Comparison 9. Laminar air flow with HEPA filter versus without flow or filter.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
9.1 Reduction in the level of contamination in aerosols (CFU per cubic feet/minute/patient)	1		Mean Difference (IV, Random, 95% CI)	Totals not selected
9.1.1 At about 30 inches (1.5 metres) from the floor	1		Mean Difference (IV, Random, 95% CI)	Totals not selected
9.1.2 At about 8 to 12 inches (20 to 30 cm) from participant's mouth	1		Mean Difference (IV, Random, 95% CI)	Totals not selected