Introduction
Materials and methods
Study design
Study patients and variables
Outcome measures
Statistical analysis
Results
Characteristics of the study population
Baseline characteristics
|
After propensity matching
| |||||||||
---|---|---|---|---|---|---|---|---|---|---|
Total
|
Surface group
|
Endovascular group
|
P
value
|
STDa
|
Total
|
Surface group
|
Endovascular group
|
P
value
|
STDb
| |
(
N
= 803)
|
(
n
= 559)
|
(
n
= 244)
|
(
N
= 360)
|
(
n
= 180)
|
(
n
= 180)
| |||||
Demographic characteristics | ||||||||||
Male | 561 (69.9) | 391 (70.0) | 170 (69.7) | 0.94 | −0.65 | 244 (67.8) | 119 (66.1) | 125 (69.4) | 0.50 | 7.06 |
Age (years) | 56.9 ± 16.1 | 57.2 ± 16.1 | 56.0 ± 16.0 | 0.32 | 6.10 | 55.7 ± 16.9 | 56.0 ± 17.2 | 55.5 ± 16.6 | 0.78 | 2.40 |
Underlying disease | ||||||||||
Ischemic heart disease | 102 (12.7) | 71 (12.7) | 31 (12.7) | 1.00 | 0.00 | 48 (13.3) | 23 (12.8) | 25 (13.9) | 0.76 | 3.23 |
Cerebrovascular disease | 33 (4.1) | 24 (4.3) | 9 (3.7) | 0.69 | −3.06 | 18 (5.0) | 11 (6.1) | 7 (3.9) | 0.33 | −10.11 |
Hypertension | 270 (33.6) | 192 (34.4) | 78 (32.0) | 0.51 | −5.10 | 119 (33.1) | 61 (33.9) | 58 (32.2) | 0.74 | −3.61 |
Diabetes mellitus | 180 (22.4) | 118 (21.1) | 62 (25.4) | 0.18 | 10.19 | 86 (23.9) | 44 (24.4) | 42 (23.3) | 0.81 | −2.58 |
Lung disease | 51 (6.4) | 37 (6.6) | 14 (5.7) | 0.64 | −3.75 | 21 (5.8) | 11 (6.1) | 10 (5.6) | 0.82 | −2.13 |
Renal disease | 52 (6.5) | 33 (5.9) | 19 (7.8) | 0.32 | 7.53 | 27 (7.5) | 14 (7.8) | 13 (7.2) | 0.84 | −2.28 |
CPR variables | ||||||||||
Witnessed | 541 (67.5) | 364 (65.2) | 177 (72.5) | 0.04 | 15.81 | 244 (67.8) | 122 (67.8) | 122 (67.8) | 1.00 | 0.00 |
Bystander CPR | 245 (31.9) | 151 (27.9) | 94 (41.2) | <0.01 | 28.25 | 88 (26.8) | 42 (25.6) | 46 (27.9) | 0.64 | 5.20 |
Shockable rhythm | 199 (24.9) | 125 (22.5) | 74 (30.6) | 0.02 | 18.42 | 85 (23.9) | 38 (21.4) | 47 (26.4) | 0.26 | 11.74 |
Anoxic timec (minutes) | 32.6 ± 18.4 | 32.8 ± 18.9 | 32.1 ± 17.4 | 0.65 | 3.10 | 32.8 ± 19.1 | 32.7 ± 20.1 | 32.9 ± 18.1 | 0.93 | −0.84 |
Cardiac cause | 498 (62.0) | 335 (59.9) | 163 (66.8) | 0.07 | 14.36 | 231 (64.2) | 114 (63.3) | 117 (65.0) | 0.74 | 3.55 |
Variables after ROSC | ||||||||||
STEMI | 73 (9.1) | 48 (5.6) | 25 (10.3) | 0.45 | 5.81 | 27 (7.5) | 14 (7.8) | 13 (7.2) | 0.84 | −2.28 |
Spontaneous breathing | 325 (41.4) | 196 (35.8) | 129 (54.2) | <0.01 | 37.63 | 182 (51.7) | 94 (53.4) | 88 (50.0) | 0.52 | −6.81 |
Motor response | 135 (17.0) | 83 (14.9) | 52 (21.9) | 0.02 | 18.14 | 71 (19.9) | 37 (20.7) | 34 (19.1) | 0.71 | −4.01 |
Pupil light reflex | 343 (43.4) | 238 (42.9) | 105 (44.7) | 0.64 | 3.63 | 174 (49.7) | 88 (50.0) | 86 (49.4) | 0.91 | −1.20 |
Hospital variable | ||||||||||
TH volume | 90.2 ± 61.5 | 70.4 ± 55.2 | 135.6 ± 50.0 | <0.01 | −99.46 | 129.4 ± 55.9 | 130.1 ± 58.5 | 128.6 ± 53.3 | 0.80 | 2.16 |
Outcomes for unmatched patients
Total (
N
= 803)
|
Surface group
|
Endovascular group
|
P
value
| |
---|---|---|---|---|
(
n
= 559)
|
(
n
= 244)
| |||
Time variables | ||||
Induction time (minutes) | 231.1 ± 9.1 | 240.1 ± 11.8 | 211.1 ± 12.9 | 0.10 |
≥165 minutes (cutoff value: median) | 395 (51.1) | 269 (50.3) | 126 (52.9) | 0.50 |
Rewarming time (minutes) | 745.9 ± 17.8 | 744.3 ± 23.1 | 749.5 ± 25.7 | 0.88 |
≥720 minutes (cutoff value: median) | 353 (50.4) | 232 (47.8) | 121 (56.3) | 0.04 |
Adverse events in the cooling phase | ||||
Overcooling | 151 (18.8) | 131 (23.5) | 20 (8.2) | <0.01 |
Bradycardia | 106 (13.3) | 84 (15.1) | 22 (9.0) | 0.02 |
Tachycardia | 99 (12.4) | 81 (14.5) | 18 (7.5) | 0.01 |
Hypokalemia | 234 (29.3) | 170 (30.6) | 64 (26.3) | 0.22 |
Hyperglycemia | 369 (46.1) | 295 (53.0) | 74 (30.3) | <0.01 |
Bleeding | 26 (3.3) | 20 (3.6) | 6 (2.5) | 0.42 |
Hypotension | 280 (35.0) | 209 (37.6) | 71 (29.1) | 0.02 |
Adverse events in the rewarming phase | ||||
Hyperthermia | 80 (10.7) | 67 (13.0) | 13 (5.6) | <0.01 |
Arrhythmia | 42 (5.7) | 37 (7.2) | 5 (2.2) | 0.01 |
Hyperkalemia | 56 (7.5) | 39 (7.6) | 17 (7.4) | 0.91 |
Hypoglycemia | 73 (9.8) | 55 (10.7) | 18 (7.8) | 0.22 |
Bleeding | 12 (1.6) | 7 (1.4) | 5 (2.2) | 0.53 |
Hypotension | 180 (24.2) | 133 (25.9) | 47 (20.4) | 0.10 |
Adverse events in critical care | ||||
Sepsis | 59 (7.5) | 40 (7.3) | 19 (7.8) | 0.80 |
Pneumonia | 283 (35.6) | 191 (34.6) | 92 (38.0) | 0.36 |
Neurological outcome | ||||
Hospital mortality | 310 (38.6) | 218 (39.0) | 92 (37.7) | 0.73 |
Poor neurological outcome | 574 (71.5) | 416 (74.4) | 158 (64.7) | 0.01 |
Poor neurological outcome
|
Hospital mortality
| |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
OR
|
95% CI
|
P
value
|
Adjusted OR
|
95% CI
|
P
value
|
OR
|
95% CI
|
P
value
|
Adjusted OR
|
95% CI
|
P
value
| |
Method | ||||||||||||
Surface cooling | 1.58 | 1.15 to 2.19 | 0.01 | 1.46 | 0.81 to 2.63 | 0.21 | 1.06 | 0.78 to 1.44 | 0.73 | 0.78 | 0.50 to 1.21 | 0.26 |
Demographic characteristics | ||||||||||||
Male | 0.50 | 0.35 to 0.72 | <0.01 | 0.63 | 0.37 to 1.06 | 0.08 | 0.56 | 0.41 to 0.76 | <0.01 | 0.67 | 0.47 to 0.96 | 0.03 |
Age | 1.04 | 1.03 to 1.05 | <0.01 | 1.04 | 1.02 to 1.06 | <0.01 | 1.02 | 1.01 to 1.03 | <0.01 | 1.02 | 1.00 to 1.03 | 0.01 |
≥57 years old | 3.04 | 2.20 to 4.20 | <0.01 | 1.92 | 1.44 to 2.57 | <0.01 | ||||||
Underlying disease | ||||||||||||
Ischemic heart disease | 0.77 | 0.50 to 1.20 | 0.25 | 0.85 | 0.55 to 1.31 | 0.46 | ||||||
Cerebrovascular disease | 2.30 | 0.88 to 6.03 | 0.09 | 1.96 | 0.98 to 3.96 | 0.06 | ||||||
Hypertension | 1.63 | 1.16 to 2.28 | 0.01 | 1.29 | 0.72 to 2.31 | 0.40 | 1.29 | 0.95 to 1.73 | 0.10 | |||
Diabetes mellitus | 2.59 | 1.67 to 4.00 | <0.01 | 1.68 | 0.86 to 3.29 | 0.13 | 1.94 | 1.39 to 2.72 | <0.01 | 1.54 | 1.02 to 2.33 | 0.04 |
Lung disease | 5.02 | 1.79 to 14.09 | <0.01 | 3.09 | 0.82 to 11.65 | 0.10 | 1.22 | 0.69 to 2.17 | 0.49 | |||
Renal disease | 5.13 | 1.83 to 14.41 | <0.01 | 1.48 | 0.43 to 5.13 | 0.54 | 2.11 | 1.20 to 3.72 | 0.01 | 1.09 | 0.56 to 2.15 | 0.80 |
CPR variables | ||||||||||||
Witnessed | 0.36 | 0.25 to 0.53 | <0.01 | 0.58 | 0.34 to 1.01 | 0.05 | 0.43 | 0.31 to 0.58 | <0.01 | 0.60 | 0.42 to 0.85 | 0.01 |
Bystander CPR | 1.96 | 1.41 to 2.72 | <0.01 | 1.22 | 0.72 to 2.04 | 0.46 | 0.78 | 0.57 to 1.07 | 0.12 | |||
Shockable rhythm | 0.51 | 0.37 to 0.71 | <0.01 | 0.51 | 0.30 to 0.87 | 0.01 | 0.33 | 0.22 to 0.48 | <0.01 | 0.62 | 0.39 to 0.99 | 0.05 |
Anoxic timea
| 1.03 | 1.02 to 1.04 | <0.01 | 1.05 | 1.03 to 1.06 | <0.01 | 1.02 | 1.01 to 1.03 | <0.01 | 1.02 | 1.01 to 1.03 | <0.01 |
≥30 minutes | 2.64 | 1.92 to 3.63 | <0.01 | 1.83 | 1.37 to 2.45 | <0.01 | ||||||
Cardiac cause | 0.14 | 0.09 to 0.22 | <0.01 | 0.19 | 0.11 to 0.35 | <0.01 | 0.37 | 0.28 to 0.50 | <0.01 | 0.55 | 0.38 to 0.79 | <0.01 |
Variables after ROSC | ||||||||||||
STEMI | 0.35 | 0.21 to 0.57 | <0.01 | 0.78 | 0.38 to 1.60 | 0.49 | 0.66 | 0.39 to 1.12 | 0.12 | |||
Spontaneous breathing | 0.19 | 0.14 to 0.27 | <0.01 | 0.41 | 0.25 to 0.67 | <0.01 | 0.27 | 0.20 to 0.38 | <0.01 | 0.46 | 0.32 to 0.68 | <0.01 |
Motor response | 0.10 | 0.07 to 0.15 | <0.01 | 0.23 | 0.13 to 0.41 | <0.01 | 0.16 | 0.09 to 0.28 | <0.01 | 0.45 | 0.24 to 0.85 | 0.01 |
Pupil light reflex | 0.11 | 0.07 to 0.15 | <0.01 | 0.26 | 0.16 to 0.42 | <0.01 | 0.21 | 0.15 to 0.30 | <0.01 | 0.43 | 0.30 to 0.64 | <0.01 |
Hospital variable | ||||||||||||
TH volume | 1.00 | 0.99 to 1.00 | <0.01 | 1.00 | 1.00 to 1.01 | 0.21 | 1.00 | 0.99 to 1.00 | <0.01 | 1.00 | 1.00 to 1.00 | 0.34 |
≥60 | 0.63 | 0.46 to 0.86 | <0.01 | 0.77 | 0.58 to 1.03 | 0.08 |
Characteristics of patients matched for propensity scores
Outcomes for matched patients
Surface cooling group
|
Endovascular cooling group
|
Odds ratio
|
95% confidence interval
|
P
value
| |
---|---|---|---|---|---|
(
n
= 180)
|
(
n
= 180)
| ||||
Time variables | |||||
Induction time (minutes) | 235.3 ± 18.0 | 209.4 ± 15.4 | 1.13 | 0.79 to 1.62 | 0.51 |
≥173.5 minutes (cutoff value: median) | 88 (50.0) | 89 (50.0) | 1.00 | 0.66 to 1.52 | 1.00 |
Rewarming time (minutes) | 625.0 ± 34.9 | 741.3 ± 32.3 | 0.50 | 0.34 to 0.73 | <0.01 |
≥660 minutes (cutoff value: median) | 68 (40.7) | 103 (65.2) | 0.37 | 0.23 to 0.58 | <0.01 |
Adverse events in the cooling phase | |||||
Overcooling | 32 (17.8) | 14 (7.8) | 2.56 | 1.32 to 4.99 | 0.01 |
Bradycardia | 16 (9.0) | 15 (8.3) | 1.09 | 0.52 to 2.27 | 0.83 |
Tachycardia | 16 (8.9) | 14 (7.9) | 1.14 | 0.54 to 2.42 | 0.73 |
Hypokalemia | 59 (32.8) | 45 (25.1) | 1.45 | 0.92 to 2.30 | 0.11 |
Hyperglycemia | 104 (57.8) | 58 (32.2) | 1.54 | 1.00 to 2.36 | 0.05 |
Bleeding | 3 (1.7) | 5 (2.9) | 0.59 | 0.14 to 2.49 | 0.45 |
Hypotension | 72 (40.2) | 58 (32.2) | 1.42 | 0.92 to 2.18 | 0.12 |
Adverse events in the rewarming phase | |||||
Hyperthermia | 23 (13.5) | 10 (5.9) | 2.49 | 1.15 to 5.40 | 0.02 |
Arrhythmia | 5 (2.9) | 5 (3.0) | 0.98 | 0.28 to 3.46 | 0.98 |
Hyperkalemia | 19 (11.1) | 14 (8.2) | 1.39 | 0.67 to 2.88 | 0.37 |
Hypoglycemia | 28 (16.4) | 15 (8.8) | 2.02 | 1.04 to 3.94 | 0.04 |
Bleeding | 1 (0.6) | 3 (1.8) | 0.32 | 0.03 to 3.12 | 0.33 |
Hypotension | 56 (32.6) | 38 (22.4) | 1.68 | 1.04 to 2.71 | 0.04 |
Adverse events in critical care | |||||
Sepsis | 13 (7.2) | 15 (8.4) | 0.85 | 0.39 to 1.84 | 0.68 |
Pneumonia | 57 (31.8) | 63 (35.4) | 0.85 | 0.55 to 1.32 | 0.48 |
Neurological outcome | |||||
Hospital mortality | 62 (34.4) | 69 (38.3) | 0.85 | 0.55 to 1.30 | 0.44 |
Poor neurological outcome | 126 (70.0) | 117 (65.0) | 1.26 | 0.81 to 1.96 | 0.31 |
Comparisons between hydrogel pads and catheter balloons
Hydrogel pads
|
Catheter balloons
|
Odds ratio
|
95% confidence interval
|
P
value
| |
---|---|---|---|---|---|
(
n
= 59)
|
(
n
= 59)
| ||||
Time variables | |||||
Induction time (minutes) | 188.1 ± 22.6 | 243.4 ± 35.3 | 0.73 | 0.39 to 1.39 | 0.34 |
≥160.0 minutes (cutoff value: median) | 26 (45.6) | 32 (56.1) | 0.66 | 0.31 to 1.37 | 0.26 |
Rewarming time (minutes) | 923.2 ± 61.1 | 697.3 ± 67.7 | 3.23 | 1.60 to 6.52 | <0.01 |
≥720 minutes (cutoff value: median) | 39 (78.0) | 23 (43.40) | 4.62 | 1.95 to 10.95 | <0.01 |
Adverse events in the cooling phase | |||||
Overcooling | 8 (13.56) | 9 (15.25) | 0.87 | 0.31 to 2.44 | 0.79 |
Bradycardia | 9 (15.25) | 7 (11.86) | 1.34 | 0.46 to 3.86 | 0.59 |
Tachycardia | 7 (11.86) | 11 (19.30) | 0.56 | 0.20 to 1.57 | 0.27 |
Hypokalemia | 16 (27.12) | 13 (22.41) | 1.29 | 0.56 to 2.99 | 0.56 |
Hyperglycemia | 34 (57.63) | 27 (45.76) | 1.61 | 0.78 to 3.34 | 0.20 |
Bleeding | 3 (5.08) | 3 (5.45) | 0.93 | 0.18 to 4.81 | 0.93 |
Hypotension | 25 (42.37) | 17 (28.81) | 1.82 | 0.85 to 3.90 | 0.13 |
Adverse events in the rewarming phase | |||||
Hyperthermia | 7 (12.73) | 1 (1.82) | 7.88 | 0.94 to 66.33 | 0.06 |
Arrhythmia | 4 (7.41) | 3 (5.66) | 1.33 | 0.28 to 6.27 | 0.72 |
Hyperkalemia | 6 (11.11) | 6 (10.91) | 1.02 | 0.31 to 3.39 | 0.97 |
Hypoglycemia | 8 (14.81) | 2 (3.64) | 4.61 | 0.93 to 22.81 | 0.06 |
Bleeding | 2 (3.70) | 2 (3.85) | 0.96 | 0.13 to 7.09 | 0.97 |
Hypotension | 19 (35.19) | 12 (21.82) | 1.95 | 0.83 to 4.55 | 0.13 |
Adverse events in critical care | |||||
Sepsis | 1 (1.69) | 8 (13.79) | 0.11 | 0.01 to 0.89 | 0.04 |
Pneumonia | 17 (28.81) | 22 (37.93) | 0.66 | 0.31 to 1.44 | 0.30 |
Neurological outcome | |||||
Hospital mortality | 26 (44.07) | 22 (37.29) | 1.33 | 0.63 to 2.77 | 0.45 |
Poor neurological outcome | 45 (76.27) | 40 (67.80) | 1.53 | 0.68 to 3.44 | 0.31 |
Discussion
Limitations
Conclusions
Key messages
-
No significant difference in neurological outcome and hospital mortality was observed between the surface and endovascular cooling methods.
-
Overcooling, rebound hyperthermia, rewarming-related hypoglycemia and rewarming-related hypotension were significantly increased in the surface cooling group compared with the endovascular cooling group.
-
These adverse events of surface cooling were not observed in the modern surface cooling method using hydrogel pads.