影响脑梗死后行机械通气患者撤机的危险因素分析

目的探讨影响脑梗死机械通气患者撤机的危险因素。方法需要机械通气的急性脑梗死患者38例,前瞻性观察机械通气前及撤机前的格拉斯哥昏迷量表（GCS）评分、生命体征、血液生化指标、浅快呼吸指数（RSBI）和血气分析等指标及其动态变化（用两者差值表示）。根据撤机后48h是否需要重新应用呼吸机分为失败组（9例）和成功组（29例）。结果①38例患者中29例成功撤机,9例失败,撤机失败组平均年龄高于成功组,肺部感染和消化道出血的比例亦高于成功组,差异均具有统计学意义,P〈0．01。②呼吸相关指标比较中,呼吸频率、RSBI和氧合指数等指标在成功组和失败组之间以及每组通气前和撤机前的比较中,差异均具有统计学意义,P〈0．05。两组撤机前与通气前的差值比较中,PaCO2、氧合指数和RSBI的差值比较具有统计学意义。③血常规和生化相关指标比较中,GCS评分、ALT等指标在成功组和失败组之间以及每组通气前和撤机前的比较中,差异均具有统计学意义,P〈0．05。两组撤机前与通气前的差值比较中GCS、体温、血小板等的差值比较具有统计学意义。④多因素分析结果表明,与撤机相关的独立因素为机械通气前后RSBI和GCS的差值,两者联合预测撤机成功的敏感性为93．1％,特异性为66．7％,准确性为86．8％。结论动态监测脑梗死机械通气患者的意识状态和浅快呼吸指数有助于对撤机时机的把握。     

Closed loop stimulation and accelerometer-based rate adaptation: results of the PROVIDE study

Aims: We compared pacing rate adaptation based on closed loop stimulation(CLS) or accelerometer sensor (AS) during acute mental and physicalstress in the same patient. Methods and results: One month after Protos (Biotronik, Germany) pacemaker implantation,131 chronotropically incompetent patients were randomized toAS or CLS for 3 months with crossover. Arithmetic and 6 minwalk tests were performed in the non-rate-adaptive mode andAS and CLS rate-adaptive modes, respectively. At the end, patientshad to select the individually preferred pacemaker sensor. Heartrate during mental stress was higher (3.0 ± 9.2 bpm)in the CLS than in the AS mode (P = 0.004). Benefit in the walkingdistance compared with non-rate-adaptive pacing was similarfor the two modes: added 27 ± 96 m (AS, P = 0.013) and30 ± 116 m (CLS, P = 0.025). At the end of the walk,heart rate was higher by 4.8 ± 21.4 bpm in AS than inCLS (P = 0.049). Twice as many patients preferred CLS over AS(P < 0.01). Conclusion: The arithmetic test was associated with a significantly higherheart rate for CLS than for AS, showing a greater sensitivityof CLS-based rate adaptation to mental stress. Performance duringphysical stress was comparable. Patients preferred CLS.     

长期机械通气的老年患者撤机的影响因素分析

目的 筛选老年患者长期机械通气(PMV)的影响因素。方法 收集154例肺部感染或慢性阻塞性肺疾病(COPD)急性加重患者，在机械通气(简称通气)前及撤机或通气21d时的各项指标。结果 单因素分析结果表明：年龄、是否卧床、白细胞数、中性粒细胞比例、肺泡动脉血氧分压差[P（A-a）O2]、尿素氮、肌酐、上消化道出血、心率、血压，短期通气组撤机时或PMV组通气21d时上述指标及心功能、意识状态为PMV的影响因素。多因素分析结果表明：与PMV相关的独立因素为年龄、通气21d时P（A-a）O2及心功能；年龄≥82．0岁、通气21d时P（A-a）O2≥95．0mmHg、心功能≥3级为PMV的危险因素。随后检验8例PMV患者，同时满足3项指标判定PMV的准确性为87．5％。结论 年龄、通气21d时P（A-a）O2及心功能为影响PMV的独立因素。     

Biofeedback and progressive relaxation in weaning the anxious patient from the ventilator: a brief report

Weaning patients with chronic obstructive pulmonary disease from mechanical ventilators is occasionally a long and difficult process complicated by the patient's fear of losing his or her breath during the weaning procedure. A case is presented of an anxious 58-year-old man who was taught to relax using biofeedback and progressive relaxation during aerosol "T-piece" weaning trials. The relaxation effect was elicited by having the patient contract and relax specific muscle groups in a progressive manner, to experience the difference between the states. Ear oximetry served as physiologic feedback as well as a safety feature in the event of oxygen desaturation during exercise. During and after the exercises he felt secure breathing without the ventilator as measured by the physiologic parameters: heart rate, respiratory rate, and oxygen saturation determined by oximetry.     

闭环式频率适应性起搏器对情绪刺激的反应

目的 比较情绪反应在起搏器程控为闭环刺激(CLS)和加速度计(DDDR)方式时心房起搏频率的变化.方法 共54例患者植入具有CLS和加速度计两种频率适应性算法的起搏器,比较分别将起搏器程控为CLS和DDDR方式时,患者情绪反应对心房起搏频率的影响.结果 随访3个月,有35例患者符合情绪反应测试要求,进行情绪反应测试.与将起搏器程控为DDDR方式比较,将起搏器程控为CLS方式时情绪反应引起的心房起搏频率相关性更好,平均心房起搏频率(70.57±4.80)次/min vs(61.72±3.68)次/min,(P<0.001).结论 闭环式频率适应性起搏器比体动方式频率适应性起搏器在情绪反应方面具有更好的心房起搏频率调节作用.     

闭环刺激双腔频率适应性起搏器的临床应用

目的介绍感知体动和精神活动的闭环刺激双腔频率适应性起搏器的初步应用经验.方法植入第3d开启闭环刺激频率适应功能,患者进行坐卧位、散步、快走、上下楼、思考等活动,第7d动态心电图检查和起搏器程控.3个月后随访,重复上述活动和检查,对比分析结果.结果18例患者植入闭环刺激双腔频率适应性起搏器(Biotronik公司的Inos2CLSDDDR),心室起搏阈值0.3～0.7(0.4±0.3)V,R波振幅9.5～21.8(14.6±7.5)mV,阻抗520～870(610±78)Ω;心房起搏阈值0.3～0.8(0.5±0.3)V,A波振幅7.2～16.4(11.6±5.7)mV,阻抗510～872(697±92)mV.随访50～486(236±107)d,均为频率适应性双腔起搏,体力和脑力活动时起搏频率能按需增加.与植入时相比,频率适应功能增强且更加个体化.结论Inos2CLS除适应体动变化外,还能适应精神负荷变化,自动完成初始参数和昼夜频率调整,程控简单,随访方便.     

Antiarrhythmic benefits of dual chamber stimulation with rate-response in patients with paroxysmal atrial fibrillation and chronotropic incompetence: a prospective, multicentre study.

BACKGROUND: While the haemodynamic benefits of DDDR pacing compared with DDD pacing in patients with brady-tachy syndrome and chronotropic incompetence (CI) are well demonstrated, the antiarrhythmic advantage is controversial and so far not clearly demonstrated. AIM: We have performed a prospective, randomized, multicentre study to evaluate the efficacy of DDDR and DDD pacing modes in preventing paroxysmal atrial fibrillation (PAF) episodes in patients with brady-tachy syndrome and CI. METHODS AND RESULTS: Seventy-eight patients were included in the study. All patients had a dual chamber pacemaker implanted and were randomly programmed to DDD or DDDR with a cross over (DDD --> DDDR or vice versa) at 3 months. The final evaluation was performed at 6 months by means of two self-administered symptom questionnaires to evaluate activity. Symptoms of palpitations were analysed and scored. The patients were less symptomatic with the DDDR mode. The number of mode-switch activations compared with symptomatic episodes of PAF confirmed the high rate of asymptomatic PAF episodes in patients with brady-tachy syndrome. We conclude that in a small but well defined population of patients affected by sick sinus syndrome with CI and severely symptomatic PAF, DDDR pacing compared with DDD pacing may offer an additional antiarrhythmic benefit and should be considered the primary mode of pacing.     

Factors influencing weaning from mechanical ventilation in elderly patients with severe pneumonia

Aims: The purpose of this study was to determine the factors that adversely affect the weaning of elderly patients with community‐acquired pneumonia from mechanical ventilation. Methods: This study retrospectively investigated the medical records of 71 elderly patients (65 years or older) who were admitted to the hospital because of community‐acquired pneumonia and required mechanical ventilation between January 2003 and December 2007. The patients were divided into two groups: group A, which included 33 patients who were successfully weaned from mechanical ventilation, and group B, which included 38 patients who could not be weaned from mechanical ventilation. The study compared the patients' background, vital signs, and laboratory and bacteriological examinations at the beginning of mechanical ventilation. A multiple logistic regression analysis was performed to identify the factors associated with difficulties in weaning patients from mechanical ventilation. Results: In group B, there were significantly more smokers (P < 0.05) and more patients with emphysematous changes on thoracic CT (P < 0.05). In group A, the concentrations of total serum protein (P < 0.05) and albumin (P < 0.05) were significantly higher. A multiple logistic regression analysis revealed that patients with community‐acquired pneumonia who showed emphysematous changes on thoracic CT (OR = 4.92, 95%CI 1.08–22.46) and/or a low concentration of serum albumin <3.0 g/dL (OR = 4.25, 95%CI 1.17–15.45) had difficulty being weaned from mechanical ventilation. Conclusion: Our study suggests that elderly patients with community‐acquired pneumonia with emphysematous changes on thoracic CT and/or a low concentration of serum albumin level have difficulty being weaned from mechanical ventilation. Geriatr Gerontol Int 2012; 12: 277–283.     

程序化撤机在脑梗死患者机械通气中的应用价值

目的评价程序化撤机策略在重症脑梗死患者机械通气(MV)中的应用价值。方法分别采用程序化撤机(程序组,34例)和经验性撤机(经验组,35例)2种方法对MV的重症脑梗死患者进行撤机试验,对比2组撤机成功率、MV时间、住院时间以及呼吸机相关性肺炎(VAP)等并发症的发生率和住院费用。结果程序组撤机成功率高于经验组(67.6%vs 42.9%,P<0.05);与经验组比较,程序组撤机前MV时间、总MV时间和住ICU时间均明显缩短,差异有统计学意义(P<0.05)。程序组VAP发生率、气管切开、住院死亡和住院费用方面均明显低于经验组(P<0.05);2组48h内再插管比较差异无统计学意义(P>0.05)。结论程序化撤机策略能提高撤机成功率,缩短MV时间,降低并发症发生率,减少住院费用,为脑梗死患者提供了一种安全且有效的撤机方式。     

Closed loop stimulation in prevention of vasovagal syncope. Inotropy Controlled Pacing in Vasovagal Syncope (INVASY): a multicentre randomized, single blind, controlled study.

OBJECTIVES: To determine whether dual-chamber rate-adaptive Closed Loop Stimulation (CLS) could prevent recurrence of Vasovagal Syncope (VVS). BACKGROUND: During VVS, an increase in myocardial contractility associated with a reduction of ventricular filling produces an increase in baroreceptor afferent flow and a consequent decrease in the heart rate. The CLS algorithm is a form of rate-adaptive pacing, which responds to myocardial contraction dynamics, by measuring variations in right ventricular intracardiac impedance: during an incipient VVS it could increase paced heart rate and avoid bradycardia, arterial hypotension and syncope. METHODS: Fifty patients (27 males, mean age 59+/-18 year) with severe and recurrent vasovagal syncope and positive Head Up Tilt Test (HUTT) with cardioinhibition, received a CLS pacemaker (INOS2, Biotronik GmbH Co., Germany). The primary end point was recurrence of two VVSs during a minimum of 1 year of follow-up. Randomization between DDD-CLS and DDI mode (40 bpm) pacing was performed only during the first stage of the study (first year): 9/26 randomized to DDI mode (control group) and 17/26 in DDD-CLS mode. All the 24 patients recruited in the second stage of the study (second year) were programmed in DDD-CLS mode. RESULTS: Of the nine patients randomized to the DDI mode, seven had recurrences of syncope during the first year. At the end of the first year the nine patients were reprogrammed to the CLS mode and no syncope occurred after reprogramming. The 41 patients programmed to CLS had a mean follow-up of 19+/-4 months: none reported VVS, only four (10%) reported occasional presyncope and their quality of life greatly improved. Positive HUTT at the end of the first year failed to predict the clinical response to CLS pacing. CONCLUSIONS: The study demonstrates the effectiveness of CLS pacing in preventing cardioinhibitory VVS. A possible placebo effect of pacemaker implantation occurred in 22% of patients.     

慢性阻塞性肺疾病呼吸衰竭机械通气脱机策略

目的 探讨COPD呼吸衰竭有创机械通气脱机策略.方法 机械通气治疗COPD呼吸衰竭108例,分析治疗结果.结果 106例患者成功脱机、拔管,抢救成功率达98％.结论 采取恰当有创机械通气脱机策略,有较高抢救成功率.     

Factors associated with failure of weaning from long-term mechanical ventilation after cardiac surgery

The purpose of this prospective, quantitative, comparative study, conducted at the 55 bed cardiothoracic intensive care unit of the Heart Institute (InCor), University of Sao Paulo Medical School, was to identify factors involved in the weaning of patients who require long-term (> 10 days) mechanical ventilation after cardiac surgery. The subjects included all patients who underwent open-heart surgery with cardiopulmonary bypass during a 10 month period from April 2000 to January 2001 (n = 946). From this group, 52 (5.7%) patients who required a tracheotomy for the management of long-term mechanical ventilation after cardiac surgery with cardiopulmonary bypass were selected. Pre-, intra- and postoperative data from patients who were not successfully weaned after reintubation and who underwent an elective tracheotomy were compared. Parameters of respiratory mechanics such as respiratory complications, oxygenation, and cardiac, renal, and neurological function were evaluated. Weaning success was defined as the ability of a patient to tolerate 48 hours without pressure or flow support from a mechanical ventilator. A patient was considered to have failed weaning if they died or remained under ventilation for more than 8 weeks. Of the 52 patients studied, 25 were successfully weaned, 21 died, and 6 remained ventilated for more than 8 weeks. We found significant statistical differences (P < 0.05) between the groups with respect to success or failure in LVEF (P = 0.0035), the need for vasoactive agents (P = 0.0018), and renal failure (P = 0.002). Parameters of respiratory mechanics and oxygenation (eg, static airway compliance, airway resistance) did not influence the success or failure of weaning. There was a significant difference in relation to the presence of pneumonia (P = 0.0086) between the two groups. Although neurological complications were more frequent in patients in the weaning success group, the failure group had lower GCS scores, which is indicative of worse prognoses. It is concluded that cardiac dysfunction, the need for dialysis, and pneumonia are determinants for weaning failure in patients undergoing long-term mechanical ventilation after cardiac surgery.     

慢性阻塞性肺疾病撤机困难呼吸力学特征10例分析

目的为提高慢性阻塞性肺疾病(COPD)患者撤机成功率提供生理学依据。方法检测2006年1月至2009年12月广州医学院第一附属医院收治的10例撤机困难COPD患者的呼吸力学指标,观察患者自主呼吸(SB)及机械通气时的呼吸力学指标变化。结果 SB时的呼吸频率(RR)、潮气量(VT)和分钟通气量(Ve)分别为(27.94±8.23)次/min、(0.266±0.107)L和(6.843±1.333)L/min,机械通气时的RR降低,而VT和Ve时升高(均P<0.05)。SB和机械通气时的动态内源性呼吸末正压分别为(0.82±0.19)kPa和(0.41±1.12)kPa,SB时明显增高(P<0.01),吸气中期气道阻力(RL)(2.43±0.94)kPa/(L.S)。SB时的P0.1为(0.61±0.16)kPa。SB时的最大跨膈压、最大食管负压和最大吸气口腔压分别为(5.08±0.93)kPa、(-5.00±0.95)kPa和(-3.78±0.86)kPa。SB时跨膈压(Pdi)和吸气压力时间乘积(PTPins)分别为(0.82±0.20)kPa和(48.93±11.94)kPa.s;机械通气时较SB显著降低,分别为(0.67±0.17)kPa和(30.33±11.72)kPa.s(P均<0.05)。结论撤机困难COPD患者存在显著的呼吸力学异常,SB时呼吸浅快,动态内源性呼吸末正压、RL与呼吸中枢驱动等均增高,吸气肌肉无力;应用PSV(1.57 kPa)联合PEEP(48%动态内源性呼吸末正压)可降低约50%的动态内源性呼吸末正压、17.8%的Pdi和38%的PTPins。     

Gas exchange alterations associated with weaning from mechanical ventilation following coronary artery bypass grafting

This study was done to clarify the effects of positive-pressure mechanical ventilation on gas exchange in the lungs of conscious patients. Nine hemodynamically stable patients were studied following coronary artery bypass grafting at the time they were weaned from mechanical ventilation. The adequacy of gas exchange was assessed by traditional measurements as well as the multiple inert gas technique used to measure the ventilation-perfusion (VA/Q) distribution. During mechanical ventilation, gas exchange was characterized by a variable degree of VA/Q inequality as well as a substantial shunt ranging from 11.9 to 27.7 percent. Following removal from mechanical ventilation, there was a decrease in the mean VA/Q subsequent to a decrease in the minute ventilation. However, there was no significant change in the level of shunt or in the amount of VA/Q inequality.     

The DDDR closed loop stimulation for the prevention of vasovagal syncope: results from the INVASY prospective feasibility registry.

BACKGROUND: The contraction dynamics of the ventricular myocardium are affected before and during vasovagal fainting suggesting that the Closed Loop Stimulation (CLS) pacemaker could be useful for the treatment of these patients. CLS is a new concept of heart rate modulation in cardiac pacing. The pacemaker INOS(2) CLS (Biotronik, Germany) derives its information for heart rate optimization from myocardial contraction dynamics, by measuring right ventricular intracardiac impedance. The pacemaker becomes an integral part of the circulatory regulation and, therefore, reacts appropriately to different cardiovascular demands. METHODS: In a prospective registry, 34 patients with a history of recurrent vasovagal syncopal events were implanted with INOS(2) DDDR CLS pacemakers. The aim of the study was to evaluate both long term clinical outcome, including the first recurrence of syncope, with DDDR-CLS pacing and acute precipitation of vasovagal fainting with DDDR-CLS mode compared with DDD during head up tilt testing. RESULTS: During a follow up period of 12-50 months, 30 patients experienced no further syncopal events in daily life; 1 patient had no syncope but night palpitations, which were eliminated by pacemaker reprogramming; 2 patients had presyncopal episodes but not syncopes; 3 syncopal recurrences occurred in one patient in chronic atrial fibrillation, possibly not an ideal candidate for implantation. CONCLUSIONS: Further studies for detailed understanding of the preventive mechanism of DDDR-CLS pacing in vasovagal syncope are warranted. A randomized multicentre prospective new study (INotropy controlled pacing in VAsovagal SYncope: INVASY) is now in progress to confirm the beneficial effect of DDDR-CLS pacing in a larger group of patients with recurrent vasovagal syncope.