The Department of Health is warning of severe disruption to supplies of a life-saving kidney treatment used for intensive care patients with Covid-19.
The three main companies which supply the NHS in the UK are reporting limited supplies, and trusts are being asked to minimise use wherever possible.
The government says a recent surge in demand is to blame.
Almost 30% of patients with Covid-19 on ventilators require this type of treatment, the latest UK data suggests.
The treatment, known as haemofiltration, is a delicate process which mimics the kidney, by continually cleaning the blood of toxins and rebalancing it with, for example, electrolytes.
The technique requires a very specific range of kit and fluids to work.
But during the pandemic, more seriously ill patients are experiencing blood clots which