不同通气方法对全麻俯卧位脊柱手术老年患者围术期呼吸功能的影响

目的观察不同通气方法对老年全麻俯卧位脊柱手术患者围术期呼吸功能的影响。方法选择拟在全麻俯卧位下行腰骶椎手术的老年患者60例,ASAⅠ或Ⅱ级,性别不限,年龄65~75岁,体重50~80 kg,体重指数≤25 kg/m2;采用随机法,将其分为3组,每组20例:C组(Vt:10 m L/kg)、LV组(Vt:6 m L/kg)和LV+PEEP组(Vt:6 m L/kg,PEEP:5 cm H2O)。记录麻醉前(T0)、气管插管后仰卧位机械通气10 min(T1)、气管插管后俯卧位机械通气10 min(T2)、气管插管后俯卧位机械通气60 min(T3)、气管拔管后脱氧30 min(T4)的血流动力学指标、血气分析指标及呼吸力学指标。结果三组患者HR、MAP比较差异无统计学意义(P>0.05);与LV组同时点比较,C组及LV+PEEP组机械通气期间Ppeak、Pmean较高(P<0.05),但LV+PEEP组与C组比较,差异无统计学意义(P>0.05);LV组及LV+PEEP组Cldyn明显高于同时点C组(P<0.05),但三组患者Cldyn均随着通气时间延长呈下降趋势,其中LV组与LV+PEEP组差异无统计学意义(P>0.05);在T4时点,LV+PEEP组Pa O2/Fi O2明显高于C组及LV组,A-a DO2低于C组及LV组,差异有统计学意义(P<0.05)。结论小潮气量联合低水平PEEP(6 m L/kg+5 cm H2O PEEP)通气能够有效改善全麻俯卧位脊柱手术老年患者术后氧合,提高肺的顺应性,有利于此类手术老年患者呼吸功能的恢复,而且对血流动力学无明显影响。     

Effect of ventilation rate on gradient of aerial contaminants in the confinement pig building

The principal aim of this study was to compare the aerial contaminants concentrations between the levels of ventilation rate and determine the variation pattern of aerial contaminants affected by the ventilation rate. As a result, there was not significant difference in total dust and total airborne microorganisms among three levels of ventilation rate (P>0.05) whereas the increased ventilation rate lowered the levels of respirable dust and gaseous compounds (P<0.05). Based on the results, it was concluded that the suspended gases in the confinement pig building generally followed the air streamline formed by the ventilation whereas the ventilation rate had little effect on the gradient of particulates, especially total dust, due to gravity generated by their size and weight. The findings that the concentrations of total airborne microorganisms were not also significantly different among the ventilation rates could be explained in terms of the fact that airborne microorganisms are easily adsorbed on the surface of dust particle.     

An implantable impedance pneumograph monitor for detection of diaphragm contraction and airway obstruction during diaphragm pacing

Impedance pneumography signals were characterised during diaphragm pacing using stimulating and recording electrodes placed on the abdominal surface of the diaphragm. These measurements were useful for the detection of muscle contraction without confounding effects from stimulus artifacts. Impedance pneumography signals were measured using 23 epimysial electrodes implanted in seven dogs with 1-5 experiments on each electrode. The polarity of the change in impedance associated with diaphragm pacing differed for each recording electrode and its configuration. Thirty-four of 57 cases produced increased impedance, 11 produced decreased impedance and the remaining 12 depended on the level of diaphragm activation. Impedance pneumography signals were useful for detecting complete airway obstruction. The mean difference between the impedance measured during open and obstructed airway conditions was 80% of the open airway impedance signal. The difference between open and obstructed airway impedance measurements was a mean of 2.3 times larger with a recording electrode on the same hemidiaphragm as the stimulating electrode, compared to an electrode placed on the opposite hemidiaphragm (p < 0.05, paired t test, four dogs). In addition, the differences between open and completely obstructed airways were a mean of 2.8 times larger when the second recording electrode was placed on the thorax at the fifth intercostal space, compared to the ninth intercostal space (p < 0.05, two-factor ANOVA, one dog, two replicates). It was concluded that impedance pneumograph circuitry could be incorporated into an existing diaphragm pacer using electrodes placed on the diaphragm to provide valuable measurements of the function of the device.     

High frequency jet ventilation for bilateral bullectomy

This case report describes the use of high frequency jet ventilation for resection of bilateral lung bullae. Low airway pressures reduced the risk of pulmonary barotrauma. A continuous infusion of ketamine provided acceptable anaesthesia.     

冠脉搭桥患者术前有关气管插管健康教育的效果观察

目的:探讨冠脉搭桥患者术前接受有关气管插管 机械通气的健康教育对疾病恢复的重要性.方法:对50例冠脉搭桥患者术后在气管插管期间对护理的积极配合治疗,以及气管插管不适的反应进行研究.其中A组为常规手术患者,术前接受过有关气管插管 机械通气的健康教育,B组为急症手术未接受过健康教育指导.结果:冠脉搭桥患者在气管插管 机械通气方面是否接受过术前健康教育对于术后机体对插管的依从性和配合治疗方面有显著差异.结论:有关冠脉搭桥手术的健康教育应从每一位患者着手,指导患者积极配合治疗,提高手术疗效.     

通气时间对呼吸机相关肺炎中β-防御素-2表达的影响

目的本研究观察大鼠肺组织β-防御素-2（BD-2）的基因和蛋白质在24h和48h两种机械通气时间的呼吸机相关肺炎（VAP）模型中表达水平。方法健康清洁级雄性成年SD大鼠随机分成24h通气组（n=29）和48h通气组（n=29）。两组大鼠分别在机械通气24h和48h后，从气管导管中注入1mol／L浓度的铜绿假单胞菌0．2mL复制VAP模型。采用RT—PCR和Western blot技术测定实验大鼠BD-2 mRNA和蛋白质表达的水平变化。结果48h组重度肺组织病理变化为66．7％，显著性高于24h组的28．6％（x^2=6．11，P=0．013）。48h组细菌血培养阳性率为62．5％，明显高于24h组的33．3％（x^2=4．09，P=0．043）。24h组5d存活率为60％，48h组为0（x^2=4．29，P=0．038）。两组接种细菌3h内BD-2 mRNA表达差异无显著性意义，24h组6h后表达上调水平显著高于48h组，并于12—24h时BD-2基因表达水平达峰值。结论随着机械通气时间延长，VAP大鼠中BD-2基因和蛋白质表达上调水平的明显下降，可能是更长时间机械通气易发生VAP的重要因素之一。     

Robust computer algorithm for detecting breaths in noisy ventilatory waveforms from infants

A computer-based algorithm to detect tidal breathing in long-term studies with little operator intervention is described. Recognition relies on matching the tidal signals to a set of three templates. A major consideration in the algorithm's design was its ability to detect, and, in some instances, to compensate for aberrations in the inspiratory/expiratory profiles. A test on a breath-by-breath basis of a sample of over 200 breaths in both quiet and active sleep in newborn infants showed that there was no significant difference between the algorithm-derived values for inspiratory and expiratory volumes and breath duration compared with those measured manually.     

Emergency adenotonsillectomy for acute postoperative upper airway obstruction

Peri-operative acute upper airway obstruction may be life-threatening. A case is reported of a child with severe adenotonsillar hypertrophy who developed acute upper airway obstruction after a routine surgical procedure and required emergency adenotonsillectomy. The importance of pre-operative assessment is stressed.     

密闭式吸痰管在机械通气病人气道护理中的应用

用循证医学的方法探索密闭式吸痰管应用在机械通气病人气道护理中的利弊。提出临床问题后,用主题“Endotracheal and Closed suction”检索Cochrane CDSR,ACP Journal Club,DARE,CCTR(OVID平台)、Medline、中国学术期刊全文数据库(CNKI)获得相关证据。吸痰时使用密闭式吸痰管,可明显减轻由吸痰引起的并发症症状,从而降低病人对吸痰的恐惧程度,避免由吸痰导致的不良事件的发生。     

Measurement of CO2 response with the breath-by-breath automatic acquisition of the breathing pattern and occlusion pressure

Objective. Our objective is to present a methodology for the automated acquisition and storage of BP and P_0.1 during a CO₂ rebreathing test.Methods. The system consists of a microcomputer with additional circuits and an automatic electronically controlled valve to occlude the inspiratory airway. Data collection and data processing are separate programs. Airway pressure and flow are digitized at a 100-Hz rate, whilePetCO₂ is determined and P_0.1 is measured on a breath-by-breath basis. Off-line processing calculates the BP variables, generates a correlation matrix (Ve/PetCO₂,Ttot/PetCO₂,Ti/PetCO₂,Te/PetCO₂, [Vt/Ti]/PetCO₂, [Ti/Ttot]/PetCO₂, P_0.1/PetCO₂), and edits graphic data. The accuracy of the volume and pressure measurements was tested by comparing known volumes provided by a syringe (n=100) and a series of pressures controlled by a water manometer (n=41) on the one hand, with volumes and pressures measured by the device. The accuracy of the time intervals and P_0.1 was assessed by comparing in 10 healthy subjects the values measured manually on a graphic recording with those provided by the device (n=170).Results. Volumes: V_measured=0.99×V_controlled,r=0.99,p<0.001. Pressures: P_measured=0.97×P_controlled+0.09,r=0.98,p<0.001. Inspiratory time:Ti _automatic=0.91×Ti _graphic+0.22,r=0.93,p<0.001. Expiratory time:Te _automatic=0.93×Te _graphic+0.34,r=0.95,p<0.001. Occlusion pressure: P_{0.1 automatic}=0.95×P_{0.1 graphic}+0.62,r=0.94,p<0.001. Reproducibility was assumed to be represented by the intraindividual coefficient of variation of the CO₂ response. The comparison of an automatic breath-to-breath method with a graphic manual recording revealed significantly less variability with the former (Ve/PetCO₂: 15.2±4.5% vs 22.5±6.3%,p<0.01; P_0.1/PetCO₂: 8.3±4.3% vs 19.7±7.2%,p<0.001; [Vt/Ti]/PetCO₂: 9.1±3.5% vs 14.5±5.3%,p<0.05).Conclusion. Our automated acquisition and storage of waveforms and breath-by-breath determination of BP and P_0.1 provide an easy and thorough analysis of the respiratory response to CO₂ and decrease the variability of the results.