Table 1 Characteristics of included studies
Study | Population | The type of surgery | Intervention | Major outcome | Assessment scales | Conclusion |
|---|---|---|---|---|---|---|
EEG | ||||||
 Wildes 2019 [18] | 60 years or older | Major surgery (cardiac = 459; non-cardiac =754) | N = 1213 BIS-guided = 604 Routine care = 609 | POD (postoperative day1 -day5) | CAM/CAM-ICU | There was no difference between two groups. |
 Christopher 2020 [34] | 65 years or older | Major Noncardiac Surgery | N = 204 PSI- guided =102 Routine care =102 | POD (postoperative day 1–3) EEG suppression ratio | CAM | The incidence of delirium was not found to be different between two groups. |
 Radtke 2013 [30] | 60 years or older | Non-cardiac surgery | N = 1155 BIS-guided = 575 Routine care = 580 | POD (postoperative day 1–7, twice a day) POCD (postoperative 7 days and 3 months) | DSM IV CANTAB | The routine care group had a higher incidence of POD compared with the BIS-guided group. |
 Zhou 2018 [31] | 65–75 years old | Resection of colon carcinoma | N = 81 BIS-guided = 41 Routine care = 40 | POD (postoperative day 1 -day5) | CAM | The incidence of POD was significantly lower in the BIS-guided group compared with the routine care group. |
 Qian 2016 [32] | 65–85 years old | Gastrointestinal surgery | N = 180 BIS-guided = 90 Routine care = 90 | POD (postoperative day 1 -day7) | CAM | General anesthesia under BIS monitoring can reduce the incidence and duration of POD |
 Li 2014 [33] | 65–83 years old | Upper abdominal operation | N = 295 BIS-guided = 147 Routine care = 148 | POD (postoperative day 1 -day3) | DSM IV | The use of BIS guidance reduced the incidence of postoperative delirium |
 Whitlock 2014 [27] | 18 years or older | Cardiac or thoracic surgery | N = 310 BIS-guided = 149 ETAC-guided = 161 | POD (twice daily until postoperative day 10 or ICU discharge) | CAM-ICU | There was no difference between two groups. |
 Jidenstal 2012 [28] | 40–94 years old | ENT surgery | N = 32 AEP-guided = 16 Routine care = 16 | POD (postoperative day1) POCD (postoperative day 1 and 1 month) | CAM | AEP-guided anesthesia decreased the risk of early POCD rather than early POD. |
 Chan 2013 [29] | 60 years or older | Major non-cardiac surgery | N = 902 BIS-guided = 450 Routine care = 452 | POD (in-hospital) POCD (postoperative 1 week and 3 months) | CAM | BIS-guided anesthesia reduced the risk of postoperative delirium. |
 Jidenstal 2011 [26] | 18–92 years old | Ophthalmic surgery | N = 450 AEP-guided = 224 Routine care = 226 | POCD (postoperative 1 day, 1 week or 1 month) | MMT and CFQ) | Patients with AEP-guided anaesthesia had a lower risk of early postoperative cognitive decline. |
 Kunst 2020 [45] | 64 years or older | CABG | N = 82 BIS and rSO2- guided =42 Routine care =40 | POD (postoperative day 3–5) POCD (postoperative day 3–5, 6 weeks) | CAM MMSE | Optimizing both depth of anesthesia and rSO2 in elderly patients undergoing cardiac surgery resulted in a significant reduction in the postoperative delirium. |
 Ballard 2012 [44] | 70 years or older | Abdominal and Orthopaedic surgery | N = 72 BIS and rSO2- guided =34 Routine care = 38 | POCD (postoperative 1 week, 12 weeks, 52 weeks) | MMSE | Intraoperative monitoring of anaesthetic depth and cerebral oxygenation can reduce post-operative cognitive impairment. |
Cerebral Oxygenation Monitoring | ||||||
 Casati 2005 [35] | 65 years or older | Major abdominal surgery | N = 122 rSO2- guided =56 Routine care = 66 | POCD (postoperative 1 week) | MMSE | Using rSO2 monitoring seems to result in less cognitive decline. |
 Colak 2015 [36] | 40–80 years old | CABG | N = 190 rSO2- guided =94 Routine care = 96 | POCD (postoperative 1 week) POD (postoperative 1 week) | CTT and GP test | The use of INVOS monitoring has a predictive value in terms of lower incidence of early postoperative cognitive decline. |
 Kara 2015 [39] | – | CABG | N = 79 rSO2- guided =43 Routine care = 36 | POCD | MoCA | Intraoperative NIRS usage can decrease the incidence of POCD |
 Mohandas 2013 [40] | – | Open heart surgery | N = 100 rSO2- guided =50 Routine care = 50 | POCD (postoperative 1 week and 3 months) | MMSE, ASEM | Intraoperative monitoring of rSO2 can significantly decrease the incidence of postoperative neurocognitive decline. |
 Murniece 2019 [42] | 18 years or older | Spinal Neurosurgery | N = 34 rSO2- guided =23 Routine care = 11 | POCD (postoperative 1 week and 3 months) | MoCA | Use of the NIRS-based clinical algorithm can help to avoid POCD in patients. |
 Slater 2009 [43] | – | CABG | N = 240 rSO2-guided = 125 Routine care = 115 | POCD (postoperative 1 week and 3 months) | MMSE, ASEM | There was no difference between two groups on POCD. |
 Deschamps 2016 [38] | 18 years or older | High-risk Cardiac Surgery | N = 201 rSO2- guided =102 Routine care = 99 | POD (postoperative 3 months) | DSM IV | There was no difference between two groups on POD. |
 Lei 2017 [41] | 60 years or older | Cardiac surgery | N = 249 rSO2- guided =123 Routine care = 126 | POD (postoperative 12 h-7 days) | CAM/CAM-ICU | Three was no difference in the incidence of POD between the intervention group and control group. |
 Uysal 2020 [19] | 18 years or older | Cardiac surgery | N = 125 rSO2- guided =59 Routine care = 66 | POD-ICU (postoperative 24 h, 3 and 6 months | Cognitive Stability Index HeadMinder | Three was no difference in the incidence of POD between the intervention group and control group. |
 Cox 2018 [37] | 18 and 85 years | Arthroscopic shoulder surgery | N = 40 rSO2- guided =20 Routine care = 20 | POCD (postoperatively, before discharge; postoperative 2 weeks and 6 weeks) | MoCA | No difference between two groups. |