Current techniques in peritoneal dialysis

Urinary Tract Trauma in Cats: Stabilisation, Diagnosis and Management

PRACTICAL RELEVANCE

Traumatic injury of the urinary tract may be caused by external accidental trauma or due to iatrogenic injury (typically as a result of catheterisation procedures). Thorough patient assessment and careful attention to patient stabilisation are essential, with diagnosis and surgical repair delayed until the patient is stable, if necessary. Treatment depends on the location and severity of the trauma. If diagnosed and treated promptly, the chance of survival of a patient without other concurrent injuries is good.

CLINICAL CHALLENGES

Following accidental trauma, at the initial presentation urinary tract injury can be overshadowed by other injuries, but if left undiagnosed or untreated it can lead to serious morbidity and potentially mortality. Many of the surgical techniques described for management of urinary tract trauma can be associated with complications, and so comprehensive communication with the owners is necessary.

PATIENT GROUP

The main population affected by urinary tract trauma is young, adult male cats, owing to their roaming behaviour, as well as their anatomy and the resulting increased risk of urethral obstruction and its associated management.

AIMS

This article aims to serve as a guide to all veterinarians who treat cats for the diagnosis and management of urinary tract trauma in cats.

EVIDENCE BASE

This review summarises the current knowledge available from a number of original articles and textbook chapters in the literature that cover all aspects of feline urinary tract trauma, and is supported by the authors' own clinical experience.

Applicability of the drainage effectiveness of Blake drains and Tenckhoff catheters in the peritoneal dialysis of healthy rabbits (Oryctolagus cuniculus)

OBJECTIVE

To compare the efficacy of dialysate drainage between Tenckhoff (TC) catheter and Blake (BL) in peritoneal dialysis (PD) in healthy rabbits.

DESIGN

Prospective experimental study.

SETTING

University Teaching Hospital and University research laboratory.

ANIMALS

Twenty healthy, male, New Zealand rabbits.

INTERVENTIONS

PD via the TC catheter and the BL abdominal drain was compared during 3 consecutive days of dialysis delivery.

MEASUREMENTS AND MAIN RESULTS

One session of PD was performed per day for 3 consecutive days (S1: first session, S2: second session, S3: third session) and each session included 4 cycles of infusion, dwell of dialysate in the abdomen, and drainage. Data collection included daily urea, creatinine, alanine aminotransferase, albumin, and potassium, in addition to hematological parameters (eg, RBC, HCT, hemoglobin, WBC, and platelet count). Statistical analysis using a mixed linear model with multiple comparisons was performed. The BL drain resulted in an increase in volume drained (ml/kg) when compared to TC catheter on S2 (third and fourth cycles) and S3 (first and second cycles).

CONCLUSIONS

The BL drain proved to be superior to the TC catheter, being capable of draining a larger volume of dialysate during the drainage processes in the peritoneal PD of healthy rabbits. The TC catheter had major complications with regard to fluid retention in the abdomen, representing reduced drainage efficiency, while the BL drain showed a greater tendency for the peritoneal fluid to leak.

Successful resolution of urothorax secondary to non-traumatic uroabdomen in a cat managed with peritoneal dialysis as a bridge to surgery

Case summary

A 9-year-old neutered male domestic shorthair cat was presented for evaluation of severe hemodynamic collapse and suspected lower urinary tract disease. On admission, severe metabolic acidosis, hyperkalemia and azotemia, and electrocardiographic findings consistent with cardiotoxicity were identified. The diagnosis of uroabdomen was made based on abdominal fluid to plasma concentration ratios of creatinine and potassium. A central line catheter was placed percutaneously into the abdomen for peritoneal drainage and used for peritoneal dialysis as a bridge to surgery. Retrograde contrast cystography confirmed rupture of the urinary bladder. Point-of-care ultrasound of the chest postoperatively revealed the presence of mild pleural effusion. Echocardiography was then performed showing no evidence of cardiac disease. Pleural fluid analysis revealed a transudate with a creatinine ratio of 2.38 ([Creatinine]_{pleural fluid}/[Creatinine]_plasma), consistent with the diagnosis of urothorax. The cat recovered uneventfully from surgery and was monitored for signs of respiratory distress during the rest of its stay in hospital. The cat was discharged 4 days later and the pleural effusion resolved without further medical intervention.

Relevance and novel information

There is limited information on the causes of urothorax and uroabdomen management of feline patients. Pleural effusion is a complication observed in critically ill cats secondary to fluid overload, underlying cardiomyopathy, primary thoracic pathology or a combination of these. To our knowledge, this is the first report of urothorax in a cat secondary to non-traumatic uroabdomen. Careful monitoring of respiratory signs consistent with pleural space disease is recommended in cases of uroabdomen.

Establishment of a model for equine small intestinal disease: effects of extracorporeal blood perfusion of equine ileum on metabolic variables and histological morphology - an experimental ex vivo study

BACKGROUND

In horses a number of small intestinal diseases is potentially life threatening. Among them are Equine Grass Sickness (EGS), which is characterised by enteric neurodegeneration of unknown aetiology, as well as reperfusion injury of ischaemic intestine (I/R), and post-operative ileus (POI), common after colic surgery. The perfusion of isolated organs is successfully used to minimize animal testing for the study of pathophysiology in other scenarios. However, extracorporeal perfusion of equine ileum sourced from horses slaughtered for meat production has not yet been described. Therefore the present study evaluated the potential of such a model for the investigation of small intestinal diseases in an ex vivo and cost-efficient system avoiding experiments in live animals.

RESULT

Nine ileum specimens were sourced from horses aged 1-10 years after routine slaughter at a commercial abattoir. Ileum perfusion with oxygenated autologous blood and plasma was successfully performed for 4 h in a warm isotonic bath (37.0-37.5 °C). Ileum specimens had good motility and overall pink to red mucosa throughout the experiment; blood parameters indicated good tissue vitality: 82 ± 34 mmHg mean arterial partial pressure of oxygen (pO₂) compared to 50 ± 17 mmHg mean venous pO_2, 48 ± 10 mmHg mean arterial partial pressure of carbon dioxide (pCO₂) compared to 66 ± 7 mmHg venous pCO₂ and 9.8 ± 2.8 mmol/L mean arterial lactate compared to 11.6 ± 2.7 mmol/L venous lactate. There was a mild increase in ileum mass reaching 105 ± 7.5% of the pre-perfusion mass after 4 hours. Histology of haematoxylin and eosin stained biopsy samples taken at the end of perfusion showed on average 99% (±1%) histologically normal neurons in the submucosal plexus and 76.1% (±23.9%) histologically normal neurons in the myenteric plexus and were not significantly different to control biopsies.

CONCLUSION

Extracorporeal, normothermic perfusion of equine ileum over 4 h using autologous oxygenated blood/plasma perfusate showed potential as experimental model to test whether haematogenous or intestinal exposure to neurotoxins suspected in the pathogenesis of EGS can induce neuronal damage typical for EGS. Also, this model may allow investigations into the effect of pharmaceuticals on I/R injury, as well as into the pathogenesis of equine POI.

Severe hyperkalemia presenting with wide-complex tachycardia in a puppy with acute kidney injury secondary to leptospirosis

OBJECTIVE

To describe a case of hyperkalemia coinciding with wide-complex tachycardia (WCT) in a dog with acute kidney injury secondary to leptospirosis infection.

CASE SUMMARY

An 11-week-old Golden Retriever-Standard Poodle cross puppy was referred for acute kidney injury and hepatopathy. WCT coinciding with marked hyperkalemia was identified on presentation. Tachycardia persisted until resolution of hyperkalemia.

NEW OR UNIQUE INFORMATION PROVIDED

To our knowledge, this is the first report of severe hyperkalemia presenting with WCT in a dog. Hyperkalemia should be considered a differential for WCT in dogs.

ISFM Consensus Guidelines on the Diagnosis and Management of Feline Chronic Kidney Disease

PRACTICAL RELEVANCE

Chronic kidney disease (CKD) is one of the most commonly diagnosed diseases in older cats. In most cats, CKD is also a progressive disease and can be accompanied by a wide range of clinical and clinicopathological changes. These ISFM Consensus Guidelines have been developed by an independent panel of clinicians and academics to provide practical advice on the diagnosis and management of this complex disease.

CLINICAL CHALLENGES

Although CKD is a common clinical problem in cats, the manifestations of disease vary between individuals. Thus there is a need for careful and repeat evaluation of cats with CKD and adjustment of therapy according to individual needs. In addition to addressing problems arising from CKD and improving quality of life (QoL) for the patient, therapy may also target slowing the underlying progression of disease and hence prolonging life. While maintaining QoL is of paramount importance in our patients, this can be challenging when multiple therapies are indicated. In some cases it is necessary to prioritise therapy, given an understanding of what is likely to most benefit the individual patient.

EVIDENCE BASE

In preparing these Guidelines, the Panel has carefully reviewed the existing published literature, and has also graded the quality of evidence for different interventions to help to provide practical recommendations on the therapeutic options for feline CKD. This is a field of veterinary medicine that has benefited from some excellent published clinical research and further research findings will undoubtedly modify the recommendations contained in these Guidelines in the future.