Controversies in the use of hydroxyethyl starch solutions in small animal emergency and critical care

OBJECTIVES: To (1) review the development and medical applications of hydroxyethyl starch (HES) solutions with particular emphasis on its physiochemical properties; (2) critically appraise the available evidence in human and veterinary medicine, and (3) evaluate the potential risks and benefits associated with their use in critically ill small animals. DATA SOURCES: Human and veterinary original research articles, scientific reviews, and textbook sources from 1950 to the present. HUMAN DATA SYNTHESIS: HES solutions have been used extensively in people for over 30 years and ever since its introduction there has been a great deal of debate over its safety and efficacy. Recently, results of seminal trials and meta-analyses showing increased risks related to kidney dysfunction and mortality in septic and critically ill patients, have led to the restriction of HES use in these patient populations by European regulatory authorities. Although the initial ban on the use of HES in Europe has been eased, proof regarding the benefits and safety profile of HES in trauma and surgical patient populations has been requested by these same European regulatory authorities. VETERINARY DATA SYNTHESIS: The veterinary literature is limited mostly to experimental studies and clinical investigations with small populations of patients with short-term end points and there is insufficient evidence to generate recommendations. CONCLUSIONS: Currently, there are no consensus recommendations regarding the use of HES in veterinary medicine. Veterinarians and institutions affected by the HES restrictions have had to critically reassess the risks and benefits related to HES usage based on the available information and sometimes adapt their procedures and policies based on their reassessment. Meanwhile, large, prospective, randomized veterinary studies evaluating HES use are needed to achieve relevant levels of evidence to enable formulation of specific veterinary guidelines.

Retrospective evaluation of postoperative nasotracheal tubes for oxygen supplementation in dogs following surgery for brachycephalic syndrome: 36 cases (2003-2007)

OBJECTIVE: To assess the utility of nasotracheal tubes in postoperative oxygen supplementation in dogs following corrective surgery for brachycephalic syndrome. DESIGN: Retrospective study 2003-2007. SETTING: University teaching hospital. ANIMALS: Thirty-six client-owned dogs that underwent corrective surgery for brachycephalic syndrome. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Medical records were reviewed for animals that underwent surgical interventions for brachycephalic syndrome including palatoplasty, ventriculectomy, and rhinoplasty. Data collected included signalment, presenting complaints, analgesic and surgical interventions, type of supplemental oxygen therapy, complications and mortality occurring during hospitalization. A nasotracheal tube (NTT) was placed in 20 dogs at the end of surgery; 16 dogs received other forms of oxygen supplementation (8) or no oxygen supplementation (8) during recovery. The total number of postoperative complications was similar in both groups (8/20 dogs with NTTs and 7/16 in those without NTTs). However, respiratory distress was observed in 5 dogs without NTTs but was not observed in any dog while an NTT was in place. One dog in each group died postoperatively. CONCLUSION: Placement of an NTT was found to be easy and may offer benefit in dogs with brachycephalic syndrome as a noninvasive means of delivering oxygen. The use of NTT may minimize severe postoperative morbidity, in particular by reducing postoperative respiratory distress.

Evaluation of respiratory parameters at presentation as clinical indicators of the respiratory localization in dogs and cats with respiratory distress

OBJECTIVE: To describe clinical respiratory parameters in cats and dogs with respiratory distress and identify associations between respiratory signs at presentation and localization of the disease with particular evaluation between the synchrony of abdominal and chest wall movements as a clinical indicators for pleural space disease. Design - Prospective observational clinical study. SETTING: Emergency service in a university veterinary teaching hospital. ANIMALS: Cats and dogs with respiratory distress presented to the emergency service between April 2008 and July 2009. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The following parameters were systematically determined at time of admission: respiratory rate, heart rate, temperature, type of breathing, movement of the thoracic and abdominal wall during inspiration, presence of stridor, presence and type of dyspnea, and results of thoracic auscultation. Abdominal and chest wall movement was categorized as synchronous, asynchronous, or inverse. Diagnostic test results, diagnosis, and outcome were subsequently recorded. Based on the final diagnoses, animals were assigned to 1 or more of the following groups regarding the anatomical localization of the respiratory distress: upper airways, lower airways, lung parenchyma, pleural space, thoracic wall, nonrespiratory causes, and normal animals. One hundred and seventy-six animals (103 cats and 73 dogs) were evaluated. Inspiratory dyspnea was associated with upper airway disease in dogs and expiratory dyspnea with lower airway disease in cats. Respiratory noises were significantly associated and highly sensitive and specific for upper airway disease. An asynchronous or inverse breathing pattern and decreased lung auscultation results were significantly associated with pleural space disease in both dogs and cats (P<0.001). The combination is highly sensitive (99%) but not very specific (45%). Fast and shallow breathing was not associated with pleural space disease. Increased or moist pulmonary auscultation findings were associated with parenchymal lung disease. CONCLUSIONS: Cats and dogs with pleural space disease can be identified by an asynchronous or inverse breathing pattern in combination with decreased lung sounds on auscultation.

European outbreak of atypical myopathy in the autumn 2009

BACKGROUND: Atypical myopathy is an acute, severe rhabdomyolysis occurring in grazing horses. In the beginning of October 2009, a new outbreak occurred in several European countries. Geographic, demographic and clinical data of the reported cases in the month October 2009 are described. KEY FINDINGS: The survival rate in this outbreak was 25%. The most frequently observed clinical signs were congested mucous membranes, dyspnea, tachycardia, depression, weakness, stiffness, recumbency, trembling, sweating, and myoglobinuria. Nonsurvivors were significantly more likely to be recumbent than survivors. Prognostic factors, symptomatic treatment, and preventive measures are discussed. SIGNIFICANCE: Differences were encountered during the described outbreak of atypical myopathy in October 2009 compared with previous outbreaks reported. Equine practitioners should be aware that previous epidemiological studies have shown that after a high prevalence in the autumn, new cases are likely to occur in the following spring.

Right ventricular rupture after lateral thoracotomy for removal of rib-associated telangiectatic osteosarcoma in a dog

OBJECTIVE: To describe a case of a focal right ventricular rupture following removal of a rib-associated telangiectatic osteosarcoma (TOS) in a dog. CASE SUMMARY: A 2-year-old spayed female mixed-breed dog, weighing 20 kg, was presented in compensated hypovolemic shock due to active bleeding into the thoracic cavity. The dog was stabilized with appropriate fluid administration. Subsequent computed tomographic examination revealed a large mineralized mass originating from the body of a rib and displacing the heart. Two days after surgical removal of this mass, focal right ventricular rupture occurred and the dog died. The mass was later identified as a TOS. NEW OR UNIQUE INFORMATION PROVIDED: Although hemothorax secondary to TOS has been described previously, this report describes for the first time, spontaneous focal right ventricular rupture as a rare complication of thoracotomy and rib resection for the removal of a rib-associated, intrathoracic TOS.

Myoglobin as a prognostic indicator for outcome in dogs with gastric dilatation-volvulus

OBJECTIVE: To determine whether myoglobin (Mb) is a useful prognostic indicator for outcome and to investigate any relationship between Mb and mortality in dogs with gastric dilatation-volvulus (GDV). DESIGN: Prospective study. SETTING: Veterinary teaching hospital. ANIMALS: Seventy-two dogs with GDV. INTERVENTIONS: Blood sampling. MEASUREMENTS AND MAIN RESULTS: Mb levels were measured at the time of diagnosis (Mbt0), 24 hours (Mbt1), and 48 hours (Mbt2) after signs of GDV were recognized. Fifty-seven dogs survived (group I) and 15 dogs did not survive (group II). Mbt0 differed significantly between groups (P=0.04). Mbt0 in group I ranged from <30 to >700 ng/mL (n=57, median 74 ng/mL), and in group II from 34 to >700 ng/mL (n=15, median 238 ng/mL). Analysis of a receiver operating characteristic curve of Mbt0 suggested that the best single cutpoint would be 168 ng/mL (sensitivity 60.0%, specificity 84.2%). Fifty percent of dogs with Mbt0>168 ng/mL were euthanized, while 88.9% with Mbt0<168 ng/mL survived. Mbt1 and Mbt2 differed significantly between groups I and II. Mbt1 in group I ranged from 32 to >700 ng/mL (n=55, median 123 ng/mL), and Mbt1 in group II ranged from 131 to 643 ng/mL (n=7, median 343 ng/mL) (P=0.006). Mbt2 in group I ranged from 30 to 597 ng/mL (n=54, median 101 ng/mL), and in group II from 141 to >700 ng/mL (n=8, median 203 ng/mL) (P=0.02). CONCLUSIONS: In this study, Mbt0 is a moderately sensitive and specific prognostic indicator. Almost 90% of the dogs below the cutpoint survived to discharge, whereas 50% with Mbt0 above the cutpoint did not survive.

Small intestinal intussusception in five dogs with acute renal failure and suspected leptospirosis (L. australis)

OBJECTIVES This case series describes 5 dogs with small intestinal intussusception and acute kidney injury due to infection with Leptospira interrogans serovar Australis. CASE SERIES SUMMARY Small intestinal intussusception was observed in 4 dogs diagnosed with acute kidney injury due to leptospirosis presented between 1997 and 2005. Intussusception was diagnosed at initial presentation or later during hospitalization. An additional dog fulfilling our inclusion criteria was presented to a small animal specialty clinic nearby and was included. Upon admission, all dogs were severely azotemic and thrombocytopenic. All 5 dogs showed the strongest microscopic agglutination test serology reaction to L. interrogans serovar Australis. Two dogs survived with no apparent residual renal damage, 1 survived with subsequent mild chronic kidney disease, and 2 dogs were euthanized at the owners' request due to a guarded prognosis. NEW OR UNIQUE INFORMATION PROVIDED Intussusception can occur or may be seen in dogs with leptospirosis due to L. interrogans serovar Australis and patients should be monitored closely for this potential complication. As all 5 dogs described in this case series showed the highest titer for L. interrogans serovar Australis, these precautions may be especially applied in geographic areas where this particular serovar is seen.

Clinical findings and diagnostic value of post-traumatic thoracic radiographs in dogs and cats with blunt trauma

Objective: To characterize the clinical findings in dogs and cats that sustained blunt trauma and to compare clinical respiratory examination results with post-traumatic thoracic radiography findings. Design: Retrospective clinical study. Setting: University small animal teaching hospital. Animals, interventions and measurements: Case records of 63 dogs and 96 cats presenting with a history of blunt trauma and thoracic radiographs between September 2001 and May 2003 were examined. Clinical signs of respiratory distress (respiratory rate (RR), pulmonary auscultation) and outcome were compared with radiographic signs of blunt trauma. Results: Forty-nine percent of dogs and 63.5% of cats had radiographic signs attributed to thoracic trauma. Twenty-two percent of dogs and 28% of cats had normal radiographs. Abnormal auscultation results were significantly associated with radiographic signs of thoracic trauma, radiography score and presence and degree of contusions. Seventy-two percent of animals with no other injuries showed signs of thoracic trauma on chest radiographs. No correlation was found between the radiographic findings and outcome, whereas the trauma score at presentation was significantly associated with outcome and with signs of chest trauma but not with the radiography score. Conclusion: Thoracic trauma is encountered in many blunt trauma patients. The RR of animals with blunt trauma is not useful in predicting thoracic injury, whereas abnormal chest auscultation results are indicative of chest abnormalities. Thorough chest auscultation is, therefore, mandatory in all trauma animals and might help in the assessment of necessity of chest radiographs.

Comparison of the in vitro effects of saline, hypertonic hydroxyethyl starch, hypertonic saline, and two forms of hydroxyethyl starch on whole blood coagulation and platelet function in dogs.

OBJECTIVE To compare the in vitro effects of hypertonic solutions and colloids to saline on coagulation in dogs. DESIGN In vitro experimental study. SETTING Veterinary teaching hospital. ANIMALS Twenty-one adult dogs. INTERVENTIONS Blood samples were diluted with saline, 7.2% hypertonic saline solution with 6% hydroxyethylstarch with an average molecular weight of 200 kDa and a molar substitution of 0.4 (HH), 7.2% hypertonic saline (HTS), hydroxyethyl starch (HES) 130/0.4 or hydroxyethyl starch 600/0.75 at ratios of 1:22 and 1:9, and with saline and HES at a ratio of 1:3. MEASUREMENTS AND MAIN RESULTS Whole blood coagulation was analyzed using rotational thromboelastometry (extrinsic thromboelastometry-cloting time (ExTEM-CT), maximal clot firmness (MCF) and clot formation time (CFT) and fibrinogen function TEM-CT (FibTEM-CT) and MCF) and platelet function was analyzed using a platelet function analyzer (closure time, CTPFA ). All parameters measured were impaired by saline dilution. The CTPFA was prolonged by 7.2% hypertonic saline solution with 6% hydroxyethylstarch with an average molecular weight of 200 kDa and a molar substitution of 0.4 (HH) and HTS but not by HES solutions. At clinical dilutions equivalent to those generally administered for shock (saline 1:3, HES 1:9, and hypertonic solutions 1:22), CTPFA was more prolonged by HH and HTS than other solutions but more by saline than HES. No difference was found between the HES solutions or the hypertonic solutions. ExTEM-CFT and MCF were impaired by HH and HTS but only mildly by HES solutions. At clinically relevant dilutions, no difference was found in ExTEM-CFT between HTS and saline or in ExTEM-MCF between HH and saline. No consistent difference was found between the 2 HES solutions but HH impaired ExTEM-CFT and MCF more than HTS. At high dilutions, FibTEM-CT and -MCF and ExTEM-CT were impaired by HES. CONCLUSIONS Hypertonic solutions affect platelet function and whole blood coagulation to a greater extent than saline and HES. At clinically relevant dilutions, only CTPFA was markedly more affected by hypertonic solutions than by saline. At high dilutions, HES significantly affects coagulation but to no greater extent than saline at clinically relevant dilutions.

Retrospective evaluation of the effects of administration of tetrastarch (hydroxyethyl starch 130/0.4) on plasma creatinine concentration in dogs (2010-2013): 201 dogs

OBJECTIVE To determine changes in creatinine concentrations following the administration of 6% tetrastarch (hydroxyethyl starch [HES] 130/0.4) compared to crystalloids (CRYSs) in critically ill dogs. DESIGN Retrospective case series (2010-2013). SETTING University teaching hospital. ANIMALS Two hundred and one dogs admitted to the intensive care unit with initial plasma creatinine concentrations not exceeding laboratory reference intervals (52-117 μmol/L [0.6-1.3 mg/dL]) and receiving either CRYSs alone (CRYS group, n = 115) or HES with or without CRYSs (HES group, n = 86) for at least 24 hours. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Creatinine concentrations at admission to the intensive care unit (T0), and 2-13 days (T1) and 2-12 weeks (T2) after initiation of fluid therapy were analyzed. Creatinine concentrations were analyzed as absolute values and as the maximum percentage change from T0 to T1 (T1max%) and from T0 to T2 (T2max%), respectively. Creatinine concentrations were available for 192 dogs during T1 and 37 dogs during T2. The median cumulative dose of HES was 86 mL/kg (range, 12-336 mL/kg). No difference was detected between the groups for age, gender, body weight, and length of hospitalization. Outcome was significantly different between the HES (66% survived) and the CRYS (87% survived) groups (P = 0.014). No significant difference was detected between groups for creatinine concentrations at T0, T1, T2, T1max%, or T2max%. No significant difference was detected between the groups for T1max% creatinine in dogs subclassified as having systemic inflammatory response syndrome or sepsis. CONCLUSIONS HES administration in this canine population did not result in increased creatinine concentrations compared to administration of CRYSs. Further studies are needed to establish the safety of HES in critically ill dogs.

Evaluation of the benefit of emergency vaccination in a foot-and-mouth disease free country with low livestock density

Foot-and-mouth disease (FMD) is highly contagious and one of the most economically devastating diseases of cloven-hoofed animals. Scientific-based preparedness about how to best control the disease in a previously FMD-free country is therefore essential for veterinary services. The present study used a spatial, stochastic epidemic simulation model to compare the effectiveness of emergency vaccination with conventional (non-vaccination) control measures in Switzerland, a low-livestock density country. Model results revealed that emergency vaccination with a radius of 3 km or 10 km around infected premises (IP) did not significantly reduce either the cumulative herd incidence or epidemic duration if started in a small epidemic situation where the number of IPs is still low. However, in a situation where the epidemic has become extensive, both the cumulative herd incidence and epidemic duration are reduced significantly if vaccination were implemented with a radius of 10 km around IPs. The effect of different levels of conventional strategy measures was also explored for the non-vaccination strategy. It was found that a lower compliance level of farmers for movement restrictions and delayed culling of IPs significantly increased both the cumulative IP incidence and epidemic duration. Contingency management should therefore focus mainly on improving conventional strategies, by increasing disease awareness and communication with stakeholders and preparedness of culling teams in countries with a livestock structure similar to Switzerland; however, emergency vaccination should be considered if there are reasons to believe that the epidemic may become extensive, such as when disease detection has been delayed and many IPs are discovered at the beginning of the epidemic.

Evidence for Emergency Vaccination Having Played a Crucial Role to Control the 1965/66 Foot-and-Mouth Disease Outbreak in Switzerland.

Foot-and-mouth disease (FMD) is a highly contagious disease that caused several large outbreaks in Europe in the last century. The last important outbreak in Switzerland took place in 1965/66 and affected more than 900 premises and more than 50,000 animals were slaughtered. Large-scale emergency vaccination of the cattle and pig population has been applied to control the epidemic. In recent years, many studies have used infectious disease models to assess the impact of different disease control measures, including models developed for diseases exotic for the specific region of interest. Often, the absence of real outbreak data makes a validation of such models impossible. This study aimed to evaluate whether a spatial, stochastic simulation model (the Davis Animal Disease Simulation model) can predict the course of a Swiss FMD epidemic based on the available historic input data on population structure, contact rates, epidemiology of the virus, and quality of the vaccine. In addition, the potential outcome of the 1965/66 FMD epidemic without application of vaccination was investigated. Comparing the model outcomes to reality, only the largest 10% of the simulated outbreaks approximated the number of animals being culled. However, the simulation model highly overestimated the number of culled premises. While the outbreak duration could not be well reproduced by the model compared to the 1965/66 epidemic, it was able to accurately estimate the size of the area infected. Without application of vaccination, the model predicted a much higher mean number of culled animals than with vaccination, demonstrating that vaccination was likely crucial in disease control for the Swiss FMD outbreak in 1965/66. The study demonstrated the feasibility to analyze historical outbreak data with modern analytical tools. However, it also confirmed that predicted epidemics from a most carefully parameterized model cannot integrate all eventualities of a real epidemic. Therefore, decision makers need to be aware that infectious disease models are useful tools to support the decision-making process but their results are not equal valuable as real observations and should always be interpreted with caution.

Prehospital ultrasound in emergency medicine: incidence, feasibility, indications and diagnoses

Sonography is an established diagnostic procedure in hospitals, but is not routinely used in prehospital emergency medicine. Several studies have addressed the use of ultrasound during helicopter flights and in emergency rooms, few in prehospital settings, but most focused on abdominal blunt trauma. Several case reports describe crucial decisions distinguished by ultrasound.