Comparison 1. Double wall versus single wall Incubator.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Oxygen consumption	3	66	Oxygen consumption (Fixed, 95% CI)	‐0.59 [‐1.09, ‐0.09]
2 Heat production and heat loss	2		Heat production (Fixed, 95% CI)	Subtotals only
2.1 Heat production	2	46	Heat production (Fixed, 95% CI)	‐0.27 [‐0.37, ‐0.17]
2.2 Heat loss	2	46	Heat production (Fixed, 95% CI)	‐0.17 [‐0.41, 0.06]
2.3 Heat storage	2	46	Heat production (Fixed, 95% CI)	0.11 [0.06, 0.16]
3 Heat exchange data	2		Heat exchange (Fixed, 95% CI)	Subtotals only
3.1 Evaporative heat loss	2		Heat exchange (Fixed, 95% CI)	0.93 [0.81, 1.06]
3.2 Radiant heat loss	1		Heat exchange (Fixed, 95% CI)	0.86 [0.76, 0.98]
3.3 Convective heat loss	1		Heat exchange (Fixed, 95% CI)	1.38 [1.03, 1.84]
4 Incubator temperatures	3		Incubator measures (Fixed, 95% CI)	Subtotals only
4.1 Incubator air	3		Incubator measures (Fixed, 95% CI)	‐0.21 [‐0.48, 0.06]
4.2 Incubator ‐ inner wall	3		Incubator measures (Fixed, 95% CI)	1.48 [1.09, 1.88]
4.3 Incubator wall ‐ outer wall	2		Incubator measures (Fixed, 95% CI)	0.78 [0.57, 0.99]
5 Infant temperatures	3		Infant temperatures (Fixed, 95% CI)	Subtotals only
5.1 Abdominal wall temperature	3	66	Infant temperatures (Fixed, 95% CI)	0.15 [0.08, 0.22]
5.2 Rectal temperature	2	46	Infant temperatures (Fixed, 95% CI)	0.05 [‐0.03, 0.13]
6 Physiologic parameters	2		Physiologic (Fixed, 95% CI)	Subtotals only
6.1 Heart Rate	2	50	Physiologic (Fixed, 95% CI)	‐1.71 [‐4.26, 0.84]
6.2 Respiratory rate	2	50	Physiologic (Fixed, 95% CI)	0.44 [‐2.35, 3.24]
7 Operative conditions	3		Operative conditions (Fixed, 95% CI)	Subtotals only
7.1 Operative temperature	2		Operative conditions (Fixed, 95% CI)	0.51 [0.22, 0.81]
7.2 Incubator air humidity	2		Operative conditions (Fixed, 95% CI)	0.46 [‐0.43, 1.35]