Topical Anaesthesia Using a Soft Mist Spray Device Allows Comfortable Awake Visualisation of the Airway via Self-Videolaryngoscopy in Volunteers.

Background: During endotracheal intubation, there is a 10% incidence of difficult laryngoscopy, which may result in serious complications. It is important to obtain as much information about the visibility of laryngeal structures before the patient is anaesthetised. Performing awake (video-) laryngoscopy on a patient is uncomfortable and can trigger gagging and coughing reflexes, making visualisation nearly impossible. The objective of this study is to evaluate the effectiveness of a soft mist spray device for airway anaesthesia during awake (video-) laryngoscopy. Methods: Twenty healthy volunteers inhaled through the Trachospray device, which was placed in their mouths. Two 2 mL syringes containing lidocaine at 4% were sprayed into the airway during inspiration. After several minutes, the subjects were asked to perform a videolaryngoscopy on themselves until the glottic structures and the vocal cords were visible. Upon completion of the procedure, all participants were asked to fill out a feedback form. Results: The duration of the videolaryngoscopy to visualisation of the vocal cords averaged 17 ± 13 s. After analysing the data, three distinct groups emerged as follows: Group 1 (70% of participants) showed no response, allowing for easy insertion of the videolaryngoscope. Group 2 (25% of participants) exhibited a light response but still permitted easy insertion and visualisation. One patient demonstrated a clear response with noticeable laryngeal contraction, requiring slightly more effort and discomfort for insertion. In 80% of the participants, the laryngeal structures were visualised according to Cormack-Lehane grade 1. All participants reported a high level of comfort, with an average rating of NRS 8. The anaesthesiologist assessed the level of anaesthesia as good to very good. No adverse events were observed. Conclusions: The Trachospray provided good, reliable, comfortable, and safe topical anaesthesia for awake videolaryngoscopy. This enables a direct visual assessment of the airway and may assist in making decisions regarding airway management for tracheal intubation.

Postoperative pain reduction by pre-emptive N-acetylcysteine: an exploratory randomized controlled clinical trial.

BACKGROUND: A new potential target for multimodal pain management is the group-II metabotropic glutamate receptor subtypes, which can be activated by N-acetylcysteine. We investigated whether pre-emptive administration of N-acetylcysteine leads to a reduction in postoperative pain after laparoscopic inguinal hernia repair. METHODS: Sixty American Society of Anesthesiologists I-II patients scheduled for elective inguinal hernia repair were randomized to receive either N-acetylcysteine (150 mg/kg) or placebo intravenously 1 hour before surgery. The primary outcome was the visual analogue score during movement in the morning (approximately 24 hours) after surgery. Among secondary outcomes were postoperative opioid consumption and safety of intravenous N-acetylcysteine. RESULTS: In total, 23 patients were analyzed per group. Pain scores were similar at all timepoints with a 24 hours median score of 34 (IQR of 19.0 to 42.5) in the N-acetylcysteine group and a median score of 26 (16.0 to 50.0) in the placebo group. The percentage of patients using opioids after surgery was 22% versus 39% day 1 (p=0.63); 9% versus 26% day 2 (p=0.14); 9% versus 17% day 3 (p=0.35) in the N-acetylcysteine group compared with placebo group. Side effects resembling anaphylactoid reactions in response to the administration of N-acetylcysteine were present in more than half of the patients. CONCLUSIONS: Without finding important differences between N-acetylcysteine and placebo group in pain scores postoperatively, but with a high percentage of bothersome side effects for the N-acetylcysteine group, we would not recommend the use of pre-emptive intravenous N-acetylcysteine to reduce postoperative pain in laparoscopic inguinal hernia repair patients based on this study. TRIAL REGISTRATION NUMBER: NCT03354572.

Comparative in-vitro Study of the Trachospray, a New Device for Topical Anaesthesia of the Upper Airway.

BACKGROUND: Obtaining complete topical anaesthesia of the airway remains a clinical challenge. Particle size is one of the most important variables for the dose deposited and the distribution of aerosols in the airways. The mass median aerodynamic diameter of the particles should be in the range of 5-20 µm. We developed the "Trachospray" as a soft mist spray device for local anaesthetics. This in-vitro comparative test was designed to compare the performance of the new Trachospray device with two existing medical devices. The performance was determined by comparing the spray deposition patterns in the mouth, throat, trachea and lungs. METHODS: The human airway was simulated with an artificial idealized mouth and throat model, connected to a Next Generation Impactor. Four measurements were taken for each device (Trachospray, jet nebulizer and a spray pump) with 5.85% NaCl. A fifth measurement was carried out with 0.5% fluorescein solution for a visual inspection of the deposition patterns. The mass median aerodynamic diameter and geometric standard deviation of the droplets were measured. RESULTS: The Trachospray produced an even coverage in the mouth, hypopharynx and vocal cords, with only a small lung fraction. The jet nebulizer produced a much thinner layer coverage of the tongue and surface around the vocal chords with a high lung deposition. The spray pump produced big droplets which deposited mainly at the hypopharynx. CONCLUSION: The Trachospray device deposits local anaesthetics in the targeted areas for topical anaesthesia of the airway and has promising characteristics for providing effective airway anaesthesia.

Emergency physician-performed ultrasound-guided nerve blocks in proximal femoral fractures provide safe and effective pain relief: a prospective observational study in The Netherlands.

BACKGROUND: The treatment of acute pain in the emergency department is not always optimal. Peripheral nerve blocks using "blind" or nerve stimulator techniques have substantial disadvantages. Ultrasound-guided regional anesthesia may provide quick, safe, and effective pain relief in patients with proximal femoral fractures with severe pain. However, no evidence exists on emergency physician-performed ultrasound-guided regional anesthesia in these patients in Dutch emergency departments. We hypothesized that emergency physicians can be effectively trained to safely perform and implement ultrasound-guided femoral nerve blocks, resulting in effective pain relief in patients with proximal femoral fractures. METHODS: In this prospective observational study, emergency physicians were trained by expert anesthesiologists to perform ultrasound-guided femoral nerve blocks during a single-day course. Femoral nerve blocks were performed on patients with proximal femoral fractures. A system of direct supervision by skilled anesthesiologists and residents was put in place. RESULTS: A total of 64 femoral nerve blocks were performed. After 30 min, blocks were effective in 69% of patients, and after 60 min, in 83.3%. The mean reduction in pain scores after 30 and 60 min was 3.84 and 4.77, respectively (both p <  0.001). Patients reported a mean satisfaction of 8.42 (1 to 10 scale). No adverse events occurred. CONCLUSIONS: Ultrasound-guided femoral nerve block is an effective, safe, and easy to learn (single-day course) procedure for emergency physicians to implement and perform in the emergency department. Patient satisfaction was high.

Proper training and use of ultrasonography facilitates lumbar puncture.

With great interest, we read the study of Line Dussourd et al. concluding that ultrasonography allows better identification of anatomical structures before performing a lumbar puncture. We cannot concur with the conclusions of the study because the authors did not visualize the conus medullaris directly, nor did they assess the individual intervertebral levels. In our commentary, we make some suggestions for improvement using ultrasound to locate the optimal site for a lumbar puncture. We do agree that neuraxial ultrasound is of great benefit for the performance of lumbar punctures. Proper training and applying the correct technique, however, is necessary for obtaining all benefits ultrasonography offers.

Helping Children Cope with Medical Tests and Interventions.

Medical procedures and tests become a challenge when anxiety and pain make it difficult for the patient to cooperate or remain still when needed. Fortunately a short intervention with hypnoidal language at the onset of a procedure induces a positive and sustained change in the way pain and anxiety are processed. While anesthesia may appear to be a simple solution to eliminate pain, the adverse effects of pre-anesthesia anxiety on postoperative behavior and recovery are often not fully appreciated. This paper discusses options for self-hypnotic relaxation that are applicable to interactions with children. The high suggestibility of children makes it relatively easy to engage them in make-believe scenarios. Avoidance of negative suggestions is key in avoiding nocebo effects that may be difficult to overcome later. Once a child is immersed in his or her preferred scenario or hobby/activity of choice, environmental and procedural stimuli can be easily integrated in the imagery. Ego-strengthening metaphors that tie in features of strength, confidence, or resilience are particularly empowering. Even when children are fully under general anesthesia they may still have recall of what is said in the room and therefore caution in word choice should be maintained.

Clinical application of perioperative multimodal analgesia.

PURPOSE OF REVIEW: The experience of intense postoperative pain remains a significant problem in perioperative medicine. The mainstay of postoperative analgetic therapy is the combination of nonopioid agents (e.g. paracetamol and NSAIDs) with strong opioids (e.g. morphine) according to the WHO analgesic ladder. But as the incidence and intensity of postoperative pain remains high, the search for and evaluation of additional concepts is ongoing. This review highlights the current trends of perioperative multimodal analgesia concepts. RECENT FINDINGS: Gabapentinoids, ketamine, dexamethasone and magnesium are effective parts of a multimodal analgesia concept without absolute contraindications and nearly without major negative side effects. Recent publications further define the role of these substances for perioperative use in terms of optimal dosing, positive side effects, relative potency and interaction. SUMMARY: Components of well tolerated and simple advanced multimodal analgesia concepts in the perioperative period are now easy to apply and ready to become a standard in the daily clinical practice.

Metamizole (Dipyrone) as an Alternative Agent in Postoperative Analgesia in Patients with Contraindications for Nonsteroidal Anti-Inflammatory Drugs.

PURPOSE: Nonsteroidal anti-inflammatory drugs (NSAIDs) play an important role in multimodal pain management. In patients with a contraindication for NSAIDs, pain management is challenging. A recent Dutch anesthesiology guideline propagates the use of metamizole (dipyrone) in these patients. Metamizole is a controversial drug, its use being previously discouraged because of the risk for agranulocytosis. We discuss whether metamizole could be an alternative to classical NSAIDs and opioids in postoperative pain management despite this drawback. METHOD: Literature review and pharmacovigilance research based on World Health Organization adverse effect registrations. RESULTS: Metamizole causes fewer gastric and duodenal ulcers than other nonselective NSAIDs, and the risk for bleeding is limited. It is unknown whether it is safer than a nonselective NSAID combined with a proton pump inhibitor. Although the drug appears to be safe for renal function in healthy volunteers, data in high-risk patients (eg, those with heart or renal failure) are lacking. The incidence of metamizole-induced agranulocytosis is controversial, but the risk is likely to be limited with short-term postoperative use in this selected group of patients. CONCLUSION: Although firm evidence is lacking, metamizole may be safer for the upper intestinal tract and kidneys than other NSAIDs, and could alternatively be used in patients with an increased risk for stomach or renal problems. Hereby, improved postoperative pain relief can potentially be achieved. The risk for metamizole-induced agranulocytosis is judged to be acceptable.

Decoding motor responses from the EEG during altered states of consciousness induced by propofol.

OBJECTIVE: Patients undergoing general anesthesia may awaken and become aware of the surgical procedure. Due to neuromuscular blocking agents, patients could be conscious yet unable to move. Using brain-computer interface (BCI) technology, it may be possible to detect movement attempts from the EEG. However, it is unknown how an anesthetic influences the brain response to motor tasks. APPROACH: We tested the offline classification performance of a movement-based BCI in 12 healthy subjects at two effect-site concentrations of propofol. For each subject a second classifier was trained on the subject's data obtained before sedation, then tested on the data obtained during sedation ('transfer classification'). MAIN RESULTS: At concentration 0.5 µg ml(-1), despite an overall propofol EEG effect, the mean single trial classification accuracy was 85% (95% CI 81%-89%), and 83% (79%-88%) for the transfer classification. At 1.0 µg ml(-1), the accuracies were 81% (76%-86%), and 72% (66%-79%), respectively. At the highest propofol concentration for four subjects, unlike the remaining subjects, the movement-related brain response had been largely diminished, and the transfer classification accuracy was not significantly above chance. These subjects showed a slower and more erratic task response, indicating an altered state of consciousness distinct from that of the other subjects. SIGNIFICANCE: The results show the potential of using a BCI to detect intra-operative awareness and justify further development of this paradigm. At the same time, the relationship between motor responses and consciousness and its clinical relevance for intraoperative awareness requires further investigation.

The effect of pregabalin and s-ketamine in total knee arthroplasty patients: A randomized trial.

BACKGROUND AND AIMS: Pain reduction is important for rehabilitation after total knee arthroplasty. Intra- and peri-articular infiltration with local anesthetics may be an alternative to commonly used locoregional techniques. Adding pregabalin orally and s-ketamine intravenously may further reduce postoperative pain. MATERIAL AND METHODS: This prospective, randomized, double-blind, placebo-controlled study compared two methods of perioperative analgesia. Control patients received a standardized multimodal postoperative analgesic regime of paracetamol, diclofenac, and piritramide-patient-controlled analgesia, including ropivacaine knee infiltration during surgery. The study group received pregabalin orally and s-ketamine intravenously as an additional medication to the standard multimodal regimen. The control group received placebo. RESULTS: The study group showed lower piritramide consumption during the first 24 h (P: 0.043), but with more side effects such as diplopia and dizziness. CONCLUSION: Addition of pregabalin and s-ketamine resulted in lower piritramide consumption during the first 24 h postoperatively. However, more investigation on benefits versus side effects of this medication is required.

Optimal Multitrial Prediction Combination and Subject-Specific Adaptation for Minimal Training Brain Switch Designs.

Brain-Computer Interface (BCI) systems are traditionally designed by taking into account user-specific data to enable practical use. More recently, subject independent (SI) classification algorithms have been developed which bypass the subject specific adaptation and enable rapid use of the system. A brain switch is a particular BCI system where the system is required to distinguish from two separate mental tasks corresponding to the on-off commands of a switch. Such applications require a low false positive rate (FPR) while having an acceptable response time (RT) until the switch is activated. In this work, we develop a methodology that produces optimal brain switch behavior through subject specific (SS) adaptation of: a) a multitrial prediction combination model and b) an SI classification model. We propose a statistical model of combining classifier predictions that enables optimal FPR calibration through a short calibration session. We trained an SI classifier on a training synchronous dataset and tested our method on separate holdout synchronous and asynchronous brain switch experiments. Although our SI model obtained similar performance between training and holdout datasets, 86% and 85% for the synchronous and 69% and 66% for the asynchronous the between subject FPR and TPR variability was high (up to 62%). The short calibration session was then employed to alleviate that problem and provide decision thresholds that achieve when possible a target FPR=1% with good accuracy for both datasets.

Detection of attempted movement from the EEG during neuromuscular block: proof of principle study in awake volunteers.

Brain-Computer Interfaces (BCIs) have the potential to detect intraoperative awareness during general anaesthesia. Traditionally, BCI research is aimed at establishing or improving communication and control for patients with permanent paralysis. Patients experiencing intraoperative awareness also lack the means to communicate after administration of a neuromuscular blocker, but may attempt to move. This study evaluates the principle of detecting attempted movements from the electroencephalogram (EEG) during local temporary neuromuscular blockade. EEG was obtained from four healthy volunteers making 3-second hand movements, both before and after local administration of rocuronium in one isolated forearm. Using offline classification analysis we investigated whether the attempted movements the participants made during paralysis could be distinguished from the periods when they did not move or attempt to move. Attempted movement trials were correctly identified in 81 (68-94)% (mean (95% CI)) and 84 (74-93)% of the cases using 30 and 9 EEG channels, respectively. Similar accuracies were obtained when training the classifier on the participants' actual movements. These results provide proof of the principle that a BCI can detect movement attempts during neuromuscular blockade. Based on this, in the future a BCI may serve as a communication channel between a patient under general anaesthesia and the anaesthesiologist.

Different Approaches to Ultrasound-guided Thoracic Paravertebral Block: An Illustrated Review.

Given the fast development and increasing clinical relevance of ultrasound guidance for thoracic paravertebral blockade, this review article strives (1) to provide comprehensive information on thoracic paravertebral space anatomy, tailored to the needs of a regional anesthesia practitioner, (2) to interpret ultrasound images of the thoracic paravertebral space using cross-sectional anatomical images that are matched in location and plane, and (3) to briefly describe and discuss different ultrasound-guided approaches to thoracic paravertebral blockade. To illustrate the pertinent anatomy, high-resolution photographs of anatomical cross-sections are used. By using voxel anatomy, it is possible to visualize the needle pathway of different approaches in the same human specimen. This offers a unique presentation of this complex anatomical region and is inherently more realistic than anatomical drawings.

Prehospital administered fascia iliaca compartment block by emergency medical service nurses, a feasibility study.

INTRODUCTION: Patients with a proximal femur fracture are often difficult to evacuate from the accident scene. Prehospital pain management for this vulnerable group of patients may be challenging. Multiple co-morbidities, polypharmacy and increased age may limit the choice of suitable analgesics. The fascia iliaca compartment (FIC) block may be an alternative to intravenous analgesics. However this peripheral nerve block is mainly applied by physicians.In the Netherlands, prehospital emergency care is mostly provided by EMS-nurses. Therefore we examined whether well-trained EMS-nurses are able to successfully perform a FIC block in order to ensure timely and appropriate effective analgesia.The study was study was registered in the Netherlands Trial Register (NTR-nr 3824). METHODS: Ten EMS nurses were educated in the performance of a FIC-block. Indications, technique, side-effects and complications were discussed. Hereafter the trained EMS-nurses staffed ambulance teams were dispatched to patients with a suspicion for a proximal femur fracture. After confirmation of the diagnosis, the block was performed and 0.3 ml/kg lidocaine (10 mg/ml) with adrenaline 5 µg/ml was injected. The quality of pain relief, occurrence of complications and patient satisfaction were evaluated. RESULTS: In 108 patients a block was performed. One hundred patients could be included. Every EMS nurse performed at least 10 FIC blocks. The block was effective in 96 patients. The initial median (NRS)-pain score decreased after block performance to a score of 6 (after 10 minutes), 4 (after 20 minutes) and 3 (after 30 minutes). At arrival at the Emergency Department the median pain score was 3. Dynamic NRS-pain scores when transferring the patient from the accident scene to the ambulance stretcher, during transportation to the hospital and when transferring the patient to a hospital bed were, 4, 3 and 3.5 respectively. Patient satisfaction was very high. No complications were noted. CONCLUSION: Additional educated EMS-nurses are able to successfully perform a FIC-block for providing acute pain relief to patients with a suspected proximal femur fracture.

Combined EEG-fNIRS decoding of motor attempt and imagery for brain switch control: an offline study in patients with tetraplegia.

Combining electrophysiological and hemodynamic features is a novel approach for improving current performance of brain switches based on sensorimotor rhythms (SMR). This study was conducted with a dual purpose: to test the feasibility of using a combined electroencephalogram/functional near-infrared spectroscopy (EEG-fNIRS) SMR-based brain switch in patients with tetraplegia, and to examine the performance difference between motor imagery and motor attempt for this user group. A general improvement was found when using both EEG and fNIRS features for classification as compared to using the single-modality EEG classifier, with average classification rates of 79% for attempted movement and 70% for imagined movement. For the control group, rates of 87% and 79% were obtained, respectively, where the "attempted movement" condition was replaced with "actual movement." A combined EEG-fNIRS system might be especially beneficial for users who lack sufficient control of current EEG-based brain switches. The average classification performance in the patient group for attempted movement was significantly higher than for imagined movement using the EEG-only as well as the combined classifier, arguing for the case of a paradigm shift in current brain switch research.

The Episure Autodetect syringe, a loss-of-resistance technique for locating the epidural space, used in pediatric patients.

INTRODUCTION: The Episure Autodetect syringe, a spring-loaded syringe, is a loss-of-resistance syringe with an internal compression that applies constant pressure on the plunger. As the principle of loss-of-resistance is the same for adult and for pediatric patients, the Episure Autodetect syringe should be able to identify correctly the epidural space also in pediatric patients. METHODS: A retrospective review was carried out for all pediatric patients, in which the Episure Autodetect syringe was used for locating the epidural space between 2007 and 2011 in our department. RESULTS: In 17 pediatric patients (9 months-14 years, 7.5-43 kg weight), the Episure syringe was used. In all 17 patients, the epidural space was correctly identified using the spring-loaded syringe as evidenced by satisfactory analgesia. No accidental dural punctures or false loss-of-resistances were observed. CONCLUSION: The spring-loaded Episure Autodetect syringe might be a potentially useful loss-of-resistance syringe for identification of the epidural space in pediatric patients.