Unfortunately, there are multiple differential diagnoses for circulatory failure, and several different classifications systems (Table 1). These factors create challenges for junior clinicians working in the ICU and hospital wards in learning about clinical assessment, formulation of provisional diagnoses, and, in particular, assimilation and formulation of information to communicate with more senior clinicians. Delays in recognition and management of circulatory dysfunction can contribute to patient morbidity and mortality. 3, 4, 5
We present here the key teaching points of a simplified four-step model used in our hospital to teach junior clinicians about the steps in assessing the adequacy of the circulation, hypo- and hyperdynamic states, and parameters that may cause concern. This model is aimed at hospital medical officers, junior registrars, and junior nurses. It is delivered as an interactive teaching session (available on request) where participants provide the content to the tables in response to questions (Online Appendix, table 1). The level of detail regarding monitoring devices is tailored to the clinician seniority.
The four-step model involves:
- Measuring the blood pressure (pressure). Blood pressure is measured (in mmHg) in reference to atmospheric pressure and can be measured invasively or non-invasively.
- Estimating the cardiac output (flow). The stroke volume (mL/beat) and cardiac output (L/min) can be estimated clinically and with a variety of devices (Online Appendix, table 2).
- Evaluating end-organ perfusion. End-organ perfusion is evaluated using clinical assessment, laboratory investigations (in particular, renal and liver function), and monitoring devices (Online Appendix, table 2).
- Assessing filling status. If blood pressure, cardiac output or end-organ perfusion are abnormal, the filling status is then assessed clinically and with monitoring devices (Online Appendix, table 2).