TOKYO >> A treatment used as a “last resort” for severe cases of COVID-19 could soon reach capacity as hospitals across Japan strain to meet the demands of a growing outbreak.

In Japan, 24 patients with severe infections have been treated using extracorporeal membrane oxygenation, or ECMO, a resource-intensive but cutting-edge machine used occasionally to remedy serious lung and heart problems.

There are upwards of 1,300 ECMO machines available in the country. But only about 300 of those are available for treating COVID-19, said Satoru Hashimoto, director of intensive care medicine at the hospital of the Kyoto Prefectural University of Medicine.

“If things get worse, we don’t have enough ECMO machines, and hospitals are already full of patients,” Hashimoto said. “I don’t know what’s going to happen next.”

Hospitals can’t set aside all machines for the coronavirus since the treatment is also used for patients with severe heart and lung issues. Even hospitals with five machines aren’t able to spare any for COVID-19 treatment.

In some cases, hospital resources are being stretched so thin that doctors have had to transfer patients using their own personal cars, Hashimoto said. Health care providers are being forced to make up for the absence of an “ECMO Center” commonly found in other developed countries, he added, as well as a lack of logistical support from local governments.

In February, Hashimoto and a team of health care professionals created ECMOnet, a registry coupled with a 24-hour hotline that allows more than 400 participating hospitals to exchange information, pool resources and, in some cases, transfer patients to a facility where an ECMO machine is available.

The treatment involves running the blood of a patient with respiratory or cardiac failure through an artificial lung.

Nine of the 24 COVID-19 patients treated with ECMO in Japan have recovered completely or have already been weaned successfully onto more conventional treatment methods like oxygen tanks or mechanical ventilators. So far, no patients treated with ECMO in Japan have died.

But while this specialized treatment may be showing promise, other experts say the bigger issue is whether hospitals will be able to cope with the influx of patients seeking intensive care.

About 80% of COVID-19 patients experience mild symptoms while about 15% need hospital-based care, according to the World Health Organization. The remaining 5% require intensive care, and only a small number qualify for ECMO. Even then, ECMO is seen as a last resort — only to be used when conventional methods fail to yield positive results.