不同类型心脏患者心内直视手术期间呼气末CO2分压与动脉血CO2分压及其差值的变化

目的探讨不同类型心脏患者心内直视手术期间呼气末二氧化碳分压（PETCO2）与动脉血二氧化碳分压（PaCO2）的相关性及二者差值[P（a-ET）、CO2]的临床意义。方法45例患者分成3组，每组15例。A组：左向右分流组；B组：无分流组；C组：右向左分流组。3组分别于术前（T0）、插管后15min（T1）、手术开始时（T2）、转流前（T3）、转流停止后15min（T4）、术毕时（T5）共6个时点，用旁气流法监测PETCO2，同时抽动脉血测定PaCO2，应用直线回归分析3组各时点PETCO2与PaCO2的相关性，同时计算并分析各组不同时点的P（a-ET）CO2。结果（1）A组、B组各时点PETCO2与PaCO2呈正相关，A组r为0．70—0．85（P〈0．01），B组r为0．71—0．79（P〈0．01）；C组麻醉开始至转停后PETCO2与PaCO2均无相关（0．46—0．54，P〉0．05），而到术毕时则呈正相关（r=0．66，P〈0．05）。（2）3组患者转流前的P（a-ET）CO2变化不大，停转流后A组、B组P[a-ET）CO2增加，其中以A组增加较明显（P〈0．01），而C组P（a-ET）CO2显著减少（P〈0．05）。结论无分流或左向右分流心脏患者在体外循环转流前后PETCO2与PaCO2的相关性较好；右向左分流心脏患者转流前的相关性较差，心内畸形纠正后其相关性可发生变化。P（a-ET）CO2在不同的心脏患者之间差异较大，必须与PaCO2相结合，才能正确指导临床。     

Near‐infrared spectroscopy determined brain and muscle oxygenation during exercise with normal and resistive breathing

To elevate effects of carbon dioxide (CO₂) retention by way of an increased respiratory load during submaximal exercise (150 W), the concentration changes of oxy‐ (ΔHbO₂) and deoxy‐haemoglobin (ΔHb) of active muscles and the brain were determined by near‐infrared spectroscopy (NIRS) in eight healthy males. During exercise, pulmonary ventilation increased to 33 (28–40) L min^–1 (median with range) with no effect of a moderate breathing resistance (reduction of the pneumotach diameter from 30 to 14 and 10 mm). The end‐tidal CO₂ pressure (P_ETCO ₂) increased from 45 (42–48) to 48 (46–58) mmHg with a reduction of only 1% in the arterial haemoglobin O₂ saturation (S_aO ₂). During control exercise (normal breathing resistance), muscle and brain ΔHbO₂ were not different from the resting levels, and only the leg muscle ΔHb increased (4 (–2–10) μM , P < 0.05). Moderate resistive breathing increased ΔHbO₂ of the intercostal and vastus lateralis muscles to 6 ± (–5–14) and 1 (–7–9) μM (P < 0.05), respectively, while muscle ΔHb was not affected. Cerebral ΔHbO₂ and ΔHb became elevated to 6 (1–15) and 1 (–1–6) μM by resistive breathing (P < 0.05). Resistive breathing caused an increased concentration of oxygenated haemoglobin in active muscles and in the brain. The results indicate that CO₂ influences blood flow to active skeletal muscle although its effect appears to be smaller than for the brain.     

Ventilatory and upper-airway resistance responses to upper-airway cooling and CO2 in anaesthetised rats

The effects of upper airway (UA) cool air and CO₂ on breathing and on laryngeal and supraglottic resistances were studied in anaesthetised rats breathing spontaneously through a tracheostomy. Warm, humidified air containing 0, 5 and 9–10% CO₂ and cool, room-humidity air were delivered at constant flow to either the isolated larynx to exit through a pharyngotomy or to the supraglottic UA to exit through the mouth and/or nose (nose open or sealed). Spontaneous tracheal airflow and UA airflows, temperatures and pressures were recorded. CO₂ had no effect on breathing but caused a slight increase in laryngeal resistance which was abolished by cutting the superior laryngeal nerves (SLN). Cool air caused a decrease in respiratory frequency and/or peak inspiratory flow when applied to the isolated larynx or to the supraglottic airway with the nose closed. These effects were abolished by SLN section. With the nose open, the ventilatory inhibition was not abolished by SLN section. Cool air also caused substantial decreases in laryngeal and supraglottic resistances which were attenuated by SLN section and which persisted following recurrent laryngeal nerve section. In conclusion, whilst UA cooling inhibits breathing and decreases UA resistances, UA CO₂ has minimal effects.     

Laser induced thermal injury of rabbit cornea and treatment with anti-inflammatory agents

A moderately severe thermal injury of the central cornea of 48 Dutch-belted rabbit eyes was produced with a carbon (CO₂) laser. The lesions were photographed with a slit lamp (SL) camera immediately following the injury and at 1, 2, 4, 7, 14, 21, 30 and 60 days after the exposure. Lesion size, opaqueness, and depth were graded clinically by SL biomicroscopy at the same intervals. No significant differences were found (p 0.05) between groups of eyes treated with flurbiprofen (0.03%), prednisolone acetate (1%), and vehicle control four-times-a-day for three weeks following injury. Additionally, eyes were studied histopathologically at 3 and 60 days following injury by light and transmission electron microscopy, and clinically at 30 and 60 days by endothelial specular microscopy. Important clinical and histopathological findings included coagulative necrosis of the corneal epithelium, epithelial sloughing, fusion of stromal collagen, stromal edema and inflammatory cell infiltration, stromal scar formation, corneal thinning, endothelial hyperplasia and metaplasia, fibrinous anterior chamber reaction with hypopyon, and retrocorneal fibrous membrane formation.     

氯化钛白氧化反应器壁结疤机理

利用预燃烧直管反应器,研究氯化钛白氧化反应器内的结疤机理。氧化反应器内结疤支要起因子氧化过程生成的超细TiO2颗粒在反应器壁的沉积和烧结,反应器壁面温度越高结疤速率越快。当反应器壁面温度较低时,靠近壁面为ＴiO2颗粒堆结层,而告气体相主体的疤层发生了部分烧结。反应温度升高、反应物浓度增大时,结疤速度增大;壁面状态对结疤速率影响不大。     

A capnography and transcutaneous CO2 profile of bariatric patients during early postoperative period after opioid-sparing anesthesia

BackgroundNoninvasive monitoring of partial pressure of carbon dioxide can be accomplished indirectly with capnography (P_ETCO₂) or with transcutaneous carbon dioxide monitoring (P_TCCO₂). The use of capnography has been shown to offer an advantage over pulse oximetry alone in the early detection of adverse respiratory events when supplemental oxygen is administered. Furthermore, capnography allows for the monitoring of various respiratory measures, including end-tidal carbon dioxide, respiratory rate, tidal volume, and changes in breathing patterns. Transcutaneous CO₂ also closely approximates arterial CO₂ values, but is not as easy to monitor for prolonged periods. The purpose of this study was to examine the usefulness of capnography and of transcutaneous carbon dioxide monitoring in patients recovering from obesity surgery at high risk of developing postoperative obstructive sleep apnea.MethodsIn a prospective observational study, 64 bariatric surgery patients at risk of developing obstructive sleep apnea were monitored in the postanesthesia care unit (PACU) with either capnography alone (31 patients) or capnography plus transcutaneous carbon dioxide monitoring (33 additional patients) every 3–5 minutes for the duration of their recovery. Primary endpoints included end-tidal and transcutaneous carbon dioxide, peripheral oxygen saturation, respiratory rate, pain scores, and incidence of adverse respiratory events.ResultsAlthough no adverse pulmonary events were observed, capnography detected several patients who experienced short periods of respiratory apnea while maintaining pulse oximetry readings within normal limits. Transcutaneous values were slow to change and averaged 4.5 ± 5.5 mm Hg (P < .05) higher than corresponding end-tidal measurements.ConclusionsThese results indicate the capabilities of both these noninvasive techniques for postoperative monitoring. Capnography acutely monitors changes in respiration, whereas transcutaneous monitoring more accurately reflects arterial CO₂ levels.     

Effective improvements to the live-attenuated Newcastle disease virus vaccine by polyethylenimine-based biomimetic silicification

Live and killed vaccines impart a significant role in preventing of Newcastle disease (ND) in China. Vaccine efficacy could be ameliorated by improving vaccine-induced cellular immunity and antibody persistency. Previous studies substantiated the potency of silicon dioxide (SiO₂) in the control-release of drugs and as a vaccine adjuvant, and polyethylenimine (PEI) merits as a mucosal adjuvanticity with electro-positivity. The present study employed SiO₂ and PEI to prepare biomimetic silicon mineralized nanoparticle G7M@SiO₂-PEI and microparticle (SiO₂ + PEI)@G7M vaccines of G7M, a candidate for live attenuated vaccine of genotype VII Newcastle disease virus (NDV). The zeta potential experiment confirmed the significant increase in the average zeta potential of the nanoparticle G7M@SiO₂-PEI and microparticle (SiO₂ + PEI)@G7M relative to G7M before mineralization. The results of RT-qPCR revealed more than 99% mineralization efficiency of the G7M@SiO₂-PEI and (SiO₂ + PEI)@G7M. The morphology detected by transmission electron microscopy reported that the diameters of G7M@SiO₂-PEI were similar to those of G7M, while for (SiO₂ + PEI)@G7M, it was about five times larger than that of G7M. Silicon was detected on the surface of both mineralization particles, except for G7M, as observed from the elemental distribution detected by elemental mapping and energy dispersive X-ray spectrogram. Indirect immunofluorescence assays validated that mineralization virus have replicated ability in BHK-21F cells. In vivo experiments revealed higher than 5.50 log₂ of antibody in nanoparticles G7M@SiO₂-PEI group until 10-week post-vaccination, and significant proliferation of antigen-specific CD3⁺CD4⁺ in nanoparticles G7M@SiO₂-PEI immunized group corroborated improved cellular immune responses. Vaccines provided full protection to the immunized chickens, whereas all the chickens receiving mock immunizations succumbed to the disease. Overall, our study concluded the efficacy of biomimetic mineralization of live attenuated vaccine in nanoparticles to improve humoral and cellular immune responses.     

单肺通气时肺内分流与PETCO2的相关性研究

目的：研究单肺通气时PETCO2和Qs/Qt之间的关系。方法：选择28例择期开胸手术的患者分别于TLV 20min、OLV 5min、15min、30min、60min测动脉血和混合静脉血气并同时记录PETCO2,计算Qs/Qt,进行统计学处理。结果：OLV时不同时段PETCO2、PaCO2、Qs/Qt比TLV时增大(P＜0.05),TLV时PETCO2与Qs/Qt不相关(r=-0.0230,P=0.9077)。OLV时PETCO2与Qs/Qt相关(r=0.4739,P=0.00001),其直线回归方程为y=3.4862+0.0147x(y=PETCO2,x=Qs/Qt)。结论：OLV时PETCO2与Qs/Qt呈直线相关,PETCO2随Qs/Qt增加而增大。     

ClO_2毒性研究

ClO_2是一种可以代替液氯的新型消毒剂。本文通过金鱼毒性实验,确定了ClO_2用于饮水消毒的安全浓度;通过小白鼠急性经口毒性实验,确定了ClO_2属实际无毒型水处理剂。     

Monitoring during paediatric cardiac anaesthesia

Monitoring of paediatric anaesthesia has become increasingly more complex in recent years and this is particulary true of cardiac anaesthesia. The purpose of this review is to give a comprehensive update of published material related to both routine and specialized cardiac monitoring. Routine monitoring can be particularly affected by the alterations of cardiac rhythm, blood flow, cardiac output and oxygenation which result from the congenital heart abnormalities themselves, the type of surgery undertaken and the effects of cardiopulmonary bypass. The use of specialized monitoring is becoming more widespread, particularly in the areas of cerebral function, mixed venous oxygenation, cardiac output measurement and coagulation. In the last five years, with the development of smaller probes, a great deal has been published on transoesophageal echocardiography. The use of the current monitors of cerebral function still remains controversial despite the need for a monitor of adequate brain perfusion, reflecting the need for a great deal of further research in this area. This review will concentrate on particular areas which have seen the most profound changes and on monitoring that may form the standards of tomorrow. Finally, amongst all the technology, it should not be forgotten that the most important clinical monitor is the bedside clinical monitoring of the physicians themselves. Depuis quelques années, le monitorage de l’anesthésie pédiatrique devient déplus en plus complexe et tout particulièrement en anesthésie cardiaque. L’objectif de ce travail consiste à passer en revue la littérature actuelle qui traite du monitorage usuel et spécialisé. Le monitorage usuel peut être influencé par les modifications de la fréquence cardiaque, du courant sanguin, du débit cardiaque et de l’oxygénation provoqués par les anomalies cardiaques congénitales, du type de chirurgie et des retentissements de la circulation extracorporelle. L’utilisation du monitorage spécialisé est de plus en plus répandu et concerne particulièrement la circulation cérébrale, l’oxygénation du sang veineux mêlé, la mesure du débit cardiaque et la coagulation. Au cours des cinq dernières années, le développement de sondes plus petites a généré de nombreuses publications sur l’échocardiographie transoesophagienne. L’utilisation des moniteurs actuels de la fonction cérébrale demeure sujet à controverse bien qu ’un moniteur de perfusion cérébrale adéquat demeure toujours aussi essentiel, confirmant ainsi le besoin de recherches supplémentaires sur ce sujet. Ce survol se portera spécialement sur les champs d’activités qui ont connu les changements les plus profonds et sur le monitorage qui établira les standards du futur. Finalement, au milieu de cette technologie, il ne faut jamais oublier que le moniteur clinique le plus important se trouve au chevet du malade en la personne du médecin.