An interventional study of IscAlert in Ischemia, Blood Circulation Disorder and Carbon Dioxide, sponsored by Oslo University Hospital. Active, not recruiting at 1 site in Norway. Open to participants aged 18 Years to 100 Years. Per ClinicalTrials.gov, last updated 2026-04-28.
Sponsored by Oslo University Hospital · Not applicable, Interventional, and Diagnostic
Investigators will test if changes in CO2 is detected postoperatively in ischemic tissue in a replanted extremity of a traumatically amputated upper or lower extremity. IscAlert is measuring continuously CO2 in muscular and subcutaneous tissue. IscAlert is inserted distal to the operative field into normal muscle and/or subcutaneous tissue in the replanted extremity. Local tissue CO2 and temperature will be monitored continuously postoperatively for the next 10 days. If a reduced or totally obstructed blood flow appear (thrombosis), an increase in tissue CO2 and a lower local temperature will emerge rapidly as a sign of ischemia. This will be detected by the sensor which will alarm the investigators. This will lead to assessment of the replanted extremity and if restricted blood flow is diagnosed, a reoperation will be performed. After reoperation new sensors will be implanted for another ten days if applicable. Sixty patients will be enrolled to undergo the procedures. The IscAlert will be removed from the patient before the patient is discharged from the hospital or a maximum of 10 days (the event that occurs first). 500 devices is planned to be used in this clinical study.
This is an open, prospective, interventional, single-center clinical investigation designed to examine the feasibility and safety of the IscAlert™ device in patients scheduled for extremity replant surgery. Sixty patients will be enrolled to undergo the procedures using a total of 400 devices depending on the injuries.
IscAlert is 0.8 mm in diameter and in vitro testing, shows stable and accurate measurements of pCO2. More than 200 animal experiments have been done with the sensor. The experiments have shown that the sensor detects ischemia (Increased CO2-measurements) in real time in the following organs and tissues: Brain, heart, liver, kidneys, pancreas, intestines, musculature and subcutaneous tissue. Sensitivity and specificity are close to 100%. The sensors are inserted into tissue by a split needle technique. The split needle is the size of a 3-gauge peripheral venous catheter. In animal studies, no complications have been detected when using the sensor.
The IscAlert catheters are connected to an electronics unit that is fixed to the skin with an adhesive plaster or glue outside the sterile area. The electrical signals are redirected to a PC approved for clinical use which continuously records tissue pressures of CO2.
IscAlert is inserted into normal muscle and/or subcutaneous tissue distal on the replanted limb to be operated at the end of surgery or immediate postoperatively. The insertion is far away from the operating field. The insertion is done under sterile conditions in accordance with standard sterility criteria at the hospital. No pain during insertion will occur because of insertion is performed during anesthesia (general or regional). Also, the insertion can be compared to an intramuscular injection.
Postoperatively, the IscAlert sensor will continuously monitoring tissue CO2 and temperature. If ischemia occur, for examples caused by a thrombus, an increase in tissue CO2 and a lower temperature will evolve. This will be detected by the sensor which will alarm the investigators. This will lead to assessment of the replanted extremity and if restricted blood flow is diagnosed or suspected, a reoperation will be performed.
Sixty patients will be enrolled to undergo the procedures. The IscAlert will be removed from the patient before the patient is discharged from the hospital or a maximum of 10 days (the event that occurs first). Approximately 500 devices in 80 injured extremities is planned to be used in this clinical study.
The primary objective is to compare CO2-levels in the replanted extremity in individuals who has undergone extremity replantation surgery and investigate if CO2-level is different in patient diagnosed with obstructed blood flow vs. patients with sufficient blood flow in the replanted extremity.
Our hypotheses are:
545 studies on the registry are indexed under Ischemia; 72 are open to participants now.
This study's planned enrollment of 60 is below the median of 74 across 356 interventional studies indexed under Ischemia.
Browse Ischemia studies →Oslo University Hospital is the lead sponsor of 834 studies on the registry; 149 are open to participants now.
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Exclusion Criteria:
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You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Patients with traumatic amputation of a limb who are undergoing replantation surgery and are monitored postoperatively with IscAlert biosensor measuring local tissue CO2 and temperature in the replanted extremity
Device: IscAlert
Insertion of a CO2- and temperature sensor in the distal part of the replanted extremity
Tissue CO2-level
Tissue CO2-level (kPa) during insertion period
Time frame: 10 days
Bleeding
Amount of blood from insertion site (ml)
Time frame: 10 days
Infection
Infection from insertion site at the discretion of the investigator (yes or no)
Time frame: 30 days
Length of stay at hospital
Number of days from end of initial operation to primary hospital discharge + Number of days from transfer from primary hospital to discharge from secondary hospital.
Time frame: 30 days
Time to reduced blood flow in replanted extremity
Number of days and hours from primary replant surgery end to obstructed blood flow is diagnosed.
Time frame: 10 days
Number of re-operations
Number of reoperations caused by replant necrosis/ischemia in the replanted extremity
Time frame: 30 days
Number of pack-years
Smoking habit; number of pack-years by participants
Time frame: 30 days
Preoperative ischemia time
Preoperative ischemia time of the amputated limb (minutes)
Time frame: 12 hours
Intravenous fluid
Intravenous fluid given during surgery (ml)
Time frame: 12 hours
Vasoactive drugs
Vasoactive drugs given during surgery (microgram)
Time frame: 10 hours
IscAlert functionality
Number of hours with a well-functioning sensor (giving CO2- and temperature data)
Time frame: 10 days
Physical examination of the reimplanted extremity - capillary filling
Time of capillary filling (seconds)
Time frame: 10 days
Physical examination of the reimplanted extremity - color
Color of reimplanted extremity (Red or Pale)
Time frame: 10 days
Physical examination of the reimplanted extremity - temperature
Temperature of reimplanted extremity (degrees Celsius)
Time frame: 10 days
Plan to share: No — No plan to share IPD to other researchers
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This study is active, not recruiting, as verified in Apr 2026. You cannot join it, but the record below documents what was studied.
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