Physician attitudes towards ventilatory support for spinal muscular atrophy type 1 in Australasia

BACKGROUND: Without ventilatory support, premature death from respiratory insufficiency is virtually universal in infants with spinal muscular atrophy type 1 (SMA1). With mechanical ventilation, however, long-term survival has been reported from numerous international centres. We aimed to characterize physician attitudes to the various forms of ventilatory support for children with SMA1. METHODS: We surveyed neurologists, respiratory physicians, clinical geneticists and intensivists from all major paediatric hospitals in Australia and New Zealand regarding their views on ventilatory management of SMA1. RESULTS: Ninety-two of the 157 (59%) physicians surveyed replied. Respondents included 16 clinical geneticists, 19 intensive care physicians, 28 neurologists and 29 respiratory physicians. Almost half (47%) opposed invasive ventilation of children with SMA1 and respiratory failure precipitated by intercurrent illness. The majority (76%) opposed invasive ventilatory support for chronic respiratory failure in SMA1. In contrast, non-invasive ventilation was felt by 85% to be appropriate for acute respiratory deteriorations, with 49% supporting long-term non-invasive ventilatory support. Most physicians felt that decisions regarding ventilation should be made jointly by parents and doctors, and that hospital Clinical Ethics Committees should be involved in the event of discordant opinion regarding further management. A majority felt that a defined hospital policy would be valuable in guiding management of SMA1. CONCLUSIONS: Respiratory support in SMA1 is an important issue with significant ethical, financial and resource management implications. Most physicians in Australian and New Zealand oppose invasive ventilatory support for chronic respiratory failure in SMA1. Non-invasive ventilation is an accepted intervention for acute respiratory decompensation and may have a role in the long-term management of SMA1. Clinical Ethics Committees and institutional policies have a place in guiding physicians and parents in the management of children with SMA1.     

Bilateral long-range interaction between right and left visual hemifield

Long-range interaction has been reported to be limited in space within a few degrees. Here, we present a new type of interaction by means of a bilateral configuration using two Gabor signals (GSs). Two horizontally oriented GSs, the first defined as a cue and the second as a probe, appeared in the right and left peripheral visual fields in mirror symmetrical regions. The detection threshold of the GS probe was found to decrease significantly up to cue-probe separations of 10 degrees tested. Since the interaction was sensitive to symmetrical locus, as well as specific to the direction of the horizontal axis, the results suggest novel long-range interaction extending toward the periphery with a mirror-symmetrical configuration. This may be acquired by neuronal communication, which directly connects bilateral receptive fields in the right and left visual cortices.     

The aetiology of idiopathic scoliosis: biomechanical and neuromuscular factors

The aetiology of adolescent idiopathic scoliosis (AIS) remains an enigma. In the literature there are two opinions: one believes a deviating growth pattern is responsible for the condition – patients with AIS tend to be growing faster/be taller – while the other opinion assumes that the growth pattern is normal, but its presence is necessary to allow the development of the scoliosis. We discuss the two stage hypothesis: the natural history of AIS involves an initial stage in which a small curve develops due to a small defect in the neuromuscular control system and a second stage during adolescent growth in which the scoliotic curve is exacerbated by biomechanical factors. Received: 4 March 1999 Revised: 27 January 2000 Accepted: 4 February 2000     

三种剂量罗库溴铵麻醉诱导的时效及其解迷走神经作用比较

目的 :比较不同剂量的罗库溴铵在全麻诱导气管插管时的起效时间、恢复时间、肌松程度及其解迷走神经作用。方法 :全麻下手术 60例 ,依罗库溴铵剂量分 3组 ,每组 2 0例 ,依次注入咪唑安定 0 2mg/kg ,异丙酚 2 0mg/kg和芬太尼 5μg/kg ,后按组注入不同剂量的罗库溴铵行全麻诱导气管插管 ,观察起效时间 ,恢复时间 ,同时观察心率、血压、心电图等心血管反应作为解迷走神经反应的指标。结果 :三组插管条件均为优等 ,注药前后无明显的心血管反应 ,起效时间 0 6mg/kg组明显长于0 9mg/kg组 ,恢复时间后者明显长于前者 ,50mg/例起效时间和恢复时间均介于前 2组间。结论 :罗库溴铵随剂量增加起效时间缩短而恢复时间延长 ,当剂量达 0 9mg/kg时其解迷走神经作用仍不明显 ,成人一律选用 50mg/例作气管插管简便可行 ,可供临床选用     

What is the Role of Sugammadex in the Emergency Department?

BackgroundSugammadex is a medication newly available to many emergency physicians. It effectively, and within minutes, reverses neuromuscular blockade in patients who have received rocuronium or vecuronium. The role of sugammadex for the reversal of neuromuscular blockade after rapid sequence intubation in the emergency department (ED) is evolving, and limited emergency medicine-specific literature exists.ObjectiveThis narrative review evaluates the role of sugammadex for the reversal of neuromuscular blockade in the ED.DiscussionThe basic pharmacology, duration of action, adverse effects, and important medication and disease interactions specific to sugammadex are well described. Case reports suggest sugammadex can reverse neuromuscular blockade to facilitate an urgent, neurologic examination by an emergency physician or consultant. Multiple case reports of failure to improve airway patency with the use of sugammadex, even when neuromuscular blockade is completely reversed, and concern for added difficulty of definitive airway management in a patient with spontaneous movement suggest that sugammadex should largely be omitted from failed or difficult airway management strategies. Instead, it is important to focus on the ability to oxygenate and ventilate, including progression to surgical airway or jet ventilation if needed.ConclusionSugammadex is an effective, rapid reversal agent for rocuronium and has the potential use to facilitate an urgent neurologic examination shortly after administration of rocuronium. Its routine inclusion in a failed or difficult emergency airway is not supported by available literature.     

Posturographic evaluation of the proprioceptive effect of ankle orthoses in healthy volunteers

This study analyses the proprioceptive effect of wearing a unilateral and then bilateral ankle orthosis on 34 healthy volunteer subjects by posturography. An elastic orthosis with a ligamentous support band was used, and evaluation was performed by a posturographic statokinesimetric platform. Three tests, one without an orthosis, one with one orthosis, and one with two orthoses, were recorded for each volunteer. The results and statistical analyses demonstrated a significant difference in the antero-posterior measurement between the test without ankle orthosis and the tests with one and with two orthoses. This study provides information about the prophylactic effect of wearing a flexible support; it appears that there are important inter-individual variations in postural equilibrium, and the wearing of prophylactic ankle orthoses should be reserved for subjects after a posturographic examination.     

Autonomic nerves and perivascular fat: Interactive mechanisms

The evidence describing the autonomic innervation of body fat is reviewed with a particular focus on the role of the sympathetic neurotransmitters. In compiling the evidence, a strong case emerges for the interaction between autonomic nerves and perivascular adipose tissue (PVAT). Adipocytes have been shown to express receptors for neurotransmitters released from nearby sympathetic varicosities such as adrenoceptors (ARs), purinoceptors and receptors for neuropeptide Y (NPY). Noradrenaline can modulate both lipolysis (via α₂- and β₃-ARs) and lipogenesis (via α₁- and β₃-ARs). ATP can inhibit lipolysis (via P₁ purinoceptors) or stimulate lipolysis (via P_2y purinoceptors). NPY, which can be produced by adipocytes and sympathetic nerves, inhibits lipolysis. Thus the sympathetic triad of transmitters can influence adipocyte free fatty acid (FFA) content. Substance P (SP) released from sensory nerves has also been shown to promote lipolysis. Therefore, we propose a mechanism whereby sympathetic neurotransmission can simultaneously activate smooth muscle cells in the tunica media to cause vasoconstriction and alter FFA content and release from adjacent adipocytes in PVAT. The released FFA can influence endothelial function. Adipocytes also release a range of vasoactive substances, both relaxing and contractile factors, including adiponectin and reactive oxygen species. The action of adipokines (such as adiponectin) and reactive oxygen species (ROS) on cells of the vascular adventitia and nerves has yet to be fully elucidated. We hypothesise a strong link between PVAT and autonomic fibres and suggest that this poorly understood relationship is extremely important for normal vascular function and warrants a detailed study.     

Novel Neuromuscular Electrical Stimulation System for Treatment of Dysphagia after Brain Injury

The purpose of this study was to compare the effects of a novel neuromuscular electrical stimulation (NMES) to the effects of conventional treatment in patients with dysphagia after brain injury. In total, 26 patients were non-randomly divided into an experimental group (n = 12) and a control group (n = 14). The experimental group received NMES intervention followed by conventional treatment, including thermal-tactile stimulation with intensive repetition of a dry-swallow task. The control group received conventional treatment without NMES. NMES at a fixed pulse duration of 50 μs and a frequency of 50 Hz was delivered over the skin areas above the motor point of the target muscles, i.e., the bilateral geniohyoid, mylohyoid/anterior belly of the digastric, and thyrohyoid muscles, using a high-voltage pulsed-current device. The two groups received 40-min treatments once a day, 5 days per week, for 8 weeks. Outcome, assessed before and 8 weeks after treatment, was evaluated with regard to the videofluoroscopic dysphagia scale (VDS), the anterior and superior displacement of the hyoid bone and larynx, and the functional oral intake scale. Both groups exhibited improvement, but the experimental group exhibited more significant improvement in the displacement of the hyoid bone and larynx, VDS-total score, and VDS-pharyngeal score than the control group did. The results suggest that NMES combined with conventional treatment is superior to conventional treatment alone in patients with dysphagia following treatment for brain injury. Further investigations are necessary to examine the effects of NMES in patients with more varied types of diseases.     

A Fatal Case Involving Propranolol and Codeine

Abstract

The dose of diazepam that reduces the mortality rate of acute intoxications with chloroquine was determined: The oral LD 50 of chloroquine (330?mg/kg) was administered and immediately thereafter diazepam was injected intraperitoneally to male and female rats at dose levels of 2.5, 7.5, 20, 55, and 148?mg/kg. An untreated group served as control. A significant decrease of the mortality rate was observed at the dose levels 7.5, 20, and 55?mg/kg with optimal effect at 20?mg/kg. This mortality rate was analysed by analysis of variance. The occurrence of two types of symptoms: convulsions and respiratory disturbances was analysed by the chi square method.