Aspiration Pneumonia in the Dog: A Review

Radiographic features of cardiogenic pulmonary oedema in dogs with dilated cardiomyopathy

OBJECTIVES

Dilated cardiomyopathy (DCM) is a common cause of acquired cardiac disorder in dogs, second only to myxomatous mitral valve disease (MMVD). This study aimed to describe the thoracic radiographic features of cardiogenic pulmonary oedema in dogs with DCM.

MATERIALS AND METHODS

Thoracic radiographs of dogs in left-sided congestive heart failure with an echocardiographically confirmed diagnosis of DCM were included in this retrospective study. Radiographs were retrospectively reviewed by two radiologists to assess the distribution, severity and characteristics of the pulmonary pattern, as well as to identify the presence of pleural effusion and degree of cardiomegaly.

RESULTS

A total of 97 dogs with L-CHF due to DCM met the inclusion criteria. Results of the study suggest that the predominant pulmonary pattern differs from myxomatous mitral valve disease and is characterised by a mild to moderate (62/97 or 63.9% and 30/97 or 30.9%, respectively), unstructured interstitial (72 or 74.2%), diffuse (90 or 92.8%) and predominantly ventrally distributed (52 or 53.6%) pulmonary pattern. A subset of dogs (49 or 50.5%) had diffusely distributed linear soft tissue opacities throughout all lung lobes considered to represent pulmonary vascular congestion, bronchial cuffing and/or thickening of the bronchi.

CLINICAL SIGNIFICANCE

The pulmonary pattern of L-CHF with DCM differs from what has been previously reported for dogs with MMVD. The predominant pulmonary pattern with L-CHF in dogs with DCM was a diffuse, marked, more severely ventrally distributed, mild to moderate, unstructured interstitial pulmonary pattern.

Point-of-Care Lung Ultrasound in Small Animal Emergency and Critical Care Medicine: A Clinical Review

Thoracic point-of-care ultrasound (T-POCUS) has grown in popularity and usage in small animal emergencies and critical care settings due to its non-invasive nature, mobility, and ability to acquire images in real time. This review summarizes current understanding about T-POCUS in dogs and cats with respiratory illnesses, including normal thoracic ultrasonography appearance and numerous pathological situations. The basics of T-POCUS are covered, including equipment, scanning procedures, and picture settings. Practical applications in patients with respiratory distress are discussed, with an emphasis on pleural space abnormalities and lung diseases. Ultrasound results define pulmonary disorders such as pneumonia, atelectasis, cardiogenic and non-cardiogenic pulmonary edema, lung lobe torsion, pulmonary fibrosis, pulmonary thromboembolism, pulmonary neoplasms, and pulmonary bleeding. The evaluation focuses on T-POCUS diagnostic skills in a variety of clinical settings. Limitations and the need for more study to standardize techniques, establish agreed terminology, and create specialized educational routes are highlighted.

Bioactive Adrenomedullin in Dogs with Sepsis and Septic Shock: A Prospective, Case-Control Study

Sepsis and septic shock are leading causes of morbidity and mortality in both humans and dogs, and early diagnosis is crucial for improving outcomes. This study aimed to evaluate bioactive adrenomedullin (bio-ADM) concentrations in dogs with septic shock (n = 25), dogs with sepsis without evidence of shock (n = 25), and healthy control dogs (n = 25). Plasma bio-ADM concentrations were measured using a human sandwich enzyme-linked immunosorbent assay and reported as median (interquartile range). Plasma bio-ADM concentrations were significantly higher in both septic groups compared to the healthy controls (all <22.4 pg/mL), but not significantly different between the septic shock (75.0 [28.7-115.0] pg/mL) and sepsis (30.7 [22.4-79.7] pg/mL) groups. Dogs with higher illness severity scores had significantly higher bio-ADM concentrations (93.1 [32.2-122.0] pg/mL) than those with lower scores (29.8 [22.4-71.2] pg/mL). However, bio-ADM concentrations did not differ between survivors (33.0 [22.7-76.7] pg/mL) and non-survivors (74.7 [26.1-123.2] pg/mL). Measurement of bio-ADM is a potential marker for canine sepsis, but not for the identification of septic shock, and may provide information on disease severity. Further studies, including those on non-infectious inflammatory conditions, are necessary to better understand the diagnostic utility of bio-ADM measurement and its potential role as a marker of treatment response in dogs with sepsis.

Relationship between Respiratory Rate, Oxygen Saturation, and Blood Test Results in Dogs with Chronic or Acute Respiratory Disease: A Retrospective Study

This study aimed to investigate the association of respiratory rate (RR), oxygen saturation (SpO2), and blood findings with respiratory disease in dogs and to compare the examination findings in the chronic and acute phases. Dogs that visited a veterinary referral hospital with respiratory symptoms were classified into the chronic disease group (GC), and those that visited the emergency veterinary hospital were classified into the acute disease group (GA). In total, 704 and 682 dogs were included in GC and GA, respectively. The RR and SpO2 were significantly higher and lower, respectively, in patients with lung disease compared to other disease sites in both groups. White blood cell counts were significantly increased in patients with lung and pleural diseases in both groups. Respiratory alkalosis and respiratory acidosis were most common in GC and GA, respectively. The C-reactive protein levels were elevated in both groups, primarily in patients with lung disease. Associations between the results of several tests for understanding and diagnosing respiratory conditions and diseases were recognized, and differences in the trends of the chronic and acute phases were clarified. These tools may be used as adjuncts to other tests for the diagnosis and monitoring of treatment responses.

Clinical Occurrences in the Neurorehabilitation of Dogs with Severe Spinal Cord Injury

This prospective observational clinical study in a population of tetraplegic and paraplegic dogs (n = 488) with or without deep pain sensation, similar to humans ASIA A and B, investigated the prevalence of clinical occurrences in a rehabilitation center with a hospitalization regime between 15 days and 9 months. A checklist of occurrences was used for easy identification and monitoring, resulting in a total of 79.5% occurrences. There were 58% of dogs with neurogenic bladder, 35.5% with diarrhea, 21.3% with urinary incontinence, and 20.5% with fecal incontinence. A low incidence of respiratory problems (e.g., pneumonia) and urinary tract infections may suggest the efficacy of some applied measures in this study, such as thoracic and abdominal POCUS evaluation, positioning strategies, physical exercises, respiratory kinesiotherapy, and early implementation of a functional neurorehabilitation protocol. These can be essential measures to prevent clinical occurrences, mainly in breeds such as the French Bulldog and the Dachshund.

Positive Airway Cultures in Dogs and Cats Receiving Mechanical Ventilation for Tick Paralysis

Animals with tick paralysis often require mechanical ventilation (MV) but previous publications have identified knowledge gaps regarding the development of bacterial pneumonia, and the specific pathogens involved. The objectives of this study were to describe the clinical course and culture and susceptibility profiles of bacteria isolated from airway samples of dogs and cats mechanically ventilated for tick paralysis that had positive airway cultures. Medical records were reviewed, and cases included if they had a positive airway sample culture during MV for tick paralysis. Twenty-four dogs and two cats were included. Most (85%) received empirical antimicrobials before airway sampling. The most common organisms isolated included Staphylococcus spp. (11), Klebsiella spp. (9), Enterococcus faecalis (8), Escherichia coli (6), Enterococcus faecium (3), Pseudomonas aeruginosa (4), and Mycoplasma spp. (3). Evidence of aspiration pneumonia was present in 22/25 (88%) cases that had thoracic radiographs performed. Seventy-seven percent of cases received antimicrobials to which the cultured bacteria were susceptible during hospitalisation. The median duration of MV was 4 days (range 1-10). Most (77%) survived to discharge, 19% were euthanised, and one died. In a multivariable logistic regression analysis it was identified that selection of antimicrobials to which the causative bacteria are susceptible was associated with survival to discharge (Odds ratio 45.8, p = 0.014; 95%CI 1.98-14,808), as was length of MV, with every day an animal is ventilated associated with a 4.7 times increased chance of survival (p = 0.015; 95% CI 1.21-78.4).

Antimicrobial discontinuation in dogs with acute aspiration pneumonia based on clinical improvement and normalization of C‐reactive protein concentration

Background

Evidence regarding optimal treatment duration in dogs with aspiration pneumonia (AP) and the role of thoracic radiographs (TXR) and lung ultrasonography (LUS) in the long‐term follow‐up of affected dogs is lacking. C‐reactive protein (CRP) is a reliable acute phase protein to monitor bacterial pneumonia in dogs.

Hypothesis

Investigate the safety of antimicrobial discontinuation based on clinical improvement and serum CRP normalization, as well as the usefulness of TXR and LUS for follow‐up.

Animals

Dogs diagnosed with AP and treated with antimicrobials.

Methods

Prospective observational study. Antimicrobials were discontinued based on clinical improvement and serum CRP normalization after 1, 3, or 5 weeks. At each consultation, a quality‐of‐life questionnaire, physical examination, serum CRP, TXR, and LUS were assessed. Short‐ (2 weeks) and long‐term (>1 month) follow‐ups after treatment discontinuation were performed to monitor for possible relapses.

Results

Seventeen dogs were included. Antimicrobials were discontinued after 1 week in 12 dogs (70.6%) and 3 weeks in the remaining 5 dogs (29.4%). Short‐term relapse was not observed in any dog and long‐term relapse was diagnosed in 3 dogs. Thoracic radiographs and LUS were useful for diagnosis, but did not add additional information during follow‐up, because image normalization lagged behind clinical improvement and serum CRP normalization.

Conclusion and Clinical Importance

Dogs with AP can be safely and effectively treated using a short‐term antimicrobial regimen discontinued after clinical improvement and serum CRP normalization. Imaging might still be useful for complicated cases with a less favorable response to treatment.

Comparison of lung ultrasound, chest radiographs, C-reactive protein, and clinical findings in dogs treated for aspiration pneumonia

Background

Comparison of clinical findings, chest radiographs (CXR), lung ultrasound (LUS) findings, and C‐reactive protein (CRP) concentrations at admission and serial follow‐up in dogs with aspiration pneumonia (AP) is lacking.

Hypothesis

Lung ultrasound lesions in dogs with AP are similar to those described in humans with community‐acquired pneumonia (comAP); the severity of CXR and LUS lesions are similar; normalization of CRP concentration precedes resolution of imaging abnormalities and more closely reflects the clinical improvement of dogs.

Animals

Seventeen dogs with AP.

Methods

Prospective observational study. Clinical examination, CXR, LUS, and CRP measurements performed at admission (n = 17), 2 weeks (n = 13), and 1 month after diagnosis (n = 6). All dogs received antimicrobial therapy. Lung ultrasound and CXR canine aspiration scoring systems used to compare abnormalities.

Results

B‐lines and shred signs with or without bronchograms were identified on LUS in 14 of 17 and 16 of 17, at admission. Chest radiographs and LUS scores differed significantly using both canine AP scoring systems at each time point (18 regions per dog, P < .001). Clinical and CRP normalization occurred in all dogs during follow up. Shred signs disappeared on LUS in all but 1 of 6 dogs at 1 month follow‐up, while B‐lines and CXR abnormalities persisted in 4 of 6 and all dogs, respectively.

Conclusion and Clinical Importance

Lung ultrasound findings resemble those of humans with comAP and differ from CXR findings. Shred signs and high CRP concentrations better reflect clinical findings during serial evaluation of dogs.

Anatomic characterization of the location of the esophageal ostium relative to the rima glottidis on CT in adult Labrador Retrievers

OBJECTIVE

To characterize the anatomic location of the esophageal ostium relative to the rima glottidis in adult Labrador Retrievers with the use of CT.

ANIMALS

98 CT scans of 75 adult Labrador Retrievers.

PROCEDURES

A search of the medical records database identified records of Labrador Retrievers that underwent CT of the head and neck between January 1, 2015, and December 31, 2018. Evaluators, blinded to each other's results, reviewed CT images and measured esophageal area at the level of the rima glottidis. For each dog, the left esophageal percentage (LEP) was calculated as the esophageal area left of the rima glottidis midline divided by the overall esophageal area at that level. Variables (age, sex, patient position, intubation status, and maxillary support during CT) were evaluated for association with LEP. The CT images of dogs that had multiple scans were assessed for within-patient variance.

RESULTS

Mean LEP was 56.2 ± 18.1% for all dogs. Only right lateral recumbency was significantly associated with LEP, with a lower LEP for dogs positioned in right lateral recumbency (42.4 ± 12.7%), compared with left lateral (63.0 ± 7.4%) or sternal (57.3 ± 18.8%) recumbency. No association was detected between LEP and other variables assessed. Eleven dogs had multiple CT scans; within-patient variance for LEP was ± 26.6%.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that, although most dogs had an LEP > 50%, the esophageal ostium was fairly centrally located in most dogs and may be more mobile than previously thought. Additional research is warranted to assess this mobility and whether the esophageal ostium location, relative to the larynx, affects the incidence of aspiration pneumonia in dogs undergoing surgical treatment for geriatric-onset laryngeal paralysis and polyneuropathy.

Bacterial infection in dogs with aspiration pneumonia at 2 tertiary referral practices

Background

In dogs, antimicrobial drugs are widely prescribed for aspiration pneumonia (AP) despite poor documentation of bacterial infection in AP (b‐AP) using bronchoalveolar lavage fluid (BALF) analysis. Interpretating discordant cytology and culture results is challenging, contributing to lack of a criterion standard, and highlighting differences between veterinary and human medical criteria for b‐AP.

Objectives

Determine how many dogs with AP had BALF collection and differences in diagnosis of b‐AP using veterinary vs human medical criteria. Report findings of noninvasive markers (e.g. fever, band neutrophilia, radiographic severity score) in dogs with and without b‐AP.

Animals

Retrospective cohort study of client‐owned dogs (n = 429) with AP at 2 university veterinary hospitals. Twenty‐four dogs met enrollment criteria.

Methods

Inclusion criteria were radiographic diagnosis of AP, ≥1 risk factor, CBC findings, and BALF cytology and culture results. Veterinary medical b‐AP criteria were cytology findings compatible with sepsis with or without positive culture, or cytology findings not consistent with sepsis and positive culture (≥1.7 × 10³ cfu/mL). Human medical b‐AP criteria required culture with ≥10⁴ cfu/mL or > 7% cells with intracellular bacteria on cytology.

Results

Only 24/429 dogs met all enrollment criteria; 379/429 dogs lacked BALF collection. Diagnosis of b‐AP differed using veterinary (79%) vs human (29%) medical criteria. Fever, band neutrophils and high radiographic scores were noted in dogs with and without b‐AP.

Conclusions and Clinical Importance

Lack of routine BALF collection hampers definitive recognition of bacterial infection in AP. Differences in dogs meeting veterinary vs human medical definitions for b‐AP and usefulness of noninvasive markers warrant further study to improve understanding of the role of bacteria in AP.

Retrospective investigation of the neutrophil-to-lymphocyte ratio in dogs with pneumonia: 49 cases (2011-2016)

OBJECTIVE

To assess the utility of the neutrophil-to-lymphocyte ratio (NLR) in predicting outcome in canine pneumonia compared with routine hematological parameters and systemic inflammatory response syndrome (SIRS) scores.

DESIGN

Retrospective study.

SETTING

University teaching hospital.

ANIMALS

Forty-nine client-owned dogs.

INTERVENTIONS

None MEASUREMENTS AND MAIN RESULTS: Medical records were reviewed to identify dogs with a diagnosis of pneumonia from July 2011 to December 2016. Signalment, clinical findings, laboratory characteristics, and outcome were recorded. Inclusion criteria were a clinical and radiographic diagnosis of pneumonia, plus reference laboratory hematology at diagnosis. Cases that received steroids were excluded. Euthanized dogs were only included in statistical analysis if euthanized solely due to pneumonia severity. The NLR, total WBC count, neutrophil count, lymphocyte count, band neutrophil percent of total WBC count (%-bands), and percentage of cases diagnosed with SIRS were compared between survivors and nonsurvivors. Receiver operating characteristic curves were generated to identify optimal sensitivity and specificity cutoffs for nonsurvival to discharge. Two hundred records were retrieved; 49 cases fulfilled the inclusion criteria. Of these, 33 (67%) survived to discharge. The NLR did not differ significantly between the survivors and nonsurvivors, nor did total WBC count or neutrophil count. Survivors had a significantly lower %-bands than nonsurvivors (P < 0.001) and higher lymphocyte count (P = 0.004). The mortality rate did not differ significantly between dogs with and without SIRS. Receiver operating characteristic analysis identified a %-bands cutoff of 2.5% or higher had an 83% sensitivity and 79% specificity for nonsurvival.

CONCLUSIONS

Unlike in human medicine, neither NLR nor SIRS scores predicted outcome in this cohort of dogs with pneumonia. However, survivors had a lower %-bands and higher lymphocyte count than nonsurvivors, which may be helpful prognostically in clinical cases.

Effectiveness of chest physiotherapy using passive slow expiratory techniques in dogs with airway fluid accumulation: A randomized controlled trial

BACKGROUND

Prolonged slow expiration (PSE) and assisted cough (AC) are airway clearance techniques feasible and well tolerated in dogs.

OBJECTIVES

To evaluate the effectiveness of PSE and AC as chest physiotherapy (CP) techniques in dogs with airway fluid accumulation.

ANIMALS

Thirty-one client-owned dogs hospitalized in an intensive care unit from October 2014 to May 2018.

METHODS

Prospective randomized controlled trial. Dogs presented with or developing acute dyspnea during hospitalization associated with airway fluid accumulation were assigned to CP group (medical treatment and CP, 15 dogs) or control group (medical treatment alone, 16 dogs). The arterial partial pressure of oxygen (PaO2 ) to fraction of inspired oxygen (FiO2 ) ratio (P/F ratio; PaO2 /FiO2 × 100) was calculated daily for the 1st 48 hours of hospitalization and using the last arterial blood gas performed before discharge or death. The ratio of days of hospitalization with oxygen/total number of hospitalization days (ratio of oxygen-free-days [O2 Free]) was calculated.

RESULTS

During the 1st 48 hours, the P/F ratio increased significantly in the CP group compared to the control group (+ 35.1 mm Hg/day; 95% confidence interval [CI] = 0.4-57.5; P = .03). The (median; 1st quartile to 3rd quartile) difference between the P/F ratio at discharge and inclusion was significantly higher in the CP group (178 mm Hg; 123-241) than in the control group (54 mm Hg; -19 - 109; P = .001). Mean O2 Free increased by 46.4% in the CP group compared with control group (95% CI = 16-59; P = .001). Mortality was 13% (2/15) in the CP group and 44% (7/16) in the control group (P = .07).

CONCLUSIONS AND CLINICAL IMPORTANCE

Prolonged slow expiration and AC improved P/F ratio within 48 hours and decreased need for oxygenation in dyspneic dogs with acute airway fluid accumulation.

Professional dental cleaning in dogs: clinical routines among Swedish veterinarians and veterinary nurses

BACKGROUND

Dental disease is very common in dogs and veterinary professional dental cleaning and examination, together with daily dental home care, is the foundation for good dental health. To our knowledge, no previous study has investigated professional dental cleaning routines in small animal veterinary practice. A validated questionnaire survey was distributed to all veterinarians and veterinary nurses with registered e-mail addresses in the Swedish national registry (veterinarians; n = 3657, veterinary nurses; n = 1650). Response rates were 32% for veterinarians (V) and 38% for veterinary nurses (VN).

RESULTS

In total, 73% (V)/96% (VN) of respondents reported that professional dental cleaning was performed at their work place under general anesthesia, and 27% (V)/18% (VN) that dental cleaning was performed under sedation. Of the respondents, 43% (V)/96% (VN) considered regular dental cleaning under general anesthesia fairly or very important, and 49% (V)/47% (VN) stated that it was sometimes important for good dental health in dogs. A majority of respondents, 84% (V)/97% (VN), reported that dental extractions were performed at their clinic, and 72% (V)/90% (VN) had access to dental radiography equipment.

CONCLUSION

A majority of Swedish veterinarians and veterinary nurses perform professional dental cleaning under general anesthesia with access to dental radiography equipment, in accordance with national and international recommendations. However, a considerable proportion of professional dental cleanings were performed under sedation only, and extractions performed without access to dental radiography equipment were common, suggesting several areas of improvement in the routines in Swedish veterinary clinics and hospitals. Our results clearly indicate the need for improved educational efforts to increase the awareness among veterinary health professionals regarding guidelines and official recommendations in canine dental care.

Retrospective evaluation of the use of hemodialysis in dogs with suspected metaldehyde poisoning (2012-2017): 11 cases

OBJECTIVE

To evaluate dogs treated with hemodialysis for severe metaldehyde intoxication and to compare them with conventionally-managed patients.

DESIGN

Retrospective study (2012-2017).

SETTING

University teaching hospital.

ANIMALS

Data from 18 dogs with severe metaldehyde intoxication were analyzed. Eleven dogs were treated with intermittent hemodialysis and 7 managed conventionally.

INTERVENTIONS

None.

MEASUREMENT AND MAIN RESULTS

Metaldehyde poisoning was diagnosed based on clinical signs and toxicological analysis or presence of turquoise material in the gastrointestinal content. Clinical signs, additional treatments, dialysis prescription, duration of anesthesia and hospitalization, complications, and outcome were documented. Results were analyzed by t-test, Mann-Whitney U-test, and Chi-square test. P < 0.05 was considered significant. Dialysis was performed for median (range) 180 min (150-420 min) with median of 2.28 L/kg (1.66-4.48 L/kg) blood volume processed. In the hemodialysis group, anesthesia was discontinued at a median of 3.0 hours (1.5-6.7 h) after starting dialysis. The conventional-group received general anesthesia for a median of 17.5 hours (7.0-30.5 h). No further anticonvulsive treatment was necessary for the hemodialysis group. Time to hospital discharge was shorter in dialyzed dogs (median 18 h; 15-41 h) compared to conventionally treated dogs (median 89 h; 61-168 h; P = 0.0014). Aspiration pneumonia was reported in 5 conventionally treated dogs and none of the dialyzed dogs (P = 0.001). Five dialyzed dogs developed hematoma at the dialysis catheter site. One dog in each group was euthanized.

CONCLUSION

Hemodialysis significantly decreases the requirement for anesthesia and length of hospitalization in dogs with metaldehyde intoxication. Aspiration pneumonia occurred less often in dialyzed patients. Prospective studies are warranted to confirm the clinical utility of hemodialysis in dogs with metaldehyde poisoning.