Gastrointestinal manifestations of critical ill heatstroke patients and their associations with outcomes: A multicentre, retrospective, observational study

Table 1 Clinical characteristics, laboratory findings at admission, gastrointestinal symptoms findings, complications, treatments, and clinical outcomes of the study patients, according to developed gastrointestinal symptoms or not¹

	All Patients, (n = 713)	GI Symptoms whether2		P value
		Yes (n = 132)	No (n = 581)
Characteristic
Age, median (IQR), yr	72.0 (64.0-80.0)	70.0 (59.0-76.0)	73.0 (64.0-81.0)	0.076
Distribution, n (%)
0-39 yr	13 (1.8)	1 (0.01)	12 (2.1)	—
40-59 yr	132 (18.5)	32 (24.2)	100 (17.2)	—
60-79 yr	371 (52.0)	73 (55.3)	298 (51.2)	—
≥ 80 yr	197 (27.6)	26 (19.6)	171 (29.4)	—
Female sex	332 (46.6)	60 (45.4)	272 (46.8)	0.561
BMI, median (IQR), kg/m2	22.1 (20.3-24.2)	22.5 (20.0-24.6)	22.0 (20.3-24.1)	0.875
GCS score at ICU admission, median (IQR)	6.0 (4.0-9.0)	5.0 (3.0-7.0)	6.0 (4.0-9.0)	0.018
NRS-2002 score at ICU admission, median (IQR)	4.0 (3.0-5.0)	3.0 (3.0-5.0)	4.0 (3.0-5.0)	0.014
Body temperature on admission
Patients, n (%)	710 (99.1)	132 (100.0)	578 (98.8)	0.374
Temperature, median (IQR), °C	40.7 (40.0-41.3)	41.0 (40.1-42.0)	40.5 (40.0-41.2)	< 0.001
Heat exposure duration, median (IQR), h	4.0 (2.0-6.0)	4.0 (2.0-6.0)	4.0 (2.0-6.3)	0.206
Distribution of body temperature on admission, n (%)
< 37.3 °C	6 (1.0)	0 (0.0)	6 (0.1)	—
37.3–38.0 °C	13 (2.1)	1 (0.8)	12 (2.3)	—
38.1–39.0 °C	59 (9.3)	8 (6.7)	51 (9.9)	—
39.1–40.0 °C	175 (27.7)	33 (27.7)	142 (27.7)	—
> 40.0 °C	379 (60.0)	77 (64.7)	302 (58.9)	—
Number of complaints and symptoms on admission, n (%)
< 2	169/672 (25.1)	27/126 (21.4)	142/546 (26.3)	0.053
2-3	348/672 (51.8)	47/126 (37.3)	301/546 (55.1)	0.094
> 3	155/672 (23.1)	52/126 (41.3)	103/546 (18.9)	< 0.001
Complaints and symptoms on admission, n (%)
Fever	476 (66.8)	93 (70.5)	383 (65.9	0.272
Altered mental state or behavior	343 (48.1)	55 (41.7)	288 (49.6	0.177
Dry skin or excessive sweating	65 (9.1)	20 (15.1)	45 (7.7)	< 0.001
Rubefaction	32 (4.5)	11 (8.3)	21 (3.6)	0.035
Fast pulse	142 (19.9)	40 (30.3)	102 (17.5	< 0.001
Polypnea	175 (24.5)	38 (38.7)	137 (23.6)	0.019
Headache	15 (2.1)	3 (2.3)	12 (2.1)	0.438
Syncope	309 (43.3)	85 (64.4)	224 (38.6)	< 0.001
Other	102 (14.3)	27 (20.5)	75 (12.9)	0.013
Coexisting disorder, n (%)
Diabetes	87 (12.2)	10 (7.6)	77 (13.3)	0.225
Hypertension	187 (26.2)	36 (27.3)	151 (26.0)	0.985
Chronic obstructive pulmonary disease	124 (17.4)	21 (15.9)	103 (17.7)	0.697
Chronic cardiac insufficiency	79 (11.1)	16 (12.1)	63 (10.8)	0.541
Hepatitis B infection	14 (2.0)	1 (0.8)	13 (2.2)	0.488
Cancer3	5 (0.7)	3 (2.3)	2 (0.3)	0.033
Chronic renal disease	17 (2.4)	2 (1.5)	15 (2.6)	0.149
Immunodeficiency	9 (1.3)	3 (2.3)	6 (1.0)	0.965
Laboratory findings, median (IQR)
PaO2/FiO2 ratio	239.0 (174.0-323.0)	238.0 (185.5-300.5)	248.0 (190.0-336.0)	0.064
White-cell count, 109/L	11.7 (8.2-15.5	10.0 (6.6-14.4),	11.7 (8.4-15.5)	0.032
Lymphocyte count, 109/L	1.3 (0.7-2.4)	0.9 (0.5-2.3)	1.0 (0.6-2.1)	0.746
Platelet count, 109/L	108.0 (73.0-162.0)	84.0 (45.0-115.0)	110.0 (75.0-165.5)	0.147
Hemoglobin, g/L	123 (109-138)	115 (102-127)	124 (109-138)	0.014
Albumin, g/L	37.0 (33.2-40.2)	33.4 (29.1-43.8)	37.0 (33.3-40.3)	0.014
Other findings, median (IQR)
C-reactive protein, mg/L	5.0 (1.0-11.8)	11.9 (5.1-32.1)	5.0 (1.0-12.0)	0.005
Procalcitonin, ng/mL	2.7 (0.5-13.1)	3.2 (0.4-8.9)	2.8 (0.5-12.6)	0.593
Lactate dehydrogenase, U/L	367.9 (284.8-547.5)	327.0 (273.0-507.4)	362.5 (281.8-524.0)	0.667
Aspartate aminotransferase, U/L	79.0 (40.9-191.0)	115.9 (51.3-269.8)	74.0 (39.3-168.8)	0.128
Alanine aminotransferase, U/L	38.0 (21.0-85.0)	48.0 (28.1-104.1)	36.0 (20.0-77.3)	0.479
Total bilirubin, μmol/L	17.9 (12.5-25.7)	18.2 (11.8-258.9),	17.9 (12.5-25.9)	0.186
CK-Mb, U/L	10.0 (2.8-32.0)	13.6 (4.2-74.6)	9.9 (2.7-31.7)	0.539
Creatinine, μmol/L	125.0 (89.8-169.2)	122.0 (84.0-162.	123.0 (88.4-169.2)	0.944
D-dimer, mg/L	4.6 (1.8-12.9)	4.1 (2.1-8.6)	4.7 (1.7-12.8)	0.561
Minerals, median (IQR), mmol/L
Sodium	133.3 (129.0-139.0)	136.0 (132.0-140.0)	133.6 (129.0-139.0)	0.158
Potassium	3.2 (2.9-3.8)	3.6 (3.0-3.9)	3.2 (2.9-3.8)	0.043
Lactate	3.5 (2.1-5.1)	3.1 (1.6-4.1)	3.4 (2.0-5.1)	0.036
GI symptoms findings, n (%)
Duration of GI symptoms, median (IQR), d	—	4.0 (2.0-7.0)	—	—
Diarrhea	—	99 (75.0)	—	—
Flatulence	—	36 (27.3)	—	—
Nausea/vomiting	—	21 (15.9)	—	—
Bloody stools	—	8 (6.1)	—	—
Complications, n (%)
Number of complications
< 2	263 (36.9)	28 (21.1)	235 (38.8)	0.002
2-3	133 (18.7)	12 (9.2)	121 (19.8)	0.025
> 3	317 (44.5)	92 (69.7)	225 (41.4)	< 0.001
Disturbance of water and electrolyte	412 (57.8)	95 (72.0)	317 (54.6)	0.013
Rhabdomyolysis	102 (14.3)	34 (25.8)	68 (11.7)	0.004
Myocardial damage	281 (39.4)	70 (53.0)	211 (36.3)	< 0.001
Disseminated intravascular coagulation	221 (31.0)	62 (46.9)	159 (27.4)	0.006
Acute respiratory distress syndrome	256 (35.9)	66 (50.0)	190 (32.7)	0.001
Acute kidney injury	299 (41.9)	83 (62.9)	216 (37.2)	0.003
Acute liver function impairment	305 (42.8)	81 (61.4)	224 (38.6)	< 0.001
Central nervous system damage	256 (35.9)	74 (56.1)	182 (31.9)	0.003
Treatments, n (%)
Mechanical ventilation
Invasive	439 (61.7)	108 (82.6)	331 (57.1)	< 0.001
Noninvasive	10 (1.4)	0 (0.0)	10 (1.6)	0.271
Use of continuous renal-replacement therapy	24 (3.4)	7 (9.2)	17 (2.7)	0.003
Length of ICU stay, median (IQR), d	2.0 (1.0-4.0)	4.0 (2.0-7.0)	2.0 (1.0-3.0)	0.001
Clinical outcomes at data cutoff, n (%)
Hospital discharge	349 (48.9)	64 (48.5)	285 (49.1)	0.906
Death	144 (20.2)	26 (19.7)	118 (20.3)	0.874
Still hospitalization	187 (26.2)	33 (25.0)	154 (26.5)	0.723
Transferred to another hospital	33 (4.6)	9 (6.8)	24 (4.1)	< 0.001

¹The denominators of patients who were included in the analysis are provided if they differed from the overall numbers in the group. Percentages may not total 100 because of rounding.

²Nausea/vomiting, diarrhea, flatulence, or bloody stools are defined as gastrointestinal symptoms.

³Included in this category is any type of cancer.

IQR: Interquartile range; GCS: Glasgow coma scale; NRS: Nutrition risk screening; GI: Gastrointestinal; BMI: Body mass index; ICU: Intensive care unit; CK-Mb: Creatine kinase.

Table 2 Clinical characteristics of the heatstroke patients with endotracheal intubation, according to developed gastrointestinal symptoms or not¹

	All intubated patients (n = 439)	GI symptoms whether2		P value
		Yes (n = 108)	No (n = 331)
Characteristic
Age, median (IQR), yr	71.0 (63.0-80.0)	72.0 (64.0-80.0)	69.5 (59.8-78.0)	0.202
Female sex, n (%)	197 (44.9)	49 (45.4)	148 (44.7)	0.905
GCS score at ICU admission, median (IQR)	4.0 (3.0-5.0)	4.0 (3.0-5.0)	4.0 (4.0-5.0)	0.204
NRS score at ICU admission, median (IQR)	4.0 (3.0-5.0)	3.0 (3.0-5.0)	4.0 (3.0-5.0)	0.057
Body temperature on admission
Patients, n (%)	439 (100.0)	108 (100.0)	331 (100.0)	0.348
Temperature, median (IQR), °C	41.0 (40.0-41.8)	41.0 (40.0-42.0)	41.0 (40.0-41.6)	0.497
Complaints and symptoms on admission, n (%)
Fever	296 (67.4)	76 (70.4)	220 (66.5)	0.452
Altered mental state or behavior	205 (46.7)	41 (38.0)	164 (49.5)	0.036
Dry skin or excessive sweating	45 (10.3	20 (18.5)	25 (7.6)	0.001
Rubefaction	17 (3.9)	9 (8.3)	8 (2.4)	0.006
Fast pulse	99 (22.6)	34 (31.5)	65 (19.6)	0.105
Polypnea	122 (27.8)	31 (28.7)	91 (27.5)	0.807
Headache	7 (1.6)	2 (18.5)	5 (1.5)	0.805
Syncope	207 (47.2)	70 (64.8)	137 (41.4)	< 0.001
Other	61 (13.9)	71 (65.7)	40 (12.1)	< 0.001
Laboratory findings, median (IQR)
PaO2/FiO2 ratio	225.0 (135.5-306.5)	221.0 (148.7-308.0)	226.0 (155.0-305.5)	0.999
White-cell count, 109/L	11.7 (8.1-15.6)	11.8 (8.0-15.8)	11.7 (8.1-15.6)	0.405
Lymphocyte count, 109/L	1.7 (0.8-2.8)	1.6 (0.8-2.8)	1.8 (0.8-28)	0.279
Platelet count, 109/L	92.0 (56.0-138.0)	83.5 (55.5-114.5)	97.0 (59.0-141.0)	0.143
Hemoglobin, g/L	124.0 (109.0-139.0)	121.0 (108.3-135.8)	125.0 (110.0-139.0)	0.053
Albumin, g/L	35.3 (32.5-38.9)	34.5 (31.8-38.0)	35.3 (32.5-38.9)	0.028
EN support
Early (< 48 h) EN, n (%)	68 (15.5)	13 (12.0)	55 (16.6)	0.253
Average EN calorie, median (IQR), kcal/d	1000.0 (750.0-1500.0)	1000.0 (750.0-1500.0)	1000.0 (750.0-1500.0)	0.559
Average EN protein, median (IQR), g/d	28.0 (17.0-56.0)	30.0 (17.0-56.0)	28.0 (20.0-56.0)	0.867
Average EN volume, median (IQR), mL/d	600.0 (150.0-1150.0)	625.0 (142.5-1200.0)	600.0 (150.0-1082.5)	0.31
Complications, n (%)
Disturbance of water and electrolyte	271 (61.7)	89 (82.4)	187 (56.5)	< 0.001
Rhabdomyolysis	81 (18.5)	31 (28.7)	50 (15.1)	0.002
Myocardial damage	216 (49.2)	63 (58.0)	153 (46.2)	0.029
Disseminated intravascular coagulation	172 (39.2)	54 (50.0)	118 (35.6)	0.001
Acute respiratory distress syndrome	226 (51.5)	62 (57.4)	164 (49.5)	0.156
Acute kidney injury	233 (53.1)	77 (71.3)	156 (47.1)	< 0.001
Acute liver function impairment	332 (75.6)	73 (65.6)	159 (48.0)	< 0.001
Central nervous system damage	206 (46.9)	65 (60.2)	141 (42.6)	0.001
Clinical outcomes at data cutoff, n (%)
Hospital discharge	210 (47.8)	51 (47.2)	159 (48.0)	0.234
Death	123 (28.0)	24 (22.2)	99 (29.9)	0.122
Still hospitalization	78 (17.8)	24 (22.2)	54 (16.3)	0.163
Transferred to another hospital	28 (6.4)	9 (8.3)	19 (5.7)	0.338

¹The denominators of patients who were included in the analysis are provided if they differed from the overall numbers in the group. Percentages may not total 100 because of rounding.

²Nausea/vomiting, diarrhea, flatulence, or bloody stools are defined as gastrointestinal symptoms.

IQR: Interquartile range; GCS: Glasgow coma scale; NRS: Nutrition risk screening; GI: Gastrointestinal; EN: Enteral nutrition; ICU: Intensive care unit.

Table 3 Characteristics of the heatstroke patients with endotracheal intubation, according to received enteral nutrition within 48 h after intensive care unit admission or not¹

	All intubated patients (n = 439)	EN therapy whether ≤ 48 h		P value
		Yes (n = 139)	No (n = 300)
Characteristic
Age, median (IQR), yr	71.0 (63.0-80.0)	72.0 (63.0-80.0)	71.0 (63.0-79.0)	0.801
Female sex, n (%)	197 (44.9)	62 (46.8)	135 (43.6)	0.938
GCS score at ICU admission, median (IQR)	4.0 (3.0-5.0)	5.0 (3.0-7.0)	4.0 (3.0-5 .0)	0.002
NRS score at ICU admission, median (IQR)	4.0 (3.0-5.0)	5.0 (4.0-6.0)	4.0 (3.0-5.0)	0.017
Body temperature on admission
Patients, n (%)	439 (100.0)	139 (100.0)	300 (100.0)	—
Temperature, median (IQR), °C	41.0 (40.0-41.8)	41.0 (40.0-41.5)	41.0 (40.0-42.0)	0.154
Laboratory findings, median (IQR)
PaO2/FiO2 ratio	225.0 (135.5-306.5)	226.0 (164.0-287.0)	223.0 (128.0-316.0)	0.825
White-cell count, 109/L	11.7 (8.1-15.6)	12.4 (8.6-16.8)	11.3 (8.0-15.0)	0.290
Lymphocyte count, 109/L	1.7 (0.8-2.8)	1.5 (0.7-2.3)	1.9 (0.9-3.0)	0.105
Platelet count, 109/L	92.0 (56.0-138.0)	101.0 (66.8-147.3)	88.0 (54.0-130.0)	0.039
Hemoglobin, g/L	124.0 (109.0-139.0)	122.0 (109.0-136.0)	124.5 (109.0-140.0)	0.311
Albumin, g/L	35.3 (32.5-38.9)	35.1 (32.0-38.5)	35.4 (32.5-39.0)	0.544
GI symptoms2, n (%)
Total patients	85 (19.4)	18 (12.9)	67 (22.3)	0.021
Diarrhea	60 (13.7)	13 (9.4)	47 (15.7)	0.073
Flatulence	25 (5.7)	7 (5.0)	18 (6.0)	0.685
Nausea/vomiting	14 (3.2)	7 (5.0)	7 (2.3)	0.134
Bloody stools	8 (1.8)	0 (0.0)	8 (2.6)	0.052
Complications, n (%)
Disturbance of water and electrolyte	271 (61.7)	79 (56.8)	192 (64.0)	0.151
Rhabdomyolysis	81 (18.5)	20 (11.6)	61 (20.3)	0.135
Myocardial damage	216 (49.2)	65 (46.8)	151 (50.3)	0.486
Disseminated intravascular coagulation	172 (39.2)	50 (36.0)	122 (40.7)	0.349
Acute respiratory distress syndrome	226 (51.5)	74 (53.2)	152 (50.7)	0.616
Acute kidney injury	233 (53.1)	66 (47.5)	167 (55.7)	0.110
Acute liver function impairment	332 (75.6)	74 (53.2)	258 (86.0)	< 0.001
Central nervous system damage	206 (46.9)	62 (44.6)	144 (48.0)	0.507
Treatments
Use of continuous renal-replacement therapy, n (%)	34 (7.7)	10 (8.1)	20 (7.5)	0.826
Length of ICU stay, median (IQR), d	2.0 (1.0-3.0)	2.0 (1.0-3.0)	3.0 (2.0-5.0)	< 0.001
Clinical outcomes at data cutoff, n (%)
Hospital discharge	210 (47.8)	68 (48.9)	142 (47.3)	0.757
Death	123 (28.0)	24 (17.3)	99 (33.3)	< 0.001
Still hospitalization	78 (17.8)	36 (25.9)	42 (14.0)	0.002
Transferred to another hospital	28 (6.4)	11 (7.9)	17 (5.7)	0.370

¹The denominators of patients who were included in the analysis are provided if they differed from the overall numbers in the group. Percentages may not total 100 because of rounding.

²Nausea/vomiting, diarrhea, flatulence, or bloody stools are defined as gastrointestinal symptoms.

IQR: Interquartile range; GCS: Glasgow coma scale; NRS: Nutrition risk screening; GI: Gastrointestinal; ICU: Intensive care unit.

Table 4 Characteristics of the heatstroke patients with endotracheal intubation, according to received full enteral nutrition after intensive care unit admission or not¹

	All intubated patients (n = 439)	Full EN whether		P value
		Yes (n = 173)	No (n = 266)
Characteristic
Age, median (IQR), yr	71.0 (63.0-80.0)	72.0 (63.0-80.0)	71.0 (63.0-79.0)	0.801
Female sex, n (%)	197 (44.9)	81 (46.8)	116 (43.6)	0.509
GCS score at ICU admission, median (IQR)	4.0 (3.0-5.0)	6.0 (4.0-8.0)	5.0 (3.0-7.0)	0.002
NRS score at ICU admission, median (IQR)	4.0 (3.0-5.0)	4.5 (4.0-5.0)	4.0 (3.0-5.0)	0.193
Body temperature on admission
Patients, n (%)	439 (100.0)	173 (100.0)	266 (100.0)	—
Temperature, median (IQR), °C	41.0 (40.0-41.8)	41.0 (40.0-41.4)	41.0 (40.0-42.0)	0.128
Laboratory findings, median (IQR)
PaO2/FiO2 ratio	225.0 (135.5-306.5)	246.0 (191.0-334.0)	222.0 (134.0-315.0)	0.226
White-cell count, 109/L	11.7 (8.1-15.6)	12.6 (9.4-16.7)	11.4 (8.0-15.3)	0.287
Lymphocyte count, 109/L	1.7 (0.8-2.8)	0.8 (0.5-1.6)	2.0 (0.9-3.0)	0.084
Platelet count, 109/L	92.0 (56.0-138.0)	71.5 (37.0-113.8)	89.0 (54.0-132.5)	0.011
Hemoglobin, g/L	124.0 (109.0-139.0)	119.0 (107.5-129.0)	125.0 (110.0-140.0)	0.002
Albumin, g/L	35.3 (32.5-38.9)	32.0 (29.0-35.2)	35.5 (32.5-39.2)	< 0.001
GI symptoms2, n (%)
Total patients	85 (19.4)	25 (14.5)	60 (22.6)	0.036
Diarrhea	60 (13.7)	17 (9.8)	43 (16.2)	0.059
Flatulence	25 (5.7)	8 (4.6)	17 (6.4)	0.435
Nausea/vomiting	14 (3.2)	7 (4.0)	7 (2.6)	0.409
Bloody stools	8 (1.8)	0 (0.0)	8 (3.1)	0.021
Complications, n (%)
Disturbance of water and electrolyte	271 (61.7)	105 (60.7)	166 (62.4)	0.718
Rhabdomyolysis	81 (18.5)	20 (11.6)	55 (20.7)	0.013
Myocardial damage	216 (49.2)	83 (48.0)	133 (50.0)	0.678
Disseminated intravascular coagulation	172 (39.2)	60 (34.7)	112 (42.1)	0.119
Acute respiratory distress syndrome	226 (51.5)	92 (53.2)	134 (50.4)	0.566
Acute kidney injury	233 (53.1)	79 (45.7)	154 (57.9)	0.012
Acute liver function impairment	332 (75.6)	94 (54.3)	138 (51.9)	0.615
Central nervous system damage	206 (46.9)	80 (46.2)	126 (47.4)	0.817
Treatments
Use of continuous renal-replacement therapy, n (%)	34 (7.7)	14 (8.1)	20 (7.5)	0.826
Length of ICU stay, median (IQR), d	2.0 (1.0-3.0)	2.0 (1.0-2.0)	3.0 (1.0-4.0)	< 0.001
Clinical outcomes at data cutoff, n (%)
Hospital discharge	210 (47.8)	83 (48.0)	127 (47.7)	0.962
Death	123 (28.0)	29 (16.8)	94 (35.3)	< 0.001
Still hospitalization	78 (17.8)	46 (26.6)	82 (20.8)	0.339
Transferred to another hospital	28 (6.4)	15 (8.7)	13 (4.9)	0.113

¹The denominators of patients who were included in the analysis are provided if they differed from the overall numbers in the group. Percentages may not total 100 because of rounding.

²Nausea/vomiting, diarrhea, flatulence, or bloody stools are defined as gastrointestinal symptoms.

IQR: Interquartile range; GCS: Glasgow coma scale; NRS: Nutrition risk screening; GI: Gastrointestinal; ICU: Intensive care unit.

Table 5 Clinical characteristics of the study patients, according to types of gastrointestinal symptoms¹

	GI Symptoms2			P value
	Diarrhea (n = 88)	Flatulence (n = 27)	Nausea/vomiting (n = 15)
Characteristic
Age, median (IQR), yr	65.0 (56.0-76.0)	69.0 (56.0-79.0)	68.0 (57.5-78.0)	0.565
Female sex, n (%)	35.0 (39.8)	14.0 (51.8)	6 (40.0)	0.529
GCS score at ICU admission, median (IQR)	5.0 (3.0-7.0)	6.0 (3.0-9.5)	4.0 (3.0-6.0)	0.540
NRS score at ICU admission, median (IQR)	4.0 (3.0-5.0)	4.5 (4.0-5.0)	4.0 (3.0-5.0)	0.193
Body temperature admission
Patients, n (%)	88.0 (100.0)	27.0 (100.0)	15.0 (100.0)	—
Temperature, median (IQR), °C	41.0 (40.0-42.0)	40.0 (39.8-41.0)	40.1 (39.8-41.0)	0.003
Complaints and symptoms, n (%)
Fever	62.0 (70.5)	20.0 (74.0)	8.0 (53.3)	0.343
Altered mental state or behavior	35.0 (39.8)	13.0 (48.1)	4.0 (26.7)	0.395
Dry skin or excessive sweating	19.0 (21.6)	2.0 (7.4)	2.0 (13.3)	0.215
Rubefaction	7.0 (8.0)	2.0 (7.4)	1.0 (6.7)	0.983
Fast pulse	32.0 (36.4)	6.0 (22.2)	4.0 (26.7)	0.344
Polypnea	29.0 (33.0)	6.0 (22.2)	3.0 (20.0)	0.397
Headache	1.0 (1.1)	3.0 (11.1)	0.0 (0.0)	0.024
Syncope	63.0 (71.6)	13.0 (48.1)	8.0 (53.3)	0.052
Other	22.0 (25.0)	4.0 (14.8)	2.0 (13.3)	0.378
Laboratory findings, median (IQR)
White-cell count, 109/L	13.0 (8.2-16.3)	13.0 (8.2-16.3)	13.0 (8.2-16.3)	0.210
Hemoglobin, g/L	122.0 (110.3-136.0)	125.0 (110.5-137.5)	120.0 (107.3-130.0)	0.589
Albumin, g/L	35.8 (32.9-38.8)	35.3 (32.0-39.5)	36.7 (29.3-39.5)	0.969
Complications, n (%)
Disturbance of water and electrolyte	63 (71.6)	20 (74.0)	11 (73.3)	0.085
Rhabdomyolysis	24 (27.3)	6 (22.2)	4 (26.7)	0.003
Myocardial damage	49 (55.7)	11.0 (40.7)	9 (60.0)	0.008
Disseminated intravascular coagulation	40 (45.5)	9 (33.3)	6 (40.0)	0.010
Acute respiratory distress syndrome	46 (52.3)	9 (33.3)	6 (40.0)	0.012
Acute kidney injury	52 (59.1)	15 (55.6)	10 (66.7)	0.024
Acute liver function impairment	52 (59.1)	15 (55.6)	10 (66.7)	0.024
Central nervous system damage	48 (54.5)	15 (55.6)	9 (60.0)	0.019
Treatments
Use of continuous renal-replacement therapy, n (%)	7 (8.0)	3 (11.1)	2 (13.3)	< 0.001
Length of ICU stay, median (IQR), d	1.0 (1.0-2.0)	1.0 (1.0-1.0)	2.0 (1.0-3.0)	0.015
Clinical outcomes at data cutoff, n (%)
Hospital discharge	44.0 (50.0)	11.0 (40.7)	5.0 (33.3)	0.400
Death	16.0 (18.2)	2.0 (7.4)	4.0 (26.7)	0.240
Still hospitalization	19.0 (21.6)	13.0 (48.1)	5.0 (33.3)	0.025
Transferred to another hospital	9.0 (10.2)	1.0 (3.7)	1.0 (6.7)	0.547

¹The denominators of patients who were included in the analysis are provided if they differed from the overall numbers in the group. Percentages may not total 100 because of rounding.

²Nausea/vomiting, diarrhea, flatulence, or bloody stools are defined as gastrointestinal symptoms.

IQR: Interquartile range; GCS: Glasgow coma scale; NRS: Nutrition risk screening; GI: Gastrointestinal; ICU: Intensive care unit.

Table 6 Heat stroke patient characteristics according to the time of onset of gastrointestinal symptoms

	GI symptoms1		P value
	On admission (n = 68)	Developed in ICU stay (n = 64)
Characteristic
Age, median (IQR), yr	67.0 (57.0-76.0)	70.0 (64.0-80.0)	0.050
Female sex, n (%)	28 (41.2)	32 (50.0)	0.310
BMI, median (IQR), kg/m2	22.7 (20.2-24.8)	21.1 (20.0-23.3)	0.050
GCS score at ICU admission, median (IQR)	5.0 (3.0-8.0)	5.0 (3.0-7.0)	0.814
NRS score at ICU admission, median (IQR)	3.0 (3.0-4.5)	4.0 (3.0-6.0)	0.009
Fever on admission
Patients, n (%)	68 (100.0)	64 (100.0)	—
Temperature, median (IQR), °C	41.0 (40.0-42.0)	41.0 (40.0-41.3)	0.265
Complaints and symptoms on admission, n (%)
Fever	54 (79.4)	39 (60.9)	0.020
Altered mental state or behavior	25 (36.8)	30 (46.9)	0.239
Dry skin or excessive sweating	13 (19.1)	7 (109)	0.190
Rubefaction	5 (7.4)	6 (9.4)	0.674
Fast pulse	27 (39.7)	13 (20.3)	0.015
Polypnea	24 (35.3)	14 (21.9)	0.089
Headache	1 (1.5)	2 (3.1)	0.524
Syncope	49 (72.1)	36 (56.2)	0.058
Other	20 (29.4)	7 (109)	0.009
Coexisting disorder, n (%)
Diabetes	1 (1.5)	9 (14.1)	0.009
Hypertension	15 (22.1)	21 (32.8)	0.166
Chronic obstructive pulmonary disease	11 (16.2)	10 (15.6)	0.931
Chronic cardiac insufficiency	5 (7.4)	11 (17.2)	0.084
Hepatitis B infection	1 (1.5)	0 (0.0)	0.330
Cancer	1 (1.5)	2 (3.1)	0.524
Chronic renal disease	0 (0.0)	2 (3.1)	0.142
Immunodeficiency	1 (1.5)	2 (3.1)	0.524
Laboratory findings
PaO2/FiO2 ratio	240.0 (141.8-316.0)	217.0 (165.0-285.8)	0.775
White-cell count, 109/L	12.1 (7.8-16.2)	11.8 (8.2-14.2)	0.667
Lymphocyte count, 109/L	2.1 (1.0-3.3)	1.2 (0.6-2.0)	0.023
Platelet count, 109/L	90.0 (60.5-120.3)	98.5 (67.8-150.5)	0.256
Hemoglobin, g/L	126.0 (112.0-135.5)	118.5 (103.5-137.5)	0.106
Albumin, g/L	36.5 (33.3-40.0)	35.0 (32.1-38.6)	0.093
Other findings, median (IQR)
C-reactive protein, mg/L	5.0 (0.5-10.0)	5.0 (1.0-14.9)	0.605
Procalcitonin, ng/mL	1.4 (0.4-8.2)	9.3 (2.2-29.3)	0.055
Lactate dehydrogenase, U/L	465.0 (314.3-810.3)	382.5 (282.8-537.8)	0.263
Aspartate aminotransferase, U/L	123.9 (58.3-272.3)	107.2 (44.0-268.3)	0.152
Alanine aminotransferase, U/L	46.5 (26.2-112.4)	48.0 (27.1-89.5)	0.247
Total bilirubin, μmol/L	18.5 (12.8-25.9)	15.6 (10.1-23.0)	0.211
CK-Mb, U/L	10.1 (2.9-33.1)	8.7 (3.3-41.0)	0.214
Creatinine, μmol/L	131.1 (105.3-182.8)	137.0 (97.5-171.0)	0.628
D-dimer, mg/L	3.9 (2.5-11.5)	4.6 (1.9-12.7)	0.524
Minerals, median (IQR), mmol/L
Sodium	132.0 (129.0-137.0)	133.9 (128.5-136.8)	0.959
Potassium	3.3 (3.0-3.9)	3.5 (2.9-3.8)	0.849
Lactate	4.2 (3.1-5.5)	3.6 (2.4-5.3)	0.649
Complication, n (%)
Disturbance of water and electrolyte	51 (75.0)	44 (68.8)	0.424
Rhabdomyolysis	21 (30.9)	13 (20.3)	0.165
Myocardial damage	40 (58.8)	30 (46.9)	0.122
Disseminated intravascular coagulation	38 (55.9)	24 (37.5)	0.034
Acute respiratory distress syndrome	39 (57.4)	27 (42.2)	0.082
Acute kidney injury	45 (66.2)	38 (59.4)	0.419
Acute liver function impairment	41 (60.3)	40 (62.5)	0.795
Central nervous system damage	42 (61.8)	30 (46.9)	0.086
Clinical outcomes at data cutoff, n (%)
Hospital discharge	35 (51.5)	29 (45.3)	0.479
Death	17 (25.0)	9 (14.1)	0.114
Still hospitalization	13 (19.1)	20 (31.3)	0.108
Transferred to another hospital	3 (4.4)	6 (9.4)	0.258

¹Nausea/vomiting, diarrhea, flatulence, or bloody stools are defined as gastrointestinal symptoms.

IQR: Interquartile range; CK-Mb: Creatine kinase; GI: Gastrointestinal; ICU: Intensive care unit; BMI: Body mass index.

Table 7 Heat stroke patient characteristics according to the time of onset of gastrointestinal symptoms¹

	Early onset, n = 41	Late onset, n = 23	P value
Characteristic2
Age, median (IQR), yr	69.0 (62.3-79.0)	64.0 (56.0-76.0)	0.856
Female sex, n (%)	23 (56.1)	8 (34.8)	0.102
Fever on admission
Patients, n (%)	41 (100.0)	23 (100.0)	—
Temperature, median (IQR), °C	41.0 (40.0-42.0)	40.7 (39.6-41.3)	0.338
Body temperature on admission, n (%)
Fever	23 (56.1)	15 (65.2)	0.475
Altered mental state or behavior	19 (46.3)	11 (47.8)	0.909
Dry skin or excessive sweating	4 (9.8)	3 (13.0)	0.686
Rubefaction	4 (9.8)	2 (8.7)	0.889
Fast pulse	11 (26.8)	2 (8.7)	0.084
Polypnea	9 (22.0)	5 (21.7)	0.984
Headache	2 (4.9)	0 (0.0)	0.282
Syncope	21 (51.2)	13 (56.5)	0.683
Other	3 (7.3)	4 (17.4)	0.215
EN support
EN, n (%)	29 (70.7)	22 (95.7)	< 0.001
Average EN calorie, median (IQR), kcal/d	752.0 (500.0-1007.5)	1292.0 (750.0-1560.0)	< 0.001
Average EN protein, median (IQR), g/d	20.0 (17.6-32.5)	28.0 (15.0-57.0)	0.003
Average EN volume, median (IQR), ml/d	600.0 (147.5-1000.0)	900.0 (461.2-1500.0)	< 0.001
Duration of EN, median (IQR), d	3.0 (1.8-5.0)	7.0 (4.0-11.0)	0.011
Laboratory findings, median (IQR)
White-cell count, 109/L	10.6 (7.8-13.5)	13.5 (8.6-15.8)	0.351
Hemoglobin, g/L	117.0 (106.0-128.0)	128.5 (105.3-141.5)	0.187
Albumin, g/L	35.4 (33.7-39.2)	34.4 (30.8-36.8)	0.239
Complications, n (%)
Disturbance of water and electrolyte	26 (63.4)	17 (73.9)	0.391
Rhabdomyolysis	6 (14.6)	6 (26.1)	0.261
Hemorrhage of digestive tract	8 (19.5)	3 (13.1)	0.511
Myocardial damage	17 (41.5)	12 (52.2)	0.409
Disseminated intravascular coagulation	14 (34.1)	9 (39.1)	0.691
Acute respiratory distress syndrome	17 (41.5)	6 (26.1)	0.855
Clinical outcomes at data cutoff, n (%)
Hospital discharge	17 (41.5)	11 (47.8)	0.622
Death	7 (17.1)	2 (8.7)	0.355
Still hospitalization	12 (29.3)	8 (34.8)	0.648
Transferred to another hospital	4 (9.8)	2 (8.7)	0.889

¹Nausea/vomiting, diarrhea, flatulence, or bloody stools are defined as gastrointestinal symptoms.

²The denominators of patients who were included in the analysis are provided if they differed from the overall numbers in the group. Percentages may not total 100 because of rounding.

IQR: Interquartile range; EN: Enteral nutrition.

Table 8 Heat stroke patient characteristics according to duration of gastrointestinal symptoms¹

	Last < 4 d, n = 96	Last ≥ 4 d, n = 36	P value
Characteristic
Age, median (IQR), yr	70.0 (61.5-78.3)	67.0 (59.0-76.0)	0.659
Female sex, n (%)	43 (44.8)	17 (47.2)	0.803
Body temperature on admission
Patients, n (%)	96 (100.0)	36 (100.0)	-
Temperature, median (IQR), °C	41.0 (40.0-41.5)	41.0 (40.0-42.0)	0.948
Complaints and symptoms on admission, n (%)
Fever	69 (71.9)	24 (66.7)	0.559
Altered mental state or behavior	39 (40.6)	16 (44.4)	0.692
Dry skin or excessive sweating	16 (16.7)	4 (11.1)	0.428
Rubefaction	9 (9.4)	2 (5.6)	0.889
Fast pulse	32 (33.3)	8 (22.2)	0.767
Polypnea	31 (32.3)	7 (19.4)	0.147
Headache	2 (2.1)	1 (2.8)	0.811
Syncope	67 (69.8)	18 (50.0)	0.034
Other	19 (19.8)	8 (22.2)	0.758
Laboratory findings, median (IQR)
White-cell count, 109/L	11.0 (7.5-14.2)	7.3 (9.2-16.3)	0.062
Hemoglobin, g/L	122.0 (110.5-135.5)	118.0 (106.0-132.5)	0.941
Albumin, g/L	37.0 (33.3-39.7)	34.4 (31.1-36.4)	0.031
Complications, n (%)
Disturbance of water and electrolyte	69 (71.9)	20 (55.6)	0.075
Rhabdomyolysis	28 (29.2)	6 (16.7)	0.144
Hemorrhage of digestive tract	28 (29.2)	7 (19.4)	0.26
Myocardial damage	50 (52.1)	20 (55.6)	0.722
Disseminated intravascular coagulation	27 (27.8)	20 (54.2)	0.007
Acute respiratory distress syndrome	12 (12.0)	20 (54.2)	< 0.001
Clinical outcomes at data cutoff, n (%)
Hospital discharge	54 (56.3)	10 (27.8)	0.004
Death	17 (17.7)	9 (25.0)	0.348
Still hospitalization	21 (21.9)	12 (33.3)	0.176
Transferred to another hospital	4 (4.2)	5 (13.9)	0.048

¹Nausea/vomiting, diarrhea, flatulence, or bloody stools are defined as gastrointestinal symptoms.

IQR: Interquartile range.