Can transcutaneous near infrared spectroscopy detect severe hepatic ischemia: a juvenile porcine model.
BACKGROUND
Vascular complications following pediatric liver transplantation occur in 8-10% of cases, and no continuous, non-invasive monitoring for this problem exists. Near infrared spectroscopy (NIRS) allows non-invasive, continuous, transcutaneous assessment of hemoglobin oxygenation (StO2) 1-4 cm below the skin surface.


OBJECTIVE
We hypothesized that transcutaneous NIRS would be able to detect severe hepatic ischemia, and tested this in an animal model using 15-20 kg and 5-7 kg juvenile pigs.


METHODS
Direct liver surface and transcutaneous hepatic tissue hemoglobin oxygen saturation (StO2) were measured during occlusions of the hepatic artery and portal vein. Changes in hepatic delivery of oxygen (HepDO2) were calculated for each ischemic challenge and compared to changes in direct liver surface (DirHepStO2) and transcutaneous liver StO2measurements (CutHepStO2).


RESULTS
In the 15-20 kg animals during complete occlusion, CutHepStO2decreased by 6.0(±4.9)%, whilst DirHepStO2decreased by 83.7(±7.2)%. In the 5-7 kg animals during complete occlusion, CutHepStO2decreased by 27.4(±8.5)%, whilst DirHepStO2decreased by 82.8(±4.6)%.


CONCLUSIONS
Transcutaneous hepatic StO2monitoring cannot reliably detect severe hepatic ischemia in a juvenile porcine model, although a stronger and potentially useful signal is seen in 5-7 kg pigs. Trials of this technology should be currently restricted to situations where the organ is less than 1 cm from the skin surface, corresponding to infants of <10 kg.
Department of Anaesthesia, The Children's Hospital at Westmead, Sydney, NSW, Australia.|Discipline of Pediatrics and Child Health, University of Sydney, Sydney, NSW, Australia.
Justin J
http://orcid.org/0000-0002-4398-2150
JJ
Skowno
Discipline of Pediatrics and Child Health, University of Sydney, Sydney, NSW, Australia.|Department of Surgery, The Children's Hospital at Westmead, Sydney, NSW, Australia.
Jonathan S
JS
Karpelowsky
Department of Anaesthesia, The Children's Hospital at Westmead, Sydney, NSW, Australia.|Paediatric Intensive Care Unit, The Children's Hospital at Westmead, Sydney, NSW, Australia.|Division of Critical Care and Trauma, The George Institute for Global Health, Sydney, NSW, Australia.
Nicola R
NR
Watts
Discipline of Pediatrics and Child Health, University of Sydney, Sydney, NSW, Australia.|Department of Orthopedic Surgery, The Children's Hospital at Westmead, Sydney, NSW, Australia.
David G
DG
Little
D000818:Animals; D004195:Disease Models, Animal; D007511:Ischemia / Q000000981:diagnostic imaging*; D008099:Liver / Q000098:blood supply* / Q000000981:diagnostic imaging*; D008297:Male; D015203:Reproducibility of Results; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D013552:Swine
liver transplantation; monitoring; pediatric; postoperative; vascular complications