The couple posed for photos with the youngsters, played games and autographed CDs during their charity visit last week.
© Rex Features / Buzz Foto
Staff at the hospital, where Kardashian has volunteered for several years, greeted the pair with two giant welcome cards.
Taking to Twitter afterwards, Kardashian praised "the incredible doctors and nurses" she had met for their "hard work".
"The kids there are so brave," she wrote. "They are smiling, sweet and happy despite their circumstances and being around them is truly inspiring."
Kardashian recently opened up about her relationship with West, admitting that she "falls in love fast".
"I've always believed in love," she said. "I haven't always been so lucky, but I still do believe in it."
