Syncope. We need a prehospital pathway.

Non traumatic Transitory Lost Of Consciousness (TLOC) is a common cause of medical emergency call. Among TLOC Syncope is the most common cause. So the first challenge for an emergency professional is discerning from Syncope and non syncope situations (seizures, psychogenic, other rare causes).

2018 ESC Guidelines for the diagnosis and management of syncope

Syncope according to 2018 Guidelines definition is a “TLOC due to cerebral hypoperfusion, characterised by a rapid onset, short duration, and spontaneous complete recovery”. 

Among Syncope the causes can be found in vagal reflex (Reflex syncope), a drop in blood pressure due to a deficiency of compensation in a standing position (Orthostatic syncope) and a cardiac cause of syncope (Cardiac syncope)

2018 ESC Guidelines for the diagnosis and management of syncope

But what is the role and what can and must be done on the prehospital field to understand treat and risk stratify a Syncope?

Anamnesis

Is a fundamental step to understand and risk stratify a syncope episode. It has to be targeted to collect all the important informations and to don’t loose precious time.

We can divide the information we collect in two categories.

The first kind of information we area going to ask (to bystanders and patients) is about the syncope event.

• How much the lost of consciousness lasted
• How it happened (standing, sitting or laying)
• What was the patient doing (resting or during exercise)
• What the patient felt before the syncope (palpitations, chest pain, dyspnea, dizziness, other)
• What happened during or immediately after the syncope (seizures, other)

Second step is collecting informations about the patient medical conditions. We have to focus on

• What medical condition he actually suffers or suffered in the past
• Which kind of drugs he is actually doing

After a focus anamnesis the second step is about the physical exam of the patient.

Diagnostic tests

During physical exam a rapid general neurologic and cardiac examination has to be completed, but two additional steps need to be done in a syncope patients

• Orthostatic challenge in active standin position
• Carotid sinus massage (CSM) in patients aged >40 years.

Orthostatic challenge:  Standing BP evaluation has to be done after 3 minutes of active standing position with the patient fully monitored, and “abnormal BP fall is defined as a progressive and sustained fall in systolic BP from baseline value >_20 mmHg or diastolic BP >_10 mmHg, or a decrease in systolic BP to <90 mmHg” (European Society of Cardiology 2018 ESC Guidelines for the diagnosis and management of syncope).

Carotid sinus massage: A ventricular pause lasting >3 s and/or a fall in systolic BP of >50mmHg is known as carotid sinus hypersensitivity. “Carotid sinus syndrome (CSS) There is strong consensus that the diagnosis of CSS requires both the reproduction of spontaneous symptoms during CSM and clinical features of spontaneous syncope compatible with a reflex mechanism.” (European Society of Cardiology 2018 ESC Guidelines for the diagnosis and management of syncope)

12 leads EKG

It’s a fundamental diagnostic tool and has to be performed in all syncope patients.

What are the risky features we have to consider when looking to ann EKG of a syncope patients:

At least 6:

1. Ischemia
2. Arrithmia
3. Pre-excitation/WPW
4. Brugada pattern
5. Hypertrophic cardiomyopathy
6. Arrhythmogenic Right Ventricular Cardiomyopathy

POCUS

Is there a role for Point of Care Ultrasound in differential diagnosis and risk stratification of syncope.

Probably yes cause we can look at:

• Aorta for dissection
• VD/VS ratio for PE
• Pericardium for effusion
• EF for cardiac function evaluation

High risk VS non high risk syncope

At the end of those steps the prehospital professional has two chances.

1. There is a likely cause of syncope
2. The syncope is of unknown cause

2018 ESC Guidelines for the diagnosis and management of syncope

If the cause is known or very likely we have to follow the specific pathway.

In the unknown syncope we have to stratify the risk.

In prehospital field is important to look for high risk features of syncope:

• History of heart failure or other cardiac conditions
• Syncvope in supine position
• Syncope during excercise
• Dyspnea before or immediately following syncope
• Palpitations before syncope episode
• EKG abnormalities
• Persisting low blood pressure (SBP<90 mmHg) in supine positi
• Orthostatic Hypotension

Each one of those is indicative of high risk prehospital features and the patient need further ED examination.

In all other cases the clinician can decide case by case if the patient can be treated out of the hospital or need admission to ED.

References :

Michele Brignole, Angel Moya et al. European Society of Cardiology 2018 ESC Guidelines for the diagnosis and management of syncope