Wells’ score for early prehospital screening of pulmonary embolism

Pulmonary embolism (PE) represents a signi fi cant health problem due to non-speci fi c clinical features and a high risk of lethal outcome. PE diagnostics can some-times be very di ffi cult, especially at the prehospital level. We present a patient in whom early screening for PE at the pre-hospital level, performed using the Wells’ Score, was a life-saving event. Case scenario: the Emergency Medical Service (EMS) received a call regarding a male, aged 27 years, who was unconscious. Prior to losing consciousness, he complained of su ff ocation and tachycardia. Ten days earlier he sustained an injury to the knee which was immobilized with a splint, followed by bed rest. A year ago he was examined for chest pain, hypertension and tachycardia. On examination the patient was conscious, well oriented, eupneic, afebrile, with normal skin color. On pulmonary auscultation breath sounds were normal, and oxygen saturation was 90%. Findings on cardiac examination included: regular rate and rhythm, no murmur, blood pressure (BP) 120/85mmHg on both arms. ECG revealed sinus rhythm, rate of 100 beats/min, discreet signs of right heart strain (S1Q3T3 pattern), negative T wave from V1-V4, ST depression in D2, D3, AVF. A Wells’ score of 6 (most probably PE) was calculated: immobilization for 4 weeks – 1.5 points, tachycardia (pulse 120/ min) – 1.5 points and alternative diagnosis less probable than PE – 3 points. Th e patient was suspected of PE and referred to a cardiologist. Conclusion. Pulmonary embolism o ft en remains undiagnosed during a patient’s lifetime or is erroneously diagnosed. Th e signi fi cance of the scoring of each patient aimed at the recognition of pulmonary embolism at the prehospital level cannot be underestimated.


INTRODUCTION
Acute pulmonary embolism (PE) is a potentially life-threatening emergency situation, involving obstruction of the pulmonary artery or arteriole.The annual incidence of PE is 100-200 cases per 100,000 inhabitants, with the assumption that this number is even higher because the disease often remains undiagnosed during a person's life-time.In 25-30% of cases the signs of new or old PE are detected only on autopsy.(1) As people over 40 years of age are at a higher risk of the development of PE than young people, and as the risk may be approximately doubled with every next decade of life, it is expected that in the future an increasing number of patients will be diagnosed with PE.
Clinical features of this disease are variable, ranging from no symptoms to sudden death as the first and only presentation of PE.Up-to-date European Society of Cardiology (ESC) Guidelines (from 2014) on the diagnosis and management of acute pulmonary embolism define diagnostic criteria for the clinical confirmation of PE and criteria for the exclusion of PE.
According to its clinical manifestation, PE is classified as massive, sub-massive and non-massive.Most small pulmonary embolisms occur asymptomatically.Larger emboli cause dyspnea, pleural pain, rarely cough and hematochezia.Massive emboli lead to hypotension, circulatory collapse and heart failure.
Because most patients ultimately die within the first hours of presentation, early diagnosis is of paramount importance.At the prehospital level, except for ECG findings, the clinical probability for PE can be assessed by the application of scoring systems based on anamnestic data, clinical features and risk factors.The simplest one is the Wells' Score (table 1).( 2) The sum of 0-1 points implies a low, 2-6 points a moderate and over 7 a high clinical probability of PE.Pulmonary embolism is hardly probable if the score value is 4 and lower, and probable if the score is higher than 4 points.
We are presenting a case of early PE recognized at the hospital level by using the Wells' Score.

CASE PRESENTATION
The Emergency Medical Service (EMS) was dispatched after a first line priority call was received regarding a 27-year old male who was unconscious, as stated by an eye-witness.Prior to the loss of consciousness, the patient had a feeling of suffocation and tachycardia.Seven days earlier, during training, he sustained an injury to the knee that was immobilized by a splint and followed by bed rest.A year ago he was examined for chest pain, hypertension and tachycardia.On examination the patient was conscious, well oriented, eupneic, afebrile, with normal skin color and visible mucosa.The left lower limb was immobilized with a splint, and was of a somewhat bigger circumference than the right one, with preserved peripheral pulses.
Score systems were developed which became especially applicable in EMS due to the need for defining exact parameters for triage of PE patients.The standardized Wells' Score (2) was the simplest and most applicable in the Emergency Department.In the reported case, a Wells' Score of 6 was obtained (high probability of PE).This supported the decision regarding the application of oxygentherapy and urgent transport to a cardiac care facility.Beside the Wells' Score, a revised Geneva Score is also in usage.A comparison of these two tests concluded that the Wells' Score was of higher sensitivity in the early screening of PE. (9)CONCLUSIONPulmonary embolism is not frequently diagnosed during a patient's life-time.The application of the Wells' Score can be helpful in the early prehospital screening of PE.
(5)Brain natriuretic peptide (BNP) (291, upper lim-Imminent clinical assessment of the presence or absence of hemodynamic compromise allows the classification of patients into a high risk group or the group which is not at high risk.This classification of patients with a suspected PE helps in the choice of optimal diagnostic and initial therapeutic options.The evaluation of "clinical probability" is based on predisposing factors, as well as signs and symptoms detected in the patient.Although individual in each patient, according to Pollack et al., in EMS the initial symptomatology of PE involves dyspnea, chest pain, presyncope or syncope, tussis and/ or haemoptysis.(5)Thedataonsyncope as the predecessor of PE is reported not only in our manuscript but also in papers of other authors.(6)Other symptoms of PE are suffocation, tachycardia, rapid feel-