Septic Shock In Dogs Research Articles

Evaluation of the Effect of Induced Endotoxemia on ROTEM S® and Platelet Parameters in Beagle Dogs Anaesthetized with Sevoflurane.

Endotoxemia is thought to induce severe changes in coagulation status. In this study, blood samples from six beagle dogs receiving 1 mg/kg E. coli lipopolysaccharide (LPS) intravenously were analyzed to describe the concurrent changes in platelet count, platelet function assessed with impedance thromboaggregometry, thromboelastometry and d-dimers during artificially induced endotoxemia and its therapy with fluids and vasopressors at five timepoints (baseline, after LPS and 30 mL/kg Ringer's acetate, during noradrenaline ± dexmedetomidine infusion, after a second fluid bolus and a second time after vasopressors). Results were analyzed for changes over time with the Friedman test, and statistical significance was set at p < 0.05. We found decreased platelet count and function and changes in all platelet-associated rotational thromboelastometry (ROTEM) variables indicating hypocoagulability, as well as increases in d-dimers indicating fibrinolysis within one hour of intravenous administration of LPS, with partial recovery of values after treatment and over time. The fast changes in platelet count, platelet function and ROTEM variables reflect the large impact of endotoxemia on the coagulation system and support repeated evaluation during the progress of endotoxemic diseases. The partial recovery of the variables after initiation of fluid and vasopressor therapy may reflect the positive impact of the currently suggested therapeutic interventions during septic shock in dogs.

Clinical features and outcome of septic shock in dogs: 37 Cases (2008-2015).

To describe patient characteristics of dogs with septic shock, investigate markers of disease severity, and assess treatment impact on outcome. Retrospective study. Single center, university veterinary teaching intensive care unit. Thirty-seven dogs with septic shock. None. Mean number of organ dysfunction was 3.24±1.0, and included cardiovascular (100%), respiratory (73%), hematologic (68%), renal (49%), and hepatic (32%) dysfunction. The gastrointestinal tract was the most common source of sepsis. Mean blood pressure prior to resuscitation was 50±8mm Hg. All dogs were given IV fluids before vasopressor therapy with a mean rate of 12.1±11.0mL/kg/h. All dogs were given antimicrobials, administered within a mean of 4.3±5.7hours after diagnosis. Dopamine or norepinephrine was administered IV, respectively in 51.3% and 37.8% of dogs, with a mean duration of hypotension of 2.6±3.0hours. Mortality rate was 81.1%. Survivors were more likely to have a feeding tube (P=0.007) and to have gastrointestinal sepsis (P=0.012), and less likely to have respiratory dysfunction (P<0.001). APPLEFull scores (P=0.014) and time to antimicrobial therapy (P=0.047) were identified as predictors of mortality. Treatment bundles consisting of 7 interventions that may improve outcomes in people with septic shock were evaluated. Survivors received 4.1±1.3 interventions, whereas nonsurvivors received 2.4±1.4 (P=0.003). Septic shock in dogs confers a guarded prognosis. Early antimicrobial therapy and the utilization of treatment bundles may increase survivability in dogs with septic shock. More research is warranted to investigate the impact of specific interventions on survival.

Protective effects of heparin on early septic shock of intestinal mucosal injury in dogs

Objective Determination of plasma markers of D-lactic acid and I-FABP and analyzed to verify the early septic shock in dogs and intestinal fatty acid binding protein expression levels of D-lactate changes and improvements to septic shock heparin early jejunal villus microcirculation in dogs and intestinal fatty acid binding protein and the expression of D-lactic acid levels, confirmed the protective effect of heparin on intestinal mucosal injury. Methods Beagles early septic shock by intravenous injection of LPS Methods. The 40 animals were randomly random number divided into control group, LPS group, the basic treatment group, heparin group. Stable after 1 hour, i. e. the point T0, to modeling LPS 1 hour, i. e. at T1, after 5 hours was observed sequential T2, T3, T4, T5, T6 point. Observed at the corresponding time points (T1, T3, T6 time points) canine blood collected by 1 500 rpm, 15 minutes after centrifugation, the plasma to the EP tube into aliquots stored at -80 ℃, measured by ELISA intestinal fatty acid binding protein (IFABP) and D-lactate (D-lac). Results heparin group IFABP (21.6±2.3) pg / mL LPS comparison group IFABP (100.48±8.42) pg / mL will be significantly decreased, with statistical significance, P 0.05, on the basis of adequate volume resuscitation on heparin therapy, I-FABP expression levels can be significantly reduced. Conclusions The presence of septic shock early intestinal mucosal microcirculation and intestinal mucosa. Under the premise of its full capacity of recovery, heparin early septic shock in dogs with intestinal mucosal microcirculation improvement, thereby protecting the intestinal mucosal barrier function. Key words: Sepsis / Septic shock; Heparin; Intestinal mucosa; Microcirculation; Lipopolysaccharides; Intestinal binding protein; D-lactic acid; Orthogonal polarization spectral imager

Gentisic acid sodium salt, a phenolic compound, is superior to norepinephrine in reversing cardiovascular collapse, hepatic mitochondrial dysfunction and lactic acidemia in Pseudomonas aeruginosa septic shock in dogs.

BackgroundThe development of lactic acidemia (LA) in septic shock (SS) is associated with an ominous prognosis. We previously showed that the mechanism of LA in SS may relate to impaired hepatic uptake of lactate, but the mechanism was not clear. Uptake of lactate by the liver occurs by a membrane-associated, pH-dependent, antiport system known as the monocarboxylate transporter. In the hepatocyte, lactate can then be metabolized by oxidative phosphorylation or converted to glucose in the cytosol. In the present study, we examined (1) whether hepatic mitochondrial dysfunction accounted for decreased uptake of lactate in a canine model of Pseudomonas aeruginosa SS, (2) whether norepinephrine (NE) treatment by increasing mean arterial pressure (MAP) could improve mitochondrial dysfunction and LA in this model, and (3) whether gentisic acid sodium salt (GSS), a novel phenolic compound, was superior to NE in these effects.MethodsIn anesthetized/ventilated dogs, we infused the bacteria over ~10 h and measured hemodynamics in various treatment groups (see below). We then euthanized the animal and isolated the hepatic mitochondria. We measured hepatic mitochondrial oxygen consumption rates using the novel Seahorse XF24 analyzer under conditions that included: basal respiration, after the addition of adenosine- diphosphate to produce coupled respiration, and after the addition of a protonophore to produce maximal respiration.ResultsWe found that in the septic control group, mean arterial pressure decreased over the course of the study, and that mitochondrial dysfunction developed in which there was a reduction in maximal respiration. Whereas both NE and GSS treatments reversed the reduction in mean arterial pressure and increased maximal respiration to similar extents in respective groups, only in the GSS group was there a reduction in LA.ConclusionsHepatic mitochondrial dysfunction occurs in SS, but does not appear to be required for the development of LA in SS, since NE improved mitochondrial dysfunction without reversing LA. GSS, a phenolic compound restored mean arterial pressure, mitochondrial dysfunction, and LA in SS. This reduction in LA may be independent of its effect on improving hepatic mitochondrial function.Electronic supplementary materialThe online version of this article (doi:10.1186/s40635-016-0095-0) contains supplementary material, which is available to authorized users.

Benefits of ethyl gallate versus norepinephrine in the treatment of cardiovascular collapse in Pseudomonas aeruginosa septic shock in dogs*

Vasopressor therapy is required in septic shock to maintain tissue perfusion in the face of hypotension. Unfortunately, there are significant side effects of current vasopressors, and newer agents need to be developed. We recently discovered that ethyl gallate, a nonflavonoid phenolic antioxidant found in food substances, could reverse low mean arterial pressure found in an experimental model of septic shock due to inhibition of hydrogen peroxide signaling. In the present study, we compared the hemodynamic and biochemical effects of ethyl gallate vs. those of the commonly used vasopressor, norepinephrine, in a bacteremic canine model of Pseudomonas aeruginosa sepsis in two protocols. We performed these studies in anesthetized and mechanically ventilated dogs. In the early treatment protocol, we infused P. aeruginosa until mean arterial pressure first decreased to ∼60 mm Hg (about 2-3 hrs), after which we stopped the infusion and randomly administered ethyl gallate or norepinephrine in respective groups. In the late treatment protocol, we administered ethyl gallate or norepinephrine after a sustained ∼5-hr decrease in mean arterial pressure to 60 mm Hg and continued the infusion for the duration of the experiment. We followed parameters for over 10 hrs after the initiation of P. aeruginosa in both groups. We measured stroke work, urine output, serum creatinine, among other parameters, and used serum troponin T as an index of myocardial injury. We found that in both protocols, ethyl gallate and norepinephrine improved mean arterial pressure and stroke work to similar extents over the duration of the study. Particularly in the late treatment protocol, ethyl gallate resulted in a lower heart rate, a lower troponin T, and a greater urine output as compared with norepinephrine (p < .05). These results suggest that phenolic antioxidants, such as ethyl gallate, that inhibit hydrogen peroxide signaling, may represent an alternative class of vasopressors for use in septic shock.

N,N′-DIACETYLCHITOBIOSE, AN INHIBITOR OF LYSOZYME, REVERSES MYOCARDIAL DEPRESSION AND LESSENS NOREPINEPHRINE REQUIREMENTS IN ESCHERICHIA COLI SEPSIS IN DOGS

Cardiovascular dysfunction in septic shock (SS) is ascribed to the release of inflammatory mediators. Norepinephrine (NE) is often administered to treat low MAP in SS. We recently found that lysozyme c (Lzm-S) released from leukocytes was a mediator of myocardial depression in an Escherichia coil model of SS in dogs. This effect can be blocked in an in vitro preparation by chitobiose, a competitive inhibitor of Lzm-S. In the present study, we examined whether chitobiose treatment can reverse myocardial depression and obviate NE requirements in two respective canine E. coli preparations. In a 6-h study, we administered chitobiose after 3.5 h of E. coli bacteremia and compared stroke work (SW) and MAP at 6 h with a sepsis control group. In a 12-h study, we determined whether chitobiose treatment can reduce the need for NE requirements during 12 h of bacteremia. In the latter study, either chitobiose or NE was given when MAP decreased approximately 20% from the presepsis value in respective groups. In anesthetized, mechanically ventilated dogs, we monitored hemodynamic parameters during continuous E. coli infusion. In the 6-h study, chitobiose improved SW and MAP at the 6-h period as compared with the nontreated sepsis group. In the 12-h study, SW and MAP increased after chitobiose without the necessity of NE administration. These results suggest that inhibitors of Lzm-S such as chitobiose may improve myocardial depression and reduce the need for NE requirements in SS.

Lysozyme binding to endocardial endothelium mediates myocardial depression by the nitric oxide guanosine 3′,5′ monophosphate pathway in sepsis

Inflammatory mediators have been implicated as a cause of reversible myocardial depression in septic shock. We previously reported that the release of lysozyme-c (Lmz-S) from leukocytes from the spleen or other organs contributes to myocardial dysfunction in Escherichia coli septic shock in dogs by binding to a cardiac membrane glycoprotein [J. Mol. Cell. Cardiol. 35 (2003) 265]. However, the mechanism by which Lzm-S causes this depression has not been elucidated. In the present study, we tested the hypothesis that the binding of Lzm-S to a membrane glycoprotein causes myocardial depression by the formation of nitric oxide (NO). NO generation then activates soluble guanylyl cyclase and increases cyclic guanosine monophosphate (cGMP), which in turn triggers contractile impairment via activation of cGMP-dependent protein kinase (PKG). We examined these possibilities in a right ventricular trabecular preparation in which isometric contraction was used to measure cardiac contractility. We found that Lzm-S's depressant effect could be prevented by the non-specific NO synthase (NOS) inhibitor N G-monomethyl- l-arginine ( l-NMMA). A guanylyl cyclase inhibitor (ODQ) and a PKG inhibitor (Rp-8-Br-cGMP) also attenuated Lzm-S's depressant effect as did chemical denudation of the endocardial endothelium (EE) with Triton X-100 (0.5%). In EE tissue, we further showed that Lzm-S caused NO release with use of 4,5 diaminofluorescein, a fluorescent dye that binds to NO. The present study shows that the binding of Lzm-S to EE generates NO, and that NO then activates the myocardial guanosine 3′,5′ monophosphate pathway leading to cardiac depression in sepsis.

Characterization of membrane N-glycan binding sites of lysozyme for cardiac depression in sepsis

In sepsis, reversible myocardial depression has been ascribed to the release of mediators of inflammation. We previously found that lysozyme released from leukocytes from the spleen and other organs mediated myocardial depression in an Escherichia coli model of septic shock in dogs. We hypothesize that lysozyme binds to or cleaves a cardiac surface membrane N-glycoprotein to cause depression. The objectives of the present study were: 1) to determine whether the binding of lysozyme is reversible; 2) to assess the N-glycan structure to which lysozyme binds; 3) to examine whether nonenzymatic proteins, termed lectins, with a binding specificity similar to that of lysozyme could also cause depression; and 4) to assess whether the membrane to which lysozyme binds is affected by the enzymes protease type XIV and collagenase A, that are used to prepare single cell myocyte experiments. We measured isometric contraction in a right ventricular trabecular preparation. We found that lysozyme binds in a reversible manner to the Man beta(1-4) GlcNAc beta(1-4)GlcNAc moiety in the tri-mannosyl core structure of high mannose/hybrid and tri-antennary carbohydrate classes where GlcNAc is N-acetylglucosamine and Man is mannose. Lectins with a specificity similar to that of lysozyme also caused depression, and lysozyme's depressant activity was eliminated by protease type XIV and collagenase A. These results indicate that lysozyme reversibly binds to a membrane glycoprotein to cause myocardial depression in sepsis. We further localize its binding site to a variant of the chitotriose structure in the tri-mannosyl core of the membrane glycoprotein.

Evaluation of hepatosplanchnic circulation and intestinal oxygenation in dogs with a condition that mimicked septic shock induced by continuous infusion of a low dose of lipopolysaccharide

To determine whether continuous infusion of a low dose of lipopolysaccharide (LPS) to induce a condition mimicking septic shock in dogs would affect systemic and hepatosplanchnic circulation and oxygenation. 12 healthy adult Beagles. Dogs received a low dose of LPS (Escherichia coli O55:B5) by continuous IV infusion at a rate of 1 microg/kg/h for 8 hours. Systemic hemodynamics; systemic oxygenation; blood flow in the cranial mesenteric artery, common hepatic artery, and portal vein; intestinal and hepatic tissue blood flow; mesenteric oxygenation; and intramucosal Pco2 were examined before and at selected time points after onset of the LPS infusion. After onset of the LPS infusion, cardiac index increased and mean arterial pressure (MAP) and systemic vascular resistance decreased, which is characteristic of the hyperdynamic state in septic patients. Hepatosplanchnic blood flow increased during the hyperdynamic state. Intestinal Pco2 was increased even when blood flows increased. During the latter half of the experimental period, MAP was maintained but hepatosplanchnic blood flows decreased and intestinal Pco2 increased further. Analysis of the results suggested that hepatosplanchnic blood flow enters the hyperdynamic state during the early stages of sepsis and that intestinal tissue oxygenation is threatened even when hepatosplanchnic blood flow is increased or maintained. Hence, improvement of hepatosplanchnic circulation and intestinal tissue oxygenation is important in dogs with clinical evidence of a septic condition.

Lysozyme: a mediator of myocardial depression and adrenergic dysfunction in septic shock in dogs

The objective of the present study was to identify the nature of a filterable cardiodepressant substance (FCS) that contributes to myocardial dysfunction in a canine model of Escherichia coli septic shock. In a previous study, it was found that FCS increased in plasma after 4 h of bacteremia (Am J Physiol 1993;264:H1402) in which FCS was identified by a bioassay that included a right ventricular trabecular (RVT) preparation. In that study, FCS was only partially identified by pore filtration techniques and was found to be a protein of molecular weight between 10 and 30 K. In the present study, FCS was further purified by size exclusion high-pressure liquid chromatography, until a single band was identified on one-dimensional gel electrophoresis. This band was then subjected to tandem mass spectrometry and protein-sequencing techniques and both techniques identified FCS as lysozyme c (Lzm-S), consistent with that originating from the canine spleen. Confirmatory tests showed that purified Lzm-S produced myocardial depression in the RVT preparation at concentrations achieved during sepsis in the in vivo preparation. In addition, Lzm-S inhibited the adrenergic response induced by field stimulation and the β - agonist isoproterenol in in vitro preparations, these results suggesting that Lzm-S may inhibit the sympathetic response in sepsis. The present findings indicate that Lzm-S originating from disintegrating leukocytes from organs such as the spleen contributes to myocardial dysfunction in this model. The mechanism may relate to its binding or hydrolysis of a cardiac membrane glycoprotein thereby interfering with myocardial excitation–contraction coupling in sepsis.

Blood pH level modulates organ metabolism of lactate in septic shock in dogs

Objective: Lactic acidosis is an important complication of septic shock. Alkali treatment such as sodium bicarbonate is often used to treat the low pH level that develops in sepsis. The effect of this treatment on lactate (Lac) clearance is not clear. In the present study, the objective was to examine whether blood pH level alters Lac metabolism in sepsis. Measurements were determined in a canine model of Escherichia coli sepsis after bolus infusion (5 mmol/kg) of either lactic acid (LA) or sodium lactate (NaL). In one preparation, Lac uptake by the splanchnic organs (SP), liver, lung, kidneys (Kid), and soft tissues of the lower extremity (SOL) was primarily determined, whereas in another preparation, Lac uptake by the head and neck region and lung was obtained. Methods: The dogs were studied while anesthetized and ventilated. After 4 hours of sepsis, either LA or NaL was given through a catheter positioned in the abdominal aorta in respective sepsis (SepLA, SepNaL) and nonsepsis groups (ConLA, ConNaL) (n ≈ 6 in each preparation). Catheters and flow probes were used to measure organ Lac uptake. Measurements were obtained at end infusion and at 15-minute intervals after infusion until 75 minutes after infusion. Results: Arterial clearance of Lac in the sepsis groups was slower as compared with the nonsepsis groups. In the liver, sepsis inhibited the uptake of LA as compared with the nonseptic group. In SP, both sepsis and pH affected Lac uptake in which an increase in uptake was found only after NaL infusion in the nonseptic group. In the head and neck region, Lac uptake was pH-level dependent and was found after LA infusion in the sepsis and nonsepsis groups. In the lung, Lac was produced after either LA or NaL infusion in all groups. Neither Kid nor SOL contributed to Lac uptake in any of the groups. Conclusion: Lactate clearance was reduced in sepsis. Both effects of pH level and sepsis modulated the organ uptake of Lac in septic shock. Only a small amount of the total Lac infused could be accounted for by the organs measured in the present study. This suggests that additional organs may account for lactate removal in sepsis. Copyright 2002, Elsevier Science (USA). All rights reserved.

Intravenous administration of hypertonic sodium chloride solution with dextran or isotonic sodium chloride solution for treatment of septic shock secondary to pyometra in dogs

Objective To determine effects of IV administration of hypertonic saline (7.5% NaCl) solution with 6% dextran 70 (HSSD) or isotonic saline (0.9% NaCl) solution (ISS) to dogs with septic shock secondary to pyometra. Design Prospective, randomized, clinical study. Animals 14 client-owned dogs with septic shock secondary to pyometra. Procedure Prior to emergency ovariohysterectomy, catheters were placed in pulmonary and femoral arteries of each dog to evaluate hemodynamic and oxygenation status. Immediately prior to surgery, 7 dogs received HSSD (4 ml/kg [1.82 ml/lb] of body weight, IV) and 7 dogs received ISS (32 ml/kg [14.54 ml/lb], IV) during a 5-minute period. Measurements of hemodynamic and oxygenation variables were obtained before and 5 and 20 minutes after administration of fluids. Results Mean arterial pressure (MAP) increased significantly 5 and 20 minutes after administration of HSSD, whereas ISS did not affect MAP. However, cardiac output, cardiac index, and oxygen delivery increased and hematocrit decreased after both treatments. Oxygen consumption and extraction rate and degree of acidosis did not improve after either treatment. Conclusions and Clinical Relevance Intravenous administration of small volumes of HSSD to dogs with septic shock secondary to pyometra resulted in improvement of hemodynamic and oxygenation status. Although cardiac output, cardiac index, and oxygen delivery improved after administration of a volume of ISS equal to 8 times that of HSSD, MAP increased to &gt; 80 mm Hg only after treatment with HSSD. Administration of HSSD may be an effective treatment for septic shock in dogs. (J Am Vet Med Assoc 1999;215:1283–1287)

Anatomic arterial-venous shunting in endotoxic and septic shock in dogs.

Shunting of radionuclide labeled 9 micron diameter microspheres by the systemic circulation, and 6 body regions was measured in two dog shock models: endotoxic shock (1 mg/kg E. Coli endotoxin intravenously) and sepsis and septic shock (5 days after cecal ligation). Mean systemic arterial blood pressure was significantly lower than control in both the endotoxic and septic shock groups. Mean systemic shunting was 7.7% in the control group and 7.3% and 4.3% respectively in the endotoxic and septic shock groups. Regional shunting of the head, heart, and skeletal muscle were not significantly different in the three groups. However, mean shunting in the splanchnic circulation was 36.5% in the septic shock group as compared to 18.6% in the control group (p less than 0.05). Mean kidney shunting in the endotoxic group was 15.1% compared to 4% in the control group (p less than 0.05). During resuscitation with crystalloid, mannitol, blood, and cortiocosteroids mean aterial blood pressure and cardiac index increased but systemic arterial-venous shunting was 3.8 and 4.3% in endotoxic and septic shock respectively. These data show that systemic anatomic arterial-venous shunting is small and not different from control in both dog shock models, and regional arterial-venous shunting is increased only in the splanchnic circulation in the septic model and in the kidney in the endotoxin model.