Critical care monitoring

Cardiology in Rodents, Rabbits, and Small Exotic Mammals-Diagnostic Workup

The incidence of cardiac diseases in pet rabbits and rodents increased over the past decade as these species live longer and diagnostics methods are more precise to diagnose heart diseases even in small-sized animals. The article summarizes diagnostics of cardiac diseases in selected exotic companion mammals, particularly in rabbits, guinea pigs, chinchillas, and rats. The emphasis of the paper is given on clinical examination, thoracic radiography, electrocardiography, and echocardiography.

Heart Disease in Pet Birds - Diagnostic Options

Cardiovascular diseases are common in pet birds. Diagnosis is often made postmortem only. In any case, suspicious for cardiac disease, a full diagnostic work up should be applied. First indications are given by the anamnestic data. Relative predisposition to cardiovascular diseases is associated with the species, breed, age, gender, lifestyle, and diet. Clinical signs and examination can reveal further indications of cardiovascular diseases, but may be unspecific or even without any pathologic finding. Diagnostic imaging, at least radiography, and echocardiography are always recommended. Advanced imaging methods, especially angiocardiography, can be valuable but is also more invasive and expensive.

Use of Amlodipine in Psittacine Birds: 5 Cases (2010-2018)

Amlodipine is a calcium channel blocker shown to be effective in lowering blood pressure with minimal adverse effects in mammals. To provide a retrospective evaluation of amlodipine use in psittacine birds, medical records were reviewed for all avian patients prescribed amlodipine for treatment for the presumptive diagnosis of hypertension, based on clinical signs and indirect blood pressure measurements. Five birds were treated with amlodipine between 2010 and 2018. The median age was 33 years (range, 22-37 years) and 3/5 birds presented for ataxia or seizures. The median indirect systolic blood pressure at diagnosis was 243 mm Hg (range, 200-275 mm Hg). In 3/5 birds, amlodipine was the only drug prescribed, whereas, in 2/5 birds, enalapril was also prescribed in addition to amlodipine. In addition to the prescription of enalapril, blood pressure measurements were obtained indirectly, which are variables to be considered in this report. The initial median dose of amlodipine prescribed was 0.4 mg/kg (range, 0.1-0.4 mg/kg) PO q24h. In 3/5 birds, amlodipine administration was increased either in dose or frequency. Median follow-up time was 25 months (range, 2-55 months) after the initiation of amlodipine treatment. Owners in all 5 cases reported improvement of clinical signs by a median time of 2 months (range, 1-15 months). Three of 5 birds (60%) demonstrated a decreasing trend in blood pressure during the first 6 months after treatment with amlodipine was started (average, ≥20% decrease). Prospective, controlled studies are needed to investigate the efficacy of amlodipine in psittacine birds.

Basic Approach to Veterinary Care of Ferrets

The approach to preventive medicine and basic veterinary care in ferrets is very similar to that used in dogs and cats. Special equipment needs are minimal, and pet ferrets can be easily incorporated into a general small animal practice. This chapter describes the unique aspects of handling, restraint, and clinical and treatment techniques used in ferrets.

Comparison of Dexmedetomidine-Ketamine-Midazolam and Isoflurane for Anesthesia of Black-tailed Prairie Dogs (Cynomys ludovicianus)

Few studies evaluate anesthesia in black-tailed prairie dogs (Cynomys ludovicianus). Isoflurane inhalant anesthesia is used in this species most commonly, but injectable protocols are poorly described. Here we compared the physiologic effects, including anesthetic depth, vital signs, and hematologic changes, of anesthetic protocols using isoflurane or a combination of dexmedetomidine, ketamine, and midazolam in black-tailed prairie dogs. In a randomized, complete crossover study design, intact male black-tailed prairie dogs (n = 9; age, 6 mo) were anesthetized by using a combination of dexmedetomidine (0.25 mg/kg IM), ketamine (40 mg/kg IM), and midazolam (1.5 mg/kg IM). For reversal, atipamezole (0.15 mg/kg) and flumazenil (0.05 mg/kg) were administered 45 min after induction. For comparison, isoflurane was administered at 5% in 100% oxygen at 5 L/min in an anesthetic induction chamber, followed by maintenance isoflurane 2% in 2 L/min oxygen through a tight-fitting facemask for 45 min. Induction and recovery time, respiratory rate, heart rate, body temperature, SpO₂, indirect blood pressure, and reflexes were monitored every 5 min during the anesthetic period. Blood samples for venous blood gases, PCV, and refractometric total protein were obtained from the cranial vena cava at 5 min and 45 min. Both protocols appeared to achieve safe and effective anesthesia. Except for blood pressure, all vital signs differed between the 2 treatments. Isoflurane anesthesia resulted in a slightly longer induction and lower respiratory rate and body temperature but increased likelihood of absent reflexes. DKM anesthesia resulted in a faster induction and less hypothermia but also prolonged recovery and lower heart rate and SpO₂ readings. These findings suggest that isoflurane provides a more stable and consistent anesthetic plane, whereas dexmedetomidine-ketamine-midazolam anesthesia may be an effective alternative for short procedures that require fast induction and limited analgesia.

Chylous ascites associated with abdominal trauma and intestinal resection-anastomosis in a pet ferret (Mustela putorius furo)

CASE DESCRIPTION A 10-week-old 0.73-kg (1.6-lb) castrated male domestic ferret (Mustela putorius furo) was referred for exploratory laparotomy because of pneumoperitoneum and possible septic peritonitis after being bitten by the owner's dog. CLINICAL FINDINGS Abdominal exploration revealed a large laceration of the duodenum, tears of the jejunal mesentery, and 2 small tears in the abdominal wall. Chylous abdominal effusion developed 48 hours after surgery. TREATMENT AND OUTCOME Postoperative care included supportive treatment, analgesia, and antimicrobials. An abdominal drain was placed during the laparotomy and enabled monitoring of abdominal fluid production. Enteral feeding was provided through an esophagostomy tube. The chylous fluid production rapidly decreased after treatment with octreotide was initiated, and the ferret improved. Chyloabdomen resolved after 8 days of hospitalization and medical treatment. CLINICAL RELEVANCE Findings suggested that chylous ascites can potentially develop secondary to blunt abdominal trauma in ferrets. In this ferret, chyloabdomen was successfully treated with octreotide administration and abdominal drainage.

Assessment and Care of the Critically Ill Rabbit

Rabbits have the ability to hide their signs and often present in a state of decompensatory shock. Handling can increase susceptibility to stress-induced cardiomyopathy and specific hemodynamic changes. Careful monitoring with a specific reference range is important to detect early decompensation, change the therapeutic plan in a timely manner, and assess prognostic indicators. Fluid requirements are higher in rabbits than in other small domestic mammals and can be corrected both enterally and parenterally. Critical care in rabbits can be extrapolated to many hindgut fermenters, but a specific reference range and dosage regimen need to be determined.

Point-of-Care Blood Gases, Electrolytes, Chemistries, Hemoglobin, and Hematocrit Measurement in Venous Samples from Pet Rabbits

Point-of-care testing is an attractive option in rabbit medicine, because it permits rapid analysis of a panel of electrolytes, chemistries, blood gases, hemoglobin, and hematocrit, requiring only 65 μL of blood. The purpose of this study was to evaluate the performance of a portable clinical analyzer for measurement of pH, partial pressure of CO2, Na, chloride, potassium, blood urea nitrogen, glucose, hematocrit, and hemoglobin in healthy and diseased rabbits. Blood samples obtained from 30 pet rabbits were analyzed immediately after collection by the portable clinical analyzer (PCA) and immediately thereafter (time <20 sec) by a reference analyzer. Bland-Altman plots and Passing-Bablok regression analysis were used to compare the results. Limits of agreement were wide for all the variables studied, with the exception of pH. Most variables presented significant proportional and/or constant bias. The current study provides sufficient evidence that the PCA presents reliability for pH, although its low agreement with a reference analyzer for the other variables does not support their interchangeability. Limits of agreement provided for each variable allow researchers to evaluate if the PCA is reliable enough for their scope. To the authors’ knowledge, the present is the first report evaluating a PCA in the rabbit.

Successful cardiopulmonary resuscitation following cardiopulmonary arrest in a geriatric chinchilla

OBJECTIVE

To describe the successful application of CPR in a geriatric chinchilla employing basic and advanced life support measures during cardiopulmonary arrest (CPA).

CASE SUMMARY

A 13-year-old female intact chinchilla presented to a general and multispecialty referral hospital for a dental procedure. During recovery from anesthesia the patient suffered CPA and CPR was initiated. Noninvasive positive pressure mask ventilation was initiated and external chest compressions were performed. An 18-Ga needle was introduced into the medullary cavity of the right humerus as an intraosseous catheter and provided access for administration of drugs and fluids. After return of spontaneous circulation was noted mannitol was administered via the intraosseous catheter to alleviate suspected increased intracranial pressure. Clinical improvement was noted shortly after administration. Monitoring during the recovery period showed a normal sinus cardiac rhythm and a SpO₂ of 100% while on supplemental oxygen. Neurologic function continued to improve over the following hours. Oxygen therapy was provided via an oxygen cage, and administration of antimicirobials, gastrointestinal protectants, and nutritional supplementation were part of the post resuscitation care. Oxygen therapy was discontinued after 24 hours, during which time normal behaviors were observed and neurologic status was considered appropriate. The patient was discharged 48 hours after CPA.

NEW OR UNIQUE INFORMATION PROVIDED

Published reports from clinical practice on the outcomes of CPR for exotic small mammals are limited. This report details the successful outcome of the use of combined basic and advanced life support measures for the provision of CPR in a chinchilla. This report also highlights the utility of an intraosseous catheter for administration of drugs and fluids novel to this species during resuscitation and recovery. To the authors' knowledge this is the first published report of successful CPR following CPA in a geriatric chinchilla.

Respiratory system anatomy, physiology, and disease: Guinea pigs and chinchillas

Respiratory diseases are common in guinea pigs and chinchillas. There are multifactorial causes of respiratory involvement in these species of rodents, from infectious (bacterial, viral, and fungal) to neoplastic causes. Toxicoses and diseases affecting other systems may also induce respiratory signs. Knowledge of biology, including husbandry, nutritional requirements, and behavior, are important clues for the clinician to determine the role these issues may play in the development, progression, and prognosis of respiratory clinical cases in rodents. Current approaches in the diagnosis and therapy for respiratory disease in small mammals warrant more research concerning response-to-treatment reports.

Indirect blood pressure monitoring in small mammals

Direct blood pressure monitoring is the most accurate cardiovascular monitoring technique, but it is challenging in small mammals, as well as time-consuming and costly. Therefore, indirect blood pressure monitoring is most commonly used in clinic and laboratory settings. This column discusses indirect blood pressure monitoring in small mammals.