Minister of Science and Technology Jorge Arreaza and Attorney General Cilia Flores remained in Havana. Together with Fidel and Raul Castro, they're monitoring Chavez's condition.
Maduro said surgery "was complicated, difficult and delicate, which tells us that the post-operative process is going to be complicated and difficult."
"We shall be in regular contact with the medical teams, always with the objectivity which must guide the management of this situation."
He added that before leaving for Cuba, Chavez called on Venezuelans "to be serenely prepared to confront these hard, complicated and difficult days which it has befallen us to experience, and they can only be confronted with the unity of the people, the political and social forces of the revolution, and men and women in the street."
He urged opposition elements to halt their speculation, lies and vitriol. Referring to Sunday's gubernatorial and legislative elections, Maduro said Venezuelans "are more united than ever spiritually and politically in loyalty to Chavez and our people."
During surgery, internal bleeding occurred. It was corrected. Mayo Clinic cancer expert, Dr. Julian Molina, said it's not unusual when surgery to remove malignant tissue occurs multiple times in the same place.
On Thursday, Chavez improved. Maduro said his condition changed from "stable to favorable."
"That allows us to continue saying that there is growing recovery in (his) situation," he added. Prayer vigils continue for his recovery. Uncertainty prevails. Venezuelans hope for the best.
Proper care, love, inner strength, and time are nature's best healers. Hopefully in combination they'll restore Chavez to full health.
Venezuelan television aired video opening with him saying "I am no longer myself. I am the people." Venezuelans of all ages followed, adding "I am Chavez."
Other programming showed him singing folk songs with supporters and reciting poetry. Venezuelans express justifiable concerns. They pray. They hope for the best. In the fullness of time they'll know.
Chavista politician/academic Aristobulo Isturiz said "as we pray, we should be ready to turn our sadness and pain into a force that can mobilize the people."
It's unclear if Chavez can return for his January 10 inauguration. Constitutional law requires new elections if he's not back within 30 days.
Information Minister Ernesto Villegas said Venezuelans "should be prepared to understand" whatever happens. "It would be irresponsible to hide the delicacy of the present moment and the days to come."
It's unconscionable not to pray for his full recovery. He's too important to lose. More than Venezuela is at stake.