Anaesthesia reports最新文献

A 71-year-old man was admitted to the Cardiothoracic Intensive Care Unit following implantation of a left ventricular assist device (LVAD) (Impella, Abiomed, Danvers, MA, USA) and percutaneous coronary intervention (PCI) procedure. His medical history included coronary artery disease and end-stage chronic kidney disease requiring haemodialysis via an arteriovenous (AV) fistula on his right arm. He was transferred to our centre with new onset heart failure and was found to have a left ventricular ejection fraction of 22% on transthoracic echo. Percutaneous coronary intervention was deemed too high risk to undertake without LVAD support. During a protracted recovery, on day 46, he required a replacement central venous catheter (CVC) and dialysis catheter. The left internal jugular vein was chosen due to the presence of existing vascular access devices elsewhere. An 8.5 Fr, 20 cm quad-lumen CVC (Multicath 4expert, Vygon, Aachen, Germany) and a 13.5 Fr, 20 cm dual lumen dialysis catheter (Hemo-cath, Nikkiso Co Ltd, Tokyo, Japan) were sited at a depth of 18 cm and 17 cm respectively, with the dialysis catheter placed proximally.

Blood gas analysis from the distal lumen of the new CVC showed a pO₂ of 10.8 kPa (F_IO₂ of 0.28). A contemporaneous arterial line sample indicated an arterial pO₂ of 10.5 kPa. A sample from the distal lumen of the dialysis catheter indicated a more reassuring pO₂ of 4.24 kPa. Repeat CVC samples showed a pO₂ of 10 kPa from the distal lumen whilst samples taken from proximal CVC lumens indicated a pO₂ of 4.62 kPa, consistent with venous results. Because of these results, we were concerned that the CVC had punctured the left carotid artery. Neither line was transduced at this stage and a computed tomography (CT) angiogram was arranged urgently, which confirmed an appropriate position for both lines (Fig. 1).

This case highlights the difficulty of interpreting blood gas samples taken from a CVC in a patient with an AV fistula. The presence of a high pO₂ cannot be interpreted accurately because of abnormal flow of arterial blood from the fistula. However, results compatible with venous samples were taken from the proximal lumens of the CVC which complicated the interpretation of results. Although rare, cases of patients with AV fistulae in whom CVC location is unclear due to unexpected blood gas analysis data have been previously reported [1, 2]. It is well established that the central veins demonstrate laminar flow and that laminae vary in their oxygenation, indicating that mixing of content between the laminae does not necessarily occur [3]. It seems most likely in our case that the distal CVC lumen was situated sufficiently close to the fistula to allow aspiration from an arterial, well-oxygenated stream of blood.

As per Association of Anaesthetists guidance [4], pressure transduction

Sugammadex is a selective neuromuscular blocking agent (NMBA) binding drug which reverses neuromuscular block induced by aminosteroid non-depolarising NMBAs. It contains a gamma-cyclodextrin structure with a hydrophilic internal cavity into which aminosteroid NMBAs are bound with high affinity, thereby inactivating them (Fig. 1) [1]. However, sugammadex can also bind to other molecules [2]. Here, we report a failure of sugammadex antagonism of neuromuscular block with rocuronium in a patient who was taking exogenous steroid hormones.

A 60-year-old man, scheduled for a robot-assisted nephrectomy, disclosed an ongoing use of steroids related to his bodybuilding practice. Self-medication included testosterone (750–1000 mg per week intramuscularly) and trestolone acetate (300 mg per week intramuscularly). Trestolone acetate is a selective androgen receptor modulator and a nandrolone derivative, 10 times more potent than testosterone (Fig. 1). Preoperative testing revealed a free testosterone blood level of 5540 pmol.l⁻¹ (reference value, 170–660 pmol.l⁻¹) and total testosterone (sex hormone binding globulin, SHBG) of 134 nmol.l⁻¹ (reference value, 6.1–27.1 nmol.l⁻¹). The patient weighed 102 kg and was 180 cm tall, with normal renal function.

Routine general anaesthesia was provided for the robotic surgery, with a total rocuronium dose of 139 mg intravenously (60 mg at induction followed by infusion of 0.2 mg.kg⁻¹.h⁻¹). The baseline train-of-four ratio (TOFr) measured with acceleromyography (Philips IntelliVue NMT, Philips, Amsterdam, The Netherlands) before rocuronium administration was 100%. At the end of surgery, TOFr was 33%, requiring administration of 2 mg.kg⁻¹ sugammadex. Ten minutes after administration of sugammadex 200 mg intravenously the TOFr had increased to 48%. After five more minutes, TOFr reached 52%. Due to this unusually slow reversal, an interaction between sugammadex and steroid hormones was suspected, and we supplemented the neuromuscular block antagonism with intravenous neostigmine 2.5 mg and glycopyrrolate 0.5 mg. Within 45 seconds of neostigmine administration, TOFr recovered to 100%.

This case describes what might be a faster-than-expected antagonistic effect of neostigmine; however, the onset of action of neostigmine administered at a recovery TOFr of 21% can be as quick as 40 sec [3]. This was consistent with our observations, particularly since neostigmine was given after sugammadex-induced recovery had already started. Our case suggests the potential for pharmacological interactions that may reduce the efficacy of sugammadex in antagonising aminosteroid NMBAs. Anabolic steroids, such as testosterone or trestolone acetate, used to increase muscle mass, are increasingly popular. It is possible that these drugs or their metabolites, which share some of the structural properties of aminoste

We present a case of inadvertent spread of local anaesthetic from combined pectoralis (PECS) 1 and 2 fascial plane blocks that resulted in an incomplete brachial plexus block. An otherwise healthy 42-year-old woman with a body mass index of 23.3 kg.m⁻² presented for unilateral mastectomy with immediate prosthetic reconstruction for breast cancer. No axillary dissection was performed. Because of service requirements, the blocks were performed at the conclusion of surgery. This may have resulted in greater cranial spread of the local anaesthetic due to surgical dissection along musculature and placement of the breast implant. Following emergence from general anaesthesia, the patient experienced numbness over the ipsilateral medial forearm extending to the little finger. Further examination with a finger-nose test revealed reduced coordination and joint proprioception of the ipsilateral arm. There was no detectable gross motor weakness. She was reviewed the following day (23 h after the blocks) by which time her symptoms had subsided entirely. We believe that this is the first documented brachial plexus block after injection of local anaesthetic into the pectoralis 1 and 2 fascial planes.

Myoclonus is a known side effect of propofol and can interfere with surgery and possibly precipitate patient injury. Here, we report a 23-year-old patient undergoing an L5 osteoblastoma resection with a predominantly propofol-based anaesthetic who developed intra-operative myoclonus. Other adjuncts included ketamine, lidocaine and fentanyl infusions. The myoclonus did not improve after deepening the anaesthetic with propofol, opioid boluses or discontinuation of the lidocaine infusion. The myoclonus ceased after reducing the propofol infusion and increasing the ketamine and opioid infusions. The remainder of the intra-operative course was uneventful. This report details our intra-operative management of propofol-induced cortical reflex myoclonus and discusses our institution's experience with treating this phenomenon.

Numerous sources of interference with Bispectral Index™ (BIS) values have been reported, including electrocautery, forced-air-warming devices, and pacemakers [1-3], electrical artefact can be misinterpreted by the BIS algorithm, resulting in misleading values [1].

Quantitative neuromuscular monitoring at the corrugator supercilii muscle is of particular utility when a patient's arms are not accessible due to surgical positioning. However, this site, involving electrodes applied to the patient's forehead, might impair BIS interpretation. We observed these changes during a steady state of general anaesthesia with a BIS Vista sensor (Covidien, Dublin, Ireland) placed on the left forehead of a patient undergoing laparoscopic abdominal surgery.

After achieving a constant effect-site concentration of propofol and an appropriate depth of anaesthesia according to BIS monitoring, and assuring neuromuscular blockade with a bolus of rocuronium, we set up a train of four (TOF) acceleromyography monitor (ToFscan®, Dräger Medical, Lübeck, Germany) with a stimulating current set at 30 mA and stimulating electrodes placed over the facial nerve, as shown in Figure 1.

Within 1 min of placing the TOF electrodes (without obtaining measurements, just with the monitor turned on), a sustained increase of between 5 and 15 points in the BIS value was observed. There were no other indications of a variation in anaesthetic depth, and there were no expected surgically induced variations in anaesthetic requirements. The BIS monitor displayed optimal signal quality (full bars), but the electromyogram (EMG) signal indicator increased slightly. Switching off the TOF monitor (maintaining connector cables applied), caused a reduction to the previously observed BIS values within 2 min.

This unexpected increase in BIS value may be explained by the fact that TOF electrode connector cables, simply attached with the monitor turned on, are a source of electrical noise [1, 3, 4]. When asked about potential interference, the manufacturer of ToFscan suggested that a probable explanation is related to frequent and periodic (every few seconds) impedance checks. Additionally, in accordance with our observations, they reported that this interference is not present when the stimulating electrodes are placed over the ulnar nerve and is no greater than that of an electric scalpel. With that in mind, using a standard digital multimeter, we measured the voltage between the two TOF electrodes and verified repeating brief rises to a maximum of 27 mV (a typical adult human electroencephalogram signal is up to 200 μV), which supports the previous explanation.

When BIS values are exceedingly high and inconsistent with clinical assessment, one should carefully confirm that no sources of interference are present. Subtle changes may go unnoticed by the BIS signal quality indicator [1]. Although variation in-between the bo

Congenital epulides, rare benign gum tumours which present at birth, pose challenges for neonatal anaesthesia due to potential airway obstruction and surgical requirements. This case report discusses successful anaesthesia for a newborn with these tumours. An oversized facemask enabled an adequate seal, and videolaryngoscopy provided good airway visualisation for orotracheal intubation. Close collaboration between anaesthesia, surgical and nursing teams resulted in safe anaesthesia and surgical removal of the epulides and an uneventful recovery.