Clinical ultrasound recognized in emergency medicine

Paris, France – How to ensure a good diagnosis during emergency treatment of dyspnea in the elderly? During the congress Emergencies 2022 , one session took stock of the means to be used in this common situation, with a prominent place being given to clinical ultrasound, which could replace the chest scanner in the diagnostic process. With or without the support of natriuretic peptides.

“It has been clearly demonstrated that clinical ultrasound, in addition to improving diagnosis, also allows for a reduction in the time in the emergency department of dyspneic patients,” commented the dr Tomislav Petrovic (Hôpital Avicenne, AP-HP, Bobigny), moderator of this session. In about ten minutes, a lung ultrasound supplemented by a Doppler examination can help to diagnose heart failure.

The treatment of acute shortness of breath is always a challenge for the emergency physician, especially in older people, since age-related physiological changes, a decrease in respiratory capacity or comorbidities make the search for the causes of shortness of breath more complex.

A third of misdiagnosed elderly patients

The standard diagnostics with questioning, clinical examination, electrocardiogram (ECG) and chest x-ray seem to be ineffective. “It is estimated that the diagnosis made and the treatment initiated are inadequate in one third of dyspnea patients aged 65 years and over”, which has a direct impact on the prognosis, the underlined Dr Patrick Ray (CHU Dijon Bourgogne), during his intervention [1].

It is estimated that one third of dyspnea patients aged 65 years and older have inadequate diagnosis and treatment.
Dr Patrick Ray

In an observational study conducted by the emergency physician and his colleagues at Dijon University Hospital, this treatment of acute dyspnea, resulting in inappropriate treatment, was associated with in-hospital mortality that was twice as high in elderly patients with dyspnea. Mortality is also increased when the diagnosis is considered uncertain [2].

Acute pulmonary edema associated with heart failure is the most common cause of dyspnea in this population (40% of cases). The causes of pulmonary origin are mainly the exacerbation of chronic obstructive pulmonary disease (COPD), pneumopathy and pulmonary embolism. In the elderly, the causes of dyspnea are diverse in almost half the cases.

First, the diagnosis of COPD should no longer be systematically made if the elderly patient presents with wheezing dyspnea, since this symptom can also be associated with acute edema in this population, the reminded dr Thibaut Markarian (Hospital Timone, Marseille) during his presentation [3]. “A third of patients over 65 with heart failure have shortness of breath.”

If the elderly patient presents with wheezing dyspnea, the diagnosis of COPD should no longer be made systematically.
dr Thibaut Markarian

Comet Tail Artifact Search

Pleuropulmonary ultrasound is now a diagnostic tool of choice for a rapid examination of the lungs to identify a cardiac cause by looking for a “line B” type comet-tail artifact, a sign of the presence of edema, the emergency physician pointed out .

Regarding the use of the natriuretic peptides BNP and NT-proBNP, powerful biomarkers of heart failure, their interest in the elderly population is questioned, recalls the dr Philippe Le Conte (CHU de Nantes), who spoke during this session to discuss the cardiac causes of dyspnoea [4].

One of the disadvantages: the threshold values ​​​​of BNP and NT-proBNP, which make it possible to confirm or rule out heart failure, differ according to age, which widens the window of uncertainty in older people, the emergency doctor reminded. In NT-proBNP, patients aged 75 years and older have heart failure in NT-proBNP < 300 pg/ml unwahrscheinlich und bei NT-proBNP > 1,800 pg/mL very likely.

In addition, a high BNP can also indicate chronic heart failure or sepsis caused by pneumonitis. “The highest BNP levels I have seen were associated with pneumonia, with levels reaching 5,000 to 10,000 pg/mL. And studies have shown that sepsis with a high BNP does not necessarily correlate with heart failure. »

Doppler to confirm heart failure

An approach that favors lung and cardiac ultrasound seems most appropriate in this situation, believes Dr. Le Conte. The presence of bilateral and diffuse B-lines (comet tail) on ultrasound is associated with greater than 90% specificity and sensitivity in the diagnosis of acute pulmonary edema.

Since the observation of a changed left ventricular ejection fraction (LVEF) in cardiac ultrasound is not sufficient to diagnose heart failure, additional examinations using Doppler ultrasound with special algorithms should be considered. According to more recent studies, a Doppler parameter E/E’>15 confirms the diagnosis.

“Ultrasound has a clear performance advantage in diagnosing cardiac causes of respiratory distress. The examination can be performed in about ten minutes and is relatively easy for trained emergency physicians,” says Dr. Le Conte concludes.

Ultrasound has a clear performance advantage in diagnosing cardiac causes of dyspnea.
dr Philippe Le Conte

A well-performed ultrasound can diagnose heart failure without the dose of natriuretic peptides present, he believes.

X-ray images “difficult to interpret”

In the case of the search for pneumopathy, Dr. Markarian notes that “the usual clinical signs are much less common in older patients,” making diagnosis more difficult. Fever, for example, occurs in only one in two patients.

Here, too, pleuropulmonary ultrasound improves the diagnostic performance compared to chest x-rays, which are often “difficult to interpret”. Supplemented by a cardiac ultrasound, it increases the sensitivity of standard diagnostics in the search for infectious pneumopathy from 25 to 83% in elderly patients with respiratory distress. [5].

If pulmonary embolism is suspected, the guidelines distinguish between patients in shock and stable patients. In the state of shock, priority should be given to echocardiography in order to look for signs of “acute cor pulmonale” (acute dilatation of the right ventricle, dyskinesia of the paradoxical septum, etc.) and, if necessary, to treat thrombolysis.

In patients with stable dyspnea, “the diagnosis of a pulmonary embolism is much more complicated” because the clinical symptoms are “very variable and not very specific,” emphasizes Dr. Markarian. Chest x-ray is of little use except for differential diagnosis, and blood gas analysis indicates normal pulse oxygen saturation (SP02) in 40% of cases.

To aid in diagnosis, it is recommended to use pulmonary embolism predictive tools such as the Wells score and the revised Geneva score. The level of probability allows you to either go towards a dose of Plasma D-Dimer, followed by a scanner if the result is positive, or straight towards a scanner.

Consider multiple causes

Since the causes can be varied, Dr. Markarian to reassess patients if symptoms persist. For example, re-ultrasound of the lungs should be considered if a patient still has wheezing dyspnea clearly associated with heart failure three hours after ingestion of diuretics following observation of B-lines. »

Another common association: COPD and pneumopathy. “The pleuropulmonary ultrasound then has a great interest” in the detection of pneumopathy. If pneumopathy is ruled out, COPD-related pulmonary embolism should be considered if symptoms persist. Then a chest CT angiography is recommended.

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