Intravenous Fluid Administration and the Coagulation System

Abstract

Intravenous fluid administration in veterinary patients can alter coagulation function by several mechanisms. Both crystalloid and colloid fluids cause hemodilution, reducing platelet count and plasma coagulation protein concentrations. Hemodilution is associated with a hypercoagulable effect at low dilutions and a hypocoagulable effect at higher dilutions. Composition of crystalloid fluids likely has a minor effect, primarily dependent on fluid ion composition. Hypertonic crystalloids may also cause hypocoagulability. Colloids, both synthetic and natural, can cause hypocoagulability by several mechanisms beyond the effects of hemodilution. These include impaired platelet function, decreased plasma coagulation factor activity, impaired fibrin formation and crosslinking, and accelerated fibrinolysis. The vast majority of the veterinary literature investigates the hypocoagulable effects of hydroxyethyl starch–containing fluids using in vitro, experimental, and clinical studies. However, results are inconsistent, likely due to the varying doses and physicochemical properties of the specific fluid products across studies. In addition, some evidence exists for hypocoagulable effects of gelatin and albumin solutions. There is also evidence that these colloids increase the risk of clinical bleeding in people. Limitations of the veterinary evidence for the hypocoagulable effects of colloid fluids include a predominance of in vitro studies and in vivo studies using healthy subjects, which exclude the interaction of the effects of illness. Therefore, clinical relevance of these effects, especially for low-molecular-weight hydroxyethyl starch, is unknown. Firm recommendations about the most appropriate fluid to use in clinical scenarios cannot be made, although it is prudent to limit the dose of synthetic colloid in at-risk patients. Clinicians should closely monitor relevant coagulation assays and for evidence of hemorrhage in at-risk patients receiving any type of fluid therapy, especially in large volumes.

Effects of Hyperbaric Oxygen Therapy on Hemogram, Serum Biochemistry and Coagulation Parameters of Dogs Undergoing Elective Laparoscopic-Assisted Ovariohysterectomy

“…Although crystalloids can dilute coagulation factors, hypercoagulability can also be observed [ 21 ] because of the probable dilution of anticoagulant factors [ 45 ] as well as an increase in BMBT and a reduction in platelet count without reducing platelet aggregation [ 21 ]. However, the literature refers to blood dilutions above 20% of 0.9% NaCl in the blood, that is, in 1:4 mixtures [ 45 ], which is an extremely high volume compared to that used in the surgical groups in our study, with fluid therapy introduced at 10 mL/kg/h [ 22 ] for an average total surgical time of 57.4 ± 2.04 min.…”

Biomarkers of Coagulation and Inflammation in Dogs after Randomized Administration of 6% Hydroxyethyl Starch 130/0.4 or Hartmann’s Solution

“…The second premise for our hypothesis of more hypocoagulability with HES was based on other, non-dilutional, mechanisms by which HES can cause hypocoagulability [ 7 ]. These include platelet dysfunction, [ 27 ] deficiency of vWF and FVIII, [ 13 ] generalized coagulation factor deficiencies, [ 28 ] altered fibrin meshwork structure [ 29 ] with impaired crosslinking, [ 30 ] and enhanced fibrinolysis [ 31 ].…”

“…Significant changes over time were detected, with increasing PT and decreasing coagulation factor activities suggesting a pattern towards hypocoagulability in both groups. Both HES and crystalloid fluids can cause a dilutional coagulopathy proportionate to the degree of hemodilution [ 7 , 8 ]. It is likely that hemodilution increased over time in our study due to the administration of bolus study fluid and other fluid therapy.…”

“…Synthetic colloid solutions may adversely affect coagulation by interfering with platelet function, reducing coagulation factor concentrations, decreasing clot strength, and increasing clot friability [ 7 ]. Evidence of coagulation impairment beyond the expected effects of hemodilution has been demonstrated for low MW HES in experimental studies in dogs, for both in vitro [ 8 , 9 ] and in vivo models of hemorrhage [ 10 ] and sepsis [ 11 ].…”

Hemostatic and thromboelastographic parameters in dogs with renal azotemia

“…In the present study, signs of DIC were observed in seven dogs with AKI, one dog with CKD, and one dog with protein-losing nephropathy. In addition, dilution due to previous fluid therapy can also increase the coagulation time, especially in oliguric patients [12].…”