Biophysique de l’échauffement cutané par conduction et par radiation: implications pour l’étude différentielle des afférences Aδ et C chez l’homme

Résumé  Pour caractériser les différents types de récepteurs cutanés thermosensibles, il para?t essentiel de définir les conditions de stimulation thermique, plus précisément les paramètres physiques du stimulus et les propriétés thermophysiques de la peau. Trois méthodes expérimentales de transfert de chaleur à la peau sont étudiées. La première représente la situation idéalisée d’une peau à température initiale constante soudainement mise en contact avec une sonde thermique maintenue à température constante. La seconde méthode représente la situation où la peau est mise en contact avec une sonde dont la température cro?t de manière linéaire à partir d’une température initiale. La troisième méthode représente la situation où la peau est exposée à une source d’énergie calorifique radiante ayant une densité de puissance constante. Les résultats de ces études illustrent que le fait de négliger la relation entre les paramètres physiques du stimulus et les propriétés thermophysiques de la peau peut conduire à des observations en apparence paradoxales. Par contre, en contr?lant ces paramètres de manière appropriée, l’expérimentateur peut faire varier de manière considérable le délai entre l’arrivée des informations en provenance des récepteurs A∂ et C au niveau du premier relais spinal. Cela lui permet ainsi d’étudier leurs interactions. Finalement, il appara?t qu’une source radiante dans le lointain infra-rouge (laser CO₂) approte des avantages certains sur les stimulateurs calorifiques conventionnelles.

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Summary  To characterise cutaneous thermoreceptors, it seems essential to define exactly the conditions of thermal stimulation, more precisely the physical parameters of the stimulus and the thermophysical properties of the skin. Three experimental procedures of heat transfer to the skin are examined. The first procedure represents the ideal situation of a skin at a given base temperature suddenly put in contact with a thermode at a fixed temperature. The second procedure represents a situation in which the skin is put in contact with a thermode producing a linear heat ramp. The third procedure represents a situation in which the skin is exposed to a radiant heat source of constant energy density. The results of these studies show that neglecting the relationship between parameters of the thermal stimulus and the thermophysical properties of skin may lead to apparently paradoxical observations. In contrast, when properly controlled, these parameters can allow to vary considerably the delay between the arrival at the first spinal relay of information conveyed by A∂ and C-fibres and as a consequence allow to study their interactions. Finally, it seems that a source of radiation in the far infrared (CO₂ laser) offers several advantages over conventional heat stimulators.

Texte présenté lors du Congrès SFD-SOFRED des 15–17 juin 2000.     

四氢巴马汀对大鼠心肌缺血再灌注损伤的保护作用

目的:探讨四氢巴马汀(l-THP)对大鼠心肌缺血再灌注损伤的保护作用。方法:Wistar大鼠24只,分为假手术组、模型组和l-THP治疗组,结扎大鼠冠状动脉左前降支30min再灌注120min造成心肌缺血再灌注损伤模型,分别于缺血30min、再灌注30min、60min、90min、120min观察l-THP对大鼠心功能、心肌酶学和脂质过氧化的影响。结果:l-THP能够对抗心肌缺血再灌注损伤引起的左心室内压(LVSP)、左心室内压最大上升与下降速率(±dp/dtmax)下降,左心室舒张末期压力(LVEDP)的升高,并能够稳定心肌组织Na -K -ATPase和Ca2 -Mg2 -ATPase活性,降低丙二醛(MDA)含量和增高超氧化物歧化酶(SOD)的活性。结论:四氢巴马汀(l-THP)对大鼠心肌缺血再灌注引起的心功能降低具有明显的保护作用,其机制可能与改善能量代谢障碍和抑制自由基生成或清除氧自由基作用有关。     

The practical management of artifact in computerised physiological data

Computerised physiological data contains artifact that needs to be identified and possibly removed. Whilst computers may eventually satisfactorily perform this function, at present only manual removal is possible for the majority of intensive care computer groups. We assessed the effects of artifact and its removal on the physiological data of 3 patients. Artifact was manually removed from 7 days of data in 4 parameters (heart rate, respiratory rate, systolic blood pressure [sbp] and transcutaneous oxygen [tcpO2]) by 3 independent observers. Six hour time periods were analysed. Median and mean values before and after the manual removal of artifact were compared. Overall. 6.5% of data was removed as artifact. This was greatest for tcp02 (9.9%) and sbp (10.6%), with smaller amounts for respiratory rate (2.8%) and heart rate (2.4%). Sbp showed a marked difference in the amount of data removed between patients, whereas tcp02 data contained quite large volumes of artifact, but this was fairly consistent between patients, Removal of artifact affected mean values more than median values. One observer considered that both physiological and non-physiological artifact should be removed, whereas the other two observers removed only non-physiological artifact. Agreement in results between the latter was good. Our results suggest that interobserver variability should have a minimal effect on values, once rules identifying the type of artifact to be removed are agreed. Removal of artifact did not have a clinically significant effect on results, but may be an important consideration in the statistical analysis of computerised physiological data.Abbreviations CPTM computerised physiological trend monitoring - tcp02 transcutaneous pressure of oxygen - sbp systolic blood pressure     

Radiation‐induced angiosarcoma of the breast: A review

Angiosarcoma is a rare, aggressive malignant vascular neoplasm with poor prognosis that has a predilection for skin and superficial soft tissue. It can arise spontaneously or in association with factors like chronic lymphedema or radiation therapy. Radiotherapy used to treat invasive breast tumors is a known risk factor for the development of the so‐called radiation‐induced angiosarcoma (RIAS), a condition that has been described in the literature with increasing frequency. Radiation‐induced angiosarcoma of the breast usually arises on the previously irradiated skin area several years after radiotherapy and presents as painless multifocal erythematous patches or plaques similar to a hematoma. Cutaneous biopsy is essential for the diagnosis. Histologically, RIAS is characterized by irregular anastomosing vessels lined by endothelial cells showing nuclear atypia. Treatment is mostly surgical, and mastectomy with negative margins is considered the standard procedure. However, recurrences are common, and an approach combining surgery, chemo‐ and radiotherapy may be more effective. The purpose of this study is to review the most recent medical literature on RIAS of the breast, with emphasis on its pathophysiology, clinical and histological features and current treatment options.     

Anesthetic implications of a pediatric patient with stiff skin syndrome: A case report

Stiff skin syndrome is a rare genetic disorder that is present in infancy or early childhood. It is characterized by hard, inflexible skin and limited joint mobility making anesthetic management of these patients challenging. Their limited neck flexibility and chest wall rigidity make intubation and mask ventilation difficult. Intraoperative positioning can be challenging due to joint contractures and potential entrapment peripheral neuropathy. Even though peripheral intravenous access can be relatively easy, central venous cannulation may be problematic due to the hard skin overlying the entry sites. Our case report details the anesthetic management and considerations of a pediatric patient with stiff skin syndrome.     

A pilot multi‐centre prospective randomised controlled trial of RECELL for the treatment of venous leg ulcers

Venous leg ulcers (VLUs) have a significant impact on approximately 3% of the adult population worldwide, with a mean NHS wound care cost of £7600 per VLU over 12 months. The standard care for VLUs is compression therapy, with a significant number of ulcers failing to heal with this treatment, especially with wound size being a risk factor for non‐healing. This multicentre, prospective, randomised trial evaluated the safety and effectiveness of autologous skin cell suspension (ASCS) combined with compression therapy compared with standard compression alone (Control) for the treatment of VLUs. Incidence of complete wound closure at 14 weeks, donor site closure, pain, Health‐Related Quality of Life (HRQoL), satisfaction, and safety were assessed in 52 patients. At Week 14, VLUs treated with ASCS + compression had a statistically greater decrease in ulcer area compared with the Control (8.94 cm² versus 1.23 cm², P = .0143). This finding was largely driven by ulcers >10 to 80 cm² in size, as these ulcers had a higher mean percentage of reepithelialization at 14 weeks (ASCS + compression: 69.97% and Control: 11.07%, P = .0480). Additionally, subjects treated with ASCS + compression experienced a decrease in pain and an increase in HRQoL compared with the Control. This study indicates that application of ASCS + compression accelerates healing in large venous ulcers.     

Nurses are research leaders in skin and wound care

The World Health Assembly declared 2020, the International Year of the Nurse and the Midwife. Recent editorials and commentaries support the leading role of nurses and midwives as frontline caregivers emphasizing the need to invest in the nursing workforce worldwide to meet global health needs. Today nurses are also leaders in research and one example is skin and wound care. In order to reflect on the contribution of nurses as researchers we conducted a systematic review of published articles in five international leading wound care journals in the years 1998, 2008 and 2018. We aimed to determine the type of research publication and percentage of nurses as first, second or senior authors. The place in the authorship was selected as indicative of leadership as it implies responsibility and accountability for the published work. Across the years 1998, 2008 and 2018, 988 articles were published. The overall proportion of nurse‐led articles was 29% (n = 286). The total numbers of articles increased over time and so too did the nurse‐led contributions. Nurse‐led research was strongest in the design categories ''cohort studies'' (46%, n = 44), ''systematic reviews'' (46%, n = 19), and ''critically appraised literature and evidence‐based guidelines'' (47%, n = 55).Results of this review indicate that, in addition to the crucial clinical roles, nurses also have a substantial impact on academia and development of the evidence base to guide clinical practice. Our results suggest that nurse led contributions were particularly strong in research summarizing research to guide skin and wound care practice.