Michael Stuart Green

Randomized, double-blind comparison of oral aprepitant alone compared with aprepitant and transdermal scopolamine for prevention of postoperative nausea and vomiting

BACKGROUND Aprepitant blocks the emetic effects of substance P. Scopolamine antagonizes muscarinic type 1 and histamine type 1 receptors. This study compares monotherapy and multimodal therapy by looking at complete response, nausea, vomiting, and rescue medication in patients at high risk for postoperative nausea and vomiting (PONV) treated with oral aprepitant with or without scopolamine. METHODS We enrolled 120 patients in this randomized, double-blind trial. Inclusion criteria were: >18 yr old, ASA I-III, two or more Apfel four-point risk factors, undergoing an elective surgical procedure with a high risk of PONV expected to last at least 60 min. The primary outcome variable was complete response, that is, no emesis and no rescue therapy from 0 to 24 h. The outcomes measured included the incidences of nausea, vomiting, their composite, and the need for rescue medication. RESULTS The aprepitant alone and aprepitant with scopolamine did not differ in complete responses (63% vs 57%, P=0.57) or net clinical benefit (26% vs 19%, P=0.38). The number who did not experience PONV and who used rescue medication did not differ. The incidence of PONV in the post-anaesthesia care unit did not differ nor did the use of rescue medications. CONCLUSIONS This trial evaluating the effectiveness of aprepitant alone and in combination with scopolamine showed no difference between treatment groups. The primary objective, complete response, and secondary objectives, incidences of nausea, vomiting, their composite, and the need for rescue medication, all showed no statistical difference.

Near-Infrared Spectroscopy The New Must Have Tool in the Intensive Care Unit?

Standard hemodynamic monitoring such as blood pressure and pulse oximetry may only provide a crude estimation of organ perfusion in the critical care setting. Near-infrared spectroscopy (NIRS) is based on the same principle as a pulse oximeter and allows continuous noninvasive monitoring of hemoglobin oxygenation and deoxygenation and thus tissue saturation “StO2.” This review aims to provide an overview of NIRS technology principles and discuss its current clinical use in the critical care setting. The study selection was performed using the PubMed database to find studies that investigated the use of NIRS in both the critical care setting and in the intensive care unit. Currently, NIRS in the critical care setting is predominantly being used for infants and neonates. A number of studies in the past decade have shown promising results for the use of NIRS in surgical/trauma intensive care units during shock management as a prognostic tool and in guiding resuscitation. It is evident that over the past 2 decades, NIRS has gone from being a laboratory fascination to an actively employed clinical tool. Even though the benefit of routine use of this technology to achieve better outcomes is still questionable, the fact that NIRS is a low-cost, noninvasive monitoring modality improves the attractiveness of the technology. However, more research may be warranted before recommending its routine use in the critical care setting.

Improving Patient Safety through Simulation Training in Anesthesiology: Where Are We?

There have been colossal technological advances in the use of simulation in anesthesiology in the past 2 decades. Over the years, the use of simulation has gone from low fidelity to high fidelity models that mimic human responses in a startlingly realistic manner, extremely life-like mannequin that breathes, generates E.K.G, and has pulses, heart sounds, and an airway that can be programmed for different degrees of obstruction. Simulation in anesthesiology is no longer a research fascination but an integral part of resident education and one of ACGME requirements for resident graduation. Simulation training has been objectively shown to increase the skill-set of anesthesiologists. Anesthesiology is leading the movement in patient safety. It is rational to assume a relationship between simulation training and patient safety. Nevertheless there has not been a demonstrable improvement in patient outcomes with simulation training. Larger prospective studies that evaluate the improvement in patient outcomes are needed to justify the integration of simulation training in resident education but ample number of studies in the past 5 years do show a definite benefit of using simulation in anesthesiology training. This paper gives a brief overview of the history and evolution of use of simulation in anesthesiology and highlights some of the more recent studies that have advanced simulation-based training.

Vasoplegic syndrome: An update on perioperative considerations.

Vasoplegic syndrome (VS) is increasingly recognized as an important clinical entity in perioperative medicine. VS is characterized by significant arterial hypotension, normal or high cardiac output, low systemic vascular resistance, and increased requirements for intravenous volume and vasopressors. Tremendous variations exist regarding incidence reported in the literature and management at different institutions; and the incidence of VS is likely significantly higher than many anesthesiologists believe. Thus the aims of this article are to review the pertinent aspects related to VS and alert clinical anesthesiologists to this under-recognized yet very challenging clinical condition. The potential risk factors include blood transfusion, cardiopulmonary bypass, organ transplantation, trauma and sepsis, and use of specific medications such as angiotensin-converting enzyme inhibitors, Angiotensin-II antagonist, heparin, amiodarone, aprotinin, and protamine. The pathogenesis of VS may have several mechanistic pathways, overproduction of inducible nitric oxide, activation of ATP-dependent K channels, vasopressin V1A-receptor down-regulation, and nuclear factor-κB activation. Current management strategies include intravenous administration of volume and catecholamines, vasopressin, methylene blue and high dose hydroxocobalamin. Other treatment could include ATP-sensitive K channel blocker, nuclear factor-κB inhibitor, indigo carmine, and hyperbaric oxygen therapy. VS is still associated with significantly increased perioperative morbidity and mortality.

Carbon monoxide-releasing molecule-2 enhances coagulation and diminishes fibrinolytic vulnerability in diluted plasma in vitro.

BACKGROUND A carbon monoxide-releasing molecule (tricarbonyldichlororuthenium (II) dimer; CORM-2) enhances coagulation and attenuates vulnerability to fibrinolysis in normal and hemophiliac human plasma. We tested the hypothesis that plasma diluted with resuscitative fluids would demonstrate improved coagulation and decreased fibrinolytic vulnerability after exposure to CORM-2. METHODS Normal, platelet-poor plasma was diluted 0%, 20%, 30%, 40%, or 50% with 0.9% NaCl (NS) or low-molecular-weight hydroxyethyl starch (VOL) and, subsequently, exposed to 0 μmol/L or 100 μmol/L CORM-2 before activation with tissue factor (n = 4 per condition). Additional plasma samples diluted with NS or VOL (0% or 30%) were exposed to 0 μmol/L or 100 μmol/L CORM-2 and 0 U/mL or 100 U/mL tissue-type plasminogen activator to assess fibrinolytic vulnerability (n = 8 per condition). Thrombelastographic data were collected until either clot strength stabilized or clot lysis occurred, as appropriate. RESULTS CORM-2 exposure maintained normal to supranormal velocity of clot formation and strength in plasma diluted up to 40% with NS. In contrast, although CORM-2 exposure improved coagulation kinetics, dilution with VOL markedly degraded thrombus formation kinetics. Similarly, fibrinolytic vulnerability to tissue-type plasminogen activator was markedly improved by CORM-2 exposure in samples diluted with NS, whereas VOL-diluted thrombi were still abnormally weak and easily lysed compared with undiluted samples despite CORM-2 exposure. CONCLUSIONS CORM-2 exposure attenuated the decrease in coagulation kinetics and enhancement of fibrinolytic vulnerability associated with hemodilution. Extensive preclinical investigation remains to be performed to determine the route of administration, safety, and efficacy of CORM-2 and other CORMs to treat trauma-associated bleeding.

Near-infrared spectroscopy for the evaluation of anesthetic depth.

The standard-of-care guidelines published by the American Society of Anesthesiologists (ASA) recommend monitoring of pulse oximetry, blood pressure, heart rate, and end tidal CO2 during the use of anesthesia and sedation. This information can help to identify adverse events that may occur during procedures. However, these parameters are not specific to the effects of anesthetics or sedatives, and therefore they offer little, to no, real time information regarding the effects of those agents and do not give the clinician the lead-time necessary to prevent patient “awareness.” Since no “gold-standard” method is available to continuously, reliably, and effectively monitor the effects of sedatives and anesthetics, such a method is greatly needed. Investigation of the use of functional near-infrared spectroscopy (fNIRS) as a method for anesthesia or sedation monitoring and for the assessment of the effects of various anesthetic drugs on cerebral oxygenation has started to be conducted. The objective of this paper is to provide a thorough review of the currently available published scientific studies regarding the use of fNIRS in the fields of anesthesia and sedation monitoring, comment on their findings, and discuss the future work required for the translation of this technology to the clinical setting.

Recovery Following Desflurane Versus Sevoflurane Anesthesia for Outpatient Urologic Surgery in Elderly Females

Background: An unresolved question is the time required for the ability to return to complex tasks following anesthesia. Objectives: This study aims to characterize the severity and duration of cognitive impairment following sevoflurane or desfluane anesthesia after brief surgery using tests of cognitive ability to objectively testing performance. Patients and Methods: This study is a double blinded randomized controlled trial. Patients were randomized to receive either a desflurane or sevoflurane-based anesthetic. On the morning of the surgery the subjects performed baseline cognitive task tests (Mini Mental Status exam, Trail Making Test Part A and B, Digit Symbol Coding, Hopkins Verbal Learning Test, Stroop Color and Word Test to determine baseline cognitive function. Cognitive testing was repeated 30 minutes and 1 hour after surgery whereas Modified Telephone Interview for Cognitive Status (TICS-M) and Memory Aging Telephone Screen (MATS) was used on the following day of surgery. Results: Trail Making Test Part B cognitive test showed statistically significant in comparison for pre and post exposure of anesthetics. This difference was seen in the desflurane group. Other cognitive tests did not show differences on exposure to the anesthetic gases. Conclusions: This study questioned the difference between volatile anesthetic agent’s effects on patients completing a battery of neurocognitive tests attempting to answer if one agent has a more profound effect. Our study shows no statistically significant cognitive decline except for those in the Trail Making Part B in the Desflurane group. This conclusion is limited by the inherent limitations of the study, but does reinforce that the systemic inflammatory response from the surgery contributes cognitive impairment.

Subdural hematoma following labor analgesia utilizing an intrathecal catheter.

To the Editor: We report a subdural hematoma following repeated neuraxial analgesia during labor. A healthy parturient presented with an unremarkable preanesthetic examination. At L3–L4, an 18-gauge Tuohy was advanced until a depth of 4 cm. Free-flowing cerebral spinal fluid (CSF) confirmed accidental dural puncture. A 20-gauge catheter was advanced 4 cm into the intrathecal space (IT) and secured at 8 cm at the skin. One milliliter bupivacaine 0.25 % with sufentanil 5 lg preceded infusion of bupivacaine 0.0625 % with fentanyl 1.5 lg/ml and epinephrine 1:700,000 at 2 ml/ h. Four hours later, analgesia became less potent. On inspection the catheter unintentionally came out to 4 cm, thus exiting the IT. Aspiration no longer produced freeflowing CSF. Vaginal exam revealed advancement of labor. Repeat epidural catheterization at L2–L3 followed. Ten milliliters bupivacaine 0.25 % and the same infusion solution yielded analgesia. On postpartum day (PPD) 1, bilateral headache without photophobia appeared. By PPD 3 pain was nonradiating, worsened with standing, and not improved with fluid or caffeine. Examination yielded no focal neurological deficits. Magnetic resonance imaging on PPD 3 demonstrated hyperintensity along the left frontoparietal convexity and left tentorium consistent with subdural hematoma (Fig. 1). Medical management included oxycodone/acetaminophen, tramadol, ibuprofen, and morphine until PPD 9. Computed tomography on PPD 7 revealed stability. Dural puncture is a common complication of epidural placement, with incidence of 0.3 % [1]. Pressure decrease results in traction on the meninges and vascular structures, yielding headache [2]. Infrequently, subdural hematoma occurs following low CSF pressure, causing vein dilatation and traction on bridging veins, resulting in tearing [2]. Prompt epidural blood patching may influence subdural hematoma formation by sealing the dural leak. Recently, advancing a catheter into the IT following dural puncture has been advocated [3]. Kuczkowski and Benumof recommended five steps: (1) injection of CSF into the IT through the needle; (2) insertion of an IT catheter; (3) continuous intrathecal labor analgesia; (4) leaving the catheter in situ for 12–20 h; and (5) injection of 3–5 ml preservative-free saline into the IT before removal [4]. Intrathecal catheter placement does not negate all risk. The anesthesiologist must frequently check for accidental catheter removal. Unrecognized displacement increases the risk of subdural hematoma [5]. Following intrathecal catheter analgesia, patients need frequent monitoring for early recognition of complications. Anticoagulation, cerebral atrophy, dehydration, arteriovenous malformations, and excessive CSF leakage [5] are M. S. Green S. George P. Green Department of Anesthesia, Hahnemann University Hospital, Drexel University College of Medicine, Philadelphia, PA, USA

Management of Residual Neuromuscular Blockade Recovery: Age-Old Problem with a New Solution

Neostigmine has been traditionally used as the agent of choice to reverse Neuromuscular Blockade (NMB) after muscle paralysis during general anesthesia. However, the use of neostigmine has not been without untoward events. Sugammadex is a novel drug that selectively binds to aminosteroid nondepolarizing muscle relaxants and reverses even a deep level of NMB. Controversy exists regarding the optimal dose of sugammadex that is effective in reversing the NMB after the incomplete reversal with neostigmine and glycopyrrolate. We discuss a case where sugammadex reduced the time of the recovery from NMB in a patient who had incomplete antagonisms following adequate treatment with neostigmine, aiding timely extubation without persistent residual NMB, and hence prevented the requirement of postoperative ventilation and the improvement in patient care. More randomized control studies are needed in order to conclude the appropriate dose of sugammadex in cases of incomplete reversal.

Anomalous Coronary Artery Run of a Lifetime

The anatomy of the coronary circulation is well described with incidence of congenital anomalies of approximately 0.3% to 1.0%. Although often incidental, 20% are life-threatening. A 25-year-old woman with syncopal episodes collapsed following a 10-km run. Coronary anatomy evaluation showed an anomalous left main coronary artery originating from the right sinus of valsalva and following a course between the aorta and the pulmonary outflow tract. Percutaneous coronary intervention was followed by eventual surgical revascularization. Abnormal course of coronary arteries plays a role in the pathogenesis of sudden death on exertion. Origin of the left main coronary from the right sinus of valsalva is a rare congenital anomaly. The expansion of the roots of the aorta and pulmonary trunk with exertion lead to compression of the coronary artery and syncope. Our patient raises awareness of a potentially fatal coronary artery path. Intraoperative identification of anomalous coronaries by utilizing intraoperative transesophageal echocardiography was critical.