Burn patient resuscitation system
A system for operating a semi-closed loop and/or a closed loop resuscitation of a burn patient in view of patient information and other physiological data gathered by the system. The system in at least one embodiment includes an urine sensor, an infusion pump and a processor that controls the operation of the infusion pump at least in part from a signal received from the urine sensor.
1. A system for use in resuscitating a patient comprising:
a urine sensor;
an infusion pump;
an electronic medical records interface; and
a processor connected to said urine sensor and said infusion pump, said processor having
means for calculating an infusion rate using an infusion rate model based on at least a current infusion rate received from at least one of said infusion pump and said electronic medical records interface, a current urinary output, and infusion rate model based constants, the new infusion rate is calculated using the following equation
I
t
=
I
t
-
1
+
ⅇ
(
t
)
×
IRC
t
UOC
t
where I t is the new infusion rate, I t-1 is the last infusion rate, e(t) is the urinary output error between the current urinary output and a target urinary output, IRC t is the infusion rate constant at time t based on the hours post burn, and UOC t is the urinary constant, and
wherein the urinary output error is further multiplied by a Gaussian function calculated using a mid-point of a target urinary output range.
2. The system according to claim 1 , wherein the infusion rate constant decreases based on hours post-burn in at least two steps with a first step at 14 hours post burn and a second step at 34 hours post burn.
3. The system according to claim 1 ,
wherein the urinary output error is further multiplied by at least one of a modifier based on a patient's weight and a modifier based on a percentage of a total body surface area burned; and
at least one of the patient's weight and the percentage of the total body surface area burned are obtained from said electronic records system.
4. The system according to claim 1 , wherein the Gaussian function is calculated using
G= 1 −Ae −(X-B) 2 /C 2
where A is set to 1; X is set to the current urinary output; B is set to the mid-point of the target urinary output range; and C is set to 5.
5. The system according to claim 1 , further comprising a timer connected to said processor, said calculating means calculates a new infusion rate when said timer expires after running for a predetermined time.
6. The system according to claim 5 , wherein the predetermined time is based on hours post burn.
7. The system according to claim 1 , further comprising a display, and
said processor further includes
means for driving said display and receiving information from said display of information entered by a user including an infusion rate different than the infusion rate calculated, and
means for controlling operation of said infusion pump at one of the calculated infusion rate and the different infusion rate received from the user until a new infusion rate is received or calculated.
8. The system according to claim 7 , wherein said calculating means sets an initial infusion rate for the patient based on a predetermined formula.
9. The system according to claim 1 , further comprising means for notifying medical staff when a problem has arisen with at least one of the patient and the system.
10. A system for use in resuscitating a patient comprising:
a urine sensor;
an infusion pump;
an electronic medical records system;
a timer; and
a processor connected to said urine sensor, said infusion pump, and said timer, said processor having program code embodied therewith, the program code executable by said processor to
calculate an infusion rate in response to a signal from said timer and based on at least the current infusion rate received from at least one of said infusion pump and said electronic medical records system, the current urinary output received from at least one of said urine sensor and said electronic medical records system, infusion rate model based constants, a patient's weight received from said electronic medical records system, a percentage of total body surface area received from said electronic medical records system, and a Gaussian function centered on a target urinary output, and
wherein the current urinary output is based on at least one of a running average of recent urinary outputs and an extrapolated flow based on recent urinary outputs.
11. The system according to claim 1 , wherein said urine sensor includes a drop rate sensor.
12. The system according to claim 10 , wherein the current urinary output is based on a running average of recent urinary outputs.
13. The system according to claim 10 , wherein the infusion rate model based constants include an infusion rate constant and a urinary output constant.
14. The system according to claim 10 , further comprising a display, and
said processor further having program code embodied therewith, the program code executable by the processor to
drive said display and receiving information from said display of information entered by a user including an infusion rate different than the infusion rate calculated, and
control operation of said infusion pump at one of the calculated infusion rate and the different infusion rate received from the user until a new infusion rate is received or calculated.
15. The system according to claim 10 , wherein calculating the infusion rate uses the following equation
I
t
=
I
t
-
1
+
ⅇ
(
t
)
×
IRC
t
UOC
t
×
Y
weight
×
Y
tbsa
×
G
UO
where I t is the new infusion rate, I t-1 is the last infusion rate, e(t) is the urinary output error, IRC t is the infusion rate constant at time t based on the hours post burn, UOC t is the urinary constant, Y weight is a modifier based on the patient's weight, Y tbsa is a modifier based on the percentage of the total body surface area, and G UO is the Gaussian function based on the target urinary output.
16. The system according to claim 15 , wherein the Gaussian function is calculated using a mid-point of a target urinary output range, where the Gaussian function is calculated using
G= 1 −Ae −(X-B) 2 /C 2
where A is set to 1; X is set to the current urinary output; B is set to the mid-point of the target urinary output range; and C is set to 5.
17. The system according to claim 10 , wherein calculating the infusion rate sets an initial infusion rate for the patient based on a predetermined formula.
18. A system for use in resuscitating a patient comprising:
a urine sensor;
an infusion pump;
a display;
an electronic medical records system;
receiving means for receiving patient data including percentage of total body surface area burned and time since the patient was burned from said electronic medical records system;
first means for calculating an initial infusion rate based on at least the received patient data based on a predetermined formula;
second means for calculating an urinary output error based on a difference between a target urinary output and a current urinary output provided by at least one of said urine sensor and said electronic medical records system, and wherein the current urinary output is based on at least one of a running average of recent urinary outputs and an extrapolated flow based on recent urinary outputs;
third means for calculating a new infusion rate based on at least the calculated urinary output error multiplied by a constant calculated in part based on an exponential function with the input of hours post burn for the patient with the result being added to the current infusion rate;
outputting means for outputting the new infusion rate to at least one of said display, said electronic medical records system, and said infusion pump; and
a timer for controlling the operation of said second means, said third means and said outputting means.
19. The system according to claim 18 , further comprising a processor having said receiving means, said first means, said second means, said third means, and said outputting means.
20. The system according to claim 18 , wherein said third means calculates the infusion rate using the following equation
I
t
=
I
t
-
1
+
ⅇ
(
t
)
×
IRC
t
UOC
t
×
Y
weight
×
Y
tbsa
×
G
UO
where I t is the new infusion rate, I t-1 is the last infusion rate, e(t) is the urinary output error, IRC t is the infusion rate constant at time t based on the hours post burn, UOC t is the urinary constant, Y weight is a modifier based on the patient's weight, Y tbsa is a modifier based on the percentage of the total body surface area, and G UO is the Gaussian function based on the target urinary output; and
the Gaussian function is calculated using a mid-point of a target urinary output range, where the Gaussian function is calculated using
G= 1 −Ae −(X-B) 2 /C 2
where A is set to 1; X is set to the current urinary output; B is set to the mid-point of the target urinary output range; and C is set to 5.