Testing the effect of a new pleural catheter "HeatCath" for the treatment of moderate hypothermia in a porcine model
Authors
Friis, Jens Peter ; Nørgaard, Mathis Huse
Term
5. Term (Master thesis)
Education
Publication year
2023
Submitted on
2023-01-04
Pages
17
Abstract
This study tested a new central warming catheter, HeatCath, designed to treat and support patients with moderate accidental hypothermia (dangerously low body temperature), in a porcine model. We assessed HeatCath by measuring the rewarming rate in degrees Celsius per hour and comparing it with the best available technique reported in the literature. A target rate was defined from the literature. Methods: Two anesthetized pigs (49–53 kg) were prepared for ECMO (a heart–lung support circuit) and cooled to 26 °C. Core temperature was measured with catheters in the bladder and abdomen. One pig was randomized to intervention and rewarmed for 3.5 hours using HeatCath; the other served as a control without active rewarming during the same period. After 195 minutes, HeatCath was also applied to the control pig to assess practicality and rewarming rate at the prevailing temperature. Results: The literature review identified pleural lavage (washing the chest cavity with warm fluid) as the best current method, with a rewarming rate of 2.8 °C/h; this became the target for HeatCath. Over 195 minutes, the average rewarming rate was 1.3 °C/h with HeatCath versus 0.4 °C/h without active treatment. During rewarming, the intervention animal had a higher mean arterial pressure (71 mmHg ± 8) than the control (61 mmHg ± 7), with similar heart rates (~57 bpm). Starting HeatCath on the control after 195 minutes at 27.1 °C produced 1.1 °C/h over 60 minutes. Conclusion: In this pig model, HeatCath provided controlled internal rewarming faster than no active treatment and with more stable vital signs, but it did not reach the literature-based target of 2.8 °C/h. Further development of HeatCath appears warranted.
Formålet med studiet var at afprøve en ny central opvarmningskateter, HeatCath, til behandling og støtte af patienter med moderat utilsigtet hypotermi (farligt lav kropstemperatur), i et forsøg på grise. Vi vurderede HeatCath ved at måle opvarmningshastighed i grader Celsius pr. time og sammenligne med data fra den bedste kendte metode i litteraturen. En mål-hastighed blev defineret ud fra litteraturen. Metode: To bedøvede grise (49–53 kg) blev klargjort til ECMO (en hjerte-lungestøttende kreds) og nedkølet til 26 °C. Kernetemperaturen blev målt med katetre i blæren og i bughulen. Én gris blev randomiseret til intervention og opvarmet i 3,5 timer med HeatCath; den anden fungerede som kontrol uden aktiv opvarmning i samme periode. Efter 195 minutter blev HeatCath også anvendt på kontrolgrisen for at vurdere praktikalitet og opvarmningshastighed ved den givne temperatur. Resultater: Litteraturgennemgangen identificerede pleural skylning (skylning af brysthulen med varmt væske) som den bedste samtidige metode med en opvarmningshastighed på 2,8 °C/time; dette blev mål for HeatCath. I forsøgsperioden på 195 minutter var den gennemsnitlige opvarmningshastighed 1,3 °C/time med HeatCath mod 0,4 °C/time uden aktiv behandling. Under opvarmning havde interventionsdyret højere middelarterietryk (71 mmHg ± 8) end kontrol (61 mmHg ± 7), mens pulsen var ens (~57 slag/min). Da HeatCath blev startet på kontroldyret efter 195 minutter ved 27,1 °C, var opvarmningshastigheden 1,1 °C/time over 60 minutter. Konklusion: I denne svinemodel gav HeatCath en kontrolleret intern opvarmning hurtigere end ingen aktiv behandling og med mere stabile vitale tegn, men nåede ikke det litteraturbaserede mål på 2,8 °C/time. En videreudvikling af HeatCath kan derfor være gavnlig.
[This apstract has been rewritten with the help of AI based on the project's original abstract]
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