气管内吹气对急性高碳酸血症家兔血气及呼吸力学的影响

目的　探讨气管内吹气（ Ｔ Ｇ Ｉ） 对急性高碳酸血症（ Ｈ Ｃ） 家兔二氧化碳清除的效果及其对通气效率的改善作用。方法　用自行设计的 Ｔ Ｇ Ｉ装置对常规正常机械通气（ Ｃ Ｍ Ｖ） 和低通气致 Ｈ Ｃ 家兔行 Ｔ Ｇ Ｉ,分别观察两组动物在不同吹气流量（０２ Ｌ·ｍｉｎ１ 和０４ Ｌ·ｍｉｎ１） 时呼气末二氧化碳分压（ Ｐｅｔ Ｃ Ｏ２） 、血气与呼吸力学等指标的变化。结果　（１） Ｔ Ｇ Ｉ可明显降低两组动物的动脉血二氧化碳分压（ Ｐａ Ｃ Ｏ２） 水平,并能在潮气量（ Ｖ Ｔ） 降低３０ ％ 的情况下维持 Ｐａ Ｃ Ｏ２ 在正常范围, Ｔ Ｇ Ｉ降低 Ｐａ Ｃ Ｏ２ 的作用呈流量依赖性;（２） Ｔ Ｇ Ｉ使两组动物的气道压力明显增高,但 Ｈ Ｃ 组气道峰压（ Ｐｐｅａｋ） 、平台压（ Ｐｐａｕｓｅ） 水平均显著低于 Ｃ Ｍ Ｖ 组;（３） Ｔ Ｇ Ｉ使 Ｐｅｔ Ｃ Ｏ２ 明显降低,呼气阻力（ Ｒｅ） 及呼气潮气量（ Ｖ Ｅ） 显著增高,而对肺顺应性（ Ｃｓｔ） 无明显影响;（４） Ｔ Ｇ Ｉ对平均动脉压及心率无显著影响。结论　 Ｔ Ｇ Ｉ是一种简便实用的机械通气的辅助手段,它能有效地降低 Ｐａ Ｃ Ｏ２ ,并使气道压力维持在低水平。     

常用通气模式对血液动力学的影响

目的：探讨辅助控制呼吸（Ａ／Ｃ）、同步间歇指令呼吸（ＳＩＭＶ）和压力支持（ＰＳＶ）三种通气模式对血液动力学的影响。方法：对１２例危重症患者在呼吸支持最初阶段采用Ａ／Ｃ方式，并逐次改为ＳＩＭＶ和ＰＳＶ方式，每种模式持续３０ｍｉｎ，三种模式吸入氧浓度不变，利用Ｓｗａｎ－Ｇａｎｚ导管获得血流动力学参数。结果：与Ａ／Ｃ相比，ＳＩＭＶ和ＰＳＶ可降低外周循环阻力（ＳＶＲ），增加心脏指数（ＣＩ），进一步增加动脉血氧分压（Ｐａｏ２）和低的吸气峰值压（ＰＩＰ）。结论：与Ａ／Ｃ相比，ＳＩＭＶ和ＰＳＶ对血液动力学影响较小，可进一步增加组织的氧利用率     

细胞因子对树突状细胞抗肝癌作用的影响

目的研究人血树突状细胞（ＤＣ）和细胞因子ＴＮＦ,ＧＭＣＳＦ或ＩＦＮγ联合ＤＣ对淋巴因子和ＰＨＡ激活的杀伤细胞（ＬＰＡＫ细胞）体外杀伤人肝癌细胞株ＢＥＬ７４０２的影响．方法实验分为Ｌ组（ＬＰＡＫ）,Ｄ组（ＬＰＡＫ＋ＤＣ）,Ｔ１组（ＬＰＡＫ＋ＤＣ＋ＴＮＦ５０００ｋＵ／Ｌ）,Ｔ２组（ＬＰＡＫ＋ＤＣ＋ＴＮＦ５００ｋＵ／Ｌ）,Ｇ１组（ＬＰＡＫ＋ＤＣ＋ＧＭ－ＣＳＦ５００ｋＵ／Ｌ）,Ｇ２组（ＬＰＡＫ＋ＤＣ＋ＧＭ－ＣＳＦ１００ｋＵ／Ｌ）,Ｉ１组（ＬＰＡＫ＋ＤＣ＋ＩＦＮγ５００ｋＵ／Ｌ）和Ｉ２组（ＬＰＡＫ＋ＤＣ＋ＩＦＮγ１００ｋＵ／Ｌ）．每组效靶细胞比分别采用５∶１和１０∶１两种．培养４８ｈ后用中性红比色法检测细胞毒活性．结果Ｌ,Ｄ,Ｔ２和Ｔ１组的细胞毒活性依次增强,各组间差异有显著性（Ｐ＜００１）．Ｇ１和Ｇ２组均高于Ｄ组（Ｐ＜００１）,但Ｇ１,Ｇ２组间差异无显著性．Ｉ１,Ｉ２组与Ｄ组相比,也无显著性差异．随效靶比增加,各组细胞毒活性均相应增强．结论ＤＣ能增强ＬＰＡＫ细胞对肝癌细胞ＢＥＬ７４０２的细胞毒活性;ＴＮＦ或ＧＭＣＳＦ与ＤＣ联用,两者有协同作用;但与ＩＦＮγ联用,则无进一步增强作用     

卡托普利对肾血管性高血压大鼠TXA2／PGI2及血小板[Ca^2＋]i的影响

目的观察肾性高血压大鼠血浆ＴＸＡ２／ＰＧＩ２及血小板内钙的变化。方法Ｗｉｓｔａｒ大鼠手术组３０只，假手术组１０只，比较两组测定指标。结果二肾一夹型肾血管性高血压大鼠血浆ＴＸＡ２／ＰＧＩ２显著升高（Ｐ〈０．０５），血小板内「Ｃａ＾２＋」显著减少（Ｐ〈０．０１）。结论卡托普利对血小板内「Ｃａ＾２＋」ｉ的影响可能与其改善ＴＸＡ２／ＰＧＩ２比值有关。     

急性冠状动脉综合征合并糖耐量减低对纤溶系统的影响

目 的：分析急性冠状动脉综合征（ＡＣＳ）患者合并糖耐量异常对Ｄ－二聚 体（ＤＤ）含量 的 影 响。方 法：选 择１３５例住 院 治 疗 的ＡＣＳ患者。根据糖代谢情况,患者被分为单纯ＡＣＳ组（４８例）,２型糖 尿 病（Ｔ２ＤＭ）＋ＡＣＳ组（４６例）和糖 耐 量 减 低（ＩＧＴ）＋ＡＣＳ组（４１例）;同期住院健康体检者３５例作为正常对照组。测定 比 较 各 组 的浆ＤＤ水平。结 果：与正常对照组和单纯ＡＣＳ组比 较,Ｔ２ＤＭ＋ＡＣＳ组和ＩＧＴ＋ＡＣＳ组的甘油三酯水平［（１．１２±０．３９）ｍｍｏｌ／Ｌ,（１．５２±０．９２）ｍｍｏｌ／Ｌ比（２．５７±１．１７）ｍｍｏｌ／Ｌ,（２．３２±０．９６）ｍｍｏｌ／Ｌ］显著 升 高（Ｐ均＜０．０１）;与正常对照组比较,单纯ＡＣＳ组、Ｔ２ＤＭ＋ＡＣＳ组和ＩＧＴ＋ＡＣＳ组患 者 血 浆ＤＤ水平［（３６０．５０±７４）ｎｇ／ｍｌ比（７９５．２４±１３４．１０）ｎｇ／ｍｌ比（６６３．３１±１１６．０６）ｎｇ／ｍｌ,（７０２．４０±１２６．６４）ｎｇ／ｍｌ］均显 著 升 高（Ｐ均＜０．０１）;而Ｔ２ＤＭ＋ＡＣＳ组和ＩＧＴ＋ＡＣＳ组的 血 浆ＤＤ水平显著低于单纯ＡＣＳ组（Ｐ均＜０．０５）。结论：急 性 冠 状动脉综合征合并糖耐量减低患者纤溶系统功能较单纯ＡＣＳ患者 减 退。     

冠状动脉重建术后氧输送和氧耗关系的探讨

观察３０例冠状动脉旁路移植术（ＣＡＢＧ）后氧输送指数（ＤＯ２Ｉ）、氧耗指数（ＶＯ２Ｉ）及其关系。其中单纯ＣＡＢＧ１５例，伴左室室壁瘤切除１２例，心脏瓣膜替换３例。全组架１～４支桥者分别是１０、８、８、４例。结果２９例成活，１例死亡。成活组术后即刻至３小时ＤＯ２Ｉ提高１０．６％（Ｐ＜０．０５）。ＶＯ２Ｉ增高１５．８％（Ｐ＜０．０１）．术后１４小时较６小时ＤＯ２Ｉ增加１５．８％（Ｐ＜０．０１），而ＶＯ２Ｉ降低４．４％。死亡例即刻至３小时ＤＯ２Ｉ增加６．０％，ＶＯ２Ｉ却降低２９．１％，死于多器官功能衰竭。资料表明，作为ＣＡＢＧ术后正常恢复经过，早期ＤＯ２Ｉ升高的同时ＶＯ２Ｉ也升高，此时，细胞内氧化磷酸化得到改善，氧债得到清偿。氧输送和氧耗达到平衡后ＶＯ２Ｉ不再增加。可见ＣＡＢＧ术后维持满意ＤＯ２Ｉ非常重要。     

肺心病患者血浆内皮素含量变化观察分析

采用放射免疫分析法测定２８例肺心病患者及１４例正常人血浆内皮素（ＥＴ）含量，并同时作动脉血气分析及测定部分患者肺血管阻力（ＰＶＲ）、心输出量（ＣＯ）。结果：肺心病组血浆ＥＴ明显高于正常人（Ｐ＜０．０１），急性期显著高于缓解期（Ｐ＜０．０１）。血浆ＥＴ与ｐＨ、ＰａＯ２呈显著负相关（Ｐ＜０．０１），与ＰＶＲ呈显著正相关（Ｐ＜０．０１），与ＣＯ是显著负相关（Ｐ＜０．０１）。提示；低氧血症和酸血症可能是刺激血浆ＥＴ升高、引起肺血管内皮功能紊乱的重要因素；ＥＴ在肺血管阻力增加、肺动脉高压形成的病理过程中有其重要的作用。     

左旋精氨酸对糖耐量减低患者胰岛细胞早期分泌功能的兴奋作用的研究

目的　观察糖耐量减低（ＩＧＴ）患者胰岛早期分泌功能异常。方法　采用精氨酸（Ｌ－ＡＲＧ）静脉注射法对２９例ＩＧＴ患者和５４例健康者胰岛早期分泌功能进行研究。结果　ＩＧＴ组空腹胰岛素和Ｃ－肽值明显高于对照组（Ｐ＜ ０．０５或Ｐ＜ ０．０１）,胰升糖素两组间无显著性差异。经Ｌ－ＡＲＧ兴奋后,两组ＩＮＳ、Ｃ－肽和胰升糖素均在２分钟达分泌峰值,且ＩＧＴ组明显高于对照组（Ｐ＜ ０．０５或Ｐ＜ ０．０１）,经调整性别和年龄后多因素分析发现ＩＧＴ组ＩＮＳ分泌量与舒张压（ＤＢＰ）和体重指数（ＢＭＩ）均呈明显正相关（Ｐ＜ ０．０５）。结论　ＩＧＴ患者对Ｌ－ＡＲＧ的反应性增加,表现为胰岛α、β细胞的高分泌及功能紊乱。     

左旋精氨酸对糖耐量减低患者胰岛细胞早期分泌功能的兴奋作用？…

目的 观察糖耐量减低（ＩＧＴ）患者岛早期分泌功能异常。方法 采用精氨酸（Ｌ－ＡＲＧ）静脉注射法对２９例ＩＧＴ患者和５４例健康者胰岛早期分泌功能进行研究。结果 ＩＧＴ空腹胰岛素和Ｃ－肽值明显高于对照组（Ｐ〈０．０５或Ｐ〈０．０１）,胰诏纱两组间无显著性差异。经Ｌ－ＡＲＧ兴奋后,两组ＩＮＳ、Ｃ－肽和胰升糖素均在２分钟达分泌峰值,且ＩＧＴ组明显高于对照组（Ｐ〈０．０５或Ｐ〈０．０１）,经调整性别和年龄后     

高氟对人体血液生化及血脂代谢的影响观察

对暴露组相对照组各６２例进行了血Ｋ＾＋、Ｎａ＾＋、Ｃｌ＾－、Ｃａ＾２＋、ｍＧ＾２＋、ｐ＾３－、ＡＬＰ、ＴＣ和ＴＧ测定。结果显示,暴露组血Ｋ＾＋、Ｐ＾３－、ＡＬＰ、ＴＣ和ＴＧ显著高于对照组（Ｐ〈０．０１）,Ｍｇ＾２＋显著低于对照组（Ｐ〈０．０１）。暴露组中重度氟骨症与非氟骨症者上述指标也有显著性差异（Ｐ〈０．０１）。表明长期摄取过量的氟对人体血液生化及血脂代谢有明显的影响,且与氟中毒程度呈正相关。     

Cardiorespiratory effects of pressure controlled ventilation in severe respiratory failure

Cardiorespiratory values were measured in ten patients with severe respiratory failure on volume controlled and pressure controlled ventilation. Tidal volume, respirator rate, PEEP, auto-PEEP, inspiratory:expiratory ratio (1:2) and FIo2 were maintained at the same value for both ventilatory modalities. Changing from VCV to PCV was associated with significant improvements in PaO2, oxygen delivery, and tissue oxygen consumption. Peak inspiratory pressure fell. There were no significant changes in other cardiorespiratory values, such as arterial blood pressure, nor in ventilatory measurements, such as mean airway pressure, associated with the use of PCV. These results suggest that PCV may be a beneficial ventilatory modality in the treatment of severe respiratory failure since it results in improvement in arterial oxygenation, tissue oxygen delivery and utilization without any concomitant adverse effects on other hemodynamic or ventilatory factors.     

Effects of inverse ratio ventilation on cardiorespiratory parameters in severe respiratory failure.

Inverse ratio ventilation, with prolonged inspiratory times, appears to improve gas exchange and arterial oxygenation in patients with severe respiratory failure; however, in previous studies, pressure-controlled inverse ratio ventilation (PC-IRV), which uses a rapidly decelerating inspiratory flow pattern, was compared to conventional volume-controlled ventilation, which uses a constant inspiratory flow rate. Pressure-controlled ventilation (PCV), with a decelerating inspiratory flow pattern and conventional inspiratory-to-expiratory (I/E) ratios, also has been shown to produce improvement in PaO2 when compared to volume-controlled ventilation. It therefore is unknown if the potentially beneficial effects of PC-IRV are due to the reversal of I/E ratios or to the use of the rapidly decelerating inspiratory flow pattern. In order to investigate this issue, cardiorespiratory values were measured in ten patients with severe respiratory failure ventilated first with PCV, then PC-IRV, and finally with a second period of PCV. Tidal volume, respiratory rate, end-expiratory pressure, and fraction of oxygen in inspired gas (FIO2) were maintained at the same value for both ventilatory modalities. The PC-IRV was associated with significant increases in PaO2, arterial pH, and mean airway pressure. Significant decreases in pulmonary shunt fraction, PaCO2, and cardiac index were found with PC-IRV. No significant changes in tissue oxygen delivery or consumption occurred with either PCV or PC-IRV. These results demonstrate that inversion of conventional I/E ratios produces no significant improvement in the overall cardiorespiratory profile of critically ill patients. This study also suggests that the clinical utility of PC-IRV is limited except in the setting of the adult respiratory distress syndrome with hypoxemia or hypercapnia refractory to other therapeutic options.     

死腔内气体吸出技术对急性高碳酸血症犬呼吸功能及血流动力学的影响

目的 建立死腔内气体吸出技术(ASPIDS)的方法 ,并探讨ASPIDs对急性高碳酸血症(HC)杂种犬二氧化碳清除的效果及其对通气效率的改善作用.方法 将12只杂种犬分为常规机械通气(CMV)组和高碳酸血症(HC)组,每组6只.用自行设计的ASPIDS装置对两组动物行气管内吹气(TGI)和ASPIDS,分别观察两组动物在TGI(吹气流量4.0L/min)和ASPIDS(抽气流量4.0 Lmin)时呼气末二氧化碳分压(PetCO2)、血气、呼吸力学、血流动力学等指标的变化.结果 (1)ASPIDS可明显降低两组动物的动脉血二氧化碳分压(PaCO2)水平(P＜0.0001),并能在潮气量(VT)降低30%的情况下维持PaCO2在正常范围,ASPIDS对二氧化碳的清除效果优于TGI;(2)ASPIDS使两组动物的气道压力明显降低(P＜0.0001);(3)ASPIDS使PetCO2和呼气阻力(Re)显著降低,而对肺顺应性(Cst)无明显影响(P＞0.05);(4)ASPIDS对血流动力学和氧动力学指标无显著影响(P＞0.05).结论 ASPIDS是一种简便实用的机械通气的辅助手段,较TGI更能有效地降低PaCO2,并使气道压力维持在较低的水平.     

Cardiorespiratory effects of changing inspiratory to expiratory ratio during high-frequency oscillation in an animal model of respiratory failure.

To examine the effects of varying inspiratory/expiratory ratio (I/E) on cardiorespiratory function during high-frequency oscillation (HFO), 11 saline-lavaged rabbits were ventilated at I/E = 1:2, 1:1.5, 1.5:1, and 2:1 in a paired comparison to a baseline of I/E = 1:1. HFO was delivered by a SensorMedics model 3100 oscillator at a frequency of 10 Hz. Pressure amplitude and proximal mean airway pressure (PPaw) were held constant as I/E was varied from baseline to the experimental I/E. During each paired observation, PaO2, PaCO2, cardiac output, blood pressure, and distal mean airway pressure (DPaw) were measured. We found that as I/E was increased or decreased from 1:1, no significant changes in PaO2, PaCO2, blood pressure, or cardiac output occurred. We conclude that in this model, varying I/E has no significant effect on oxygenation, ventilation, or cardiovascular function.     

Reduction of peak inflation and positive end-expiratory pressure using pressure control with inverse-ratio ventilation: a case report

Pressure control with inverse-ratio ventilation (PcIRV) has been shown to reduce peak inspiratory pressure (PIP) and positive end-expiratory pressure while providing adequate oxygenation and ventilation. This case of a 39-year-old man with a perforated colon who required high PIP after surgery demonstrates the effectiveness of PcIRV in reducing PIP from 72 cm H2O to 44 cm H2O and reducing positive end-expiratory pressure from 24 cm H2O to 6 cm H2O. A maximum inverse ratio of 3:1 was established to achieve a PaO2 of 105 mm Hg and PaCO2 of 37 mm Hg. In this case, the mean airway pressure rose from 32 cm H2O with assist-control ventilation to 39 cm H2O with PcIRV at 3:1. Cardiac output decreased from 9.11 L/min to 8.35 L/min with PcIRV at a 3:1 inspiratory/expiratory ratio.     

Airway anesthesia during positive and negative inspiratory pressure breathing in man.

We have measured the effects of airway anesthesia (aerosolized 5% lidocaine) on the respiratory pattern during positive or negative inspiratory pressure in 8 resting subjects. The subjects breathed through a 600 ml dead space (peak inspiratory airway pressure, Paw = -2 cmH2O) without or with negative (approx. -5 or -10 cmH2O) or positive (approx. +5 or +10 cmH2O) inspiratory pressure, provided by a laminar flow resistance or a positive pressure source, respectively. Control measurements were performed before and after measurements with airway anesthesia. Measurements included tidal volume, respiratory frequency, ventilation, inspiratory and expiratory duration, occlusion pressure (P0.1) and end-tidal PCO2. None of the parameters measured was significantly altered by airway anesthesia, which was effective in suppressing the cough reflex. We conclude that information from lung afferents that are suppressed with the elimination of the cough reflex is not important for the breathing pattern during resting ventilation with elevated tidal volume (dead space load) and with positive or negative inspiratory pressure.     

Transdiaphragmatic pressure control of airway pressure support in healthy subjects

We designed a new servoventilator that proportionally adjusts airway pressure to transdiaphragmatic pressure (Pdi) generated by the subject during inspiration. Each cycle is triggered by either a preset Pdi increase or a preset inspiratory flow value (whichever is reached first), whereas cycling-off is flow-dependent. We evaluated the servoventilator in seven healthy subjects at normocapnia and three levels of hypercapnia (normocapnia + 3, + 6, and + 9 mm Hg) comparatively with spontaneous breathing. Triggering was by Pdi in six subjects and flow in one. At all end-tidal carbon dioxide pressure levels, time from onset of diaphragm electromyographic activity to inspiratory flow was similar with and without the servoventilator. Airway pressure increased proportionally to Pdi variation during servoventilator breathing. Flow, tidal volume, respiratory rate, intrinsic positive end-expiratory pressure, and esophageal and transdiaphragmatic pressure-time products increased significantly with hypercapnia with and without the servoventilator. Breathing pattern parameters were similar in the two breathing modes, and no differences were found for intrinsic positive end-expiratory pressure or gastric pressure variation during exhalation. Esophageal and transdiaphragmatic pressure-time products were lower with than without the servoventilator. The Pdi-driven servoventilator was well synchronized to the subjects effort, delivering a pressure proportional to Pdi and reducing respiratory effort at normocapnia and hypercapnia.     

Reintroduction of continuous negative pressure ventilation in neonates: two-year experience

Continuous negative pressure ventilation utilizes subatmospheric pressure around the thorax to improve oxygenation. It has not been routinely used since the mid-1970s. We treated 37 infants with the combination of continuous negative pressure (CNP) and intermittent mandatory ventilation (IMV), after failing to attain a PaO2 of greater than or equal to 50 torr on IMV alone. Lung diseases included pulmonary interstitial emphysema (PIE), respiratory distress syndrome (RDS), and pulmonary artery hypertension (PAH) due either to meconium aspiration syndrome (MAS) or other causes (non-MAS). All infants had evidence of severe parenchymal pulmonary disease, or pulmonary artery hypertension resulting in persistent hypoxemia and hypotension. In the PIE group, CNP was started later in the course of the disease, and both positive pressure and oxygen were maintained for a longer period. The group of infants with non-MAS PAH required CNP and positive pressure ventilation for the shortest period of time. The infants with PIE also had a greater incidence of bronchopulmonary dysplasia (BPD) and intraventricular hemorrhage (IVH). In addition, three patients with PIE died. In the non-MAS patients with PAH, no complications and no deaths occurred. The response to CNP was a rapid improvement in oxygenation in all groups with the greatest increase of PaO2 in the non-MAS PAH infants: from 30 torr prior to the initiation of CNP to 140 torr within 30 minutes. No significant changes in pH or PaCO2 occurred in any group. Significant decreases in ventilator rate, mean airway pressure (Paw) and FIO2 in peak inspiratory pressure were possible by 12 hours of CNP.(ABSTRACT TRUNCATED AT 250 WORDS)     

Leak compensation in positive pressure ventilators: a lung model study.

Leak compensating abilities of six different positive pressure ventilators commonly used to deliver noninvasive positive pressure ventilation, including the bilevel positive airway pressure (BiPAP) S/T-D and Quantum (Respironics Inc, Murrysville, PA, USA), 335 and O'NYX (Mallinckrodt Inc, St Louis, MO, USA), PLV 102 (Respironics), and Siemens Servo 900C (Siemens Inc, Danvers, MA, USA). Using a test lung model, compensatory capabilities of the ventilators were tested for smaller and larger leaks using the assist/control or timed modes. Back-up rate was 20 min(-1), inspiratory pressure was 18 cmH2O, and expiratory pressure was 5 cmH2O. It was found that even in the absence of air leaking, delivered tidal volume differed substantially between the ventilators during use of pressure-targeted modes, depending on inspiratory flows, inaccuracies in set versus delivered pressures, and inspiratory duration. Also during pressure-targeted ventilation, increasing the tI/ttot up to, but not beyond, 0.5 improved compensation by lengthening inspiratory duration, whereas use of a sensitive flow trigger setting tended to cause autocycling during leaking, interfering with compensation. Leaking interfered with cycling of the BiPAP S/T, inverting the I:E ratio, shortening expiratory time, and reducing delivered tidal volume. Volume-targeted modes achieved limited compensation for small air leaks, but compensated poorly for large leaks. To conclude, leak-compensating capabilities differ markedly between ventilators but pressure-targeted ventilators are preferred for noninvasive positive pressure ventilation in patients with substantial air leaking. Adequate inspiratory flows and durations should be used, triggering sensitivity should be adjusted to prevent autocycling, and a mechanism should be available to limit inspiratory time and avoid I:E ratio inversion.