Dr Oleh Duda was in the middle of a particularly complicated surgery at a hospital in Lviv, Ukraine, when he heard explosions nearby. Moments later, the lights went out.

Duda had no choice but to keep working with only a headlamp for light. The lights came back when a generator kicked in three minutes later, but it felt like an eternity.

“These fateful minutes could have cost the patient his life,” the cancer surgeon told The Associated Press.

The operation on the patient’s major artery took place November 15, when the city in western Ukraine suffered blackouts as Russia unleashed yet another missile barrage on the power grid, damaging nearly 50 per cent of the country’s energy facilities.

The devastating strikes, which continued last week and plunged the country into darkness once again, strained and disrupted the health care system, already battered by years of corruption, mismanagement, the COVID-19 pandemic and nine months of war.

Scheduled operations are being postponed; patient records are unavailable because of internet outages; and paramedics have had to use flashlights to examine patients in darkened apartments.

The World Health Organization said last week that Ukraine’s health system is facing “its darkest days in the war so far,” amid the growing energy crisis, the onset of cold winter weather and other challenges.

“This winter will be life-threatening for millions of people in Ukraine,” the WHO’s regional director for Europe, Dr Hans Kluge, said in a statement.

He predicted that 2 million to 3 million more people could leave their homes in search of warmth and safety, and “will face unique health challenges, including respiratory infections such as COVID-19, pneumonia and influenza.”

Attacks have hit hospitals and outpatient clinics in southeastern Ukraine, too. The WHO said in a statement last week that they have verified at least 703 attacks between February 24, when Russian troops rolled into Ukraine, and November 23.

The Kremlin has rejected accusations that it targets civilian facilities. Kremlin spokesman Dmitry Peskov once again insisted last week that Russia is targeting only sites “directly or indirectly related to military power.”

But just last week, a strike on a maternity ward in a hospital in eastern Ukraine killed a newborn and heavily wounded two doctors. In the northeastern Kharkiv region, two people were killed after the Russian forces shelled an outpatient clinic.

In Lviv, Duda said the explosions were so close to the hospital that “the walls were shaking,” and doctors and patients had to go down to the shelter in the basement — something that happens every time an air raid siren sounds.

The hospital, which specializes in treating cancer, performed only 10 out of 40 operations scheduled for that day.

Health Minister Viktor Liashko said on Friday that there are no plans to shut down any of country’s hospitals, no matter how bad the situation gets, but the authorities will “optimise the use of space and accumulate everything that’s necessary in smaller areas” to make heating easier.

Liashko said that diesel or gas generators have been provided to all Ukrainian hospitals, and in the coming weeks an additional 1,100 generators sent by the country’s Western allies will be delivered to the hospitals as well. Currently, hospitals have enough fuel to last seven days, the minister said.

In Kyiv, the majority of the hospitals are functioning as usual, while relying on generators part of the time.

Smaller private practices and dentist clinics, in the meantime, are having a hard time keeping their doors open for patients.