Difficult airway management and low Bispectral Index (BIS) in a patient with left Bochdalek congenital diaphragmatic hernia (CDH).

BACKGROUND: Bochdalek congenital diaphragmatic hernia (CDH) is a developmental defect in the posterolateral diaphragm, allowing herniation of abdominal contents into the thorax causing mechanical compression of the developing lung parenchyma and lung hypoplasia. We describe a case of an adult patient with a Bochdalek hernia who underwent minimally invasive right thoracotomy Perceval bioprosthetic aortic valve replacement (AVR) requiring one-lung ventilation (OLV) on the side of the hernia. This is a complex and challenging case that brings up numerous thought-provoking anesthetic implications. To the best of our knowledge, a Pubmed search did not reveal any publication to date of difficult airway management in an adult patient with CDH. CASE PRESENTATION: The first major problem encountered was patient's crus habitus anatomical condition (exceedingly ventrally displaced trachea) Mallampati Class IV and Cormack-Lehane grade IV extremely difficult endotracheal intubation. Neither glottis nor epiglottis was visible on laryngoscopy; resulting in failed placement of the double-lumen endobronchial tube (DLT) following numerous attempts. The DLT was eventually placed via GlideScope videolaryngoscopy. Whereas the endobroncheal right lung block for left OLV was successfully placed using fiberopticscopy. The crus habitus encroached on OLV tidal volume by the cranially displaced ascending colon and left kidney. Anesthesia was maintained with remifentanil /sevoflurane; adjusted to maintain bispectral index (BIS) at 40-60. Digitally recorded BIS was 38-62 except when BIS precipitously declined to 14-38 (SR, suppression ratio < 10) for 25 min after termination of the cardiopulmonary bypass. CONCLUSIONS: We report a case essentially dealing with an anatomically distorted difficult airway in a patient with left Bochdalek CDH undergoing a complex AVR. We describe anesthetic difficulties and unforeseen issues encountered; such as an extremely difficult DLT placement.

Editorial: Optimizing opioid prescriptions in the emergency department.

Optimizing opioid prescriptions in the emergency department is essential to address the opioid pandemic while ensuring patient wellbeing. This requires a comprehensive approach that includes exploring alternatives to opioids for pain management, identifying individuals at risk for opioid addiction, implementing evidence-based guidelines, and involving doctors in the management of opioid addiction.

Migraine, interferon ß1a and siponimod immunomodulator therapies.

BACKGROUND: Autoimmunity seems to play a great role in the pathogenesis of migraine headache pain. There is far more evidence that interferon can exacerbate migraines. We report a case where remission of severe comorbid migraine attacks happened with the start of interferon ß1a (Merck, Netherlands) immunomodulation therapy. Therapy for multiple sclerosis was decided according to the severity of the debilitating comorbid migraine headache pain rather than the evolution of multiple sclerosis the far more serious disease. CASE PRESENTATION: A 63-years old patient suffered for 30-years from migraine headache of severe disability assessment scale (MIDAS) Grade-IV = 27. He also suffered for 25-years from optic-sensory relapsing remitting multiple sclerosis (RRMS). Subcutaneous interferon ß1a 44-µg immunomodulation therapy for 4-years resulted in multiple sclerosis complete remission. The start of interferon ß1a therapy for multiple sclerosis seemed to help resolving the comorbid migraine attacks. The visual aura premonitory symptom preceding migraine headache would end up with a feeling of post visual aura clearer field of vision and a feeling of wellbeing. As the patient developed secondary progressive multiple sclerosis (SPMS), oral siponimod 2 mg (Novartis, Ireland), currently the only available therapy for SPMS, replaced his interferon therapy. This was associated with a relapse of migraine severe attacks. Reverting back to interferon therapy was again associated with migraine headache remission. CONCLUSIONS: Interferon ß1a might be an efficic therapy for "autoimmune migraine". With numerous immunomodulators currently available for other systemic autoimmune diseases associated with comorbid migraine; examining the effect of these immunomodulatory therapies on comorbid migraine headache could be beneficial in finding a specific immunomodulator therapy for "autoimmune migraine".

Age progression from vicenarians (20-29 year) to nonagenarians (90-99 year) among a population pharmacokinetic/pharmacodynamic (PopPk-PD) covariate analysis of propofol-bispectral index (BIS) electroencephalography.

BACKGROUND: Pharmacokinetic/pharmacodynamic (PK/PD) modeling has made an enormous contribution to intravenous anesthesia. Because of their altered physiological, pharmacological and pathological aspects, titrating general anesthesia in the elderly is a challenging task. METHODS: Eighty patients were consecutively enrolled divided by decades from vicenarians (20-29 year) to nonagenarians (90-99 year) into eight groups. Using target controlled infusion (TCI) and electroencephalographic (EEG)-derived bispectral index (BIS) we set propofol plasma concentration (Cp) to gradually reach 3.5 µg mL-1 over 3.5-min. In each patient, we constructed a PK/PD model and conducted a population PK/PD (PopPK-PD) covariate analysis. RESULTS: Age was significant covariate for baseline BIS effect (E0), inhibitory propofol concentration at 50% BIS decline (IC50) and maximum BIS decline (Emax). First-order rate constant Ke0 of 0.47 min-1 in vicenarians (20-29 year) gradually increased with age-progression to 1.85 min-1 in nonagenarians (90-99 year). Simulation modelling showed that clinically recommended Cp of 3.5 µg mL-1 for 20-29 year BIS 50 should be reduced to 3.0 for 30-49 year, 2.5 for 50-69 year and 2.0 for 80-89 year. CONCLUSION: We quantified and graded EEG-BIS age-progression among different age groups divided by decades. We demonstrated deeper BIS values with decades' age progression. Our data has important implications for propofol dosing. The practical information for physicians in their daily clinical practice is using propofol Cp of 3.5 µg mL-1 might not yield BIS value of 50 in elderly patients. Our simulations showed that the recommended regimen of Cp 3.5 µg mL-1 for 20-29 year should be gradually decreased to 2.0 µg mL-1 for 80-89 year. CLINICAL TRIAL REGISTRY NUMBERS: European Community Clinical Trials Database EudraCT (http://eudract.emea.eu) initial trial registration number: 2011-002847-81, and subsequently registered at www.clinicaltrials.gov; trial registration number: NCT02585284. Xijing Hospital of Fourth Military Medical University ethics committee approval number 20110707-4.

Correction to: Mindray 3-directional NMT Module (a new generation "Tri-axial" neuromuscular monitor) versus the Relaxometer mechanomyograph and versus the TOF-Watch SX acceleromyograph.

In the original publication of the article, the article note "Ashraf A. Dahaba and Zhao Yang Xiao equally contributed to the study and are both first authors." was published incorrectly. The correct statement should read as "Ashraf A. Dahaba and Zhao Yang Xiao equally contributed to the study and are both first authors and are both co-corresponding authors."

Mindray 3-directional NMT Module (a new generation "Tri-axial" neuromuscular monitor) versus the Relaxometer mechanomyograph and versus the TOF-Watch SX acceleromyograph.

Recently introduced Mindray "3-directional" neuromuscular transmission transducer (NMT, Shenzhen, China) acceleromyograph) claim to monitor thumb movement in 3 different directions. We compared NMT with the gold standard Relaxometer® mechanomyograph (MMG, Groningen University, Netherlands) in Study-1 and with TOF-Watch SX™ (WTCH) acceleromyograph from which it was developed in Study-2. We used first twitch (T1%) and train-of-four (TOF) ratio rocuronium 0.6 mg kg-1 neuromuscular block to evaluate NMT diagnostic accuracy in indicating 3 clinically relevant time points namely; MMG T1 5% (95% twitch depression) for tracheal intubation, MMG T1 25% for repeat neuromuscular blocking agents (NMBAs) administration, and MMG 0.9 TOF ratio full neuromuscular block recovery. We compared onset time (time from beginning of rocuronium administration until maximal depression), Dur25 (time until T1 25% recovery) and Dur0.9 (time until 0.9 TOF ratio recovery). In Study-1, NMT showed low sensitivity in indicating MMG time for tracheal intubation, repeat NMBAs administration and full neuromuscular block recovery (6.25%, 38.9% and 38.9% respectively). NMT onset time, Dur25 and Dur0.9 (2:51 ± 00:57, 36:50 ± 24:25, 70:08 ± 25:27 min:s) were significantly longer than MMG (1:56 ± 00:46, 30:26 ± 20:24, 62:03 ± 20:01). In Study-2, NMT onset time, Dur25 and Dur0.9 (02:37 ± 00:53, 35:38 ± 11:54, 53:40 ± 13:49) were not significantly different than WTCH (02:23 ± 00:45, 33:27 ± 12:51, 53:57 ± 12:47). NMT could not efficaciously detect MMG time for tracheal intubation; NMBAs repeat dose administration or full neuromuscular block recovery. Data from NMT cannot be used interchangeably with MMG. Our study revealed that NMT Tri-axial acceleromyography seems to offer no advantage over the MMG gold standard or the classic Mono-axial TOF-Watch SX monitor.

Advances in anesthesia technology are improving patient care, but many challenges remain.

Although significant advances in clinical monitoring technology and clinical practice development have taken place in the last several decades, in this editorial we argue that much more still needs to be done. We begin by identifying many of the improvements in perioperative technology that have become available in recent years; these include electroencephalographic depth of anesthesia monitoring, bedside ultrasonography, advanced neuromuscular transmission monitoring systems, and other developments. We then discuss some of the perioperative technical challenges that remain to be satisfactorily addressed, such as products that incorporate poor software design or offer a confusing user interface. Finally we suggest that the journal support initiatives to help remedy this problem by publishing reports on the evaluation of medical equipment as a means to restore the link between clinical research and clinical end-users.

Correction to: Advances in anesthesia technology are improving patient care, but many challenges remain.

Unfortunately, after publication of this article [1], it was noticed that the name of Ashraf A. Dahaba is incorrectly displayed as Ashraf Dahaba. The full, corrected author list can be seen here.

Different propofol-remifentanil or sevoflurane-remifentanil bispectral index levels for electrocorticographic spike identification during epilepsy surgery.

BACKGROUND: Medical therapy, the cornerstone of managing epilepsy, still fails a substantial portion of patients. Little information is available regarding the potential impact of different bispectral index (BIS) levels on electrocorticographic spike identification for surgical epileptic foci resection. METHODS: Twenty-two intractable epilepsy subjects were randomly allocated to the propofol-remifentanil or sevoflurane-remifentanil groups, and were further randomized to four BIS85 (BIS 71-85), BIS70 (BIS 56-70), BIS55 (BIS 41-55), and BIS40 (BIS ≤40) sequence order. RESULTS: Two-way ANOVA revealed no differences between groups in spike frequency (P = 0.720), spike amplitude (P = 0.647), or number of spiking leads (P = 0.653). In the propofol and sevoflurane groups, decreasing BIS levels increased mean ± SD spike/min frequency (P < 0.001 and P < 0.001) at BIS85 (10 ± 12 and 10 ± 8), BIS70 (19 ± 17 and 17 ± 15), BIS55 (22 ± 17 and 18 ± 8), and BIS40 (25 ± 15 and 23 ± 17). Furthermore, in the propofol and sevoflurane groups, decreasing BIS levels increased spike microvolt amplitude (P = 0.006 and P = 0.009) at BIS85 (1,100 ± 400 and 750 ± 400), BIS70 (1,200 ± 460 and 850 ± 490), BIS55 (1,300 ± 560 and 940 ± 700), and BIS40 (1,400 ± 570 and 1,300 ± 700). Whereas, in the propofol and sevoflurane groups, there was no difference in the location or number of spiking leads (P = 0.057 and P = 0.109) at the four BIS levels. Compared with BIS85, spike frequency in the propofol and sevoflurane groups increased 100 and 170% at BIS70, 116 and 180% at BIS55, and 132 and 230% at BIS40. Compared with BIS85, spike amplitude increased 108 and 113% at BIS70, 121 and 125% at BIS55, and 128 and 170% at BIS40. CONCLUSION: Decreasing BIS levels in the propofol and sevoflurane groups enhanced epileptogenic spike frequency and amplitude with the same location and number of spiking leads.

Mass casualties in Tahrir Square at the climax of the Egyptian uprising: evidence of an emerging pattern of regime's organized escalating violence during 10 hours on the night of January 28, 2011.

OBJECTIVE: Documentation of the management of mass casualties in Tahrir Square. BACKGROUND: We documented the sequences of our medical response to mass casualties in Tahrir Square between January 28, 2011, and February 4, 2011, at "Kasr El-Ainy" Cairo University Hospital, the largest hospital in the Middle East and the tertiary referral center for all hospitals in Egypt that happened to be the closest to Tahrir Square. METHODS: At the peak of Tahrir Square demonstrations, injured protesters received first aid in a makeshift clinic inside Tahrir Square, manned by volunteer doctors and nurses, before they were evacuated to the Cairo University Hospital Surgical Casualty Department. General surgeons, orthopedic surgeons, anesthesiologists, and critical care nurses from multidisciplinary teams hastily triaged and treated the incoming casualties. Thousands of casualties were seen at the peak of the uprising. This article provides a detailed review of mass casualties seen between January 28, 2011, and February 4, 2011. RESULTS: Of 3012 casualties, 453 were triaged as "immediate care" patients. On arrival, 339 of 453 patients (74.8%) needed surgical intervention within 6 hours of arrival whereas 74 of 453 patients (16.3%) were managed conservatively. Forty of 453 (8.8%) of patients did not survive their injuries. Most of the inpatients (302/453, 66.6%) were admitted within 10 hours on January 28, 2011, during which evidence of a pattern of regime's organized escalating violence emerged. CONCLUSIONS: We describe the pattern of injuries and our management of Tahrir Square mass casualties. We believe that forming multidisciplinary teams of surgeons, anesthesiologists, and nurses was the key to our effective management of such a huge event.

Location matters: Overlooked ethnic-geographic effect in China and Austria on propofol/cisatracurium sex differences among a population pharmacokinetic/pharmacodynamic (PopPK/PD) covariate analysis in men, women, and one transgender subject.

A quick literature search using "sex/gender" vs. the commonly used hypnotic propofol or neuromuscular-blocking agent cisatracurium will reveal numerous contradictory sex difference publications depending on the ethnic-geographic location of where these studies were conducted. We induced anesthesia with cisatracurium besylate (GlaxoSmithKline) 100 µg kg-1 administered exactly 1 minute following propofol (AstraZeneca) 2 mg kg-1 . In 20 male and 20 female ethnic Han-Chinese test set patients (Xi'an China), and in similar ethnic white Austrian validation set patients (Graz Austria), we quantified propofol/cisatracurium pharmacodynamic parameters namely propofol onset time, lag time, plasma concentrations (Cp ) at loss-of-behavioral response (LOBR) using bispectral index (BIS); cisatracurium onset time, lag time, and Cp at T1 % (first twitch of train-of-four) complete twitch suppression using mechanomyography (MMG). Serial arterial blood samples were collected for population pharmacokinetic (PopPK) analysis of all demographic and biological covariates (region, sex, age, weight, and height) versus volumes of distribution and clearances pharmacokinetic parameters. In Chinese women (but not in white women), propofol Cp at LOBR was 33.60% lower than men and cisatracurium Cp at T1 % complete twitch suppression was 21.49% lower than men, a clear pharmacodynamic assertion. Region and weight were significant PopPK covariates. We demonstrated that sex differences are influenced by ethnic-geographic location as only in Chinese women (but not in white women) propofol Cp at LOBR and cisatracurium Cp at T1 % complete twitch suppression were lower than in men. When defining sex differences, ethnic-geographic location should be taken into consideration as a predictive factor for optimizing propofol/cisatracurium initial loading recommended dosages.

Geographic differences in the target-controlled infusion estimated concentration of propofol: bispectral index response curves.

PURPOSE: Variability in drug responses could result from both genetic and environmental factors. Thus, drug effect could depend on geographic location, although regional variation is not generally acknowledged as a basis for stratification. There is evidence that the pharmacokinetic set developed in a European population for the target-controlled infusion (TCI) of propofol does not apply in Chinese patients; however, we are not aware of previous studies comparing the estimated concentration-bispectral index (BIS) response of Caucasian patients in Europe with that of Chinese patients in China. METHODS: The Diprifusor™ TCI pump, incorporating the pharmacokinetic model proposed by Marsh et al., was applied to 30 Caucasian patients in Austria and 30 Chinese patients in China. The estimated plasma concentration (C(p)) of propofol for the two groups was set at 1 µg·mL(-1) and increased by 1 µg·mL(-1) every minute to gradually reach 5 µg·mL(-1) after 5 min. The BIS values were fitted against the estimated C(p) and the predicted effect-site concentration (C(e)) in a sigmoid E(max) model. RESULTS: The sigmoid E(max) curves were shifted significantly to the left in the Chinese group compared with the Austrian group. After 5 min, the BIS value in the Chinese group was lower than in the Austrian group (mean ± standard deviation [SD], 47.2 ± 3.6 vs 63.6 ± 5.4, respectively; P = 0.0006). The estimated C(p) at loss of consciousness (LOC), predicted C(e) at LOC, and time to LOC, were lower in the Chinese group than in the Austrian group (3.3 ± 0.8 µg·mL(-1), 1.6 ± 0.4 µg·mL(-1), 2.8 ± 0.6 min, respectively, vs 4.6 ± 2.8 µg·mL(-1), 2.4 ± 1.5 µg·mL(-1), 3.9 ± 0.5 min, respectively; P < 0.0001). CONCLUSION: When propofol is given using the same TCI protocol, Chinese patients in China lost consciousness faster and at a lower estimated plasma concentration than Caucasians in Austria. Larger studies are needed to map geographically appropriate TCI infusion models.

Propofol-Bispectral Index (BIS) Electroencephalography (EEG) Pharmacokinetic-Pharmacodynamic Model in Patients With Post-Cerebral Hemorrhage Hydrocephalus.

Background. Titrating hypnotic agents for patients who suffer from a cerebral insult is a challenging task. To date there is no real gold standard to precisely quantify electroencephalography (EEG) response in a fashion that could be utilized for patients with post-cerebral hemorrhage hydrocephaly. While we must administer "as per usual" analgesics for noxious stimuli, we have to administer the hypnotic agents more "sparingly" due to lack of objective monitoring. Methods. We compared 15 adult post-cerebral hemorrhage hydrocephalus patients undergoing ventriculo-peritoneal shunt placement with 15 controls matched for gender and approximate age. We set propofol target controlled infusion estimated plasma concentrations (Cp) to gradually reach 4 µg/mL over 4 minutes. To precisely quantify post-cerebral hemorrhage mental dysfunction, we used electronically retrieved bispectral index (BIS) and propofol Cp data points to create individual inhibitory monophasic mathematical model for each patient that incorporates an independent hysteresis "lag" function. Results. In post-cerebral hemorrhage patients Cp-BIS curve, C50 (propofol concentration associated with inhibitory 50% BIS response) cutoff point was significantly shifted to the left by 39%. Whereas before infusion and at stable propofol 4 µg/mL aneurismal surgical sides ipsilateral (75 ± 13, 25 ± 9) and contralateral (73 ± 15, 27 ± 9) mean ± SD BIS values were significantly lower than ipsilateral (95 ± 3, 46 ± 12) and contralateral (94 ± 3, 46 ± 12) matched controls. Conclusions. Using BIS as surrogate marker of propofol hypnotic effect, BIS monitoring in patients with post-cerebral hemorrhage hydrocephaly showed a pattern of change and trend that was similar albeit 39% significantly lower than subjects without.

BIS-vista occipital montage in patients undergoing neurosurgical procedures during propofol-remifentanil anesthesia.

BACKGROUND: Neurosurgical procedures that require a frontal approach could be an impediment for a successful Bispectral Index (BIS) frontal sensor placement. The aim of this study was to explore the utility of using the new BIS-Vista monitor (Aspect Medical Systems, Newton, MA) for occipital sensor placement in the patients undergoing brain neurosurgical procedures during propofol-remifentanil anesthesia. METHODS: Two BIS Quatro sensors (Aspect Medical Systems, Newton, MA) mounted on the occipital and frontal regions were connected to two BIS-Vista monitors at three anesthesia states: before induction, during anesthesia maintenance, and recovery. RESULTS: There were significant differences before induction (P = 0.0002) and at anesthesia maintenance (P = 0.0014) between mean +/- SD occipital (83.4 +/- 4.8, 66.7 +/- 7.2) and frontal (93.1 +/- 3.4, 56.9 +/- 9.1) BIS-Vista values. During anesthesia recovery, there was no difference (P = 0.7421) between occipital (54.6 +/- 9.3) and frontal (53.1 +/- 7.3) BIS-Vista values. Bland and Altman analysis revealed a BIS-Vista negative-bias (limits of agreement) of -9.7 (+1.1, -20.5) before anesthesia induction, +9.8 positive-bias (+22.8, -1.7) during anesthesia maintenance, and -0.9 bias (+10.9, -12.8) during anesthesia recovery. CONCLUSION: We demonstrated that not only the regional limits of agreement are too wide to allow data of the two montages to be used interchangeably but also the variation is a function of anesthetic depth. However, keeping in mind a relatively consistent BIS-Vista -10 bias before induction and +10 bias during anesthesia maintenance with limits of agreement of approximately +/-11 BIS units, approximately double the clinically acceptable less than 10 BIS units level of agreement, BIS-Vista off-label occipital montage might be helpful in following a trend of propofol-remifentanil anesthesia in individual cases where frontal access is particularly difficult.

Benefits and boundaries of processed electroencephalography (pEEG) monitors when they do not concur with standard anesthetic clinical monitoring: lights and shadows.

Numerous clinical conditions that have a direct effect on electroencephalography (EEG) cerebral function could also directly influence brain function monitors (BFM) indices. There is no conventional comparator technology for BFM assessment. The conventional comparator technology used as a benchmark for assessing BFMs technologies chosen by the UK National Institute for Health and Care Excellence (NICE) to reflect the currently used standards in the National Health Service (NHS), was demarcated as "standard anesthetic clinical monitoring" and precisely defined as "the combination of routine clinical observation and electronic monitoring used in clinical practice to assess the adequacy of anesthesia." Because BFMs are EEG-derived parameters, all conditions that can "alter" the raw EEG signal would subsequently change BFM indices to reflect other unrelated EEG events of patient-dependent pathophysiologic perturbations. In many instances we are often confronted with disparate BFM values that do not concur with "standard anesthetic clinical monitoring". Changes in BFM indices during acute cerebral pathology would be highly beneficial to trained informed clinicians as it alerts to something they would not otherwise be aware was happening. This fact-based, citation-supported, narrative review article provides better understanding of BFMs' limitations through examining various published reports of all values that did not coincide with a "standard anesthetic clinical monitoring" whether arising from an underlying alteration of patients' own EEG or those due to shortcomings in the BFM design or performance. The notion of just "riding the numbers" seems to be not a good anesthesia practice; rather we should interpret these BFM indices within context and limitations.

Effect of flumazenil on bispectral index monitoring in unpremedicated patients.

BACKGROUND: Flumazenil is an imidazobenzodiazepine that promptly reverses via competitive inhibition the hypnotic/sedative effects of benzodiazepines on gamma-aminobutyric acid receptors. Endogenous benzodiazepine ligands (endozepines) were isolated in urine, cerebrospinal fluid, and breast milk of women who had not received benzodiazepines. The bispectral index (BIS), an electroencephalographically derived parameter widely used for monitoring the effects of anesthetic/hypnotic drugs, was shown to correlate to various conditions that could influence electroencephalography. The authors examined the hypothesis that 0.5 mg of flumazenil administered to healthy unpremedicated patients during deep surgical remifentanil/propofol anesthesia would increase the BIS value and might expedite recovery from anesthesia. METHODS: Sixty healthy unpremedicated patients were randomly allocated to the flumazenil or control groups. After study drug administration, the authors compared BIS values and various recovery parameters in the flumazenil and control groups. RESULTS: BIS baseline values in the flumazenil group (38.7 +/- 3.8) increased 15 min after flumazenil administration (53.2 +/- 4.7), with a significant difference over time (P < 0.0001) between the two groups. Mean recovery parameters time, comprising time to spontaneous breathing, eye opening/hand squeezing on verbal command, extubation, and date of birth recollection, was significantly shorter (P = 0.0002) in the flumazenil group (6.9 +/- 2.6 min) compared with the control group (9.8 +/- 2.9 min). CONCLUSIONS: This study demonstrates that flumazenil given to healthy unpremedicated patients during propofol/remifentanil anesthesia significantly increased the BIS value and allowed earlier emergence from anesthesia. This may indicate that flumazenil could be used on a case-by-case basis to reverse endogenous or exogenous endozepines that might play a role during anesthesia.

Bispectral index monitoring of a narcolepsy-cataplexy episode during regional anesthesia.

Narcolepsy or Gélineau syndrome is an extremely incapacitating chronic sleep disorder of unknown etiology that is characterized by uncontrollable attacks of deep sleep and is typically associated with cataplexy sudden loss of muscle tone. The Bispectral Index (BIS), an electroencephalographic-derived cerebral monitor, used for monitoring the effects of anesthetic/hypnotic drugs was shown to correlate to various conditions that could influence the eletroencephalogram. We assessed the utility of using BIS for monitoring a possible narcolepsy-cataplexy episode and whether a distinctive BIS profile might offer an early warning of an impending narcoleptic/cataplectic spell. We recorded both hemispheres, using two synchronized BIS-XP monitors, during a narcolepsy-cataplexy episode in a 57-yr-old male patient undergoing lower limb surgery under femoral nerve block regional anesthesia. The patient went through three stages: first a prodromal "intermittent low-vigilance" phase interrupted by high electromyographic activity. This was followed by a second "continuous low-vigilance" phase of BIS around 75 with low electromyographic activity, ending with a third "nonresponsive vigilance" phase of a full-blown narcolepsy-cataplexy episode of BIS around 45 with complete loss of muscle power. The purpose of presenting this report is to emphasize the fact that narcoleptic patients can still run the risk of loss of consciousness with atonia under regional anesthesia, and such an undesirable complication cannot be under-estimated. BIS monitoring is a simple method that could offer an early warning of an imminent episode, with its associated hazards, in patients with narcolepsy-cataplexy undergoing surgery under regional anesthesia.