Sumatriptan for Postcraniotomy Headache after Minimally Invasive Craniotomy for Clipping of Aneurysms: A Prospective Randomized Controlled Trial.

Introduction Postcraniotomy headaches are often underestimated and undertreaded. This study aimed to identify if postoperative administration of sumatriptan after minimally invasive craniotomy for clipping an unruptured aneurysm could reduce postcraniotomy headache and improve the quality of postoperative recovery. Settings and Design Tertiary care center, single-center randomized double-blind placebo-controlled trial. Materials and Methods Patients who complained of postoperative headaches after minimally invasive craniotomy for clipping of unruptured aneurysms were randomized to receive subcutaneous sumatriptan (6 mg) or placebo. The primary outcome was the quality of recovery measured 24 hours after surgery. Secondary outcomes were total opioid use and headache score at 24 hours after surgery. Data were analyzed using a Student's t -test or the chi-square test. Results Forty patients were randomized to receive sumatriptan ( n = 19) or placebo ( n = 21). Both groups had similar demographics, comorbidities, and anesthesia management. The Quality of Recovery 40 score was higher for patients receiving sumatriptan compared to placebo, however, not statistically significant (173 [156-196] vs. 148 [139-181], p = 0.055). Postoperative opioid use between sumatriptan and placebo was lower, but not significant (5.4 vs. 5.6 mg morphine equivalent, p = 0.71). The severity of headache was also not statistically different between the two groups (5 [4-5] vs. 4 [2-5], p = 0.155). Conclusion In patients undergoing minimally invasive craniotomies for aneurysm clipping, sumatriptan given postoperatively has a nonsignificant trend for a higher quality of recovery. Similarly, there was a nonsignificant trend toward lower postcraniotomy headache scores and opioid scores for the patient given sumatriptan.

Emergency airway management in the prone position: an observational mannequin-based simulation study.

INTRODUCTION: Accidental extubation during prone position can be a life-threatening emergency requiring rapid establishment of the airway. However, there is limited evidence of the best airway rescue method for this potentially catastrophic emergency. The aim of this study was to determine the most effective method to recover the airway in case of accidental extubation during prone positioning by comparing three techniques (supraglottic airway, video laryngoscopy, and fiber-optic bronchoscopy) in a simulated environment. METHODS: Eleven anesthesiologists and 12 anesthesia fellows performed the simulated airway management using 3 different techniques on a mannequin positioned prone in head pins. Time required for definitive airway management and the success rates were measured. RESULTS: The success rates of airway rescue were 100% with the supraglottic airway device (SAD), 69.6% with the video laryngoscope (CMAC), and 91.3% with the FOB. The mean (SD) time to insertion was 18.1 (4.8) s for the supraglottic airway, 78.3 (32.0) s for the CMAC, and 57.3 (24.6) s for the FOB. There were significant differences in the time required for definitive airway management between the SAD and FOB (t = 5.79, p < 0.001, 95% CI = 25.92-52.38), the SAD and CMAC (t = 8.90, p < 0.001, 95% CI = 46.93-73.40), and the FOB and CMAC (t = 3.11, p = 0.003, 95% CI = 7.78-34.25). CONCLUSION: The results of this simulation-based study suggest that the SAD I-gel is the best technique to manage accidental extubation during prone position by establishing a temporary airway with excellent success rate and shorter procedure time. When comparing techniques for securing a definitive airway, the FOB was more successful than the CMAC.

Development of an Automated and Scalable Virtual Assistant to Aid in PPE Adherence: A Study with Implications for Applications within Anesthesiology.

Virtual assistants (VAs) are conversational agents that are able to provide cognitive aid. We developed a VA device for donning and doffing personal protective equipment (PPE) procedures and compared it to live human coaching to explore the feasibility of using VAs in the anesthesiology setting. An automated, scalable, voice-enabled VA was built using the Amazon Alexa device and Alexa Skills application. The device utilized voice-recognition technology to allow a touch-free interactive user experience. Audio and video step-by-step instructions for proper donning and doffing of PPE were programmed and displayed on an Echo Show device. The effectiveness of VA in aiding adherence to PPE protocols was compared to traditional human coaching in a randomized, controlled, single-blinded crossover design. 70 anesthesiologists, anesthesia assistants, respiratory therapists, and operating room nurses performed both donning and doffing procedures, once under step-by-step VA instructional guidance and once with human coaching. Performance was assessed using objective performance evaluation donning and doffing checklists. More participants in the VA group correctly performed the step of "Wash hands for 20 seconds" during both donning and doffing tests. Fewer participants in the VA group correctly performed the steps of "Put cap on and ensure covers hair and ears" and "Tie gown on back and around neck". The mean doffing total score was higher in the VA group; however, the donning score was similar in both groups. Our study demonstrates that it is feasible to use commercially available technology to create a voice-enabled VA that provides effective step-by-step instructions to healthcare professionals.

Preoperative Heart Rate Variability Predicts Postinduction Hypotension in Patients with Cervical Myelopathy: A Prospective Observational Study.

Background: Autonomic dysfunction, commonly seen in patients with cervical myelopathy, may lead to a decrease in blood pressure intraoperatively. Objective: The aim of our study is to determine if changes in Heart rate variability (HRV) could predict hypotension after induction of anesthesia in patients with cervical myelopathy undergoing spine surgery. Methods and Material: In this prospective observational study, 47 patients with cervical myelopathy were included. Five-minute resting ECG (5 lead) was recorded preoperatively and HRV of very low frequency (VLF), low frequency (LF), and high frequency (HF) spectra were calculated using frequency domain analysis. Incidence of hypotension (MAP <80 mmHg, lasting >5 min) and the number of interventions (40 mcg of phenylephrine or 5 mg of ephedrine) required to treat the hypotension during the period from induction to surgical incision were recorded. HRV indices were compared between the hypotension group and the stable group. Results: The incidence of hypotension after induction was 74.4% (35/47) and the median (IQR) interventions needed to treat hypotension was 2 (0.5-6). Patients who experienced hypotension had lower HF power and higher LF-HF ratios. A LF/HF >2.5 indicated postinduction hypotension likely. There was a correlation between increasing LF-HF ratio and the number of interventions that needs to maintain the MAP above 80 mmHg. Conclusion: HF power was lower and LF-HF ratio was higher in patients with cervical myelopathy who developed postinduction hypotension. Hence, preoperative HRV analysis can be useful to identify patients with cervical myelopathy who are at risk of post-induction hypotension.

Effect of reversal of residual neuromuscular blockade on the amplitude of motor evoked potentials: a randomized controlled crossover study comparing sugammadex and placebo.

PURPOSE: To compare the amplitude changes in motor evoked potentials (MEP) with reversal of residual neuromuscular blockade using sugammadex or placebo in patients with cervical myelopathy. METHODS: In this prospective randomized double-blind, placebo-controlled crossover trial, 38 patients with cervical myelopathy undergoing posterior cervical decompression and fusion were randomized to either sugammadex (2mg/kg) or placebo. The primary outcome measure was the increase in amplitude of the MEP in the first dorsal interossei (FDI) muscle at 3 min. Mann-Whitney U test was used to analyze the primary outcome measure. RESULTS: There was a significant increase in the amplitude of MEP at 3 min with sugammadex when compared to placebo group. The median (IQR) increase in MEP amplitude (µV) at 3 min from the left FDI in sugammadex and placebo group was 652.9 (142:1650) and 20.6 (-183.5:297.5) (p <0.001), respectively. Corresponding values from right FDI were 2153.4 (1400:4536.8) and 55(-65.2:480.8) (p=<0.001). CONCLUSION: Our study showed that there was a 200% increase in the MEP amplitude in the first dorsal interosseous muscle at 3 min following reversal of residual neuromuscular blockade with sugammadex. By ensuring that maximal MEP amplitude is recorded at baseline, early commencement of neuromonitoring can be achieved. TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION: The study was registered at http://clinicaltrials.gov , ID NCT03087513, Feb 5th 2018.

Airway Management with Leksell Frame in situ with or without Frontal Bar: A Mannequin Study.

BACKGROUND: The use of stereotactic headframes for neurosurgical procedures requiring targeted localization continues to grow with new advancements in technology and treatment modalities. A configuration of the Leksell stereotactic G frame with a straight front bar, useful in epilepsy and laser cases, almost completely obscures oral access and presents a significant airway challenge for the anesthetist. Although previous papers have suggested that the entire headframe should be removed during an airway emergency, we describe a novel method to remove only the front bar. METHODS: We performed an observational mannequin study. Anesthesia personnel from a single center were asked to intubate a mannequin with the Leksell frame fully in situ and again with the front bar removed. In addition, the time to remove the entire frame versus only the front bar was investigated. RESULTS: Eighteen anesthesia personnel participated in the study as well as four neurosurgeons. The average time to intubate the mannequin in the frame was 23.5 (11.4) seconds and with the front bar removed, 10.9 (2.5) seconds (p < 0.001). The average time taken to remove just the front bar by the neurosurgeons was 35.4 (7.3) seconds compared to an average of 83.3 (18.6) seconds to remove the headframe entirely (p < 0.001). CONCLUSION: Our study demonstrates that intubating with the Leksell front bar in situ is possible with videolaryngoscopy under an ideal situation. More importantly, the removal of just the front bar is a simpler more streamlined approach requiring statistically less time to secure an airway.

Effect of a neck collar on brain turgor: a potential role in preventing concussions?

BACKGROUND: Mild internal jugular vein (IJV) compression, aimed at increasing intracranial fluid volume to prevent motion of the brain relative to the skull, has reduced brain injury markers in athletes suffering repeated traumatic brain injuries. However, an increase in intracranial volume with IJV compression has not been well demonstrated. This study used transorbital ultrasound to identify changes in optic nerve sheath diameter (ONSD) as a direct marker of accompanying changes in intracranial volume. METHODS: Nineteen young, healthy adult volunteers (13 males and 6 females) underwent IJV compression of 20 cm H2O low in the neck, while in upright posture. IJV cross-sectional area at the level of the cricoid cartilage, and the change in right ONSD 3 mm behind the papillary segment of the optic nerve, were measured by ultrasound. Statistical analysis was performed using a paired t-test with Bonferroni correction. RESULTS: Mean (SD) cross-sectional area for the right IJV before and after IJV compression was 0.10 (0.05) cm2 and 0.57 (0.37) cm2, respectively (p=0.001). ONSD before and after IJV compression was 4.6 (0.5) mm and 4.9 (0.5) mm, respectively (p=0.001). CONCLUSIONS: These data verify increased cerebral volume following IJV compression, supporting the potential for reduced brain 'slosh' as a mechanism connecting IJV compression to possibly reducing traumatic brain injury following head trauma.

Anesthesia for deep brain stimulation: an update.

PURPOSE OF REVIEW: Deep brain stimulation (DBS) is a rapidly expanding surgical modality for the treatment of patients with movement disorders. Its ability to be adjusted, titrated, and optimized over time has given it a significant advantage over traditional more invasive surgical procedures. Therefore, the success and popularity of this procedure have led to the discovery of new indications and therapeutic targets as well as advances in surgical techniques. The aim of this review is to highlight the important updates in DBS surgery and to exam the anesthesiologist's role in providing optimal clinical management. RECENT FINDINGS: New therapeutic indications have a significant implication on perioperative anesthesia management. In addition, new technologies like frameless stereotaxy and intraoperative magnetic resonance imaging to guide electrode placement have altered the need for intraoperative neurophysiological monitoring and hence increased the use of general anesthesia. With an expanding number of patients undergoing DBS implantation, patients with preexisting DBS increasingly require anesthesia for unrelated surgery and the anesthesiologist must be aware of the considerations for perioperative management of these devices and potential complications. SUMMARY: DBS will continue to grow and evolve requiring adaptation and modification to the anesthetic management of these patients.

Opioid-sparing multimodal analgesia with bilateral bi-level erector spinae plane blocks in scoliosis surgery: a case report of two patients.

PURPOSE: Postoperative pain following scoliosis correction surgery is severe and usually requires prolonged intravenous opioid therapy. Regional anesthesia options are limited and include intrathecal opioid and epidural analgesia; however, they remain little used because of side effects and inconsistent efficacy. We describe a novel multimodal anesthetic regimen incorporating bilateral bi-level erector spinae plane (ESP) blocks together with a combination of several evidence-based intraoperative opioid-sparing analgesic strategies. METHODS: Two healthy young adult patients with idiopathic scoliosis underwent posterior spinal fusion involving 12 vertebral levels (T2-L1 and T3-L2). Bilateral single-injection ESP blocks were performed at two levels (T4 and T10) prior to incision. Intraoperatively, patients received intravenous dexamethasone and infusions of dexmedetomidine and ketamine for multimodal analgesia. Remifentanil was omitted from the total intravenous anesthetic regimen to avoid opioid-induced hyperalgesia. RESULTS: Both patients had minimal pain on emergence. They transitioned successfully to oral analgesia on the first postoperative day, with modest opioid requirements, no side effects, and low pain scores throughout their hospital stay. CONCLUSION: Bilateral bi-level ESP blocks are a simple method of providing pre-emptive regional analgesia in extensive multi-level spine surgery. Integration of ESP blocks into a multimodal regimen that employs other opioid-sparing strategies may have additive, and potentially synergistic, benefits in improving postoperative analgesia and reducing opioid requirements.

High-fidelity Training Model for Measurement of Dynamic Optic Nerve Sheath Diameter Using Transorbital Ultrasonography.

BACKGROUND: Transorbital ultrasonographic measurement of optic nerve sheath diameter (ONSD) is an important technique for bedside assessment of raised intracranial pressure (ICP). However, developing competency for this clinical skill requires practice scans on both normal subjects and patients with raised ICP. The aim of this study is to develop a high-fidelity training model capable of measuring dynamic changes in ONSD and to test the reliability and reproducibility of the model at different simulated ICP values. MATERIALS AND METHODS: We designed and developed a high-fidelity training model for dynamic ONSD measurement using a hemispherical table tennis ball, mounted on a 3.0-mm pediatric microcuffed endotracheal tube (ETT). Two independent investigators then performed a randomized blinded study to assess the reliability and reproducibility of the model. A total of 30 ONSD measurements (10 measurements each for 3 ETT cuff volumes of 0.1, 0.2, and 0.3 mL, simulating an ONSD of a normal, borderline, and raised ICP, respectively) were performed by each investigator. Intraclass correlation coefficients and Bland-Altman plots were calculated to analyze the level of agreement between the investigators. RESULTS: Our model was able to provide dynamic changes in ONSD secondary to ETT cuff volume changes. Small increments of 0.1 mL cuff volume changes produced immediate changes in ONSD that are similar to those observed in patients. The median interobserver difference in ONSD was 0.3 mm (interquartile range, 0. to 0.4 mm). Intraclass correlation coefficient was 0.89, 0.89, and 0.90 for 0.1, 0.2, and 0.3 mL ETT cuff volumes, respectively. CONCLUSIONS: We have developed a clinically relevant model capable of simulating changes in ONSD in patients with normal and raised ICP. This model could be a valuable training tool to gain scanning experience in optic nerve ultrasonography, and improve operators' technical abilities.

Efficiency and usability of a near field communication-enabled tablet for medication administration.

BACKGROUND: Barcode-based technology coupled with the electronic medication administration record (e-MAR) reduces medication errors and potential adverse drug events (ADEs). However, many current barcode-enabled medication administration (BCMA) systems are difficult to maneuver and often require multiple barcode scans. We developed a prototype, next generation near field communication-enabled medication administration (NFCMA) system using a tablet. OBJECTIVE: We compared the efficiency and usability of the prototype NFCMA system with the traditional BCMA system. METHODS: We used a mixed-methods design using a randomized observational cross-over study, a survey, and one-on-one interviews to compare the prototype NFCMA system with a traditional BCMA system. The study took place at an academic medical simulation center. Twenty nurses with BCMA experience participated in two simulated patient medication administration scenarios: one using the BCMA system, and the other using the prototype NFCMA system. We collected overall scenario completion time and number of medication scanning attempts per scenario, and compared those using paired t tests. We also collected participant feedback on the prototype NFCMA system using the modified International Business Machines (IBM) Post-Study System Usability Questionnaire (PSSUQ) and a semistructured interview. We performed descriptive statistics on participant characteristics and responses to the IBM PSSUQ. Interview data was analyzed using content analysis with a qualitative description approach to review and categorize feedback from participants. RESULTS: Mean total time to complete the scenarios using the NFCMA and the BCMA systems was 202 seconds and 182 seconds, respectively (P=.09). Mean scan attempts with the NFCMA was 7.6 attempts compared with 6.5 attempts with the BCMA system (P=.12). In the usability survey, 95% (19/20) of participants agreed that the prototype NFCMA system was easy to use and easy to learn, with a pleasant interface. Participants expressed interest in using the NFCMA tablet in the hospital; suggestions focused on implementation issues, such as storage of the mobile devices and infection control methods. CONCLUSIONS: The NFCMA system had similar efficiency to the BCMA system in a simulated scenario. The prototype NFCMA system was well received by nurses and offers promise to improve nurse medication administration efficiency.

Characteristic differences in the X-ray photoelectron spectrum between B-DNA and M-DNA monolayers on gold.

Duplex DNA monolayers were self-assembled on gold through a disulfide linkage and both B- and M-DNA conformations were studied using X-ray photoelectron spectroscopy (XPS). The film thickness, density, elemental composition and ratios for samples were analyzed and compared. The DNA surface coverage, calculated from both XPS and electrochemical measurements, was approximately 1.2 x 10(13)molecules/cm(2) for B-DNA. All samples showed distinct peaks for C 1s, O 1s, N 1s, P 2p and S 2p as expected for a thiol-linked DNA. On addition of Zn(2+) to form M-DNA the C 1s, P 2p and S 2p showed only small changes while both the N 1s and O 1s spectra changed considerably. This result is consistent with Zn(2+) interacting with oxygen on the phosphate backbone as well as replacing the imino protons of thymine (T) and guanine (G) in M-DNA. Analysis of the Zn 2p spectra also demonstrated that the concentration of Zn(2+) present under M-DNA conditions is consistent with Zn(2+) binding to both the phosphate backbone as well as replacing the imino protons of T or G in each base pair. After the M-DNA monolayer is washed with a buffer containing only Na(+) the Zn(2+) bound to the phosphate backbone is removed while the Zn(2+) bound internally still remains.

An analysis of mismatched duplex DNA unzipping through a bacterial nanopore.

A 50-base Guide strand was synthesized that consisted of a central 10-base probe sequence flanked by two tracts of 20 adenine residues. Target sequences of 10 bases containing up to three mismatches were prepared and hybridized to the Guide strand in 1 M KCl. The transport of these constructs through single alpha-hemolysin pores was analysed by measuring the current blockade as a function of time. Complementary dsDNA takes significantly longer (840 +/- 60 micro s) to pass through the pore than a sequence of the same length containing a single (590 +/- 45 micro s) and a double (270 +/- 50 micro s) mismatch. Constructs involving three mismatches were indistinguishable from Guide ssDNA transport (120 +/- 30 micro s). The results suggest that dsDNA must unzip as it is transported through the nanopore. Duplexes containing mismatches unzip more quickly and can be distinguished from those with perfect complementarity.

Overexpression of L-isoaspartate O-methyltransferase in Escherichia coli increases heat shock survival by a mechanism independent of methyltransferase activity.

Over time and under stressing conditions proteins are susceptible to a variety of spontaneous covalent modifications. One of the more commonly occurring types of protein damage is deamidation; the conversion of asparagines into aspartyls and isoaspartyls. The physiological significance of isoaspartyl formation is emphasized by the presence of the conserved enzyme L-isoaspartyl O-methyltransferase (PIMT), whose physiological function appears to be in preventing the accumulation of deamidated proteins. Seemingly consistent with a repair function, overexpression of PIMT in Drosophila melanogaster extends lifespan under conditions expected to contribute to protein damage. Based on structural information and sequence homology we have created mutants of residues proposed to be involved in co-factor binding in Escherichia coli PIMT. Both mutants retain S-adenosyl L-methionine binding capabilities but demonstrate dramatically reduced kinetic capabilities, perhaps suggestive of catalytic roles beyond co-factor binding. As anticipated, overexpression of the wild type enzyme in E. coli results in bacteria with increased tolerance to thermal stress. Surprisingly, even greater levels of heat tolerance were observed with overexpression of the inactive PIMT mutants. The increased survival capabilities observed with overexpression of PIMT in E. coli, and possibly in Drosophila, are not due to increased isoaspartyl repair capabilities but rather a temperature-independent induction of the heat shock system as a result of overexpression of a misfolding-prone protein. An alternate hypothesis as to the physiological substrate and function of L-isoaspartyl methyltransferase is proposed.

M-DNA is stabilised in G*C tracts or by incorporation of 5-fluorouracil.

M-DNA is a complex between the divalent metal ions Zn2+, Ni2+ and Co2+ and duplex DNA which forms at a pH of approximately 8.5. The stability and formation of M-DNA was monitored with an ethidium fluorescence assay in order to assess the relationship between pH, metal ion concentration, DNA concentration and the base composition. The dismutation of calf thymus DNA exhibits hysteresis with the formation of M-DNA occurring at a higher pH than the reconversion of M-DNA back to B-DNA. Hysteresis is most prominent with the Ni form of M-DNA where complete reconversion to B-DNA takes several hours even in the presence of EDTA. Increasing the DNA concentration leads to an increase in the metal ion concentration required for M-DNA formation. Both poly(dG)*poly(dC) and poly(dA)*poly(dT) formed M-DNA more readily than the corresponding mixed sequence DNAs. For poly(dG)*(poly(dC) M-DNA formation was observed at pH 7.4 with 0.5 mM ZnCl2. Modified bases were incorporated into a 500 bp fragment of phage lambda DNA by polymerase chain reaction. DNAs in which guanine was replaced with hypoxanthine or thymine with 5-fluorouracil formed M-DNA at pHs below 8 whereas substitutions such as 2-aminoadenine and 5-methylcytosine had little effect. Poly[d(A5FU)] also formed a very stable M-DNA duplex as judged from T(m) measurements. It is evident that the lower the pK(a) of the imino proton of the base, the lower the pH at which M-DNA will form; a finding that is consistent with the replacement of the imino proton with the metal ion.