控制性肺膨胀对急性呼吸窘迫综合征家兔的肺力学和肺损伤影响

目的　探讨控制性肺膨胀 (SI)对急性呼吸窘迫综合征 (ARDS)家兔的肺力学和肺损伤影响。方法　利用肺泡灌洗法建立家兔ARDS模型 ,30只ARDS家兔随机分为SI组和非SI组。观察SI后 2h ,家兔肺力学及肺损伤的改变。结果　与非SI组相比 ,SI组在实施SI后 10、 30min ,1、 2h的平均气道压均明显降低。SI组 2h时的峰值气道压亦明显低于非SI组。与SI前比较 ,SI组实施SI后动态肺顺应性 (Cdyn)显著增加 ,SI前Cdyn为 (0 82± 0 11)ml/cmH2 O ,SI结束时达到最大 [(2 2 3± 0 4 )ml/cmH2 O],SI后 3h[(1 0 0± 0 0 6 )ml/cmH2 O]仍显著高于SI前水平。与非SI组比较 ,SI组 2h、 3h和 4h的Cdyn 均明显增加。非SI组肺损伤评分为 6 7± 2 6 ,SI组肺损伤评分显著降低 (5 0± 2 2 ,P <0 0 1)。结论　SI具有改善ARDS肺顺应性、防止肺损伤的作用     

醒脑静注射液联合无创正压机械通气治疗慢性阻塞性肺疾病急性发作期的临床研究

目的 :观察醒脑静注射液联合面罩无创机械通气 (NIPPV)治疗慢性阻塞性肺疾病 (COPD)急性发作期的临床疗效。方法 :对 35例 COPD急性发作期患者采用醒脑静注射液联合 NIPPV治疗 (中西医结合治疗组 ) ,并与单用 NIPPV治疗的 32例 COPD急性发作期患者 (对照组 )进行比较。结果 :中西医结合治疗组总有效率高于对照组 (91.4 %比 81.3% ,P<0 .0 5 ) ;中西医结合治疗组治疗后血气分析示动脉血氧分压 (Pa O2 )的升高幅度大于对照组〔(0 .86± 0 .0 5 ) k Pa(1k Pa=7.5 mm Hg)比 (0 .6 9± 0 .32 ) k Pa,P<0 .0 5〕,动脉血二氧化碳分压 (Pa CO2 )的下降幅度明显大于对照组〔(1.10± 0 .0 7) k Pa比 (0 .86± 0 .0 3) k Pa,P<0 .0 1〕;中西医结合治疗组治疗前后患者由意识障碍转为清醒状态所用时间要明显短于对照组〔(10 5 .0 0± 5 .5 2 )分钟比 (135 .0 0±6 .13)分钟 ,P<0 .0 1〕。结论 :醒脑静注射液联合 NIPPV治疗 COPD急性发作期患者疗效可靠 ,方便易行     

静态肺压力-容积曲线确定最佳呼气末正压的比较性试验研究

目的　通过静态肺压力 -容积曲线 (P -Vcurve)法和最大氧分压 (PEEPtrail)法确定不同PEEP对急性肺损伤家兔模型肺机械力学、氧代谢、血流动力学及病理学方面的影响 ,探讨最佳PEEP(BestPEEP)的确定方法。方法　采用内毒素诱导的家兔急性肺损伤 (ALI)模型 ,根据P -V曲线低位转折点 (Pinf)和PEEPtrail法确定PEEP水平 :Pinf- 2cmH2 O、Pinf、Pinf+2cmH2 O以及Ptrail,观察不同水平PEEP对ALI家兔肺机械力学、氧代谢、血流动力学及病理学的影响。结果　Ptrail和Pinf分别为 (15 8± 2 5 )cmH2 O和 (10 2± 2 1)cmH2 O差异显著 (P >0 0 5 )。虽然Ptrail组PaO2 显著高于Pinf组和Pinf+2cmH2 O组 ,但是Ptrail组心脏指数及氧输送指数均显著低于Pinf组和Pinf+2cmH2 O组 (P <0 0 5 )。Pinf组及Pinf+2cmH2 O组肺静态顺应性显著高于Ptrail组和Pinf- 2cmH2 O组 ,且Pinf组及Pinf+2cmH2 O组肺损伤指数显著低于Ptrail组和Pinf - 2cmH2 O组 (P <0 0 1)。结论　根据P -V曲线法确定PEEP是选择最佳PEEP的理想方法。Pinf或Pinf+2cmH2 O为最佳PEEP ,可获得最大肺顺应性和最大氧输送 ,而肺损伤最小。     

控制性肺膨胀对急性呼吸窘迫综合征绵羊肺力学和肺损伤的影响

目的：探讨控制性肺膨胀（SI）与肺保护性通气策略联合应用时，对急性呼吸窘迫综合征（ARDS）的肺泡复张作用及其安全性。方法：利用内毒秀导的绵羊ARDS模型，观察实施SI[2.94kPa(1kPa=10.20cmH2O)，屏气时间20秒]后绵羊的肺力学和组织病理学改变。结果：实施SI后，绵羊的动态肺顺应性和肺容积显著增加，气道峰值压、平台压和平均气道压均显著降低（P均＜0．05），并可维持3－4小时。与未应用SI的绵羊比较，实施SI后的绵羊肺损伤减轻，肺不张改善。结论：SI具有肺复张和肺保护作用，是肺保护性通气策略的重要补充。     

肺源性和非肺源性ARDS患儿早期氧合功能和静态肺顺应性的比较

目的:探索肺源性和非肺源性急性呼吸窘迫综合征(ARDS)早期患儿在不同呼气末正压(positive end expiratory pressure,PEEP)时氧合功能和静态肺顺应性的差异。方法:选取2012-08-2015-06我院PICU住院的ARDS患儿73例,分为肺源性ARDS组(ARDSp,35例)和非肺源性ARDS组(ARDSexp,38例),分别在PEEP水平为0、5、10、15cmH2O时记录动脉血气参数PaO_2、PaCO_2、PaO_2/FiO_2和静态肺顺应性。在肺保护性通气治疗下比较二者在肺氧合功能和静态肺顺应性之间的差异。结果:1随着PEEP的增加,2组患儿PaO_2和PaO_2/FiO_2均呈上升趋势,且ARDSexp组PaO_2和PaO_2/FiO_2均要高于ARDSp组,当PEEP=15cmH_2O时,2组比较差异有统计学意义(P0.05);22组PaCO_2在不同PEEP水平无明显变化;3在同一PEEP水平时,ARDSp组静态肺顺应性低于ARDSexp组,随着PEEP的增加,ARDSp组静态肺顺应性呈下降趋势,ARDSexp组则呈上升趋势,二者在PEEP水平为15cmH_2O时静态肺顺应性比较,差异有统计学意义(P0.05)。结论:机械通气可有效改善肺源性和非肺源性ARDS早期患儿氧合功能,当PEEP=15cmH_2O,非肺源性ARDS较肺源性ARDS氧合改善更明显,且能改善非肺源性ARDS静态肺顺应性。     

呼气末正压对急性呼吸窘迫综合征肺复张容积及氧合影响的临床研究

目的　评价呼气末正压 (PEEP)对急性呼吸窘迫综合征 (ARDS)肺复张容积的影响 ,探讨ARDS患者 PEEP的选择方法。方法　以 11例血流动力学稳定、接受机械通气的 ARDS患者为研究对象 ,采用压力容积曲线法分别测定 PEEP为 5、10、15 cm H2 O(1cm H2 O=0 .0 98k Pa)时的肺复张容积 ,观察患者动脉血气、肺机械力学和血流动力学变化。结果　 PEEP分别 5、10和 15 cm H2 O时肺复张容积分别为 (4 0 .2±15 .3) ml、 (12 3.8± 4 3.1) ml和 (178.9± 4 3.5 ) m l,随着 PEEP水平的增加 ,肺复张容积亦明显增加 (P均 <0 .0 5 )。动脉氧合指数也随着 PEEP水平增加而增加 ,且其变化与肺复张容积呈正相关 (r=0 .4 83,P<0 .0 1)。不同 PEEP条件下 ,患者的肺静态顺应性无明显变化 (P>0 .0 5 )。将患者按有无低位转折点 (L IP)分为有 L IP组与无 L IP组 ,两组患者的肺复张容积都随着 PEEP水平的增加而增加 ,其中 PEEP15 cm H2 O时 L IP组患者的肺复张容积大于无 L IP组 (P<0 .0 5 )。结论　 PEEP水平越高 ,肺复张容积越大 ,肺复张容积增加与动脉氧合指数的变化呈正相关     

肺保护性通气对肺内外源性急性呼吸窘迫综合征外周血和肺泡灌洗液中炎性介质影响的比较

目的　观察在肺保护性通气条件下急性呼吸窘迫综合征 (ARDS)模型犬氧合指数以及外周血和肺不同部位 (肺上区、肺下区腹侧和肺下区背侧 )支气管肺泡灌洗液 (BAL F)中炎性介质的变化。方法　健康雄性杂种犬 2 4只 ,随机分为肺内源性 ARDS(ARDSp)实验组、ARDSp 对照组、肺外源性 ARDS(ARDSexp)实验组和 ARDSexp对照组 ,每组 6只。采用静脉注射油酸形成 ARDSexp模型 ,应用十六烷磺基丁二酸钠盐气管内吸入形成 ARDSp模型。实验组肺损伤后进行肺保护性通气〔潮气量 8ml/ kg,呼气末正压(PEEP) 10 cm H2 O(1cm H2 O=0 .0 98k Pa)〕;对照组则继续进行大潮气量通气。动态观察肺保护性通气条件下 ARDS模型犬外周血和肺不同部位 (如肺尖叶、肺心叶和肺膈叶 ) BAL F中的炎性介质 ,如肿瘤坏死因子α(TNFα)、白细胞介素 (IL 1β,IL 6 )的变化。结果　肺损伤后 ARDS模型犬氧合指数均显著恶化 ,外周血中炎性介质明显升高 (P均 <0 .0 5 ) ,ARDSp模型犬肺尖叶和心叶 BAL F中炎性介质水平明显高于 ARDSexp模型犬 (P均 <0 .0 5 )。应用肺保护性通气治疗后 ,实验组犬氧合指数有不同程度改善 ,炎性介质水平有不同程度下降 ;但 ARDSp实验组的治疗效果不如 ARDSexp实验组。结论　 ARDSexp和 ARDSp的肺不同部位炎性介质释放和氧合     

急性呼吸窘迫综合征患者血清Clara细胞蛋白16表达及与肺顺应性关系

目的探讨行有创机械通气治疗急性呼吸窘迫综合征(acute respiratory distress syndrome,ARDS)患者血清Clara细胞蛋白16(Clara cell protein 16,Cc16)表达及与肺顺应性的关系。方法行有创机械通气治疗ARDS患者69例(观察组),同期行有创机械通气治疗非ARDS患者51例(对照组),采用ELISA法检测2组有创机械通气治疗3h内血清Cc16水平,并记录肺顺应性、呼吸频率、气道平均压、气道峰压、潮气量及呼气末正压(positive end expiratory pressure,PEEP),Pearson相关法分析血清Cc16水平与肺顺应性等指标的相关性。结果观察组有创机械通气治疗3h内血清Cc16[(59.25±17.62)ng/L]、气道峰压[(21.50±5.73)mm Hg]、气道平均压[(11.64±3.43)mm Hg]、PEEP[(4.42±1.67)cm H_2O]]、呼吸频率[(22.05±6.37)次/min]均高于对照组[(31.47±20.49)ng/L、(17.29±4.26)mm Hg、(8.67±1.74)mm Hg、(3.67±0.80)cm H_2O]、(18.54±5.63)次/min](P0.05),肺顺应性[(37.74±13.59)mL/cm H_2O]]低于对照组[(50.64±24.99)mL/cm H_2O]](P0.05),潮气量[(466.44±110.93)mL]与对照组[(445.17±105.50)mL]比较差异无统计学意义(P0.05);Pearson相关分析结果显示,观察组有创机械通气治疗3h内血清Cc16水平与肺顺应性呈负相关(r=-0.252,P=0.036),与呼吸频率、潮气量、气道峰压、气道平均压及PEEP无线性相关(r=-0.015,P=0.835;r=-0.171,P=0.902;r=-0.007,P=0.816;r=-0.026,P=0.865;r=0.068,P=0.783);对照组有创机械通气治疗3h内血清Cc16水平与PEEP呈正相关(r=0.281,P=0.046),与肺顺应性、潮气量、呼吸频率、气道峰压及气道平均压无线性相关(r=-0.018,P=0.612;r=-0.148,P=0.536;r=-0.109,P=0.928;r=0.019,P=0.653;r=0.077,P=0.537)。结论 ARDS患者肺顺应性降低,且与血清Cc16水平呈负相关。     

吸入一氧化氮联合反比通气治疗感染性急性呼吸窘迫综合征

目的 :观察吸入一氧化氮 (NO)联合反比通气 (IRV)对感染性急性呼吸窘迫综合征 (ARDS)羊血流动力学、肺气体交换和机械力学的影响。方法 :静脉注入小剂量内毒素诱导的羊感染性 ARDS模型 12只 ,随机均分为两组。 NO组吸入 4 0× 10 - 6 NO,复合组联合容量控制反比通气 (VC IRV)和吸入 4 0× 10 - 6 NO。通过肺动脉导管、动脉和混合静脉血气分析 ,测定基础、ARDS和治疗 30 m in后肺气体交换和血流动力学参数 ,记录相应时间点的气道峰压 (PIP)、平均气道压 (Pm)和内源性呼气末正压 (PEEPi)。结果 :NO组和复合组治疗期间平均肺动脉压较 ARDS时均显著降低 (P均 <0 .0 1) ,动脉血压和心排血量则无明显变化 ;治疗 30 m in后 ,两组均能明显提高 ARDS的 Pa O2 (P均 <0 .0 1) ,减少肺泡动脉氧分压差〔 P( A a) O2 〕和肺内分流 (Qs/ Qt,P均 <0 .0 1) ,复合组更为显著 (P均 <0 .0 5 ) ;NO组各监测时间点 PIP、Pm均无明显变化 ,复合组的 Pm较治疗前及NO组对应时间点高 (P均 <0 .0 5 ) ,PIP则低 (P均 <0 .0 5 )。复合组治疗时 ,PEEPi为 (2 .5± 0 .5 ) cm H2 O(1cm H2 O=0 .0 98k Pa)。结论 :吸入 NO复合 IRV可协同改善 ARDS肺氧合 ,不影响体循环。     

控制性肺膨胀在急性肺损伤中的应用

急性肺损伤／呼吸窘迫综合征（ALI/ARDS）是临床常见呼吸系统危重症，其治疗是以机械通气为基础的综合治疗。由于ALI/ARDS往往伴随大量肺泡萎陷，常规机械通气方法救治成功率较低。控制性肺膨胀（SI）是近年来应用较多的一种肺复张方法，机械通气时通过给予足够的气道压力并持续一定的时间，能够在一定程度上使塌陷的肺泡充分开放。大量的动物及临床研究表明，SI的应用能够在一定程度上提高ALI/ARDS时的氧合，改善肺顺应性，从而达到提高救治成功率的目的。     

应用最佳顺应性设定呼气末正压的临床研究

目的 以低流速法描记准静态压力-容积曲线(P-V曲线)选择最佳呼气末正压(PEEP)作为对照,观察滴定最佳顺应性方法选择最佳PEEP的临床实用性和安全性.方法 选取本院重症监护病房(ICU)2009年11月至2010年12月14例接受机械通气的急性呼吸窘迫综合征(ARDS)患者,分为两组,每组7例;分别使用低流速法描记准静态P-V曲线和滴定最佳顺应性的方法确定最佳PEEP,连续测量3次,比较各组所确定的最佳PEEP值和重复试验的一致性;观察试验前及试验后2、4、6h血流动力学参数、氧合指数(0I)、肺顺应性(C)以及血浆中细胞因子和肺表面活性蛋白D(SP-D)的变化.结果 ①两组性别、年龄、疾病严重程度等基础状态无明显差异.②准静态P-V曲线和滴定最佳顺应性方法确定的最佳PEEP值(cmH20,1 cm H2O=0.098 kPa)无明显差异(11.53±2.07比10.57±0.87,P＞0.05).但准静态P-V曲线描记的重复性差,3次描记的P-V曲线斜率呈逐渐下降趋势,每次确定的最佳PEEP值呈逐渐升高趋势,第3次与第1次描记比较差异有统计学意义(12.80±1.92比10.00±1.58,P＜0.05);而滴定最佳顺应性的方法重复性好,每次确定的最佳PEEP值无明显差异.③描记准静态P-V曲线后患者的心率(HR,次/min)、体温(℃)、白细胞介素-6(IL-6,ng/L)、肿瘤坏死因子-α(TNF-α,ng/L)、SP-D(μg/L)均呈逐渐升高趋势,平均动脉压(MAP,mm Hg,1 mm Hg=0.133 kPa)、连续心排血指数(CCI,L·min-1·m-2)、OI(mm Hg)及C(ml/cm H20)均呈下降趋势,均于试验后6h达峰值或谷值,与试验前比较差异有统计学意义(HR:117.34±8.53比93.71±5.38,体温:38.05±0.73比36.99±1.02,IL-6:144.84±23.89比94.73±5.91,TNF-α:151.46±46.00比89.86±13.13,SP-D:33.65±8.66比16.63±5.61,MAP:85.47±9.24比102.43±8.38,CCI:3.00±0.48比3.81±0.81,OI:62.00±21.45比103.40±37.27,C:32.10±2.92比49.57±7.18,均P＜0.05),提示准静态P-V曲线的描记会加重原有肺损伤;而滴定最佳顺应性试验前后患者HR、MAP、体温、CCI、OI、C、细胞因子及SP-D均无明显差异.结论 滴定最佳顺应性方法确定最佳PEEP重复性好,临床操作更简单、更安全,便于临床开展.     

无创正压通气压力支持水平对呼吸音的影响

目的:研究不同压力支持水平对正常健康人肺部呼吸音的影响。方法:选取20例健康成人,利用肺部振动反应成像系统(VRIxp)采集正常呼吸及配带口鼻面罩无创呼吸机辅助呼吸时的呼吸音图像变化。观察不同压力支持水平(0、2、4、8cmH2O)时最大能量桢图像、平均灰度值及吸气相曲线斜率变化。结果:健康人在正常呼吸时及压力支持水平分别为2、4、8cmH2O(PS-2,PS-4、PS-8)时最大呼吸音能量图面积分别为:(7.97±0.31)、(8.16±0.41)、(8.14±0.48)和(8.39±0.43)平方英寸,PS-8与其他压力支持水平间差异有统计学意义(P<0.05);吸气相曲线斜率分别为:1.26±0.41、1.13±0.27、1.17±0.24和1.42±0.31,PS-8与其他压力支持水平间差异有统计学意义(P<0.05)。平均灰度值分别为:96.96±8.47、96.48±13.02、94.46±10.34和96.92±13.65,不同压力支持水平间差异无统计学意义(P>0.05)。结论:无创呼吸机压力支持水平为8cmH2O时较2和4cmH2O改善通气作用明显。     

Volume/pressure curve of total respiratory system in paralysed patients: artefacts and correction factors

The volume/pressure (V/P) curve of the total respiratory system in paralysed patients is drawn assuming that volume changes of the respiratory system (V resp) equals volume displacement of the measuring apparatus (V syr), usually a supersyringe. However, in 93 VP curves we found that O₂ removed from the lung-syringe system during the procedure (proportional to the time) largely exceedes the CO₂ added to the lung-syringe system (V gas). This results in a net loss of volume from the system (V resp相似文献   

Application of a computerised method to measure static pressure volume curve in acute respiratory distress syndrome

Objective: To assess the safety and the bedside feasibility of a new computerised method to record the static pressure-volume curves (Pst/V) of the respiratory system.¶Design: The Pst/V curves were recorded in 13 medical patients with the acute respiratory distress syndrome (ARDS). During the Pst/V curve tracing the following parameters were recorded: time required for the recording and the automatic analysis of the Pst/V curve and modifications in electrocardiograms, blood pressure, and arterial oxygen satmation (SaO₂).¶Setting: The study was performed in the intensive care unit of the University of Naples “Federico II”.¶Results: No statistically significant modifications in heart rate (HR, b min^–1), blood pressure (BP, mmHg), and SaO₂ were observed between conditions at baseline (HR 97.2 ± 17.7; BP 65.4 ± 9.3; SaO₂ 93.6 ± 2.0), during the recording (HR 99.8 ± 19.5; BP 66.2 ± 11.6; SaO₂ 93.7 ± 2.4), and 2 min after the procedure (HR 98.2 ± 17.8; BP 65.2 ± 11.7; SaO₂ 93.7 ± 1.9). The Pst/V curves were recorded in 8.38 ± 1.19 min and fully analysed in 2.69 ± 0.85 min. Mean value of static compliance was 41.1 ± 12.7 ml cmH₂O^–1. A lower inflection point was found in ten patients (mean value 9.2 ± 1.9 cmH₂O).¶Conclusions: In ARDS patients, the present new computerised method gave valuable data to ordinary intensivists and was shown to be safe, easy, and fast.     

Use of total inspiratory pressure-volume curves for determination of appropriate positive end-expiratory pressure in newborns with hyaline membrane disease

Thirty newborns with hyaline membrane disease were treated by mechanical ventilation with individualized appropriate positive end-expiratory pressure (APEEP) from inspiratory pressure-volume curves of the total respiratory system. APEEP was started before H 24 in group 1(19 patients), and after H24 in group 2 (11 patients). Until APEEP, the 2 groups had classical PEEP levels (lower than 0.8 kPa) either without or with incomplete improvement in arterial hypoxia. The mean APEEP of each group was greater than classical PEEP (P<0.001). In group 1 the time of exposure to F_iO₂>0.4 was shorter (23.8±13.7 h) than in group 2 (88.6±56.9 h) (p<0.001) and rapid improvement in blood gas exchanges was seen in group 1 compared to group 2 that was independant of the severity of the disease. Tolerance was excellent. APEEP ventilation started before H24 is of special interest in the management of newborns with severe alveolar injury.     

吸气与呼气压力-容积曲线对确定最适呼气末正压的比较性研究

目的 根据吸气与呼气压力-容积曲线(P-V曲线)确定呼气末正压(PEEP),探寻最适PEEP治疗急性呼吸窘迫综合征(ARDS)的方法.方法 20只ARDS模型犬按配对随机法分成两组.用软件根据列文伯格-马夸尔特算法(Levenberg-Marquardt iterative algorithm)求解Boltzmann公式参数,根据公式计算P-V曲线呼气支真正拐点压力(Pinf d)或吸气支相应的低位转折点压力(Plip)值.对照组(吸气支)应用P-V曲线Plip+2 cm H2O(1 cm H2O=0.098 kPa)作为最佳PEEP值;实验组(呼气支)应用P-V曲线Pinfd作为最佳PEEP 值.两组分别监测0、2、6、12、24及48 h的心率(HR)、血压(BP)、指尖脉搏血氧饱和度(SpO2)、肺静态顺应性(Cst)、动脉血氧分压(PaO2)及动脉血二氧化碳分压(PaCO2).结果 两组ARDS模型犬氧合指数均明显升高,实验组监测12、24、48 h时氧合指数(mm Hg,1 mm Hg=0.133 kPa)明显高于对照组(12 h:177.63±8.94比165.60±8.90,24 h:194.19±10.67比168.70±10.60,48 h:203.15±13.21比171.26±9.21,均P＜0.01);监测2、6、12、24及48 h Cst(ml/cm H2O)明显高于对照组(2 h:41.00±4.17比36.20±3.90,6 h:44.00±4.65比36.88±3.39,12 h:46.92±5.47比37.92±3.10,24 h:42.83±8.97比37.92±3.09,48 h:42.64±9.04比37.97±2.98,P＜0.05或P＜0.01).结论 根据P-V曲线呼气支确定最佳PEEP治疗ARDS较吸气支更优.     

Heterogeneity hampers the identification of general pressure injury risk factors in intensive care populations: A predictive modelling analysis

ObjectiveTo determine risk factors for pressure injury in distinct intensive care subpopulations according to admission type (Medical; Surgical elective; Surgery emergency; Trauma/Burns).Methodology/designPredictive modelling using generalised linear mixed models with backward elimination on prospectively gathered data of 13 044 adult intensive care patients.Settings1110 intensive care units, 89 countries worldwide.Main outcome measuresPressure injury risk factors.ResultsA generalised linear mixed model including admission type outperformed a model without admission type (p = 0.004). Admission type Trauma/Burns was not withheld in the model and excluded from further analyses. For the other three admission types (Medical, Surgical elective, and Surgical emergency), backward elimination resulted in distinct prediction models with 23, 17, and 16 predictors, respectively, and five common predictors only. The Area Under the Receiver Operating Curve was 0.79 for Medical admissions; and 0.88 for both the Surgical elective and Surgical emergency models.ConclusionsRisk factors for pressure injury differ according to whether intensive care patients have been admitted for medical reasons, or elective or emergency surgery. Prediction models for pressure injury should target distinct subpopulations with differing pressure injury risk profiles. Type of intensive care admission is a simple and easily retrievable parameter to distinguish between such subgroups.     

Systolic pressure variation and pulse pressure variation during modifications of arterial pressure

OBJECTIVE: This study was performed to investigate the effect of vasopressor therapy on systolic pressure variation (SPV) and pulse pressure variation (PPV) compared to experimentally measured left ventricular stroke volume variation (SVV). DESIGN AND SETTING: Prospective study in a university laboratory. SUBJECTS: Twelve anesthetized and mechanically ventilated pigs. INTERVENTIONS: Increase in mean arterial pressure (by 100%) using phenylephrine and decrease (by 38%) using adenosine. MEASUREMENTS AND RESULTS: SPV and PPV were calculated and compared to SVV derived from aortic blood flow measurements. SPV was significantly affected by changes in arterial pressure [4.6% (1.5) vs. 6.3% (2.1), p[Symbol: see text]<[Symbol: see text]0.05, increased vs. decreased arterial pressure], whereas PPV did not change during modifications of arterial pressure. During baseline conditions and decreased afterload, correlation with SVV was good both for SPV (r[Symbol: see text]=[Symbol: see text]0.892 and r[Symbol: see text]=[Symbol: see text]0.859, respectively) and for PPV (r[Symbol: see text]=[Symbol: see text]0.870 and r[Symbol: see text]=[Symbol: see text]0.871, respectively) (all p[Symbol: see text]<[Symbol: see text]0.001). Correlation with SVV was only moderate during increased arterial pressure (r[Symbol: see text]=[Symbol: see text]0.683 for SPV and r[Symbol: see text]=[Symbol: see text]0.732 for PPV, p[Symbol: see text]<[Symbol: see text]0.05). CONCLUSION: For guiding fluid therapy in patients under vasopressor support, PPV seems superior to SPV.     

Effect of positive end-expiratory pressure on intra-abdominal pressure

Massive elevation of intra-abdominal pressure (IAP) causes renal, cardiovascular, and respiratory dysfunction. Positive end-expiratory pressure (PEEP) markedly increases the detrimental effect of IAP on the cardiovascular system. The purpose of this study was to determine the effect of PEEP on IAP. In 15 patients requiring mechanical ventilation, IAP was measured, after 15-minute equilibration intervals, at PEEP levels of 0, 5, 10, and 15 cm H2O. Parametric analysis with multiple paired t tests and nonparametric analysis with Spearman's rho and Kendall's tau tests were used to determine correlation between PEEP and IAP. All patients were male. The mean age was 39 years (range, 18-77). Ten patients had just had laparotomy. No correlation was found between PEEP and IAP. We conclude that PEEP of 15 cm H2O or less has no effect on IAP, and we discuss the clinical implications.