Effects of goal-directed fluid therapy with different lactated Ringer's: hydroxyethyl starch ratios in hemorrhagic shock dogs

Noninvasive assessment of fluid responsiveness for emergency abdominal surgery in dogs with pulmonary hypertension: Insights into high-risk companion animal anesthesia

Objective

Optimizing cardiac stroke volume during high-risk surgical anesthesia is of particular interest with regard to a therapeutic target to reduce the incidence of postoperative complications. However, intensive fluid management in critically ill small animals with pulmonary hypertension (PH) has been empirically performed, and thus it can be challenging. Stroke volume variation (SVV) has been used as a dynamic preload predictor of fluid responsiveness. We hypothesized that if SVV exhibited robust reliability in the setting of hemodynamically unstable condition, it would provide more precise information on fluid resuscitation to translate it into veterinary anesthesia. Thus the aim of this study was to investigate the utility of SVV measured by the electrical velocimetry (EV) method for predicting fluid responsiveness in dogs with PH.

Methods

Sixteen dogs undergoing emergency abdominal surgery and diagnosed with PH secondary to myxomatous mitral valve disease (MMVD) on preoperative transthoracic echocardiogram were included. Dogs were randomly assigned to 2 groups with and without inotropic cardiac support with dobutamine. Hemodynamic measurements including stroke volume and SVV derived from the EV device were performed under general anesthesia before (baseline) and after surgery (fluid challenge with a colloid solution defined by a SV increase of ≥ 10%).

Results

In both groups, SVV elevated significantly after abdominal surgery compared with baseline. In dobutamine infused group, the SVV values decreased significantly after fluid challenge (P < 0.05) with a greater number of responders than saline infused control group (P < 0.01). Receiver operating curve analysis of SVV confirmed high positive predictive value for dogs during dobutamine infusion (P < 0.05; cut-off value of 15%; specificity 90%, sensitivity 82%).

Conclusions

Noninvasive EV monitoring may be useful for the prediction of fluid responsiveness in critically ill dogs with left-sided heart failure-related PH. This normalization of dynamic preload indices, which could be achieved more precisely under inotropic support, may prevent further detrimental consequence of fluid loading.

Fluid resuscitation after severe trauma injury : U-shaped associations between tetrastarch dose and survival time or frequency of acute kidney failure

BACKGROUND

Using tetrastarch for fluid resuscitation after a severe trauma injury may increase risks of death and acute kidney injury. The importance of tetrastarch dose, however, is unknown.

METHODS

A retrospective observational study was performed in two trauma centres using data on type and amount of fluids (balanced crystalloids or tetrastarch) used for pre- and acute in-hospital shock management. We evaluate independent associations between the relative and absolute volumes of tetrastarch and 90-day survival time or the frequency of severe acute kidney failure (AKF).

RESULTS

We studied 271 patients who had sustained a severe blunt trauma injury (average predicted mortality according to the Revised Injury Severity Classification Score (RISC) 15.1 ± 1.4% [mean, standard deviation]), and who had required more than 2 days of intensive care therapy. In all, 75.3% of patients had received tetrastarch with a crystalloid/colloid ratio of 2.93 ± 2.60. The 90-day mortality was 11.1%, and 7.8% of the patients developed severe AKF. After adjusting for confounders, we found a U-shaped, nonlinear association between absolute or relative volumes of tetrastarch and survival time (p = 0.003 and 0.025, respectively). Optimal relative volumes of tetrastarch approximately ranged from 20 to 30% of total fluids. Giving less than about 1000 ml, or more than about 2000 ml tetrastarch was significantly associated with an increased risk of developing severe AKF (p = 0.023).

CONCLUSIONS

There was a complex U‑shaped association between the tetrastarch dose and morbidity/mortality of patients after a severe trauma injury. The optimal crystalloid/tetrastarch ratio for acute shock management appears to range from about 2.5 to 4.0.

Lactated Ringer' Solution may be Superior to Saline-Based 6% Hydroxyethyl Starch 130/0.4 for Early Resuscitation within 12 hours from Hemorrhagic Shock

Purpose: To compare the effects of fluid resuscitation with lactated Ringer's solution (LR) and saline-based 6% hydroxyethyl starch 130/0.4 (HES) on the inflammatory response and oxidative stress in the small intestine as well as on bacterial translocation to the liver. Methods: Sprague-Dawley rats were subjected to blood pressure-controlled hemorrhagic shock and then resuscitated with LR or HES. At 1, 3, 6, 12, and 24 hr after resuscitation, liver tissues were collected to count the bacterial colonies, and small intestines were harvested to analyze the levels of inflammatory (TNF-α and HO-1) and oxidative stress (MPO) mediators as well as the intestinal injury by immunohistochemistry, colorimetry and hematoxylin & eosin staining, respectively. Results: The expression level of TNF-α in the LR group was stable from 1 to 6 hr but decreased at 12 hr and then abruptly increased at 24 hr. The expression level of TNF-α in the LR group was significantly lower than that in the HES group, especially during the first 12 hr post-fluid infusion. MPO activity decreased to its lowest level at 3 hr but increased from 6 to 12 hr, with no difference at 24 hr between the two groups. Although a decreasing tendency was observed from 6 hr, HO-1 expression levels remained higher in the LR group than in the HES group at 12 and 24 hr, particularly at 12 hr. During the initial 12 hr, the LR group exhibited significantly lower colony-forming units in the liver tissues than the HES group. Chiu's score in the intestine decreased regardless of which resuscitative fluids were used. Conclusions: During early resuscitation (within 12 hr), LR may be superior to HES in reducing intestinal injuries by suppressing inflammatory and oxidative mediators.

Changes in Serum Creatinine Concentration and Acute Kidney Injury (AKI) Grade in Dogs Treated with Hydroxyethyl Starch 130/0.4 From 2013 to 2015

BACKGROUND

Hydroxyethyl starch (HES) solutions may cause acute kidney injury (AKI) in humans.

OBJECTIVE

To compare AKI grades in 94 dogs exposed and 90 dogs that were unexposed to 6% HES-130/0.4.

ANIMALS

Dogs receiving 6% HES-130/0.4 (HES cohort) or crystalloids (unexposed cohort) between 2013 and 2015.

METHODS

Historical cohort study. Diagnosis, total cumulative dose and total mL/kg of HES administered, time frame of HES administration and serum creatinine concentrations up to 90 days after initiation of HES treatment were retrospectively reviewed. The AKI grades were retrospectively determined by IRIS guidelines.

RESULTS

Exposed dogs received a median cumulative dose of 69.4 mL/kg (range, 2-429 mL/kg) HES over a median of 4 (range, 1-16) days, resulting in a median dose of 20.7 (range, 2-87) mL/kg/d. Although the cohorts differed in terms of age and diagnosis, AKI grades were not significantly different at the evaluated short- and long-term time points. Results of ordinal logistic regression identified the number of days of HES administration as significantly associated with an increase in AKI grade within 10 days (P = .038), whereas there was no significant association among HES exposure, HES mL/kg/d, and an increase in AKI grade.

CONCLUSIONS AND CLINICAL IMPORTANCE

HES-130/0.4-treated dogs were not more prone to develop AKI than HES-untreated, but the number of HES days was significantly associated with an increase in AKI grade within 10 days post-HES administration. The time frame of HES treatment should be kept short. Prospective, randomized clinical trials are required to assess the effect of HES on renal function in dogs.

Maraviroc-Mediated Lung Protection following Trauma-Hemorrhagic Shock

Objectives. The peroxisome proliferator-activated receptor gamma (PPARγ) pathway exerts anti-inflammatory effects in response to injury. Maraviroc has been shown to have potent anti-inflammatory effects. The aim of this study was to investigate whether PPARγ plays an important role in maraviroc-mediated lung protection following trauma-hemorrhage. Methods. Male Sprague-Dawley rats underwent trauma-hemorrhage (mean blood pressure maintained at approximately 35-40 mmHg for 90 minutes), followed by fluid resuscitation. During resuscitation, a single dose of maraviroc (3 mg/kg, intravenously) with and without a PPARγ inhibitor GW9662 (1 mg/kg, intravenously), GW9662, or vehicle was administered. Lung water content, tissue histology, and other various parameters were measured (n = 8 rats/group) 24 hours after resuscitation. One-way ANOVA and Tukey's testing were used for statistical analysis. Results. Trauma-hemorrhage significantly increased lung water content, myeloperoxidase activity, intercellular adhesion molecule-1, interleukin-6, and interleukin-1β levels. These parameters significantly improved in the maraviroc-treated rats subjected to trauma-hemorrhage. Maraviroc treatment also decreased lung tissue damage as compared to the vehicle-treated trauma-hemorrhaged rats. Coadministration of GW9662 with maraviroc abolished the maraviroc-induced beneficial effects on these parameters and lung injury. Conclusion. These results suggest that PPARγ might play a key role in maraviroc-mediated lung protection following trauma-hemorrhage.