This is a multi-site study of how nutrition is delivered to critically ill patients in pediatric intensive care units (PICUs) around the world. Each site will include mechanically ventilated children in their respective PICUs and record the details of what type and amount of nutrition was received. These details will be compared to goals designated by the clinicians caring for each patient. Data will be entered in a secure online remote data capture tool and managed by the lead researchers in Pediatric Critical Care Nutrition at Boston Children's Hospital, Nilesh Mehta, MD and Lori Bechard, PhD, RD. Data will be analyzed to better understand how different types and amounts of nutrition impact important PICU outcomes such as length of stay, ventilator time, incidence of infections, and mortality.

Specific aim 1: To examine the impact of energy and protein adequacy on clinical outcomes.

Specific aim 2: To describe world-wide patterns of nutritional therapies in the PICU.environment: use of guidelines/use of adjuncts (acid suppression, motility, etc.)/glycemic control strategy/etc. To describe these practices in subgroups of: cardiac, surgical, medical, oncology/stem cell transplant patients in the PICU.

Specific aim 3: To examine enteral nutrition practices, including timing, route (gastric vs. post pyloric), adjuncts, and enteral nutrition (EN) intolerance definitions, in PICU patients worldwide Specific aim 4: To examine the current practices around parenteral nutrition prescription during the first week of critical illness in the PICU; time of initiation (early vs. late), rationale, threshold for initiation.

Primary predictor: nutritional adequacy (energy, protein) Secondary predictors: nutritional status, use of guidelines/site level indicators (location, staffing), use of adjuncts (acid suppression, motility, etc.), EN intolerance, subgroups (cardiac, surgical, medical, oncology/stem cell transplant), EN route/timing

Inclusion Criteria:

• Sites with at least 8 PICU beds with the capacity to designate a site-specific clinician for data collection, preferably a clinician with an interest in nutrition or a dietitian, are eligible to participate.
• Patients 1 month to 18 years of age, admitted to the PICU and requiring mechanical ventilation with an anticipated length of PICU stay of 3 days or more.

Exclusion Criteria:

• Sites with < 8 PICU beds and/or no available clinician for data collection
• Subjects < 1 month or > 18 years, PICU length of stay < 3 days, not mechanically ventilated, receiving compassionate care only towards end of life, or enrolled in a nutrition intervention trial

Patients 1 month to 18 years of age, admitted to the PICU and requiring mechanical ventilation with an anticipated length of PICU stay of 3 days or more.