Use of a Commercially Available Warming Device to Achieve Normothermia During Continuous Venovenous Hemofiltration in Patients Undergoing Orthotopic Liver Transplant

Abstract

Orthotopic liver transplant (OLT) is associated with a high risk of hypothermia because of introduction of a cold preserved donor liver, transfusion requirements, and a large abdominal incision that may be open for a prolonged period of time. Hypothermia increases the risk of complications, including poor wound healing, infection, and major adverse cardiovascular events.1Slotman GJ Jed EH Burchard KW. Adverse effects of hypothermia in postoperative patients.Am J Surg. 1985; 149: 495-501Abstract Full Text PDF PubMed Scopus (148) Google Scholar Maintaining intraoperative normothermia may be particularly challenging during OLT, and postoperative hypothermia after OLT is common.2Alfonsi P Bekka S Aegerter P. Prevalence of hypothermia on admission to recovery room remains high despite a large use of forced-air warming devices: Findings of a non-randomized observational multicenter and pragmatic study on perioperative hypothermia prevalence in France.PLoS One. 2019; 14e0226038Crossref PubMed Scopus (13) Google Scholar Intraoperative use of continuous venovenous hemofiltration (CVVH) may be required during OLT in patients with acute kidney injury or severe metabolic derangements. Hypothermia is a well-known side effect of CVVH that occurs in 40%-to-50% of patients. Exposure of blood in the extracorporeal circuit to ambient room temperature and administration of cool dialysate and fluids are thought to be responsible for this CVVH-induced hypothermia.3Akhoundi A Singh B Vela M et al.Incidence of adverse events during continuous renal replacement therapy.Blood Purif. 2015; 39: 333-339Crossref PubMed Scopus (64) Google Scholar,4Yagi N Leblanc M Sakai K et al.Cooling effect of continuous renal replacement therapy in critically ill patients.Am J Kidney Dis. 1998; 32: 1023-1030Abstract Full Text PDF PubMed Scopus (65) Google Scholar In our operating rooms, we require 10-foot CVVH tubing to reach the patient during surgery, which prolongs the duration that return blood is exposed to room temperature. We recently used a Ranger High Flow (3M, Saint Paul, MN) fluid warmer set to 41°C to heat the CVVH inflow line in two patients who were receiving intraoperative CVVH during OLT to treat hypothermia. The method proved highly effective and allowed us to warm the patients rapidly and efficiently to normothermia. The use of a CVVH fluid warmer has been reported previously in animal models5Rogiers P Sun Q Dimopoulos G et al.Blood warming during hemofiltration can improve hemodynamics and outcome in ovine septic shock.Anesthesiology. 2006; 104: 1216-1222Crossref PubMed Scopus (23) Google Scholar and in patients who presented to the emergency department with profound hypothermia after exposure,6Scott L Grier L Conrad S. Treatment of severe hypothermia utilizing a veno-venous continuous renal replacement system with a counter current blood warmer.Internet J Emerg Intensive Care Med. 2021; (Available at: http://ispub.com/IJEICM/6/2/13223)Google Scholar and those treated in the intensive care unit.7Rickard CM Couchman BA Hughes M et al.Preventing hypothermia during continuous veno-venous haemodiafiltration: A randomized controlled trial.J Adv Nurs. 2004; 47: 393-400Crossref PubMed Scopus (19) Google Scholar Significant improvement in temperature was observed here, but possible risks also should be considered when using this method, including thrombosis (resulting from increased surface area of the warmer tubing) and inadvertent hyperthermia (considering the set point of 41°C of our fluid warmer). Indeed, as our second case illustrated (Fig 1), we did have to discontinue the CVVH fluid warmer during the case because we were concerned that the patient may become hyperthermic. The hyperthermia risk may be mitigated by using a fluid warmer with a lower set temperature of the fluid warmer, but this is not an option with the Ranger High Flow fluid warmer used at our institution. We believe that the risk of thrombosis is relatively minimal because of the high flow of CVVH (250 mL/min in these cases) and the large-bore high-flow tubing. Our cases suggest that CVVH heating to maintain intraoperative normothermia may prove to be useful in live transplant patients. This work was supported entirely by department funds. The authors have no conflicts of interest pursuant to this report.