The response of bispectral index to laryngoscopy, comparison between hemispheres in patients with a brain tumour versus a healthy control group

Background and Goal of Study: Electroencephalogram during anaesthesia may be affected by brain tumour.(1) We studied whether patients with a brain tumour have different BIS responses after laryngoscopy (LAR). We compared tumour patients with healthy control patients. Materials and Methods: After EC approval, 40 ASA 1 or 2 patients (control) and 41 intracranial tumour patients(tumour) received standardized anaesthesia while measuring bilateral BIS (BIS VISTAXP4 with bilateral sensor).(Covidien, Dublin, Ireland) Remifentanil was randomized to 3 or 5ng/ml effect‐site concentration (Minto) and maintained throughout the study. Propofol effect‐site concentration(CePROP)(Schnider) was set at 2 μg/ml and increased with incremental steps of 0.5 μg/ml until loss of consciousness was observed. After 3 minutes, laryngoscopy was performed and BIS was monitored during one minute. The median BIS of 1 minute before LAR is subtracted from the median BIS one minute after LAR to obtain delta BIS for each hemisphere. We tested if delta BIS is significantly different between hemispheres in control, between healthy and diseased hemispheres in tumour and between ipsilateral control and tumour hemispheres. Statistical significance was set at p< 0.05. Results and Discussion: No demographic differences were present except for age.(table 1) Delta BIS is not statistically different, neither between hemispheres in control, nor between healthy and diseased hemispheres in tumour groups.(table 2) No significant difference was found in delta BIS between ipsilateral control and pathological hemispheres. Conclusion(s): Bilateral BIS does not provide additional information on responsiveness to a standardized stimulus. We could not observe major differences in bilateral BIS response between control and brain tumour patients. Unilateral BIS monitoring seems to be equally informative in healthy and brain tumour patients compared to bilateral monitoring

Effects of propofol and sevoflurane on hepatic blood flow : a randomized controlled trial

Background Maintaining adequate perioperative hepatic blood flow (HBF) supply is essential for preservation of postoperative normal liver function. Propofol and sevoflurane affect arterial and portal HBF. Previous studies have suggested that propofol increases total HBF, primarily by increasing portal HBF, while sevoflurane has only minimal effect on total HBF. Primary objective was to compare the effect of propofol (group P) and sevoflurane (group S) on arterial, portal and total HBF and on the caval and portal vein pressure during major abdominal surgery. The study was performed in patients undergoing pancreaticoduodenectomy because - in contrast to hepatic surgical procedures - this is a standardized surgical procedure without potential anticipated severe hemodynamic disturbances, and it allows direct access to the hepatic blood vessels. Methods Patients were randomized according to the type of anesthetic drug used. For both groups, Bispectral Index (BIS) monitoring was used to monitor depth of anesthesia. All patients received goal-directed hemodynamic therapy (GDHT) guided by the transpulmonary thermodilution technique. Hemodynamic data were measured, recorded and guided by Pulsioflex (TM). Arterial, portal and total HBF were measured directly, using ultrasound transit time flow measurements (TTFM) and were related to hemodynamic variables. Results Eighteen patients were included. There was no significant difference between groups in arterial, portal and total HBF. As a result of the GDHT, pre-set hemodynamic targets were obtained in both groups, but MAP was significantly lower in group S (p = 0.01). In order to obtain these pre-set hemodynamic targets, group S necessitated a significantly higher need for vasopressor support (p < 0.01). Conclusion Hepatic blood flow was similar under a propofol-based and a sevoflurane-based anesthetic regimen. Related to the application of GDHT, pre-set hemodynamic goals were maintained in both groups, but sevoflurane-anaesthetized patients had a significantly higher need for vasopressor support

Intraoperative transfusion practices in Europe

Background: Transfusion of allogeneic blood influences outcome after surgery. Despite widespread availability of transfusion guidelines, transfusion practices might vary among physicians, departments, hospitals and countries. Our aim was to determine the amount of packed red blood cells (pRBC) and blood products transfused intraoperatively, and to describe factors determining transfusion throughout Europe. Methods: We did a prospective observational cohort study enrolling 5803 patients in 126 European centres that received at least one pRBC unit intraoperatively, during a continuous three month period in 2013. Results: The overall intraoperative transfusion rate was 1.8%; 59% of transfusions were at least partially initiated as a result of a physiological transfusion trigger-mostly because of hypotension (55.4%) and/or tachycardia (30.7%). Haemoglobin (Hb)-based transfusion trigger alone initiated only 8.5% of transfusions. The Hb concentration [mean (SD)] just before transfusion was 8.1 (1.7) g dl(-1) and increased to 9.8 (1.8) g dl(-1) after transfusion. The mean number of intraoperatively transfused pRBC units was 2.5 (2.7) units (median 2). Conclusions: Although European Society of Anaesthesiology transfusion guidelines are moderately implemented in Europe with respect to Hb threshold for transfusion (7-9 g dl(-1)), there is still an urgent need for further educational efforts that focus on the number of pRBC units to be transfused at this threshold

Intraoperative ventilator settings and their association with postoperative pulmonary complications in neurosurgical patients : post-hoc analysis of LAS VEGAS study

Background Limited information is available regarding intraoperative ventilator settings and the incidence of postoperative pulmonary complications (PPCs) in patients undergoing neurosurgical procedures. The aim of this post-hoc analysis of the 'Multicentre Local ASsessment of VEntilatory management during General Anaesthesia for Surgery' (LAS VEGAS) study was to examine the ventilator settings of patients undergoing neurosurgical procedures, and to explore the association between perioperative variables and the development of PPCs in neurosurgical patients. Methods Post-hoc analysis of LAS VEGAS study, restricted to patients undergoing neurosurgery. Patients were stratified into groups based on the type of surgery (brain and spine), the occurrence of PPCs and the assess respiratory risk in surgical patients in Catalonia (ARISCAT) score risk for PPCs. Results Seven hundred eighty-four patients were included in the analysis; 408 patients (52%) underwent spine surgery and 376 patients (48%) brain surgery. Median tidal volume (V-T) was 8 ml [Interquartile Range, IQR = 7.3-9] per predicted body weight; median positive end-expiratory pressure (PEEP) was 5 [3 to 5] cmH(2)0. Planned recruitment manoeuvres were used in the 6.9% of patients. No differences in ventilator settings were found among the sub-groups. PPCs occurred in 81 patients (10.3%). Duration of anaesthesia (odds ratio, 1.295 [95% confidence interval 1.067 to 1.572]; p = 0.009) and higher age for the brain group (odds ratio, 0.000 [0.000 to 0.189]; p = 0.031), but not intraoperative ventilator settings were independently associated with development of PPCs. Conclusions Neurosurgical patients are ventilated with low V-T and low PEEP, while recruitment manoeuvres are seldom applied. Intraoperative ventilator settings are not associated with PPCs

Sex difference and intra-operative tidal volume: Insights from the LAS VEGAS study

BACKGROUND: One key element of lung-protective ventilation is the use of a low tidal volume (VT). A sex difference in use of low tidal volume ventilation (LTVV) has been described in critically ill ICU patients.OBJECTIVES: The aim of this study was to determine whether a sex difference in use of LTVV also exists in operating room patients, and if present what factors drive this difference.DESIGN, PATIENTS AND SETTING: This is a posthoc analysis of LAS VEGAS, a 1-week worldwide observational study in adults requiring intra-operative ventilation during general anaesthesia for surgery in 146 hospitals in 29 countries.MAIN OUTCOME MEASURES: Women and men were compared with respect to use of LTVV, defined as VT of 8 ml kg-1 or less predicted bodyweight (PBW). A VT was deemed 'default' if the set VT was a round number. A mediation analysis assessed which factors may explain the sex difference in use of LTVV during intra-operative ventilation.RESULTS: This analysis includes 9864 patients, of whom 5425 (55%) were women. A default VT was often set, both in women and men; mode VT was 500 ml. Median [IQR] VT was higher in women than in men (8.6 [7.7 to 9.6] vs. 7.6 [6.8 to 8.4] ml kg-1 PBW, P &lt; 0.001). Compared with men, women were twice as likely not to receive LTVV [68.8 vs. 36.0%; relative risk ratio 2.1 (95% CI 1.9 to 2.1), P &lt; 0.001]. In the mediation analysis, patients' height and actual body weight (ABW) explained 81 and 18% of the sex difference in use of LTVV, respectively; it was not explained by the use of a default VT.CONCLUSION: In this worldwide cohort of patients receiving intra-operative ventilation during general anaesthesia for surgery, women received a higher VT than men during intra-operative ventilation. The risk for a female not to receive LTVV during surgery was double that of males. Height and ABW were the two mediators of the sex difference in use of LTVV.TRIAL REGISTRATION: The study was registered at Clinicaltrials.gov, NCT01601223