Elke Rudloff

Evaluation of initial plasma lactate values as a predictor of gastric necrosis and initial and subsequent plasma lactate values as a predictor of survival in dogs with gastric dilatation-volvulus: 84 dogs (2003–2007)

OBJECTIVE To test whether an initial plasma lactate ≥ 6.0 mmol/L is associated with the presence of macroscopic gastric wall necrosis and overall survival in dogs presenting with gastric dilatation-volvulus (GDV). Additionally, if no association was identified we sought to identify a different predictive initial plasma lactate concentration and to examine whether serial plasma lactate concentrations provide better prediction of survival. DESIGN Retrospective study over a 5-year period (2003-2007). SETTING Urban private referral small animal teaching hospital. ANIMALS Eighty-four client-owned dogs with a diagnosis of GDV and plasma lactate measurements. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS There was no statistically significant relationship found between survival and the presence of macroscopic gastric wall necrosis with the initial plasma lactate ≥ 6 mmol/L. There was a significant relationship between the initial plasma lactate >2.9 mmol/L for predicting necrosis and <4.1 mmol/L for predicting survival to discharge. Forty dogs that had an increased initial plasma lactate (>2.5 mmol/L) also had a subsequent plasma lactate measured within 12 hours of presentation, with 37/40 dogs surviving and 70% of these surviving dogs having the subsequent lactate decrease by ≥ 50% within 12 hours. The 3/40 that died failed to decrease their plasma lactate by ≥ 50% from the initial blood lactate. CONCLUSION The results of this study indicate that an initial presenting plasma lactate concentration ≥ 6.0 mmol/L is not predictive of macroscopic gastric wall necrosis or survival in dogs presenting with GDV. A decrease in plasma lactate concentrations ≥ 50% within 12 hours may be a good indicator for survival. Limitations to the study include its retrospective nature, the small number of patients, and the number of dogs that were euthanized rather than allowed to progress to a natural outcome.

Hydroxyethyl starch: A review of pharmacokinetics, pharmacodynamics, current products, and potential clinical risks, benefits, and use

Objective To review and summarize the pharmacokinetics and pharmacodynamics of hydroxyethyl starch (HES), as well as reported risks and benefits of HES infusion, and to provide administration and monitoring recommendations for HES use in dogs and cats. Data Sources Veterinary and human peer-reviewed medical literature, including scientific reviews, clinical and laboratory research articles, and authors’ clinical experience. Summary HES solutions are the most frequently used synthetic colloid plasma volume expanders in human and veterinary medicine. The majority of research in human medicine has focused on the adverse effects of HES infusion, with emphasis on acute kidney injury and coagulation derangements. The studies often differ in or fail to report factors, such as the type, amount, interval, and concentration of HES administered; the patient population studied; or concurrent fluids administered. Currently, there is no definitive clinical evidence that the reported adverse effects of HES use in human medicine occur in veterinary species. There is little information available on HES administration techniques or simultaneous administration of additional fluids in human and veterinary medicine. The rationale for HES use in small animals has been largely extrapolated from human medical studies and guidelines. A controlled approach to intravenous fluid resuscitation using crystalloid and HES volumes titrated to reach desired resuscitation end point parameters is outlined for small animal practitioners. Conclusion The extrapolation of data from human studies directly to small animals should be done with the knowledge that there may be species variations and different pharmacokinetics with different HES solutions. Veterinary reports indicate that bolus and continuous rate infusions of 6% hetastarch solutions at moderate doses are well tolerated in feline and canine subjects. Further research in domesticated species is necessary to better define and expand the knowledge regarding use of HES solutions in small animal medicine.

The role of aquaporin 4 in the brain

Emerging evidence suggests that aquaporin (AQP) 4 water channels play an important role in water homeostasis in the brain. These water channels are most abundant in the cell membrane of astrocytes, but are also present within ependymal cell membranes and in osmosensory areas of the hypothalamus. Water transport through AQP4 depends on concentration gradients across the membrane, but the rate of transport is determined by the capacity of astrocytes to up- and down-regulate AQP4 numbers, their location within the membrane, and the overall permeability of the channel. Other functions of brain AQP4 involve potassium uptake and release by astrocytes, migration of glial cells, glial scarring, and astrocyte-to-astrocyte cell communication. AQP water channels are involved in formation and control of edema in the brain and in multiple disease processes in the brain, such as seizures and tumors. There is abundant scientific literature on AQP4 describing its structure, function, location, and role in water homeostasis and edema in the brain. Investigation of AQP expression in the canine and feline brain should be pursued so that clinically relevant comparisons between findings in mice, rats, and people and animal patients can be made.

Nasogastric tube feeding in cats with suspected acute pancreatitis: 55 cases (2001–2006)

OBJECTIVE To evaluate the complications and outcome associated with different nasogastric tube (NGT) feeding techniques in cats with suspected acute pancreatitis. DESIGN Descriptive retrospective case series. SETTING Small animal emergency and referral hospital. ANIMALS The patient database (2001-2006) was searched for cats with suspected acute pancreatitis that received NGT liquid enteral feeding within 72 hours of admission and ≥12 hours during hospitalization. MEASUREMENTS AND MAIN RESULTS Signalment, history, clinical signs, laboratory data and abdominal ultrasonographic examinations were used for suspected diagnosis. Cats were grouped based upon whether they received bolus feeding or continuous rate infusion (CRI) of a liquid diet via the NGT, and whether or not administration of an intravenous amino acid and carbohydrate solution occurred prior to NGT feeding (AAS and non-AAS group, respectively). Fifty-five cats were included. For all cats, NGT feeding was initiated at a mean of 33.5 ± 15.0 hours and the target caloric intake (1.2 X {(30 X BW [kg]) +70}) was reached at 58.0 ± 28.4 hours from presentation. There was a significantly longer time from admission to the initiation of NGT feeding in the 34/55 cats in the AAS group vs. the 21/55 cats in the non-AAS group (P = 0.009). The 8 bolus-fed cats took longer to reach target caloric intake vs. the 47 CRI-fed cats (P = 0.002). Complications associated with NGT feeding for all cats included: mechanical problems (13%), diarrhea (25%), vomiting following NGT placement (20%) and vomiting following NGT feeding (13%). Mean time to discharge for all cats occurred after 78.6 ± 29.5 hours with an overall weight gain of 0.08 ± 0.52 kg. Fifty cats survived 28 days post-discharge. CONCLUSIONS NGT feeding in this group of cats with suspected acute pancreatitis was well tolerated, and associated with a low incidence of diarrhea, vomiting, and mechanical complications.

Fluid Therapy: Crystalloids and Colloids

Appropriate fluid therapy requires an understanding of fluid dynamics and pathologic alterations during various disease states. In addition, it requires an understanding of the pharmacologic differences of available fluids. Crystalloid fluids and colloid fluids can be used in combination to treat a variety of volume-deficient states. Synthetic colloids are also used to treat hyponcotic states. Blood products are used to replace blood components and coagulation proteins. Frequent monitoring and reassessment are required to prevent volume overload and life-threatening edema.

Evaluation of the effects of bovine hemoglobin glutamer-200 on systolic arterial blood pressure in hypotensive cats: 44 cases (1997-2008)

OBJECTIVE To determine effects of bovine hemoglobin glutamer-200 (Hb-200) solution on systolic arterial blood pressure (SAP) in hypotensive cats and describe potential adverse effects associated with this treatment. DESIGN Retrospective case series. ANIMALS 44 cats. PROCEDURES Medical records of hypotensive (Doppler SAP ≤ 80 mm Hg) cats that received Hb-200 treatment were reviewed. Volume and rate of Hb-200 administration, treatments for hypotension given prior to Hb-200 administration, changes in SAP, potential adverse effects, and short-term outcome were evaluated. RESULTS 44 cats were included in the study. Mean ± SD SAP prior to Hb-200 administration was 52 ± 11 mm Hg, despite other treatments. Forty-three cats received Hb-200 via IV bolus administration (mean ± SD volume, 3.1 ± 2.2 mL/kg [1.41 ± 1.0 mL/lb] over 25.17 ± 17.51 minutes); 1 cat received a continuous rate infusion (CRI) only. The SAP increased to > 80 mm Hg in 33 of 44 (75%) cats. The SAP increased > 20 mm Hg above baseline value in 29 of these 33 cats and in 4 cats in which SAP did not exceed 80 mm Hg. A CRI (mean ± SD rate, 0.8 ± 0.5 mL/kg/h [0.36 ± 0.23 mL/lb/h]) of Hb-200 was administered to 37 cats (after bolus infusion in 36). Mean SAP during the CRI was 92 ± 18 mm Hg. Adverse effects included respiratory changes (n = 8 cats), vomiting (2), and pigmented serum (30). Seventeen (39%) cats survived to discharge from the hospital, 6 died, and 21 were euthanized. CONCLUSIONS AND CLINICAL RELEVANCE Hb-200 effectively increased SAP in hypotensive cats with few adverse effects.

Comparison of Hb‐200 and 6% hetastarch 450/0.7 during initial fluid resuscitation of 20 dogs with gastric dilatation‐volvulus

Objective To compare the use of polymerized stroma-free bovine hemoglobin (Hb-200) and 6% hetastarch 450/0.7 (HES 450/0.7) in 0.9% saline during fluid resuscitation of dogs with gastric dilatation-volvulus (GDV). Design Prospective, randomized clinical case series. Setting Private specialty and referral clinic. Animals Twenty client-owned dogs presenting with GDV. Interventions Dogs presenting with GDV and abnormal perfusion parameters first received rapid IV infusion of a buffered isotonic replacement crystalloid (15 mL/kg) and IV opioids. Patients were then randomized to receive either Hb-200 (N = 10) or HES 450/0.7 (N = 10). Balanced isotonic replacement crystalloids (10–20 mL/kg IV) were rapidly infused along with either Hb-200 or HES in 5 mL/kg IV aliquots to meet resuscitation end points. Measurements and Main Results Resuscitation was defined as meeting at least 2 of 3 criteria: (1) capillary refill time 1–2 seconds, pink mucous membrane color, strong femoral pulse quality; (2) heart rate (HR) ≤ 150/min; or (3) indirect arterial systolic blood pressure (SBP) > 90 mm Hg. HR, SBP, packed cell volume, hemoglobin, glucose, venous pH, bicarbonate, base excess, anion gap, and colloid osmotic pressure were compared at hospital entry and within 30 minutes post-resuscitation. Compared to the HES group, the Hb-200 group required significantly less colloid (4.2 versus 18.4 mL/kg) and crystalloid (31.3 versus 48.1 mL/kg) to reach resuscitation end points (P = 0.001). Time to resuscitation was significantly shorter in the Hb-200 group (12.5 versus 52.5 min). Conclusions Dogs with GDV receiving Hb-200 during initial resuscitation required smaller volumes of both crystalloid and colloid fluids and reached resuscitation end points faster than dogs receiving HES 450/0.7 (P = 0.02).OBJECTIVE To compare the use of polymerized stroma-free bovine hemoglobin (Hb-200) and 6% hetastarch 450/0.7 (HES 450/0.7) in 0.9% saline during fluid resuscitation of dogs with gastric dilatation-volvulus (GDV). DESIGN Prospective, randomized clinical case series. SETTING Private specialty and referral clinic. ANIMALS Twenty client-owned dogs presenting with GDV. INTERVENTIONS Dogs presenting with GDV and abnormal perfusion parameters first received rapid IV infusion of a buffered isotonic replacement crystalloid (15 mL/kg) and IV opioids. Patients were then randomized to receive either Hb-200 (N = 10) or HES 450/0.7 (N = 10). Balanced isotonic replacement crystalloids (10-20 mL/kg IV) were rapidly infused along with either Hb-200 or HES in 5 mL/kg IV aliquots to meet resuscitation end points. MEASUREMENTS AND MAIN RESULTS Resuscitation was defined as meeting at least 2 of 3 criteria: (1) capillary refill time 1-2 seconds, pink mucous membrane color, strong femoral pulse quality; (2) heart rate (HR) ≤ 150/min; or (3) indirect arterial systolic blood pressure (SBP) > 90 mm Hg. HR, SBP, packed cell volume, hemoglobin, glucose, venous pH, bicarbonate, base excess, anion gap, and colloid osmotic pressure were compared at hospital entry and within 30 minutes post-resuscitation. Compared to the HES group, the Hb-200 group required significantly less colloid (4.2 versus 18.4 mL/kg) and crystalloid (31.3 versus 48.1 mL/kg) to reach resuscitation end points (P = 0.001). Time to resuscitation was significantly shorter in the Hb-200 group (12.5 versus 52.5 min). CONCLUSIONS Dogs with GDV receiving Hb-200 during initial resuscitation required smaller volumes of both crystalloid and colloid fluids and reached resuscitation end points faster than dogs receiving HES 450/0.7 (P = 0.02).

Magnesium physiology and clinical therapy in veterinary critical care

OBJECTIVE To review magnesium physiology including absorption, excretion, and function within the body, causes of magnesium abnormalities, and the current applications of magnesium monitoring and therapy in people and animals. ETIOLOGY Magnesium plays a pivotal role in energy production and specific functions in every cell in the body. Disorders of magnesium can be correlated with severity of disease, length of hospital stay, and recovery of the septic patient. Hypermagnesemia is seen infrequently in people and animals with significant consequences reported. Hypomagnesemia is more common in critically ill people and animals, and can be associated with platelet, immune system, neurological, and cardiovascular dysfunction as well as alterations in insulin responsiveness and electrolyte imbalance. DIAGNOSIS Measurement of serum ionized magnesium in critically or chronically ill veterinary patients is practical and provides information necessary for stabilization and treatment. Tissue magnesium concentrations may be assessed using nuclear magnetic resonance spectroscopy as well as through the application of fluorescent dye techniques. THERAPY Magnesium infusions may play a therapeutic role in reperfusion injury, myocardial ischemia, cerebral infarcts, systemic inflammatory response syndromes, tetanus, digitalis toxicity, bronchospasms, hypercoagulable states, and as an adjunct to specific anesthetic or analgesic protocols. Further veterinary studies are needed to establish the frequency and importance of magnesium disorders in animals and the potential benefit of magnesium infusions as a therapeutic adjunct to specific diseases. PROGNOSIS The prognosis for most patients with magnesium disorders is variable and largely dependent on the underlying cause of the disorder.Objective To review magnesium physiology including absorption, excretion, and function within the body, causes of magnesium abnormalities, and the current applications of magnesium monitoring and therapy in people and animals. Etiology Magnesium plays a pivotal role in energy production and specific functions in every cell in the body. Disorders of magnesium can be correlated with severity of disease, length of hospital stay, and recovery of the septic patient. Hypermagnesemia is seen infrequently in people and animals with significant consequences reported. Hypomagnesemia is more common in critically ill people and animals, and can be associated with platelet, immune system, neurological, and cardiovascular dysfunction as well as alterations in insulin responsiveness and electrolyte imbalance. Diagnosis Measurement of serum ionized magnesium in critically or chronically ill veterinary patients is practical and provides information necessary for stabilization and treatment. Tissue magnesium concentrations may be assessed using nuclear magnetic resonance spectroscopy as well as through the application of fluorescent dye techniques. Therapy Magnesium infusions may play a therapeutic role in reperfusion injury, myocardial ischemia, cerebral infarcts, systemic inflammatory response syndromes, tetanus, digitalis toxicity, bronchospasms, hypercoagulable states, and as an adjunct to specific anesthetic or analgesic protocols. Further veterinary studies are needed to establish the frequency and importance of magnesium disorders in animals and the potential benefit of magnesium infusions as a therapeutic adjunct to specific diseases. Prognosis The prognosis for most patients with magnesium disorders is variable and largely dependent on the underlying cause of the disorder.

Comparison of esophageal Doppler monitor generated minute distance and cardiac output in a porcine model of ventricular fibrillation

The primary goal of cardiopulmonary resuscitation (CPR) is to increase cardiac output (CO), providing adequate tissue perfusion and oxygenation to maintain normal organ function. A non-invasive, easy to use, commercially available esophageal doppler monitor (EDM, Deltex) has been found to provide minute distance (MD), which is the distance moved by a column of blood through the aorta in 1 min. The goal of our study was to determine if CO measurements correlate with the EDM MD, before and during cardiac arrest, in a porcine model of ventricular fibrillation. Twenty pigs were anesthetized and an EDM was placed. MD measurement using EDM, and CO measurement using florescent microsphere injections were compared before and during CPR. MD correlated well with CO (r2 = 0.96) before and during CPR. Based on the excellent correlation between MD as determined by EDM and CO by florescent microsphere technique, it appears that the non-invasive use of the EDM may play a valuable role in determination of CO during CPR.

Airway obstruction in a dog after Dieffenbachia ingestion.

OBJECTIVE To describe a case of Dieffenbachia ingestion in a dog presented for dysphagia and airway obstruction successfully treated with a temporary tracheostomy and supportive care beyond that reported in the veterinary literature. CASE SUMMARY An 8-year-old male neutered Labrador Retriever, weighing 30 kg, was presented with the complaint of choking and gagging. Abdominal radiographs showed that he had a distended stomach full of foreign material and a gastrotomy was performed. After receiving preanesthetic medication, the dog developed inspiratory stridor and during anesthetic induction, marked oropharyngeal swelling complicated tracheal intubation. During surgery a large amount of dog bedding and Dieffenbachia plant material was removed. Because of the severity of the oropharyngeal swelling, the dog required a temporary tracheostomy and treatment for an acute allergic reaction related to the Dieffenbachia ingestion. The patient was discharged after 6 days in the hospital and had no significant complications. NEW OR UNIQUE INFORMATION PROVIDED To our knowledge, this is the first reported case of successful treatment of an airway obstruction related to the toxicity of Dieffenbachia ingestion.