Table 3 Respiratory outcomes at 2 years.

Outcome	HFOV		CV
	No/total	%	No/total	%	Relative risk*	95% CI†
Chest symptoms
Coughing	84/172	49	98/194	51	0.97	0.79 to 1.19
>Once a week	21/81	26	33/97	34	0.76	0.48 to 1.21
Once a week, >once a month	17/81	21	15/97	15	–	–
Once a month or less	43/81	53	49/97	51	­–	–
With exercise	15/61	25	28/76	37	0.67	0.39 to 1.13
With infection	68/81	84	88/98	90	0.93	0.83 to 1.05
Wheezing	56/167	34	75/187	40	0.84	0.63 to 1.10
>Once a week	16/53	30	21/72	29	1.04	0.60 to 1.79
Once a week, >once a month	6/53	11	12/72	17	–	–
Once a month or less	31/53	58	39/72	54	–	–
With exercise	13/42	31	26/60	43	0.71	0.42 to 1.22
With infection	50/56	89	66/73	90	0.99	0.88 to 1.11
Chest medicines
Last 12 months	94/171	55	115/192	60	0.92	0.77 to 1.10
Bronchodilators	63/171	37	82/192	43	0.86	0.67 to 1.11
Inhaled steroids	36/171	21	50/192	26	0.81	0.56 to 1.18
Any inhaled drug	63/171	37	85/192	44	0.83	0.65 to 1.07
Other
On home oxygen now	2/173	1	4/194	2	0.56	0.10 to 3.02

*Relative risk is the ratio of the risk of the most severe adverse outcome in the two groups, HFOV/CV.

†95% confidence intervals of relative risk.

HFOV, High frequency oscillatory ventilation; CV, conventional ventilation.