Lung computed tomography during a lung recruitment maneuver in patients with acute lung injury

OBJECTIVE: To assess the acute effect of a lung recruitment maneuver (LRM) on lung morphology in patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). PATIENTS: Ten patients with ALI/ARDS on mechanical ventilation. DESIGN: Prospective clinical study. SETTING: Computed tomography (CT) scan facility in a teaching hospital. INTERVENTIONS: An LRM performed by stepwise increases in positive end-expiratory pressure (PEEP) of up to 30-40 cm H(2)O. Lung basal CT sections were taken at end-expiration (patients 1 to 5), and at end-expiration and end-inspiration (patients 6 to 10). Arterial blood gases and static compliance (C(st)) were measured before, during and after the LRM. MEASUREMENTS AND MAIN RESULTS: Poorly aerated and non-aerated tissue at PEEP 10 cm H(2)O accounted for 60.0+/-29.1% of lung parenchyma, while only 1.1+/-1.8% was hyperinflated. Increasing PEEP to 20 and 30 cm H(2)O, compared to PEEP 10 cm H(2)O, decreased poorly aerated and non-aerated tissue by 16.2+/-28.0% and 33.4+/-13.8%, respectively ( p<0.05). This was associated with an increase in PaO(2) and a decrease in total static compliance. Inspiration increased alveolar recruitment at all PEEP levels. Hyperinflated tissue increased up to 2.9+/-4.0% with PEEP 30 cm H(2)O, and to a lesser degree with inspiration. No barotrauma or severe hypotension occurred. CONCLUSIONS: Lung recruitment maneuvers improve oxygenation by expanding collapsed alveoli without inducing too much hyperinflation in ALI/ARDS patients. An LRM during the CT scan gives morphologic and functional information that could be useful in setting ventilatory parameters.     

不同呼气末正压水平对肺复张患者脑灌注压及血流动力学的影响

目的 观察肺复张(RM)对颅内压(ICP)、脑灌注压(CPP)及平均动脉压(MAP)的影响.方法 选择因严重颅脑疾患伴肺损伤需要进行机械通气的6例患者,在进行RM的同时进行持续ICP、MAP、中心静脉压(CVP)、脉搏血氧饱和度(SpO2)等监测.RM采用压力控制通气模式,逐步提升呼气末正压(PEEP)的方法.结果 6例患者共进行22例次RM,2例次分别在3 cm H2O(1 cm H2O=0.098 kPa)和6 cm H2O PEEP水平出现MAP、CPP显著降低而终止.其余20例次RM中不同PEEP水平相应的MAP、CVP、ICP、CPP平均值与基础值相比差异均无统计学意义(P均>0.05);MAP与CPP呈高度相关性(r=0.706,P=0.000).20例次RM中,单次RM内参数间呈高度相关性的比例:MAP与CPP占85%(17/20);PEEP与CVP占75%(15/20);PEEP与ICP占75%(15/20);PEEP与CPP占40%(8/20).22例次RM中MAP随PEEP变化有6种趋势:8例次相对稳定;6例次随PEEP增加而降低,然后随PEEP降低而逐渐回升;2例次随PEEP增加而升高,随PEEP降低逐渐回到基础值;2例次随PEEP增加而降低,PEEP降低后MAP不能相应升高;2例次随PEEP增加而增加,在PEEP降到基础值后MAP仍维持在高水平;2例次随PEEP增加MAP急剧降低而终止RM.11例次RM中ICP随PEEP升高而升高,随PEEP降低而降低;6例次在RM过程中无明显变化;3例次RM后ICP处于高值末回到基线.12例次RM中CPP随PEEP升高而降低,随PEEP降低而增加,并随PEEP回到基线时恢复到基础值;6例次无明显变化;2例次CPP维持在低值,分别在PEEP回到基线后10 min、20 min恢复到基础值.结论 RM对MAP、ICP、CPP的影响存在明显的个体差异.ICP监测有助于保障脑部疾患合并肺损伤患者RM实施的安全性.     

Lung recruitment maneuver effects on respiratory mechanics and extravascular lung water index in patients with acute respiratory distress syndrome

BACKGROUND:

Animal experiments showed that recruitment maneuver (RM) and protective ventilation strategy of the lung could improve oxygenation and reduce extravascular lung water. This study was to investigate the effects of RM on respiratory mechanics and extravascular lung water index (EVLWI) in patients with acute respiratory distress syndrome (ARDS).

METHODS:

Thirty patients with ARDS were randomized into a RM group and a non-RM group. In the RM group, after basic mechanical ventilation stabilized for 30 minutes, RM was performed and repeated once every 12 hours for 3 days. In the non-RM group, lung protective strategy was conducted without RM. Oxygenation index (PaO₂/FiO₂), peak inspiratory pressure (PIP), Plateau pressure (Pplat), static pulmonary compliance (Cst) and EVLWI of patients before treatment and at 12, 24, 48, 72 hours after the treatment were measured and compared between the groups. Hemodynamic changes were observed before and after RM. One-way ANOVA, Student''s t test and Fisher''s exact test were used to process the data.

RESULTS:

The levels of PaO₂/FiO₂ and Cst increased after treatment in the two groups, but they were higher in the RM group than in the non-RM group (P<0.05). The PIP and Pplat decreased after treatment in the two groups, but they were lower in the RM group than in the non-RM group (P<0.05). The EVLWI in the two groups showed downward trend after treatment (P<0.05), and the differences were signifcant at all time points (P<0.01); the EVLWI in the RM group was lower than that in the non-RM group at 12, 24, 48 and 72 hours (P<0.05 or P<0.01). Compared with pre-RM, hemodynamics changes during RM were significantly different (P<0.01); compared with pre-RM, the changes were not significantly different at 120 seconds after the end of RM (P>0.05).

CONCLUSIONS:

RM could reduce EVLWI, increase oxygenation and lung compliance. The effect of RM on hemodynamics was transient.KEY WORDS: Lung recruitment maneuver, Acute respiratory distress syndrome, Respiratory mechanics, Extravascular lung water index, Hemodynamics, Lung protective ventilation, Oxygenation index     

高渗盐水复苏对急性脑损伤伴失血性休克患者颅内压脑氧代谢的影响

目的　研究高渗盐水 (HTS)复苏对急性脑损伤伴失血性休克患者颅内压、脑氧代谢的影响。方法　 4 6例急性脑损伤伴失血性休克患者随机分为 3组 :HTS治疗组、甘露醇 (MT)治疗组和平衡液对照组。在平衡液复苏基础上 ,分别在 15min内快速静脉输入 7 5 %HTS 4mL/kg和 2 0 %MT 0 5g/kg。于治疗后 15、30、6 0、12 0min通过侧脑室置管监测颅内压 (ICP) ,计算脑灌注压 (CPP) ;同时分别抽取动脉、颈内静脉球部血行血气分析 ,监测颈静脉血氧饱和度 (SjvO2 )及脑动静脉氧含量差 (Da -jvO2 )。结果　与对照组比较 ,HTS能明显降低ICP ,增加CPP ,改善脑氧供需平衡 (P <0 0 1) ;与MT组比较 ,HTS组降低ICP幅度与其相似(P >0 0 5 ) ,而降ICP作用维持时间较长 ,于治疗后 12 0minICP、CPP值与MT组比较差异有显著意义 (P <0 0 1)。结论　HTS降低ICP效果确切 ,且维持时间较长 ,同时可改善脑氧代谢 ,适于急性脑损伤伴失血性休克患者的急救治疗     

Changes in intracranial pressure and cerebral autoregulation in patients with severe traumatic brain injury

BACKGROUND: Impaired cerebral autoregulation is frequent after severe traumatic head injury. This could result in intracranial pressure fluctuating passively with the mean arterial pressure. OBJECTIVE: This study examines the influence of autoregulation on the amplitude and direction of changes in intracranial pressure in patients with severe head injuries during the management of cerebral perfusion pressure. DESIGN: Prospective study. SETTING: Neurosurgical intensive care unit PATIENTS: A total of 42 patients with severe head injuries. INTERVENTIONS: Continuous recording of cerebral blood flow velocity, intracranial pressure, and mean arterial pressure during the start or change of continuous norepinephrine infusion. MEASUREMENTS AND MAIN RESULTS: Cerebrovascular resistance was calculated from the cerebral perfusion pressure and middle cerebral artery blood flow velocity. The strength of autoregulation index was calculated as the ratio of the percentage of change in cerebrovascular resistance by the percentage of change in cerebral perfusion pressure before and after 121 changes in mean arterial pressure at constant ventilation between day 1 and day 18 after trauma. The strength of autoregulation index varied widely, indicating either preserved or severely perturbed autoregulation during hypotensive or hypertensive challenge in patients with or without intracranial hypertension at the basal state (strength of autoregulation index, 0.51 +/- 0.32 to 0.71 +/- 0.25). The change in intracranial pressure varied linearly with the strength of autoregulation index. There was a clinically significant change in intracranial pressure (> or =5 mm Hg) in the same direction as the change in mean arterial pressure in five tracings of three patients. This was caused by the mean arterial pressure dropping below the identified lower limit of autoregulation in three tracings for two patients. It seemed to be caused by a loss of cerebral autoregulation in the remaining two tracings for one patient. CONCLUSION: Cerebral perfusion pressure-oriented therapy can be a safe way to reduce intracranial pressure, whatever the status of autoregulation, in almost all patients with severe head injuries.     

过度通气对脑血流脑代谢颅内压影响的临床研究

目的　观察过度通气对颅脑手术病人脑血流 (CBF)、脑代谢 (CMR)、颅内压 (ICP)的影响。方法　 2 0例择期行颅脑手术病人 ,行七氟醚麻醉 ,待 1 3MAC时 ,调整呼吸频率 ,使呼气末二氧化碳分压 (PetCO2 )达 30、2 5、2 0mmHg(1kPa =7 5mmHg) ,每阶段稳定 30min。根据颈内静脉球部血、桡动脉血差值计算出CBF、CMRO2 、CMRglu、Clact值的变化。结果　与清醒时通气状态相比 ,在血流动力学维持稳定前提下PetCO2 2 5mmHg时CBF减少 36 %、CMRO2 减少 4 9% ,使CMRglu减少 36 % (P<0 0 5 )。PetCO2 30和 2 0mmHg时CBF比PetCO2 2 5mmHg时增加 2 9% (P <0 0 5 )和减少了 9% (P >0 0 5 )。CMRglu麻醉前与麻醉后相比有显著差异 (P <0 0 5 ) ,但麻醉各时段相比无统计学意义 (P >0 0 5 )。麻醉后不同时段ICP与麻醉前相比有极显著差异 (P <0 0 1) ,PetCO2 2 5和 2 0mmHgICP无明显差异 (P >0 0 5 )。麻醉后颈静脉球部氧饱和度 (SjvO2 )和动脉氧饱和度(PaO2 )与麻醉前相比明显增加 (P <0 0 5 )。麻醉前后SaO2 、pH、Hb、体温 (T)、Clact无明显差异 (P >0 0 5 )。结论　过度换气可降低颅脑手术病人CBF、CMR和ICP ,短时间 (30min)过度换气至PetCO2 2 0mmHg时 ,不仅可以降低ICP ,而且不会引起脑缺氧 ,是过度换气的最低     

Lung recruitment maneuver depresses central hemodynamics in patients following cardiac surgery

Objective To assess the impact of the lung recruitment maneuver on circulation following cardiac surgery.Design and setting Prospective randomized cross-over study at the Departments of Anesthesia and Thoracic Surgery, Copenhagen University Hospital.Patients Ten adult undergoing coronary artery bypass surgery.Interventions Patients were randomized to two durations of lung recruitment maneuvers (40 cmH₂O airway pressure for 10 s and 20 s or vice versa after 5 min) administered immediately after surgery.Measurements and results Transesophageal echocardiography (left ventricular short axis view), pulse contour cardiac output, and arterial blood pressure were monitored continuously. Systemic and pulmonary arterial blood gases were sampled before and after each lung recruitment maneuver to calculate the intrapulmonary shunt. Left ventricular end-diastolic areas decreased significantly during both the 10-s and the 20-s lung recruitment maneuvers. Cardiac output was 5.6±0.8 l/min at baseline, decreasing by 3.0±1.1 l/min and 3.6±1.2 l/min during lung recruitment maneuvers of 10 and 20 s, respectively. Shunt decreased from 20±5% to 15±6% after the first lung recruitment maneuver and from 15±6% to 12±5% after the second.Conclusions Lung recruitment maneuvers markedly reduced cardiac output and left ventricular end-diastolic areas in hemodynamically stable patients following cardiac surgery.This article is discussed by the editorial available at: Supported by the Danish Medical Research Council (no. 22-03-0299 and no. 22-04-0420) and the Danish Heart Foundation (no. 04-10-B152-A230-22194).     

重型颅脑损伤病人体位变化对颅内压及脑灌注压的影响

[目的]分析重型颅脑损伤病人体位变化对颅内压(ICP)和脑灌注压(CPP)的影响.[方法]取12种不同体位,统计比较各种体位变化前后ICP、CPP变化.[结果]仰卧位头部抬高45°、仰卧屈膝位30°及45°可使颅内压明显降低,而左侧卧位头部抬高15°、右侧卧位头部抬高15°后颅内压则明显升高.左侧卧位头部抬高30°脑灌注压明显下降.[结论]不同体位可显著影响重型颅脑损伤病人颅内压和脑灌注压的变化.     

体位对颅脑损伤患者颅内压、脑灌注压的影响

颅内压（ICP）增高是一个复杂的病理生理过程,是重型颅脑损伤的主要并发症。颅内高压如不能及早发现并解除,可引起脑代谢障碍、脑灌注压下降和脑疝形成等严重后果,难以控制的颅内高压病死率达到92％～100％［1-2］。目前脑室内放置 ICP 监测管是临床上常用的方法,被称为ICP 监测的“金标准”［3-4］。颅脑损伤后脑水肿早期,通过实时监测患者的颅内压（ICP）及脑灌注压（CPP）等重要指标,可保证脑组织有足够的血液供应,从而确保脑组织的氧供和糖分需要［5］。研究认为临床护理可影响这些指标的变化,其中患者的体位维持尤为重要［6］。本组选择了复旦大学附属华山医院神经外科急救中心2015年5月至12月期间收治的51例重型颅脑损伤行脑室内 ICP 监测的患者,分别观察其头轴位平卧、头偏位平卧、头轴位床头抬高30°、头偏位床头抬高30°对患者 ICP、CPP 的影响。现报道如下。     

The effects of dihydroergotamine in patients with head injury and raised intracranial pressure

In the first study 6 patients with raised intracranial pressure due to brain oedema following head injury were given dihydroergotamine because of low perfusion pressure. The intracranial pressure fell simultaneously with the increase in arterial pressure. The intracranial pressure fell from 24±2 mmHg by a maximum of 12±1 mmHg after a single intravenous injection of 0.25 mg of dihydroergotamine and remained at a low level for 35–70 min before stabilizing at a new level 5±1 mmHg below the baseline. The initial rapid and marked decrease in intracranial pressure may be the result of a reduced intracranial blood volume, due predominantly to constriction of the more voluminous venous capacitance vessels (by analogy with the corresponding vascular effect of dihydroergotamine on skeletal muscle and skin.) In the second study, experiments using sympathectomized cat skeletal muscle, showed that dihydroergotamine also reduced the hydrostatic capillary pressure, inducing absorption of fluid from the interstitial tissue to blood. It is suggested that a similar transcapillary absorption effect in the damaged brain may be an explanation for the observation that the intracranial pressure stabilized at a level below the initial one following dihydroergotamine.     

急性呼吸窘迫综合征肺复张策略的研究进展

急性呼吸窘迫综合征（acute respiratory distress syndrome，ARDS）的概念是由Ashbaugh等于1967年首次提出的，以非心源性肺水肿、呼吸窘迫和难治性低氧血症为其主要临床特征，当时称之为成人呼吸窘迫综合征（adult respiratory distress syndrome）。后来人们逐渐认识到，ARDS是急性肺损伤（acute lung injury，ALI）的终末阶段，是由各种原因所致急性肺部损伤所引发的呼吸衰竭，于是美国胸科医师学会和欧洲危重病学会分别于1992年5月和10月将成人呼吸窘迫综合征更名为急性呼吸窘迫综合征。     

肺泡复张手法对急性肺损伤氧合的影响

目的　对比研究肺泡复张手法 (RM)分别应用于高频震荡通气 (HFOV)和常规机械通气(CMV)对急性肺损伤 (ALI)氧合的影响。方法　采用肺泡灌洗法建立ALI大耳白兔模型 ,分别行HFOV和CMV通气 ,RM实施压力为 30cmH2 O ,持续 30s。对RM前、期间 (急性肺损伤基础状态 )、RM后 5、 15、30min和 1h时的动脉血气、血压及心率进行监测。结果　应用RM后HFOV组与CMV组的动脉氧分压(PaO2 )显著升高 (P <0 0 1)应用RM后 5minPaO2 升高最为明显 ,分别为 (2 6 3 3± 2 1 4 )mmHg (1mmHg=0 133kPa)和 (2 0 1 9± 5 9 8)mmHg。HFOV组PaO2 始终维持在这一水平 ,而CMV组PaO2 逐渐降低 ,RM后 1h [(12 3 5± 4 7 5 )mmHg]与 5min [(2 0 1 9± 5 9 8)mmHg]差异有显著意义 (P <0 0 5 )。在RM 15min后各时相HFOV组PaO2 显著高于CMV组 (P <0 0 5 )。二氧化碳分压、血压及心率在两组间差异无显著意义。结论　在HFOV和CMV中应用RM均可以有效地复张肺泡 ,改善氧合 ,但RM的复张作用在HFOV较CMV持续更长。     

Non-infectious hyperthermia in acute brain injury patients: relationships to mortality, blood pressure, intracranial pressure and cerebral perfusion pressure

The present study was conducted to investigate the frequency of hyperthermia during the first 72 h after acute brain injury, and to compare subjects that developed hyperthermia with those that did not with respect to blood pressure, intracranial pressure (ICP), cerebral perfusion pressure (CPP), Glasgow Coma Scale (GCS) score and mortality. This study was conducted by performing a retrospective medical record review of 126 brain injury patients admitted to the neurological intensive care unit of a university hospital located in Incheon, South Korea. Our results showed that 25.4% of the subjects had hyperthermia for at least 1 day during the first 3 days of hospitalization. Hyperthermic subjects demonstrated higher mortality and ICP, and lower CPP and GCS scores than non-hyperthermic subjects, indicating a reduced cerebral blood flow. The findings may provide a possible explanation for poor clinical outcome and offer justification for the careful monitoring of body temperature in patients with acute brain injury.     

Prone position in subarachnoid hemorrhage patients with acute respiratory distress syndrome: effects on cerebral tissue oxygenation and intracranial pressure

OBJECTIVE: To analyze the effect of prone position on cerebral perfusion pressure and brain tissue oxygen partial pressure in subarachnoid hemorrhage patients with acute respiratory distress syndrome (ARDS). DESIGN: Clinical study with retrospective data analysis. SETTING: Neurosurgical intensive care unit of a primary level university hospital. PATIENTS: Sixteen patients treated for intracranial aneurysm rupture with initial Hunt and Hess grade III or worse who developed ARDS within 2 wks after the bleeding. INTERVENTIONS: Routine neurosurgical intensive care treatment for subarachnoid hemorrhage and posthemorrhagic vasospasm including cerebral monitoring with continuous intracranial pressure and brain tissue oxygen partial pressure recordings. MEASUREMENTS AND MAIN RESULTS: Hemodynamics, arterial oxygenation, ventilatory setting, intracranial pressure, cerebral perfusion pressure, and brain tissue oxygen partial pressure in the supine as well as in the prone position were analyzed and compared. A significant increase in Pao(2) from 97.3 +/- 20.7 torr (mean +/- sd) in the supine position to 126.6 +/- 31.7 torr in the prone position was joined by a significant increase in brain tissue oxygen partial pressure from 26.8 +/- 10.9 torr to 31.6 +/- 12.2 torr (both p <.0001), whereas intracranial pressure increased from 9.3 +/- 5.2 mm Hg to 14.8 +/- 6.7 mm Hg and cerebral perfusion pressure decreased from 73.0 +/- 10.5 mm Hg to 67.7 +/- 10.7 mm Hg (both p <.0001). CONCLUSIONS: The beneficial effect of prone positioning on cerebral tissue oxygenation by increasing arterial oxygenation appears to outweigh the expected adverse effect of prone positioning on cerebral tissue oxygenation by decreasing cerebral perfusion pressure in ARDS patients.     

肺保护性机械通气对脑损伤患者脑灌注压和脑氧代谢的影响

目的 观察肺保护性机械通气对颅脑损伤患者脑灌注压(CPP)及脑氧代谢的影响.方法 选择ICU需要机械通气的严重颅脑损伤伴呼吸衰竭患者40例,所有患者均行颅内压(ICP)监测、右侧颈内静脉逆行穿刺置管.将患者随机(随机数字法)分为①肺保护性通气组:潮气量为6～8mL/kg,初始吸氧体积分数40％,逐步提升呼气末正压(PEEP),PEEP与吸氧(FiO2)匹配同步升高,保持FiO2允许性低值;②常规通气组(对照组):潮气量为8～ 12 mL/kg,FiO2与PEEP匹配同步升高,保持PEEP允许性低值.监测桡动脉血气、平均动脉压(MAP)、颈静脉血氧饱和度(SjVO2),颈静脉血二氧化碳分压(PjVCO2),计算CPP=MAP-ICP;氧合指数PaO2/FiO2.结果 肺保护性通气组PEEP(8.2 ±3.3) cmH2O(1 cmH2O=0.098 kPa)、ICP (19.7±3.6) mmHg(1 mmHg=0.133 kPa)、PaCO2 (54±7.3 mmHg)高于对照组,VT、FiO2低于对照组,差异具有统计学意义;两组PaO2/FiO2、SjVO2、MAP、CPP差异无统计学意义.相关分析提示PaCO2与CPP呈正相关(r=0.368,P=0.019),与ICP、PaO2、SjVO2、Pjv CO2等并无相关性(P＞0.05);PEEP与ICP呈正相关;PEEP分为≤5 cmH2O、6～ 10 cmH2O及＞10 cmH2O三组,各组间ICP两两比较差异有统计学意义;PEEP在0～ 10 cmH2O上升,CPP变化不明显;PEEP＞ 10cmH2O时与CPP呈明显负相关(r=-0.395,P=0.017),CPP(58.5±7.2) mmHg,低于PEEP 0 ～ 5cmH2O时的(69.1±9.7) mmHg,差异具有统计学意义;PEEP越高,氧合指数越低;不同的PEEP水平下MAP、SjVO2、PjVCO2无明显变化.将PaCO2分为35～45 mmHg和46～60mmHg组,后者的CPP高于前组者,差异具有统计学意义(P＜ 0.05).SjVO2与PaO2及PjvCO2相关,与PaCO2、CPP、ICP、MAP及PEEP等均无相关性.结论 肺保护性通气策略对颅脑损伤患者来说是相对安全的.适当的CO2潴留联合较高的PEEP不影响脑灌注.肺保护性通气与常规通气相比SjVO2差异无统计学意义.提示两种通气方式下脑氧代谢无变化.     

Effect of backrest position on intracranial pressure and cerebral perfusion pressure in individuals with brain injury: a systematic review.

Head elevation is a conventional nursing procedure for brain-injured individuals with intracranial hypertension; it is performed with the intent of reducing intracranial pressure (ICP) by means of a noninvasive physical intervention. However, in certain circumstances, head elevation puts the brain-injured individual at risk for secondary cerebral injury because of impaired arterial blood pressure and compromised cerebral perfusion pressure (CPP). A systematic literature search was conducted to evaluate existing evidence regarding the effect of changing the backrest position on ICP and CPP in brain-injured individuals. Eleven articles were retrieved. In nine articles it was concluded that ICP significantly decreased at 30 degrees of head elevation compared with a flat position. Five of the nine articles showed no statistical significance in the magnitude of change in CPP from a flat position to 30 degrees of head elevation. Major limitations in the 11 articles were small sample sizes and unclear study protocols, which may have caused a failure to detect the effect of head elevation. In clinical practice, intensive care unit staff members need to cautiously perform head elevation with a thorough understanding of its physiologic effect and potential hazard. Future research should investigate the effects of therapeutic positions on different neurological and neurosurgical populations and explore the combination of head elevation and lateral side-lying positions.     

两种肺复张方法治疗急性呼吸窘迫综合征的效果比较

目的 探讨和比较控制性肺膨胀(sustained inflation,SI)和压力控制通气(pressure controlled ventilation,PCV)用于急性呼吸窘迫综合征(ARDS)患者肺复张的效果,及其对血流动力学和呼吸力学方面的影响.方法 对10例ARDS患者采取随机对照实验,在镇静、非肌松状态下,先后采用SI[40cmH2O(1 cmH2O=0.0981 kPa),40 s]和PCV(20 cmH2O,2 min)进行肺复张,中间间隔洗脱期.收集两种方法复张前(T0)、复张后5 min(T2)、1 h(T3)的血气分析、血流动力学指标、呼吸力学指标和复张中(T1)的呼吸力学与血流动力学指标.收集数据行单因素重复测量方差分析.结果 (1)两种方法T2和T3时点PaO2较T0均明显改善(P<0.05),方法间差异无统计学意义(P>0.05).PaCO2在各时点差异均无统计学意义(P>0.05).(2)两种方法T1时点CI均下降(P<0.05),方法间无差异(P>0.05).HR、MAP在各时点差异均无统计学意义(P>0.05).(3)两种方法T2和T3时点FRC较T0均增加(P<0.05),T1时点CS均有所改善(P<0.05),方法之间差异无统计学意义(P>0.05),Pplat在各时点差异均无统计学意义(P>0.05).结论 SI和PCV肺复张对ARDS患者PaO2、FRC、肺复张中Cs均有明显改善,肺复张对CI均有影响,两种方法效果相同.     

肺复张手法对急性肺损伤大鼠肺泡上皮细胞屏障功能的影响

目的 观察肺复张手法对急性肺损伤（ALI）大鼠肺泡上皮细胞屏障功能的影响。方法雄性清洁级SD大鼠48只，静脉注射脂多糖（LPS）复制ALI模型，随机分为对照组、ALI模型组（ALI组）、小潮气量（VT）通气组（LV组）和肺复张联合小VT通气组（SI组）。采用控制性肺膨胀（SI）实施肺复张手法。机械通气4h后，观察肺组织病理学改变；采用末端脱氧核苷酸转移酶介导的dUTP缺口末端标记法（TUNEL）检测肺泡上皮细胞凋亡情况；用重力法测定血管外肺水（EVLW）含量；用单核素示踪技术测定肺泡上皮细胞通透性改变；用逆转录-聚合酶链反应（RT—PCR）检测肺组织肺泡表面活性蛋白-C（SP—C）mRNA表达；用酶联免疫吸附法（ELISA）检测支气管肺泡灌洗液（BALF）中白细胞介素-6（IL-6）和IL-10浓度。结果 光镜下，SI组肺组织损伤程度轻于ALI组和LV组。LV组凋亡肺泡上皮细胞散在分布，SI组凋亡上皮细胞明显减少。与对照组相比，ALI组、LV组及SI组肺损伤评分和EVLW均显著升高；与ALI组比较，LV组和SI组肺损伤评分显著降低，SI组肺损伤评分及EVLW显著低于LV组（P均〈0．05）。与对照组相比，ALI组、LV组及SI组肺组织SP—C mRNA表达均显著降低，而SI组肺组织SP—C mRNA表达显著高于LV组（P〈0．05），但与ALI组比较差异无显著性。ALI组、LV组和SI组BALF中IL-6和IL-10浓度均显著高于对照组（P均〈0．05），SI组IL-6浓度显著低于LV组（P〈0．05）。各组肺泡上皮细胞通透性间比较差异均无显著性。结论 肺复张手法可以减轻ALI肺组织病理损伤，增加肺泡上皮细胞SP—C mRNA的合成，下调肺部炎症反应，改善肺泡上皮细胞屏障功能。     

不同麻醉用药对重症颅脑损伤患者氧分压及代谢的影响

目的探讨三种不同麻醉方法对重症颅脑损伤患者氧分压及代谢的影响。方法 78例颅脑重症损伤患者分为A组(丙泊酚静脉全凭麻醉)、B组(七氟烷吸入全麻)和C组(静吸复合全麻)。比较3组患者于麻醉前(T_0)、插管前即刻(T_1)、插管后2 min(T_2)、手术开始后10 min(T_3)、手术开始后30 min(T_4)及术毕(T_5)时的有创血压平均动脉压(MAP)、心率(HR)、颈内静脉血氧含量(Cjv O2)、桡动脉血氧含量(Ca O2)、脑氧摄取率(CERO2)。结果与T_0、T_1比较,3组患者T_2~T_5的MAP均显著下降(F=5.112、4.040、4.301,P=0.0002、0.0018、0.0011)。麻醉后,3组患者Sjv O2均显著上升(F=3.833、3.322、8.114,P=0.0027、0.0071、0.0001),Da-jv O2均显著降低(F=3.127、2.635、4.886,P=0.0094、0.0258、0.0004),CERO2均显著减小(F=14.37、8.805、25.72,P0.01)。结论丙泊酚静脉全凭麻醉、七氟烷吸入全麻和静吸复合全麻均具有良好的脑保护作用。