Inflammatory Response in Patients under Coronary Artery Bypass Grafting Surgery and Clinical Implications: A Review of the Relevance of Dexmedetomidine Use

Despite the fact that coronary artery bypass grafting surgery (CABG) with cardiopulmonary bypass (CPB) prolongs life and reduces symptoms in patients with severe coronary artery diseases, these benefits are accompanied by increased risks. Morbidity associated with cardiopulmonary bypass can be attributed to the generalized inflammatory response induced by blood-xenosurfaces interactions during extracorporeal circulation and the ischemia/reperfusion implications, including exacerbated inflammatory response resembling the systemic inflammatory response syndrome (SIRS). The use of specific anesthetic agents with anti-inflammatory activity can modulate the deleterious inflammatory response. Consequently, anti-inflammatory anesthetics may accelerate postoperative recovery and better outcomes than classical anesthetics. It is known that the stress response to surgery can be attenuated by sympatholytic effects caused by activation of central (α-)2-adrenergic receptor, leading to reductions in blood pressure and heart rate, and more recently, that they can have anti-inflammatory properties. This paper discusses the clinical significance of the dexmedetomidine use, a selective (α-)2-adrenergic agonist, as a coadjuvant in general anesthesia. Actually, dexmedetomidine use is not in anesthetic routine, but this drug can be considered a particularly promising agent in perioperative multiple organ protection.

Propofol Protects against Ischemia/Reperfusion Injury Associated with Reduced Apoptosis in Rat Liver

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.

Anesthetic Management in Mucopolysaccharidoses

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.

Effect of Two Different Doses of Gabapentin on the Intraocular Pressure and Hemodynamic Stress Responses to Laryngoscopy and Tracheal Intubation

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.

Midazolam in Subarachnoid Block: Current Evidence

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.

Pharmacoeconomics and Pharmacodynamic Interactions of Rocuronium and Pancuronium

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 36.84 ± 2.54, 74.60 ± 4.94, and 40.81 ± 2.34, respectively. The mean cost of intubation per patient was 316.71 ± 83.61 INR in group R, 52.30 ± 14.94 INR in group P, and 93.33 ± 20.65 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.

Comparative Effects of Single Shot Intrathecal Bupivacaine with Dexmedetomidine and Bupivacaine with Fentanyl on Labor Outcome

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.

Utilization of a Swine (Sus scrofa) Model for Lipid Emulsion Resuscitation Studies

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.

Evaluation of Airway Scope at Improving the Success Rate of the First Intubation Attempt by Nonexpert Physicians: A Randomized Crossover Manikin Study

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 (P=0.32). The outcomes achieved by the AWS in scenarios involving cervical immobilization (P=0.03), tongue edema (P≤0.001), pharyngeal obstruction (P≤0.001), and jaw trismus (P=0.001) 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.

MicroPET/CT Imaging of [18F]-FEPPA in the Nonhuman Primate: A Potential Biomarker of Pathogenic Processes Associated with Anesthetic-Induced Neurotoxicity

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.