Table 1. Baseline characteristics of included studies and patients.
| First author's surname | Study design | Country | Sample size | Mean age (years) | Percentage male (%) | Number of IH/OH | Assessment of exposure | Duration of resuscitation (minutes) | Reported outcomes | Study quality |
|---|---|---|---|---|---|---|---|---|---|---|
| Ahn 2013 [25] | Prospective | USA | 50 | 64.8 | 72.0 | 36/14 | Equanox 7600, Nonin Medical, Inc., Plymouth, MN, USA | 34.4 | Initial rSO2%; mean rSO2% | 7 |
| Parnia 2014 [26] | Retrospective | USA | 34 | 71.0 | 64.7 | 34/0 | Equanox, Nonin, Plymouth, MI, USA INVOS, Covidien, Mansfield, MA, USA | 19.0 | Mean rSO2% | 6 |
| Genbrugge 2015 [27] | Prospective | Belgium | 49 | 73.0 | 63.3 | 0/49 | Equanox Advance, Nonin Medical, Inc., Plymouth, MN, USA | 21.0 | Initial rSO2%; mean rSO2% | 7 |
| Singer 2014 [28] | Retrospective | USA | 59 | 68.7 | 84.7 | 0/59 | Equanox, Nonin, Plymouth MI, USA | NA | Mean rSO2% | 6 |
| Fukuda 2014 [29] | Prospective | Japan | 69 | 66.1 | 69.6 | 0/69 | INVOS 5100, Covidien, Boulder, CO, USA | 38.7 | Initial rSO2% | 7 |
| Koyama 2013 [30] | Prospective | Japan | 15 | 79.5 | 66.7 | 0/15 | Hamamatsu Photonics, Hamamatsu-Shi, Shizuoka, Japan | NA | Initial rSO2% | 6 |
| Parnia 2012 [31] | Retrospective | USA | 15 | 73.8 | NA | 15/0 | INVOS Somanetics, Troy, USA | 16.3 | Mean rSO2% | 5 |
| Meex 2013 [32] | Prospective | Belgium | 14 | 66.0 | 74.4 | 5/9 | FORE-SIGHT (CAS Medical Systems, Branford, CT, USA) and Equanox Advance (Nonin Medical, Inc., Plymouth, MN, USA) | 25.0 | Initial rSO2% | 6 |
| Schewe 2014 [33] | Prospective | Germany | 10 | 73.0 | 80.0 | 0/10 | Equanox 7600, Nonin Medical, Inc., Plymouth, MN, USA | NA | Mean rSO2% | 5 |
| Ibrahim 2015 [34] | Prospective | USA | 27 | 65.6 | 96.3 | 27/0 | Invos 5100 C near infrared spectroscopy device (Invos Somanetics, Troy, USA) | 20.8 | Initial rSO2%; mean rSO2% | 7 |
| Parnia 2016 [35] | Prospective | USA and United Kingdom | 183 | 68.6 | 60.7 | 183/0 | Equanox 7600, Nonin Medical, Plymouth, MN, USA | 28.7 | Mean rSO2% | 7 |
| Prosen 2018 [36] | Prospective | Slovenia | 53 | 68.5 | 84.9 | 0/53 | INVOS oximeter (Somanetics Corporation, Troy, MI, USA) | 16.2 | Initial rSO2%; mean rSO2% | 7 |
| Singer 2018 [37] | Prospective | USA | 100 | 69.0 | 73.0 | 0/100 | Equanox 7600, Nonin Medical, Plymouth, MN, USA | NA | Mean rSO2% | 7 |
*IH: in-hospital arrests; NA: not available; OH: out-of-hospital arrests; rSO2: regional cerebral oxygen saturation.