Table 5.

Significant interactions between differences in analgesic use during daytime and night-time and characteristics of children, centres and procedures in a multivariate, multilevel analysis*

Factor	Interaction test (p value)	Interaction direction		OR
		Increase difference†	Decrease difference†
Day of procedure‡	<0.001	D2–D14		1.56 (1.24–1.95)
Mechanical ventilation	<0.05	Absence of mechanical ventilation during procedure		1.20 (1.02–1.43)
Parental presence	<0.001		Parents present	0.58 (0.44–0.78)
Nurse shift	<0.01	12-hour nurse shifts		1.42 (1.05–5.55)
Written protocols for sucrose analgesia	<0.001	Absence of written protocols for sucrose analgesia		2.44 (1.56–3.70)

*This is a multilevel analysis. The exposure was time of procedure (daytime vs night-time). Factors in level 1 (associated with procedure) were day of procedure, mechanical ventilation, parental presence and continuous analgesia. Factors in level 2 (associated with children) were surgery, sex and gestational age. Factors in level 3 (associated with centre) were nurse shift, nurse rotation, pain coordinator, written protocols for sucrose analgesia, parental presence authorised 24 h, night head nurse and teaching status). Interactions between each factor and daytime versus night-time were included in the model. Only factors that significantly interacted with time of procedure are shown in the table.

†Refers to the difference in analgesic use during daytime compared with night-time.

‡Related to admission.