Detection of Motor Cerebral Activity After Median Nerve Stimulation During General Anesthesia (STIM-MOTANA): Protocol for a Prospective Interventional Study.

BACKGROUND: Accidental awareness during general anesthesia (AAGA) is defined as an unexpected awareness of the patient during general anesthesia. This phenomenon occurs in 1%-2% of high-risk practice patients and can cause physical suffering and psychological after-effects, called posttraumatic stress disorder. In fact, no monitoring techniques are satisfactory enough to effectively prevent AAGA; therefore, new alternatives are needed. Because the first reflex for a patient during an AAGA is to move, but cannot do so because of the neuromuscular blockers, we believe that it is possible to design a brain-computer interface (BCI) based on the detection of movement intention to warn the anesthetist. To do this, we propose to describe and detect the changes in terms of motor cortex oscillations during general anesthesia with propofol, while a median nerve stimulation is performed. We believe that our results could enable the design of a BCI based on median nerve stimulation, which could prevent AAGA. OBJECTIVE: To our knowledge, no published studies have investigated the detection of electroencephalographic (EEG) patterns in relation to peripheral nerve stimulation over the sensorimotor cortex during general anesthesia. The main objective of this study is to describe the changes in terms of event-related desynchronization and event-related synchronization modulations, in the EEG signal over the motor cortex during general anesthesia with propofol while a median nerve stimulation is performed. METHODS: STIM-MOTANA is an interventional and prospective study conducted with patients scheduled for surgery under general anesthesia, involving EEG measurements and median nerve stimulation at two different times: (1) when the patient is awake before surgery (2) and under general anesthesia. A total of 30 patients will receive surgery under complete intravenous anesthesia with a target-controlled infusion pump of propofol. RESULTS: The changes in event-related desynchronization and event-related synchronization during median nerve stimulation according to the various propofol concentrations for 30 patients will be analyzed. In addition, we will apply 4 different offline machine learning algorithms to detect the median nerve stimulation at the cerebral level. Recruitment began in December 2022. Data collection is expected to conclude in June 2024. CONCLUSIONS: STIM-MOTANA will be the first protocol to investigate median nerve stimulation cerebral motor effect during general anesthesia for the detection of intraoperative awareness. Based on strong practical and theoretical scientific reasoning from our previous studies, our innovative median nerve stimulation-based BCI would provide a way to detect intraoperative awareness during general anesthesia. TRIAL REGISTRATION: Clinicaltrials.gov NCT05272202; https://clinicaltrials.gov/ct2/show/NCT05272202. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/43870.

Protocol of DEXPED trial: efficacy of intravenous dexamethasone, administered at the time of analgesic blocking of the lower limb, on postoperative pain in children: a randomised, placebo-controlled, double-blind trial.

INTRODUCTION: Dexamethasone is a drug used to prolong the postoperative analgesia in children after peripheral nerve blockade, although the dose usually used (0.2 mg/kg) has not been studied yet. This study is a monocentric, prospective, randomised, placebo-controlled, double-blinded study in a university hospital in France. The primary objective of the study is to evaluate the efficacy of 0.2 mg/kg intravenous dexamethasone on early postoperative pain in children aged 6-15 years, who require a lower limb peripheral nerve block following general anaesthesia. METHODS AND ANALYSIS: Eighty children, aged 6-15 years, undergoing surgery for which peripheral nerve lower limb blockade with ropivacaine following general anaesthesia are included. The inclusion criteria are: children aged 6-15 years, with American Society of Anaesthesiologists physical status I or II and scheduled for surgery requiring a peripheral block of the lower limb for analgesic purposes, with a preoperative anaesthetic evaluation between 90 and 2 days before the surgery, with informed consent from legal representatives. General anaesthesia is performed. The patient receives, according to his group, either 0.2 mg/kg of dexamethasone intravenously at the start of anaesthetic induction or the same volume of placebo. Then, the peripheral block of the lower limb is performed with ropivacaine. The primary outcome is the total doses of opioid administered (in mg/kg of morphine equivalent) within 24 hours postoperatively. The secondary objectives are the evaluation of the effect of a single-dose intravenous dexamethasone at the time of anaesthetic induction, on the following parameters: onset of postoperative pain, duration of motor block, postoperative nausea and vomiting within 24 hours. ETHICS AND DISSEMINATION: This study is conducted according to the principles of the Declaration of Helsinki and has been approved by the French national ethics committee and the National Drug Safety Agency. Findings of this study will be widely disseminated through conference presentations, reports, factsheets and academic publications. TRIAL REGISTRATION NUMBER: NCT03618173.

Guidelines on muscle relaxants and reversal in anaesthesia.

OBJECTIVES: To provide an update to the 1999 French guidelines on "Muscle relaxants and reversal in anaesthesia", a consensus committee of sixteen experts was convened. A formal policy of declaration and monitoring of conflicts of interest (COI) was developed at the outset of the process and enforced throughout. The entire guidelines process was conducted independently of any industrial funding (i.e. pharmaceutical, medical devices). The authors were required to follow the rules of the Grading of Recommendations, Assessment, Development and Evaluation (GRADE®) system to assess the quality of the evidence on which the recommendations were based. The potential drawbacks of making strong recommendations based on low-quality evidence were stressed. Few of the recommendations remained ungraded. METHODS: The panel focused on eight questions: (1) In the absence of difficult mask ventilation criteria, is it necessary to check the possibility of ventilation via a facemask before muscle relaxant injection? Is it necessary to use muscle relaxants to facilitate facemask ventilation? (2) Is the use of muscle relaxants necessary to facilitate tracheal intubation? (3) Is the use of muscle relaxants necessary to facilitate the insertion of a supraglottic device and management of related complications? (4) Is it necessary to monitor neuromuscular blockade for airway management? (5) Is the use of muscle relaxants necessary to facilitate interventional procedures, and if so, which procedures? (6) Is intraoperative monitoring of neuromuscular blockade necessary? (7) What are the strategies for preventing and treating residual neuromuscular blockade? (8) What are the indications and precautions for use of both muscle relaxants and reversal agents in special populations (e.g. electroconvulsive therapy, obese patients, children, neuromuscular diseases, renal/hepatic failure, elderly patients)? All questions were formulated using the Population, Intervention, Comparison and Outcome (PICO) model for clinical questions and evidence profiles were generated. The results of the literature analysis and the recommendations were then assessed using the GRADE® system. RESULTS: The summaries prepared by the SFAR Guideline panel resulted in thirty-one recommendations on muscle relaxants and reversal agents in anaesthesia. Of these recommendations, eleven have a high level of evidence (GRADE 1±) while twenty have a low level of evidence (GRADE 2±). No recommendations could be provided using the GRADE® system for five of the questions, and for two of these questions expert opinions were given. After two rounds of discussion and an amendment, a strong agreement was reached for all the recommendations. CONCLUSION: Substantial agreement exists among experts regarding many strong recommendations for the improvement of practice concerning the use of muscle relaxants and reversal agents during anaesthesia. In particular, the French Society of Anaesthesia and Intensive Care (SFAR) recommends the use of a device to monitor neuromuscular blockade throughout anaesthesia.

Use of a train-of-four ratio of 0.95 versus 0.9 for tracheal extubation: an exploratory analysis of POPULAR data.

BACKGROUND: The prospective observational European multicentre cohort study (POPULAR) of postoperative pulmonary complications (NCT01865513) did not demonstrate that adherence to the recommended train-of-four ratio (TOFR) of 0.9 before extubation was associated with better pulmonary outcomes from the first postoperative day up to hospital discharge. We re-analysed the POPULAR data as to whether there existed a better threshold for TOFR recovery before extubation to reduce postoperative pulmonary complications in patients who had quantitative neuromuscular monitoring (87% acceleromyography). METHODS: To identify the optimal TOFR, the complete case cohort of patients with quantitative neuromuscular monitoring (n=3150) was split into several pairs of sub-cohorts related to TOFR values from 0.86 to 0.96; values of 0.97 and higher could not be used as the sub-cohorts were too small. The optimal TOFR was considered to have the lowest P-value from multivariate logistic regression calculated for each of the TOFR values. Data are presented as adjusted absolute risk reduction or median difference with 95% confidence interval. RESULTS: Extubating patients with TOFR >0.95 rather than >0.9 reduced the adjusted risk of postoperative pulmonary complications by 3.5% (0.7-6.0%) from that reported in POPULAR (11.3%). Increasing the recommended TOFR from 0.9 to 0.95 reduced the adjusted risk by 4.9% (1.2-8.5%). Sub-cohorts resulting from 1:1 propensity score matching revealed that sugammadex had been given in higher doses by 0.30 (0.13-0.48) mg kg-1 in the sub-cohort with TOFR > 0.95. CONCLUSIONS: A post hoc analysis of patients receiving quantitative monitoring of neuromuscular function suggests that postoperative pulmonary complications are reduced for TOFR > 0.95 before tracheal extubation compared with TOFR > 0.9. TRIAL REGISTRATION NUMBER: NCT01865513.

How to optimize neuromuscular blockade in ambulatory setting?

PURPOSE OF REVIEW: The purpose of this review is to discuss the optimal use of neuromuscular blocking agents (NMBA) during ambulatory surgery, and to provide an update on the routine use of neuromuscular monitoring and the prevention of residual paralysis. RECENT FINDINGS: The number of major surgical procedures performed in ambulatory patients is likely to increase in the coming years, following the development of laparoscopic and thoracoscopic procedures. To successfully complete these procedures, the proper use of NMBA is mandatory. The use of NMBA not only improves intubating conditions but also ventilation. Recent studies demonstrate that NMBA are much more the solution rather than the cause of airway problems. There is growing evidence that the paralysis of the diaphragm and the abdominal wall muscles, which are resistant to NMBA is of importance during laparoscopic surgery. Further studies are still required to determine when deep neuromuscular block [posttetanic count (PTC) < 5] is required perioperatively. There is now a consensus to use perioperatively neuromuscular monitoring and particularly objective neuromuscular monitoring in combination with reversal agents to avoid residual paralysis and its related morbidity (e.g. respiratory complications in the PACU). SUMMARY: Recent data suggest that it is now possible to obtain a tight control of neuromuscular block to maintain optimal relaxation tailored to the surgical requirements and to obtain a rapid and reliable recovery at the end of the procedure.

Antibiotic prophylaxis with high-dose cefoxitin in bariatric surgery: an observational prospective single center study.

BACKGROUND: The optimal dose of cefoxitin for antibiotic prophylaxis in obese patients remains uncertain. We evaluated the adequacy of a 4-gram dosing regimen of cefoxitin against the most frequent pathogens that infect patients undergoing bariatric surgery. METHODS: This observational prospective study included obese patients who required bariatric surgery and a 4-gram dose of cefoxitin as an antibiotic prophylaxis. Serum concentrations were measured during surgery (incision, wound closure and in case of reinjection). The pharmacokinetic/pharmacodynamic (PK/PD) target was to obtain free cefoxitin concentrations above 4× MIC, from incision to wound closure (100% ƒT>4xMIC). The targeted MIC was based on the worst-case scenario (the highest ECOFF value of Staphylococcus aureus, Enterobacteriaceae and anaerobic bacteria). The secondary outcomes were the factors related to underdosage. RESULTS: Two hundred patients were included. The mean age of the patients was 46 (±12) years-old, and the mean BMI was 45.8 (±6.9) kg/m2 Bypass surgery was the preferred technique (84%). The percentages of patients who met the PK/PD target (100% fT>4xMIC) of cefoxitin were 37.3%, 1.1% and 0% for S. aureus, Enterobacteriaceae and anaerobic bacteria, respectively. BMIs below 50 kg/m2 (OR 0.29, 95% CI [0.11-0.75], P = 0.0107) and a shorter duration of surgery (OR 0.97, 95% CI [0.95-0.99], P = 0.004) were associated with reaching the target concentrations. CONCLUSIONS: In obese patients undergoing bariatric surgery, a regimen of 4 grams of cefoxitin led to an inadequate coverage for most common pathogens. A longer surgery duration and BMI over 50 kg/m2 increase the risk of underdosage.

MOTANA: study protocol to investigate motor cerebral activity during a propofol sedation.

BACKGROUND: Accidental Accidental awareness during general anesthesia (AAGA) occurs in 1-2% of high-risk practice patients and is a cause of severe psychological trauma, termed post-traumatic stress disorder (PTSD). However, no monitoring techniques can accurately predict or detect AAGA. Since the first reflex for a patient during AAGA is to move, a passive brain-computer interface (BCI) based on the detection of an intention of movement would be conceivable to alert the anesthetist. However, the way in which propofol (i.e., an anesthetic commonly used for the general anesthesia induction) affects motor brain activity within the electroencephalographic (EEG) signal has been poorly investigated and is not clearly understood. For this reason, a detailed study of the motor activity behavior with a step-wise increasing dose of propofol is required and would provide a proof of concept for such an innovative BCI. The main goal of this study is to highlight the occurrence of movement attempt patterns, mainly changes in oscillations called event-related desynchronization (ERD) and event-related synchronization (ERS), in the EEG signal over the motor cortex, in healthy subjects, without and under propofol sedation, during four different motor tasks. METHODS: MOTANA is an interventional, prospective, exploratory, physiological, monocentric, and randomized study conducted in healthy volunteers under light anesthesia, involving EEG measurements before and after target-controlled infusion of propofol at three different effect-site concentrations (0 µg.ml -1, 0.5 µg.ml -1, and 1.0 µg.ml -1). In this exploratory study, 30 healthy volunteers will perform 50 trials for the four motor tasks (real movement, motor imagery, motor imagery with median nerve stimulation, and median nerve stimulation alone) in a randomized sequence. In each conditions and for each trial, we will observe changes in terms of ERD and ERS according to the three propofol concentrations. Pre- and post-injection comparisons of propofol will be performed by paired series tests. DISCUSSION: MOTANA is an exploratory study aimed at designing an innovative BCI based on EEG-motor brain activity that would detect an attempt to move by a patient under anesthesia. This would be of interest in the prevention of AAGA. TRIAL REGISTRATION: Agence Nationale de Sécurité du Médicament (EUDRACT 2017-004198-1), NCT03362775. Registered on 29 August 2018. https://clinicaltrials.gov/ct2/show/NCT03362775?term=03362775&rank=1.

Deep neuromuscular blockade improves surgical conditions during gastric bypass surgery for morbid obesity: A randomised controlled trial.

BACKGROUND: There is a controversy in the literature whether deep compared with moderate neuromuscular block (NMB) improves surgical conditions for laparoscopic surgery. OBJECTIVES: The primary outcome measure was to examine whether switching from moderate to deep NMB improves surgical conditions for laparoscopic surgery in the obese; secondary outcome measures were changes in intra-abdominal pressure, time required to perform the gastrojejunal anastomosis and peri-operative surgical complications. DESIGN: A single-centre, randomised controlled study. Each patient was taken as their own control and examined twice: at the first evaluation (E1), all patients had a moderate NMB, thereafter patients were randomised to deep or moderate block and a second evaluation (E2) was performed within 10 min. Patients with excellent rating at E1 were excluded from E2, as their surgical condition could not be further improved. SETTING: University Hospital France. PATIENTS: Patients undergoing laparoscopic gastric bypass surgery under general anaesthesia were included. Main exclusion criteria were hypersensitivity to the drugs used and absence of written informed consent. INTERVENTIONS: According to the group assignment, patients received bolus doses of rocuronium or 0.9% saline. MAIN OUTCOME MEASURES: Surgical conditions were assessed with a 4-point rating scale. Intra-operative adverse events were assessed with the Kaafarani-classification and postoperative complications with the Clavien-Dindo classification. RESULTS: Eighty-nine patients were initially included and data from 85 could be assessed at E1; surgical rating was excellent in 20, good in 35, acceptable in 18, poor in 12. After excluding those with an excellent rating, the remaining 65 patients were randomly assigned to deep or moderate block. At E2, an improvement of surgical conditions was observed in 29 out of 34 patients with deep block and in four out of 31 with moderate block; P < 0.0001. Poor surgical conditions were more frequently associated with surgical complications (61.5 versus 15.3%; P < 0.001). CONCLUSION: Switching from moderate to deep block improves surgical conditions. Poor surgical conditions were associated with a higher incidence of surgical complications. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02118844.

Post-anaesthesia pulmonary complications after use of muscle relaxants (POPULAR): a multicentre, prospective observational study.

BACKGROUND: Results from retrospective studies suggest that use of neuromuscular blocking agents during general anaesthesia might be linked to postoperative pulmonary complications. We therefore aimed to assess whether the use of neuromuscular blocking agents is associated with postoperative pulmonary complications. METHODS: We did a multicentre, prospective observational cohort study. Patients were recruited from 211 hospitals in 28 European countries. We included patients (aged ≥18 years) who received general anaesthesia for any in-hospital procedure except cardiac surgery. Patient characteristics, surgical and anaesthetic details, and chart review at discharge were prospectively collected over 2 weeks. Additionally, each patient underwent postoperative physical examination within 3 days of surgery to check for adverse pulmonary events. The study outcome was the incidence of postoperative pulmonary complications from the end of surgery up to postoperative day 28. Logistic regression analyses were adjusted for surgical factors and patients' preoperative physical status, providing adjusted odds ratios (ORadj) and adjusted absolute risk reduction (ARRadj). This study is registered with ClinicalTrials.gov, number NCT01865513. FINDINGS: Between June 16, 2014, and April 29, 2015, data from 22 803 patients were collected. The use of neuromuscular blocking agents was associated with an increased incidence of postoperative pulmonary complications in patients who had undergone general anaesthesia (1658 [7·6%] of 21 694); ORadj 1·86, 95% CI 1·53-2·26; ARRadj -4·4%, 95% CI -5·5 to -3·2). Only 2·3% of high-risk surgical patients and those with adverse respiratory profiles were anaesthetised without neuromuscular blocking agents. The use of neuromuscular monitoring (ORadj 1·31, 95% CI 1·15-1·49; ARRadj -2·6%, 95% CI -3·9 to -1·4) and the administration of reversal agents (1·23, 1·07-1·41; -1·9%, -3·2 to -0·7) were not associated with a decreased risk of postoperative pulmonary complications. Neither the choice of sugammadex instead of neostigmine for reversal (ORadj 1·03, 95% CI 0·85-1·25; ARRadj -0·3%, 95% CI -2·4 to 1·5) nor extubation at a train-of-four ratio of 0·9 or more (1·03, 0·82-1·31; -0·4%, -3·5 to 2·2) was associated with better pulmonary outcomes. INTERPRETATION: We showed that the use of neuromuscular blocking drugs in general anaesthesia is associated with an increased risk of postoperative pulmonary complications. Anaesthetists must balance the potential benefits of neuromuscular blockade against the increased risk of postoperative pulmonary complications. FUNDING: European Society of Anaesthesiology.

Short-course antibiotic therapy for critically ill patients treated for postoperative intra-abdominal infection: the DURAPOP randomised clinical trial.

PURPOSE: Shortening the duration of antibiotic therapy (ABT) is a key measure in antimicrobial stewardship. The optimal duration of ABT for treatment of postoperative intra-abdominal infections (PIAI) in critically ill patients is unknown. METHODS: A multicentre prospective randomised trial conducted in 21 French intensive care units (ICU) between May 2011 and February 2015 compared the efficacy and safety of 8-day versus 15-day antibiotic therapy in critically ill patients with PIAI. Among 410 eligible patients (adequate source control and ABT on day 0), 249 patients were randomly assigned on day 8 to either stop ABT immediately (n = 126) or to continue ABT until day 15 (n = 123). The primary endpoint was the number of antibiotic-free days between randomisation (day 8) and day 28. Secondary outcomes were death, ICU and hospital length of stay, emergence of multidrug-resistant (MDR) bacteria and reoperation rate, with 45-day follow-up. RESULTS: Patients treated for 8 days had a higher median number of antibiotic-free days than those treated for 15 days (15 [6-20] vs 12 [6-13] days, respectively; P < 0.0001) (Wilcoxon rank difference 4.99 days [95% CI 2.99-6.00; P < 0.0001). Equivalence was established in terms of 45-day mortality (rate difference 0.038, 95% CI - 0.013 to 0.061). Treatments did not differ in terms of ICU and hospital length of stay, emergence of MDR bacteria or reoperation rate, while subsequent drainages between day 8 and day 45 were observed following short-course ABT (P = 0.041). CONCLUSION: Short-course antibiotic therapy in critically ill ICU patients with PIAI reduces antibiotic exposure. Continuation of treatment until day 15 is not associated with any clinical benefit. CLINICALTRIALS. GOV IDENTIFIER: NCT01311765.

Do we really need sugammadex as an antagonist of muscle relaxants in anesthesia?

PURPOSE OF REVIEW: Sugammadex is a selective relaxant-binding agent that is designed to encapsulate rocuronium and chemically similar steroidal muscle relaxants such as vecuronium. This review summarizes recent information on the use of sugammadex in clinical practice. RECENT FINDINGS: The main advantages of sugammadex when compared with conventional anticholinesterase agents are a much faster recovery time and its unique ability to reverse rapidly and efficiently, for the first time, deep levels of neuromuscular blockade. However, there is paucity of evidence-based studies on the benefit of deep neuromuscular block, and then routine administration of sugammadex to reverse any level of block, for example, during laparoscopic surgery. It appears that reduction of costs depends mainly on organizational factors. Finally it must be remembered that sugammadex only works with steroidal nondepolarizing muscle relaxants; therefore neostigmine should not be withdrawn because it is the only reversal agent effective against atracurium or cisatracurium. SUMMARY: Sugammadex offers a significantly faster and more predictable recovery profile than neostigmine. It is now possible to reverse rapidly and efficiently any level of neuromuscular blockade and to avoid the risk of adverse events because of residual paralysis such as critical respiratory events during recovery from anesthesia.

Biological evaluation of the effect of sugammadex on hemostasis and bleeding.

BACKGROUND: Notification of sugammadex has been supplemented with a section on hemostasis, including a longer clotting time in the first minutes following injection, without any documented clinical consequences. The objective of this observational study was to analyze the effects of sugammadex administration on routine coagulation tests and bleeding in the clinical setting. METHODS: After Institutional Review Board approval, a prospective observational study was conducted between January and December 2011. Adult patients scheduled for laparotomies were analyzed in groups according to the type of reversal (without sugammadex versus 2 or 4 mg/kg sugammadex). There were no changes in our current clinical practice. Blood samples drawn from these patients were standardized at the same time and tested using the same daily calibrated machine. The endpoint was a comparison of the activated partial thromboplastin time (aPTT), prothrombin time (PT), hemoglobin (Hb) level and hematocrit (Ht), immediately before sugammadex administration (H0) and 1 h after neuromuscular block reversal (H1). RESULTS: One hundred and forty-two patients in three groups were included as follows: 11 in the "without sugammadex" group, 64 in the "2 mg/kg sugammadex" group and 67 in the "4 mg/kg sugammadex" group. Results did not differ significantly among the groups. CONCLUSIONS: In this prospective observational study, the use of 2 and 4 mg/kg sugammadex was not associated with a longer clotting time or decreased hemoglobin concentrations. Future prospective investigations should study patients receiving 16 mg/kg sugammadex and/or with abnormal coagulation tests.

Sugammadex: A Scientific Review Including Safety and Efficacy, Update on Regulatory Issues, and Clinical Use in Europe.

Muscle relaxants are used in the perioperative period to aid in endotracheal intubation, facilitate surgical exposure, and in the critical care setting for prolonged relaxation. Until now, the only mechanism to reverse their effect is acetylcholinesterase inhibitors that result in excess parasympathetic activity and require the second drug to prevent this side effect. Additionally, the onset and degree of neuromuscular antagonism are often unpredictable and unreliable. Sugammadex is the first of the cyclodextrins to be used as a therapeutic agent. It quickly, effectively, and safely reverses steroidal neuromuscular blockers by encapsulating the muscle relaxant and rendering it inactive. Sugammadex may be considered the ideal reversal agent and the first drug in its class, which will likely change the practice of anesthesia and clinical neuromuscular pharmacology.

Impact of fluid resuscitation with hypertonic-hydroxyethyl starch versus lactated ringer on hemorheology and microcirculation in hemorrhagic shock.

The choice of volume expander for fluid resuscitation in hemorrhagic shock is still debated. Changes in plasma viscosity (PV) are barely investigated while PV modulates functional capillary density, microcirculation and organ function. The present study evaluated the impact of 2 strategies of fluid resuscitation in hemorrhagic shock in pigs. Ten pigs were subjected to hemorrhagic shock and randomly assigned to a low viscosity fluid regimen (Lactated Ringer's, LR) group or a high viscosity regimen (hypertonic-hydroxyethyl starch, HES) for volume resuscitation. Sublingual microcirculatory flow and tissue oxygen tension were assessed together with macro- and microcirculatory, biochemical and rheological variables at baseline, 30 minutes after hemorrhagic shock, immediately after reaching resuscitation endpoints (R-0), and 60 minutes after resuscitation (R-60). PV decreased similarly in both groups following resuscitation (from 1.36 [1.32-1.38] to 1.21 [1.21-1.23] for LR, and from 1.32 [1.31-1.32] to 1.20 [1.17-1.21] mPa.s for HES). No differences were found between the groups for other rheological variables, microcirculatory flow or tissue oxygen tension at R-0 and R-60. Despite a 6-fold difference in the volumes required to achieve blood flow endpoints, commercially available volume expanders had similar effects on rheological and microcirculatory variables, irrespective of their viscosity. Our findings are consistent with the absence of clinically relevant differences between crystalloid and colloid resuscitation of hemorrhagic shock.

Low-dose neostigmine to antagonise shallow atracurium neuromuscular block during inhalational anaesthesia: A randomised controlled trial.

BACKGROUND: Even shallow residual neuromuscular block [i.e. train-of-four (TOF) ratio around 0.6] is harmful. It can be effectively antagonised by small doses of neostigmine, but reports are limited to intravenous anaesthesia. Inhalational anaesthesia may enhance neuromuscular block and delay recovery. It is not known whether low doses of neostigmine are still effective in the context of inhalational anaesthesia. OBJECTIVE: To assess the effectiveness of low doses of neostigmine to antagonise shallow atracurium block during desflurane anaesthesia. DESIGN: Randomised controlled trial, four groups. SETTING: Single centre, University Hospital, May 2010 to March 2011. PARTICIPANTS: Forty-eight American Society of Anesthesiologists I-III patients undergoing desflurane anaesthesia. INTERVENTION: At TOF ratio 0.6, patients were randomised to one of four treatments (physiological saline, 10, 20 or 30 µg kg(-1) neostigmine, n = 12 for each). MAIN OUTCOME MEASURE: Primary efficacy endpoint: time interval between study drug injection and a TOF ratio more than 0.9 using acceleromyography. Secondary efficacy endpoint: neuromuscular recovery after 5 and 10 min. RESULTS: After physiological saline, the time interval [median (range)] between a TOF ratio of 0.6 and 0.9 was 14 (7 to 18) min. After 10, 20 and 30 µg kg(-1) neostigmine, it was reduced to 5 (3 to 8) min, 5 (3 to 10) and 4 (2 to 6) min, respectively (P < 0.001 compared to physiological saline). At 5 min after physiological saline, the TOF ratio [mean (SD)] was 0.73 (0.05) and 0.91 (0.06), 0.90 (0.10), 0.96 (0.02) after neostigmine 10, 20 or 30 µg kg(-1), respectively (P < 0.01 compared to physiological saline). At 10 min after physiological saline, the TOF ratio was 0.86 (0.08) and 1.0 (0), 0.98 (0.03), 1.0 (0) after neostigmine 10, 20 or 30 µg kg(-1), respectively (P < 0.01 compared to physiological saline). CONCLUSION: Under desflurane anaesthesia, neostigmine 10 µg kg(-1) is effective in antagonising shallow atracurium block. Compared to no neostigmine, the time to a TOF ratio more than 0.9 was shortened and neuromuscular recovery at 5 and 10 min was more advanced. TRIAL REGISTRATION: EudraCT Nr. is 2009 -018214-19.

Motion sickness in rally car co-drivers.

BACKGROUND: Car sickness is a frequent and potentially disabling problem, commonly related to a theory of sensory conflict, in particular visuo-vestibular, and between actual and anticipated sensory signals. This study aimed to evaluate predictors of motion sickness (MS) in rally car co-drivers exposed to various accelerations. METHODS: The subjects were 85 rally co-drivers (21 women) who filled in a questionnaire investigating MS symptoms in 4 situations: 1) special stages (competition itself); 2) special stages reconnaissance; 3) reading a book in the car; and 4) rear-seat passenger. The main factors related to MS were also investigated. RESULTS: Women reported more MS than men only in the rear-seat passenger situation. MS is reported with increasing frequency in special stages (2.3%), special stages reconnaissance (15.3%), when reading a book in a car (25.9%), and as a rear-seat passenger (25.9%). Stress (63.0%), on-board smells (46.5%), and on-board temperature (43.0%) were the main risk factors for MS. DISCUSSION: In special stages, the lower MS occurrence could be related to the kind of visual input: central vision focuses mainly on accurate pace notes while peripheral vision is restricted by the crash helmet and the head being bent forward. A cognitive process involved in the interpretation of the dynamic environment may lead to anticipation of upcoming accelerations, optimizing integration of vestibular and proprioceptive signals. During reconnaissance, the constant change of gaze between looking at the specifics of the road and the road book for taking notes requires frequent adjustments of the gain of the vestibulo-ocular reflex and the associated head movements could generate Coriolis accelerations.