Pathophysiological aspects of predominant preload lowering on pulmonary circulation, gas exchange, and the biventricular function in patients with chronic obstructive lung disease

A group of 21 patients with various degrees of chronic obstructive pulmonary disease underwent radionuclide ventriculography with hemodynamic monitoring to assess the extent to which pulmonary artery pressures and pulmonary vascular resistance can be lowered by the vasodilator molsidomine. Molsidomine (N-carboxy-3-morpholino-sydnonimin-ethylester) is similar to nitroglycerin in its mode of action. After hemodynamic and radionuclide data acquisition, at rest and during submaximal exercise in the steady state, 2 mg molsidomine was injected intravenously. Rest and exercise measurements were repeated 45 min after molsidomine injection. In patients with mild to moderate disease (group 1), pulmonary artery resting pressures decreased by 12% (p less than 0.05) at rest by 22% (p less than 0.01) during exercise after the administration of the drug. Total pulmonary resistance during exercise decreased significantly (p less than 0.01) as a result of marked decrease of pulmonary artery pressure (PAP) compared with a minimal decrease in cardiac index (CI). In patients with severe disease (group 2), only the resting values of PAP decreased while the relationship between pressure and flow was unchanged. During the exercise period, the preload parameters of the right and left ventricles decreased by an average of 30%. With regard to gas exchange, only the arterial PO2 at rest decreased slightly but significantly (p less than 0.05) after molsidomine, while the coefficient of oxygen delivery was not affected by the drug. However, in four patients arterial PO2 was markedly reduced by the drug. Right ventricular ejection fraction increased significantly (p less than 0.01) both at rest and during exercise in group 1 and during exercise in group 2 after administration of molsidomine.(ABSTRACT TRUNCATED AT 250 WORDS)     

烧伤家兔血液流变学变化与血气分析的观察

在家兔左腿背侧部与腹部以100℃电烙铁造成10％面积2度烧伤,腹部烧伤占1/2。烧伤后血压持续下降。血浆比粘度在2h内持续增加,全血比粘度在1h内呈现增高,2h后为下降。pH与paCO_2烧伤后下降。PaO_2先下降后升高,这升高现象不同于临床所见。BE_5 1h后负值增大。实验动物在烧伤后3～4h死亡。     

Use of long catheters for multipatient anesthetic monitoring at high respiratory frequencies

Anesthetic gases from several patients can be monitored simultaneously with a centrally located mass spectrometer. Such monitoring requires catheters from patient to spectrometer that are several meters long. Scamman (J Clin Monit 1988;4:227–229) found that when the respiratory frequency is high, as with infants, the CO₂ signal from the patient is unacceptably distorted during passage down the catheter. This is due to Taylor dispersion of the input signal. An outline of the theory of Taylor dispersion is given. The equations describe the interaction between the velocity distribution (which, in laminar flow, is parabolic) and the radial diffusion of CO₂. This interaction keeps a tracer signal together in a pulse, as it moves down the tube with themean velocity, spreading somewhat as it proceeds. How much does an initially sharp signal become blurred? The spread of such a signal when it reaches the detector, measured in time, can be expressed in various ways. Measurement is complicated, however, by the fact that the gas pressure may fall by as much as a factor of 10 along the line. The resultant expansion and acceleration of the gas cannot be ignored. A full treatment of this complication is given elsewhere, but the following simple equation is described: {ie237-1} Typically, the spread time is up to a quarter of a second for catheters of 50 m, such as used by Scamman. This is comparable with the period of CO₂ rise and fall for infants and explains the serious distortion in wave form that Scamman found. Some distortion can be eliminated by reducing R to 0.1 or less, but the extent of this improvement is small. Ideally, for fast-breathing patients, the catheter length should be reduced to 20 m or less, if possible.     

小鼠眼球中脂肪酸组成分析

用气相色谱法分析了小鼠眼球中脂肪酸的组成及百分含量。分离是在２５ｍ×０．２５ｍｍＰＥＧ－２０Ｍ熔融石英毛细管柱内进行，眼球中１２种主要饱和及不饱和脂肪酸得到了定性和定量。本实验可为有关眼疾病的治疗、预防及生化方面的深入研究提供有意义的信息。     

高频喷射通气结合胸壁挤压对组胺致肺损伤犬呼吸循环功能的影响

以高频喷射通气结合胸壁挤压（ＨＦＪＶ＋ＣＷＣ）为通气模式，观察其对组胺致肺损伤犬呼吸循环功能的影响，并与单纯高频喷射通气（ＨＦＪＶ）进行比较。结果表明：与ＨＦＪＶ相比，ＨＦＪＶ＋ＣＷＣ时的功能残气量（ＦＲＣ）、ＰａＣＯ＿２和ＰＣＯ＿２均显著降低（Ｐ＜０．０１），肺泡通气量（Ｖ＿Ａ）和二氧化碳排出量（ＣＯ＿２）均显著增高（Ｐ＜０．０１），每分呼出气量（Ｖ＿Ｅ）、ＰａＯ＿２、ＰＣＯ＿２、吸气峰压（ＰＩＰ）、平均气道压（Ｐａｗ）、呼气末压（ＥＥＰ）、ＨＲ、平均动脉压（ＭＡＰ）、肺动脉压（ＰＡＰ）和肺毛细血管楔压（ＰＣＷＰ）均无显著变化（Ｐ＞０．０５）。提示：ＨＦＪＶ＋ＣＷＣ除保留单纯ＨＦＪＶ时气道开放、气道低压、良好的血液氧合、不影响循环功能等特点外，还具有增加呼气动力，改善肺泡通气，显著促进ＣＯ＿２排除等优点。     

Treatment of pigment epithelial detachments due to age-related macular degeneration with intra-ocular C3F8 injection*

Purpose: To flatten pigment epithelial detachments (PED) cue to age-related macular degeneration in an attempt to visualize the underlying choroidal neovascularization by fluorescein angiography (FA) and reveal a treatment target. Methods: Nine patients with PED received intravitreal gas injections via the pars plana and postured face down. Fluorescein angiograms were obtained before and after gas injection. In two patients, retinal scotopic sensitivity was also measured. Results: Eight patients demonstrated change in the shape and size of the PED following gas injection. Four patients showed a better delineation of underlying structures on FA. Three patients had focal laser treatment to the newly visible choroidal neovascular complex, but this was successful in only one patient with flattening of the PED. Conclusion: Pigment epithelial detachments can be modified by intravitreal gas injection in some patients, but this treatment did not have a major impact on overall outcome or management.     

吗啡的呼吸抑制作用与中枢胆碱能系统的关系

本文以兔呼吸频率、通气量和血气作为指标,观察到iv吗啡0.5～4.0mg/kg产生剂量依赖性呼吸抑制。icv匹鲁卡品2.5mg/kg能完全逆转这一抑制效应。icv 4—氨基吡啶(4—AP),1.5μg/kg兴奋呼吸,并使吗啡量效曲线右移。用利血平耗竭儿茶酚胺后,吗啡仍能抑制呼吸,4—AP可消除之。表明吗啡抑制呼吸与中枢胆碱能系统有关,且可能系它抑制Ach释放所致。     

扩散管配制甲醛标准气体的研究

介绍了扩散法配制标准气体的方法。以三聚甲醛为原料，通过加热催化分解三聚甲醛蒸气，来配制甲醛标准气体。讨论了配制甲醛标准气体的准确性、稳定性、重复使用性，以及温度、扩散管几何尺寸、载气气流、配气源物质的量等因素对三聚甲醛扩散率的影响。本方法制备的甲醛标准气体，扩散率（２～５０μｇ／ｍｉｎ）测定总不确定度小于５％。     

变换型煤用于制造低含量CO水煤气气化的研究

在小型单管气化反应炉内进行了本题的研究。用粉煤和变换剂制成的型煤进行了水煤气气化反应试验，考察了变换剂种类添加量，气化反应温度，反应时间，蒸汽流量对煤气组成的产气率的影响。结果表明，Ｃａ基变换剂可使煤气ＣＯ含量ψ降低０．１０左右，Ｃａ－Ｎａ复合变换剂还可显著提高煤气产率。