Table.
Data summary from 7 evaluated trials of 2-patient and single-patient isolation zones created using portable HEPA filtration equipment and common hardware supplies.
| Trial No. | Supply/Exhaust (Open or Sealed) | Source Contained Within Inner Zone? | Source MigrationBetween Patients? | Worker or Patient Exposure Ratio (95% CI)∗ | Comments |
|---|---|---|---|---|---|
| 2-patient configuration | |||||
| 1 | Sealed/sealed | N | Y | 0.59 (0.45–0.76) | Curtain entrance closed, leak found under HEPA unit, no HEPA inlet partition |
| 2 | Sealed/sealed | Y | Y | 0.67 (0.44–1.06) | Curtain entrance gap maintained at 10 in (25 cm), no HEPA inlet partition |
| 3 | Sealed/sealed | Y | N | 0.13 (0.10–0.18) | Curtain entrance gap maintained at 10 in (25 cm), HEPA inlet partition added |
| Single-patient configuration | |||||
| 4 | Sealed/sealed | Y | NA | 0.29 (0.19–0.46) | Increased airflow: curtain entrance gap increased to 12 in (30 cm) |
| 5 | Open/open | Y | NA | 0.55 (0.37–0.86) | HVAC supply reduces incoming air, curtain entrance gap maintained at 10 in (25 cm) |
| 6 | Sealed/open | Y | NA | 0.37 (0.28–0.48) | Room HVAC supply located outside of isolation zone was open |
| 7 | Open/open | Y | NA | 0.70 (0.55–0.92) | Curtain gap maintained at 10 in |
Y, Yes; N, no; CI, confidence interval; NA, not applicable.
∗
This ratio is the mean particle count (within range of 1 to 2 μm) observed at the health care worker position divided by that observed near the source patient. It represents the relative ability of a tested scenario to reduce the risk of airborne exposure to the health care worker.