Ava Passley covered her nose and giggled as Dr. Jacob Hen walked into an examination room at his pediatric pulmonology office in Trumbull recently. Ava, 3, of Bridgeport, knows what to expect from a visit with Hen, having dealt with asthma since she was 1. She also spent several nights in the hospital after an attack in 2012. “I had always heard about wheezing, but had never really heard it before that,” her mother, Beverly Passley said. Ava is part of growing number of people in Connecticut who have used the emergency room for asthma symptoms, according to the most recent figures from the state Department of Public Health.