The main purpose of this study is to review the resource utilization of severe adult H1N1 pneumonia undergoing antiviral and oxygen therapy, mechanical ventilation and support with pulmonary rescue therapies ( nitric oxide, ECMO, HFO) in critically ill patients in Winnipeg. Secondary objectives include, comparison of resource utilization to other similar disorders (viral pneumonia, bacterial pneumonia, septic shock, ARDS). The investigators will also look at the percentage of patients that required ICU care as compared to those who could be cared for on medical wards. The investigators will determine the resources used by both groups and compare. Finally the investigators will record the frequency of chronic comorbidities in hospitalized adult H1N1 patients.

Inclusion Criteria:

1. > 18years,
2. Suspected or confirmed influenza (Appendix A)
3. Requirement for ICU admission due to respiratory distress or critical illness defined as one of:a) Inspired oxygen need of >50% for at least 4 hours (For FiO2 for non-intubated patients see Appendix B) b) mechanical ventilation c) Patient is receiving inotrope or vasopressor

Exclusion Criteria:

1. Age less than 18 years

Patients with severe adult H1N1 pneumonia undergoing antiviral and oxygen therapy, mechanical ventilation and support with pulmonary rescue therapies ( nitric oxide, ECMO, HFO) in critically ill patients in Winnipeg. Patients with other similar disorders (viral pneumonia, bacterial pneumonia, septic shock, ARDS)that may require some of the same treatments.