The Christchurch earthquake: ultrasound in a mass trauma event

Brief background Christchurch Public Hospital (CPH) and Christchurch Women’s Hospital (CWH) occupy the same physical site but are distinctively different buildings. They are sited close to the Avon River and Hagley Park and about a 10 minute walk to the central business district. CWH opened in 2005 as a “state-of-the-art” tertiary level women’s hospital that accommodates a tertiary level neonatal intensive care unit. It is built on a foundation system offering the most sophisticated earthquake protection available. CWH has five levels, with the radiology department on the ground floor (one x-ray room, four ultrasound rooms, radiologist reporting stations, sonographers work room, fetal medicine scanning and consulting rooms). Christchurch Hospital consists of two major buildings, the Riverside block, completed in 1980, and the Parkside block, completed in 1991. It is the major tertiary level hospital in New Zealand’s South Island, covering a large geographical area. The Emergency Department (ED) is located on the ground floor and is one of the busiest in the southern hemisphere (+70,000 visits per year) and had just completed a much needed upgrade before the earthquakes. Two x-ray rooms and a trauma room are part of the ED radiology services. The main radiology department is on level one of the public hospital campus and is located between the Riverside and Parkside blocks. It has three CT scanners, two DSA rooms, one MRI unit, five ultrasound rooms (including vascular lab) and general x-ray rooms. Sonographers work between the Christchurch Public and Women’s departments on a rotational basis. Although shaken by the 7.3 magnitude earthquake of 4th September 2010, the hospital suffered only minor damage and fortunately there were no fatalities. The September earthquake had however shown us that there was a vulnerability to power supplied to radiology, including x-ray services in ED, which was being addressed at the time of the February 2011 earthquake. February 22nd, 12.51 hours Unlike many natural disasters such as floods and extreme weather events there are no warnings with earthquakes. This was the case on the 22nd February 2011. Most of the sonographers on duty that day were getting ready to leave the tea room at CWH to return to work at CPH and CWH. Two of the team had left the department and gone into town. At 12.51 hrs the earthquake struck. Parts of the tea room ceiling fell down, staff struggled to stand up, non-secured items flew across the room and windows imploded. In addition, the power went off, came back on and went off again at irregular intervals throughout the next few hours. The shaking went on for approximately 37 seconds however the aftershocks were ongoing; with the largest being 5.9 in magnitude at approximately 14.51 hrs. We were to learn later that the magnitude of the 1251 hr quake was 6.3 in magnitude, which sounded relatively low for those who experienced it. However it was centred only 5 km deep and 10 km from the city centre. It had acceleration forces of up to 2.2 G (among the highest ever recorded) with the greatest vertical accelerations on record. It had caused major devastation throughout the central city and surrounding areas (particularly in the central city and eastern suburbs). There was widespread loss of power and communications, extensive flooding and liquefaction,1 roads were in gridlock as people tried to move out of the city to safety and make contact with loved ones. Soon there was also a loss of water and sewage services. We had no real idea of what was happening outside the hospital, and many outside the hospital had no idea if the hospital itself was still standing or functional. The Christchurch earthquake: ultrasound in a mass trauma event