COVID-19 Challenging Cases
Experience with two patients highlights the importance of understanding fluid status
A presentation by Critical Care luminary Professor Mervyn Singer of University College Hospital, London, contrasts two cases which underline the importance of having the most accurate haemodynamic diagnostics on hand.
As Prof Singer states, while COVID-19 yields a high proportion of classic ARDS-type patients, the disease is also associated with more thrombosis and pulmonary embolus than a typical respiratory condition. Indeed only 13% of post-mortems showed no pulmonary vascular problems.
Pulmonary vascular problems are associated with pulmonary hypertension, right ventricular strain and right ventricular failure. These conditions point to the importance of understanding the origins of a patient’s fluid problems. In other words, while it’s all about fluid, it’s not always about giving fluid.
So to the two case studies, full details of which can be found in the presentation. Both patients presented with similarly compromised fluid status, as evidenced using oesophageal Doppler monitoring (ODM). In both cases cardiac output was poor, leading the clinical team to shortlist the causes then “fluid challenge” them with passive leg raise. In the first patient this worked well and satisfactory circulatory status was achieved after repeated and careful ODM-controlled titration of 250ml fluid boluses. However in the second patient, while hypovolaemia was again apparent, its cause was less easily diagnosed. The patient was not fluid-responsive, suggesting other reasons for left ventricular underfilling. The clinicians needed to rule out other factors, including whether the ventilator settings might be preventing blood flow to the left ventricle. By decreasing the PEEP it became quickly apparent that this was indeed the issue.
The learning point here is that understanding fluid status and responsiveness is vitally important, even if only to rule out the option of just giving fluid. And the better the window into this world, as provided by the most accurate, real-time haemodynamic monitoring technology, the better equipped the clinical detectives are to reach the right conclusion.
Our sincere thanks to Prof Singer for sharing this insightful presentation.
