Table 1.
Characteristics according to baseline bystander-witnessed VF survival and Analyze Early versus Analyze Late status
| Characteristic | Baseline Survival ≤ 20% | Baseline Survival > 20% | ||
|---|---|---|---|---|
| Treatment Strategy | Analyze Early | Analyze Late | Analyze Early | Analyze Late |
| N=2291 | N=1903 | N=2673 | N=2523 | |
| EMS response interval (minutes), mean (sd) | 6.1 (2.7) | 6.0 (2.7) | 6.0 (2.8) | 6.0 (2.6) |
| Arrest witnessed, %* (n) | 45.9 (1030) | 45.8 (855) | 44.4 (1152) | 44.7 (1085) |
| Bystander CPR, %* (n) | 34.6 (799) | 35.0 (666) | 42.5 (1135) | 44.8 (1135) |
| Age (years), mean (sd) | 67.9 (16.3) | 68.0 (15.7) | 66.0 (16.8) | 66.1 (17.1) |
| Male, %* (n) | 65.4 (1499) | 64.7 (1232) | 64.1 (1713) | 63.5 (1601) |
| Public location, % (n) | 13.7 (315) | 14.3 (273) | 14.2 (381) | 14.5 (365) |
| Presumed cardiac cause, %* (n) | 97.9 (2242) | 98.0 (1864) | 97.9 (2616) | 97.6 (2462) |
| Service level of first vehicle to arrive | ||||
| BLS, %* (n) | 3.2 (74) | 74.1 (77) | 0.6 (16) | 0.1 (2) |
| BLS-D, %* (n) | 38.7 (886) | 39.9 (758) | 65.5 (1751) | 66.1 (1667) |
| BLS+, %* (n) | 15.6 (357) | 15.9 (302) | 11.0 (295) | 11.4 (288) |
| ALS, %* (n) | 42.5 (973) | 40.2 (765) | 22.9 (611) | 22.4 (566) |
| Peri-shock pause (seconds), mean (sd) | 30.6 (16.7) | 31.7 (15.9) | 21.7 (12.4) | 22.0 (12.8) |
| EMS initial rhythm | ||||
| VF, %* (n) | 26.0 (594) | 25.6 (484) | 23.3 (617) | 25.1 (627) |
| PEA, %* (n) | 19.1 (437) | 18.8 (355) | 19.5 (516) | 19.0 (474) |
| Asystole, %* (n) | 46.8 (1069) | 48.0 (908) | 46.4 (1226) | 45.3 (1131) |
| Perfusing, %* (n) | 0.1 (3) | 0.3 (5) | 0.1 (2) | 0.3 (7) |
| No shock and no strip, %* (n) | 8.0 (182) | 7.4 (140) | 10.7 (284) | 10.4 (259) |
EMS interval is the time from call receipt by emergency dispatch center to the time EMS arrives at the scene of the arrest. Baseline survival is for bystander-witnessed VF not attributed to an obvious non-cardiac cause. Basic life support is abbreviated BLS. Advanced life support is abbreviated ALS. Basic life support defibrillation is abbreviated BLS-D. BLS-D providers are equipped with defibrillation capability (AEDs). BLS+ are BLS providers with limited ALS scope of practice. For example, some BLS+ providers can place an intravenous access or supraglottic airways. Pulseless electrical activity is abbreviated PEA. Perfusing rhythm patients were noted to have a pulse upon the first EMS rhythm analysis.
% of known