Ultrasound diagnosis of an acute dyspnea

Introduction

Acute dyspnea is a typical emergency situation. The usual tools (physical examination, radiography) can sometimes be insufficient. Although 1) ultrasound is rarely performed in emergency by the physician, and 2) lung is considered out of reach of the ultrasound field, we have studied its potential to provide an adequate diagnosis, at the bedside.

Patients

This prospective study initially included 74 consecutive patients seen for acute dyspnea and referred to the intensivist by a senior (ER, prehospital setting). Fourteen patients where no definite diagnosis was made were subsequently excluded. Sixty patients were thus enrolled (27 women and 33 men, mean age 73 years, range 22–91 years). The patients had cardiogenic pulmonary edema (n = 16), acute pneumonia (n = 16), exacerbation of chronic obstructive pulmonary disease (n = 11), severe asthma (n = 7), pulmonary embolism (n = 6), pneumothorax (n = 2) and substantial pleural effusion (n = 2).

Methods

The 'initial diagnosis' was the diagnosis made by the senior using clinical examination and basic tools like bedside radiograph, before admission of the patient to the ICU. The 'ultrasound diagnosis' was a diagnosis made after studying six items and establishing an 'ultrasound profile'. Lung sliding, comet-tail artefacts of the type 'lung rockets' (i.e. interstitial syndrome), alveolar consolidation, pleural effusion (with quantitative approach), left ventricle and venous status were included. 'Initial diagnosis' and 'ultrasound diagnosis' were compared together. The gold standard was the diagnosis concluding the hospitalisation report. The patients were analysed with a small ultrasound unit Hitachi-405 equipped with a 5 MHz probe without Doppler, by an intensivist trained to emergency general ultrasound. The whole examination took less than 5 min. This study did not consider the ability of decreasing delay for adequate treatment.

Results

Ultrasound was possible in all patients (i.e. a feasibility of 100%). All in all, the initial diagnosis was correct in 31 cases (i.e. 51% of cases). The ultrasound diagnosis was correct (allowing appropriate management) in 51 cases (i.e. 85% of cases).

The number of cases in which ultrasound gave the correct diagnosis in a patient with a wrong initial diagnosis was 24. The number of cases in which ultrasound led to a wrong diagnosis in patients whose initial diagnosis was correct was four. In 32 cases, ultrasound was not contributive (27 cases whose initial diagnosis was correct, and five cases in whom both initial diagnosis and ultrasound diagnosis were in failure).

Conclusions

Taking into account ultrasound items using simple methods provided an accurate diagnosis of acute dyspnea in 85% of cases, versus 51% with the traditional methods. The ultrasound approach checked lungs, heart and veins like a stethoscope. Obviously, the physician's accuracy will be enhanced by integrating clinical and paraclinical data. In conclusion, this method should contribute to quicker diagnosis, resulting in decreased costs, and above all quicker relief of dyspneic patients.