Trial Design and Randomization
STAGGERED
Randomization and treatment assignment followed an unbalanced, cluster-randomized crossover design with staggered start dates from November 18, 2015, to March 26, 2018. The unit of randomization was the ED and the treatment allocated was the modality of consultation (T for telemedicine or P for telephone). Participating EDs were randomized to 1 of the 4 unbalanced (3:1) crossover treatment assignment sequences, each consisting of a 6-month period for 2 years: PTTT, TPTT, TTPT, or TTTP. We chose an unbalanced design for this pragmatic trial because we anticipated that telemedicine would not be used in all assigned circumstances as well as the expectation of an intracluster (ED) correlation of 2% or greater.Prior to trial initiation, there was a 6-month study ramp-up period during which protocol and telemedicine training was conducted at all participating EDs. Subsequently, at the start of the trial, participating sites were randomly allocated the consultation modality for each subsequent 6-month period. During this period, the UCDCH pediatric critical care physicians providing the consultations were made aware of the ED allocation assignments in several ways. First, stickers with ED assignments were placed on the cards used by physicians to document consultations; second, emails were sent to all physicians with every change in ED allocation; and third, signs were displayed at all pediatric critical care physician workstations at the UCDCH. Deviating from protocol (ie, using telephone consultation when randomized to telemedicine or vice versa) could occur at the discretion of the referring and/or consulting physician. Research staff, participating physicians, patients, and their families were not blinded to treatment assignment.