"We're overwhelmed, overwhelmed. We lack everything: personnel, equipment and medicines," he said.
Ambulances pulled up outside the hospital every five to 10 minutes, also bringing in wounded loyalists.
"We can't go on at this rate. We are losing people who in normal times we would be able to treat," said exhausted surgeon Mahmud Mohammed, as explosions and gunfire echoed from the streets.
Misrata, where the general hospital is in the hands of regime loyalists, has been the scene of deadly urban guerrilla fighting between the regime and outgunned rebels for more than six weeks.
Saturday's upsurge came after Kadhafi's government said it had given its army an "ultimatum" to stop the rebellion in the city, 200 kilometres (120 miles) east of the capital.
Deputy Foreign Minister Khaled Kaim said: "There was an ultimatum to the Libyan army: if they cannot solve the problem in Misrata, then the people from (the neighbouring towns of) Zliten, Tarhuna, Bani Walid and Tawargha will move in and they will talk to the rebels.
"If they don't surrender, then they will engage them in a fight," he told journalists.
However, the impact of such a move was unclear as militia "volunteers" were already believed to be among regime forces in Misrata.
And Hamed al-Hasi, a colonel coordinating rebel fighters at the western gate of the crossroads town of Ajdabiya in the east, said such an announcement would signal the insurgents were beginning to win the battle for Misrata.
"This is the first nail in the coffin of Kadhafi. This means the Libyan army is no longer capable," he told AFP.
Omar Rajab, a 29-year-old rebel, said tribal fighters in plain clothes had joined the loyalist forces in Misrata, saying they "come from tribes in the south."
The United States carried out its first Predator drone strike in Libya on Saturday, the Pentagon said, declining to give details on the targets or location.
However, a NATO statement said a "regime Multiple Rocket Launcher (MRL) in the vicinity of Misrata," was destroyed in the strike.
"The MRL has been used against civilians in Misrata," it said. "NATO has kept up a high operational tempo -- over 3,000 sorties since we took full command of the mission, almost half of them strikes.
"We have struck a broad range of targets across the country -- tanks and rocket launchers, armoured vehicles and ammunition stores, command and control sites."
On Friday, as anti-aircraft fire rang out and ambulance sirens wailed in the capital, NATO air strikes hit a patch of bare ground looking like a bunker opposite Kadhafi's Bab al-Aziziya residence in the centre of the capital.
Authorities who took foreign correspondents there on Saturday said they were "a parking lot" and "sewers."
Later on Saturday, several explosions rocked the capital as NATO warplanes overflew Tripoli.
The official JANA news agency reported two people died in NATO raids late Friday on the Zintan region, southwest of the capital, scene of heavy fighting between government forces and rebels who hold several towns.
Kaim accused Washington of "new crimes against humanity" after US President Barack Obama authorised the deployment of drones over Libya for what his administration called "humanitarian" reasons.
He also hit out at a senior US senator's visit to Benghazi, the rebel capital in the east, saying the Transitional National Council did not represent Libyans and had "no authority on the ground."
John McCain, a Republican senator who lost the presidential race to Obama in 2008, earlier held talks with TNC leaders, urging the international community to arm and recognise the rebel body.
The US military's top officer, Admiral Michael Mullen, said on Friday that allied air strikes had already destroyed 30 to 40 percent of Kadhafi's forces, sending the conflict toward a stalemate.
France, Italy and Britain have said they would send military personnel to eastern Libya, but only to advise the rebels on technical, logistical and organisational matters and not to engage in combat.
Two French Mirage fighters taking part in the NATO operations made an emergency landing in Malta on Saturday after one developed a fault in its hydraulic system, aviation officials said. Both aircraft landed safely.
On the humanitarian front, the Red Cross warned the situation in Misrata could "rapidly deteriorate further and the lack of basic services such as water, electricity, food and medical care could turn critical."
And on Saturday, an aid ship delivered 160 tonnes of food and medicine to the port city before it evacuates around 1,000 stranded refugees.
Hundreds of Libyan families lined up along the harbour front in hope of getting on board the vessel chartered by the International Organisation for Migration, which has already transported 3,100 refugees from 21 countries out of the besieged city.
But Dakir Hussam, a Syrian electrician, expressed his delight at managing to get a place on the Red Star One.
"Kadhafi's men shoot at anything that moves in the city, but they are also suffering a lot," he said, referring to the burial he saw of up to a dozen loyalist fighters this week.
The UN refugee agency says about 15,000 people have fled fighting in western Libya into Tunisia in the past two weeks and a much larger exodus was feared.
Three people who escaped the violence in Libya were killed and 72 hurt on Saturday when their truck overturned in northern Niger, that country's state radio reported.
Massive Libyan protests in February -- inspired by the revolts that toppled long-time autocrats in Egypt and Tunisia -- escalated into war when Kadhafi's troops fired on demonstrators and protesters seized several eastern towns.
The battle lines have been more or less static in recent weeks, however, as NATO air strikes have helped block Kadhafi's eastward advance but failed to give the poorly organised and outgunned rebels a decisive victory.