Table 2. Injury characteristics, associated thoracic and non-thoracic injuries, and systemic analgesic use in patients receiving regional anaesthesia with systemic analgesia compared with those receiving systemic analgesia alone.

NSAIDs: Non-steroidal anti-inflammatory drugs; PCA: Patient-controlled analgesia; RA: Regional anaesthesia.

Note: Values are presented as n (%) or median (IQR), as appropriate. p-values represent between-group comparisons.

Characteristic	Total (N=682)	RA and systemic analgesia (n=126)	Systemic analgesia only (n=556)	p-value	Statistical test, statistic, and effect size
Rib fractures
Number, median (IQR)	3 (2-4)*	4 (3-6)	3 (3-4)	<0.001	Mann-Whitney U test
Laterality, n (%)
Unilateral	595 (87)	114 (90)	481 (87)	0.228	Pearson’s χ² test (overall); χ²(1)=1.451; Cramér’s V=0.046
Bilateral	87 (13)	12 (10)	75 (13)
Other thoracic injuries, n (%)
Lung contusion	103 (15)	33 (26)	70 (13)	<0.001	Pearson’s χ² test; χ²(1)=14.819; Cramér’s V=0.147
Pneumothorax	153 (22)	54 (43)	99 (18)	<0.001	Pearson’s χ² test; χ²(1)=37.046; Cramér’s V=0.233
Flail segment	30 (4)	14 (11)	16 (3)	<0.001	Pearson’s χ² test; χ²(1)=16.559; Cramér’s V=0.156
Haemothorax	88 (13)	27 (21)	61 (11)	0.002	Pearson’s χ² test; χ²(1)=9.996; Cramér’s V=0.121
Subcutaneous emphysema	75 (11)	31 (25)	44 (8)	<0.001	Pearson’s χ² test; χ²(1)=29.233; Cramér’s V=0.207
Injuries other than thoracic injuries, n (%)	283 (42)	55 (44)	228 (41)	0.587	Pearson’s χ² test; χ²(1)=0.296; Cramér’s V=0.021
Analgesia, n (%)
Paracetamol	634 (93)	121 (96)	513 (92)	0.136	Pearson’s χ² test; χ²(1)=2.226; Cramér’s V=0.057
NSAIDs	202 (30)	47 (37)	155 (28)	0.036	Pearson’s χ² test; χ²(1)=4.376; Cramér’s V=0.080
Opioids	593 (87)	121 (96)	472 (85)	<0.001	Pearson’s χ² test; χ²(1)=11.234; Cramér’s V=0.128
PCA	358 (52)	104 (83)	254 (46)	<0.001	Pearson’s χ² test; χ²(1)=55.953; Cramér’s V=0.286