Eur J Anaesthesiol 2014; 31:437–444
CORRESPONDENCE Influence of neuromuscular block and reversal on bispectral index and NeuroSense values Basile Christ, Philippe Guerci, Ce´dric Baumann, Claude Meistelman and Denis Schmartz From the CHU de Nancy, Hoˆpital Brabois adultes, Anesthe´sie-Re´animation (BC, PG, CM, DS), and CHU de Nancy, Service d’Epide´miologie et Evaluation Cliniques (CB), Vandoeuvres-le`s-Nancy, France Correspondance to Dr Basile Christ, De´partement d’anesthe´sie, CHU de Nancy, Hoˆpitaux de Brabois, rue du Morvan, Vandoeuvres-le`s-Nancy, 54511, France E-mail: [email protected] Published online 17 July 2013
This article is accompanied by the following Invited Commentary: Fuchs-Buder T. Residual neuromuscular blockade and postoperative pulmonary outcome. The missing piece of the puzzle. Eur J Anaesthesiol 2014; 31:401– 403. Editor, Monitors of depth of anaesthesia, based on electroencephalographic (EEG) analysis, are now widely used for common surgical procedures. However, several studies have demonstrated that the reliability of these monitors, for instance, bispectral index (BIS) or entropy, may be affected by neuromuscular blockade (NMB).1 The electromyographic (EMG) activity arising from the forehead muscles may disturb the EEG signal, resulting in a false value of BIS especially during ‘light’ anaesthesia.2 Actually, the EMG activity produces artefact signals that occur within the frequency ‘range of interest’ of the BIS (EMG30–300 Hz overlaps EEG0–50 Hz). The NeuroSense (NS-701; NeuroWave Systems Inc., Ohio, USA) is a new frontal EEG neuromonitor, which utilises wavelet analysis (WAVCNS) of the normalised EEG signal in the gamma frequency band (EEG40–60 Hz). It employs a deterministic algorithm, which yields a delay-free, linear and time-invariant quantifier of cortical activity.3 Little is known about the influence of NMB on the NeuroSense monitor. We investigated the influence of rocuronium-induced neuromuscular blockade as well as sugammadex reversal on BIS and NeuroSense values in patients scheduled for elective surgery. Ethical approval for this study was provided by the Ethics Committee of Nancy University Hospitals (CPP NANCY
EST III), Nancy, France, (Chairperson Dr P. Peton), on 19 May 2011. Patients suffering from moderate to severe renal failure, hepatic dysfunction, patients with neuromuscular disease, BMI less than 18.5 and more than 40 kg m-2 and patients allergic to rocuronium or sugammadex were excluded. Twenty-seven patients, scheduled for a wide range of different elective surgeries (resection of liver metastasis, thyroidectomy, colectomy, inguinal hernia repair, parathyroidectomy, rectovesical fistula, rectal prolapse, closure of colostomy, rectal villous tumour, insulinoma, laparoscopic cholecystectomy, partial pancreatectomy, popliteal aneurysm repair) were included in this observational study. The neuromonitors were a BIS Aspect A2000 version 3.31 and a NeuroSense model 701 version 1.12.0. A modified forehead sensor was designed for collecting both BIS and NeuroSense signals with the same electrodes while respecting the manufacturers’ instructions. A classical NeuroSense sensor was connected to classical BIS forehead sensors ensuring that both monitors see the same EEG waveform. The NeuroSense signal being bilateral, only the values monitored on the same side as the BIS have been taken into account. Impedance was verified to be at a low level and crosstalk between the two monitors was avoided by disabling continuous impedance check. After calibration, neuromuscular function was assessed by train of four (TOF) monitoring (TOF Watch SX; Schering-Plough/MSD, Levallois Perret, France). All patients were anaesthetised by target-controlled infusions of propofol and remifentanil with effect-site concentration adjusted according to the models by Schnider et al.4 and Minto et al.,5 respectively. Propofol concentration was adjusted to keep BIS values between 40 and 60, and remifentanil concentration was adjusted according to noxious stimulation. The predicted propofol and remifentanil concentrations were consistent with the concentrations published by Bouillon et al.6 After loss of consciousness and a 5-minute stabilisation period, BIS and NeuroSense values were recorded just before and 5 min after onset of 0.6 mg kgS1 rocuronium-induced neuromuscular blockade. If BIS or NeuroSense values were not completely stable (2), an average of three values over 10 s was performed. Throughout surgery, neuromuscular blockade was kept stable at 1 to 2 TOF responses by frequent intermittent bolus doses (0.07 mg kgS1) of rocuronium according to the judgement of the attending anaesthetist. At the end of the procedure, and the reappearance of two responses at the train of four, neuromuscular blockade was antagonised
0265-0215 ß 2014 Copyright European Society of Anaesthesiology
Copyright © European Society of Anaesthesiology. Unauthorized reproduction of this article is prohibited.
438 Correspondence
Table 1
Results before and after neuromuscular blockade
Ce propofol (mg ml 1) Ce remifentanil (ng ml 1) BIS NeuroSense
Before
After
P
2.4 0.5 2.0 0.0 60.1 6.8 61.4 8.8
2.4 0.5 2.0 0.0 51.7 8.9 53.9 7.4
0.2 mg l 1); quetiapine and duloxetine were both present in high therapeutic concentrations. Her conscious status remained depressed, probably due to the long half-life and high concentration of flurazepam. However, after 3 days, she deteriorated further and developed fever, more rigidity, hypertension and her serum creatine kinase levels increased from 221 to
Eur J Anaesthesiol 2014; 31:437–444 Copyright © European Society of Anaesthesiology. Unauthorized reproduction of this article is prohibited.
442 Correspondence
709 m l 1 (reference
CORRESPONDENCE Influence of neuromuscular block and reversal on bispectral index and NeuroSense values Basile Christ, Philippe Guerci, Ce´dric Baumann, Claude Meistelman and Denis Schmartz From the CHU de Nancy, Hoˆpital Brabois adultes, Anesthe´sie-Re´animation (BC, PG, CM, DS), and CHU de Nancy, Service d’Epide´miologie et Evaluation Cliniques (CB), Vandoeuvres-le`s-Nancy, France Correspondance to Dr Basile Christ, De´partement d’anesthe´sie, CHU de Nancy, Hoˆpitaux de Brabois, rue du Morvan, Vandoeuvres-le`s-Nancy, 54511, France E-mail: [email protected] Published online 17 July 2013
This article is accompanied by the following Invited Commentary: Fuchs-Buder T. Residual neuromuscular blockade and postoperative pulmonary outcome. The missing piece of the puzzle. Eur J Anaesthesiol 2014; 31:401– 403. Editor, Monitors of depth of anaesthesia, based on electroencephalographic (EEG) analysis, are now widely used for common surgical procedures. However, several studies have demonstrated that the reliability of these monitors, for instance, bispectral index (BIS) or entropy, may be affected by neuromuscular blockade (NMB).1 The electromyographic (EMG) activity arising from the forehead muscles may disturb the EEG signal, resulting in a false value of BIS especially during ‘light’ anaesthesia.2 Actually, the EMG activity produces artefact signals that occur within the frequency ‘range of interest’ of the BIS (EMG30–300 Hz overlaps EEG0–50 Hz). The NeuroSense (NS-701; NeuroWave Systems Inc., Ohio, USA) is a new frontal EEG neuromonitor, which utilises wavelet analysis (WAVCNS) of the normalised EEG signal in the gamma frequency band (EEG40–60 Hz). It employs a deterministic algorithm, which yields a delay-free, linear and time-invariant quantifier of cortical activity.3 Little is known about the influence of NMB on the NeuroSense monitor. We investigated the influence of rocuronium-induced neuromuscular blockade as well as sugammadex reversal on BIS and NeuroSense values in patients scheduled for elective surgery. Ethical approval for this study was provided by the Ethics Committee of Nancy University Hospitals (CPP NANCY
EST III), Nancy, France, (Chairperson Dr P. Peton), on 19 May 2011. Patients suffering from moderate to severe renal failure, hepatic dysfunction, patients with neuromuscular disease, BMI less than 18.5 and more than 40 kg m-2 and patients allergic to rocuronium or sugammadex were excluded. Twenty-seven patients, scheduled for a wide range of different elective surgeries (resection of liver metastasis, thyroidectomy, colectomy, inguinal hernia repair, parathyroidectomy, rectovesical fistula, rectal prolapse, closure of colostomy, rectal villous tumour, insulinoma, laparoscopic cholecystectomy, partial pancreatectomy, popliteal aneurysm repair) were included in this observational study. The neuromonitors were a BIS Aspect A2000 version 3.31 and a NeuroSense model 701 version 1.12.0. A modified forehead sensor was designed for collecting both BIS and NeuroSense signals with the same electrodes while respecting the manufacturers’ instructions. A classical NeuroSense sensor was connected to classical BIS forehead sensors ensuring that both monitors see the same EEG waveform. The NeuroSense signal being bilateral, only the values monitored on the same side as the BIS have been taken into account. Impedance was verified to be at a low level and crosstalk between the two monitors was avoided by disabling continuous impedance check. After calibration, neuromuscular function was assessed by train of four (TOF) monitoring (TOF Watch SX; Schering-Plough/MSD, Levallois Perret, France). All patients were anaesthetised by target-controlled infusions of propofol and remifentanil with effect-site concentration adjusted according to the models by Schnider et al.4 and Minto et al.,5 respectively. Propofol concentration was adjusted to keep BIS values between 40 and 60, and remifentanil concentration was adjusted according to noxious stimulation. The predicted propofol and remifentanil concentrations were consistent with the concentrations published by Bouillon et al.6 After loss of consciousness and a 5-minute stabilisation period, BIS and NeuroSense values were recorded just before and 5 min after onset of 0.6 mg kgS1 rocuronium-induced neuromuscular blockade. If BIS or NeuroSense values were not completely stable (2), an average of three values over 10 s was performed. Throughout surgery, neuromuscular blockade was kept stable at 1 to 2 TOF responses by frequent intermittent bolus doses (0.07 mg kgS1) of rocuronium according to the judgement of the attending anaesthetist. At the end of the procedure, and the reappearance of two responses at the train of four, neuromuscular blockade was antagonised
0265-0215 ß 2014 Copyright European Society of Anaesthesiology
Copyright © European Society of Anaesthesiology. Unauthorized reproduction of this article is prohibited.
438 Correspondence
Table 1
Results before and after neuromuscular blockade
Ce propofol (mg ml 1) Ce remifentanil (ng ml 1) BIS NeuroSense
Before
After
P
2.4 0.5 2.0 0.0 60.1 6.8 61.4 8.8
2.4 0.5 2.0 0.0 51.7 8.9 53.9 7.4
0.2 mg l 1); quetiapine and duloxetine were both present in high therapeutic concentrations. Her conscious status remained depressed, probably due to the long half-life and high concentration of flurazepam. However, after 3 days, she deteriorated further and developed fever, more rigidity, hypertension and her serum creatine kinase levels increased from 221 to
Eur J Anaesthesiol 2014; 31:437–444 Copyright © European Society of Anaesthesiology. Unauthorized reproduction of this article is prohibited.
442 Correspondence
709 m l 1 (reference
