Accidental traumas and injuries are a leading cause for health problems, emergencies , and even death in pediatric population . Diarrhea and vomiting which may lead to dehydration quickly is another concern , in addition to respiratory infections . Very good project I think. 

I would add asthma - especially in children from lower socio-economic demographics. 

Severe pneumonia, AWD with severe dehydration, Acute epiglottitis, Acute Stroke syndrome, Heart failure, respiratory failure, Status epilepticus,acute status asthmaticus, AKI,CKD, POISIONING,HEAD INJURY, SEPTICEMIA,DKA, ELECTROLYTE IMBALANCE,SAM,Dengue hemoragic fever,Rabies,hepatic failure, leukemia, etc

In our tropical environment it is essentially pneumonia, acute diarrhea with dehydration, severe malaria, bacterial meningitis, acute poisoning and accidental pathology,  diabetic ketoacidosis.

Severe Croup, Life threatening Asthma, Burn, Foreign Body leading to Airway Obstruction, Drowning, Anaphylactic Reaction/Shock, Febrile Fit, Status Epilepticus, Bronchopneumonia, Bronchiolitis.

Here are two references if you do not already have them:

American Academy of Pediatrics. Committee on Child Abuse and Neglect; Committee on Injury, Violence, and Poison Prevention: Council on Community Pediatrics. Policy statement - child fatality review. Pediatrics. 2010;126:592-596.

Centers for Disease Control and Prevention. Child Health: mortality. Available at: http://www.cdc.gov/nchs/fastats/child-health.htm. Accessed August 30, 2014.

Foreign body in respiratory tract, Stathus astmhaticus, Status epilepticus,Had trauma, injured child,Poisoning, HUS;Ketoacidosis,Rey sy, Severe pneumonia, heart failure

As mentioned by Jean Kiko diarrhea with dehydration is an important cause of mortality and morbidity. Rota virus may cause severe recurrent watery  diarrea leading to prerenal AKI, which if not recognized early,  may progress to stage V prerenal azotemia( with hemodynamic instability) and intrinsic AKI.

AS for Karmen: HUS is not that common. We see only 1-2 cases per year

Thanks everyone for your input.  You are a great help

In my experience, a few of the most dynamically unstable problems I encounter are (in no particular order)

Status Asthmaticus, Status epilepticus, Foreign Body in the Airway, Bronchiolitis, Dengue Shock Syndrome, Croup, Moderate-severe dehydration, Diabetic Ketoacidosis. In neonates, NEC/Sepsis, & Meconium Aspiration Syndrome - these conditions, I think everyone would agree- make up 80% of our case load.

Darlene,

Your have a really good idea for a thesis.  Since your focus is Rapid Response Team, a more focused question might be "What are the most common unexpected emergencies seen in the hospitalized pediatric population?"

From my ED nurse and CCU Rapid Response Team experience, I would have to say that airway emergencies are likely to be the most common reason for Rapid Response Team activation in the hospital.  I don't however, have any references to cite, but I would suggest that you might find some information and direction by researching in-hospital mortality and morbidity events. 

Good Luck!

From a front door emergency perspective we see a quite few respiratory emergencies ie bronchiolitis and asthma."Flat" or poorly responsive infants due to septic shock from bacteremia/ sever dehydration is less common but another reason. Then there are trauma related cases due to accidents ,neglect or deliberate harm and near drowning which again are less common but in the top reasons for a "crash" response. I am not so sure what happens on the wards but this is my personal experience working in a mixed adult and paediatric ED.