Inter-rater agreement and characterization of pleural line and subpleural fields in canine lung ultrasound: a comparative pilot study between high-frequency linear and curvilinear transducers using B- and M-mode ultrasonographic profiles

BACKGROUND

Lung ultrasound (LUS) is increasingly utilized in veterinary medicine to assess pulmonary conditions. However, the characterization of pleural line and subpleural fields using different ultrasound transducers, specifically high-frequency linear ultrasound transducers (HFLUT) and curvilinear transducers (CUT), remains underexplored in canine patients. This study aimed to evaluate inter-rater agreement in the characterization of pleural line and subpleural fields using B- and M-mode ultrasonography in dogs with and without respiratory distress.

RESULTS

Eighty-eight ultrasound clips from nine dogs were analyzed. HFLUT demonstrated strong inter-rater agreement in B-mode (κ = 0.89) and near-perfect agreement in M-mode (κ = 1.00) for pleural line homogeneity. In contrast, CUT showed minimal agreement in both B-mode (κ = 0.34) and M-mode (κ = 0.37). Homogeneous pleural lines were predominantly observed in control dogs or those with cardiogenic pulmonary edema (CPE), while non-homogeneous pleural lines were more common in dogs with non-cardiogenic alveolar-interstitial syndrome (NCAIS). Vertical subpleural fields identified in M-mode were associated with both CPE and NCAIS, whereas horizontal fields were more often observed in control dogs.

CONCLUSIONS

HFLUT offers superior inter-rater reliability for characterizing pleural and subpleural features in canine LUS compared to CUT, particularly in M-mode. These findings suggest HFLUT may enhance diagnostic accuracy for pulmonary conditions in dogs. Further studies are needed to explore the diagnostic potential of LUS in differentiating vertical artifact (e.g., B-lines) etiologies in veterinary patients.

Evaluation of B-lines with 2 point-of-care lung ultrasound protocols in cats with radiographically normal lungs

OBJECTIVE

To compare 2 point-of-care lung ultrasound (LUS) protocols for quantification of B-lines in cats without evidence of respiratory disease based on history, physical examination, and thoracic radiography.

DESIGN

Prospective observational study.

SETTING

Single center, veterinary teaching hospital.

ANIMALS

Fifty-seven cats without respiratory disease based on history, physical examination, and thoracic radiographs.

INTERVENTIONS

All cats had 2 point-of-care LUS protocols performed bilaterally: a regional protocol (veterinary bedside lung ultrasound evaluation [VetBLUE]) and a more comprehensive vertical sweeping (VS) protocol. The total number of B-lines per cat, number of sites with B-lines, and maximal number of B-lines at each site were recorded and compared.

MEASUREMENTS AND MAIN RESULTS

Ten cats (18%) had at least 1 B-line identified with VetBLUE, versus 29 (51%) with VS. Comparing protocols, VS had a statistically higher total number of B-lines per cat, higher number of sites with B-lines, and higher maximal number of B-lines per site. B-lines that were too numerous to count were identified at a single location in 1 cat with VetBLUE and 2 cats with VS. A maximum of 3 B-lines were identified at all other positive sites regardless of the protocol used. On average, it took 1.79 times longer to complete VS bilaterally compared to VetBLUE (median [interquartile range]: 140 [33] and 78 [14] s, respectively) (P = 0.001).

CONCLUSIONS

This study demonstrates it is not uncommon to identify a single or even multiple B-lines in 1 or several sites on LUS in cats deemed to be clinically free of respiratory pathology-essential knowledge when using LUS as a screening test and to monitor intrathoracic lesions. In cats asymptomatic for respiratory disease, VS generally identifies more B-lines than VetBLUE, likely because it assesses a larger lung surface area. The sonographic identification of B-lines should be interpreted considering the LUS protocol used, history, and other diagnostics to determine their clinical significance.

Echocardiographic caudal vena cava measurements in healthy cats and in cats with congestive heart failure and non-cardiac causes of cavitary effusions

BACKGROUND

Echocardiographic indices of the inferior vena cava have been associated with elevated right atrial pressures in humans.

HYPOTHESIS/OBJECTIVES

Describe caudal vena caval (CVC) sonographic dimensions in healthy cats compared to cats with cardiogenic cavitary effusion (CCE), cardiogenic pulmonary edema (CPE), or non-cardiac causes of cavitary effusion (NCE).

ANIMALS

30 healthy control cats and 52 client-owned cats with CCE, CPE, or NCE examined at two university hospitals.

METHODS

Sagittal 2-dimensional (2D) and M-mode CVC dimensions were acquired from the subxiphoid view. Caudal vena cava collapsibility index (CVC-CI) was calculated. Variables were compared between study groups using Kruskal-Wallis and Dunn's Bonferroni testing. Receiver operating characteristic curves were used to assess sensitivity and specificity for diagnostic categories.

RESULTS

Healthy cats had sagittal 2D and M-mode (median, interquartile range) CVC maximal dimensions of 2.4 mm (1.3-4.0) and 3.4 mm (1.5-4.9) and CVC-CI of 52% (45.2-61.8) and 55% (47.8-61.3), respectively. The CVC maximal dimensions in healthy controls were smaller than in cats with cavitary effusions or pulmonary edema (all P<0.05). CVC-CI was different between CCE and NCE (P<0.0001) with cutoffs of CVC-CI ≤38% (2D) or ≤29% (M-mode) being 90.5% and 85.7% sensitive, and 94.4% and 100% specific for diagnosis of CCE, respectively.

CONCLUSIONS AND CLINICAL IMPORTANCE

Caudal vena cava measurements are larger in cats with cavitary effusions and cats with CPE than healthy cats. In cats with cavitary effusion, decreased CVC-CI, ≤38% (2D) or ≤29% (M-mode), was helpful in distinguishing between cardiogenic and noncardiogenic etiology.

Integrated Basic Heart and Lung Ultrasound Examination for the Differentiation between Bacterial Pneumonia and Lung Neoplasm in Dogs—A New Diagnostic Algorithm

Simple Summary

Dyspnea is a highly alarming sign both for dog owners and veterinarians. Although its recognition is usually easy due to prominent suffering of an animal, finding its cause is challenging because many diseases of the heart, lungs, and airways may manifest themselves this way. Echocardiography and lung ultrasound allow for relatively quick and accurate identification of heart diseases. Dyspneic dogs without a heart and upper airway disease are usually suspected of either bacterial pneumonia or lung neoplasm. Although prognosis in these two conditions is diametrically different, differentiation between them is challenging. Chest radiography is performed in a lateral position, which is barely tolerated by a dyspneic dog, and intensive chest movements often make X-ray scans inconclusive. Computed tomography, although much more accurate, requires general anesthesia, which is difficult and potentially life-threating in a dyspneic dog. Therefore, lung ultrasound, which can be performed quickly in a conscious dog, standing or in sternal position, seems to be the method of choice. We develop and evaluate a diagnostic algorithm based on detection of three well-defined abnormalities in the lung ultrasound. The algorithm allows one to distinguish between bacterial pneumonia and lung neoplasm in a dyspneic dog with high probability of a conclusive result (91%) and high accuracy (>95%).

Abstract

The diagnostics of two of the most prevalent lung diseases in dogs, bacterial pneumonia (BP) and lung neoplasm (LN), are challenging as their clinical signs are identical and may also occur in extrapulmonary diseases. This study aims to identify ultrasonographic criteria and develop a lung ultrasound (LUS)-based diagnostic algorithm which could help distinguish between these two conditions. The study is carried out in 66 dyspneic dogs in which a heart disease was excluded using echocardiography. Based on imaging and laboratory diagnostic tests, as well as follow-up, the dogs are classified into LN (35 dogs) and BP (31 dogs) groups. LUS is performed at admission and the presence of seven lung abnormalities (pleural thickening, B-lines, subpleural consolidations, hepatization with or without aeration, nodule sign and mass classified together as a tumor, and free pleural fluid) and classification and regression trees are used to develop an LUS-based diagnostic algorithm. Distribution of all LUS abnormalities except for aerations differs significantly between groups; however, their individual differentiating potential is rather low. Therefore, we combine them in an algorithm which allows for definitive classification of 60 dogs (91%) (32 with LN and 28 with BP) with correct diagnosis of LN and BP in 31 dogs and 27 dogs, respectively.

Influence of concurrent lower respiratory tract disease on point-of-care lung ultrasound in small-breed dogs with myxomatous mitral valve disease

Background

Small‐breed dogs commonly have concurrent myxomatous mitral valve disease (MMVD) and lower respiratory tract disease (LRTD).

Hypothesis

Small‐breed dogs with preclinical MMVD and concurrent LRTD have more B‐lines on point‐of‐care lung ultrasound (POC‐LUS) compared to dogs without concurrent LRTD and are prone to misdiagnose as cardiogenic pulmonary edema (CPE).

Animals

A total of 114 small‐breed dogs with preclinical MMVD.

Methods

A prospective study was conducted, in which POC‐LUS was obtained and the number of B‐lines was calculated by a single clinician using the Veterinary Bedside Lung Ultrasound Examination protocol. The presence/absence of LRTD was assessed by clinicians blinded to the POC‐LUS results.

Results

Fifty and 64 dogs were in ACVIM stage B1 and B2, respectively. The presence of LRTD was prevalent in 74.6% (85/114) of small‐breed dogs with preclinical MMVD. When a previously reported criterion for CPE diagnosis (≥2 sites with >3 B‐lines/site) was applied, false‐positive results were observed in 15.8% (18/114) of dogs with preclinical MMVD. The summated number of B‐lines (3 vs. 1, P = .003), as well as the false‐positive rate (20% vs 3%, P = .04), were significantly higher in dogs with LRTD compared with dogs without LRTD. Multivariable logistic regression showed the presence of abnormalities other than B‐line on POC‐LUS (eg, thickened pleura or consolidation) could predict false‐positive results (odds ratio = 3.75, 95% confidence intervals 1.12‐12.54; P = .03) after adjustment for other clinical and echocardiographic factors.

Conclusions and Clinical Importance

Concurrent LRTD and abnormalities other than B‐lines should be considered in the interpretation of POC‐LUS in MMVD dogs.

Predictors of inflammatory lower airway disease in cats presented to the emergency room in respiratory distress: a case-control study

OBJECTIVES

The objective of the study was to identify whether venous blood gas (VBG) variables may serve as a predictor of inflammatory lower airway disease (ILAD) in cats presenting with respiratory distress. A secondary objective of this study was to compare the diagnostic utility of patient signalment, history and physical examination findings, as compared with VBG variables.

METHODS

The medical records of cats presenting with respiratory distress secondary to ILAD (54 cases) and non-ILAD (121 controls) were retrospectively reviewed.

RESULTS

No admission VBG variables were predictive of a final diagnosis of ILAD. Comparatively, multivariable analysis identified a history of a cough (P <0.001), increased respiratory rate (P = 0.001), the presence of an abdominal component to respiration (P = 0.007) and the absence of pleural effusion (P <0.01) to be independently associated with a final diagnosis of ILAD. Cats with a history of a cough and an abdominal component to respiration had 7.86 and 5.81 greater odds of being diagnosed with ILAD, respectively. Cats with pleural effusion had 7.43 lower odds of having this final diagnosis. For every 10 breaths/min increase in respiratory rate, cats had 1.48 greater odds of being diagnosed with ILAD. Cats diagnosed with ILAD had a survival rate of 94% (95% CI 84-99%) vs 61% (95% CI 51-70%) for non-ILAD controls (P <0.001).

CONCLUSIONS AND RELEVANCE

The results of this study found patient history and physical examination findings to be more useful predictors of a final diagnosis of ILAD in comparison with VBG variables at presentation. A history of a cough, an abdominal component to respiration and a lack of pleural effusion were found to be significant predictors of this diagnosis. Further investigation into the role of respiratory rate in ILAD is warranted.

Lung Ultrasound for Imaging of B-Lines in Dogs and Cats-A Prospective Study Investigating Agreement between Three Types of Transducers and the Accuracy in Diagnosing Cardiogenic Pulmonary Edema, Pneumonia and Lung Neoplasia

Transthoracic heart and lung ultrasound (LUS) was performed in 200 dogs and cats with dyspnea to evaluate the agreement between the results obtained using three types of transducers (microconvex, linear, and phased array) and to determine the accuracy of LUS in discriminating between three conditions commonly causing dyspnea in companion animals: cardiogenic pulmonary edema (CPE), pneumonia, and lung neoplasm. The agreement beyond chance was assessed using the weighted Cohen's kappa coefficient (κw). The highest values of κw (>0.9) were observed for the pair of microconvex and linear transducers. To quantify B-lines the lung ultrasound score (LUSscore) was developed as a sum of points describing the occurrence of B-lines for each of 8 standardized thoracic locations. The accuracy of LUSscore was determined using the area under ROC curve (AUROC). In dogs AUROC of LUSscore was 75.9% (CI 95%: 65.0% to 86.8%) for distinguishing between lung neoplasms and the two other causes of dyspnea. In cats AUROC of LUSscore was 83.6% (CI 95%: 75.2% to 92.0%) for distinguishing between CPE and the two other causes of dyspnea. The study shows that results obtained with microconvex and linear transducers are highly consistent and these two transducers can be used interchangeably. Moreover, the LUSscore may help identify dogs with lung neoplasms and cats with CPE, however its diagnostic accuracy is only fair to moderate.

Lung ultrasound nodule sign for detection of pulmonary nodule lesions in dogs: Comparison to thoracic radiography using computed tomography as the criterion standard

Thoracic radiography (TR), the most common screening test for pulmonary metastases in dogs, can fail to detect small lesions <3 mm. Lung ultrasonography (LUS) is a widely available imaging modality capable of detecting peripheral nodules but is underutilized for this purpose. Thoracic computed tomography (CT) is the criterion standard for diagnosis of lung metastases and nodular disease but is less practical for a variety of reasons. We hypothesized that LUS would be more sensitive but less specific at detecting nodules consistent with metastatic pulmonary disease in dogs compared to TR, using CT as the criterion standard. This was a masked, single-center prospective study of 62 client-owned dogs evaluated for respiratory signs or pulmonary metastatic neoplasia screening using TR, LUS and CT. Dogs were included if metastatic pulmonary disease was a differential. All imaging modalities were scored as having nodules (yes/no) and other types of pathologic lesions were recorded. Sensitivity (Se), specificity (Sp) and positive (LR+) and negative likelihood ratios (LR-) were determined for TR and LUS. For TR, Se and Sp were 64% and 73%, and LR+ and LR- were 2.37 and 0.49, respectively. For LUS, Se and Sp were 60% and 65% and LR+ and LR- were 1.71 and 0.62, respectively. The results of the study indicate that LUS had a similar Se to TR, with both modalities missing nodules when used for screening. The low Sp and LR- suggests caution should be used when assuming TR and LUS rule out the presence of nodules.

Comparison of curvilinear-array (microconvex) and phased-array transducers for ultrasonography of the lungs in dogs

OBJECTIVES

To compare the use of curvilinear-array (microconvex) and phased-array transducers for ultrasonographic examination of the lungs in dogs.

ANIMALS

13 client-owned dogs with left-sided congestive heart failure.

PROCEDURES

In a prospective methods comparison study, 24 ultrasonographic examinations of the lungs (4 sites/hemithorax) were performed with both curvilinear-array and phased-array transducers at 3 clinical time points. Two observers independently assessed the number of B lines (scored per site and in total), number of sites strongly positive for B lines (ie, those with > 3 B lines/site), and image quality (scored on a 5-point scale). Analyses included assessment of interobserver agreement with κ analysis, comparison of quality scores between transducers with mixed-effects modeling, and investigation of agreement and bias for B-line data and quality scores between transducers with Passing-Bablok regression.

RESULTS

Interobserver agreement for total B-line scores and number of strong-positive sites was excellent (κ > 0.80) for both transducers. There was no evidence of analytic bias for the number of B lines or strong-positive sites between transducers. Interobserver agreement for image quality scores was moderate (κ, 0.498 and 0.517 for the curvilinear-array and phased-array transducers, respectively). Both observers consistently assigned higher-quality scores to curvilinear-array images than to phased-array images.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated both curvilinear-array (microconvex) and phased-array transducers can be used by experienced sonographers to obtain diagnostic ultrasonographic images of the lungs in dogs with acute or resolving left-sided congestive heart failure and suggested the former transducer may be preferred, particularly to aid identification of anatomic landmarks for orientation.

Assessment of Volume Status and Fluid Responsiveness in Small Animals

Intravenous fluids are an essential component of shock management in human and veterinary emergency and critical care to increase cardiac output and improve tissue perfusion. Unfortunately, there are very few evidence-based guidelines to help direct fluid therapy in the clinical setting. Giving insufficient fluids and/or administering fluids too slowly to hypotensive patients with hypovolemia can contribute to continued hypoperfusion and increased morbidity and mortality. Similarly, giving excessive fluids to a volume unresponsive patient can contribute to volume overload and can equally increase morbidity and mortality. Therefore, assessing a patient's volume status and fluid responsiveness, and monitoring patient's response to fluid administration is critical in maintaining the balance between meeting a patient's fluid needs vs. contributing to complications of volume overload. This article will focus on the physiology behind fluid responsiveness and the methodologies used to estimate volume status and fluid responsiveness in the clinical setting.

Diagnostic accuracy of a lung ultrasound protocol (Vet BLUE) for detection of pleural fluid, pneumothorax and lung pathology in dogs and cats

OBJECTIVES

To assess the accuracy of the lung ultrasound protocol Vet BLUE, using thoracic CT as the reference standard, for the detection of thoracic pathology in dogs and cats.

MATERIALS AND METHODS

Animals that had thoracic ultrasound and thoracic CT were prospectively recruited between May 2017 and September 2018. The Vet BLUE protocol was performed on animals at the time of admission by veterinarians with basic training in emergency ultrasound. A board-certified radiologist, blinded to the Vet BLUE findings, reviewed the CT images.

RESULTS

CT was abnormal in 64.5% (20/31) animals. The number of CT sites positive for alveolar-interstitial syndrome was 24.2% (60/248). When using CT as the reference standard, detection of ≥3 B lines with thoracic ultrasound had a sensitivity of 18.33% and specificity of 98.4% for detection of site specific alveolar-interstitial syndrome. The sensitivity of Vet BLUE to detect alveolar-interstitial syndrome increased to 56.9% when including the presence of any B line as abnormal. Overall accuracy for detection of alveolar-interstitial syndrome based on these two criteria was 79% and 73%, respectively. Vet BLUE correctly identified consolidation in 58.3% (14/24) sites, pleural effusion in 66.6% (2/3) cases, pneumothorax in 33.3% (1/3) cases and intrathoracic mass in 25% (1/4) cases.

CLINICAL SIGNIFICANCE

The Vet BLUE protocol is a useful technique to detect alveolar-interstitial syndrome and other thoracic pathology but should not be used as a sole imaging method. Detection of ≥3 B lines is highly suggestive of alveolar-interstitial syndrome and warrants further diagnostics.

Diagnosis of pulmonary contusions with point-of-care lung ultrasonography and thoracic radiography compared to thoracic computed tomography in dogs with motor vehicle trauma: 29 cases (2017-2018)

OBJECTIVE

To determine the accuracy of lung ultrasound (LUS) using the Veterinary Bedside Lung Ultrasound Examination (VetBLUE) protocol and 3-view thoracic radiographs (TXR) compared to thoracic computed tomography (TCT) for diagnosing the presence and quantification of pulmonary contusions (PC).

DESIGN

Prospective cohort study conducted from February 2017 to June 2018.

SETTING

Private emergency and referral center.

ANIMALS

Thirty-two dogs having sustained motor vehicle trauma were consecutively enrolled. Three dogs were excluded from statistical analysis. All dogs survived to hospital discharge.

INTERVENTIONS

Within 24 hours of sustaining trauma, dogs had LUS, TXR, and TCT performed. Using the VetBLUE protocol, LUS PC were scored according to the presence and number of B-lines and C-lines, indicating extravascular lung water. Thoracic radiographs and TCT were scored for PC in a similar topographical pattern to the VetBLUE protocol. Lung ultrasound and TXR were compared to "gold standard" TCT for the presence and quantification of PC.

MEASUREMENTS AND MAIN RESULTS

On TCT, 21 of 29 (72.4%) dogs were positive and 8 of 29 (27.6%) dogs were negative for PC. When LUS was compared to TCT, 19 of 21 dogs were positive for PC (90.5% sensitivity) and 7 of 8 dogs were negative (87.5% specificity) for PC. LUS PC score correlated strongly with TCT PC score (R = 0.8, P < 0.001). When TXR was compared to TCT, 14 of 21 dogs were positive for PC (66.7% sensitivity) and 7 of 8 dogs were negative (87.5% specificity) for PC. TXR PC score correlated strongly with TCT PC score (R = 0.74, P < 0.001).

CONCLUSIONS

In this population of dogs with motor vehicle trauma, LUS had high sensitivity for diagnosis of PC when compared to "gold standard" TCT. LUS provides reliable diagnosis of PC after trauma. More patients with PC were identified with LUS than with TXR, and additional studies are warranted to determine whether this increased sensitivity is statistically significant.

Focused cardiac ultrasound and point-of-care NT-proBNP assay in the emergency room for differentiation of cardiac and noncardiac causes of respiratory distress in cats

OBJECTIVE

To assess the accuracy of focused cardiac ultrasound (FOCUS) and point-of-care N-terminal proBNP assay in the emergency setting for differentiation of cardiac from noncardiac causes of respiratory distress in cats.

DESIGN

Prospective diagnostic accuracy study between 2014 and 2016.

SETTING

Emergency room at an urban university teaching hospital.

ANIMALS

Forty-one client-owned cats presenting for evaluation of respiratory distress.

INTERVENTIONS

Emergency clinicians made an initial diagnosis of noncardiac or cardiac cause of respiratory distress based on physical examination (PE) findings and history. The diagnoses were updated after performing FOCUS and point-of-care N-terminal B-type natriuretic peptide (POC-BNP). Reference standard diagnosis was determined by agreement of a board-certified cardiologist and critical care specialist with access to subsequent radiographs and echocardiograms.

MEASUREMENTS AND MAIN RESULTS

Forty-one cats were enrolled. Three cats with incomplete data and 1 cat with an uncertain reference standard diagnosis were excluded. The remaining 37 cats were used for analysis: 21 cardiac and 16 noncardiac cases. The ratio of left atrial to aortic root diameter (LA:Ao) measured by FOCUS was significantly correlated with LA:Ao measured by echocardiography (R = 0.646, P < 0.0001). Emergency clinicians correctly diagnosed 27 of 37 (73.0%), yielding a PE positive percent agreement = 76.2% (95% CI, 52.8-91.8%) and negative percent agreement = 68.8% (95% CI, 41.3-89.0%). Five noncardiac and 5 cardiac cats were misdiagnosed. Post FOCUS, overall percent agreement improved to 34 of 37 (91.9%), with positive percent agreement = 95.2% (95% CI, 76.2-99.9%) and negative percent agreement = 87.5% (95% CI, 61.7-98.5%). The POC-BNP yielded an overall percent agreement = 32/34 (94.1%), positive percent agreement = 100% (95% CI, 82.4-100.0%), and negative percent agreement = 86.7% (95% CI, 59.5-98.3%) in differentiating cardiac versus noncardiac cases.

CONCLUSIONS

FOCUS evaluation of basic cardiac structure and LA:Ao by trained emergency clinicians improved accuracy of diagnosis compared to PE in cats with respiratory distress. FOCUS and POC-BNP are useful diagnostics in the emergent setting.

The use of focused cardiac ultrasound to screen for occult heart disease in asymptomatic cats

Background

Focused cardiac ultrasound (FCU) helps detect occult heart disease in human patients.

Hypothesis

Focused cardiac ultrasound by a nonspecialist practitioner (NSP) will increase the detection of occult heart disease in asymptomatic cats compared with physical examination and ECG.

Animals

Three hundred forty‐three client‐owned cats: 54 excluded and 289 analyzed.

Methods

Multicenter prospective cohort study. Twenty‐two NSPs were trained to perform FCU. Cats without clinical signs of heart disease were recruited, and NSPs performed the following in sequential order: physical examination, ECG, FCU, and point‐of‐care N‐terminal pro‐B‐type natriuretic peptide assay (POC‐BNP). After each step, NSPs indicated yes, no, or equivocal as to whether they believed heart disease was present. The level of agreement between the NSP diagnosis and a blinded cardiologist's diagnosis after echocardiogram was evaluated using Cohen's kappa test.

Results

Cardiologist diagnoses included 148 normal cats, 102 with heart disease, and 39 equivocal ones. Agreement between NSP and cardiologist was slight after physical examination (kappa 0.253 [95% CI, 0.172‐0.340]), did not increase after ECG (0.256 [0.161‐0.345]; P = .96), increased after FCU (0.468 [0.376‐0.558]; P = .002), and the level of agreement was similar after POC‐BNP (0.498 [0.419‐0.580]; P = .67). In cats with mild, moderate, and marked occult heart disease, the proportion of cats having a NSP diagnosis of heart disease after FCU was 45.6%, 93.1%, and 100%, respectively.

Conclusions and Clinical Importance

Focused cardiac ultrasound performed by NSPs increased the detection of occult heart disease, especially in cats with moderate to marked disease. Focused cardiac ultrasound appears to be a feasible and useful tool to assist NSPs in the detection of heart disease in cats.

Veterinary-focused assessment with sonography for trauma-airway, breathing, circulation, disability and exposure: a prospective observational study in 64 canine trauma patients

OBJECTIVE

To describe the technique and findings of the 'veterinary focused assessment with sonography for trauma-airway, breathing, circulation, disability and exposure' protocol in dogs suffering from trauma.

MATERIALS AND METHODS

Prospective observational study on a new point-of-care ultrasound protocol on 64 dogs suffering from trauma and comparison of findings with radiology.

RESULTS

Comparison of the results of this new ultrasound protocol for trauma patients with radiography findings for pneumothorax, pleural effusion, alveolar-interstitial syndrome and abdominal effusion revealed positive agreement of 89, 83, 100 and 87% and negative agreement of 76, 83, 76 and 92%, respectively. Novel findings of the 'veterinary focused assessment with sonography for trauma-airway, breathing, circulation, disability and exposure' exam, which were not previously reported for dogs undergoing focused assessment with sonography for trauma, included alveolar-interstitial syndrome (suggestive of pulmonary contusions), diaphragmatic hernia, retroperitoneal effusion and tracheal injury. Our new technique may also help identify increased intracranial pressure via changes in optic nerve sheath diameter and haemodynamic instability through the evaluation of the caudal vena cava and cardiac function.

CLINICAL SIGNIFICANCE

The described ultrasound examination protocol can be rapidly performed on dogs suffering from trauma during resuscitation and it may detect injuries previously undetectable using other veterinary point-of-care ultrasound protocols.

Evaluation of point-of-care thoracic ultrasound and NT-proBNP for the diagnosis of congestive heart failure in cats with respiratory distress

BACKGROUND

The diagnosis of congestive heart failure (CHF) in cats is challenging. Point-of-care (POC) thoracic ultrasound and NT-proBNP testing are emerging tools that may aid in diagnosis.

HYPOTHESIS/OBJECTIVES

To assess the diagnostic accuracy of POC lung ultrasound (LUS), focused cardiac ultrasound (FCU), and NT-proBNP in predicting a final diagnosis of CHF.

ANIMALS

Fifty-one cats in respiratory distress.

METHODS

Blood NT-proBNP, LUS, and FCU evaluating left atrial (LA) size and presence of pericardial effusion (PCEFF) were performed in all cats. Lung ultrasound findings including pleural effusion (PLEFF), number of B-lines, and sub-pleural abnormalities were noted. Medical records were evaluated for final diagnosis.

RESULTS

Thirty-three of 51 (65%) cats were diagnosed with CHF. Lung ultrasound and blood NT-proBNP were significant predictors of CHF in a multivariate model. The LUS criterion that maximized accuracy for CHF diagnosis was presence of >1 site strongly positive for B-lines (>3 B-lines per site), resulting in sensitivity of 78.8%, specificity of 83.3%, and area under the curve (AUC) of 0.833. Subjective LA enlargement was 97.0% sensitive and 100% specific for CHF (AUC 0.985). Presence of PCEFF also was 100% specific, but only 60.6% sensitive, for CHF (AUC 0.803). A positive blood NT-proBNP test was 93.9% sensitive and 72.2% specific for the diagnosis of CHF (AUC 0.831).

CONCLUSIONS AND CLINICAL IMPORTANCE

Point-of-care diagnostic techniques of LUS, FCU, and NT-proBNP are useful to diagnose CHF in cats with respiratory distress.

Distribution of alveolar-interstitial syndrome in dogs and cats with respiratory distress as assessed by lung ultrasound versus thoracic radiographs

OBJECTIVE

To assess distribution of alveolar-interstitial syndrome (AIS) detected by lung ultrasound (LUS) compared to thoracic radiographs (TXR).

DESIGN

Prospective study.

SETTING

University teaching hospital.

ANIMALS

Seventy-six dogs and 24 cats with acute respiratory distress or tachypnea.

INTERVENTIONS

Patients underwent LUS and TXR within 6 hours. Lung ultrasound images were scored for presence and quantity of B-lines in 4 lung quadrants (right cranial, right caudal, left cranial, left caudal). An individual LUS quadrant was scored positive if > 3 B-lines were observed within a single intercostal space. Dorsoventral TXR were scored for presence of AIS in the same 4 quadrants. An individual TXR quadrant was scored positive if infiltrate was present in ≥ 25% of the quadrant. Medical records were evaluated for final diagnosis.

MEASUREMENTS AND MAIN RESULTS

Quadrant-by-quadrant spatial agreement in assigning AIS using LUS versus TXR was fair (K = 0.24 - 0.56). Lung ultrasound scored a higher number of quadrants positive per patient (2.65 ± 1.59 vs. 2.13 ± 1.48; P = 0.012). Patterns of distribution of AIS differed significantly based on final diagnosis. Patients with left-sided congestive heart failure were more likely to have diffuse AIS on LUS (P < 0.001) or bilateral caudal AIS on TXR (P = 0.04) while patients with noncardiac disease were more likely to have absence of AIS in all quadrants using either modality (P < 0.001). Differences in spatial distribution of AIS were also noted among disease subcategories.

CONCLUSIONS

Lung ultrasound and TXR were both useful to detect and categorize distribution of alveolar or interstitial pulmonary pathology. Spatial agreement between modalities was only fair. Overall, LUS detected a higher incidence of AIS compared to TXR. Both modalities detected differences in distribution of AIS based on final diagnosis, suggesting that a regional pattern-based approach to thoracic imaging may prove diagnostically useful.