利用压力-容积曲线选择呼气末正压治疗急性呼吸窘迫综合征

目的探讨利用压力-容积曲线选择呼气末正压(PEEP)对急性呼吸窘迫综合征(ARDS)患者肺力学、血流动力学及动脉血气参数的影响,并选择最佳PEEP范围.方法选择16例确诊为ARDS患者,根据压力-容积曲线,设下拐点压力为PLIP,设上拐点压力为PUIP.分别选择PEEP为0、PLIP/2、PLIP、(PLIP+PUIP)/2和PUIP,测量肺力学、血流动力学及动脉血气参数的变化.结果当PEEP为PLIP/2时,动脉血氧分压与吸入氧浓度比(PaO2/FiO2)及Cst虽然较未加用PEEP时有改善(P<0.05及P<0.01),但尚未达到正常水平;当PEEP为PLIP时,PaO2/FiO2及Cst较PLIP/2时有显著提高(P<0.01),接近正常范围;当PEEP为PUIP时,PaO2/FiO2较(PLIP+PUIP)/2时显著增高(P<0.01),但Cst较PLIP时反而有所降低(P<0.01),MAP下降(P<0.01),CVP升高(P<0.01),同时Pip增高(P<0.01).结论ARDS患者行呼吸机治疗时,在PLIP～PUIP之间可有效纠正低氧血症,而对血流动力学影响较小,可获得满意疗效.     

BiPAP呼吸机正压给氧对增强肺癌放疗疗效的随机对照试验

目的　观察BiPAP呼吸机正压给氧对放射治疗 (简称放疗 )的影响 ,以探索提高中晚期肺癌治疗的新途径。方法　确诊的肺癌患者 30例随机分为联合治疗组和单纯放疗对照组 ,前者采用BiPAP呼吸机经鼻面罩正压通气给氧联合常规放疗 ,后者采用常规放疗 (6MV X)。观察通气前、后血氧分压 (PaO2 )、血氧饱和度 (SaO2 )变化和放疗前、后胸部X线片、血常规、细胞免疫功能变化 ,以及毒副反应发生情况。结果　①BiPAP呼吸机经鼻面罩正压通气给氧可明显提高PaO2 ,最高可增加 7.5kPa ,同时SaO2 均维持在 95 %以上。肺癌治疗有效率较对照组增加 6 .7个百分点。②治疗组放疗前后细胞免疫功能无明显变化 (P >0 .0 5 ) ,而对照组在放疗后淋巴细胞转化率、CD4及CD4/CD8比值明显降低 (P <0 .0 1 )。③治疗组仅 1例出现白细胞减少 (6 .7% ) ,而对照组有 5例出现白细胞明显降低 (33.3% ) ,需用升白药物才能继续完成放疗。胃肠道反应发生较对照组明显减少。结论　BiPAP呼吸机经鼻面罩正压通气给氧辅助肺癌放疗有一定疗效 ,可明显提高机体氧分压 ,对骨髓及细胞免疫功能有一定保护作用 ,亦能减少放疗所引起的毒副作用     

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。     

咯血并呼吸衰竭患者机械通气治疗初步观察

目的探索咯血并呼吸衰竭(COPD)患者机械通气治疗的效果。方法阐明了一例表皮葡萄球菌肺部感染的COPD患者产生大咯血并呼吸衰竭的原因及治疗经过,详细分析了治疗过程中的各种临床问题。结果表皮葡萄球菌肺部感染的COPD患者可以有大咯血的临床表现,该患者经抗感染、纤支镜止血、机械通气等积极治疗后得到康复出院。结论机械通气是治疗咯血并呼吸衰竭COPD患者的主要方法之一,咯血并不影响机械通气的治疗效果,机械通气对咯血的治疗也没有造成不良影响。     

胸段硬膜外麻醉对单肺通气肺内分流的影响

目的：研究胸段硬膜外麻醉对单肺通气（ＯＬＶ）时肺内分流（Ｑｓ／Ｑｔ）的影响。方法：选择２８例择期开胸手术病人,分为安氟醚静吸复合全麻加胸段硬膜外麻（ＴＥＡ;Ｔ４～５或Ｔ５～６,１．４％利多卡因）ＯＬＶ组（实验组）和安氟醚静吸复合全麻ＯＬＶ组（对照组）,各１４例。分别于麻醉前、双肺通气１５ｍｉｎ、ＯＬＶ５,１５,３０,６０ｍｉｎ分别抽动脉血和混合静脉血行血气分析,计算Ｑｓ／Ｑｔ。结果：实验组和对照组     

氟碳部分液体通气对吸入性损伤犬的呼吸道组织病理学影响

目的：观察氟碳部分液体通气在治疗吸入性损伤中,呼吸道组织病理的变化,探讨氟碳部分液体通气治疗吸入性损伤的机理。方法：采用蒸汽吸入造成急性呼吸道损伤,观察氟碳部分液通气＋高频通气治疗组与单纯高频通气对照组的气管,支气管,肺的光镜下HE染色的组织形态变化。结果：（1）对照组和治疗组均表现为左侧支气管,肺病变轻于右侧;（2）治疗组病变轻于对照组。结论：吸入性损伤的组织病理学改变以右侧为重,氟碳部分液体通气,可减轻吸入性损伤呼吸道充血水肿,并有明显的抗炎作用,可能为其治疗吸知识性损伤的机理之一。     

Transcranial Doppler sonography in craniosynostosis

In the management of craniosynostosis, there is a need for quantitative assessment of treatment methods and outcome. Radiology and pressure studies are well documented, but so far little attention has been given to cerebral blood flow changes and their possible relevance. This paper reports our initial experience using transcranial Doppler sonography to calculate the cerebrovascular resistance and cerebral blood velocities in the major basal vessels before and after surgery for craniosynostosis. Ten patients were studied using the Scimed 2-MHz probe through the temporal and frontal windows of the skull. Measurements were taken under standard physiological conditions before, during and after surgery. Preliminary results suggest that this non-invasive technique may be helpful in predicting and assessing the outcome following surgery for craniosynostosis.     

P0.1 is a useful parameter in setting the level of pressure support ventilation

Objective The purpose of this study was to investigate whether changes in breathing pattern, neuromuscular drive (P0.1), and the work involved in breathing might help to set the individual appropriate level of pressure support ventilation (PSV) in patients with acute respiratory failure (ARF) requiring ventilatory assistance.Design: A prospective, interventional study.Setting An 8-bed multidisciplinary intensive care unit (ICU).Patients Ten patients with ARF due to adult respiratory distress syndrome (ARDS), sepsis or airway infection were included in the study. Chronic obstructive pulmonary disease (COPD) patients with acute exacerbation were excluded. None of these patients was in the weaning process.Interventions We found a level of pressure support able to generate a condition of near-relaxation in each patient, as evidenced by work of breathing (WOB) values close to 0 J/l. This level was called PS 100 and baseline physiological measurements, namely, breathing pattern, P 0.1 and WOB were obtained. Pressure support was then reduced to 85%, 70% and 50% of the initial value and the same set of measurements was obtained.Measurements and results Flow ( ) was measured by a flow sensor (Varflex) positioned between the Y-piece of the breathing circuit and the endotracheal tube. Tidal volume was obtained by numerical integration of the flow signal. Airway pressure (P_aw) was sampled through a catheter attached to the flow sensor. Esophageal pressure (P_es) was measured with a nasogastric tube incorporating an esophageal balloon. The esophageal balloon and flow and pressure sensors were connected to a portable monitor (CP 100 Bicore) that provided realtime display of flow, volume, P_aw and P_es tracings and loops of P_es/V, P_aw/V and /V relationships. The breathing pattern was analyzed from the flow signal. Patient work of breathing (WOB) was calculated by integration of the area of the P_es/V loop. Respiratory drive (P 0.1) was measured at the esophageal pressure change during the first 100 ms of a breath, by the quasiocclusion technique. When pressure support was reduced, we found that the respiration rate significantly increased from PS 100 to PS85, but varied negligibly with lower pressure support levels. Tidal volume behaved in a similar way, decreasing significantly from PS 100 to PS85, but hardly changing at PS 70 and PS 50. In contrast, WOB and P 0.1 increased progressively with decreasing pressure support levels. The changes in WOB were significant at each stage in the trial, whereas P 0.1 increased significantly from PS 100 at other stages. Linear regression analysis revealed a highly positive, significant correlation between WOB and P 0.1 at decreasing PSV levels (r=0.87), whereas the correlation between WOB and ventilatory frequency was less significant (r=0.53). No other correlation was found.Conclusions During pressure support ventilation, P 0.1 may be a more sensitive parameter than the assessment of breathing pattern in setting the optimal level of pressure support in individual patients. Although P 0.1 was measured with an esophageal balloon in the present study, non-invasive techniques can also be used.     

Respiratory effects of tracheal gas insufflation in spontaneously breathing COPD patients

Objective To evaluate the effect of tracheal gas insufflation (TGI) in spontaneously breathing, intubated patients with chronic obstructive pulmonary disease (COPD) undergoing weaning from the mechanical ventilation.Design A prospective study in humans.Setting Polyvalent intensive care unit (14-bed ICU) in a 700-bed general university hospital.Patients Twelve patients with chronic obstructive pulmonary disease (COPD) who required intubation and mechanical ventilation were studied. All patients met standard criteria for weaning from mechanical ventilation. Seven patients (group 1) had been transorally intubated during episodes of acute respiratory failure. Five patients, all men (group 2), had previously undergone tracheostomy and had a transtracheal tube in place.Interventions Intratracheal, humidified, O₂-mixture insufflation (TGI) was given via a catheter placed in distal or proximal position. Gas delivered through the intratracheal catheter was blended to match the fractional of inspired gas through the endotracheal tube. Continuous flows of 3 and 6 l/min in randomized order were used in each catheter position. Prior to data collection at each stage, an equilibration period of at least 30 min was observed, and thereafter blood gases were analyzed every 5 min. A new steady state was assumed to have been established when values of bothP _aCO₂ and CO₂ changed by less than 5% between adjacent measurements. The last values of blood gases were taken as representative. The new steady state was confirmed within 35–50 min. Baseline measurements with zero were made at the beginning and end of the experiment.Results This study shows that V_T, MV,P _aCO₂, and V_D/V_T are reduced in a flow-dependent manner when gas is delivered through an oral-tracheal tube (group 1). The distal catheter position was more effective than the proximal one. In contrast, when gas was delivered through tracheostomy (group 2), TGI was ineffective in the proximal position and less effective than in group 1 in distal position.Conclusion Under the experimental conditions, tracheal gas insufflation decreased dead space, increased alveolar ventilation and possibly reduced work of breathing. From the preliminary data reported here, we believe that TGI may help patients experiencing difficulty during weaning.     

小型液体通气仪的研制及应用

介绍一种自行设计制造的、用于小动物的小型液体通气仪（MLVR）。该MLVR采用单片机控制,呼吸频率、潮气量、吸气时间、呼气时间可以根据需要进行调节。将MLVR应用于大鼠进行液体通气后取得良好效果。