Update: Clinical Use of Plasma Lactate

SERIAL CHANGES IN METABOLIC ACID-BASE STATUS IN THREE SPECIES OF ANESTHETIZED CAPTIVE LARGE FELID

Determination of acid-base status contributes important information about patient health, including for patients under anesthesia. There is a paucity of information about the determinants of acid-base status of large felids managed under anesthesia, and advancement of such knowledge may contribute to patient safety. This study serially monitored the individual metabolic acid-base status of 11 large felids, including lions (Panthera leo), tigers (Panthera tigris), and cheetahs (Acinonyx jubatus), under general anesthesia. We analyzed the contributions of measured strong ions (sodium, chloride, potassium, lactate), weak acids and buffers (albumin, phosphate and bicarbonate), and unmeasured anions to standardized extracellular base excess (SBE). A general linear model assessed for species differences in these parameters, with time since immobilization, SBE, and mean arterial pressure as covariates. By employing a Stewart-based analytical approach, it was possible to separate chloremic and unmeasured anion contributions to metabolic acid base status. This provided a basis for identifying mixed metabolic processes, generating differentials for underlying causes. Using normal acid base parameters for domestic felids, metabolic acidosis was found to be prevalent. Frequent evidence of unmeasured anion accumulation was also found, with unmeasured anions occasionally exceeding 5mmol/L. These findings warrant further inquiry into the drivers and clinical significance of metabolic acidosis and unmeasured anion accumulations in anesthetized large felids, encouraging further anion identity studies to elucidate possible causes. Reference ranges need to be established for acid-base parameters in large felids as a foundation for interpreting more controlled, prospective research into determinants of metabolic acid-base status in these animals under anesthesia.

A comparison of the Sepsis-2 and Sepsis-3 definitions for assessment of mortality risk in dogs with parvovirus

OBJECTIVE

To evaluate the use of a modified Sepsis-3 (mSepsis-3) definition compared to the currently used modified Sepsis-2 (mSepsis-2) definition to determine whether the mSepsis-2 or mSepsis-3 stratifications were able to identify populations of dogs ultimately more likely to die from canine parvovirus (CPV) infection.

DESIGN

Retrospective, January 2009 to March 2020.

SETTING

A private, small animal, urban, referral emergency and specialty hospital.

ANIMALS

Fifty-nine client-owned dogs hospitalized for treatment of CPV.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Dogs were divided into mSepsis-2 and mSepsis-3 categories based on the highest level of illness severity reached during hospitalization. Greater illness severity based on mSepsis-2 criteria (ie, sepsis, severe sepsis, septic shock) was associated with an increase in average length of stay (P < 0.001), increase in average cost of stay (P < 0.01), and presence of leukopenia (P < 0.05). An increase in illness severity within the mSepsis-2 criteria was not associated with hyperlactatemia (P = 0.29), presence of neutropenia (P = 0.12), or mortality (P = 0.35). Greater illness severity based on mSepsis-3 criteria (ie, infection only, sepsis, septic shock) was associated with an increase in mortality (P < 0.05), increase in average length of stay (P < 0.001), increase in average cost of stay (P < 0.01), presence of leukopenia (P < 0.01), and presence of neutropenia (P < 0.05). The mSepsis-3 criteria were not associated with the presence of hyperlactatemia (P = 0.68). There was no significant difference between survivors and nonsurvivors in the presence of leukopenia (P = 0.19), neutropenia (P = 0.67), or hyperlactatemia (P = 0.58).

CONCLUSIONS

The mSepsis-3 diagnostic criteria appear to better identify dogs with CPV at higher risk for mortality compared to the mSepsis-2 criteria.

Influence of acetate- vs. lactate-containing fluid bolus therapy on acid-base status, electrolytes, and plasma lactate in dogs

Objective

Acetate- and lactate-containing fluids influence the acid-base and electrolyte status. This prospective, randomized, clinical study compared two balanced crystalloid solutions regarding their influence on acid-base status, electrolytes, and lactate values, when given to dogs as a resuscitation bolus of 30 mL/kg.

Material and methods

One hundred client-owned dogs presenting to the emergency service with signs of fluid deficits were randomly assigned to receive an intravenous bolus of 30 mL/kg of either a lactate- (LAC), or an acetate-containing solution (ACET). Before and after the bolus, vital parameters were assessed, and a venous blood gas analysis was performed.

Results

Both solutions performed equally well in decreasing the heart rate (ACET: −10 ± 27 bpm, LAC: −12 ± 30 bpm; p = 0.737). The acetate-containing solution caused a significant decrease in plasma lactate levels (p = 0.016), anion gap (p &lt; 0.001), and potassium (p &lt; 0.001), and a significant increase in chloride (p &lt; 0.001), and ionized calcium (p = 0.014). The lactate-containing solution caused a significant decrease in anion gap (p &lt; 0.001), sodium (p = 0.016), and potassium (p = 0.001), and a significant increase in chloride (p &lt; 0.001). ACET causes a stronger decrease in plasma lactate (p = 0.015), sodium (p = 0.039), potassium (p = 0.006), and an increase in chloride (p &lt; 0.001), and ionized calcium (p = 0.016) compared to LAC.

Conclusion

Both solutions caused mild changes in electrolyte concentrations and had minor influence on acid-base status when used for bolus therapy in dogs with fluid deficits. Further studies are needed to evaluate their influence on acid-base status, lactate, and electrolytes when used in larger volumes and for a longer time span.

Orthopedic Surgery Causes Gut Microbiome Dysbiosis and Intestinal Barrier Dysfunction in Prodromal Alzheimer's Disease Patients: A Prospective Observational Cohort Study

Objective:

To investigate gut microbiota and intestinal barrier function changes after orthopedic surgery in elderly patients with either normal cognition (NC) or a prodromal Alzheimer disease phenotype (pAD) comprising either subjective cognitive decline (SCD) or amnestic mild cognitive impairment (aMCI).

Background:

Homeostatic disturbances induced by surgical trauma and/or stress can potentially alter the gut microbiota and intestinal barrier function in elderly patients before and after orthopedic surgery.

Methods:

In this prospective cohort study, 135 patients were subject to preoperative neuropsychological assessment and then classified into: NC (n=40), SCD (n=58), or aMCI (n=37). Their gut microbiota, bacterial endotoxin (lipopolysaccharide), tight junction (TJ) protein, and inflammatory cytokines in blood were measured before surgery and on postsurgical day 1, 3, and 7 (or before discharge).

Results:

The short-chain fatty acid (SCFA)-producing bacteria were lower while the gram-negative bacteria, lipopolysaccharide and TJ were higher preoperatively in both the SCD and aMCI (pAD) groups compared with the NC group. After surgery, a decrease in SCFA-producing bacteria, and an increase in both gram-negative bacteria and plasma claudin were significant in the pAD groups relative to the NC group. SCFA-producing bacteria were negatively correlated with TJ and cytokines in pAD patients on postsurgical day 7. Furthermore, surgery-induced perioperative metabolic stress and inflammatory responses were associated with gut microbiota alterations.

Conclusions:

Surgery exacerbates both preexisting microbiota dysbiosis and intestinal barrier dysfunction in pAD patients, all of which may be associated with systemic inflammation and, in turn, may lead to further cognitive deterioration.

Are Baseline Levels of Gas6 and Soluble Mer Predictors of Mortality and Organ Damage in Patients with Sepsis? The Need-Speed Trial Database

Soluble tyrosine kinase receptor Mer (sMer) and its ligand Growth arrest-specific protein 6 (Gas6) are predictors of mortality in patients with sepsis. Our aim is to clarify whether their measurement at emergency department (ED) presentation is useful in risk stratification. We re-analyzed data from the Need-Speed trial, evaluating mortality and the presence of organ damage according to baseline levels of sMer and Gas6. 890 patients were eligible; no association with 7- and 30-day mortality was observed for both biomarkers (p > 0.05). sMer and Gas6 levels were significantly higher in acute kidney injury (AKI) patients compared to non-AKI ones (9.8 [4.1–17.8] vs. 7.9 [3.8–12.9] ng/mL and 34.8 [26.4–47.5] vs. 29.8 [22.1–41.6] ng/mL, respectively, for sMer and Gas6), and Gas6 also emerged as an independent AKI predictor (odds ratio (OR) 1.01 [1.00–1.02]). Both sMer and Gas6 independently predicted thrombocytopenia in sepsis patients not treated with anticoagulants (OR 1.01 [1.00–1.02] and 1.04 [1.02–1.06], respectively). Moreover, sMer was an independent predictor of both prothrombin time-international normalized ratio (PT-INR) > 1.4 (OR 1.03 [1.00–1.05]) and sepsis-induced coagulopathy (SIC) (OR 1.05 [1.02–1.07]). An early measurement of the sMer and Gas6 plasma concentration could not predict mortality. However, the biomarkers were associated with AKI, thrombocytopenia, PT-INR derangement and SIC, suggesting a role in predicting sepsis-related organ damage.

Influence of acetate containing fluid versus lactate containing fluid on acid-base status, electrolyte level, and blood lactate level in dehydrated dogs

BACKGROUND AND AIM

Acetate or lactate buffered, balanced isotonic rehydration fluids are commonly used for fluid therapy in dogs and may influence acid-base and electrolyte status. This study aimed to assess acid-base status, electrolyte levels, and lactate levels in dehydrated dogs after receiving acetate or lactate-containing intravenous rehydration fluids.

MATERIALS AND METHODS

In this prospective, randomized study, 90 dehydrated dogs were included and randomized to receive acetate [Sterofundin® ISO B. Braun Vet Care (STERO), Germany) or lactate (Ringer-Lactat-Lösung nach Hartmann B. Braun Vet Care (RL), Germany] containing intravenous fluids for rehydration. The exclusion criteria were as follows: Age <6 months, liver failure, congestive heart failure, and extreme electrolyte deviation. Physical examination, venous blood gas, and lactate levels were analyzed before and after rehydration. The two groups were compared using t-test and Chi-square test. The significance level was set at p≤0.05.

RESULTS

Post-rehydration heart rate decreased in the STERO group (p<0.001) but not in the RL group (p=0.090). Lactate levels decreased in both groups STERO (p<0.001) and in group RL (p=0.014). Sodium and chloride levels increased during rehydration in group STERO (p<0.001; p<0.001) and group RL (p=0.002; p<0.001). There was a larger decrease in lactate levels in group STERO compared to group RL (p=0.047).

CONCLUSION

Both solutions led to a mild increase in sodium and chloride levels and decreased lactate levels. The acetate-containing solution had an inferior effect on the decrease in lactate level.

Perioperative Outcome in Dogs Undergoing Emergency Abdominal Surgery: A Retrospective Study on 82 Cases (2018-2020)

Emergency abdominal surgery carries high morbidity and mortality rates in human medicine; however, there is less evidence characterising the outcome of these surgeries as a single group in dogs. The aim of the study was to characterise the clinical course, associated complications and outcome of dogs undergoing emergency abdominal surgery. A retrospective study was conducted. Dogs undergoing emergency laparotomy were included in the study. Logistic regression analysis was performed to identify variables correlated with death and complications. Eighty-two dogs were included in the study. The most common reason for surgery was a gastrointestinal foreign body. Overall, the 15-day mortality rate was 20.7% (17/82). The median (range) length of hospitalisation was 3 (0.5-15) days. Of the 82 patients, 24 (29.3%) developed major complications and 66 (80.5%) developed minor complications. Perioperative factors significantly associated with death included tachycardia (p < 0.001), hypothermia (p < 0.001), lactate acidosis (p < 0.001), shock index > 1 (p < 0.001), leukopenia (p < 0.001) and thrombocytopenia (p < 0.001) at admission, as well as intraoperative hypotension (p < 0.001) and perioperative use of blood products (p < 0.001). The results of this study suggest that mortality and morbidity rates after emergency abdominal surgery in dogs are high.

Analysis of Early Assessable Risk Factors for Poor Outcome in Dogs With Cluster Seizures and Status Epilepticus

Status epileptics (SE) and cluster seizures (CS) are serious neurological emergencies associated with poor outcome in epileptic patients. Data on risk factors associated with outcome in epileptic patients affected by CS and SE have not been studied extensively to date. In the present retrospective study potential risk factors predictive of negative outcome in a population of dogs affected by CS and SE were analyzed. Ninety-three dogs were included in the study: 21/93 patients (23%) presented with SE and 72/93 (77%) with CS. Based on multivariate statistical analysis, factors statistically associated with a poor outcome were the occurrence of the first epileptic seizure outside the defined idiopathic interval (6 months-6 years), a condition of hyperthermia at presentation and the absence of previous antiepileptic drugs (AEDs) in case of previous history of seizures. The results of the present study implement data on risk factors associated with poor outcome in dogs affected by CS or SE and can aid in the creation of an ad hoc scoring system, similar to systems currently applied in human medicine upon hospital admission to benchmark performances and establish protocols for triage and therapeutic management.

Evaluation of subcutaneously administered electrolyte solutions in experimentally dehydrated inland bearded dragons (Pogona vitticeps)

OBJECTIVE

To evaluate the effects of 3 electrolyte solutions administered SC to experimentally dehydrated inland bearded dragons (Pogona vitticeps).

ANIMALS

9 inland bearded dragons.

PROCEDURES

In a randomized, complete crossover study, experimental dehydration was induced by means of furosemide (10 mg/kg, SC, q 12 h for 4 doses), and then lactated Ringer solution, Plasma-Lyte A, or reptile Ringer solution (RRS; 1:1 mixture of 5% dextrose solution and isotonic crystalloid solution) was administered SC in a single 50-mL/kg dose in 3 treatments sessions separated by a minimum of 14 days. Food and water were withheld during treatment sessions. Plasma biochemical values, PCV, blood total solids and lactate concentrations, and plasma osmolarity were measured prior to (baseline) and 4 and 24 hours after fluid administration.

RESULTS

Administration of RRS resulted in severe hyperglycemia (mean ± SD plasma glucose concentration, 420 ± 62 mg/dL), compared with baseline values (190 ± 32 mg/dL), and this hyperglycemia persisted for at least 24 hours. It also resulted in significant reductions in plasma osmolarity and sodium and phosphorus concentrations, which were not observed after administration of the other 2 solutions. Administration of lactated Ringer solution caused no significant increase in blood lactate concentration.

CONCLUSIONS AND CLINICAL RELEVANCE

The changes in plasma glucose, sodium, and phosphorus concentrations and plasma osmolarity observed after SC administration of a single dose of RRS suggested this type of electrolyte solution should not be used for rehydration of bearded dragons. Rather, lactated Ringer solution or Plasma-Lyte A should be considered instead.

Evaluation of hematologic, biochemical, and blood gas variables in stored canine packed red blood cells, and the impact of storage time on blood recipients

BACKGROUND

Canine packed red blood cells (pRBCs) can be stored under refrigeration for several days; however, cellular metabolism remains active inside the units, thus producing substances that affect their quality.

OBJECTIVES

We aimed to evaluate hematologic, biochemical, and blood gas variable alterations that occur in canine pRBCs during storage, and their effects on recipient clinicopathologic parameters.

METHODS

The study was conducted in two phases. In phase I, 15 pRBC units containing CPDA-1 were stored for 28 days; samples were collected weekly from the units of days 0 to 28 to measure the packed cell volume (PCV), pH, partial pressure carbon dioxide (PCO₂ ), partial pressure oxygen (PO₂ ), concentrations of lactate and potassium, and the percent hemolysis. In phase II, another 22 canine pRBC units stored for different time periods (maximum of 21 days) were transfused, and the recipients were evaluated before and after transfusion for changes in clinical parameters (heart rate, respiratory rate, systolic arterial pressure, and rectal temperature) and hematologic variables (PCV, lactate and potassium concentrations, pH, PCO₂ , the ratio of arterial oxygen partial pressure to fractional inspired oxygen [PO₂ /FiO₂ ] ratio, oxygen saturation [SaO₂ ], base excess, and bicarbonate [HCO₃ ]).

RESULTS

In the pRBC units, the PCV increased from 70% to 78.33%, the lactate concentration increased 627%, the potassium concentration increased 183%, the percent hemolysis reached 0.69%, and the pH decreased 9% after 28 days. However, the dogs who received transfusions were not negatively affected. There was a significant increase in PCVs, and a significant decrease in heart rates.

CONCLUSION

Canine pRBCs undergo hematologic, blood gas, and biochemical alterations during storage; however, the transfusion of pRBCs stored for up to 21 days increased PCVs without causing harm to the dogs.

Retrospective evaluation of the association between admission blood glucose and l-lactate concentrations in ponies and horses with gastrointestinal disease (2008-2016): 545 cases

OBJECTIVES

A recent study described increased l-lactate concentrations in ponies with gastrointestinal disease compared to horses, but blood glucose (BG) concentrations were not considered. The study tested the hypothesis that BG and l-lactate concentrations are correlated in horses and ponies with gastrointestinal disease and that BG concentrations, not equid type (pony vs horse), are an independent predictor of L-lactate concentrations. It was further hypothesized that equid type was an independent predictor of BG concentrations.

DESIGN

Retrospective study 2008-2016.

SETTING

University teaching hospital.

ANIMALS

Admission data from 545 animals (384 horses and 161 ponies) with gastrointestinal disease.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Data collected included signalment, clinicopathological findings on admission, and nature and location of the gastrointestinal lesion (strangulating vs non-strangulating and large vs small intestinal lesion). The association between admission blood l-lactate concentrations, equid type (pony or horse) and BG concentrations was investigated in a multivariable model. Admission l-lactate and BG concentrations were strongly correlated (n = 522; r = 0.63; P < 0.001). Ponies had significantly higher l-lactate (2.7 mmol/L (0.5-18.0 mmol/L) vs 1.4 mmol/L (0.3-19 mmol/L); P < 0.001) and BG concentrations than horses (8.4 mmol/L (4.2-24.4 mmol/L); 151 mg/dL (76-439 mg/dL) vs 6.9 mmol/L (3.4-26.8 mmol/L); 124 mg/dL (61-482 mg/dL); P < 0.001). In the multivariable analysis, l-lactate concentrations were significantly and positively associated with admission BG concentrations in all animals and also with equid type. For each millimole per liter (18 mg/dL) increase in BG, l-lactate concentrations increased by 7.9% (5.9, 9.9); P < 0.001. In comparison to ponies, l-lactate concentrations were decreased by 27.7% (37.4, 16.5); P < 0.001 in horses. Admission BG concentrations were significantly and positively associated with l-lactate concentrations in all animals. For each millimole per liter increase in l-lactate concentration, BG concentration increased by 6.2% (4.7, 7.6; P < 0.001). Admission BG concentrations were not associated with equid type.

CONCLUSION

Admission BG concentrations and equid type are independent predictors of blood l-lactate concentrations in equids with gastrointestinal disease, but their relationship requires further investigation.

Health status assessment of traumatic injury freshwater turtles

A group of injured yellow-bellied sliders (Trachemys scripta) and river cooters (Pseudemys concinna) were evaluated for a variety of health values at presentation to the NC State Turtle Rescue Team and prior to release. An i-STAT Portable Clinical Analyzer and CG8+ cartridges were used to determine venous blood gas and biochemical values, the packed cell volume (PCV) and total protein were evaluated using hematocrit tubes and high speed centrifugation, and a differential WBC percentage was determined manually with Diff-Quick stained blood smear slides. Forty-six turtles were sampled on presentation and twenty-three of those were sampled again prior to release. Blood values were analyzed for significant differences between samples collected at presentation and prior to release, as well as differences between surviving and non-surviving turtles. Five variables were identified as significantly different between presenting and recuperated samples: pH, pCO2, Glu, % heterophils, and % eosinophils. When comparing samples between turtles that survived versus those that did not, two variables were identified as being significant prognostic indicators; lactate and PCV. Identification of these significant variables can aid in determining patient prognosis and triage therapy for injured aquatic turtles.