e.g. chamber collapse during post-occlusion break surge).
1. A method for testing a surgical irrigation/aspiration system having an aspiration pump, comprising:
determining a first system pressure recovery time after discontinuing aspiration of a fluid for a first time interval from a test chamber, wherein the first system pressure recovery time is a time detected for a system pressure to return to a predetermined pressure;
determining a second system pressure recovery time after discontinuing aspiration of fluid for a second time interval from the test chamber;
determining a dependence of the recovery time on a length of aspiration based on a comparison of the first system pressure recovery time with the second system pressure recovery time, wherein determining the dependence comprises determining if the second system pressure recovery time is greater or less than the first system pressure recovery time; and
determining a state of the irrigation/aspiration system fluidic balance based on the determined dependency of the recovery time.
2. The method of claim 1 ,
wherein the fluid is supplied to the test chamber from an irrigation fluid container;
wherein the system pressure comprises a pressure in a fluid path between the irrigation fluid container and the aspiration pump; and
wherein the system pressure used to determine a first or second system pressure recovery time is detected using a pressure sensor coupled to the fluid path.
3. The method of claim 1 , further comprising:
comparing the first system pressure recovery time to a first threshold, wherein if the first system pressure recovery time is greater than the first threshold, the state of the irrigation/aspiration system fluidic balance is determined to be unacceptably restricted.
4. The method of claim 1 :
wherein the state of the irrigation/aspiration system fluidic balance corresponds to at least one of two states including:
a) a balanced irrigation/aspiration system in which a duration of the aspiration pressure recovery to an irrigation fluid source pressure following aspiration pump stop is substantially independent of pump run time; or
b) a restricted irrigation flow configuration.
5. The method of claim 4 , wherein, if the second time interval of aspiration is greater than the first time interval of aspiration, state a) is indicated by the second system pressure recovery time being less than or equal to the first system pressure recovery time.
6. The method of claim 4 , wherein, if the second time interval of aspiration is greater than the first time interval of aspiration, state b) is indicated by the second system pressure recovery time being greater than the first system pressure recovery time.
7. A method for testing a surgical irrigation/aspiration system having an aspiration pump, comprising:
monitoring a system pressure recovery profile after discontinuing aspiration of a fluid from a test chamber;
determining a presence or absence of a characteristic test chamber refill response in the recovery profile; and
determining a state of an irrigation/aspiration system fluidic balance based on the determined presence or absence of the chamber refill response;
wherein the fluid is supplied to the test chamber from an irrigation fluid container; and
wherein the system pressure comprises a pressure in a fluid path between the irrigation fluid container and the aspiration pump.
8. The method of claim 7 ,
wherein a pressure for the system pressure recovery profile is detected using a pressure sensor coupled to the fluid path; and
wherein a pressure of the irrigation fluid container, as detected through the fluid path by the pressure sensor, is recorded prior to starting aspiration of the fluid.
9. The method of claim 7 , wherein aspiration of the fluid from the test chamber comprises aspirating fluid from the test chamber through the aspiration pump for a predetermined time interval.
10. The method of claim 7 , wherein the state of the irrigation/aspiration system fluidic balance corresponds to at least one of two states including:
a) a balanced irrigation/aspiration system in which a duration of the aspiration pressure recovery to an irrigation fluid source pressure following aspiration pump stop is substantially independent of pump run time; or
b) a restricted irrigation flow configuration;
wherein state b) is indicated by the presence of the characteristic test chamber refill response in the recovery profile and wherein state a) is indicated by the absence of the characteristic test chamber refill response in the recovery profile.
11. The method of claim 10 , wherein in the balanced irrigation/aspiration system state, the pressure recovery profile corresponds to:
pressure
(
time
)
=
Irrigation
source
pressure
-
(
Initial
system
pressure
after
aspiration
pump
stop
+
irrigation
source
pressure
)
*
e
-
time
time
_
const
where time_const is dependent on system configuration.
12. The method of claim 10 , wherein in the restricted irrigation flow configuration, a test chamber refill time, after the aspiration pump discontinues, is substantially proportional to aspiration pump run time.
13. The method of claim 7 , wherein the fluid is aspirated from the test chamber for a first time and wherein the method further comprises:
aspirating the fluid from the test chamber for a second time;
monitoring the system pressure recovery profile following aspiration of the fluid from the test chamber for the second time; and
determining a presence or absence of a characteristic test chamber refill response in the system pressure recovery profile following the aspiration of the fluid from the test chamber for the second time.
14. The method of claim 13 ,
wherein the system pressure recovery profile includes at least one system pressure detected at a known time period after the aspiration of the fluid from the test chamber for the second time;
wherein determining the absence of the characteristic test chamber refill response in the recovery profile comprises determining that the system pressure detected at the known time period is approximately an expected system pressure or at least a predetermined percentage of the expected system pressure; and
wherein determining the presence of the characteristic test chamber refill response in the recovery profile comprises determining that a system pressure detected at the known time period is not at least a predetermined percentage of an expected system pressure.
15. The method of claim 13 , further comprising:
determining a time (t 01 ) for the system pressure to return to a pressure (P 1 ) after aspirating the fluid from the test chamber for the first time; and
determining a time (t 02 ) for the system pressure to return to P 1 after aspirating the fluid from the test chamber for the second time;
wherein determining the absence of the characteristic test chamber refill response in the recovery profile comprises determining that t 02 is less than or equal to t 01 .
16. A method for testing a surgical irrigation/aspiration system having an aspiration pump, comprising:
monitoring a system pressure recovery profile after discontinuing aspiration of a fluid from a test chamber;
determining a presence or absence of a characteristic test chamber refill response in the recovery profile; and
determining a state of an irrigation/aspiration system fluidic balance based on the determined presence or absence of the chamber refill response;
wherein the system pressure recovery profile includes at least one system pressure detected at a known time period after the aspiration of the fluid from the test chamber.
17. The method of claim 16 , wherein determining the absence of the characteristic test chamber refill response in the recovery profile comprises determining that a system pressure detected at the known time period is approximately an expected system pressure or at least a predetermined percentage of the expected system pressure.
18. The method of claim 16 , wherein determining the presence of the characteristic test chamber refill response in the recovery profile comprises determining that a system pressure detected at the known time period is not at least a predetermined percentage of an expected system pressure.
19. The method of claim 18 ,
wherein the predetermined percentage is approximately 50%;
wherein the expected system pressure is a pressure of the irrigation fluid container; and
wherein the presence of the characteristic test chamber refill response in the recovery profile comprises the system pressure detected at the known time period not being at least approximately 50% of the pressure of the irrigation fluid container.