Retrospective evaluation of the prevalence, risk factors, management, outcome, and necropsy findings of acute lung injury and acute respiratory distress syndrome in dogs and cats: 29 cases (2011-2013)

Retrospective study of 540 cats with respiratory diseases in Japan (2003-2020)

BACKGROUND

Few epidemiological studies on respiratory medicine and the relationship between clinical signs and various respiratory diseases in cats have been reported.

OBJECTIVES

This retrospective study aimed to investigate the prevalence and breed predisposition to feline respiratory diseases in Japan and determine the association between clinical signs, duration and type of respiratory diseases.

METHODS

The medical records of cats with feline respiratory diseases were examined to obtain information on age, sex, breed, final diagnosis, clinical signs and duration. The odds ratios (ORs) and 95% confidence intervals were calculated to evaluate breed predispositions. Mann-Whitney U, Kruskal-Wallis and Dunn's tests were used to assess the duration of clinical signs.

RESULTS

This study included 540 cats with 615 respiratory diagnoses. The American Shorthair breed was predisposed to bronchopneumonia (BP; OR: 5.0) and pulmonary tumour (PT; OR: 3.6), while the Russian Blue breed exhibited a predisposition to inflammatory lower airway diseases (OR: 3.4), BP (OR: 6.1) and interstitial lung diseases (OR: 11.1). Similarly, the Scottish Fold breed displayed predisposition to PTs (OR: 5.8). The duration of clinical signs among nasal diseases, nasopharyngeal diseases and lower tracheal/bronchial and pulmonary diseases differed significantly (p = 0.001, p = 0.012, p < 0.0001, respectively).

CONCLUSIONS

The results suggest that some popular breeds in Japan are predisposed to feline respiratory diseases, especially the American Shorthair, Russian Blue and Scottish Fold breeds. The characteristics of occurrence, clinical signs and duration of each disease will aid in diagnosing, treating, preventing and elucidating the pathophysiology of feline respiratory disease.

Lung pathology of natural Babesia rossi infection in dogs

A proportion of Babesia rossi infections in dogs are classified as complicated and one of the most lethal complications is acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Most dogs that die succumb within 24 hours of presentation. The pulmonary pathology caused by B. rossi in dogs has not been described. The aim of this study was to provide a thorough macroscopic, histological and immunohistochemical description of the lung changes seen in dogs naturally infected with B. rossi that succumbed to the infection. Death was invariably accompanied by alveolar oedema. Histopathology showed acute interstitial pneumonia characterised by alveolar oedema and haemorrhages, with increased numbers of mononuclear leucocytes in alveolar walls and lumens. Intra-alveolar polymerised fibrin aggregates were observed in just over half the infected cases. Immunohistochemistry showed increased numbers of MAC387- and CD204-reactive monocyte-macrophages in alveolar walls and lumens, and increased CD3-reactive T-lymphocytes in alveolar walls, compared with controls. These histological features overlap to some extent (but far from perfectly) with the histological pattern of lung injury referred to as the exudative stage of diffuse alveolar damage (DAD) as is quite commonly reported in ALI/ARDS.

Noncardiogenic pulmonary edema in small animals

OBJECTIVE

To review various types of noncardiogenic pulmonary edema (NCPE) in cats and dogs.

ETIOLOGY

NCPE is an abnormal fluid accumulation in the lung interstitium or alveoli that is not caused by cardiogenic causes or fluid overload. It can be due to changes in vascular permeability, hydrostatic pressure in the pulmonary vasculature, or a combination thereof. Possible causes include inflammatory states within the lung or in remote tissues (acute respiratory distress syndrome [ARDS]), airway obstruction (post-obstructive pulmonary edema), neurologic disease such as head trauma or seizures (neurogenic pulmonary edema), electrocution, after re-expansion of a collapsed lung or after drowning.

DIAGNOSIS

Diagnosis of NCPE is generally based on history, physical examination, and diagnostic imaging. Radiographic findings suggestive of NCPE are interstitial to alveolar pulmonary opacities in the absence of signs of left-sided congestive heart failure or fluid overload such as cardiomegaly or congested pulmonary veins. Computed tomography and edema fluid analysis may aid in the diagnosis, while some forms of NCPE require additional findings to reach a diagnosis.

THERAPY

The goal of therapy for all types of NCPE is to preserve tissue oxygenation and reduce the work of breathing. This may be achieved by removing the inciting cause (eg, airway obstruction) and cage rest in mild cases and supplemental oxygen in moderate cases and may require mechanical ventilation in severe cases.

PROGNOSIS

Prognosis is generally good for most causes of veterinary NCPE except for ARDS, although data are scarce for some etiologies of NCPE.

Retrospective evaluation of negative-pressure pulmonary edema in dogs (2006-2018): 35 cases

OBJECTIVE

To describe the clinical characteristics and outcomes in a population of dogs with negative-pressure pulmonary edema (NPPE) and to identify the main causes of the disease. To evaluate any associations with morbidity and mortality.

DESIGN

Retrospective study.

SETTING

Three university teaching hospitals and 2 private referral centers in the United Kingdom.

ANIMALS

Thirty-five client-owned dogs presented with NPPE.

INTERVENTIONS

None MEASUREMENTS AND MAIN RESULTS: Data collected included patient characteristics, clinical history, clinicopathological abnormalities, radiographic features, treatments, and outcomes. The median age was 4 months (range 2-90) and median weight was 7.1 kg (range 1.7-37.2). There were many causes of NPPE including leash tugs, near hanging, accidental choking, anatomical obstruction to airflow, and purposeful airway obstruction by people. The most common cause of NPPE was accidental choking (40% of cases). Dogs with an anatomical obstruction were older than 24 months. Hypoxemia with an increased alveolar-arterial gradient was common on presentation. The majority of thoracic radiographs (65.7%) showed an alveolar or interstitial pattern in the caudodorsal area as previously described in the literature. Oxygen therapy was administered to 33 (94.3%) dogs. Furosemide was administered to 18 (51.4%) dogs. The median length of hospitalization was 2 days (range 0-14). Twenty-eight (80%) dogs survived to discharge. Seven dogs were mechanically ventilated and only 2 of them (28.6%) survived to discharge. The requirement for mechanical ventilation was the only parameter associated with mortality (P < 0.001).

CONCLUSIONS

Most cases of NPPE occur in juvenile dogs. Different incidents associated with upper airway obstruction can produce an episode of NPPE. Choking on food or toys and near hanging have not been previously described in the veterinary literature as inciting causes of NPPE. The overall prognosis is good.

A Review of High Flow Nasal Cannula Oxygen Therapy in Human and Veterinary Medicine

Respiratory distress is a common ailment in small animal medicine. Oxygen supplementation is a mainstay of initial therapy. High Flow Nasal Cannula Oxygen Therapy (HFNCOT) has become increasingly popular as a treatment modality in human medicine, and more recently in canine patients. These devices deliver high flow rates of heated and humidified oxygen at an adjustable fraction of inspired oxygen (FiO₂). This article reviews current literature in human patients on HFNCOT as well as studies that have evaluated its use in veterinary patients. A discussion of the respiratory physiology that is associated with respiratory distress, in addition to an overview of currently available oxygen supplementation modalities is provided. The physiologic benefits of HFNCOT are explained, as are technical aspects associated with its use. Recommendations on initial settings, maintenance therapy, and weaning are also described.

Respiratory Emergencies

Respiratory distress is commonly seen in dogs and cats presenting to the emergency room. Rapid identification of respiratory difficulty with strategic stabilization and diagnostic efforts are warranted to maximize patient outcome. This article focuses on the relevant anatomy and physiology of the respiratory system and the clinical recognition, stabilization, and initial diagnostic planning for small animal patients that present for respiratory emergencies.

Pulmonary complications in dogs with acute presentation of pancreatitis

Background

In humans, respiratory complications in patients with acute pancreatitis (AP) are a common life-threatening comorbidity. Since possible lung impairment has not been individually evaluated in canine AP, the aims of the present study were to: (1) describe the prevalence, types and severity of pulmonary complications in dogs with acute presentation of AP, and (2) evaluate their association with mortality. AP diagnosis was based on compatible clinical and laboratory parameters, abnormal canine pancreatic-lipase test, and positive abdominal ultrasound within 48 h from admission. The canine acute pancreatitis severity score (CAPS) was calculated for each dog at admission. Arterial blood gas analysis and thoracic radiography were performed at admission. Thoracic radiography was classified on the basis of pulmonary pattern (normal, interstitial or alveolar) and a modified lung injury score (mLIS) was applied to the ventrodorsal projections for each dog. VetALI/VetARDS were diagnosed using current veterinary consensus. Dogs were divided into non-survivors or survivors (hospital discharge). Clinical, radiological and blood gas parameters collected at presentation were compared between survivors and non-survivors and associated with mortality.

Results

This prospective cohort study included twenty-six client-owned dogs with AP. Twelve out of twenty-six dogs (46%) died or were euthanized. At admission, thirteen dogs showed respiratory distress at physical examination, which was associated with death (P < 0.001). Radiographic abnormalities were found in twenty-one dogs: alveolar (n = 11) and interstitial pattern (n = 10). Radiographic alterations and mLIS score were both associated with death (P = 0.02 and P = 0.0023). The results of the arterial blood-gas evaluation showed that non-survivors had lower PaCO₂ and HCO₃⁻ levels, and higher A-a gradient than survivors (P = 0.0014, P = 0.019 and P = 0.004, respectively). Specifically, three dogs had aspiration pneumonia, and VetALI was diagnosed in nine dogs (34.6%), and no dogs met the criteria for VetARDS. The presence of VetALI was associated with mortality (P < 0.001).

Conclusions

As with humans, possible lung impairments, such as VetALI, should be investigated in dogs with acute presentation of pancreatitis.

Prognostic markers and assessment of a previously published clinical severity index in 109 hospitalised dogs with acute presentation of pancreatitis

BACKGROUND

Acute pancreatitis (AP) is common in dogs. Nevertheless, validated clinical severity index (CSI) scoring systems to assess severity and guide treatment in current, large-scale studies are unavailable.

METHODS

This is a retrospective study including 109 dogs. Pancreatitis was diagnosed based on clinical signs, abdominal sonographic evidence, positive pancreatic lipase assays and experts' assessment consensus.

RESULTS

The survival rate was 75 per cent (82 dogs). Azotaemia and presence of local complications (ie, ascites) and secondary complications (ie, acute kidney injury and acute respiratory distress syndrome) were significantly associated with death. In agreement with the previously published CSI, respiratory anomalies were significantly associated with death. However, in disagreement with that study, high scores in the kidney and local abdominal complication categories and the sum of scores of all nine categories, but not high gastrointestinal category score, were also significantly associated with death. A final CSI score of at least 4 was associated with death.

CONCLUSIONS

This study has validated a nine-category CSI, proven a useful assessment tool in dogs with AP. Several previously reported and novel prognostic markers were assessed.

Prognostic Significance of Organ Dysfunction in Cats With Polytrauma

Polytrauma is a common emergency condition in small animals and is frequently associated with higher morbidity and mortality rates compared to minor trauma. Multiple Organ Dysfunction Syndrome (MODS) is a major complication of extensive traumatic injury, carrying a high risk of death despite intensive care treatment. Little is known about the prevalence and the prognostic impact of MODS in feline polytrauma. The current study aimed to prospectively evaluate the occurrence and the prognostic significance of organ dysfunction at admission in a population of polytraumatized cats. Cats with polytrauma requiring intensive care unit hospitalization were included and categorized according to outcome (survivors/non-survivors). Clinical and clinicopathological data, including scores of disease severity [Animal Trauma Triage Score (ATTS), APPLE_fast, and APPLE_full], selected organ dysfunction and presence of MODS were evaluated upon admission, and analyzed with respect to mortality. Non-parametric statistics was performed and P < 0.05 was considered significant. Thirty-eight cats met the inclusion criteria: 8/38 (21%) had penetrating trauma, while 30/38 (79%) had blunt trauma. The overall in-hospital mortality was 37% (14/38). Cats with evidence of MODS upon admission had significantly higher frequency of death compared to cats without MODS (9/14 vs. 2/24 P = 0.0004). Hemostatic dysfunction, respiratory dysfunction, and MODS upon admission were significantly associated with mortality in the univariate logistic regression analysis (P = 0.005, P = 0.001, P = 0.001, respectively). The values of APPLE_fast, APPLE_full, and ATTS were independently associated with a higher risk of death and positively correlated with the number of dysfunctional organs (P = 0.025, P = 0.004, P = 0.003, r = 0.57, P = 0.0002; r = 0.59, P = 0.0001; r = 0.55, P = 0.0003, respectively). Multiple Organ Dysfunction Syndrome is a common complication of feline polytrauma and its development is associated with increased disease severity and worse outcomes. The presence of hemostatic dysfunction and respiratory dysfunction upon admission is associated with a higher risk of death. The ATTS and the APPLE scores are useful prognostic tools for the assessment of cats with polytrauma.

Interstitial lung diseases in dogs and cats part I: The idiopathic interstitial pneumonias

Interstitial lung diseases (ILDs), also called diffuse parenchymal lung diseases, are a large heterogenous group of non-infectious, non-neoplastic disorders characterized by varied patterns of inflammation and fibrosis (Travis et al., 2002). In humans, accurate classification of interstitial lung diseases (ILDs) requires multidisciplinary collaboration between clinicians, radiologists and pathologists. The same is likely to be true for canine and feline ILDs; however, this collaborative approach is rarely taken, leading to a paucity of knowledge of ILDs in small animal species. A proposed classification scheme of canine and feline ILDs, modified from a human classification scheme, consists of three major groups: idiopathic interstitial pneumonias (IIPs), ILDs secondary to known causes, and miscellaneous ILDs (Travis et al., 2002). The focus of this review is on the IIPs in dogs and cats. A framework of what is known about the major IIPs in humans will be used to draw parallels when relevant to the canine and feline species. Differences will also be highlighted. When available from the veterinary literature, clinical presentation, diagnostic results, treatment and/or prognosis will be reported. The review underscores that to advance in our knowledge of veterinary IIPs and other ILDs, clinicopathologic features, advanced imaging and histopathology must be carefully integrated and larger groups of animals studied.

Interstitial lung diseases in dogs and cats part II: Known cause and other discrete forms

In addition to idiopathic interstitial pneumonias, interstitial lung diseases (ILDs) can occur secondary to known causes or be classified as discrete syndromes. Also known as diffuse parenchymal lung diseases, the ILDs represent a heterogenous group of non-infectious, non-neoplastic disorders characterized by varied patterns of inflammation and fibrosis. Characteristically associated with the true interstitium (i.e. the anatomic space lined by alveolar epithelial cells and capillary endothelial cells and the loose-binding connective tissue), it is important to understand ILDs are associated with pathology of the distal lung parenchyma and thus lesions can be bronchiolocentric or resemble alveolar filling disorders. Injury to the distal lung can occur via inhalation or hematogenous routes. This review will build on a proposed classification scheme adapted from human medicine to describe known cause and discrete forms of ILDs in dogs and cats.

Multiorgan dysfunction syndrome in feline sepsis: prevalence and prognostic implication

OBJECTIVES

The current study was designed to evaluate the prevalence and prognostic significance of multiorgan dysfunction syndrome (MODS) in cats with sepsis.

METHODS

Cats hospitalised in the intensive care unit of a veterinary university hospital with a diagnosis of sepsis were prospectively enrolled and divided according to disease severity and outcome (survivors; non-survivors). The feline acute patient physiological and laboratory evaluation (APPLE) scores were calculated upon admission, as previously described. Specific criteria to identify selected organ dysfunction (hepatic, renal, respiratory, cardiocirculatory, haemostatic) were adapted from the available human and veterinary literature, and evaluated at baseline and at the end of hospital stay. MODS was defined as the presence of at least two dysfunctional organs simultaneously. Non-parametric statistics were used for comparisons. Univariate and multivariate regression analyses to evaluate significant risk factors for death were carried out. Correlations between variables were assessed by the Spearman's rank correlation coefficient. Significance was set at P <0.05.

RESULTS

A total of 43 cats with heterogeneous sources of sepsis were included. MODS was identified in 25/43 cats upon admission and in 32/43 cats at the end of hospital stay. Regression analyses showed a significantly elevated odds ratio for mortality for the presence of MODS, renal and cardiovascular dysfunction upon admission, as well as for the number of dysfunctional organs. The latter was the only variable retained by the model from the multivariate binary logistic regression analysis. Significant correlations were documented between the number of dysfunctional organs and the APPLE scores.

CONCLUSIONS AND RELEVANCE

MODS is a frequent complication of feline sepsis, and is associated with worse outcomes. In particular, renal and cardiovascular dysfunction significantly increase the odds for death. Hence, systematic screening for organ dysfunction is advocated in cats with sepsis.