瓣膜置换术围体外循环期血浆胶体渗透压的控制

目的比较以血浆和4%琥珀酰明胶作为预充液的患者围体外循环期血浆胶体渗透压(COP)的变化。方法 43例在体外循环下行瓣膜置换术患者,分为血浆预充组(A 组)和4%琥珀酰明胶预充组(B 组),检测患者麻醉后、体外循环后5 min COP,体外循环中维持 COP>16 mmHg。比较分析预充液 COP 与患者体外循环后 COP 的关系。结果体外循环后5 min,两组 COP 较麻醉后明显下降.与预充液 COP 呈正相关。B 组体外循环后5 min COP 明显高于 A 组。结论预充液COP 维持较高水平(>20 mm Hg)可以使患者体外循环期间 COP 达到有效水平。4%琥珀酰明胶预充维持 COP 较血浆更有优势。     

6%羟乙基淀粉130/0.4体外循环预充对心脏手术患儿血浆胶体渗透压及乳酸水平的影响

目的 探讨6%羟乙基淀粉130/0.4(6% HES130/0.4)体外循环预充对心脏手术患儿血浆胶体渗透压(COP)和乳酸水平的影响.方法 心脏直视手术患儿40例,性别不限,年龄≤6岁,随机分为2组(n=20):对照组和6% HES130/0.4组.于主动脉阻断前即刻、主动脉阻断5 min、停机前即刻、术毕时取桡动脉血2 ml,测定乳酸浓度、氧分压(PaO2)、二氧化碳分压(PaCO2)、pH值、血红蛋白(Hb)、红细胞压积(Hct)、平均动脉压(MAP)和鼻咽温.于麻醉诱导前、体外循环5 min、体外循环30 min、常规超滤前即刻、停机即刻和人ICU 2 h时取桡动脉血1ml,采用WESCOR4420型胶体渗透压仪测定COP.结果 与对照组比较,6% HES130/0.4组乳酸浓度降低,COP升高(P＜0.05或0.01).2组乳酸浓度主动脉阻断后升高,停机前即刻达高峰,术毕有所下降,但仍较主动脉阻断前即刻升高(P＜0.01).2组COP体外循环期间降低,入ICU 2 h时升高(P＜0.01).结论 6% HES130/0.4心脏手术患儿体外循环预充可提高血浆COP,降低血浆乳酸水平.     

逆行自体血预充方法用于心肺转流先心病手术血液保护的效果

目的探讨逆行自体血预充技术(RAP)在心肺转流(CPB)先心病手术中的血液保护效果。方法 20例先心病手术患者,随机分为对照组(n=10)和RAP组(n=10)。对照组采用常规的预充方法,RAP组采用逆行自体血预充技术。记录CPB前、CPB 15min、停CPB后1h、术后24h的Hb、Hct和血乳酸(Lac),并记录预充液量、术中用血量、呼吸机辅助时间、ICU停留时间等。结果两组患者均成功进行CPB心脏手术,无患者死亡,无输血相关并发症。RAP组预充液量明显少于对照组(P0.01)。CPB 15 min和停CPB后1hRAP组Hb和Hct均明显高于对照组(P0.05);停CPB后1h和术后24hRAP组Lac明显低于对照组(P0.05)。RAP组围术期用血量明显少于对照组(P0.05)。结论在CPB先心病手术中使用RAP技术可以有效的减少预充液量,减低CPB过程中的血液稀释,改善组织灌注,减低呼吸机辅助时间,减少术中用血量。     

两种胶体预充液用于心肺转流的临床研究

目的研究羟乙基淀粉和琥珀酰明胶用于心肺转流(CPB)预充时对患者凝血功能及胶体渗透压的影响。方法 60例先天性非紫绀心脏病患者,随机均分为两组:羟乙基淀粉组以6%羟乙基淀粉130/0.4预充,琥珀酰明胶组以4%琥珀酰明胶预充。手术室及ICU根据分组情况亦分别输注羟乙基淀粉和琥珀酰明胶。于CPB前、给鱼精蛋白后、ICU6h测定激活凝血时间(ACT)、凝血速率(CR)及血小板功能(PF);于CPB前、CPB中、CPB后、ICU2h和6h测定胶体渗透压。结果给鱼精蛋白后和ICU6h,羟乙基淀粉组PF明显高于琥珀酰明胶组(P<0.05),其余指标差异无统计学意义。结论 6%羟乙基淀粉130/0.4与4%琥珀酰明胶作为胶体预充液在心肺转流中使用安全性相似。     

库血预充液零平衡超滤对婴幼儿体外循环中炎性反应的影响

目的观察在婴幼儿心内直视手术中库血预充液采用零平衡超滤(ZBUF)后对机体炎性反应的影响。方法20例体重<10kg、在体外循环(CPB)下行心内直视手术的婴幼儿,按随机数字表法分为两组。对照组(n=10):常规采用库血预充;ZBUF组(n=10):在常规库血预充的基础上对预充液进行ZBUF,晶体预充液及平衡置换液均选用复方氯化钠溶液,ZBUF时间12.00±1.25 min,滤液量共300ml。对比超滤前后预充液的改变,观察CPB过程中两组患者血流动力学、炎性因子及生化等指标的改变。结果ZBUF组在常规库血预充液混合、采用ZBUF300ml后,其二氧化碳分压(PCO2)、K+、乳酸(LAC)、葡萄糖(GLU)、肿瘤坏死因子α(TNF-α)和白细胞介素8(IL-8)均较对照组低,氧分压(PO2)较对照组高(P<0.01)。CPB过程中两组患者平均动脉压(MAP)、血浆TNF-α和血GLU比较差别无统计学意义(P>0.05),而LACI、L-8浓度和带管时间ZBUF组低于或短于对照组(P<0.05,0.01)。结论ZBUF可以滤除CPB库血预充液中的炎性介质、K+、LAC和GLU,经ZBUF调整后的库血预充液在维持CPB期间的血流动力学和保护重要器官功能方面具有一定的作用。     

成分库血在婴幼儿体外循环预充中的应用

目的探讨婴幼儿体外循环中减少库血用量的方法。方法将小于3岁的先天性心脏病患者160例分成实验组（n＝80）和对照组（n＝80）,实验组在体外循环预充时加入浓缩红细胞,对照组加入全血。结果实验组患者在体外循环中应用浓缩红细胞量240±80ml,胶体（血定安）400±101ml;对照组患者在体外循环预充中应用库血量400±96ml,血浆190±57ml;实验组用血量明显减少,而两组患者术后的恢复情况无明显差别。结论成分库血在体外循环预充中可明显提高红细胞压积,不影响患者术后恢复,并可以明显减少库血用量。     

国产聚明胶肽作为心肺转流胶体预充液的安全性和对血液流变学的影响

目的 研究国产聚明胶肽注射液与羟乙基淀粉130/0.4氯化钠注射液作为心肺转流(CPB)胶体预充液的安全性和对血液流变学的影响.方法 择期CPB手术患者60例随机分为两组:A组(n=29)预充国产聚明胶肽1 000 ml和复方乳酸钠;B组(n=31)预充羟乙基淀粉130/0.4氯化钠注射液1 000 ml和复方乳酸钠.分别于CPB前、CPB开始后10 min和复跳后测定血浆渗透压及血钾、钠、镁、钙浓度;观察CPB中尿量及术后1 d晨尿量;检测CPB前、CPB中及术后2 h血液流变学参数等.结果 (1)CPB中A组的尿量明显多于B组;CPB前、CPB开始后10 min和复跳后血浆胶体渗透压及血钾、钠、镁和钙离子浓度各时点差异均无统计学意义.(2)两组患者的清醒及拔管时间、次日晨胸腔引流量、血压、氧分压、术后库血及血浆使用量差异无统计学意义.(3)两组患者全血黏度1.0、30、180,还原黏度1.0、30、180,Hct、刚性指数、聚集指数及变形指数在各时点差异均无统计学意义.结论 国产聚明胶肽与羟乙基淀粉130/0.4氯化钠注射液作为CPB胶体预充液的临床效果基本一致.     

体外循环中控制胶体渗透压的初步探讨

为了探讨在体外循环中如何合理控制胶体渗透压的水平，我们应用胶渗压测定仪，对２８例患者术前测血液胶渗压，对不同胶体配置的体外循环预充液和体外循环中不同时间段胶渗压进行监测，并对常用预充的胶体液进行胶渗压测定。还将２８例患者按应用血定安组与应用其它胶体组行统计学分析，在胶渗压达到要求水平方面，其精确概率Ｐ＝０．００５，差异有极显著意义。作者认为：为达到合理的胶渗压水平，预充液需要考虑配置胶体质和量的要求：（１）胶体选择：人造代血浆血定安或７０６的胶渗压约５．３３ｋＰａ（４０ｍｍＨｇ），单独使用即可使预充液有效达到所需胶渗压水平；人血白蛋白主要缺点为价格昂贵，难以广泛大量使用。全血和血浆不能使预充液胶渗压达到有效的水平；（２）７０６或血定安在预充液中的比率＞１／２时，预充液胶渗压可达到要求的水平。     

体外循环中人工胶体预充对体重低于5 kg先天性心脏病患儿术后凝血功能影响的研究

目的探索在先天性心脏病(先心病)手术体外循环(CPB)中,用人工胶体替代人血白蛋白作为胶体预充液对体重低于5 kg的先心病患儿凝血功能的影响。方法纳入2016年9月至2017年12月在我院行先心病手术体重低于5 kg患儿65例,随机分为两组:人工胶体预充组(试验组,n=33)和人血白蛋白复合人工胶体预充组(对照组,n=32)。监测患儿围术期血红蛋白浓度(Hb)、血制品和止血药物使用量、术后凝血功能指标、术后24 h胸腔积液量等。结果两组患儿围术期Hb和24 h胸腔积液量差异无统计学意义(P0.05)。试验组关胸期间血小板使用率显著低于对照组(P0.05)。两组患儿围术期其他血制品和止血药物使用量差异无统计学意义,术前及术后24 h凝血指标差异也无统计学意义(P0.05)。结论在体重低于5 kg先心病患儿矫治术中,用人工胶体完全替代人血白蛋白作为体外循环胶体预充液未对患儿围术期凝血功能产生不良影响。     

婴幼儿心脏手术采用全胶体预充的临床观察

目的　观察婴幼儿心脏直视手术中 ,体外循环应用全胶体预充液对术中和术后液体平衡、出血和输血量的影响。　方法　收集全胶体预充前后先天性心脏病患者临床资料 15 1例 ,分别作为对照组和全胶体预充组 ,比较两组患者血液制品用量、胸腔引流液量、术中和术后液体出入情况以及临床恢复情况。　结果　全胶体预充组白蛋白用量多 ,术中超滤量、液体入量和尿量较少 ,术后速尿用量多 ;其余差别无显著性意义。　结论　婴幼儿体外循环全胶体预充有利于减少术中的液体入量     

股静脉测压法和膀胱测压法在危重患者腹内压监测中的比较

目的：比较股静脉测压法和膀胱测压法在危重患者腹内压（IAP）监测中的应用价值.方法：对2013年1-6月住院治疗的20例ICU重症患者,分别使用两种测压方法进行IAP监测,均每8 h 1次,连续测定3 d,每次随机选择两种方法的测量顺序,共测量720次,比较两种测压法在读数精准性、测压数值、操作时间、并发症和医护人员满意度等方面的异同.结果：股静脉测压法所测压力数值与膀胱测压法相近[（14.14±4.33）mmHg比（12.91±4.75）mmHg,P〉0.05];但是股静脉测压法的操作时间[（57.94±19.00）s]较膀胱测压法更短[（112.49±27.07）s,P〈0.05];股静脉测压法读数精准率（84.44%）较膀胱测压法（49.44%）高（P〈0.01）,操作并发症低至1.1%（4例次）,远低于膀胱测压法的5.3%（19例次,P〈0.05）;医护人员满意度达（3.90±0.26）分,优于膀胱测压法[（2.48±0.19）分,P〈0.01].结论：相对于膀胱测压法而言,股静脉测压法具有测压值相似、操作时间短、读数精准度高、操作并发症少、接纳度高等优点,值得在危重患者IAP监测中推广.     

间歇正压通气和呼气末正压通气对犬眼内压的影响

目的 探讨间歇正压通气(IPPV)和呼气末正压通气(PEEP)对犬眼内压(10P)的影响.方法 实验犬8只,麻醉后分别监测基础条件下和各种机械通气条件下的IOP、CVP、MAP.结果 实施20 ml/kg和30 ml/kg两种不同潮气量的IPPV时IOP差异无统计学意义.实施10、15、20cm H20三种不同压力值的PEEP时IOP均显著升高(P<0.01).结论 IPPV对IOP影响不大,PEEP可使IOP显著升高.     

Iliac venous pressure estimates central venous pressure after laparotomy

Background

Central venous pressure (CVP) is traditionally obtained through subclavian or internal jugular central catheters; however, many patients who could benefit from CVP monitoring have only femoral lines. The accuracy of illiac venous pressure (IVP) as a measure of CVP is unknown, particularly following laparotomy.

Methods

This was a prospective, observational study. Patients who had both internal jugular or subclavian lines and femoral lines already in place were eligible for the study. Pressure measurements were taken from both lines in addition to measurement of bladder pressure, mean arterial pressure, and peak airway pressure. Data were evaluated using paired t-test, Bland-Altman analysis, and linear regression.

Results

Measurements were obtained from 40 patients, 26 of which had laparotomy. The mean difference between measurements was 2.2 mm Hg. There were no significant differences between patients who had laparotomy and nonsurgical patients (P = 0.93). Bland-Altman analysis revealed a bias of 1.63 ± 2.44 mm Hg. There was no correlation between IVP accuracy and bladder pressure, mean arterial pressure, or peak airway pressure.

Conclusions

IVP is an adequate measure of CVP, even in surgical patients who have had recent laparotomy. Measurement of IVP to guide resuscitation is encouraged in patients who have only femoral venous catheter access.     

Intra-abdominal pressure measurement: validation of intragastric pressure as a measure of intra-abdominal pressure

Background: The diagnosis of abdominal compartment syndrome depends uponthe demonstration of an elevated intra-abdominal pressure (IAP).Direct measures of IAP are impractical in the critical careunit; intravesical pressure (IVP) and intragastric pressure(IGP) should represent acceptable surrogate measures. IVP isthe preferred measure of IAP in critical care. We consideredthat IGP represents a practical alternative. The objective ofthis preliminary study was to observe the relationship betweenIGP and IAP. Methods: After Institutional Ethics Board approval, 29 patients havingelective laparoscopic surgery were recruited. IAP was measureddirectly via the abdominal trochar. This was compared with IGPmeasured via a commercial balloon catheter placed into the stomach. Results: Measured IGP was always more positive than IAP; both showedlinear correlation (r²>0.9). When IGP was calibrated againstIAP, an estimated difference between the IGP and IAP of ±2.5 mm Hg for 95% of the measurements was seen. Conclusions: The study demonstrates the strength of the relationship betweenIGP and IAP in normal individuals. Application of IGP measurementin the critical care patient is necessary to demonstrate itssuitability for continuous IAP assessment.     

Changes in intracranial pulse pressure amplitudes after shunt implantation and adjustment of shunt valve opening pressure in normal pressure hydrocephalus

Summary Background  We have previously reported that the intracranial pulse pressure amplitudes were elevated in idiopathic normal pressure hydrocephalus (NPH) patients responding to shunt surgery. Whether or not shunt implantation or adjustment of the shunt valve opening pressure modifies the intracranial pulse pressure amplitudes in NPH patients remains to be established. This report summarises our observations. Patients and methods  Thirteen patients with NPH (idiopathic in nine and secondary in four) are presented in whom continuous intracranial pressure (ICP) monitoring was done before and after shunt implantation. In two, ICP monitoring was also done during adjustment of shunt valve opening pressure. The mean ICP and mean ICP wave amplitude (i.e. pulse pressure amplitudes) were determined in 6-s time windows. Results  After shunt implantation there was a fall in both mean ICP and mean ICP wave amplitude; the reduction in the two ICP parameters correlated significantly. However, mean ICP in the supine position was normal (i.e. <15 mmHg) in 12 of 13 patients before shunt placement, and remained normal after shunting. According to our criteria, the mean ICP wave amplitudes were elevated before shunting in 12 of 13 patients and became “normalised” the day after shunting in nine patients. The reduction in mean ICP wave amplitude after shunt was highly significant at the group level. Moreover, adjustment of shunt valve opening pressure modified the levels of mean ICP wave amplitudes. Conclusions  The present observations in 13 NPH patients indicate that shunt implantation reduces mean ICP wave amplitudes. Moreover, the level of reduction can be tailored by adjustment of the shunt valve opening pressure.     

Telemetric recording of intrapleural pressure

BACKGROUND: Monitoring of intrapleural pressure (IPP) is used for evaluation of lung function in a number of pathophysiological conditions. We describe a telemetric method of non-invasive monitoring of the IPP in conscious animals intermittently or continuously for a prolonged period of time. MATERIALS AND METHODS: After IACUC approval, six mongrel dogs were used for the study. After sedation, each dog was intubated and anesthetized using 0.5% Isoflurane. A telemetric implant model TL11M2-D70-PCT from Data Science International was secured subcutaneously. The pressure sensor tip of the catheter from the implant was inserted into the pleural space, and the catheter was secured with sutures. The IPP signals were recorded at a sampling rate of 100 points/second for 30 to 60 min daily for 4 days. From these recordings, the total mean negative IPP (mmHg), and the total mean negative IPP for a standard time of 30 min were calculated. In addition, the actual inspiratory and expiratory pressures were also measured from stable recording of the IPP waveforms. RESULTS: In six dogs, the total mean +/- SD negative IPP was -10.8 +/- 10.6 mmHg. After normalizing with respect to acquisition time it was -13.2 +/- 11.2 mmHg/min. The actual inspiratory pressure was -19.7 +/- 15.3, and the expiratory pressure was -11.0 +/- 12.9. CONCLUSIONS: Our study demonstrates that telemetric monitoring of IPP can be performed reliably and non-invasively in conscious experimental animals. The values for IPP in our study are compatible with the results of other investigators who used different methods of IPP measurement. Further work may show this method to be helpful in understanding the pathophysiology of various breathing disorders.     

Associations between intracranial pressure, intraocular pressure and mean arterial pressure in patients with traumatic and non-traumatic brain injuries

Introduction

Anatomical proximity of the eye and the intracranial space is a fact but the existence of physiological and pathophysiological relationships between them is elusive. The objective of this study was to explore anatomical and pathophysiological interactions between the eye and the intracranial space and to assess clinical utility of intraocular pressure measurement in estimation of intracranial pressure in patients with brain injuries and to discover how haemodynamic instability could influence these interactions. Controversy surrounds the recent literature concerning this problem and the consensus has not been achieved.

Materials and methods

We evaluated the correlation between intracranial pressure and intraocular pressure, intracranial pressure and mean arterial pressure, intraocular pressure and mean arterial pressure in 40 patients with brain injuries initially comatose, admitted to our hospital. All patients required the intracranial pressure monitoring on clinical grounds. Simultaneous recordings of intracranial pressure, intraocular pressure and mean arterial pressure were performed.

Results

We calculated both the linear correlation coefficient and the Spearman rank-order correlation coefficient for all three relations. We found significant correlation between intraocular pressure and mean arterial pressure in 63% of the tested population. When the power of the test was increased, by considering only patients with 11 or more observations, this ratio increased to 76%. However, the correlation between intraocular pressure and intracranial pressure, as well as, between intracranial pressure and mean arterial pressure was not significant.

Conclusions

There is no anatomical and pathophysiological basis for the statement that intraocular pressure can be used as an indirect estimator of intracranial pressure.     

Our contemporary understanding of the aetiology of pressure ulcers/pressure injuries

In 2019, the third and updated edition of the Clinical Practice Guideline (CPG) on Prevention and Treatment of Pressure Ulcers/Injuries has been published. In addition to this most up‐to‐date evidence‐based guidance for clinicians, related topics such as pressure ulcers (PUs)/pressure injuries (PIs) aetiology, classification, and future research needs were considered by the teams of experts. To elaborate on these topics, this is the third paper of a series of the CPG articles, which summarises the latest understanding of the aetiology of PUs/PIs with a special focus on the effects of soft tissue deformation. Sustained deformations of soft tissues cause initial cell death and tissue damage that ultimately may result in the formation of PUs/PIs. High tissue deformations result in cell damage on a microscopic level within just a few minutes, although it may take hours of sustained loading for the damage to become clinically visible. Superficial skin damage seems to be primarily caused by excessive shear strain/stress exposures, deeper PUs/PIs predominantly result from high pressures in combination with shear at the surface over bony prominences, or under stiff medical devices. Therefore, primary PU/PI prevention should aim for minimising deformations by either reducing the peak strain/stress values in tissues or decreasing the exposure time.     

Blood pressure assessment in haemodialysis patients: Comparison between pre-dialysis blood pressure and ambulatory blood pressure measurement

Aim: Hypertension is common in haemodialysis (HD) patients. Determining the most appropriate method of blood pressure (BP) measurement, representative of target organ damage, is still an issue. BP variations between pre‐ and post‐HD treatment, or between on‐dialysis day and off‐dialysis day, are common. The aim of this study was to examine the possible differences between pre‐HD office BP (OBP) levels, inter‐HD (iHD) or HD day 24 h ambulatory BP measurement (ABPM) with 48 h ABPM, where the latter was considered the gold standard. Methods: 163 HD patients were studied. BP was monitored consecutively for 48 h with a Takeda TM2421 device, then sub‐analysed into two periods of 24 h: HD and iHD day. An average of 12 sessions pre‐HD OBP measurements was determined. Results: OBP significantly overestimates systolic (SBP) and diastolic BP (DBP) when compared with 48 h ABPM. SBP and DBP are significantly higher on iHD day than on HD day: 141.2 ± 20.8 versus 137.9 ± 20.9, and 77.1 ± 11.1 versus 76.1 ± 10.9 (P < 0.01). No differences of SBP night/day ratio were reported between 48 h ABPM and iHD 24 h ABPM or HD 24 h ABPM. The highest correlations were reported between 48 h SBP/DBP with iHD or HD 24 h ABPM (r² = 0.95, P < 0.001), while the lowest between 48 h SBP/DBP and OBP (r² = 0.40, P < 0.01, r² = 0.12, P < 0.01). The narrowest limits of agreement using the Bland and Altman test were reported between 48 h SBP or DBP and 24 h iHD or HD day ABPM. Considering 48 h ABPM, 80.5% of patients had BP higher than the norm, compared with 61.7% of patients in the case of OBP (χ² = 13.28, P < 0.001). The sensibility for detecting hypertension for iHD day 24 h ABPM was 98.4%, with specificity of 90%. The sensibility of 24 h HD day ABPM was 90.3%, with specificity 96.6%. In the case of OBP, sensibility and specificity were considerably lower, that is, 72.6% and 83.3% respectively. Conclusion: Significant differences are shown between OBP and 48 h ABPM in the recognition of a hypertensive state. OBP measurement has a lower sensibility and specificity than 24 h ABPM, which remains a valid alternative approach to 48 h ABPM in HD patients. Errors of OBP estimation should be taken into account, with possible negative impact on treatment strategies and epidemiology studies.