机械通气致下呼吸道黄杆菌感染的临床分析

目的:探讨黄杆菌属致下呼吸道感染的临床特点及对常用抗生素的耐药情况。方法:分析我院六年来机械通气致下呼吸道黄杆菌感染的11例临床资料,平板稀释法测定常用抗菌药物对该菌株的最低抑菌浓度,采用法国生物梅里埃公司API系统进行细菌学鉴定,以美国国家实验室标准化委员会NCCLS的标准判定结果。结果:全部应用广谱抗生素,年龄>60岁者8例,机械通气到发生黄杆菌感染的平均时间为18天,死亡4例;耐药率高,仅对头孢哌酮/舒巴坦、复方磺胺甲恶唑、哌拉西林、左氧氟沙星等较敏感。结论:机械通气致下呼吸道黄杆菌感染常发生在基础状态较差,机械通气时间较长,且长期应用广谱抗生素的老年患者,临床表现常无特征性,细菌耐药严重,病死率高     

BiPAP ViSION 在慢性阻塞性肺疾病Ⅱ型呼吸衰竭的应用和护理

目的 探讨经鼻(面)罩双水平气道内正压通气(BiPAP)ViSION型呼吸机对慢性阻塞性肺疾病(COPD)伴Ⅱ型呼吸衰竭患者疗效及护理特点。方法 应用BiPAP ViSION型呼吸机对21例COPD伴Ⅱ型呼吸衰竭患者采用鼻/面罩连接单向呼气活瓣行双水平气道正压通气,观察其通气前后动脉血气及临床表现变化。结果 通气治疗后19例患者动脉血氧分压(PaO_2)及氧饱和度(SaO_2)明显升高(P<0.01),二氧化碳分压(PaCO_2)显著降低(P<0.05);肺性脑病症状消失,昏迷患者神志转清。2例病情恶化,其中1例改用有创通气后好转,1例拒绝有创通气死亡。结论BiPAP ViSION呼吸机治疗COPD伴Ⅱ型呼吸衰竭的疗效较为肯定,正确的护理对提高其疗效和减少并发症至关重要。     

两种剂量氟碳部分液体通气治疗犬吸入伤的比较研究

目的：对比研究两种剂量氟碳（PFC）部分液体通气（PLV）对蒸气吸入性损伤犬的血气和血流动力学的影响，方法：将健康犬15条随机分面两组，即PFC6ml/kg组（PFC－6）和PFC 12ml/kg(PFC-12)组，采用蒸气吸入造成吸入性损伤模型后经气管内注入PFC实施部分液体通气（PLV）治疗，观察治疗后30min,60min,90min血气，血流动力学参数的变化，结果：PFC－6组PaO2在PLV治疗30min后明显升高（P＜0．05），在治疗60min,90min生的PaO2与致伤值比较无统计学意义，而PFC－12组的PaO2在PLV治疗后30min,60min,90min均明显升高（P＜0．05），与PFC－6组相比，PFC－12组的PaO2,PvO2均呈上升趋势，但未达显著水平（P＞0．05），在PLV治疗后各时间点的PaCO2HR,MAP,CVP 致伤值相比均无明显变化（P＞0．05），两组之间比较，各对应时间点的PaCO2,HR,MAP,CVP也均无明显变化（P＞0．05），结论：氟碳部分液体通气是一种新的通气技术，它能明显改善蒸气入伤犬的氧合作用，对血液动力学参数无不良影响，两种剂量氟碳部分液体通气治疗蒸气吸入性损伤未呈现明显剂量一效应关系。     

无创正压通气不同压力支持水平对正常人呼吸做功的影响

目的 :观察无创正压通气 (NIPPV)不同压力水平对正常人呼吸做功的影响 ,为临床合理地应用NIPPV提供理论依据。方法 :选择 9例正常人行NIPPV并寻找出“最舒适”的吸气压力水平 (IPAP) ,在此压力基础上增加或减少 2 5 %的压力 ,构成低IPAP、最舒适IPAP和高IPAP三个压力水平 ,每一IPAP水平通气 15min以上 ,比较不同压力水平呼吸做功改变。结果 :受试者认为“最舒适”的IPAP为 (11.33± 3.2 0 )cmH2 O ,EPAP为 (4 .5 6± 0 .88)cmH2 O[相当于PSV水平为 (6 .77± 3.2 0 )cmH2 O]。与自主呼吸相比 ,NIPPV增加VE的同时 ,总的呼吸做功(Wtot)明显增加 (P <0 .0 5 ) ,而受试者吸气肌做功占总的吸气做功的百分比 (Wi,p/Wi)明显减少 (P <0 .0 5 )。在最舒适IPAP时 ,Wi,p/Wi降低到基础值的 14 %± 9%。这种变化趋势与IPAP的水平相关。结论 :NIPPV可以显著降低吸气肌肉做功。吸气肌做功减少的比例与IPAP的水平相关。研究的结果为NIPPV时PSV的参数设定提供了生理学的依据。     

Evaluation of an Australian intervention to encourage breast feeding in primiparous women

Breast feeding has nutritional, immunologic and antiallergicadvantages for the infant. Although it has been widely recommendedthat infants be exclusively breast fed until 4–6 monthsof age, only about half of all Australian babies currently receiveextended breast feeding. The present study evaluated an intensiveprogramme designed to increase the proportion ofprimi-parousmothers who breast fed for 4 months or longer. Women who registeredwith the hospital at least 20 weeks before delivery and whointended to breastfeed were eligible for the study. Two hundredand thirty-five women were allocated to receive either usualcare or an intensive breast feeding programme when they registeredwith the hospital. The intensive programme consisted of writtenmaterials, and group and individual sessions with a lactationcounsellor. It also included a visit from a breastfeeding consultantwhile in hospital after the birth and contact on return home.Women were followed up 6 weeks and 4 months after delivery.There were no significant differences in breastfeeding ratesbetween the control and intervention groups at either follow-uppoint. Breast feeding until 4 months was more likely among womenwhose baby did not receive a bottle feed while still in hospitaland who did not smoke, use the combined oral contraceptive pillor introduce solid food before 4 months. Those mothers who enjoyedand felt satisfied with breastfeeding were more likely to continueto 4 months. It seems likely that programmes designed to increasebreastfeeding will need to address underlying factors such ashospital policy rather than simply providing more health education.     

The effects of inverse ratio ventilation on intracranial pressure: a preliminary report

Objective: To determine the effects of pressure control inverse ratio ventilation [PC-IRV], as compared with volume controlled normal ratio ventilation [VC], on the intracranial pressure [ICP] of patients with severe head injury. Design: A prospective study with unblinded intervention. Setting: The Intensive Therapy Unit of a base hospital. Patients and participants: Nine cases of head injury requiring mechanical ventilation and intracranial pressure monitoring were studied. Interventions: Patients were twice transferred from VC (I:E ratio 1:2) to PC-IRV (I:E ratio 2:1). Firstly, tidal volume was maintained at an equal value. Secondly, end tidal CO₂ was maintained at an equal value. No other changes were made to ventilation, vasopressor therapy or ICP control. Measurements and results: Measurements were taken of ICP, mean arterial pressure (MAP) end tidal CO₂ and respiratory parameters. In the first observation, there were significant changes in peak inspiratory pressure (PIP), mean airway pressure (Paw) and intrinsic positive end expiratory pressure (PEEP) but not for ICP, end tidal CO₂, MAP and cerebral perfusion pressure (CPP). The correlation between change in ICP and change in end tidal CO₂ was r=–0.74. In the second observation there were significant changes in tidal volume, PIP, Paw and intrinsic PEEP but not for ICP, MAP and CPP. The correlation between the change in ICP and the change in Paw was insignificant. Conclusions: PC-IRV has a minimal net effect on ICP. Changes in ICP correlate more strongly with changes in CO₂ than changes in Paw. Received: 16 January 1996 Accepted: 2 September 1996     

Nitric oxide administration after the ventilator: evaluation of mixing conditions

Background: Because of the potential toxicity of nitric oxide (NO) and its oxidising product nitrogen dioxide (NO₂), any system for the delivery of inhaled NO must aim at stable and predictable levels of NO and as low concentrations as possible of NO₂.
Methods: In a laboratory set-up, we have evaluated mixing conditions in a system where NO is added after the ventilator with continuous flow. Mixing was studied by using carbon dioxide (CO₂) as a tracer gas since capnography has a short response time (360 ms) in comparison with measurements of NO with electrochemical fuel cells (response time of 18s). CO₂ (in volumes corresponding to an ideal mixture of 1,3 and 6%) was fed, after the ventilator, either into plain breathing tubing, into one or two soda lime absorbers, or into an empty and a soda lime-filled canister, at different ventilatory rates and different I: E ratios. Samples were drawn from the inspiratory limb close to the Y-piece. NO was added in the same way and in the same volume as the highest concentration of CO₂.
Results: CO₂ added to plain tubing resulted in peak levels up to five times the set levels, while addition to a mixing box with an empty and a soda lime-filled canister resulted in even mixing with gas concentrations close to the ideal. When NO was fed into plain tubing, low levels were measured at the Y-piece, indicating poor mixing. Gas supply to a mixing chamber resulted in even concentrations.
Conclusions: Even and predictable levels of NO can be obtained with continuous flow of NO to the inspiratory limb, after the ventilator, if a mixing chamber is used. To obtain adequate mixing, the volume of the mixing box should be greater than the tidal volume.     

Decreased incidence of headache after accidental dural puncture in caesarean delivery patients receiving continuous postoperative intrathecal analgesia

To examine the effects of prolonged (> 24 h) intrathecal catheterization with the use of postoperative analgesia on the incidence of post–dural puncture headache (PDPH), charts of 45 obstetric patients who had accidental dural puncture following attempts at epidural block were reviewed retrospectively. Three groups were identified: Group I (n = 15) patients had a dural puncture on the first attempt at epidural block, but successful epidural block on a repeated attempt; Group II (n=17) patients had a dural puncture with immediate conversion to continuous spinal anaesthesia with catheterization lasting only for the duration of caesarean delivery; Group III (n= 13) patients had an immediate conversion to spinal anaesthesia and received post–caesarean section continuous intrathecal patient–controlled analgesia consisting of fentanyl 5 (ig'ml^-1 with bupivacaine 0.25 mg·ml^-1 and epinephrine 2 μg·ml^-1 with catheterization lasting >24 h. No parturient in group III developed a PDPH. This was substantially lower ( P < 0.009) than the 33% incidence for group I and the 47% incidence for group II. The incidence of a PDPH did not differ between group I and II. Similarly, there was no difference between group I and II with regard to requests for a blood patch. Patients receiving continuous intrathecal analgesia had excellent pain relief, could easily ambulate and none complained of pruritus, nausea, vomiting, sensory loss or weakness. In conclusion, indwelling spinal catheterization > 24 h with continuous intrathecal analgesia following accidental dural puncture in parturients may for some patients be a suitable method for providing PDPH prophylaxis and postoperative analgesia.     

An Electrically Modulated Drug Delivery Device. III. Factors Affecting Drug Stability During Electrophoresis

A number of factors affecting the stability of propranolol HC1 during electrophoretic control were investigated. It was found that significant degradation of propranolol HC1 and hydrolysis of water occurred when a current of 15 mA was used with platinized electrodes. This degradation was thought to be due to decomposition of propranolol HC1 at the electrodes. Degradation could be significantly reduced by using uncoated platinum electrodes and currents in the range of 0 to 2.5 mA, while still allowing control of drug delivery rates. Electrode reaction processes were found at high ionic strengths and high drug concentrations but were not thought to be associated with drug decomposition.