Circulatory Assessment
Arterial line/invasive blood pressure monitoring
An arterial line provides continuous blood pressure monitoring, and facilitates blood gas sampling to track response to therapy.
A swing in the waveform with respiration can suggest under-filling. Invasive cardiac output monitoring can be established via an arterial line (e.g. LiDCO), usually once on the intensive care unit.
Central venous access
This is often obtained early, as it gives reliable, central access for the continuous infusion of drugs. Central venous pressure (CVP) readings can be taken pre- and post-fluid challenges to add to the clinical interpretation of fluid status in the patient.
Most patients post-ROSC should have a central line and arterial line sited if they are felt to be suitable for ongoing resuscitation/intensive supportive care.
Echocardiography
This gives a visual guide to the filling status and the cardiac index of the patient, allowing as ejection fraction estimation to be made. It may also be used to assist in establishing the aetiology of the cardiac arrest: the existence of regional wall abnormalities (in combination with ECG changes) may point towards a primarily cardiac cause, whereas a dilated right ventricle may suggest PE as the underlying cause.
It can be useful early in the management of a patient with ROSC, both diagnostically and by guiding fluid and inotrope/pressor therapy.
However, a suitably skilled clinician must be available to perform and interpret sonographic images.
Non-invasive cardiac output monitoring
Although there is no patient-orientated evidence supporting its use in the emergency department, non-invasive cardiac output monitoring can be rapidly and easily instigated (e.g. via oesophageal or suprasternal doppler) and adds further data aiding circulatory assessment and management.
Inotropes and vasopressors are often needed to maintain blood pressure and cardiac output. Choice of inotropic support is beyond the remit of this session, but depends upon the underlying pathology.