Comparison 2. Clinical improvements.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Change in respiratory rate	2	91	Mean Difference (IV, Fixed, 95% CI)	‐3.81 [‐5.78, ‐1.84]
2 Change in arterial oxygen saturation	1	19	Mean Difference (IV, Fixed, 95% CI)	‐1.7 [‐3.76, 0.36]
3 Change in arterial partial pressure of carbon dioxide (pCO₂) and partial pressure of oxygen (pO₂)	2	50	Mean Difference (IV, Fixed, 95% CI)	‐2.62 [‐5.29, 0.05]
4 Duration of hospital stay (days)	2	50	Mean Difference (IV, Fixed, 95% CI)	0.07 [‐0.36, 0.50]