Rick Santorum's Daughter Hospitalized
01/29/2012 AT 02:30 PM EST
Bella, who has a rare, life-threatening genetic disorder called Trisomy 18, was admitted to Children's Hospital of Philadelphia on Saturday.
Santorum's 20-year-old daughter, Liz, appeared on his behalf in Sarasota, giving a brief speech to a crowd of about 250 at an airplane hangar.
"My dad wishes he could be here with all of you today," she said, according to The Palm Beach Post. "My dad today is exercising his most important role; being a dad."
Santorum's campaign said that reality stars Jim Bob and Michelle Duggar of 19 Kids and Counting also would fill in for the former Pennsylvania senator. The GOP primary is on Tuesday.
"Rick himself intends to return to Florida and resume the campaign schedule as soon as possible," his spokesman Hogan Gidley says.
Santorum often has spoken about how he never expected Bella to live to her first birthday. Half of babies born with Trisomy 18 don't survive a week, and those few who live into their teenage years suffer serious medical and developmental problems.