The effect of 3 resuscitative fluid therapies on hemostasis as measured by rotational thromboelastometry in dogs

Assessment of hemostasis in dogs with gastric-dilation-volvulus, during resuscitation with hydroxyethyl starch (130/0.4) or hypertonic saline (7.5%)

OBJECTIVE

To compare the impact of an IV bolus of hydroxyethyl starch 130/0.4 (HES) or hypertonic saline 7.5% (HS) on hemostasis in dogs resuscitated for gastric-dilation-volvulus (GDV).

DESIGN

Open-label, parallel-group randomized clinical trial.

ANIMALS

Twenty-three client-owned dogs.

INTERVENTIONS

Dogs affected by GDV and shock were randomly assigned to receive HES at 10 mL/kg or HS at 4 mL/kg every 15 minutes. Blood samples were collected for blood gas analysis, PCV, total plasma protein, albumin, standard coagulation profile, and thromboelastometry (ROTEM) at baseline (T0) and at the end of bolus (T1). To assess the differences between the 2 groups at T1, Student's t-test or Wilcoxon rank-sum test was used. To evaluate the differences between T0 and T1, ANOVA for paired data or Wilcoxon matched-pairs signed-ranks test was used. P < 0.05 was considered significant.

MEASUREMENT AND MAIN RESULTS

Hemostasis was evaluated by means of prothrombin time, activated partial thromboplastin time, fibrinogen, and ROTEM. The study included 13 dogs in the HES group and 10 dogs in the HS group. Differences were found between groups at T1: increase in clotting time (P = 0.018) and decrease in fibrinogen level (P = 0.021) in the HS-treated group. Between T0 and T1, there were differences for the HES group: increase in clot formation time (P = 0.046), decrease in maximum clot firmness (P = 0.002) in ex-TEM profile, and decrease in maximum clot firmness (P = 0.0117) in fib-TEM profile. Between T0 and T1, the following differences were noted for the HS group: increase in clotting time (P = 0.048) and clot formation time (P = 0.0019), decrease in maximum clot firmness (P = 0.031) and α angle (P = 0.036) in ex-TEM profile, decrease in α angle (P = 0.036) in in-TEM profile, and decrease in maximum clot firmness (P = 0.017) in fib-TEM profile.

CONCLUSION

In dogs affected by GDV, HES or HS infusion caused a similar tendency toward hypocoagulability, with few differences between the 2 groups.

Haemostatic changes associated with fluid resuscitation in canine parvoviral enteritis

The haemostatic status of dogs with canine parvovirus (CPV) enteritis, within 24 h of admission after initial fluid administration, has been described previously, but the haemostatic status at admission and after standard fluid resuscitation, as well as after initial fluid redistribution, has not been investigated previously. The objective of this study was to characterise the haemostatic status at admission and describe the effect of crystalloid fluid resuscitation on haemostatic variables in dogs with CPV enteritis. Twenty-seven client-owned, hospitalised dogs with confirmed natural CPV infection and 15 healthy age-matched controls were included in a prospective, observational clinical study. The volume of resuscitation fluid, haematocrit (HCT), platelet count, thromboelastography (TEG) variables, antithrombin (AT) activity, fibrinogen- and C-reactive protein (CRP) concentrations were measured in all dogs at admission, after fluid resuscitation and, in 10 dogs, after receiving an additional 3 hours of maintenance-rate crystalloid fluids. For the CPV group at admission, the median TEG reaction time (R) and maximum amplitude (MA) or clot strength, as well as the median HCT, fibrinogen and CRP concentrations, were significantly increased compared to the controls. After fluid resuscitation, median R was significantly shorter, MA significantly increased and HCT and AT activity significantly decreased compared to admission values. The haemostatic variables remained unchanged after 3 h of maintenance-rate crystalloid therapy. The increased clot strength present in dogs with CPV enteritis at admission was exacerbated after fluid resuscitation and persisted for hours after large-volume crystalloid fluid administration.

Examining the Effect of Hypertonic Saline Administered for Reduction of Intracranial Hypertension on Coagulation

BACKGROUND

Hypertonic saline (23.4%, HTS) bolus administration is common practice for refractory intracranial hypertension, but its effects on coagulation are unknown. We hypothesize that 23.4% HTS in whole blood results in progressive impairment of coagulation in vitro and in vivo in a murine model of traumatic brain injury (TBI).

STUDY DESIGN

For the in vitro study, whole blood was collected from 10 healthy volunteers, and citrated native thrombelastography was performed with normal saline (0.9%, NS) and 23.4% HTS in serial dilutions (2.5%, 5%, and 10%). For the in vivo experiment, we assessed the effects of 23.4% HTS bolus vs NS on serial thrombelastography and tail-bleeding times in a TBI murine model (n = 10 rats with TBI and 10 controls).

RESULTS

For the in vitro work, clinically relevant concentrations of HTS (2.5% dilution) shortened time to clot formation and increased clot strength (maximum amplitude) compared with control and NS. With higher HTS dosing (5% and 10% blood dilution), there was progressive prolongation of time to clot formation, decreased angle, and decreased maximum amplitude. In the in vivo study, there was no significant difference in thrombelastography measurements or tail-bleeding times after bolus administration of 23.4% HTS compared with NS at 2.5% blood volume.

CONCLUSIONS

At clinically relevant dilutions of HTS, there is a paradoxical shortening of time to clot formation and increase in clot strength in vitro and no significant effects in a murine TBI model. However, with excess dilution, caution should be exercised when using serial HTS boluses in TBI patients at risk for trauma-induced coagulopathy.