Post on 22-May-2020
RESULTS
Summary • 3 trials, 4–7 segments from each trial.
• Time delays: 0–15 seconds (median: 9.0 s, mean: 6.74 s, stdev: 6.76 s).
• Time constants: 1–15 min (median: 4.20 min, mean: 5.03 min, stdev: 4.05 min).
Examples from 6 segments:
Time Response Comparison
Time (minutes)
Ampl
itude
2 4 6 8 10 12 14 16 186.5
7
7.5
8
8.5
9
9.5
10
10.5
11
11.5Trial 1, zone A. Fit: 77.65 %
Intr
aper
itone
al g
luco
se s
enso
r
Intraarterial sensor filteredthrough estimated transfer functionIntraperitoneal sensor
Time Response Comparison
Time (minutes)
Ampl
itude
5 10 15 20 25 30 355.5
6
6.5
7
7.5
8
8.5
9Trial 1, zone B. Fit: 86.91 %
Intr
aper
itone
al g
luco
se s
enso
r
Intraarterial sensor filteredthrough estimated transfer functionIntraperitoneal sensor
Es<mated linear transfer func<ons (from blood to peritoneum) Based on relaBonship between IA and IP sensor signals.
HP = K1+2.2s HP = K
1+8.3s
Time [minutes]0 5 10 15 20 25 30 35 40
Glu
cose
con
cent
ratio
n es
timat
e [m
mol
/L]
5
6
7
8
9
10
11
12
13
14Trial 1, zone C. T = 14.8 [min]. Delay: 0 [min]. Fit = 70.16 %.
Intraarterial sensorIntraperitoneal sensorGlucose bolusBlood gas analysisSubcutaneous sensor
Time [minutes]0 5 10 15 20 25 30
Glu
cose
con
cent
ratio
n es
timat
e [m
mol
/L]
5
6
7
8
9
10
11
12
13
14Trial 1, zone D. T = 4.4 [min]. Delay: 0 [min]. Fit = 81.75 %.
Intraarterial sensorIntraperitoneal sensorGlucose bolusBlood gas analysisSubcutaneous sensor
Time [minutes]0 5 10 15
Glu
cose
con
cent
ratio
n es
timat
e [m
mol
/L]
4
5
6
7
8
9
10Trial 3, zone F. T = 1.2 [min]. Delay: 0.21 [min]. Fit = 73.86 %.
Intraarterial sensorIntraperitoneal sensorGlucose bolusBlood gas analysisSubcutaneous sensor
Time [minutes]0 2 4 6 8 10 12
Glu
cose
con
cent
ratio
n es
timat
e [m
mol
/L]
5
5.5
6
6.5
7
7.5
8
8.5
9Trial 3, zone E. T = 1.1 [min]. Delay: 0.15 [min]. Fit = 59.21 %.
Intraarterial sensorIntraperitoneal sensorGlucose bolusBlood gas analysisSubcutaneous sensor
C
A
BA
D
B
F
E
REFERENCES
METHODS
INTRAPERITONEAL GLUCOSE SENSING – RAPID AND ACCURATE
Anders Fougner1,2,6, Konstanze Kölle1,2,6, Nils KrisBan Skjærvold1,3,7, Nicolas-‐Andreas Elvemo8, Reinold Ellingsen1,4,8, Sven Magnus Carlsen1,5,7, and Øyvind Stavdahl1,2
anderfo@itk.ntnu.no konstako@itk.ntnu.no nils.k.skjervold@ntnu.no nicolas.elvemo@glucoset.com reinold.ellingsen@ntnu.no sven.carlsen@ntnu.no ostavdahl@itk.ntnu.no
MOTIVATION Animal trials • 3 anaestheBzed non-‐diabeBc pigs • Intravenous infusion of glucose boluses • Glucose level excursions within the range 5–22 mmol/L
Sensor types used in trials • Intraarterial (IA): OpBcal interferometric phenylboronic acid based sensors, placed in the femoral artery [3,4].
• Intraperitoneal (IP): Using the same sensor as in the IA case. Accessed from below the umbilicus through a common port, directed to 4 different posiBons (Fig. on the right). 2–4 sensors per animal.
• Subcutaneous (SC): Off-‐the-‐shelf amperometric enzyme-‐based (glucose oxidase) sensors. Placed on the belly, above the umbilicus.
• Venous blood was sampled and analyzed on a blood gas analyzer (BGA) for reference and calibraBon of the other sensors.
CONCLUSION
Why intraperitoneal sensing? • Subcutaneous glucose sensors: Slow response, poor robustness towards local Bssue effects (mechanical pressure, temperature etc).
• Intravascular glucose sensors: Not pracBcally possible outside of the hospital/clinic.
• We need a rapid, accurate and robust glucose measurement for making a safe arBficial pancreas.
• Intraperitoneal glucose sensors may react faster than subcutaneous sensors [1,2], while being more pracBcally usable than intravascular sensors.
Norwegian University of Science and Technology (NTNU), Trondheim, Norway
• Intraperitoneal glucose sensors can have a substanBally faster and more disBncBve response than subcutaneous sensors.
• Our results indicate that IP sensors may react even faster than previously shown [2].
• Variable dynamics during the experiments + some sensors had to be relocated -‐> Need to invesBgate disturbances & sensor locaBon in more detail.
[1] Velho, G., Froguel, P., and Reach, G., “DeterminaBon of peritoneal glucose kineBcs in rats: implicaBons for the peritoneal implantaBon of closed-‐loop insulin delivery systems,” Diabetologia, vol. 32, no. 6, pp. 331–336, 1989.
[2] Burneo, D. R., Huyeo, L. M., Zisser, H. C., Doyle III, F. J., and Mensh, B. D., ”Glucose Sensing in the Peritoneal Space Offers Faster KineBcs than Sensing in the Subcutaneous Space,” Diabetes, vol. 63, no. 7, pp. 2498–2505, July 2014.
[3] Skjærvold, N. K., Solligård, E., Hjelme, D. R., and Aadahl, P., “ConBnuous measurement of blood glucose: validaBon of a new intravascular sensor,” Anesthesiology, vol. 114, no. 1, 120–125, 2011.
[4] Skjærvold, N. K., Østling, D., Hjelme, D. R., Spigset, O., Lyng, O., and Aadahl, P., “Blood Glucose Control Using a Novel ConBnuous Blood Glucose Monitor and RepeBBve Intravenous Insulin Boluses: ExploiBng Natural Insulin PulsaBlity as a Principle for a Future ArBficial Pancreas,” Interna1onal Journal of Endocrinology, vol. 2013, ArBcle ID 245152, 2013.
6Helse Midt-‐Norge – The Central Norway Regional Health Authority, Norway 7St Olavs University Hospital, Trondheim, Norway 8GlucoSet AS, Trondheim, Norway
1ArBficial Pancreas Trondheim – The APT research group (www.apt-‐norway.com) 2Department of Engineering CyberneBcs 3Department of CirculaBon and Medical Imaging 4Department of Electronics and TelecommunicaBons 5Unit for Applied Clinical Research, Faculty of Medicine
Hydrogel sensor
Incident light
Reflected light
Read-‐out instrument
Interference
OpBcal fiber
Op<cal interferometric sensors
Sensor placement
10 cmIP 10 cm
10 cm10 cm
SC
IAsensor
UL
IPLR
IPLL
IPUR
Glucoseboluses & BGA