Fig. 1

Schematic view of the temporary negative pressure isolation intensive care unit. We divided the space to include a common anteroom, a common negative pressure isolation zone to accommodate three beds, two preexisting airborne infection isolation rooms (AIIRs), and a nursing station. Atmospheric air was supplied to the ICU including AIIRs via a mechanism that maintained constant air volume through common inlet duct systems. The air returned from ICU through common outlet duct systems; the AIIRs utilized independent exhaust systems that were controlled by a variable air volume system to maintain a set negative pressure. To generate negative pressure in the anteroom, we added temporary duct systems that were connected to preexisting independent exhaust systems. An air volume control damper was used to maintain a negative pressure gradient between preexisting AIIRs and the anteroom (− 5.0 Pa) at a level below the standard negative pressure (− 2.5 Pa) recommended for these facilities. The common negative pressure isolation zone was equipped with five mobile negative-air machines that generated negative pressure (− 5.0 Pa) compared to the anteroom. Airflow in isolation rooms reached 15–20 air exchanges per hour. The negative pressure in the ICU was tightly monitored and maintained. Patients were monitored via an observation window, closed-circuit television, and central monitoring systems. The entire renovation was completed within 5 days