Increased Lactate Concentrations in III and Injured Dogs

Venous blood lactate concentrations were measured on 109 ill dogs and 20 clinically normal dogs. Ill dogs were grouped into survivor and nonsurvivor groups, and categorized based on their primary problem. Ninety-five percent of ill dogs had lactate concentrations higher than clinically normal dogs and published normal values. Seventy-six percent of ill dogs with increased lactate concentrations survived to be discharged. Lactate concentrations were significantly higher in nonsurvivors than in survivors and clinically normal dogs. Lactate concentrations in dogs with major trauma and intoxications, and with cardiopulmonary, gastrointestinal, and neurologic problems were significantly higher than in clinically normal dogs and dogs with other problems. (Vet Emerg & Crit Care, 1998; 8: 117–127)     

Lactate: physiology and clinical utility

Objective: To review the physiology of lactate production and metabolism, the causes of lactic acidosis, and the current applications of lactate monitoring in humans and animals. Data sources: Human and veterinary studies. Summary: Lactate production is the result of anaerobic metabolism. Tissue hypoxia due to hypoperfusion is the most common cause of lactic acidosis. Studies in critically ill humans have shown that serial lactate monitoring can be used to assess the severity of illness and response to therapy. Several veterinary studies have also shown lactate as a useful tool to assess severity of illness. Conclusions: Lactate measurement in critically ill veterinary patients is practical and can provide information to assess severity of illness. Further veterinary studies are needed to establish the value of serial lactate measurements for prognostic and therapeutic purposes. Information regarding lactate measurement in cats is limited, and further studies are warranted.     

Retrospective evaluation of the prognostic utility of plasma lactate concentration,base deficit,pH, and anion gap in canine and feline emergency patients

Objective

To determine the association of plasma lactate concentration, pH, base deficit (BD), and anion gap (AG) in dogs and cats on presentation to an emergency room with outcome, and to compare the prognostic significance of hyperlactatemia with a concurrent metabolic acidosis with that of hyperlactatemia and a normal metabolic acid–base balance.

Design

Retrospective study.

Setting

University teaching hospital.

Animals

Five hundred sixty‐six dogs and 185 cats that had venous blood gas analysis performed.

Interventions

None.

Measurements and Main Results

Medical records were reviewed for plasma lactate concentrations, electrolyte concentrations, and acid–base parameters obtained on emergency room admission, clinical diagnosis, and in‐hospital mortality. The primary outcome measure was all‐cause mortality for the hospitalized visit. Median plasma lactate concentration and AG were higher, BD was more negative, and pH was lower, in non‐survivor dogs and cats. The prevalence of hyperlactatemia was 53% in dogs and 30% in cats. Lactic acidosis was present in 42% and 80% of hyperlactatemic dogs and cats, respectively. Multivariate regression analyses revealed that plasma lactate concentration, BD, and pH, but not AG, were independent predictors of mortality in dogs, and that only plasma lactate concentration was an independent predictor of mortality in cats. Mortality was highest for animals with lactic acidosis, at 59.8% in dogs and 49% in cats. Mortality in dogs with lactic acidosis was significantly higher than dogs with hyperlactatemia and a normal acid–base status (P < 0.0001).

Conclusions

The presence and magnitude of hyperlactatemia on presentation to the emergency room may help identify dogs and cats with high likelihood of in‐hospital mortality, and the presence of lactic acidosis specifically may help identify dogs with yet higher risk of in‐hospital mortality.     

Pilot study of oral metformin in cancer‐bearing cats

A prospective dose escalation pilot study was performed in cancer‐bearing cats to assess toxicity and surrogate biomarkers of pharmacologic activity of oral metformin hydrochloride. Nine cats with measurable spontaneous cancer were treated with oral metformin for 14 days. Monitoring included complete blood count (CBC), serum biochemistry, lactate, pH, insulin‐like growth factor‐1, and vascular endothelial growth factor serially until study completion. At the maximum tolerated dose of 10 mg kg^?1 q12 h side effects were primarily mild to moderate gastrointestinal upset (anorexia, vomiting, and/or weight loss). All cats developed a reduction in haematocrit. Six of nine cats developed new or progressive hyperlactatemia and one cat developed asymptomatic lactic acidosis. There were no clinical responders and two cats had modest measurable reduction in tumour size. In conclusion, we demonstrate potential pharmacologic activity of metformin at a clinically relevant dose and identify parameters for clinical monitoring and supportive care. Further investigation of metformin in cancer‐bearing cats is warranted.     

Neuromuscular Blocking Drugs and the Critical Care Patient

As the management of critically ill and emergency patients intensifies and veterinary surgical procedures become more complex, more sophisticated methods of support are becoming necessary. Emergency and critical care patients are excellent candidates for the use of neuromuscular blocking drugs. The main advantage of the current generation of neuromuscular blocking drugs compared to earlier agents is that they provide muscle relaxation with little or no cardiovascular effects. The pharmacology and physiology of neuromuscular blocking drugs are discussed, and their use is described with specific references to critical care patients. Monitoring techniques are described and reversal of neuromuscular blockade as well as potential side effects and adverse reactions arediscussed.     

毛茛科植物提取物添加量对瘤胃微生物体外动态发酵的影响

试验采用活体外产气量法研究毛茛科植物提取物不同添加水平对瘤胃微生物体外发酵的影响。试验采用单因子完全随机化试验设计,以小麦面粉为底物进行体外发酵。瘤胃液供体动物为3头装有永久性瘤胃瘘管的本地黄牛,日粮精料水平为30%(日饲喂2次)。植物提取物添加水平分别为0、100、200、300和400mg/L。结果表明:随着毛茛科植物提取物添加水平的提高,小麦面粉24h的DM消化率呈线性下降(P=0.0002),活体外产气速度呈二次曲线规律降低(P=0.0001),而产气延滞期线性增加(P=0.0001),理论最大产气量呈二次曲线规律增加(P=0.0001)。随着植物提取物添加水平的提高,发酵液pH值呈二次曲线增加(P<0.024)。各培养时间点乳酸含量均较低(P<1mmol/L),且各处理之间差异不显著(P>0.10)。提高植物提取物添加水平导致tVFA产量呈二次曲线趋势下降(P<0.01)。通过本试验可得出:毛茛科植物提取物可以通过降低瘤胃发酵的产气速度、提高发酵液pH值以及乙酸和丁酸摩尔比例来调控瘤胃微生物体外发酵,其中植物提取物的适宜添加水平为200～300mg/L。     

Evaluation of a portable lactate analyzer (Lactate Scout) in dogs

BACKGROUND: Measurement of blood lactate concentration has become a common practice in canine medicine. However, the accuracy of portable lactate monitors has not been reported in dogs. OBJECTIVES: The aim of this study was to evaluate the accuracy and precision of a portable analyzer (Lactate-Scout) in measuring canine blood lactate concentration. METHODS: A preliminary study was performed to assess the effects of sample storage time and temperature on plasma lactate concentration. Blood samples obtained from 6 canine patients at our hospital were divided into 8 aliquots and stored at 4 degrees C and 20 degrees C; plasma lactate was measured in duplicate with a spectrophotometric system (Konelab) at 0, 30, 60, 120, and 240 minutes after the blood collection. Values were compared with those obtained immediately after blood collection. Lactate values obtained by the portable method also were compared with those obtained by the reference spectrophotometric analyzer on blood samples collected from 48 additional canine patients. RESULTS: There was no significant effect of storage time (P = .89) or temperature (P = .51) on plasma lactate levels. The correlation between lactate values measured with the Lactate-Scout and the Konelab method was r = .98 (slope = .81, 95% confidence interval = .73-.87; intercept = .20, 95% confidence interval = .13-.31). The level of agreement between the 2 methods was generally good for mean lactate concentrations <5 mmol/L. However, at higher lactate concentrations (5 of 48 samples), the values recorded by the Lactate-Scout analyzer were lower than those measured by the Konelab method. CONCLUSION: The Lactate-Scout analyzer is reliably comparable to a reference method for measuring whole blood lactate concentration in dogs; however, caution should be used when interpreting lactate values of 5 mmol/L and higher.     

The use of intravenous lipid emulsion as an antidote in veterinary toxicology

Objective – To review the use of IV lipid emulsion (ILE) for the treatment of toxicities related to fat‐soluble agents; evaluate current human and veterinary literature; and to provide proposed guidelines for the use of this emerging therapy in veterinary medicine and toxicology. Data Sources – Human and veterinary medical literature. Human Data Synthesis – Human data are composed mostly of case reports describing the response to treatment with ILE as variant from mild improvement to complete resolution of clinical signs, which is suspected to be due to the variability of lipid solubility of the drugs. The use of ILE therapy has been advocated as an antidote in cases of local anesthetic and other lipophilic drug toxicoses, particularly in the face of cardiopulmonary arrest and unsuccessful cardiopulmonary cerebral resuscitation. Veterinary Data Synthesis – The use of ILE therapy in veterinary medicine has recently been advocated by animal poison control centers for toxicoses associated with fat‐soluble agents, but there are only few clinical reports documenting successful use of this therapy. Evidence for the use of ILE in both human and veterinary medicine is composed primarily from experimental animal data. Conclusions – The use of ILE appears to be a safe therapy for the poisoned animal patient, but is warranted only with certain toxicoses. Adverse events associated with ILE in veterinary medicine are rare and anecdotal. Standard resuscitation protocols should be exhausted before considering this therapy and the potential side effects should be evaluated before administration of ILE as a potential antidote in cases of lipophilic drug toxicoses. Further research is waranted.