Be performed in an operating room and describe the anaesthetic approach used for AC. Additionally, they had to report data for at least one of the following outcome variables: intraoperative seizures, hypoxia and arterial hypertension, intra-/ postoperative nausea and vomiting (PONV), new postoperative neurological dysfunction, conversion to GA and failure of AC. Of note, only studies reporting on adult patients (18 years of age) were initially considered. It became apparent, that some studies, even with the applied children excluding filter in our search strategy, also reported on AC procedures in several children. Despite this, the mean age in these studies corresponded to adults and after discussion with all authors we decided not to exclude these studies, as they were not real solely paediatric studies. Types of intervention: We included studies, which reported on one of the following three anaesthetic approaches: Asleep-awake-asleep (SAS) technique, monitored anaesthesia care (MAC), and the U0126 web awake-awake-awake (AAA) technique.Information sourcesA PubMed and EMBASE database search was carried out for the time frame from 01.01.2007 until 31.12.2015. The search and screening process were independently carried out by MC and AS. Additionally the reference lists of the included articles were scanned for further eligible studies. One author was contacted, to provide additional study information [10].Systematic searchEMBASE and PubMed search strategy are shown in S1 File. Records identified through PubMed and EMBASE were hand-searched on basis of the title and abstract. Resulting records were then hand-searched on basis of the full text and records not matching the topic of this SRPLOS ONE | DOI:10.1371/journal.pone.0156448 May 26,3 /Anaesthesia Management for Awake Craniotomywere excluded. Of note, articles reporting studies conducted outside the operating room, like in a MRI suite, or with the use of an intraoperative MRI guidance were excluded. Study selection and data collection. MC and AS screened the titles independently and removed articles that did not meet the pre-specified screening criteria, or were duplicate articles. The remaining articles were screened on the basis of their abstract. All apparently eligible articles were analysed in detail, according to a pre-piloted form, by their full text. Any uncertainties were discussed between the two primary review authors. In the event of persistent disagreement, all other authors were integrated in the discussion until consensus was achieved. Articles were also double checked for not apparently study-duplicates, in regard to juxtaposed author names, treatment comparisons, sample sizes, and outcomes. It was planned to contact the authors, if important outcome parameter are missing, and the study met our inclusion criteria. Data items. AS and MC extracted the following data from each included study: 1.) Study characteristics (study design, recruitment period, sample size, comparative group, endpoint/ aim of the study, study conclusion). 2.) Anaesthesia characteristics (kind of technique, drugs and dosages, patient airway). 3.) Patient characteristics (gender, age and kind of tumour). 4.) Intraoperative characteristics and adverse events (surgery durations, AC failures, conversion to GA, hypoxia, arterial hypertension and seizures). An AC failure was not only considered if conversion to GA was required, but also if U0126 site adequate awake brain mapping/ monitoring could not have been achieved due.Be performed in an operating room and describe the anaesthetic approach used for AC. Additionally, they had to report data for at least one of the following outcome variables: intraoperative seizures, hypoxia and arterial hypertension, intra-/ postoperative nausea and vomiting (PONV), new postoperative neurological dysfunction, conversion to GA and failure of AC. Of note, only studies reporting on adult patients (18 years of age) were initially considered. It became apparent, that some studies, even with the applied children excluding filter in our search strategy, also reported on AC procedures in several children. Despite this, the mean age in these studies corresponded to adults and after discussion with all authors we decided not to exclude these studies, as they were not real solely paediatric studies. Types of intervention: We included studies, which reported on one of the following three anaesthetic approaches: Asleep-awake-asleep (SAS) technique, monitored anaesthesia care (MAC), and the awake-awake-awake (AAA) technique.Information sourcesA PubMed and EMBASE database search was carried out for the time frame from 01.01.2007 until 31.12.2015. The search and screening process were independently carried out by MC and AS. Additionally the reference lists of the included articles were scanned for further eligible studies. One author was contacted, to provide additional study information [10].Systematic searchEMBASE and PubMed search strategy are shown in S1 File. Records identified through PubMed and EMBASE were hand-searched on basis of the title and abstract. Resulting records were then hand-searched on basis of the full text and records not matching the topic of this SRPLOS ONE | DOI:10.1371/journal.pone.0156448 May 26,3 /Anaesthesia Management for Awake Craniotomywere excluded. Of note, articles reporting studies conducted outside the operating room, like in a MRI suite, or with the use of an intraoperative MRI guidance were excluded. Study selection and data collection. MC and AS screened the titles independently and removed articles that did not meet the pre-specified screening criteria, or were duplicate articles. The remaining articles were screened on the basis of their abstract. All apparently eligible articles were analysed in detail, according to a pre-piloted form, by their full text. Any uncertainties were discussed between the two primary review authors. In the event of persistent disagreement, all other authors were integrated in the discussion until consensus was achieved. Articles were also double checked for not apparently study-duplicates, in regard to juxtaposed author names, treatment comparisons, sample sizes, and outcomes. It was planned to contact the authors, if important outcome parameter are missing, and the study met our inclusion criteria. Data items. AS and MC extracted the following data from each included study: 1.) Study characteristics (study design, recruitment period, sample size, comparative group, endpoint/ aim of the study, study conclusion). 2.) Anaesthesia characteristics (kind of technique, drugs and dosages, patient airway). 3.) Patient characteristics (gender, age and kind of tumour). 4.) Intraoperative characteristics and adverse events (surgery durations, AC failures, conversion to GA, hypoxia, arterial hypertension and seizures). An AC failure was not only considered if conversion to GA was required, but also if adequate awake brain mapping/ monitoring could not have been achieved due.