On 12/20/2020, dad of patient called our office after hours. Nurse triage line took the call. Dad's reported that pt had a fever of 100.6 F (max temp) and hard stools. Pt was given a dose of Tylenol and 10-15 minutes later, pt vomited. Triage nurse advised that dad follow up with PCP office when open in the AM.  Dad called our office at 10:25am on 12/21/2020 stating that pt fever had lifted, but pt vomited a total of 5 times since the night before, with the last episode at 7:45 am on 12/21/2020. Pt had adequate fluid intake and urine output and stool had softened. MA advised continued home care. Appropriate triage advice was given and documented. At 16:43(pm) on 12/21/20, dad called back to clinic stating patient symptoms had worsened and they were at the emergency department. Dad disconnected call before speaking with the MA. The MA attempted to call dad back, but there was no answer. A message was left for dad to return call. On 12/22/20 at 12:44(pm), dad called in to clinic to report that pt had died- cause unknown. Our clinic obtained records from Hospital. The ED report stated that pt presented to the emergency department via EMS Code 3 in cardiac arrest. Unknown downtime prior to the initiation of chest compressions. Pt was staying with grandparents. When grandma went to wake pt from his nap, he was not responsive. When grandma tried to pick him up, there was possibly some brief, generalized seizure activity as well as coughing and gagging. Child remained unresponsive and was taken by private vehicle to outside Urgent Care where pt was found to be apneic and in asystole. An AED was applied, no shock advised. EMS was called and CPR was started. EMS placed an endotracheal tube and established IO access. 4 rounds of epinephrine were administered during the course of the prehospital resuscitation which was approximately 15-20 minutes. Presenting rhythm was asystole. No change in rhythm upon transport and arrival. Immediately upon arrival the pediatric transport team was activated and the pediatric intensivist was paged. Chest compressions were resumed according to protocol. Additional inter osseous access was established in the left proximal tibia. Fluid bolus was initiated. Serial doses of epinephrine were administered every 4 minutes throughout the resuscitation. The child also received several boluses of IV bicarb. Online consultation by ED physician with PICU attending was established early in the resuscitation course. It was agreed by ED physician and PICU attending that the peds transport team would be dispatched urgently to the ED location in anticipation of possible ROSC and need for emergent transport to PICU. It was agreed by ED physician and PICU attending that transportation would not be initiated with the child still undergoing resuscitation requiring chest compressions prior to ROSC. Initially, endotracheal tube position felt to be acceptable based on the clinical evaluation, however chest x-ray did demonstrate some degree of right mainstem intubation, after which the tube was pulled back approx 2cm and subsequent x-ray showed the ETT tip in good position approx 1 cm above the carina.  Initial end-tidal CO2 was 14 on arrival, this continued to trend downward until undetectable throughout the course of the resuscitation. At no point were there palpable pulses or other evidence of return of circulation throughout the resuscitation. Capillary blood glucose was initially undetectable. The child received serial boluses of D 25 via IO line for a tital of 30 g dextrose after which CBG ultimately came up to 244. Multiple efforts were made throughout the resuscitation to achieve IV access and to obtain blood for laboratory studies. All efforts were unsuccessful, making it impossible to obtain any labs throughout the course of the resuscitation. Attempts to obtain even capillary blood samples via heel stick for CBG measurements were extremely difficult. Resuscitation continued for 49 minutes after ED arrival. A total of at least 65 minutes of CPR time. Bedside ultrasound was used to look for cardiac activity during the last 5 pulse checks of the resuscitation, demonstrating cardiac standstill. Despite the efforts and interventions mentioned, ROSC was never obtained and the code was discontinued at 17:03(pm). The child's parents were informed of his death upon their arrival to the ED at approximately 17:40(pm). Family was given time with the pt. The medical examiner arrived and discussed case at 19:11(pm). At 19:49(pm) Medical Examiner was interviewing grandparents along with 2 County Detectives. The medical examiner took custody of the pt at 21:52(pm). Evidence bag was sent with the medical examiner.  Pt received vaccinations 10 days prior to death. We are still waiting for M.E. report, as we do not have any further information as to why pt passed.