The COVID-19 pandemic has exposed the precarious demand-capacity balance in Canadian hospitals, including critical care where there is an urgent need for trained health care professionals to dramatically increase ICU capacity. The impact of the pandemic on ICUs varied significantly across the country with provinces that implemented public health measures later and relaxed them sooner being impacted more severely. Pediatric ICUs routinely admitted adult patients. Non-ICU areas were converted to ICUs and staff were redeployed from other essential service areas. Faced with a lack of critical care capacity, triage plans for ICU admission were developed and nearly implemented in some provinces. Twenty eight percent of patients in Canadian ICUs who required mechanical ventilation died. Surviving patients have required prolonged ICU admission, hospitalization and extensive ongoing rehabilitation. Family members of patients were not permitted to visit, resulting in additional psychological stresses to patients, families, and healthcare teams. ICU professionals also experienced extreme psychological stresses from caring for such large numbers of critically ill patients, often in sub-standard conditions. This resulted in large numbers of health workers leaving their professions. This pandemic is not yet over, and it is likely that new pandemics will follow. A review and recommendations for the future are provided.