[Answer] A pale and very sleepy but arousable 3-year old child with a history of diarrhea is brought to the hospital. Primary assessment reveals a respiratory rate of 45/min with good breath sounds bilaterally. HR is 150/min BP is 90/64 and SPO2 is 92% on RA. Capillary refill is 5 seconds and peripheral pulses are weak. After placing the child on a NRB with 100% O2 and obtaining vascular access which is the most appropriate immediate treatment for this child?