Trehan and his close associates had to fight their way inside the healthcare institute with the help of the police.
On arrival at Escorts, Trehan was permitted to enter the premises but his key aides Jugal Sharma and K S Sehgal were stopped at the gates by the security personnel.
There were ugly scenes at the hospital as a scuffle broke out as irate relatives of patients protested the delay in operations by Trehan, who managed to enter the hospital with his aides under police escort.
The new management at Escorts Heart Institute and Research Centre, which was bought by Ranbaxy-promoted Fortis Healthcare in 2005, stuck to the ground that the dismissed employees will not be allowed entry into the hospital.
Meanwhile, police filed an FIR against Trehan and others at the New Friends Colony Police Station for vandalism and trespass at the Escorts Hospital on the basis of a complaint by Fortis Healthcare on Saturday, a day after his ouster.
"He (Trehan) fully understands the implications of all this," Daljeet Singh, President Operations of Escorts Heart Institute and Research Centre told reporters here on Tuesday.
Singh claimed the Escorts management was complying with the Delhi High Court order which "does not mention anything about his (Trehan's) associates."
"They do not have any technical skills and only take care of secretarial work," Singh said.
Singh said Escorts management has asked the police to help maintain law and order, and peace in the hospital premises. "There are many employees in Escorts who can take care of that work."
A High Court order had on Saturday had given Trehan unrestricted access to the hospital.
When asked about possible arrest of the two employees, he said, "we have approached the police and it is up to them to ensure law and order."
Fortis Healthcare on Friday had sacked Trehan as Executive Director of Escorts Heart Institute and Research Centre citing conflict of interest as the cardiologist was "pursuing his pet Medicity project in neighbouring Gurgaon."
The standoff took a murkier turn as Fortis Healthcare Limited Managing Director Shivinder Mohan Singh accused Trehan of siphoning off funds from Escorts for his Medicity project.
Trehan denied the charges and hit back at Singh saying that he had "drained the coffers of Escorts" by spending "a fortune" on building an office for himself within the hospital premises.
Trehan has not been allowed to take new patients at Escorts Hospital since his ouster on Friday but has been allowed to operate and attend to patients who had been granted appointments till May 19.
He has also been allowed to perform surgeries on patients who are awaiting surgery or who may have paid fees or deposited money, donated blood or incurred any cost in EHIRC for the reason that they were to be operated by Trehan.
Fortis had acquired 90 per cent stake in EHIRC in 2005 from Rajan Nanda for Rs 585 crore. Trehan continues to hold 10 per cent stake in Escorts.