Table 2

Cross-classified hierarchical models of factors significantly associated with proportion of time in target range, and proportion of time with saturation 98–100%

	Target range			98–100%
	Coefficient	SE	p Value	Coefficient	SE	p Value
Adjusted overall mean	0.163	0.032	<0.001	0.268	0.039	<0.001
Postmenstrual ages, per week	−0.020	0.002	<0.001	0.043	0.003	<0.001
Fraction of inspired oxygen >0.5 compared with <0.5	0.039	0.020	0.047	0.174	0.032	<0.001
Nurse:patient ratio^*	0.028	0.027	0.293	−0.030	0.016	0.057
High-frequency oscillator ventilation, nurse caring for one patient	0.128	0.034	<0.001	Reference group: all monitoring periods on high-frequency oscillator ventilation
Nurse caring for two or more patients	−0.082	0.036	0.021
Synchronised intermittent mandatory ventilation	−0.041	0.018	0.017	0.112	0.026	<0.001
Continuous positive airway pressure	0.018	0.012	0.112	0.005	0.025	0.829
Nasal cannula, nurse caring for two patients	Reference group: all monitoring periods on nasal cannula			−0.02	0.035	0.566
Nurse caring for three or more patients				0.062	0.024	0.011

↵* Nurse:patient ratio term defined differently for the two models. See text.