Predictive value of preoperative shock index for postoperative outcomes in traumatic splenic rupture patients undergoing splenectomy

Table 1 Comparison of basic characteristics among three groups, mean ± SD/n (%)/median (interquartile range)

Indicator	Low SI group (SI < 0.9, n = 78)	Moderate SI group (0.9 ≤ SI < 1.3, n = 89)	High SI group (SI ≥ 1.3, n = 45)	Statistic	P value	Effect size
Demographic characteristics
Age (years)	42.3 ± 15.7	45.2 ± 16.9	38.6 ± 14.2	F = 2.847	0.061	η2 = 0.027
Gender (male)	56 (71.8)	67 (75.3)	38 (84.4)	χ2 = 2.831	0.243	Cramer’s V = 0.116
BMI (kg/m2)	23.4 ± 3.2	24.1 ± 3.8	22.9 ± 3.5	F = 1.842	0.161	η2 = 0.017
BMI categories				χ2 = 5.1671	0.523	Cramer’s V = 0.111
Normal (18.5-23.9)	45 (57.7)	47 (52.8)	28 (62.2)
Overweight (24.0-27.9)	28 (35.9)	35 (39.3)	14 (31.1)
Obese (≥ 28.0)	5 (6.4)	7 (7.9)	3 (6.7)
Mechanism of injury				χ2 = 12.436	0.134	Cramer’s V = 0.171
Traffic accident	42 (53.8)	53 (59.6)	31 (68.9)
Fall from height	21 (26.9)	19 (21.3)	8 (17.8)
Heavy object impact	9 (11.5)	12 (13.5)	4 (8.9)
Sports injury	4 (5.1)	3 (3.4)	1 (2.2)
Violent injury	2 (2.6)	2 (2.2)	1 (2.2)
Time-related factors
Time from injury to admission (hours)	2.1 (1.0-4.2)	2.5 (1.2-4.8)	2.8 (1.5-5.1)	H = 3.742	0.154	ε2 = 0.018
Time from admission to surgery (hours)	4.2 (2.1-7.8)	2.8 (1.5-5.2)	1.8 (1.0-3.4)	H = 18.923	< 0.001	ε2 = 0.089
Past medical history
Hypertension	18 (23.1)	24 (27.0)	8 (17.8)	χ2 = 1.542	0.463	Cramer’s V = 0.086
Diabetes	7 (9.0)	11 (12.4)	3 (6.7)	χ2 = 1.234	0.540	Cramer’s V = 0.076
Coronary heart disease	5 (6.4)	8 (9.0)	2 (4.4)	χ2 = 1.076	0.584	Cramer’s V = 0.071
Medication history
Anticoagulant use	4 (5.1)	6 (6.7)	2 (4.4)	χ2 = 0.337	0.845	Cramer’s V = 0.040
Antiplatelet drug use	8 (10.3)	12 (13.5)	3 (6.7)	χ2 = 1.543	0.462	Cramer’s V = 0.086
Lifestyle
Smoking history	32 (41.0)	38 (42.7)	21 (46.7)	χ2 = 0.432	0.806	Cramer’s V = 0.045
Alcohol consumption history	28 (35.9)	34 (38.2)	19 (42.2)	χ2 = 0.523	0.770	Cramer’s V = 0.050

¹Linear trend χ² test.

BMI: Body mass index; SI: Shock index.

Table 2 Comparison of clinical indicators at admission among three groups, mean ± SD/n (%)

Indicator	Low SI group (n = 78)	Moderate SI group (n = 89)	High SI group (n = 45)	Statistic	P value	Effect size	Pairwise comparison P values3
Vital signs
Systolic BP (mmHg)	128.4 ± 15.2	106.3 ± 12.8	87.2 ± 11.6	F = 156.8	< 0.001	η2 = 0.600	P < 0.0014, P < 0.0015, P < 0.0016
Diastolic BP (mmHg)	78.6 ± 11.4	68.2 ± 10.7	56.3 ± 9.8	F = 67.4	< 0.001	η2 = 0.392	P < 0.0014, P < 0.0015, P < 0.0016
Mean arterial pressure (mmHg)	95.2 ± 11.8	80.9 ± 10.4	66.6 ± 9.2	F = 108.7	< 0.001	η2 = 0.510	P < 0.0014, P < 0.0015, P < 0.0016
Heart rate (beats/minutes)	92.3 ± 12.6	118.7 ± 14.2	142.8 ± 18.5	F = 189.3	< 0.001	η2 = 0.644	P < 0.0014, P < 0.0015, P < 0.0016
Respiratory rate (breaths/minutes)	18.2 ± 2.8	21.4 ± 3.6	26.8 ± 4.2	F = 92.6	< 0.001	η2 = 0.470	P < 0.0014, P < 0.0015, P < 0.0016
Body temperature (°C)	36.8 ± 0.6	36.6 ± 0.7	36.4 ± 0.8	F = 4.123	0.017	η2 = 0.0382	P = 0.1354, P = 0.0165, P = 0.2856
Shock index	0.72 ± 0.11	1.12 ± 0.11	1.65 ± 0.28	F = 892.4	< 0.001	η2 = 0.895	P < 0.0014, P < 0.0015, P < 0.0016
GCS score
Eye opening (E)	3.8 ± 0.5	3.6 ± 0.7	3.2 ± 0.9	F = 12.8	< 0.001	η2 = 0.109	P = 0.0244, P < 0.0015, P = 0.0186
Verbal response (V)	4.6 ± 0.8	4.2 ± 1.1	3.7 ± 1.3	F = 11.2	< 0.001	η2 = 0.097	P = 0.0154, P < 0.0015, P = 0.0456
Motor response (M)	5.8 ± 0.6	5.5 ± 0.9	5.1 ± 1.2	F = 8.9	< 0.001	η2 = 0.078	P = 0.0424, P < 0.0015, P = 0.0786
GCS total score	14.2 ± 1.4	13.3 ± 2.1	12.0 ± 2.6	F = 18.7	< 0.001	η2 = 0.152	P = 0.0064, P < 0.0015, P = 0.0036
GCS grading				χ2 = 14.281	0.001	Cramer’s V = 0.184
Mild (13-15 points)	72 (92.3)	73 (82.0)	30 (66.7)
Moderate (9-12 points)	6 (7.7)	15 (16.9)	13 (28.9)
Severe (≤ 8 points)	0 (0.0)	1 (1.1)	2 (4.4)
Splenic Injury grading				χ2 = 25.671	< 0.001	Cramer’s V = 0.246
Grade I	18 (23.1)	8 (9.0)	2 (4.4)
Grade II	32 (41.0)	25 (28.1)	6 (13.3)
Grade III	22 (28.2)	38 (42.7)	18 (40.0)
Grade IV	5 (6.4)	15 (16.9)	15 (33.3)
Grade V	1 (1.3)	3 (3.4)	4 (8.9)

¹Linear trend χ² test.

²Small effect size, limited clinical significance.

³Pairwise comparisons using Tukey honestly significant difference test, corrected α = 0.0167.

⁴Low shock index group vs moderate shock index group.

⁵Low shock index group vs high shock index group.

⁶Moderate shock index group vs high shock index group.

BP: Blood pressure; GCS: Glasgow Coma Scale; SI: Shock index.

Table 3 Comparison of laboratory test indicators among three groups, mean ± SD

Indicator	Low SI group (n = 78)	Moderate SI group (n = 89)	High SI group (n = 45)	Statistic	P value	Effect size	Pairwise comparison P values2
Blood routine indicators
Hemoglobin (g/L)	118.3 ± 18.7	96.7 ± 16.4	78.2 ± 15.8	F = 89.6	< 0.001	η2 = 0.461	P < 0.0013, P < 0.0014, P < 0.0015
Red blood cell count (× 1012/L)	3.94 ± 0.62	3.23 ± 0.55	2.61 ± 0.53	F = 87.3	< 0.001	η2 = 0.455	P < 0.0013, P < 0.0014, P < 0.0015
Hematocrit (%)	35.4 ± 5.6	28.9 ± 4.9	23.4 ± 4.7	F = 88.9	< 0.001	η2 = 0.459	P < 0.0013, P < 0.0014, P < 0.0015
White blood cell count (× 109/L)	9.8 ± 3.2	12.4 ± 4.1	15.6 ± 5.3	F = 32.4	< 0.001	η2 = 0.237	P < 0.0013, P < 0.0014, P = 0.0015
Platelet count (× 109/L)	245.6 ± 68.4	198.3 ± 58.7	128.4 ± 46.2	F = 42.8	< 0.001	η2 = 0.291	P < 0.0013, P < 0.0014, P < 0.0015
Coagulation function indicators
PT (seconds)	12.8 ± 1.6	14.2 ± 2.1	16.8 ± 2.9	F = 48.9	< 0.001	η2 = 0.319	P < 0.0013, P < 0.0014, P < 0.0015
APTT (seconds)	32.4 ± 4.8	36.7 ± 5.9	42.3 ± 7.2	F = 42.1	< 0.001	η2 = 0.287	P < 0.0013, P < 0.0014, P < 0.0015
INR	1.08 ± 0.14	1.19 ± 0.18	1.41 ± 0.24	F = 45.6	< 0.001	η2 = 0.303	P < 0.0013, P < 0.0014, P < 0.0015
Fibrinogen (g/L)	3.2 ± 0.8	2.8 ± 0.7	2.1 ± 0.6	F = 32.8	< 0.001	η2 = 0.239	P = 0.0033, P < 0.0014, P < 0.0015
Biochemical indicators
Serum creatinine (μmol/L)	78.4 ± 15.2	89.7 ± 18.6	112.3 ± 24.8	F = 48.7	< 0.001	η2 = 0.318	P < 0.0013, P < 0.0014, P < 0.0015
Blood urea nitrogen (mmol/L)	5.8 ± 1.4	7.2 ± 1.8	9.6 ± 2.4	F = 58.9	< 0.001	η2 = 0.360	P < 0.0013, P < 0.0014, P < 0.0015
Total bilirubin (μmol/L)	18.6 ± 5.2	22.4 ± 6.8	28.7 ± 8.9	F = 32.1	< 0.001	η2 = 0.235	P = 0.0023, P < 0.0014, P < 0.0015
ALT (U/L)	42.3 ± 12.8	58.7 ± 18.4	78.9 ± 24.6	F = 56.2	< 0.001	η2 = 0.349	P < 0.0013, P < 0.0014, P < 0.0015
AST (U/L)	38.9 ± 11.6	67.2 ± 20.8	95.6 ± 28.4	F = 102.8	< 0.001	η2 = 0.496	P < 0.0013, P < 0.0014, P < 0.0015
LDH (U/L)	245.8 ± 58.7	324.6 ± 72.9	428.7 ± 89.3	F = 98.4	< 0.001	η2 = 0.485	P < 0.0013, P < 0.0014, P < 0.0015
Electrolyte levels
Serum sodium (mmol/L)	139.2 ± 3.4	138.6 ± 3.8	137.1 ± 4.2	F = 4.89	0.008	η2 = 0.0451	P = 0.4383, P = 0.0064, P = 0.0635
Serum potassium (mmol/L)	4.1 ± 0.5	4.3 ± 0.6	4.6 ± 0.7	F = 10.8	< 0.001	η2 = 0.0941	P = 0.0453, P < 0.0014, P = 0.0215
Serum chloride (mmol/L)	103.8 ± 3.2	102.9 ± 3.6	101.4 ± 4.1	F = 6.47	0.002	η2= 0.0581	P = 0.1953, P = 0.0024, P = 0.0515
Blood gas analysis
pH value	7.38 ± 0.05	7.34 ± 0.06	7.28 ± 0.08	F = 39.8	< 0.001	η2 = 0.275	P < 0.0013, P < 0.0014, P < 0.0015
PaO2 (mmHg)	88.7 ± 12.4	82.3 ± 14.7	75.1 ± 16.8	F = 15.9	< 0.001	η2 = 0.132	P = 0.0063, P < 0.0014, P = 0.0215
PaCO2 (mmHg)	38.2 ± 4.6	35.8 ± 5.2	32.4 ± 6.1	F = 18.7	< 0.001	η2 = 0.152	P = 0.0093, P < 0.0014, P = 0.0035
Base excess BE (mmol/L)	-1.2 ± 2.4	-4.8 ± 3.1	-8.6 ± 3.8	F = 89.3	< 0.001	η2 = 0.460	P < 0.0013, P < 0.0014, P < 0.0015
Lactate level (mmol/L)	2.8 ± 0.9	4.6 ± 1.3	6.8 ± 1.9	F = 126.4	< 0.001	η2 = 0.547	P < 0.0013, P < 0.0014, P < 0.0015

¹Small effect size, limited clinical significance.

²Pairwise comparisons using Tukey honestly significant difference test, corrected α = 0.0167.

³Low shock index group vs moderate shock index group.

⁴Low shock index group vs high shock index group.

⁵Moderate shock index group vs high shock index group.

PT: Prothrombin time; APTT: Activated partial thromboplastin time; INR: International normalized ratio; ALT: Alanine aminotransferase; AST: Aspartate aminotransferase; LDH: Lactate dehydrogenase; PaO₂: Arterial oxygen partial pressure; PaCO₂: Arterial carbon dioxide partial pressure; BE: Base excess; SI: Shock index.

Table 4 Comparison of imaging examination results among three groups, n (%)

Indicator	Low SI group (n = 78)	Moderate SI group (n = 89)	High SI group (n = 45)	Statistic	P value	Corrected P value	Effect size	Pairwise comparison P values2
Splenic rupture extent				χ2 = 28.341	< 0.001	< 0.001	Cramer’s V = 0.258	P = 0.0063, P < 0.0014, P = 0.0245
Localized rupture	45 (57.7)	28 (31.5)	7 (15.6)
Extensive rupture	28 (35.9)	46 (51.7)	25 (55.6)
Shattered rupture	5 (6.4)	15 (16.9)	13 (28.9)
Hematoma size				χ2 = 26.881	< 0.001	< 0.001	Cramer’s V = 0.252	P = 0.0033, P < 0.0014, P = 0.0185
Small hematoma (< 5 cm)	52 (66.7)	35 (39.3)	9 (20.0)
Medium hematoma (5-10 cm)	21 (26.9)	38 (42.7)	21 (46.7)
Large hematoma (> 10 cm)	5 (6.4)	16 (18.0)	15 (33.3)
Intraperitoneal hemorrhage volume				χ2 = 42.671	< 0.001	< 0.001	Cramer’s V = 0.317	P < 0.0013, P < 0.0014, P = 0.0095
Small amount	52 (66.7)	29 (32.6)	5 (11.1)
Moderate amount	22 (28.2)	41 (46.1)	18 (40.0)
Large amount	4 (5.1)	19 (21.3)	22 (48.9)
Combined other organ injuries	25 (32.1)	42 (47.2)	28 (62.2)	χ2 = 9.871	0.007	0.042	Cramer’s V = 0.216	P = 0.0423, P = 0.0034, P = 0.1325
Liver injury	8 (10.3)	18 (20.2)	12 (26.7)	χ2 = 5.891	0.053	0.318	Cramer’s V = 0.167	P = 0.0783, P = 0.0214, P = 0.4235
Kidney injury	6 (7.7)	12 (13.5)	8 (17.8)	χ2 = 2.851	0.240	1.000	Cramer’s V = 0.116	P = 0.2343, P = 0.0784, P = 0.5195
Pancreatic injury	3 (3.8)	7 (7.9)	5 (11.1)	χ2 = 2.131	0.345	1.000	Cramer’s V = 0.100	P = 0.3123, P = 0.1294, P = 0.5375
Intestinal injury	5 (6.4)	8 (9.0)	6 (13.3)	χ2 = 1.461	0.482	1.000	Cramer’s V = 0.083	P = 0.5673, P = 0.2134, P = 0.4685
Pelvic fracture	8 (10.3)	15 (16.9)	11 (24.4)	χ2 = 3.841	0.147	0.882	Cramer’s V = 0.135	P = 0.2343, P = 0.0424, P = 0.3245

¹Linear trend χ² test.

²Pairwise comparisons using Bonferroni-corrected paired χ² test, corrected α = 0.0167.

³Low shock index group vs moderate shock index group.

⁴Low shock index group vs high shock index group.

⁵Moderate shock index group vs high shock index group.

SI: Shock index.

Table 5 Comparison of surgery-related indicators among three groups, n (%)/mean ± SD/median (interquartile range)

Indicator	Low SI group (n = 78)	Moderate SI group (n = 89)	High SI group (n = 45)	Statistic	P value	Effect size	Pairwise comparison P values2
Surgical timing				χ2 = 25.671	< 0.001	Cramer’s V = 0.348	P = 0.0093, P < 0.0014, P = 0.0035
Emergency surgery (< 4 hours)	28 (35.9)	52 (58.4)	38 (84.4)
Delayed surgery (≥ 4 hours)	50 (64.1)	37 (41.6)	7 (15.6)
Surgical approach				χ2 = 9.847	0.007	Cramer’s V = 0.216	P = 0.0423, P = 0.0034, P = 0.1325
Open splenectomy	58 (74.4)	78 (87.6)	43 (95.6)
Laparoscopic splenectomy	20 (25.6)	11 (12.4)	2 (4.4)
Operative time (minutes)	128.4 ± 32.6	156.7 ± 41.2	167.8 ± 35.4	F = 23.1	< 0.001	η2 = 0.181	P < 0.0013, P < 0.0014, P = 0.1325
Intraoperative blood loss (mL)	485.3 ± 124.7	732.6 ± 186.4	1126.8 ± 268.9	F = 152.3	< 0.001	η2 = 0.593	P < 0.0013, P < 0.0014, P < 0.0015
Intraoperative transfusion volume
Red blood cells (U)	2.3 ± 1.8	4.6 ± 2.4	7.8 ± 3.2	F = 78.9	< 0.001	η2 = 0.430	P < 0.0013, P < 0.0014, P < 0.0015
Plasma (mL)	186.4 ± 142.3	324.7 ± 198.6	542.8 ± 256.4	F = 48.6	< 0.001	η2 = 0.317	P < 0.0013, P < 0.0014, P < 0.0015
Platelets (U)	0.2 (0-1.0)	0.5 (0-1.5)	1.0 (0-3.0)	H = 18.4	< 0.001	ε2 = 0.087	P = 0.0423, P < 0.0014, P = 0.0155
Intraoperative blood pressure maintenance				χ2 = 37.891	< 0.001	Cramer’s V = 0.423	P < 0.0013, P < 0.0014, P = 0.0065
Stable (SBP ≥ 90 mmHg)	68 (87.2)	52 (58.4)	12 (26.7)
Unstable (SBP < 90 mmHg)	10 (12.8)	37 (41.6)	33 (73.3)
Vasoactive drug use	12 (15.4)	34 (38.2)	32 (71.1)	χ2 = 29.581	< 0.001	Cramer’s V = 0.373	P = 0.0033, P < 0.0014, P < 0.0015

¹Linear trend χ² test.

²Pairwise comparisons corrected α = 0.0167, continuous variables using Türkiye honestly significant difference test, categorical variables using Bonferroni-corrected paired χ² test, non-parametric variables using Dunn-Bonferroni test.

³Low shock index group vs moderate shock index group.

⁴Low shock index group vs high shock index group.

⁵Moderate shock index group vs high shock index group.

SBP: Systolic blood pressure; SI: Shock index.

Table 6 Comparison of main prognostic indicators among three groups, n (%)/median (interquartile range)

Indicator	Low SI group (n = 78)	Moderate SI group (n = 89)	High SI group (n = 45)	Statistic	P value	Effect size	Pairwise comparison P values2
Postoperative complications (Clavien-Dindo grading)				χ2 = 31.781	< 0.001	Cramer’s V = 0.274	P = 0.0033, P < 0.0014, P = 0.0245
No complications	48 (61.5)	32 (36.0)	8 (17.8)
Grade I	18 (23.1)	25 (28.1)	12 (26.7)
Grade II	9 (11.5)	21 (23.6)	13 (28.9)
Grade III	3 (3.8)	8 (9.0)	7 (15.6)
Grade IV	0 (0.0)	3 (3.4)	3 (6.7)
Grade V	0 (0.0)	0 (0.0)	2 (4.4)
Severe complications (≥ grade III)	3 (3.8)	11 (12.4)	12 (26.7)	χ2 = 12.581	0.002	Cramer’s V = 0.244	P = 0.0633, P < 0.0014, P = 0.0425
30-day postoperative mortality	0 (0.0)	0 (0.0)	2 (4.4)	Fisher’s exact test	0.039
ICU admission rate	15 (19.2)	42 (47.2)	34 (75.6)	χ2 = 32.171	< 0.001	Cramer’s V = 0.390	P < 0.0013, P < 0.0014, P = 0.0035
Mechanical ventilation time (hours)	8.5 (4.2-18.6)	22.4 (12.8-38.7)	48.2 (28.6-72.4)	H = 56.8	< 0.001	ε2 = 0.268	P < 0.0013, P < 0.0014, P < 0.0015
Hospital stays (days)	12.5 (8.2-18.4)	16.8 (11.2-24.6)	23.7 (15.8-35.2)	H = 32.4	< 0.001	ε2 = 0.153	P = 0.0093, P < 0.0014, P = 0.0185

¹Linear trend χ² test.

²Pairwise comparisons corrected α = 0.0167, categorical variables using Bonferroni-corrected paired χ² test, non-parametric variables using Dunn-Bonferroni test.

³Low shock index group vs moderate shock index group.

⁴Low shock index group vs high shock index group.

⁵Moderate shock index group vs high shock index group.

ICU: Intensive care unit; SI: Shock index.

Table 7 Comparison of secondary prognostic indicators among three groups, mean ± SD/n (%)

Indicator	Low SI group (n = 78)	Moderate SI group (n = 89)	High SI group (n = 45)	Statistic	P value	Effect size	Pairwise comparison P values2
Postoperative hemoglobin changes (g/L)
24 hours postoperative	106.8 ± 16.4	84.2 ± 14.7	68.9 ± 13.2	F = 89.6	< 0.001	η2 = 0.461	P < 0.0013, P < 0.0014, P < 0.0015
48 hours postoperative	109.2 ± 15.8	89.6 ± 15.1	74.3 ± 14.6	F = 78.4	< 0.001	η2 = 0.428	P < 0.0013, P < 0.0014, P < 0.0015
72 hours postoperative	112.4 ± 16.2	95.7 ± 16.8	81.2 ± 15.9	F = 64.7	< 0.001	η2 = 0.382	P < 0.0013, P < 0.0014, P < 0.0015
Reoperation rate	2 (2.6)	8 (9.0)	9 (20.0)	χ2 = 8.741	0.013	Cramer’s V = 0.203	P = 0.0963, P = 0.0034, P = 0.0845
Reoperation causes				Fisher’s exact test	0.024
Postoperative hemorrhage	1 (1.3)	5 (5.6)	6 (13.3)
Abdominal infection	1 (1.3)	2 (2.2)	2 (4.4)
Pancreatic fistula management	0 (0.0)	1 (1.1)	1 (2.2)
mRS score (at discharge)				χ2 = 28.461	< 0.001	Cramer’s V = 0.259	P = 0.0063, P < 0.0014, P = 0.0215
0 points (completely asymptomatic)	52 (66.7)	38 (42.7)	12 (26.7)
1 point (no significant functional deficit)	18 (23.1)	28 (31.5)	14 (31.1)
2 points (mild functional deficit)	6 (7.7)	15 (16.9)	11 (24.4)
3 points (moderate functional deficit)	2 (2.6)	6 (6.7)	5 (11.1)
4 points (moderate to severe functional deficit)	0 (0.0)	2 (2.2)	1 (2.2)
5 points (severe functional deficit)	0 (0.0)	0 (0.0)	0 (0.0)

¹Linear trend χ² test.

²Pairwise comparisons corrected α = 0.0167 continuous variables using Türkiye honestly significant difference test, categorical variables using Bonferroni-corrected paired χ² test.

³Low shock index group vs moderate shock index group.

⁴Low shock index group vs high shock index group.

⁵Moderate shock index group vs high shock index group.

mRS: Modified Rankin Scale; SI: Shock index.

Table 8 Multivariate logistic regression analysis of factors affecting severe postoperative complications

Variable	Univariate analysis		Multivariate analysis
	OR (95%CI)	P value	OR (95%CI)	P value
Shock index (continuous variable)	3.68 (2.15-6.28)	< 0.001	2.34 (1.25-4.38)	0.008

OR: Odds ratio; CI: Confidence interval.