无创测定临界关闭压变化率对高血压患者脑血管储备能力的评估价值

目的 无创测定临界关闭压变化率,并评价其对高血压者脑血管储备能力的评估价值.方法 招募符合入组标准的原发性高血压患者25例和健康志愿者35例为研究对象.用经颅超声多普勒仪、无创血压监测仪持续记录高血压组及对照组的大脑中动脉的血流流速和桡动脉血压,用潮气末CO2监测仪持续监测呼出气体的PCO2.高碳酸血症通过吸入混合气体(5%CO2、21%O2和74%N2)获得.用傅立叶变换法分别测得两组吸入混合气体前后的临界关闭压(CCP).分别计算两组吸入混合气体后流速增加率和CCP变化率.结果 两组试验对象的大脑中动脉平均流速、CCP在吸入混合气体前比较差异均无显著性意义(t=1.008,P=0.318;t=0.059,P=0.437).吸入混合气体后,高血压组的流速增加率低于对照组的流速增加率,差异有显著性意义(t=-4.325,P=0.000),但两组的CCP减少率比较差异无显著性意义(t=0.459,P=0.648).结论 传统的流速变化率对脑血管储备能力的评价要优于CCP变化率,进一步评价脑血管储备能力仍宜测定流速变化率.     

无创机械通气治疗AECOPD并重度高碳酸血症呼吸衰竭的疗效分析

目的总结经无创机械通气在慢性阻塞性肺病急性加重(AECOPD)并发重度高碳酸血症呼吸衰竭中的治疗经验。方法 76例COPD急性加重引起的重度高碳酸血症(PCO2>80mmHg)呼吸衰竭患者分为无创通气组与一般治疗组(对照组),观察临床症状改善的情况与动脉血气的变化。结果治疗后无创通气组动脉血二氧化碳分压较治疗前显著下降,而pH值和动脉血氧分压则较治疗前显著上升,对照组治疗前、后以上血气分析变化无显著性差异。无创通气组的临床症状改善优于对照组。结论经面罩机械通气对COPD急性加重引起的重度高碳酸血症呼吸衰竭患者,能够改善临床症状、改善二氧化碳潴留和低氧血症,减少气管插管的需要,有利于患者的恢复。临床使用方便,耐受性好,不良反应少,值得临床推广使用。     

NIPPV在AECOPD合并严重高碳酸血症中的应用

目的探讨无创正压呼吸机辅助通气（noninvasive positive pressure ventilation,NIPPV）在慢性阻塞性肺疾病急性加重期（acute exacerbation of chronic obstructive pulmonary disease,AECOPD）合并有严重高碳酸血症中的作用。方法将40例AECOPD合并严重高碳酸血症（pH〈7.35）的患者随机分为无创呼吸机治疗组（N,n=20）和常规治疗组（C,n=20）,比较2组治疗前后的动脉血气分析、呼吸频率、心率、血压、插管率、住院天数及病死率。结果治疗2h后N组患者pH值、PaCO2、呼吸频率、心率有明显改善,气管插管率明显下降（P〈0.05）,病死率无明显差异,平均住院时间比C组缩短（P〈0.05）。结论 NIPPV能够改善AE-COPD合并严重高碳酸血症患者的动脉血气指标,并能减少气管插管率及缩短住院天数。     

阻塞性睡眠呼吸暂停低通气综合征白天高碳酸血症相关因素的研究

目的 研究阻塞性睡眠呼吸暂停低通气综合征(OSAHS)伴白天高碳酸血症的患病率,并与白天不伴高碳酸血症患者资料进行比较,经相关和回归分析探寻导致白天高二氧化碳的影响因素,以提高对本病的认识.方法 对连续收集到的肺功能正常的110例OSAHS中29例伴白天高碳酸血症者(研究组)与白天元高碳酸血症者81例(对照组)进行比较,观察两组年龄、体重指数(BMI)、肺功能、白天血气、夜间动态血氧饱和度(SaO2)、多导睡眠图(PSG)的差别,并对与PaCO2有关的因素进行相关和回归分析.结果 两组一秒率(FFV1/FVC)差异无显著性(P＞0.05),研究组较对照组年轻,BMI、呼吸暂停低通气指数(AHI)较对照组高(P＜0.05).研究组白天PaO2显著低于对照组,PaCO2、[HCO3-]显著高于对照组(P＜0.001).研究组夜间平均SaO2(MSaO2)、最低SaO2(LSaO2)显著低于对照组,氧饱和度≤90%的时间占总监测时间的百分比(SIT90)显著高于对照组(P＜0.05).高碳酸血症组白天PaCO2与MSaO2、LSaO2呈负相关(r值分别为-0.625;-0.429),与SIT90、AHI呈正相关(r值分别为0.563;0.385).经回归(逐步筛选法)分析,高碳酸血症组MSaO2可以解释引起白天PaCO2升高因素中的39.1%(R2=0.391,P=0.001).结论 OSAHS伴白天高碳酸血症的患病率为26.4%.伴白天高碳酸血症者多见于青年和中年患者并且较肥胖,夜间缺氧程度较白天无高碳酸血症者更为严重,提示病情较重.白天高碳酸血症与夜间缺氧有关,MSaO2是引起OSAHS白天高碳酸血症的重要因素之一,可将其作为OSAHS伴白天高碳酸血症的一个预测指标.     

经鼻持续气道正压通气治疗婴幼儿重症肺炎35例

目的研究经鼻持续气道正压通气(NCPAP)对重症肺炎合并心力衰竭(简称心衰)及Ⅱ型呼吸衰竭(简称呼衰)婴幼儿心肺功能的支持作用。方法重症肺炎合并心衰、Ⅱ型呼衰患儿35例在综合治疗基础上予应用NCPAP,观察NCPAP应用前后患儿呼吸频率、心率、血压、动脉氧分压(PaO2)、氧合指数(PaO2/FiO2)、二氧化碳分压(PaCO2)。结果应用NCPAP2小时后,患儿平均呼吸频率、心率、血压、PaO2、PaO2/FiO2有明显改善(P<0.01);PaCO2略下降,但与应用NCPAP前无显著性差异(P>0.05)。结论NCPAP可提高合并心衰及呼衰患儿肺氧合功能及左心泵功能,且不加重高碳酸血症。     

腹腔镜妇科手术的麻醉处理

目的 观察妇产科腹腔镜手术中二氧化碳气腹对患者循环、呼吸等生理变化的影响.方法 选择ASAⅠ～Ⅱ级的腹腔镜妇产科手术30例,所有患者均在气管内插管全麻下行腹腔镜手术,测定气腹前后循环、呼吸等变化.结果 SPO2等变化不明显,气腹后PETCO2明显上升(P＜0.01),气腹后MAP、HR较气腹前明显升高(P＜0.05),有显著性差异,气腹后气道阻力明显上升(P＜0.05).结论 通过30例妇产科手术的观察,选择全麻气管内插管的麻醉,既能保证良好的通气和氧合,又能控制膈肌运动,避免出现高碳酸血症.     

二氧化碳气腹对脑循环的影响

研究腹腔镜手术二氧化碳人工气腹对脑血流的影响。采用TC2020型TCD仪对19例胆囊炎胆石症患者于腹腔镜术中行脑血流动态监测。结果表明气暖时大脑中动脉平均流速无变化，脉动指数降低，血压升高，气腹后脉动指数，收缩压迅速恢复正常，舒张压恢复较慢。结论：腹腔镜手术时二氧化碳人工气腹对脑血流无影响。     

幼儿腹腔镜手术时预防高碳酸血症的临床研究

目的探讨幼儿腹腔镜手术时预防高碳酸血症的方案。方法选择接受腹腔镜手术，体征约10k左右患儿40例，随机将其分为A、B两组，设定使用相同的9mmHg气腹压力，A组改变呼吸通气参数提前进行麻醉干预，B组选择通常呼吸通气参数进行麻醉，观察末梢二氧化碳分压及心率改变，同时对比两组发生二氧化碳潴留的机率并记录两组相关数据。结果提前麻醉干预组术中血气二氧化碳分压、心率和呼末二氧化碳大致正常，而进行正常呼吸通气参数麻醉麻醉组血气二氧化碳分压、心率和呼末二氧化碳高于干预组（P〈0．05）。结论腹腔镜手术对小儿的呼吸、循环及血气虽有较大影响，但通过改变呼吸通气参数提前进行麻醉干预，对预防高碳酸血症有积极意义。     

盐酸右美托咪定在肺性脑病患者行无创机械通气治疗中的护理

肺性脑病(PE)是因各种慢性肺胸疾病引发呼吸功能衰竭,导致低氧血症和高碳酸血症而出现各种神经精神症状的一种临床综合征。无创机械通气是纠正患者缺氧和二氧化碳潴留的重要治疗措施。但患者出现各种神经精神症状时往往不能很好的配合无创呼吸机的使用。盐酸右美托咪定注射液     

无创通气在急性左心衰并发低氧血症抢救中的应用

目的探讨无创机械通气在急性左心衰并发低氧血症抢救中的临床意义。方法对42例急性左心衰并发低氧血症的患者在常规内科治疗同时加用无创性经面罩机械通气(NIV)治疗,观察无创通气(NIV)前后患者呼吸指标、肺气体交换与心率(HR)、平均动脉压(MAP)的变化。结果42例患者均能耐受NIV治疗,临床症状明显改善,呼吸频率明显下降;与NIV治疗前相比,患者的动脉血中PH、氧分压(PaO_2)、二氧化碳分压(PaCO_2)、氧饱和度(SaO_2)等指标明显改善(P<0.05),HR与MAP明显减慢(P<0.05)。结论NIV治疗急性左心衰时能迅速改善患者的症状和低氧血症,是一种快速、安全、有效的方法,可避免气管插管。     

The effect of rebreathing and hyperventilation on retinal and choroidal vessels measured by spectral domain optical coherence tomography

Objective: The purpose of this study was to examine the vasoreactivity in retina and choroid of the healthy eyes in response to experimentally altered partial arterial pressure of carbon dioxide (PaCO₂) using a non-invasive technique, spectral domain optical coherence tomography (SD-OCT).

Materials and methods: The study included non-smoking participants between 18 and 35 years of age, having visual acuity of 20/20 and with no systemic and ocular diseases. At baseline, the participants breathed room air (normocapnia). Hypocapnia was created with the help of hyperventilation; for this, the participants were instructed to draw deep and quick breaths, resulting one breathing cycle per 2?s. To create hypercapnia subjects rebreathed from a 5?l bag at least 3?min. Choroidal thickness and retinal artery diameter were measured at baseline, and hyperventilation and rebreathing conditions by SD-OCT.

Results: Twenty eyes of 20 healthy subjects were included in this study. Their mean age was 24.90?±?5.32 years. Hyperventilation caused a significant reduction in choroidal thickness, compared with baseline, at all points; whereas rebreathing caused no significant change at all points. The mean diameters of the arteries were 151.80?±?7.88?μm, with a significant decline to 148.90?±?7.25?μm at hyperventilation condition and a significant increase to 153.50?±?7.88?μm at rebreathing condition (p?=?0.018, p?=?0.043, respectively).

Conclusion: This study demonstrated that, SD-OCT was a useful tool in measuring the ocular vascular response under hypercapnia and hypocapnia conditions. These findings may be helpful for further understanding the physiological nature of ocular blood flow and this preliminary study provides a basis for future studies.     

Effects of CO2 to modulate the norepinephrine constrictor response in isolated perfused rabbit carotid artery

It has been suggested that large cerebral arteries contribute to cerebral vascular resistance and thus participate actively in the regulation of cerebral blood flow (CBF) during changes in arterial carbon dioxide tension (PCO2). In order to test this hypothesis, 3-cm segments of carotid artery from adult male rabbits were studied. The segments were mounted in a chamber with constant surrounding pressure and temperature and perfused at constant pressure. Inflow pressure, outflow pressure, and outflow rate were measured and values of resistance (R) were calculated before (C) and after stimulation with two sequential norepinephrine concentrations: 4 X 10(-6) M (NE1), 1 X 10(-5) M (NE2). During each sequence, the PCO2 of the surrounding and perfusion media were held equal and constant at one of four levels. The following mean R values were obtained: (table; see text) Symbols (*) represent significance (p less than 0.05) between the indicated R and the corresponding normocapnic (PCO2 = 35 mm Hg) R. Hypercapnia (PCO2 = 61 mm Hg) enhanced the response to both NE1 and NE2. Moderate hypocapnia (PCO2 = 27 mm Hg) had no effect. These studies support the claim that large cerebral arteries contribute to CBF regulation during PCO2 changes. However, the effect of large cerebral arteries may not be significant during PCO2 variations of less than 20 mm Hg.     

Increased Cerebral Blood Flow And Cardiac Output Following Cerebral Arterial Air Embolism In Sheep

1. The effects of cerebral arterial gas embolism on cerebral blood flow and systemic cardiovascular parameters were assessed in anaesthetized sheep. 2. Six sheep received a 2.5 mL injection of air simultaneously into each common carotid artery over 5 s. Mean arterial blood pressure, heart rate, end-tidal carbon dioxide and an ultrasonic Doppler index of cerebral blood flow were monitored continuously. Cardiac output was determined by periodic thermodilution. 3. Intracarotid injection of air produced an immediate drop in mean cerebral blood flow. This drop was transient and mean cerebral blood flow subsequently increased to 151% before declining slowly to baseline. Coincident with the increased cerebral blood flow was a sustained increase in mean cardiac output to 161% of baseline. Mean arterial blood pressure, heart rate and end-tidal carbon dioxide were not significantly altered by the intracarotid injection of air. 4. The increased cardiac output is a pathological response to impact of arterial air bubbles on the brain, possibly the brainstem. The increased cerebral blood flow is probably the result of the increased cardiac output and dilation of cerebral resistance vessels caused by the passage of air bubbles.     

脉压/平均动脉压比率预测脑出血的可行性研究

目的通过对脑出血患者发病时脉压和脉压／平均动脉压比率与对照组的比较，探讨脉压／平均动脉压比率预测脑出血的可行性。方法选取脑出血患者108例，测定入院时的首次血压（不受治疗因素影响），计算其脉压（PP）、脉压／平均动脉压比率（PP／MAPRatio），与年龄、性别匹配的健康对照组102例的PP、PP／MAP Ratio进行比较、分析。结果脑出血组的PP、PP／MAP Ratio显著高于对照组（PP：χ^2=196．000，PP／MAP Ratio：χ^2=249．771，P〈0．01），PP、PP／MAP Ratio分布频率与对照组差异有统计学意义（PP：χ^2=87．469，PP／MAP Ratio：χ^2=18．960，P〈0．01）。全部病例进人Logstic回归分析，PP≥50 mmHg者脑出血发病的危险性是PP低于50mmHg者的5倍（0R=5．000，95％CI为2．642～9．461）；PP／MAP Ratio高于0．45者脑出血是PP／MAP Ratio低于0．45者的2．6倍（0R=2．647，95％CI为1．516～4．622）。PP〉50mmHg、PP／MAP Ratio〉0：45，脑出血的发病率明显增大。结论PP／MAP Ratio也和PP-样都可以用于预测脑出血发病的危险性，PP／MAP Ratio是无量纲值，具有可比性，因此优于PP。     

经鼻间歇正压通气与气管插管同步间歇正压通气治疗新生儿呼吸窘迫综合征的疗效与安全性比较

目的：探讨经鼻间歇正压通气与气管插管同步间歇正压通气治疗新生儿吸窘迫综合征的疗效与安全性。方法选择60例新生儿科住院治疗的RDS且需要呼吸支持的患儿,按随机数字表法平均分为气管插管同步间歇正压通气组（ SIPPV＋VG组）和经鼻间歇正压通气组（ NIPPV组）,每组30例。两组患儿均应用肺表面活性物质（ PS）替代治疗,并记录呼吸支持0 h、12 h、24 h、72 h吸入氧浓度（ FiO2）、二氧化碳分压（PaCO2）、氧分压（PaO2）、平均气道压（MAP）、血氧饱和度（SaO2）,计算P/F（PaO2/FiO2）、动脉/肺泡氧分压比值（ a/APO2）,并分析两组间治疗后的疗效与安全性。结果两组间0 h、12 h、24 h、72 h后MAP、FiO2和P/F（ PaO2/FiO2）差异均有统计学意义（ F＝153．247、187．385、376．587、128．509、430．276、259．507,均P＜0.05）,且0 h分别与12 h、24 h、72 h的差异亦均有统计学意义（均P＜0．05）;PaO2、SaO2、a/APO2在两组间差异均有统计学意义（F＝732．756、987．835、796．37、683．508、735．375、679．509,均P＜0．05）,且0 h分别与12 h、24 h、72 h的差异亦均有统计学意义（均P＜0．05）;VAP和气漏在两组间比较差异有统计学意义（ P＝0.039,0．021）。结论两种方法均能有效提高NRDS患儿氧合状态、促进气体交换功能,NIPPV法可进一步减少VAP、气漏的发生率,是临床上首选的无创机械通气方法。     

EFFECTS OF INDOMETHACIN ON STEROID-INDUCED CHANGES IN PRESSOR RESPONSIVENESS IN MAN

1. It has been shown previously that hydrocortisone (F) increases pressor responsiveness in normal subjects. The present study examined the role of vasodilator prostanoids in determining these changes. 2. Pressor responsiveness to angiotensin II (AII) (1-8 ng/kg per min) and phenylephrine (PE) (0.3-0.9 microgram/kg per min) was examined in six normal men receiving: no treatment (day 1); 100 mg indomethacin p.o. (INDO) in three divided doses over 20 h (day 2); 200 mg F for 5 days, 50 mg 6 hourly p.o. (day 6); F plus 100 mg INDO (day 7). 3. Blood pressure, body weight and plasma glucose rose with F and plasma potassium fell. F alone produced significant increases in response to AII at 2 ng/kg per min, for systolic pressure (SBP), diastolic pressure (DBP) and mean arterial pressure (MAP), and at 1 ng/kg per min for DBP. The threshold for SBP, DBP and MAP rises with AII was decreased by F. Responses to PE following F were greater at 0.6 microgram/kg per min for SBP, DBP and MAP and the threshold for all parameters fell. 4. INDO alone had no significant blood pressure or metabolic effects and no effect on the magnitude of the blood pressure rise with AII, but decreased the threshold dose for effects on MAP. INDO had no effect on the magnitude of the pressure rise with PE, but decreased the threshold dose for effects on SBP. 5. INDO did not modify responsiveness or threshold to AII following F. Responsiveness to PE was unchanged and threshold fell for SBP only during INDO.(ABSTRACT TRUNCATED AT 250 WORDS)     

Differential vasoactive effects of sildenafil and tadalafil on cerebral arteries

Phosphodiesterase 5 (PDE5) is associated with migraine pathophysiology, stroke recovery and vasospasm treatment. The potential vascular interplay of PDE5 inhibitors sildenafil, tadalafil and UK-114,542 was studied by intra- versus extra-luminal administration in rat middle cerebral arteries in vitro and on middle meningeal arteries in vivo. By Western blot PDE5 was detected in both cerebral and meningeal arteries, though with minor variations in band intensity between vascular beds. Rat middle cerebral artery diameter was investigated using pressurised arteriography, applying UK-114,542, sildenafil, and tadalafil intra- or extra-luminally. Effects on the dural middle meningeal artery were studied in the in vivo closed cranial window model. At high concentrations, abluminal sildenafil and UK-114,542, but not tadalafil, induced dilatation of the middle cerebral artery. Luminal application elicited a contraction of 4% (sildenafil, P=0.03) and 10% (tadalafil, P=0.02). In vivo, sildenafil, but not tadalafil, dose-dependently dilated middle meningeal artery concomitant to blood pressure reduction (1-3mg/kg);1mg/kg sildenafil inducing 60 ± 14% (P=0.04) and vehicle (DMSO) 13 ± 6% dilatation. In conclusion, PDE5 inhibitors applied luminally had minor contractile effect, whereas abluminal sildenafil induced middle cerebral artery dilatation above therapeutic levels. In vivo, sildenafil dilated middle meningeal artery concomitant with a reduction in blood pressure. Tadalafil had no dilatory effects. PDE5 inhibitors show differential vascular activity in cerebral arteries from healthy animals; arterial dilatation is seen primarily above therapeutic levels. Such findings support clinical studies showing no vasodilator effects of sildenafil on cerebral arteries in healthy subjects.     

硝普钠控制性降压对呼气末动脉二氧化碳分压差-生理无效腔影响

目的：观察硝普钠(SNP)控制性降压对呼气末与动脉二氧化碳分压差［P(a ET)CO2］及生理无效腔(Vdphys/Vt)的影响。方法：鼻窦手术患者20例，入室后快速诱导气管内麻醉，静吸复合维持麻醉。手术开始后静脉滴注硝普钠快速降压到平均动脉压(MAP)基础水平的50%～60%。分别于手术开始后10 min(降压即刻T0)，降压开始后20 min(T1)，40 min(T2)和停止降压后20 min(T3)，四个时相分别记录MAP、心率(HR)、Vt、PETCO2，并同步采集桡动脉血行血气分析。计算每时相的P(a ET)CO2以及Vdphys/Vt。结果：PETCO2 T1、T2时点明显低于T0时点(P＜0.01)。血压恢复后的T3时点与T0时点无差异(P＞0.05)。PaCO2下降约7%，但各时点比较差异无显著性(P＞0.05)。P(a ET)CO2 T1、T2时点明显高于T0时点(P＜0.01)。血压恢复后的T3时点与T0时点无差异(P＞0.05)。Vdphys/V T1、T2时点明显高T0时点(P＜0.01)。血压恢复后的T3时点与T0时点无差异(P＞0.05)。结论：SNP控制降压到MAP为基础值50%～60%时，Vdphys/Vt增加，P(a ET)CO2增加。PETCO2不能反映PaCO2水平。但PaCO2下降不明显，因此呼吸参数不需要改变。     

胎儿大脑中动脉血流峰速值对地中海贫血的诊断价值

目的：探讨多普勒超声检测胎儿大脑中动脉血流峰值速度对预测胎儿地中海贫血的临床价值。方法选取在产前检查夫妻双方为轻型或中间型地中海贫血患者90例的单胎孕妇为观察对象，同时选取同期接受多普勒超声检查的夫妻双方均无地中海贫血基因的单胎孕妇作对照组，统计两组孕妇在（22．0±3．0）孕周胎儿大脑中动脉血流动力学相关指标。结果重型地中海贫血胎儿大脑中动脉血流峰值速度平均为（52．06±11．03）cm/s，与对照组相比，差异有统计学意义（χ2＝348．20，P＜0．01），而重型地中海贫血胎儿博动指数、阻力指数及S/D与对照组相比，χ2分别为1．35、0．49、0．91，P均＞0．05，差异无统计学意义；轻型与中间型地中海贫血胎儿大脑中动脉血流峰值速度与对照组相比，χ2分别为1．63、5．79，P＞0．05，差异无统计学意义。结论多普勒超声测量胎儿大脑中动脉收缩期峰值速度预测地中海贫血有效、可靠、无创、可重复，拥有广泛的应用前景。