The ultimate guide to navigating CHF emergency cases, part 1

 

The sedation effects of butorphanol can last 2-4 hours (or less). Thus, in some of the respiratory patients, frequent dosing may be warranted.² Generally, I will dose q 6 hours unless respiratory fatigue is severe or they are struggling, and or if adjunct drugs are contraindicated. I have used it hourly for some patients when needed.

Providing this in triage helps patients calm down, reduces the work of breathing in some cases, and often facilitates IV catheter placement and diagnostic testing once the patient stabilizes sufficiently.¹

Respiratory distress: Is it primary cardiac or not?

When a patient presents with trouble breathing, we need to be able to discern whether the primary condition is of pulmonary, cardiac, or upper airway origin. That will help guide treatment, diagnostics, and even prognosis.

Localizing respiratory distress

When a patient arrives struggling to breathe, the first step is to determine whether the patient has upper airway or lower airway disease.

Upper airway disease is usually audible without a stethoscope and may include stertor +/- stridor. Think about dogs with laryngeal paralysis; they sound hoarse, and they are loud. For lower airway disease, are the lung sounds loud or quiet? For quiet lung sounds, we often need to consider primary pulmonary disease or a pleural space process. This may be a pneumothorax or pleural effusion. This patient may need a chest tap.^1,3,4

For loud lung sounds, we need to distinguish between:^1,3

1. Primary cardiac, namely CHF
2. Pulmonary disease, generally either feline asthma or bronchitis in the dog

The presence or absence of muffled heart sounds, loud lung sounds, crackles, wheezes, and cough may help further localize the disease, but recognizing where the problem lies is half the battle!

Generally, patients with disease outside the chest will have increased inspiratory effort, whereas those with expiratory effort have intrathoracic disease. When we hear crackles or have tracheal sensitivity, we initially suspect bronchial disease; however, in the presence of sound attenuation or paradoxical breathing, we must consider the diaphragm or pleura as the primary problem.⁵

Clinical signs of CHF

The key hallmark signs suggestive of heart failure in the dog/cat, most commonly seen with left-sided or global CHF, are:^6–8

1. Tachypnea
2. Dyspnea

A cough doesn't have to be present to indicate CHF in dogs, and remember, coughing is not generally a characteristic of CHF in cats (think asthma). While coughing is common in dogs with CHF, it is more commonly associated with myxomatous valvular disease (MMVD) than with dilated cardiomyopathy (DCM). It can also indicate other conditions, such as allergic bronchitis, bronchomalacia, bronchiectasis, pulmonary fibrosis, neoplasia, or eosinophilic bronchopneumopathy.^3,8 Thus, localization of respiratory signs is key.

Remember with coughing in dogs with CHF, the cough is not directly related to the underlying heart disease. "Cardiac cough" still originates from the airways, albeit secondary to enlarged heart and compression of the primary airways +/- concurrent airway disease (e.g., tracheal collapse, GERD,  bronchomalacia, or chronic bronchitis patients).⁸

Additional clinical signs may be non-specific and vague, and not always recognized as related to an underlying condition, simply attributed to a pet's aging. These may include^7,8

• Hyporexa to anorexia
• Exercise intolerance (stopping more frequently on walks, not wanting to walk as far, getting tired faster)
• Anxiety +/- cognitive changes
• Lethargy
• Low body temperature (carries a worse prognosis)

Clinical exam findings supporting a diagnosis of CHF will vary with species, breed, left vs. right vs. global CHF, and underlying disease (HCM, valvular vs. DCM), but often include:^6–8

• Weak femoral pulses
• Elevated heart rates
• Abnormal cardiac rhythms
• Cyanosis
• Rapid breathing, which, with CHF, we often see being very short and shallow
• Increased bronchovesicular sounds +/- crackles (Remember, though, we can also auscult this with pneumonia or fibrosis of the lungs, so it isn't pathpneumoic)
• Palor
• Dogs with valvular illness usually have a heart murmur, which is louder in small breed dogs but milder in large breed dogs, though the reasons are not fully elucidated.
• Cats may or may not present in CHF with a heart murmur.⁹
• Auscultation of lung sounds is widely variable and may be dull or harsh, with or without crackles. Not hearing or recognizing an abnormality doesn't rule it out.
• Heart sounds are usually well ausculted unless there is the presence of air or fluid in the pleural space. In dogs, pleural effusion is not usually a hallmark finding; however, in cats, all bets are often off, and many cats with CHF present with pleural effusion. They may have muffled heart sounds and dull lung sounds.¹⁰

Interestingly, if you can appreciate sinus respiratory arrhythmia, your patient is unlikely to have heart failure. According to Luca Ferasin, DVM, PhD, CertVC, PGCert(HE), Dipl. ECVIM-CA (Cardiology), GPCert (B&PS), FRCVS, a veterinary cardiologist, the increase in heart rate seen with inspiration and the lower rates during expiration do not occur in patients with CHF because of changes in sympathetic and parasympathetic tone. If a patient presents in distress with sinus respiratory arrhythmia, consider primary pulmonary disease as a differential diagnosis; CHF would be much lower on the list.⁸

Diagnostics

Once we have the pet stable enough, while we can glean a lot from our history and physical exam findings, we still want some diagnostics to help hone in on the diagnosis, provide means for comparison moving forward, and assist with prognosis and medication selection.

Some beneficial, minimally invasive diagnostics we can start with include:^1,7

1. Thoracic POCUS (tFAST^®)
2. SpO₂ (Pulse oximetry)
3. Renal values (If we place an IVC without too much stress and can draw a small sample of blood from the catheter, we may be able to get a mini panel, venous blood gas, or related information that can often give pH, electrolytes, and baseline kidney values (maybe even before that first dose of a diuretic). However, not all practices have this capability, but for those that do, it can be beneficial.

A quick mention of SpO₂. What is normal? We consider 95-100 percent normal in dogs and cats, unless other parameters indicate otherwise. Anything less than 93 percent requires oxygen therapy, and per the criticalists, anything less than 90 percent is severely adverse. However, we need to ask ourselves a few things when attempting to interpret readings:⁴

1. Is it accurate?
2. What are its limitations? Is the heart rate matching the patient's? Are you getting consistent readings, or is it jumping all over the place? Does your patient have pigmented gums or dark skin that may negatively impact the probe's ability to read correctly?

When functioning properly, however, the SpO₂ can provide valuable information when coupled with an EPOC, NOVA, I-Stat, or similar blood gas analyzer. Consider venous blood gas and an accurate SpO₂are approximately equivalent to an arterial blood gas.¹

When stable, obtaining baseline bloodwork (if not feasible upon catheter placement) would include, at a minimum:^1,7

• Baseline renal values (Bun, crea, electrolytes, +/- P).
• Electrolytes
• PCV/TP

Baseline values will guide diuretic therapy, dosing, and frequency; determine whether ACE inhibitors can be added safely or with caution; and inform the owner of the pros/cons and the possible underlying renal disease.⁷

POCUS: Depending on your comfort and skill levels, this tool can be useful. If you have a high-quality machine that enables you to identify cardiac structures in all patients readily, this is beneficial. If not, being able to rule in or out pericardial and pleural effusion and to identify B-lines can at least give you an idea of whether there is effusion and wet lungs.^6,8,11 (See Veterinary Practice News "Using ultrasound in the ER setting, Part 2", for more information on using POCUS to improve diagnostic acuity.) [Will do hyperlink in WP; https://www.veterinarypracticenews.com/using-ultrasound-emergency-setting-part-2/]

Once your patient is stable, it is always ideal to obtain thoracic radiographs, ideally three views (both laterals and DV). This permits accurate evaluation of cardiac size and chamber enlargement, as well as assessment of the presence of pulmonary edema versus non-cardiogenic-induced changes. Having baseline radiographs also permits comparison later if the patient declines or improves, then declines again, and for serial monitoring over time.

Additional options, depending on availability and on the test available, include measuring pro-BNP levels. If a qualitative test reports only abnormal or normal, normal indicates respiratory distress is unlikely to be of cardiac origin; abnormal may indicate multiple causes. A qualitative test may be more consistent with CHF, with higher values supportive of true failure. The utility and evidence are still being gathered, and we have several tools at our fingertips to support a diagnosis of CHF. Still, this test isn't the end-all and be-all and likely won't change outcomes/therapy when combined with the aforementioned diagnostics.¹²

Finally, if feasible and the patient is stable, an echocardiogram is always beneficial for assessing cardiac function, evaluating for pulmonary hypertension, and more. Still, it is not readily accessible in many cases and is not necessary for the successful management of a patient with acute heart failure. Once a patient stabilizes, though, we should offer referral or suggest consultation with a cardiologist for all patients. Whether the owners' decision to pursue this is theirs is immaterial; it should remain on the table for owners seeking more information and for additional supportive management as they transition from acute to chronic CHF management.

(Part two continues with a comprehensive look at ER management of CHF, when to intubate, and client education.)

Erica Tramuta-Drobnis, VMD, CPH, is the CEO and founder of ELTD One Health Consulting, LLC. Dr. Tramuta-Drobnis works as a public health professional, emergency veterinarian, freelance writer, consultant, and researcher. She is passionate about One Health issues and believes that addressing pet health, food safety, agricultural health, and other related concerns can help highlight the interconnection of human, animal, and environmental health. Veterinarians are primed to be at the forefront of One Health initiatives, and she is passionate about issues from antimicrobial resistance to infectious disease control, vaccination health, and wildlife conservation. She is a strong advocate of evidence-based veterinary medicine and the president-elect of the Evidence Based Veterinary Medical Association (EBVMA). She hopes to promote the use of evidence-based practices through her writing and clinical work, preserving the human-animal bond and improving health outcomes within a One Health context.

References

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2. Plumb's Veterinary Drugs. Butorphanol. Plumb's. Accessed January 10, 2026. https://app.plumbs.com/drug/qZ8Rb9KuWcPROD?source=search&searchQuery=butorphanol
3. Johnson LR. Localization of Disease. In: Canine and Feline Respiratory Medicine. John Wiley & Sons, Ltd; 2025:1-14. doi:10.1002/9781394233397.ch1
4. Reinero C. World Small Animal Veterinary Association Congress Proceedings, 2019. In: World Small Animal Veterinary Association Congress Proceedings, 2019. World Small Animal Veterinary Association Congress; 2019. Accessed January 15, 2026. https://www.vin.com/doc/?id=9382661
5. Domínguez-Ruiz M, Reinero CR, Vientos-Plotts A, et al. Association between respiratory clinical signs and respiratory localization in dogs and cats with abnormal breathing patterns. Vet J. 2021;277:105761. doi:10.1016/j.tvjl.2021.105761
6. Ferasin L, DeFrancesco T. Management of acute heart failure in cats. J Vet Cardiol. 2015;17:S173-S189. doi:10.1016/j.jvc.2015.09.007
7. Keene BW, Atkins CE, Bonagura JD, et al. ACVIM consensus guidelines for the diagnosis and treatment of myxomatous mitral valve disease in dogs. J Vet Intern Med. 2019;33(3):1127-1140. doi:10.1111/jvim.15488
8. Ferasin L. Acute heart failure in dogs. Royal Canin Academy. March 29, 2023. Accessed January 12, 2026. https://academy.royalcanin.com/en/veterinary/acute-heart-failure-in-dogs
9. Luis Fuentes V, Abbott J, Chetboul V, et al. ACVIM consensus statement guidelines for the classification, diagnosis, and management of cardiomyopathies in cats. J Vet Intern Med. 2020;34(3):1062-1077. doi:10.1111/jvim.15745
10. Pachtinger G, Brashear ML. Common Respiratory Diseases. Accessed January 12, 2026. https://www.aaha.org/wp-content/uploads/globalassets/03-education/connexity/er-bootcamp_segment-6---common-respiratory-diseases---pachtinger-and-brashear.pdf#:~:text=*%20Upper%20airway%20disease%20(stertor%2C%20stridor%2C%20inspiratory,disease:%20(increased%20bronchovesicular%20sounds%2C%20crackles%2C%20rapid%20shallow.
11. Tramuta-Drobnis EL. Essential point-of-care tests for veterinarians, part 2: The tFAST3 scan. IndeVets. September 13, 2022. Accessed December 11, 2022. https://indevets.com/blog/essential-point-of-care-tests-for-veterinarians-part-2-the-tfast3-scan/
12. Tramuta-Drobnis EL. Veterinary point-of-care tests: Evidence-based insights. Vet Pract News. 2024;36(12):18-20.