Ty (including postoperative neurological complications) in elderly patients, compared to the younger one [31]. Furthermore, their survival increases significantly compared to restrictive treatment like subtotal resections and biopsies. MAC for AC was also used efficaciously in five elderly patients (>60 years), with complex co-morbidities [28]. Intraoperative hypoxia was reported for five patients [36,59], but all cases could be resolved with simple dose reduction and oxygen application. One large retrospective study (n = 611) used all possible combinations of propofol, remifentanil and dexmedetomidine in patients with significantly different baseline characteristics [34]. Only high-risk patients (high body-massindex (BMI), high tumour mass, high blood loss estimated) (n = 8) received a LMA for the initial procedure [34]. The total rate of AC failure in all studies using the MAC technique and reporting the failure rate was 81 of totally 3616 procedures. Excluding the duplicate study of Nossek et al. [42] and Grossman et al. [31] which contained partially the same patients like the AZD-8055 supplier larger second study [43], our meta-analysis calculated with the random effects model revealed a proportion of a 2 failure rate [95 CI: 1?] in 2700 procedures, which reported AC failure (Fig 2). AAA–Awake-awake-awake technique. Hansen et al. were the first, who reported the awake-awake-awake technique avoiding sedatives in 47 patients undergoing 50 AC procedures by using RSNBs, permanent presence of a contact person, and therapeutic communication [33]. Instead of using premedication with benzodiazepines, a strong pre-operative confidence with calming the patient was established during an extensive pre-operative personal visit of the attending anaesthesiologist. Subsequently the anaesthesiologist continuously guided the patients intraoperatively with strong rapport, physical contact and therapeutically communication. This included hypnotic positive suggestions like reframing disturbing surgery related noises and dissociation into a “safe place”. Only two-thirds of the patients requested remifentanil with an average total dose of 156g. Intraoperative vigilance tests showed equal or higherPLOS ONE | DOI:10.1371/journal.pone.0156448 May 26,29 /Anaesthesia Management for Awake Craniotomyscores than preoperative tests. In the postoperative interview conducted in twenty-two patients, 73 of patients reported a lack of any discomfort, 95 felt “adequate prepared”, and 82 did not experience any fear at all. BIS monitoring was applied in all patients. The AC failure rate was minimal with one patient out of 50 AC procedures. This patient experienced general seizure, which could not be handled only with cold saline solution or minimal doses of propofol, but the surgery was smoothly continued in GA. A meta-analysis could not be performed for the AAA technique due to only one study reporting it. Adverse events. A purchase Rocaglamide reasonable meta-analysis and logistic meta-regression could only be performed for four outcome variables: AC failures, seizures, conversion into general anaesthesia and new postoperative neurologic dysfunction based on the anaesthetic approach of MAC or SAS. The other variables were not reported frequently enough in the included studies for both kinds of anaesthesia technique. Mortality was reported in thirty-eight studies, but not included in the meta-analysis as a single outcome variable due to the extremely rare event rate. It was integrated in the composite o.Ty (including postoperative neurological complications) in elderly patients, compared to the younger one [31]. Furthermore, their survival increases significantly compared to restrictive treatment like subtotal resections and biopsies. MAC for AC was also used efficaciously in five elderly patients (>60 years), with complex co-morbidities [28]. Intraoperative hypoxia was reported for five patients [36,59], but all cases could be resolved with simple dose reduction and oxygen application. One large retrospective study (n = 611) used all possible combinations of propofol, remifentanil and dexmedetomidine in patients with significantly different baseline characteristics [34]. Only high-risk patients (high body-massindex (BMI), high tumour mass, high blood loss estimated) (n = 8) received a LMA for the initial procedure [34]. The total rate of AC failure in all studies using the MAC technique and reporting the failure rate was 81 of totally 3616 procedures. Excluding the duplicate study of Nossek et al. [42] and Grossman et al. [31] which contained partially the same patients like the larger second study [43], our meta-analysis calculated with the random effects model revealed a proportion of a 2 failure rate [95 CI: 1?] in 2700 procedures, which reported AC failure (Fig 2). AAA–Awake-awake-awake technique. Hansen et al. were the first, who reported the awake-awake-awake technique avoiding sedatives in 47 patients undergoing 50 AC procedures by using RSNBs, permanent presence of a contact person, and therapeutic communication [33]. Instead of using premedication with benzodiazepines, a strong pre-operative confidence with calming the patient was established during an extensive pre-operative personal visit of the attending anaesthesiologist. Subsequently the anaesthesiologist continuously guided the patients intraoperatively with strong rapport, physical contact and therapeutically communication. This included hypnotic positive suggestions like reframing disturbing surgery related noises and dissociation into a “safe place”. Only two-thirds of the patients requested remifentanil with an average total dose of 156g. Intraoperative vigilance tests showed equal or higherPLOS ONE | DOI:10.1371/journal.pone.0156448 May 26,29 /Anaesthesia Management for Awake Craniotomyscores than preoperative tests. In the postoperative interview conducted in twenty-two patients, 73 of patients reported a lack of any discomfort, 95 felt “adequate prepared”, and 82 did not experience any fear at all. BIS monitoring was applied in all patients. The AC failure rate was minimal with one patient out of 50 AC procedures. This patient experienced general seizure, which could not be handled only with cold saline solution or minimal doses of propofol, but the surgery was smoothly continued in GA. A meta-analysis could not be performed for the AAA technique due to only one study reporting it. Adverse events. A reasonable meta-analysis and logistic meta-regression could only be performed for four outcome variables: AC failures, seizures, conversion into general anaesthesia and new postoperative neurologic dysfunction based on the anaesthetic approach of MAC or SAS. The other variables were not reported frequently enough in the included studies for both kinds of anaesthesia technique. Mortality was reported in thirty-eight studies, but not included in the meta-analysis as a single outcome variable due to the extremely rare event rate. It was integrated in the composite o.