Throwing induces substantial torsional adaptation within the midshaft humerus of male baseball players

Athletes participating in unilateral dominant sports are useful models for investigating skeletal responses to mechanical loading as they provide controlled evidence in the absence of completing a randomized controlled trial. Throwing athletes may be an additional model for this purpose as they overload their dominant upper extremity enabling the contralateral side to act as an internal control and load the bones of the upper extremity purely via the generation of internal (i.e. muscular) forces without superposition of externally applied loads (i.e. impact with an external object). The aim of this study was to investigate upper extremity bone adaptation in throwing athletes and explore factors that predict this adaptation. Two cohorts were recruited—male baseball players (throwers; n = 15) and matched controls (controls; n = 15). Each subject was assessed for shoulder range and strength, and upper extremity bone mass, structure and estimated strength. Throwers had substantially greater skeletal differences between their dominant and nondominant upper extremities than controls, indicating that throwing induces greater adaptation than induced by habitual loading of the dominant upper extremity. Bone adaptation in throwers was localized to the humerus, with the midshaft humerus in the dominant upper extremity of throwers having enhanced bone mass, structure and estimated strength. The largest effect was for estimated strength of the midshaft humerus which had 30% greater polar moment of inertia (I_P) in throwers and suggests adaptation to resist torsional loads. The skeletal effect of throwing at the midshaft humerus was influenced by playing position with pitchers and catchers displaying greater dominant-to-nondominant differences than fielders, and was predicted by years throwing and dominant-to-nondominant difference in upper arm lean cross-sectional area. The latter two variables explained 67% of the variance in dominant-to-nondominant differences in I_P. Collectively, these data indicate that throwing induces substantial adaptation within the midshaft humerus. Adaptation was primarily in the direction of torsion which is consistent with biomechanical and injury data suggesting throwing introduces high magnitude torsional forces. As the magnitude of adaptation in throwers was equivalent to that observed in athletes participating in other unilateral dominant sports, throwers represent an alternative model for investigating the skeletal effects of mechanical loading.     

Ventilation imaging of the lung: Comparison of hyperpolarized helium-3 MR imaging with Xe-133 scintigraphy

RATIONALE AND OBJECTIVES: To compare hyperpolarized helium-3 (HHe) magnetic resonance imaging (MRI) of the lung with standard Xe-133 lung ventilation scintigraphy. MATERIALS AND METHODS: We performed a retrospective review of 15 subjects who underwent HHe MRI and Xe-133 lung ventilation imaging. Coronal MRI sections were acquired after a single inhalation of HHe gas, and standard posterior planar lung ventilation scintigraphy was performed during continuous breathing of Xe-133 gas. The first breath scintigram of each patient was compared with a composite MR image composed of the sum of the individual MR images and with the individual helium-3 MR images. Ventilation defects on the two imaging modalities were compared for size, conspicuity, and concordance in presence and location. Assessment was done separately for each of four lung quadrants. RESULTS: Comparing the composite HHe MR images with Xe-133 scintigraphy, ventilation defect size, conspicuity and concordance were the same in 67% (40/60), 63% (38/60), and 62% (37/60) quadrants, respectively. Comparing the individual HHe MR image sections with the Xe-133 ventilation scan, there was concordance between the ventilation defects in 27% (16/60) of quadrants. More defects were identified on the individual HHe MR images in 62% (37/60) of quadrants. CONCLUSION: There was good agreement between composite HHe MR image and first breath Xe-133 scintigraphic images, supporting the widely held assumption that HHe MRI likely depicts first breath lung ventilation.     

连续性静脉-静脉血液滤过联合机械通气治疗ARDS的临床观察

目的　观察连续性静脉 -静脉血液滤过 (CVVH)联合机械通气治疗ARDS患者的临床疗效。方法　选择入住ICU符合ARDS诊断标准的患者 4 0例 ,随机分为 2组 :A组 2 1例 ,采用常规治疗 +机械通气 ;B组 1 9例 ,采用常规治疗 +机械通气 +CVVH。分别观察 2组患者在使用呼吸机时间、氧合指数、吸入氧浓度、动脉血氧分压、PEEP水平、心率、血压及病死率等方面的差别。结果　A、B两组患者在病因、年龄、性别、APACHEⅡ评分及平均脏器功能障碍数等方面相似 ,B组患者加用CVVH后 ,各项指标经统计学处理显示 :病死率 ,B组与A组比较 ,差异有显著性意义 (P <0 0 5 ) :其他指标与A组比较 ,差异均有高度显著性意义 (P <0 0 1 )。结论　CVVH疗法可有效清除ARDS患者血管外肺水和各种应激激素、致炎介质 ,明显改善了ARDS患者肺部氧合功能及血流动力学指标 ,提高了抢救成功率     

CPAP对化疗后单肺通气时氧合及肺内分流的影响

[目的] 探讨应用一种新的持续气道正压 (CPAP)系统,对肺癌化疗后病人单肺通气时氧合和肺内分流的影响.[方法] 择期行肺癌手术病人 22例,按美国麻醉医师协会( ASA)分级, Ⅰ～Ⅲ级;随机分为对照组 (A组 )和 CPAP组 (B组 ),每组各 11例.A组在单肺麻醉期间非通气侧肺的支气管导管直接开口于大气中; B组单肺通气期间非通气侧持续给予 CPAP( P= 0.2 kPa),仰卧双肺通气 20 min, 仰卧单肺通气 20 min,侧卧单肺通气 30 min, 60 min,于关闭胸腔双肺通气时 ,分别采取动脉血样作血气分析,计算肺内分流率 (Qs/ Qt).[结果] 于单肺通气后 30 min和 60 min时 ,B组氧合明显高于 A组 (P < 0.01), B组分流率 (Qs/ Qt)明显低于 A组 (P < 0.05).[结论] 化疗后病人单肺通气期间 , 非通气侧持续 CPAP,有助于提高氧合 ,减少肺内分流 ,减少低氧血症的发生率.     

通用型脊柱内固定系统(GSS)在腰椎不稳症治疗中的近期疗效观察

目的 :观察GSS对腰椎节段性不稳的固定及治疗效果。方法 :2 0 0 2年 10月～ 2 0 0 3年 9月 ,对 2 5例腰椎不稳症患者。其中 ,男 9例 ,女 16例 ,运用椎板减压、椎管后外侧植骨融合、GSS椎弓根螺钉内固定系统治疗 ,随访 6～ 18个月 (平均 15 7个月 )。结果 :术前JOA评分平均 4 48分的 2 5例患者 ,随访时 14 5分 (P <0 0 1) ,术后 14个月内动态X线检查显示GSS椎弓根螺钉固定患者植骨融合率 10 0 % ,融合节段稳定 ,临床症状改善优良率 96 0 %。结论 :后路运用GSS行椎管后外侧植骨融合内固定对腰椎不稳症患者是一种安全、有效的术式 ,近期疗效满意     

内镜直视下机械扩张治疗贲门失弛缓症62例

目的评价内镜直视下机械扩张治疗贲门失弛缓症的疗效。方法利用自行设计并改良的机械扩张器械在上消化道内镜直视下对62例贲门失弛缓症进行机械扩张。其中1例为Heller手术失败，4例为气囊扩张失败。结果2例食管破裂中转开胸手术治愈；1例不能耐受手术而放弃；1例一次扩张效果不好，二次扩张后痊愈；其余58例一次成功。扩张时间2—5min，平均3．5min。术中均见黏膜少量出血，无活动性出血。术后2小时进冷流质饮食，6小时后软成形饮食，之后过渡为普通饮食。58例随访2—11年，平均7．5年，均获治愈。结论内镜直视下机械扩张贲门失弛缓症创伤小，费用低，无反流，长期随访效果可靠，有推广价值。     

肺内源性和肺外源性呼吸衰竭机械通气的临床对比研究

目的探讨肺内源性和肺外源性呼吸衰竭机械通气时的肺保护性策略。方法通过25例呼吸衰竭中12例肺内源性和13例肺外源性机械通气临床资料的回顾性分析,对比研究两组呼吸力学差异时对通气模式选择、参数设置和调节的影响,以及肺保护的实施方法。结果在两组APACHE-Ⅱ评分、平均年龄和Vt设置无差异的条件(P>005)下,肺内源性组PEEP/CPAP、PSV、f的需设值均明显高于肺外源性组(P<001)。肺内源性组Pplat、PIP、Raw的监测结果大于肺外源性组,而Crs小于肺外源性组(P<001)。肺内源性组417%和肺外源性组154%因MOF而死亡(APACHE-Ⅱ评分均>20分),组间比较有显著差异(P<001)。结论肺内源性和肺外源性呼吸衰竭机械通气时,实施肺保护的方法不同。前者应首选压力预置通气模式,后者可首选容量预置通气模式。以设置中、小Vt为原则,按个体化的通气需求而设置f和加用恰当的PSV、CPAP/PEEP对减少VILI、病死率可能有益。     

两种不同方法测定低水平压力支持通气时气道阻断压与自主呼吸时常规方法测定值的相关性分析

目的 拟比较以两种不同方法测定低水平压力支持通气（pressure support ventilation，PSV）病人的气道阻断压（P0．1）与自主呼吸时常规方法测定值的相关性。方法 12例机械通气病人，断开呼吸机自主呼吸时以常规方法测定P0．1得到P0．1-SB：在PSV水平为5cmH20，以常规方法和按压呼气末暂停键测定P0．1分别得到P0．1-PSV5和P0．1-PSV5eeo．分析后二者与前者之间的相关性。结果 P0．1-SB与P0．1-PSV5之间差异无显著性，P0．1-PSV5ee0分别小于P0．1-SB与P0．1-PSV5，差异有显著性；P0．1-PSV5eeo与P0．1-PSV5和P0．1-SB之间的相关系数均为0．97。结论 按压呼气末暂停键测定PSV水平为5cmH2O的P0．1值与常规方法测定的PSV水平为5cmH2O以及自主呼吸时的测定值相比，其值偏小,但前者与后二者之间具有良好的相关性。     

无创通气不同呼吸界面对COPD患者的生理学影响

目的 探讨无创正压通气(NPPV)时不同呼吸界面对慢性阻塞性肺疾病(COPD)急性加重期并呼吸衰竭患者的生理学影响.方法 选择30例COPD急性加重期并呼吸衰竭患者.无创正压通气时患者随机先后接受不同呼吸界面(面罩、鼻罩和鼻塞).动态观察不同呼吸界面时患者呼吸方式、血气分析和对呼吸界面耐受性等的差异.结果 (1)与自主呼吸相比,无创正压通气时三种不同呼吸界面均可改善患者的潮气量、分钟通气量和呼吸频率(P＜0.01),三种不同呼吸界面时的呼吸频率相似(P＞0.05),但面罩时的潮气量和分钟通气量比鼻罩时更高(P＜0.05);(2)与自主呼吸相比,无创正压通气时三种不同呼吸界面均可改善患者的动脉血气(P＜0.05),面罩和鼻塞时的PCO2比鼻罩时更低(P＜0.05);(3)患者均可耐受三种不同的呼吸界面,但患者对鼻罩的耐受性比面罩和鼻塞更好(P＜0.01).结论 本生理学研究证实了无创正压通气可改善COPD急性加重期并呼吸衰竭患者的呼吸方式和动脉血气,面罩和鼻塞时的疗效更佳,而鼻罩时的耐受性更好.     

应用无死腔气管插管提高正常和急性肺损伤兔的机械通气效率

目的：观察无死腔气管插管能否提高急性呼吸衰竭常规机械通气的效果。方法：应用一种新型无死腔气管插管和普通聚氯乙烯气管插管对正常和急性肺损伤兔进行常规通气，对两种气管插管的肺气体交换和气道内气体动力学及血流动力学变化进行比较。无死腔气管插管用２根Ｐｏｔｅｘ气管插管远端３ｃｍ处纵切后对粘而成。５只新西兰成年兔，麻醉下气管切开，在持续应用潘龙阻断自主呼吸条件下，随机用新型气管插管和普通气管插管Ｓｅｒｖｏ９００Ｃ进行机械通气，每次持续３０分钟，测定并记录动脉血压、气道压力、血流动力学参数和呼气末ＣＯ２浓度。结果：在正常肺和急性肺损伤条件下，新型气管插管可使所有动物的ＰａＣＯ２和生理死腔／潮气量（ＶＤ／ＶＴ）下降，ＰａＣＯ２分别下降１．４０±０．２０ｋＰａ（１ｋＰａ＝７．５ｍｍＨｇ）和１．６０±０．３０ｋＰａ（Ｐ＜０．０１），ＶＤ／ＶＴ分别下降０．１３±０．０２和０．１５±０．０４（Ｐ＜０．０１）；ＰａＯ２、气道压力和血流动力学无显著变化。结论：无死腔气管插管可明显提高常规机械通气效率。