Disasters, emergencies, and the required response can be viewed in terms of stages, and the type of information collected must be appropriate for every stage of the emergency response.
Stage I (Day 1)
The first response in sudden-impact disasters comes from the affected community, and local priorities are to simultaneously assess and respond rapidly to the crisis. This implies that medical measures are usually implemented without complete information. Local resources are spontaneously and, often, effectively reassigned and adjusted before the first results of a rapid assessment are available.
During this period, when additional resources have not yet arrived, the highest health priority is the emergency medical response.
The first injury estimates are needed within the 24 hours following impact to guide requests for assistance. However, in many sudden-impact disasters, it is difficult to project numbers of casualties during this period. An important task of preparedness is to review the experience gained in past disasters (e.g. earthquakes and floods) and prepare guidelines for estimating casualties (for instance, in the case of earthquakes, based on recorded magnitude, population density, and construction type).
Stage II (Day 2)
By this time, most critical patients in accessible areas have already received initial medical attention and immediate life-saving measures become less important.
During this stage, a rapid assessment should determine:
- needs for emergency medical response in the less accessible areas;
- shortages in primary health care resources;
- secondary needs: health care, shelter, food and water for the population; and
- needs for additional national and international resources (to re-establish essential health services, and restock medical supplies and equipment).
Stage III (Days 3-5)
At this point, restoring primary health care, lifeline systems, and adequate shelter become priorities.
Therefore, a rapid assessment should focus progressively on needs for:
- environmental health, food security and safety, and public health services;
- special protection and shelter for vulnerable groups; and
- re-establishing the primary health care system, and restoring health facilities.
Stage IV (after Day 5)
After day 5, emergency plans should be fully implemented, and a response and recovery operation ideally in place, covering all sectors.
From this stage on, health assessment should:
- be based on an established surveillance system;
- incorporate information on both disease surveillance, and the health care system;
- focus on health trends as they relate to the response and recovery operation itself; and
- contribute to the most effective use of national and international resources.