NBC has seen enough good numbers for “Chicago Med” to order five additional episodes of the hospital drama, bringing the show’s first-year total to 18.

Though four telecasts, “Chicago Med” averaged a 2.0 rating in adults 18-49 and 8.9 million viewers overall, according to Nielsen’s “live plus same-day” estimates. Thanks in part to its potent lead-in from “The Voice,” it has won its Tuesday 9 p.m. time period in the demo every week.

Because of its late start (Nov. 17), NBC won’t need 22 or 24 episodes of “Chicago Med” to make it through the rest of the season, as it will have 14 episodes available to air January through May.

“Chicago Med” is the third program of the Dick Wolf “Chicago” trilogy of dramas, joining “Chicago Fire” and “Chicago PD” on the network’s schedule. The series will have a three-show crossover storyline early in January.