高钾血症模型的建立及抢救措施机理的分析

高钾血症是临床上多种疾病所并发的一种常见病理生理过程。血钾升高的最大危害是心肌毒性,它可引起机体心律失常甚至心脏停搏危及生命。因此,预防高钾血症的发生和采取有效的处理方法,一直是病理生理学研究的热点问题之一。了解高血钾对心肌细胞的毒性作用及寻找抢救方法。制备高血钾家兔模型,并分别用葡萄糖酸钙、NaHCO3进行抢救。高钾血症时,心电图可见家兔心律失常,并且T波高耸,Q—T间期缩短,同时,还会使机体的呼吸系统发生变化;用葡萄糖酸钙、NaHCO3后,抢救成功。高血钾对心脏有毒性作用,浓度升高速度越快,毒性作用越大。静脉推注高葡萄糖溶液、NaHCO3溶液都对缓解高血钾症有一定的作用;心电图可作为诊断高血钾,判定其程度和观察疗效的重要指标。     

Cortisol Concentrations in Well‐Regulated Dogs with Hyperadrenocorticism Treated with Trilostane

Background

There are no clear treatment guidelines for dogs with clinically well‐regulated hyperadrenocorticism in which serum cortisol concentrations before and after an ACTH stimulation test performed 3–6 hours after trilostane administration are < 2.0 μg/dL.

Objective

To determine if serum cortisol concentrations measured before (Pre1) and after (Post1) ACTH stimulation at 3–6 hours after trilostane administration are significantly lower than cortisol concentrations measured before (Pre2) and after (Post2) ACTH stimulation 9–12 hours after trilostane administration, in a specific population of dogs with clinically well‐regulated hyperadrenocorticism and Pre1 and Post1 <2 μg/dL.

Animals

Thirteen client‐owned dogs with clinically well‐regulated hyperadrenocorticism and Pre1 and Post1 serum cortisol concentrations <2.0 μg/dL 3–6 hours after trilostane administration.

Methods

Prospective study. Dogs had a second ACTH stimulation test performed 9–12 hours after trilostane administration, on the same day of the first ACTH stimulation test. Cortisol concentrations before and after ACTH stimulation were compared using a paired t‐test.

Results

Cortisol concentrations before (1.4 ± 0.3 μg/dL) and after the first stimulation (1.5 ± 0.3 μg/dL, mean ± SD) were significantly lower than cortisol concentration before the second stimulation (3.3 ± 1.6 μg/dL, P = .0012 each). Cortisol concentration before the first stimulation was also significantly lower than cortisol concentration after the second stimulation (5.3 ± 2.4 μg/dL, P = .0001).

Conclusions and clinical importance

In dogs with clinically well‐regulated, trilostane‐treated, hyperadrenocorticism, and cortisol concentrations <2 μg/dL before and after the first stimulation, a second ACTH stimulation test performed 9–12 hours after treatment can result in higher cortisol concentrations that could support continued trilostane treatment.     

1例犬的急性肾损伤病例的诊断和治疗

介绍了1例临床表现为持续高烧、呕吐、肌肉强直的患犬,通过全面的一般检查、X光检查、B超检查和实验室检查,疑似为由急性肾衰竭引起的肾损伤。在保肾、利尿的原则下,进行诊断性治疗,消除临床症状,该犬最终痊愈出院。     

Electrolyte Disturbances in Foals with Severe Rhabdomyolysis

Marked electrolyte abnormalities characterized by profound hyperkalemia, hyponatremia, hypocalcemia, and hyperphosphatemia were noted in 4 neonatal foals with acute rhabdomyolysis and pigmenturia. In 2 foals, rhabdomyolysis developed 4–6 days after admission for dysmaturity, and in 2 foals, rhabdomyolysis was evident on presentation. Rhabdomyolysis was a consequence of selenium deficiency with or without vitamin E deficiency, possibly combined with increased oxidant stress due to sepsis or hypoxia and reperfusion injury after parturition. Foals gained from 7 to 15% of their initial body weight within 48 hours of developing rhabdomyolysis. Three of the foals developed cardiac arrhythmias characterized by spiked T waves and decreased-amplitude P waves. Postmortem examination of 2 foals revealed extensive myodegeneration and renal tubular nephrosis; renal cortical necrosis with myocardial necrosis was noted in 1 foal. Destruction of the major intracellular compartment (intracellular fluid [ICF]) through extensive myonecrosis combined, in some cases, with myoglobinuric renal insufficiency produced major fluid shifts and life-threatening electrolyte derangements. With the major ICF compartment disrupted, hyperkalemia was most effectively treated using mineralocorticoids, loop diuretics, and ion exchange resins to enhance elimination. In addition, IV calcium, glucose, insulin, and sodium bicarbonate were administered, which helped redistribute potassium to the ICE Severe rhabdomyolysis should be included in the differential diagnoses of hyperkalemia, hyponatremia, hypocalcemia, and hyperphosphatemia in neonatal foals.     

Effects of Ginkgo leaf extract and dipyridamole injection on tension of thoracic aorta rings of rats with hyperkalemia

AIM: To investigate the effects of Ginkgo leaf extract and dipyridamole injection (GD) on the tension of thoracic aorta rings isolated from hyperkalemia rats(HKR).METHODS: After the model of HKR was established and the preparation of the thoracic aorta rings was made, the tension of the rings was measured by a biological signal analytical system. The thoracic aorta rings were exposed to the medium containing GD at different concentrations and the vaso-constrictive tension was observed after stimulated with phenylephrine (PE) or KCl. RESULTS: Stimulated with PE or KCl, the tension of the thoracic aorta rings in HKR group was significantly higher than that in normal group (P<0.05). GD at the concentrations used in the experiment did not affect the basal tension in the resting rings prepared from both HKR and normal rats. In HKR group, pretreatment of the endothelium-intact thoracic aorta rings with GD at different concentrations showed no significant effect on KCl-induced vessel constriction (P>0.05). However, GD at the concentration of 16 mg/L significantly attenuated the vessel constriction induced by PE (P<0.05), which was inhibited by the pretreatment with N^ω-nitro-L-arginine methylester or methylene blue. GD at different concentrations did not show significantly inhibitory effect on PE-induced tension of endothelium-denuded thoracic aorta rings in HKR group (P>0.05). CONCLUSION: GD causes endothelium-dependent relaxation in the thoracic aorta rings of HKR. This effect may be mediated by the nitricoxide-guanylyl cyclase pathway.     

Accuracy of Potassium Supplementation of Fluids Administered Intravenously

Background

Potassium (K⁺) supplementation of isotonic crystalloid fluids in daily fluid therapy is commonly performed, yet its accuracy in veterinary medicine is undetermined.

Objective

To investigate the accuracy of K⁺ supplementation in isotonic crystalloid fluids.

Animals

None.

Methods

Observational study. 210 bags of fluid supplemented with KCl being administered to hospitalized dogs and cats intravenously (IV) were sampled over a 3‐month period. Measured K⁺ concentration ([K⁺]) was compared to the intended [K⁺] of the bag. In a second experiment, 60 stock fluid bags were supplemented to achieve a concentration of 20 mmol/L K⁺, mixed well and [K⁺] was measured. In another 12 bags of 0.9% NaCl, K⁺ was added without mixing the bag, and [K⁺] of the delivered fluid was measured at regular time points during constant rate infusion.

Results

The measured [K⁺] was significantly higher than intended [K⁺] (mean difference 9.0 mmol/L, range 6.5 to >280 mmol/L, P < .0001). In 28% of clinical samples measured [K⁺] was ≥5 mmol/L different than intended [K⁺]. With adequate mixing, K⁺ supplementation of fluids can be accurate with the mean difference between measured and intended [K⁺] of 0.7 (95% CI −0.32 to 1.7) mmol/L. When not mixed, K⁺ supplementation of 20 mmol/L can lead to very high [K⁺] of delivered fluid (up to 1410 mmol/L).

Conclusions and Clinical Importance

Inadequate mixing following K⁺ supplementation of fluid bags can lead to potentially life threatening IV infused [K⁺]. Standard protocols for K⁺ supplementation should be established to ensure adequate mixing.     

不同护理方法对术后瘘管羊恢复效果的影响

通过比较两种不同护理方法对奶山羊瘘管手术后恢复效果的影响,从术后动物的促醒,青霉素消炎的方法,青霉素的过敏反应机理,青霉素钾、青霉素钠、生理盐水和葡萄糖溶液的使用,不同的输液速度等方面进行了比较和分析,在总结经验的基础上,提出了一套正确的护理方法和用药措施,为提高瘘管手术的成功率提供了有价值的参考依据。     

Effects of Alkalinization and Rehydration on Plasma Potassium Concentrations in Neonatal Calves with Diarrhea

Background

Increased plasma potassium concentrations (K⁺) in neonatal calves with diarrhea are associated with acidemia and severe clinical dehydration and are therefore usually corrected by intravenous administration of fluids containing sodium bicarbonate.

Objectives

To identify clinical and laboratory variables that are associated with changes of plasma K⁺ during the course of treatment and to document the plasma potassium‐lowering effect of hypertonic (8.4%) sodium bicarbonate solutions.

Animals

Seventy‐one neonatal diarrheic calves.

Methods

Prospective cohort study. Calves were treated according to a clinical protocol using an oral electrolyte solution and commercially available packages of 8.4% sodium bicarbonate (250–750 mmol), 0.9% saline (5–10 L), and 40% dextrose (0.5 L) infusion solutions.

Results

Infusions with 8.4% sodium bicarbonate solutions in an amount of 250–750 mmol had an immediate and sustained plasma potassium‐lowering effect. One hour after the end of such infusions or the start of a sodium bicarbonate containing constant drip infusion, changes of plasma K⁺ were most closely correlated to changes of venous blood pH, plasma sodium concentrations and plasma volume (r = −0.73, −0.57, −0.53; P < .001). Changes of plasma K⁺ during the subsequent 23 hours were associated with changes of venous blood pH, clinical hydration status (enophthalmos) and serum creatinine concentrations (r = −0.71, 0.63, 0.62; P < .001).

Conclusions and Clinical Importance

This study emphasizes the importance of alkalinization and the correction of dehydration in the treatment of hyperkalemia in neonatal calves with diarrhea.