ISRN Anesthesiology The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Propofol Protects against Ischemia/Reperfusion Injury Associated with Reduced Apoptosis in Rat Liver Sat, 24 Aug 2013 09:21:18 +0000 Propofol is an intravenous anesthetic, reported to have a protective effect against ischemia/reperfusion (I/R) injury in heart and brain, but no definite data are available concerning its effect in hepatic I/R. This work investigated the effect of propofol anesthesia on hepatic I/R injury using in vivo rat model. Four groups of rats were included: sham operated, I/R (30 min ischemia and 2 h reperfusion), I/R treated with propofol (10 mg/kg/h), and I/R treated with propofol (20 mg/kg/h). Liver enzyme leakage, TNF-α and caspase-3 levels, and antiapoptotic Bcl-xL/apoptotic Bax gene expression, together with histopathological changes, were used to evaluate the extent of hepatic I/R injury. Compared with sham-operated group, I/R group showed significant increase in serum levels of liver enzymes (ALT, AST), TNF-α, and caspase-3 and significant decrease in the Bcl-xL/Bax ratio, associated with histopathologic damage in liver. Propofol infusion significantly attenuated these changes with reduced hepatic histopathologic lesions compared with nonpreconditioned I/R group. However, no significant differences were found between two groups treated with different doses of propofol. In conclusion, propofol infusion reduced hepatic I/R injury with decreased markers of cellular apoptosis. Therefore, propofol anesthesia may provide a useful hepatic protection during liver surgery. Ali F. Abdel-Wahab and Wahid M. Al-Harizy Copyright © 2013 Ali F. Abdel-Wahab and Wahid M. Al-Harizy. All rights reserved. Anesthetic Management in Mucopolysaccharidoses Tue, 04 Jun 2013 15:08:22 +0000 Mucopolysaccharidoses (MPSs) are a group of uncommon genetic diseases of connective tissue metabolism. It is well established that the elective treatment of subjects affected by MPS is multidisciplinary and must be carried out by experienced personnel in highly specialist centers. However, there is the possibility to perform an anesthesia in a peripheral center, where anesthesiologists might not have a large experience of MPS. Various attempts to produce guidelines have been made for MPS. There has been an increasing interest in the topic as it is demonstrated by the number of scientific studies published in the last few years (peak in 2011). We want to provide a summary of anesthetic management, reviewing the current literature on the topic in a procedural algorithm for these high-risk patients, who require surgical procedures and diagnostic examinations under sedation with a higher frequency than the general population. Concetta Maria Spinello, Lorena Maria Novello, Sofia Pitino, Claudia Raiti, Paolo Murabito, Fortunato Stimoli, and Marinella Astuto Copyright © 2013 Concetta Maria Spinello et al. All rights reserved. Effect of Two Different Doses of Gabapentin on the Intraocular Pressure and Hemodynamic Stress Responses to Laryngoscopy and Tracheal Intubation Tue, 05 Mar 2013 13:46:18 +0000 Background. The stress response to laryngoscopy and intubation causes an undesirable increase in heart rate, blood pressure, and intraocular pressure. This study was designed to compare the effect of two doses of gabapentin on the stress response to laryngoscopy and intubation. Patients and Methods. (ASA I and II) 60 patients, aged from 18 to 60 years undergoing elective eye surgery requiring endotracheal intubation, were randomly allocated into 3 groups, 20 patients each. 2 hours before the surgery, group I received oral placebo, and groups II and III received oral gabapentin 800 mg and 1200 mg, respectively. Heart rate (HR), mean arterial pressure (MAP), and intraocular pressure (IOP) were measured before and after induction of anesthesia, immediately after, 5 minutes, and 10 minutes after intubation. Results. Gabapentin 1200 mg prevented the increase in HR, MAP, and IOP, secondary to laryngoscopy and intubation, and kept them below the baseline till 10 minutes after intubation (), while with gabapentin 800 mg, the increase in HR, MAP, and IOP was nonsignificant () and returned to levels below the baseline at 5 and 10 minutes after intubation. Conclusion. Preoperative gabapentin 1200 mg effectively prevented the stress response to laryngoscopy and intubation; meanwhile, gabapentin 800 mg only prevented significant stress response. Amani A. Ali, Abeer M. Elnakera, and Ahmed Samir Copyright © 2013 Amani A. Ali et al. All rights reserved. Midazolam in Subarachnoid Block: Current Evidence Wed, 27 Feb 2013 11:09:47 +0000 Midazolam, despite of being the commonest benzodiazepine used in anaesthesia and perioperative care, is a relatively newer addition to the list of adjuvant used in subarachnoid block. Midazolam causes spinally mediated analgesia and the segmental analgesia produced by intrathecal midazolam is mediated by the benzodiazepine-GABA receptor complex. Initial animal studies questioned the safety of intrathecal midazolam in terms of possible neurotoxicity. However subsequent clinical studies also failed to show any neurotoxicity of high dose midazolam even on long-term use. Addition of intrathecal midazolam to bupivacaine significantly improves the duration and quality of spinal anaesthesia and provides prolonged perioperative analgesia without any significant side effects. Clinical studies also reported its safety and efficacy in pregnant women, but some studies also reported mild sedation with intrathecal midazolam. It is also reported to decrease the incidence of PONV. Intrathecal midazolam does not have any clinically significant effect on perioperative hemodynamics. Anirban Chattopadhyay, Souvik Maitra, and Suvadeep Sen Copyright © 2013 Anirban Chattopadhyay et al. All rights reserved. Pharmacoeconomics and Pharmacodynamic Interactions of Rocuronium and Pancuronium Mon, 25 Feb 2013 14:25:47 +0000 Background. We evaluated the pharmacodynamic interaction of the combination of pancuronium and Rocuronium by analyzing time-response relationship, quality of intubating conditions, changes in the hemodynamics, and cost effectiveness as compared to individual drugs. Methods. Sixty patients in the ASA-I category received either 10 ml of 0.9 mg/kg rocuronium (R) plus 10 ml of saline or 10 ml of 0.1 mg/kg pancuronium (P) plus 10 ml of saline or a combination (C) of 10 ml of 0.45 mg/kg R plus 10 ml of 0.05 mg/kg P according to randomization list. Neuromuscular function was measured up to maximal suppression of twitch height. Results. The mean times (sec) taken for twitch height to decrease to 50% of baseline in R, P, and C were , , and , respectively. The mean cost of intubation per patient was INR in group R, INR in group P, and INR in group C. Conclusions. The combination of P and R provides rapid and smooth intubation with minimal hemodynamic changes at a reasonably priced cost. HariSrinivas Shyam Kumar, Padmaja Durga, Rama Mohan Pathapati, Sujith Tumkur Rajashekar, Pothula Narasimha Reddy, and Gopinath Ramachandran Copyright © 2013 HariSrinivas Shyam Kumar et al. All rights reserved. Comparative Effects of Single Shot Intrathecal Bupivacaine with Dexmedetomidine and Bupivacaine with Fentanyl on Labor Outcome Thu, 20 Dec 2012 13:54:12 +0000 Background. Effective intrapartum analgesia attenuates pain, stress, and anxiety which cause release of stress hormones as well as beta-endorphins. Aim. The purpose of this study was to determine the effect of adding dexmedetomidine to hyperbaric bupivacaine for neuraxial analgesia for labor. Methods. Ninety laboring multiparous women were allocated to have single shot intrathecal bupivacaine alone (B), bupivacaine with fentanyl (BF), or bupivacaine with dexmedetomidine (BD). Sensory and motor block characteristics; time from injection to two dermatome sensory regression, sensory regression to S1 dermatome, and motor block regression to Bromage 1 were recorded. Labor pain was assessed with a 10 cm verbal pain scale. Results. Peak sensory block levels in the three groups were essentially the same (). The time for sensory and motor blocks to reach T10 dermatome and Bromage 1, respectively, was faster in group BD than in the other groups (). The time for sensory regression to S1 was significantly prolonged in the group BD (). Motor block regression time to Bromage 1 was also prolonged in the group BD (). Neonatal outcome was normal in all groups. Conclusion. Single shot intrathecal bupivacaine/dexmedetomidine significantly prolonged sensory block in laboring women. S. Fyneface-Ogan, O. Gogo Job, and C. E. Enyindah Copyright © 2012 S. Fyneface-Ogan et al. All rights reserved. Utilization of a Swine (Sus scrofa) Model for Lipid Emulsion Resuscitation Studies Tue, 04 Dec 2012 15:21:17 +0000 Background. There have been some discussions that using swine or rabbits in a resuscitation model to study lipid emulsion infusions may be inappropriate because of a consistent “pseudoallergic” reaction that has been found in lipid-based nanoparticle liposome drug carrier systems. Assertions have been made that the lipid emulsions may contain a certain amount of liposomes; therefore swine may not be an appropriate model for study. Methods. This study was prospective, crossover design within subjects, and research design with each Yorkshire swine receiving a 20% lipid bolus infusion followed by a lipid infusion for 10 min. Each swine had a total of four blood draws and each draw had complete blood gas analysis with three different types of inflammatory markers examined. Cardio vascular monitoring was performed every 2 minutes. Results. Using data reported in similar studies, a large effect size of 0.6 was calculated. Using the effect size of 0.6, a power of 0.8 and an alpha of 0.05 it was determined that a sample size of five swine was needed. There were no significant changes in any CV parameter both before and after lipid emulsion. Likewise there were no significant changes in any of the blood tests, nor any inflammatory markers. Conclusions. There were no significant changes in the examined parameters with swine before and after lipid emulsion infusions. It is suggested that due to the close size of swine to humans, similar physiology, and ease of using these animals, they may be utilized for lipid emulsion studies. Carrie Crane, Eileen Sagini, Arthur D. Johnson, and Joseph O'Sullivan Copyright © 2012 Carrie Crane et al. All rights reserved. Evaluation of Airway Scope at Improving the Success Rate of the First Intubation Attempt by Nonexpert Physicians: A Randomized Crossover Manikin Study Tue, 20 Nov 2012 09:46:13 +0000 Purpose. The aim of the study was to assess the performance of Airway Scope (AWS) on the first attempt at intubation in manikins by nonexpert physicians. Methods. A randomized crossover trial involving seven scenarios. Participants: residents of a cardiovascular hospital. In group A, the AWS procedure was performed first followed by Machintouch Laryngoscopy (ML), while in group B the ML procedure was performed first and then the AWS. The primary outcome assessed was the success of first intubation attempt in a normal scenario. The secondary outcome assessments were success in six other scenarios, and also elapsed time and dental trauma caused in all scenarios. Results. There were 34 participants. All AWS-assisted intubations were successfully completed, but one ML-assisted intubation failed in the normal scenario (). The outcomes achieved by the AWS in scenarios involving cervical immobilization (), tongue edema (), pharyngeal obstruction (), and jaw trismus () were superior to those obtained with the ML. Conclusions. Use of AWS-assisted intubation in manikin scenarios results in a significantly high intubation success rate on the first attempt by nonexpert physicians. These findings suggest this new device will be useful for nonexpert physicians in emergency situations. Haruyuki Yuasa, Hiroyuki Yokoyama, Naohiro Yonemoto, Yoichiro Kasahara, and Hiroshi Nonogi Copyright © 2012 Haruyuki Yuasa et al. All rights reserved. MicroPET/CT Imaging of [18F]-FEPPA in the Nonhuman Primate: A Potential Biomarker of Pathogenic Processes Associated with Anesthetic-Induced Neurotoxicity Mon, 05 Nov 2012 10:14:05 +0000 Background. The inhalation anesthetics nitrous oxide (N2O) and isoflurane (ISO) are used in surgical procedures for human infants. Injury to the central nervous system is often accompanied by localization of activated microglia or astrocytosis at the site of injury. The tracer that targets to the peripheral benzodiazepine receptor (PBR), [18F]N-2-(2-fluoroethoxy)benzyl)-N-(4-phenoxypyridin-3-yl)acetamide ([18F]-FEPPA), has been reported as a sensitive biomarker for the detection of neuronal damage/inflammation. Methods. On postnatal day (PND) 5 or 6 rhesus monkey neonates were exposed to a mixture of N2O/oxygen and ISO for 8 hours and control monkeys were exposed to room air. MicroPET/CT images with [18F]-FEPPA were obtained for each monkey 1 day, one week, three weeks, and 6 months after the anesthetic exposure. Results. The radiotracer quickly distributed into the brains of both treated and control monkeys on all scan days. One day after anesthetic exposure, the uptake of [18F]-FEPPA was significantly increased in the temporal lobe. One week after exposure, the uptake of [18F]-FEPPA in the frontal lobe of treated animals was significantly greater than that in controls. Conclusions. These findings suggest that microPET imaging is capable of dynamic detection of inhaled anesthetic-induced brain damage in different brain regions of the nonhuman primate. Xuan Zhang, Merle G. Paule, Glenn D. Newport, Fang Liu, Ralph Callicott, Shuliang Liu, Marc S. Berridge, Scott M. Apana, William Slikker Jr., and Cheng Wang Copyright © 2012 Xuan Zhang et al. All rights reserved. Isoflurane Enhances the Moonlighting Activity of GAPDH: Implications for GABAA Receptor Trafficking Wed, 17 Oct 2012 17:03:57 +0000 receptor activity is directly modulated by glyceraldehyde 3-phosphate dehydrogenase (GAPDH), a protein with many nonglycolytic moonlighting functions. In addition to playing a role in the phosphorylation of the receptor, GAPDH may also participate in proper receptor trafficking to the plasma membrane. We previously showed that volatile anesthetics affect GAPDH structure and function that may contribute to the manner by which GAPDH modulates the receptor. In the current study, GAPDH interacted with engineered phospholipid-containing vesicles, preferring association with phosphatidylserine over phosphatidylcholine. Phosphatidyl-serine is known to participate in membrane trafficking of transport proteins and to play a role in receptor stability and function. We observed that GAPDH promoted the self-association and fusion of phosphatidyl-serine-rich vesicles as well as decreased membrane fluidity. Isoflurane enhanced each of these GAPDH-mediated events. Isoflurane also increased the binding of GAPDH to the cytoplasmic loop of the receptor. These observations are consistent with the working model of isoflurane playing a role in the trafficking of membrane proteins. This study is the first to implicate GAPDH and isoflurane in the regulation of receptor localization, providing insight into the mechanism of action of anesthesia. Andrew J. Montalbano, Christopher S. Theisen, Eugene E. Fibuch, and Norbert W. Seidler Copyright © 2012 Andrew J. Montalbano et al. All rights reserved. Inferior Hypogastric Plexus Block Affects Sacral Nerves and the Superior Hypogastric Plexus Sat, 29 Sep 2012 12:02:32 +0000 Background. The inferior hypogastric plexus mediates pain sensation through the sympathetic chain for the lower abdominal and pelvic viscera and is thought to be a major structure involved in numerous pelvic and perineal pain syndromes and conditions. Objectives. The objective of this study was to demonstrate the structures affected by an inferior hypogastric plexus blockade utilizing the transsacral approach. Study Design. This is an observational study of fresh cadaver subjects. Setting. The cadaver injections and dissections were performed at the Department of Forensic Sciences and Insurance Medicine, Semmelweis University, Budapest, Hungary after obtaining institutional review board approval. Methods. 5 fresh cadavers underwent inferior hypogastric plexus blockade with radiographic contrast and methylene blue dye injection by the transsacral fluoroscopic technique described by Schultz followed by dissection of the pelvic and perineal structures to localize distribution of the indicator dye. Radiographs demonstrating correct needle localization by contrast spread in the specific tissue plane and photographs of the dye distribution after cadaver dissection were recorded for each subject. Results. In all cadavers the dye spread to the posterior surface of the rectum and the superior hypogastric plexus. The dye also demonstrated distribution to the anterior sacral nerve roots of S1, 2, and 3 with bilateral spread in 3 cadavers and ipsilateral spread in 2 of them. Limitations. The small number of cadaver specimens in this study limits the results and generalization of their clinical significance. Conclusions. Inferior hypogastric plexus blockade by a transsacral approach results in distribution of dye to the anterior sacral nerve roots and superior hypogastric plexus as demonstrated by dye spread in freshly dissected cadavers and not by local anesthetic spread to other pelvic and perineal viscera. A. Stogicza, A. M. Trescot, E. Racz, L. Lollo, L. Magyar, and E. Keller Copyright © 2012 A. Stogicza et al. All rights reserved. Applications of Steroid in Clinical Practice: A Review Thu, 27 Sep 2012 09:57:21 +0000 Steroids are perhaps one of the most widely used group of drugs in present day anaesthetic practice, sometimes with indication and sometimes without indications. Because of their diverse effects on various systems of the body, there has been renewed interest in the use of steroids in modern day anaesthetic practice. This paper focuses on the synthesis and functions of steroids and risks associated with their supplementation. This paper also highlights the recent trends, relevance, and consensus issues on the use of steroids as adjunct pharmacological agents in relation to anaesthetic practice and intensive care, along with emphasis on important clinical aspects of perioperative usefulness and supplementation. Safiya Shaikh, Himanshu Verma, Nirmal Yadav, Mirinda Jauhari, and Jyothi Bullangowda Copyright © 2012 Safiya Shaikh et al. All rights reserved. Emergence from Anaesthesia in Supine versus Prone Position in Patients Undergoing Lumbar Laminectomy: A Study of 60 Cases Thu, 30 Aug 2012 11:01:17 +0000 Background. Emergence in supine position in patients undergoing surgery in prone position leads to tachycardia and hypertension, coughing, and the loss of monitoring when patients are rolled to supine position at the end of surgery, aim of this prospective randomized trial was to study whether prone emergence causes less hemodynamic stimulation, coughing, and monitor disconnection compared to supine emergence in patients undergoing lumbar laminectomy. Patients and Methods. This study was conducted on 60 patients who underwent Lumbar laminectomy in prone position. Patients were anaesthetized using injected fentanyl 2 μg kg−1, midazolam 0.1 mg kg−1, and thiopentone 5–6 mg kg−1 and vecuronium bromide. At the end of surgery patients were randomized into prone or supine group of 30 each. Supine group patients were rolled back and prone were left undisturbed. Extubation was done after complete reversal of neuromuscular block. Heart rates and MAP were noted at various points of time. Coughing, vomiting, monitor disconnection if any. Results. Mean arterial pressure and heart rate were significantly higher in supine patients as compared to prone patients before and after extubation (P value < 0.05). Incidence of coughing, vomiting and monitor disconnection was highly significant in prone group than in supine group. Conclusion. Emergence and extubation in prone position can be safely performed in selected group of patients undergoing surgery in prone position. Priyanka Goyal, Manda Nagrale, and Sandeep Joshi Copyright © 2012 Priyanka Goyal et al. All rights reserved. Reduction of Oxygen-Carrying Capacity Weakens the Effects of Increased Plasma Viscosity on Cardiac Performance in Anesthetized Hemodilution Model Thu, 19 Jul 2012 08:21:10 +0000 We investigated the effects of reduced oxygen-carrying capacity on cardiac function during acute hemodilution, while the plasma viscosity was increased in anesthetized animals. Two levels of oxygen-carrying capacity were created by 1-step and 2-step hemodilution in male golden Syrian hamsters. In the 1-step hemodilution (1-HD), 40% of the animals' blood volume (BV) was exchanged with 6% dextran 70 kDa (Dx70) or dextran 2000 kDa (Dx2M). In the 2-step hemodilution (2-HD), 25% of the animals' BV was exchanged with Dx70 followed by 40% BV exchanged with Dx70 or Dx2M after 30 minutes of first hemodilution. Oxygen delivery in the 2-HD group consequently decreased by 17% and 38% compared to that in the 1-HD group hemodiluted with Dx70 and Dx2M, respectively. End-systolic pressure and maximum rate of pressure change in the 2-HD group significantly lowered compared with that in the 1-HD group for both Dx70 and Dx2M. Cardiac output in the 2-HD group hemodiluted with Dx2M was significantly higher compared with that hemodiluted with Dx70. In conclusion, increasing plasma viscosity associated with lowering oxygen-carrying capacity should be considerably balanced to maintain the cardiac performance, especially in the state of anesthesia. Surapong Chatpun and Pedro Cabrales Copyright © 2012 Surapong Chatpun and Pedro Cabrales. All rights reserved. Ultrasound-Guided Regional Anaesthesia in the Paediatric Population Mon, 18 Jun 2012 10:11:01 +0000 Ultrasound-guided regional anaesthesia is rapidly growing in popularity. Initially, most evidence was for the benefits when used in adults, but there is now a multitude of well-documented benefits in children. The practice of regional anaesthesia in children differs somewhat from that of adults in that in the majority of cases it is used for analgesia and performed under general anaesthesia to allow placement, rather than alone for anaesthesia as in adults. The purpose of this paper is to review the basic aspects of ultrasound regional anaesthesia before going into detail regarding specific techniques. Catherine Gerrard and Steve Roberts Copyright © 2012 Catherine Gerrard and Steve Roberts. All rights reserved. Blood Loss and Massive Transfusion in Patients Undergoing Major Oncological Surgery: What Do We Know? Sun, 13 May 2012 14:03:42 +0000 Patients with solid malignancies who were not candidates for tumor resections in the past are now presenting for extensive oncological resections. Cancer patients are at risk for thromboembolic complications due to an underlying hypercoagulable state; however, some patients may have an increased risk for bleeding due to the effects of chemotherapy, the administration of anticoagulant drugs, tumor-related fibrinolysis, tumor location, tumor vascularity, and extent of disease. A common potential complication of all complex oncological surgeries is massive intra- and postoperative hemorrhage and the subsequent risk for massive blood transfusion. This can be anticipated or unexpected. Several surgical and anesthesia interventions including preoperative tumor embolization, major vessel occlusion, hemodynamic manipulation, and perioperative antifibrinolytic therapy have been used to prevent or control blood loss with varying success. The exact incidence of massive blood transfusion in oncological surgery is largely unknown and/or underreported. The current literature mostly consists of purely descriptive observational studies. Thus, recommendation regarding specific perioperative intervention cannot be made at this point, and more research is warranted. Juan P. Cata and Vijaya Gottumukkala Copyright © 2012 Juan P. Cata and Vijaya Gottumukkala. All rights reserved. Research and Scholarly Activity in US Anesthesiology Residencies: A Survey of Program Directors and Residents Thu, 12 Apr 2012 10:43:51 +0000 Background. Effective 2007, the ACGME required scholarly activity during residency. Although many programs have ongoing research, residents' involvement may be limited. This US anesthesiology residency survey assesses the current scholarly environment, research activity and program support during training. Methods. Following IRB approval, 131 US anesthesiology program directors were invited to participate in a web-based survey. Questions to directors and residents included program structure, research activity, funding and productivity. We categorized residencies threefold based on their size. Results are summarized descriptively. Results. The response rate was 31.3% (𝑛=41) for program directors and 15.3% (𝑛=185) for residents. Residents' responses mirrored those of program directors' regarding the presence of didactic curricula (51% versus 51.9%), research rotations (57% versus 56.2%) and a project requirement (37% versus 40%). Demands of residency (27.0%) and early stage in training (22.2%) were the main obstacles to research cited by trainees. Residents' financial support was available in 94.3% of programs. Medium and large programs had multiple funding sources (NIH, industrial and private). Conclusion. Programs are dedicated to incorporate research into their curriculum. Residents' financial support and mentorship are available, while research time is limited. Systematic improvements are needed to increase trainee research in US anesthesiology residencies. Viviane G. Nasr, Iqbal Ahmed, Iwona Bonney, and Roman Schumann Copyright © 2012 Viviane G. Nasr et al. All rights reserved. Medial Approach to the Sciatic Nerve at the Popliteal Fossa in the Supine Position with Ultrasound Guidance and Nerve Stimulator Thu, 29 Mar 2012 11:15:49 +0000 Ultrasound guided sciatic nerve block (SNB) at the popliteal fossa is performed with the lateral approach in the supine position or with the lateral or posterior approach in the prone position. When the sciatic nerve (SN) is blocked with the lateral approach in the supine position, the lower limb must be sufficiently elevated to enable adequate space around the knee joint for transducer application. When the SN is blocked in the prone position, the patients’ position needs to be changed. We report a medial approach to the SNB at the popliteal fossa in the supine position with ultrasound guidance. Ten patients scheduled for elective knee or foot surgery participated in this study. Patients were placed in the supine position, with the hip and knee on the operated side flexed and the thigh externally rotated at approximately 45 degrees. A block needle was inserted in-plane with the transducer toward the SN bifurcation from the medial side of the thigh. The block performance time for SNB was 1.8Β±0.5 min (1.3–3.1 min). All blocks were effective. Our medial approach to the SN in the supine position with ultrasound guidance does not require elevation of the patient’s lower limb or a change in the patient’s position. Tomoaki Yanaru, Kenji Shigematsu, Kazuo Higa, Erisa Nakamori, and Keiichi Nitahara Copyright © 2012 Tomoaki Yanaru et al. All rights reserved. Mechanism of Anesthetic Toxicity: Metabolism, Reactive Oxygen Species, Oxidative Stress, and Electron Transfer Tue, 17 Jan 2012 10:54:03 +0000 There is much literature on the toxic effects of anesthetics. This paper deals with both the volatiles and locals. Adverse effects appear to be multifaceted, with the focus on radicals, oxidative stress (OS), and electron transfer (ET). ET functionalities involved are quinone, iminoquinone, conjugated iminium, and nitrone. The non-ET routes involving radicals and OS apparently pertain to haloalkanes and ethers. Beneficial effects of antioxidants, evidently countering OS, are reported. Knowledge at the molecular level should aid in devising strategies to combat the adverse effects. Peter Kovacic and Ratnasamy Somanathan Copyright © 2011 Peter Kovacic and Ratnasamy Somanathan. All rights reserved. Diagnostic Potential of Distortion Product Otoacoustic Emissions in Noninvasive Assessment of Elevated Intracranial Pressure: Different Patterns of DPOAE Alterations in the Guinea Pig Wed, 28 Dec 2011 08:58:37 +0000 Distortion product otoacoustic emissions (DPOAEs) have been proposed for monitoring the intracranial pressure (ICP) noninvasively. Aim of this study was to establish an animal model in the guinea pig for a detailed characterisation of ICP-related DPOAE alterations. In guinea pigs, the ICP was elevated experimentally and the DPOAE levels were continuously monitored. Two different patterns of DPOAE level changes were observed: (1) a decrease of few decibels affecting mainly the frequency 𝑓2 = 2 kHz with instant recovery after normalization of ICP, probably related to alterations of middle ear sound transmission; (2) a more pronounced level decrease affecting all frequencies, combined with a second decrease and prolonged recovery after ICP normalization, which might be related to alterations of the cochlear blood flow. Alterations of the levels of DPOAEs might not only provide information about ICP but also indicate critical ICP-induced reductions of the cochlear and the cerebral perfusion pressure. Ulrich Strassen, Christoph Deppe, Klaus Mees, Nikolaus Plesnila, Martin Canis, Sebastian Strieth, and Bernhard Olzowy Copyright © 2011 Ulrich Strassen et al. All rights reserved. Xenon Upregulates Hypoxia Inducible Factor 1 Alpha in Neonatal Rat Brain under Normoxic Conditions Sun, 25 Dec 2011 14:32:32 +0000 Xenon can induce cell and organ protection through different molecular mechanisms related to oxygen level. We explored the effect of xenon on oxygen-related signalling in the central nervous system via hypoxia inducible factor 1 alpha (HIF-1α) and mammalian target of rapamycin (mTOR). Methods. Postnatal day 7 (P7) Sprague Dawley rats were exposed to 25% oxygen/75% nitrogen (air group) or 25% oxygen/75% xenon (treatment group) for 120 min. Brains were collected immediately (transcript analysis—relative real-time polymerase chain reaction) or 24 hours (protein analysis—immunohistochemistry) after the 120-minute exposure period; peak anesthetic preconditioning has been previously identified at 24 hours post-exposure. Results. HIF-1α transcript and protein levels were found to be increased in xenon-exposed compared to air-exposed brains. Sustained nuclear translocation of the protein, accounting for an increased activity of HIF-1α, was also noted. mTOR transcript analysis revealed no significant difference between xenon-exposed and air-exposed brains immediately after the 120-minute exposure. Conclusion. Our data suggest that xenon induces the upregulation of HIF-1α transcription and translation, which may contribute to xenon's neuroprotective preconditioning effect. However, given that xenon exposure did not affect mTOR transcription, further investigation into other signalling cascades mediating xenon’s effects on HIF-1α in developing brain is warranted. Simona Valleggi, Chirag B. Patel, Andrea O. Cavazzana, Daqing Ma, Francesco Giunta, and Davide Cattano Copyright © 2011 Simona Valleggi et al. All rights reserved. Comparison of the Neuromuscular Profile of the First Dorsal Interosseous Muscle and the Flexor Hallucis Brevis Muscle as Measured by Electromyography Thu, 22 Dec 2011 11:56:28 +0000 Lower limb muscles recover faster than upper limb muscles following administration of nondepolarizing neuromuscular relaxants until the train-of-four ratio (TOFR) reached 0.7. However, no study has been conducted to evaluate the recovery time of the flexor hallucis brevis muscle (FHBM), up to a TOFR of 0.9, which indicates satisfactory recovery of neuromuscular blockade. The aim of this study was to determine electromyographically the relationship between the TOFRs of the FHBM and the first dorsal interosseous muscle (FDIM), following 0.1 mg/kg of vecuronium. Eighteen patients were enrolled in this study. Electromyography of the FDIM and the FHBM was monitored. Onset times and recovery times to TOFRs of 0.7 and 0.9 of both muscles after administration of vecuronium were measured. The onset time in the FDIM was not different from that in the FHBM (𝑃 = 0.10). Recovery time to TOFR 0.7 was significantly faster in the FHBM than in the FDIM (𝑃 < 0.013). There was no significant difference in the meantime to reach TOFR 0.9 between the FDIM and the FHBM (𝑃 = 0.11). There is no clinical importance in the difference of neuromuscular recovery between the FHBM and the FDIM after TOFR reached 0.9 following administration of vecuronium. Yasuyuki Sugi, Keiichi Nitahara, Kazuo Higa, Go Kusumoto, and Shinjiro Shono Copyright © 2011 Yasuyuki Sugi et al. All rights reserved. Dementia Enhances Inhibitory Actions of General Anesthetics in Hippocampal Synaptic Transmission Wed, 21 Dec 2011 13:15:35 +0000 In order to investigate whether dementia modifies the anesthetic actions in the central nervous systems, we have studied effects of general anesthetics on the hippocampal synaptic transmission using the dementia model mice. Preliminary in vivo experiments revealed that time of loss of righting reflex following sevoflurane inhalation was more shortened in dementia mice than in healthy control mice. Field population spikes of hippocampal CA1 pyramidal neurons were elicited in vitro using orthodromic stimulation of Schaffer collateral commissural fibers (test pulse). The recurrent inhibition was enhanced with the second stimulating electrode placed in alveus hippocampi (prepulse) to activate recurrent inhibition of CA1. The prepulses were applied as train stimuli to activate release and then deplete γ-amino-butyric acid (GABA) at presynaptic terminals of inhibitory interneurons. Sevoflurane and thiopental had greater actions on inhibitory synaptic transmission in dementia model mice than in control mice. The pre-pulse train protocol revealed that the anesthetic-induced GABA discharge was more enhanced in dementia mice than in control mice. Dementia enhances the actions of general anesthetics due to the increase in GABA release from presynaptic terminals. Masana Yamada, Rika Sasaki, Koki Hirota, and Mitsuaki Yamazaki Copyright © 2011 Masana Yamada et al. All rights reserved. Local Anaesthetic Infiltration in Joint Replacement Surgery: What Is Its Role in Enhanced Recovery? Thu, 15 Dec 2011 17:14:04 +0000 The last 10 years has seen the increased use of enhanced recovery pathways across several surgical specialities. A prerequisite of enhanced recovery is the ability to mobilise patients early. This is dependent upon good postoperative pain control. A number of different techniques have been employed in joint replacement surgery to address this issue. This paper focuses upon the current evidence for local infiltration anaesthesia. Ian Starks, Tom Wainwright, and Robert Middleton Copyright © 2011 Ian Starks et al. All rights reserved. The Central Role of Glia in Pathological Pain and the Potential of Targeting the Cannabinoid 2 Receptor for Pain Relief Sun, 11 Dec 2011 07:52:15 +0000 Under normal conditions, acute pain processing consists of well-characterized neuronal signaling events. When dysfunctional pain signaling occurs, pathological pain ensues. Glial activation and their released factors participate in the mediation of pathological pain. The use of cannabinoid compounds for pain relief is currently an area of great interest for both basic scientists and physicians. These compounds, bind mainly either the cannabinoid receptor subtype 1 (CB1R) or cannabinoid receptor subtype 2 (CB2R) and are able to modulate pain. Although cannabinoids were initially only thought to modulate pain via neuronal mechanisms within the central nervous system, strong evidence now supports that CB2R cannabinoid compounds are capable of modulating glia, (e.g. astrocytes and microglia) for pain relief. However, the mechanisms underlying cannabinoid receptor-mediated pain relief remain largely unknown. An emerging body of evidence supports that CB2R agonist compounds may prove to be powerful novel therapeutic candidates for the treatment of chronic pain. Jenny L. Wilkerson and Erin D. Milligan Copyright © 2011 Jenny L. Wilkerson and Erin D. Milligan. All rights reserved. Retrospective Validation of New Simulation Software to Prevent Perioperative Hypothermia in Major Urologic Abdominal Surgery Thu, 08 Dec 2011 09:25:27 +0000 Background. Perioperative hypothermia is still a major problem. Therefore, it would be useful to predict which warming method would prevent perioperative hypothermia in a particular patient. Methods. The simulation software “ThermoSim Vers. 5.07” was validated using the data of two prospective, randomized, and controlled studies. The diagnostic effectiveness was assessed by calculating sensitivity and specificity, positive predictive value (PPV), and negative predictive value (NPV) in the detection of perioperative hypothermia. Results. Sensitivity of the software was 100% (Study 1) and 94% (Study 2), specificity was 67% (Study 1) and 38% (Study 2), PPV was 60% (Study 1) and 50% (Study 2), and NPV was 100% (Study 1) and 90% (Study 2). Conclusions. The software is helpful in predicting which warming method is necessary to prevent perioperative hypothermia. Thermal treatment based on the prediction of the software will lead to some overtreatment, but will prevent perioperative hypothermia reliably. Anselm BrΓ€uer, Sebastian Gassner, Jochim Koch, Daniel Heise, and Michael Quintel Copyright © 2011 Anselm Bräuer et al. All rights reserved. The Loss of Resistance Nerve Blocks Wed, 07 Dec 2011 15:00:07 +0000 Presently ultrasound guided nerve blocks are very fashionable but vast majority of people around the world cannot practice these techniques mostly due to lack of resources but even in the developed countries there is lack of training which precludes people from using it. Lack of resources does not mean that patient cannot be provided with appropriate pain relief using nerve blocks. There are some nerve blocks that can be done using the loss of resistance (LOR) techniques. These blocks like, tranversus abdominis plane (TAP), rectus sheath, ilio-inguinal and fascia iliaca blocks can be effectively utilized to provide pain relief in the peri-operative period. For these blocks to be effectively delivered it is essential to understand the anatomical basis. It is also important to understand the reasons for failure, which is mostly due to delivery of the local anaesthetic in the wrong plane. The technique for LOR is not only simple and effective but also it can be delivered with minimal resources. This article deals with the techniques used for LOR blocks, the relevant anatomy and the methods used to administer the blocks. The article also describes the various indications where these blocks can be utilized, especially in the post-operative period where the pain management is sub-optimal. Shiv Kumar Singh and S. M. Gulyam Kuruba Copyright © 2011 Shiv Kumar Singh and S. M. Gulyam Kuruba. All rights reserved. Sevoflurane Induction Shortens the Onset of Vecuronium at the Corrugator Supercilii Muscles: A Randomized Comparison with Propofol Induction Mon, 28 Nov 2011 15:25:57 +0000 We evaluated if induction with sevoflurane shortened the onset of vecuronium-induced neuromuscular blockade at the corrugator supercilii muscles (which have a similar time course of neuromuscular blockade with laryngeal muscles). Thirty-two patients were randomly allocated to a sevoflurane or propofol group. Anesthesia was induced with 5% sevoflurane in oxygen (sevoflurane group, 𝑛=16) or with propofol 2–2.5 mg kg−1(propofol group, 𝑛=16), and vecuronium (0.1 mg kg−1) was given in both groups. Evoked responses to train-of-four stimuli were measured by acceleromyography at the corrugator supercilii and adductor pollicis muscles. Sevoflurane induction, as compared with propofol, significantly shortened the onset time at the corrugator supercilii muscles from 138 ± 34 s to 107 ± 28 s (𝑃<0.01). Onset time at the corrugator supercilii was significantly shorter than at the adductor pollicis for both groups (𝑃<0.01). Our results suggest that induction with sevoflurane, as compared with propofol, shortened the onset time of vecuronium at laryngeal muscles. Keiichi Nitahara, Yasuyuki Sugi, Go Kusumoto, Kiyoshi Katori, Kohei Iwashita, and Kazuo Higa Copyright © 2011 Keiichi Nitahara et al. All rights reserved. The Cost Implications of Replacing Soda Lime with Amsorb Plus in Clinical Practice Thu, 24 Nov 2011 13:24:35 +0000 Background and Goal of the Study. Desiccated soda lime is known to produce toxic compounds when interacting with volatile anesthetic agents. Amsorb Plus does not produce these but is more expensive per unit weight. Materials and Methods. In a prospective cross-over study, we evaluated the cost of using soda lime (Spherasorb, Intersurgical, UK) and Amsorb Plus. In four operating theatres over two 4-week periods, one for each product, we measured sevoflurane consumption, amount of absorbent used (kg), and amount of waste disposal (kg). Soda lime was changed weekly, and Amsorb Plus once colour change happened. Both were changed if inspired CO2 occurred. Low fresh gas flows were encouraged with Amsorb Plus. Results and Discussion. The total costs over each four-week period were €4375.69 and €3150.94 for soda lime and Amsorb Plus respectively. Reduced cost during Amsorb Plus period (28%) was due to (1) less sevoflurane consumption, (2) fewer Amsorb Plus changes because of reliable colour change, and (3) cheaper domestic waste disposal of Amsorb Plus as it is inert. Conclusion. We demonstrated Amsorb Plus to be a cost-efficient alternative to soda lime in everyday clinical practice. Osman Ahmed and Stephen Mannion Copyright © 2011 Osman Ahmed and Stephen Mannion. All rights reserved. No Perioperative Pulmonary Complications after Restricted Oxygen Exposition in Bleomycin-Treated Patients: A Short Report Thu, 24 Nov 2011 10:04:40 +0000 Hyperoxic exposure during general anaesthesia after receiving bleomycin treatment is purported to potentiate bleomycin-induced pulmonary toxicity. The aim of this study was to retrospectively assess perioperative pulmonary complications after general anaesthesia for retroperitoneal lymphadenectomy in patients who underwent bleomycin treatment <6 months earlier. A consecutive series of 47 patients who underwent surgery after bleomycin treatment were reviewed. Anaesthesia was induced with an inspired fraction of oxygen (FiO2) of 100% for 3 minutes and pertained with a FiO2 just under 30% throughout the procedure. We assessed all potential risk factors for bleomycin-induced pulmonary toxicity. Clinical signs for pulmonary damage were documented preoperatively (dyspnea, tachypnea, nonproductive cough, and postoperative oxygen saturation problems). No pathognomic clinical signs for pulmonary damage were detected up to 7 days postoperatively. Administration of 100% oxygen for 3 minutes during induction of anaesthesia and maintaining a FiO2 < 30% during surgery was safe. Patrick Y. Wuethrich and Fiona C. Burkhard Copyright © 2011 Patrick Y. Wuethrich and Fiona C. Burkhard. All rights reserved.