title: Laboratory study on the kinetics of the warming of cold fluids-A hot topic.
abstract: OBJECTIVE
  In case of mild therapeutic hypothermia after an out-of-hospital cardiac arrest, several techniques could limit the cold fluid rewarming during its perfusion. We aimed to evaluate cold fluid temperature evolution and to identify the factors responsible for rewarming in order to suggest a prediction model of temperature evolution.
  
  
  METHODS
  This was a laboratory experimental study. We measured temperature at the end of the infusion line tubes (ILT). A 500ml saline bag at 4°C was administered at 15 and 30ml/min, with and without cold packs applied to the cold fluid bag or to the ILT. Cold fluid temperature was integrated in a linear mixed model. Then we performed a mathematical modelization of the thermal transfer across the ILT.
  
  
  RESULTS
  The linear mixed model showed that the mean temperature of the cold fluid was 1°C higher (CI 95%: [0.8-1.2]) with an outflow rate of 15 versus 30ml/min (P<0.001). Similarly, the mean temperature of the cold fluid was 0.7°C higher (CI 95%: [0.53-0.9]) without cold pack versus with cold packs (P<0.001). Mathematical modelization of the thermal transfer across the ILT suggested that the cold fluid warming could be reduced by a shorter and a wider ILT. As expected, use of CP has also a noticeable influence on warning reduction. The combination of multiple parameters working against the rewarming of the solution should enable the infusion of a solute with retained caloric properties.
  
  
  CONCLUSIONS
  By limiting this "ILT effect," the volume required for inducing mild therapeutic hypothermia could be reduced, leading to a safer and a more efficient treatment.
authors.affiliation: Paris Fire Brigade Emergency Medical Department, BMU, BSPP, 1, place Jules Renard, 75017 Paris, France. Electronic address: alexandre.mendibil@gmail.com.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Mendibil
authors.affiliation: Paris Fire Brigade Emergency Medical Department, BMU, BSPP, 1, place Jules Renard, 75017 Paris, France.
authors.forename: Daniel
authors.initials: D
authors.lastname: Jost
authors.affiliation: Fire engineering section, Physics and fire engineering division at the Central Laboratory of the Prefecture of Police of Paris (LCPP), 39 bis, rue de Dantzig, 75015 Paris, France.
authors.forename: Aurélien
authors.initials: A
authors.lastname: Thiry
authors.affiliation: Fire engineering section, Physics and fire engineering division at the Central Laboratory of the Prefecture of Police of Paris (LCPP), 39 bis, rue de Dantzig, 75015 Paris, France.
authors.forename: Delphine
authors.initials: D
authors.lastname: Garcia
authors.affiliation: Paris Fire Brigade Emergency Medical Department, BMU, BSPP, 1, place Jules Renard, 75017 Paris, France.
authors.forename: Julie
authors.initials: J
authors.lastname: Trichereau
authors.affiliation: Paris Fire Brigade Emergency Medical Department, BMU, BSPP, 1, place Jules Renard, 75017 Paris, France.
authors.forename: Benoit
authors.initials: B
authors.lastname: Frattini
authors.affiliation: Paris Fire Brigade Emergency Medical Department, BMU, BSPP, 1, place Jules Renard, 75017 Paris, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Dang-Minh
authors.affiliation: Paris Fire Brigade Emergency Medical Department, BMU, BSPP, 1, place Jules Renard, 75017 Paris, France.
authors.forename: Olga
authors.initials: O
authors.lastname: Maurin
authors.affiliation: Paris Fire Brigade Emergency Medical Department, BPIB, BSPP, 1, avenue Guy Moquet, 94460 Valenton, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Margerin
authors.affiliation: Paris Fire Brigade Emergency Medical Department, BMU, BSPP, 1, place Jules Renard, 75017 Paris, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Domanski
authors.affiliation: Paris Fire Brigade Emergency Medical Department, BMU, BSPP, 1, place Jules Renard, 75017 Paris, France.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Tourtier
mesh_terms: D000465:Algorithms; D003080:Cold Temperature; D005440:Fluid Therapy / Q000379:methods*; D006801:Humans; D007262:Infusions, Intravenous; D007700:Kinetics; D008962:Models, Theoretical; D058687:Out-of-Hospital Cardiac Arrest / Q000628:therapy; D011237:Predictive Value of Tests; D017694:Rewarming; D013696:Temperature
keywords: Cold saline; Induced hypothermia; Laboratory; Postresuscitation care; Temperature