Effect of intravenous magnesium on post-operative pain following Latarjet shoulder reconstruction.

Background: Single injection ropivacaine interscalene anesthesia (ISA) is frequently used in Latarjet reconstruction to enhance post-operative analgesia. A potential limitation is the occurrence of severe rebound pain on block resolution. We investigated the effect of intravenous magnesium on post-operative pain, particularly at the transition of block resolution to multimodal analgesia.

Antibody or Anybody? Considering the Role of MRGPRX2 in Acute Drug-Induced Anaphylaxis and as a Therapeutic Target.

Acute anaphylaxis to small molecule drugs is largely considered to be antibody-mediated with immunogloblin E (IgE) and mast cell activation being key. More recently, a role for drug-reactive immunoglobulin G (IgG) with neutrophil activation has also been suggested, at least in reactions to neuromuscular blocking agents (NMBAs). However, the mast cell receptor MRGPRX2 has also been highlighted as a possible triggering mechanism in acute anaphylaxis to many clinically used drugs.

MRGPRX2 activation in mast cells by neuromuscular blocking agents and other agonists: Modulation by sugammadex.

Background: Neuromuscular-blocking agents (NMBAs) can cause both IgE-dependent and IgE-independent anaphylactic reactions, with activation of the mast cell receptor MRGPRX2 being important to the latter. Sugammadex, a reversal agent for certain aminosteroid NMBAs, has been proposed as an antidote for these anaphylactic events with conflicting outcomes.

Objective: We further characterize the involvement of MRGPRX2 in NMBA-induced mast cell activation and determine how this is influenced by sugammadex.

Sustained cardiac programming by short-term juvenile exercise training in male rats.

Key Points: Cardiac hypertrophy following endurance-training is thought to be due to hypertrophy of existing cardiomyocytes. The benefits of endurance exercise on cardiac hypertrophy are generally thought to be short-lived and regress to sedentary levels within a few weeks of stopping endurance training. We have now established that cardiomyocyte hyperplasia also plays a considerable role in cardiac growth in response to just 4 weeks of endurance exercise in juvenile (5-9 weeks of age) rats.

Evaluation of right heart function in a rat model using modified echocardiographic views.

Echocardiography plays a major role in assessing cardiac function in animal models. We investigated use of a modified parasternal mid right-ventricular (MRV) and right ventricle (RV) outflow (RVOT) view, in assessing RV size and function, and the suitability of advanced 2D-strain analysis. 15 WKY rats were examined using transthoracic echocardiography.

Functional estimation of endothelin-1 receptor antagonism by bosentan, macitentan and ambrisentan in human pulmonary and radial arteries in vitro.

Background: Endothelin receptor antagonists are approved for pulmonary arterial hypertension. Development of selective ET-receptor antagonists over mixed or dual receptor antagonists has depended on a range of receptor binding assays, second messenger assays and functional blood vessel assays. This study compared the 3 clinically-approved endothelin receptor antagonists in assays of human isolated pulmonary and radial arteries in vitro.

Sensory Distribution of the Lateral Cutaneous Nerve of Forearm After Ultrasound-Guided Block: Potential Implications for Thumb-Base Surgery.

Surgery of the wrist and hand commonly involves regional anesthesia of the median nerve and superficial radial nerve within the forearm. In this sonographic study, the contribution of the lateral cutaneous nerve of forearm (LCNF) to thumb cutaneous sensation was studied. Patients scheduled for thumb suspension arthroplasty (n = 35) were examined by ultrasound, with LCNF, median nerve, and superficial radial nerve identified.

Effect of interscalene anaesthesia on cerebral oxygen saturation.

Interscalene blockade (ISB) is commonly associated with Horner's syndrome, indicating spread of injectate to the cervical sympathetic chain. Cervical sympathetic nerve activity (SNA) is believed to influence cerebral autoregulation, and a decrease in sympathetic tone may alter cerebral blood flow (CBF). This study investigated whether ISB influenced CBF in patients undergoing shoulder surgery.

The role of voltage-operated and non-voltage-operated calcium channels in endothelin-induced vasoconstriction of rat cerebral arteries.

Endothelin-1 has been identified as a potential mediator in the pathogenesis of ischaemic stroke and cerebral vasospasm. The aim of this study was to analyse the role of voltage-operated calcium channels (VOCC) and non-VOCC in endothelin-1 induced vasoconstriction of rat cerebral arteries. Arterial segments were dissected from different regions of the cerebral circulation and responses assessed using wire myography.

Vasoconstrictor responses to vasopressor agents in human pulmonary and radial arteries: an in vitro study.

Background: Vasopressor drugs, commonly used to treat systemic hypotension and maintain organ perfusion, may also induce regional vasoconstriction in specialized vascular beds such as the lung. An increase in pulmonary vascular tone may adversely affect patients with pulmonary hypertension or right heart failure. While sympathomimetics constrict pulmonary vessels, and vasopressin does not, a direct comparison between these drugs has not been made.

Effect of phenylephrine on the haemodynamic state and cerebral oxygen saturation during anaesthesia in the upright position.

Background: The upright sitting or beachchair position is associated with hypotension, risk of cerebral hypoperfusion, and cerebral injury. We hypothesized that by increasing arterial pressure with phenylephrine administration, cerebral perfusion, and postoperative recovery would be improved.

Methods: Thirty-four patients undergoing elective shoulder surgery were randomized to receive either saline or phenylephrine infusion (PE) 5 min before being placed in the upright position.

The effect of the sitting upright or 'beachchair' position on cerebral blood flow during anaesthesia for shoulder surgery.

The sitting upright or 'beachchair' position is commonly used for shoulder arthroscopic surgery. There is a theoretical concern that anaesthetised patients placed in this posture are at risk of reduced cerebral blood flow (CBF), especially if there is associated hypotension. This study investigated the effect of anaesthetic-induced hypotension on estimated cerebral blood flow in patients placed in the beachchair position for shoulder surgery.

Levosimendan preserves the contractile responsiveness of hypoxic human myocardium via mitochondrial K(ATP) channel and potential pERK 1/2 activation.

This study investigated the role of levosimendan, a mitochondrial K(ATP) channel opener, during hypoxia-reoxygenation injury in human isolated tissue. The activation of preconditioning pathways, and the release of mitochondrial cytochrome c were determined. Human right atrial trabeculae were mounted in an organ bath, electrically paced and contractile force measured.

Pulse-oximetric measurement of prilocaine-induced methemoglobinemia in regional anesthesia.

Background: The Masimo Radical 7(®) is a new pulse CO oximeter designed to measure methemoglobin. The device has not been evaluated in a clinical setting.

Methods: In this prospective observational study we compared the arterial methemoglobin levels and the corresponding pulse CO-oximetric values of the Radical 7(®) in regional anesthesia with prilocaine.

Review article: anatomical considerations for ultrasound guidance for regional anesthesia of the neck and upper limb.

Purpose: The purpose of this narrative review is to describe an anatomical approach for residents-in-training and anesthesiologists who are learning techniques of ultrasound-guided regional anesthesia of the neck and upper limb.

Sources: Relevant articles relating anatomy and anatomical variation to the emerging practice of ultrasound-guided regional anesthesia for the neck and upper limb were sourced via both Medline and PubMed databases. Also, our approach to teaching ultrasound technique has developed from using anatomical resources and cadaveric workshops.

Cold agglutinins in cardiac surgery: management of myocardial protection and cardiopulmonary bypass.

Cold agglutinins are of unique relevance in cardiac surgery because of the use of hypothermic cardiopulmonary bypass (CPB). Immunoglobulin M autoantibodies to red blood cells, which activate at varying levels of hypothermia, can cause catastrophic hemagglutination, microvascular thrombosis, or hemolysis. Management of CPB and myocardial protection requires individualized planning.

Inoprotection: the perioperative role of levosimendan.

Levosimendan is emerging as a novel cardioprotective inotrope. Levosimendan augments myocardial contractility by sensitising contractile myofilaments to calcium without increasing myosin adenosine triphosphatase activity or oxygen consumption. Levosimendan activates cellular adenosine triphosphate-dependent potassium channels, a mechanism which is postulated to protect cells from ischaemia in a manner similar to ischaemic preconditioning.

High thoracic epidural analgesia for cardiac surgery: an audit of 874 cases.

Despite clinical use for over 10 years, high thoracic epidural analgesia for cardiac surgery remains controversial, due to a perceived increased risk of epidural haematoma resulting from anticoagulation for cardiac pulmonary bypass. There are no sufficiently large randomised studies to address this question and few large case series reported. For this reason, we conducted an audit of neurological complications related to high thoracic epidural analgesia during cardiac surgery in our institution between 1998 and end 2005.

Anatomical study of the brachial plexus using surface ultrasound.

The aim of this study was to define the anatomy relevant to brachial plexus regional anaesthesia and to identify the extent of variation between individuals. Surface ultrasound examination of the brachial plexus was performed on twenty volunteers. In the axilla there was considerable individual variation in the location of the median, radial and ulnar nerves in relation to the axillary artery.

A randomized trial of ultrasound-guided brachial plexus anaesthesia in upper limb surgery.

Ultrasound guidance allows real-time identification of relevant anatomy and needle position when performing brachial plexus regional anaesthesia. The aim of this investigation was to determine whether the use of surface ultrasound could improve the quality of brachial plexus anaesthesia for upper limb surgery. Forty patients were randomized to either conventional "landmark-based" plexus anaesthesia, or to an ultrasound-guided approach using a 13 mHz linear array transducer Both interscalene and axillary techniques were used.