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Evaluation of a third generation hydroxyethyl starch (Tetrastarch), in comparison to Lactated Ringer's Solution (LRS), as a volume replacement fluid in healthy dogs undergoing acute normovolemic hemodilution

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Author(s):
Miriely Steim Diniz
Total Authors: 1
Document type: Doctoral Thesis
Press: Botucatu. 2017-03-24.
Institution: Universidade Estadual Paulista (Unesp). Faculdade de Medicina. Botucatu
Defense date:
Advisor: Francisco José Teixeira Neto
Abstract

Rationale: Synthetic colloids such as tetrastarch solution (TS), when compared to crystalloids, are more effective plasma expanders and minimize the risk of edema. However, TS may cause adverse effects on coagulation and, in septic patients, may increase the risk of acute kidney injury (AKI) and death. Hypotheses: The first hypothesis was that, in healthy dogs, acute normovolemic hemodilution (ANH) with TS would not induce AKI; while the coagulation impairment induced by this colloid would be at least equivalent to that induced by lactated Ringer´s solution (LRS). The second hypothesis was that ANH with TS, when compared to ANH with LRS, would cause less extravascular lung water accumulation and less evidence of peripheral edema. Material and Methods: Six dogs (19.7–35.3 kg) were anesthetized with isoflurane/remifentanil on 3 occasions. During the first occasion (Phase I), animals did not undergo ANH (control). During Phase II, initiated after an interval of at least 2-weeks, the same dogs underwent anesthesia for ANH on 2 occasions, in a ramdomized crossover design (washout interval > 8-weeks). During both procedures, the blood withdrawn was replaced with LRS or TS (3 mL of LRS or 1 mL of TS for each 1 mL of blood removed), during 60 minutes, aiming to decrease the hematocrit to 33%. Anesthesia was maintained for 4 hours after volume replacement (VR). Cardiorespiratory variables were recorded at BL (before ANH), 0.5, 1, 2, 3, and 4 hours after VR. Biomarkers of AKI were measured at BL, 4, 24, and 72 hours after ANH. Hemostasis was assessed at BL, 0.5, 2, 4, and 24 hours after VR. Results: In the TS treatment, the extra-vascular lung water index (EVLWI) observed 1 hour after VR was significantly smaller (P < 0.05) than in controls. At 4 hours after VR, the EVLWI in the TS treatment was significantly smaller than in the LRS treatment. The arterial oxygen partial pressure/inspired oxygen fraction ratio did not differ among treatments (P > 0.05) between 0.5–4 hours after VR. Head edema was observed in 3/6 dogs in the LRS treatment only. The Neutrophil gelatinase-associated lipocalin/creatinine ratio in urine did not differ among treatments and was lower than the threshold for detecting AKI (120.000 pg/mg) during 72 hours after VR. Clot formation time significantly increased from controls for a longer period in the LRS treatment (between 0.5–4 hours after VR) than in the TS treatment (between 0.5–2 hours after RV). Maximum clot firmness significantly decreased from controls for the same time period for both fluids (between 0.5–4 hours after VR). No significant differences were found for buccal mucosal bleeding time after VR. Conclusions: The use of TS in healthy dogs undergoing ANH, in addition to not producing evidence of AKI, causes a transient dilutional coagulopathy that is at least similar to that produced by ANH with LRS. In as much as TS results in less extra-vascular lung water accumulation than LRS, and does not produce evidence of peripheral edema, the use of TS as a volume replacement fluid in the ANH setting is favored in comparison to LRS. (AU)

FAPESP's process: 15/04810-2 - Comparison of Tetrastarch and Lactated Ringers as volume replacement fluids in dogs undergoing acute normovolemic hemodylution
Grantee:Miriely Steim Diniz
Support Opportunities: Scholarships in Brazil - Doctorate