title: The effectiveness of low-dose desmopressin in improving hypothermia-induced impairment of primary haemostasis under influence of aspirin - a randomized controlled trial.
abstract: BACKGROUND
  Mild hypothermia (34-35 °C) increases perioperative blood loss. Our previous studies showed that desmopressin could have in vitro beneficial effects on hypothermia-induced primary haemostasis impairment. In this study, we investigate the in vitro effects of desmopressin on hypothermia-induced primary haemostasis impairment under the influence of aspirin in healthy volunteers.
  
  
  METHODS
  Sixty healthy volunteers were randomly allocated to taking aspirin 100 mg or placebo for three days. On the sixth day blood samples were taken before and after the injection of desmopressin (1.5 microgram or 5 microgram) or normal saline subcutaneously. Measurements including Platelet Function Analyzer (PFA-100®) closure times, plasma von Willebrand Factor antigen, haemoglobin and platelet levels were made at 32 °C and 37 °C respectively.
  
  
  RESULTS
  Collagen/epinephrine closure time (EPICT) was significantly prolonged by 21.13 % (95 %CI 2.34-39.74 %, p = 0.021) in aspirin group at 37 °C. While hypothermia alone prolonged both collagen/adenosine diphosphate (ADPCT) and EPICT by 17.63 % (95 %CI 13.5-20.85 %, p < 0.001) and 8.0 % (95 %CI 6.38-10.04 %, p = 0.024) respectively, addition of aspirin only further prolonged EPICT by 19.9 % (95 %CI 3.32-36.49 %, p = 0.013). In aspirin group, desmopressin 1.5 microgram and 5 microgram significantly reduced ADPCT to below baseline levels at 37 °C (p = 0.025 and <0.001 respectively), whereas reduction in EPICT was seen with desmopressin 5 microgram (p =0.008). The effect was less pronounced at 32 °C, with a significant reduction in EPICT obtained with a dosage of 5 microgram only (p = 0.011).
  
  
  CONCLUSIONS
  It was shown that aspirin could further potentiate the hypothermia-induced closure time prolongations. Low dose desmopressin (1.5 microgram) reduced PFA-100® closure times towards baseline. A higher dosage (5 microgram) further reduced the closure times below baseline. Therefore low dose desmopressin (1.5 microgram) might have the potential to correct hypothermia-induced primary haemostasis impairment under the influence of aspirin during the perioperative period.
  
  
  BACKGROUND
  ClinicalTrials.gov: NCT01382134.
authors.affiliation: Department of Anaesthesia, Pamela Youde Nethersole Eastern Hospital, Chai Wan, Hong Kong, SAR, China. fifitsui@gmail.com.
authors.forename: Pui Yee
authors.initials: PY
authors.lastname: Tsui
authors.affiliation: Department of Anaesthesiology, The University of Hong Kong, Room K424, 4th Floor, K Block, Queen Mary Hospital, 102 Pokfulam Road, Pokfulam, Hong Kong, SAR, China. cheucw@hku.hk.
authors.forename: Chi Wai
authors.initials: CW
authors.lastname: Cheung
authors.affiliation: Department of Anaesthesiology, The University of Hong Kong, Room K424, 4th Floor, K Block, Queen Mary Hospital, 102 Pokfulam Road, Pokfulam, Hong Kong, SAR, China. yves@hku.hk.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Lee
authors.affiliation: Department of Pharmacology & Pharmacy, The University of Hong Kong, Hong Kong, SAR, China. swsleung@hku.hk.
authors.forename: Susan Wai Sum
authors.initials: SW
authors.lastname: Leung
authors.affiliation: Department of Anaesthesiology, The University of Hong Kong, Room K424, 4th Floor, K Block, Queen Mary Hospital, 102 Pokfulam Road, Pokfulam, Hong Kong, SAR, China. drjkfng@gmail.com.
authors.forename: Kwok Fu Jacobus
authors.initials: KF
authors.lastname: Ng
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D001241:Aspirin / Q000008:administration & dosage / Q000494:pharmacology*; D003094:Collagen / Q000378:metabolism; D003894:Deamino Arginine Vasopressin / Q000008:administration & dosage / Q000494:pharmacology*; D004311:Double-Blind Method; D004837:Epinephrine / Q000378:metabolism; D005260:Female; D005500:Follow-Up Studies; D006487:Hemostasis / Q000187:drug effects; D006490:Hemostatics / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D007035:Hypothermia / Q000150:complications*; D008297:Male; D010979:Platelet Function Tests
chemical_list: D006490:Hemostatics; D000244:Adenosine Diphosphate; D003094:Collagen; D003894:Deamino Arginine Vasopressin; D001241:Aspirin; D004837:Epinephrine