呼气末正压对感染性休克患者心脏前负荷的影响

目的 探讨不同水平的呼气末正压(PEEP)对接受机械通气的感染性休克患者心脏前负荷的影响.方法 采用前瞻性、干预性的研究方法对北京协和医院MICU 15例行机械通气的感染性休克患者应用跨肺热稀释法及持续脉搏轮廓的方法进行血流动力学监测(PiCCOplus).所有患者采用容量控制通气,血流动力学稳定后,每隔1 h递增PEEP水平,PEEP从0增加20 cmH_2O(如果能耐受),根据不同的PEEP水平分为5组(0,5,10,15,20 cmH_2O).应用one-way ANOVA和Pearson's行统计分析及相关分析,观察在不同水平的PEEP对心脏前负荷的影响及其相关性.结果 15例感染性休克患者,男10例(67%),女5例(33%),年龄(67.6±19.5)岁,APACHEⅡ评分(22.1±7.5)分,基础PEEP水平(8.5±3.6)cmH_2O,基础PaO_2/FiO_2(225.6±89.2)mmHg,ICU病死率67%.随着PEEP的升高,CVP明显升高,不同水平的PEEP组差异具有统计学意义(p=0.002),而GEDI无明显变化,各组间差异无统计学意义.以PEEP0为基础值,不同PEEP水平的CVP,CI,GEDI与基础值之差为增量,发现△CI和△GEDI呈明显的正相关(r=0.6),而△CI和△CVP无明显的相关性.结论 在高PEEP存在的情况下,GEDI能够有效地评价心脏的前负荷.     

呼气末正压通气对冠脉搭桥术后机械通气时间的影响

目的：分析不同等级的呼气末正压通气( PEEP)值对冠脉搭桥术后机械通气时间的差异。方法回顾性收集苏州市某三级医院2013年1—11月进行冠脉搭桥84例患者的资料,根据呼气末正压值不同分为三组,PEEP值等于5 cmH2O为A组(n=26),PEEP值等于8 cmH2O为B组(n=28),PEEP值等于10 cmH2O为C组(n=30)。从护理记录中获取三组患者的机械通气时间并进行比较。结果术后入住ICU病房12 h内即拔管的患者中,A组机械通气时间为(7.3±2.4) h,B组为(7.6±2.7) h,C组为(6.8±3.2)h,各组机械通气时间差异有统计学意义(F=23.15,P<0.05)。结论冠脉搭桥术后选择合适的PEEP值有利于缩减冠脉搭桥患者的术后机械通气时间。     

呼气末正压通气对低血容量患者静脉回流压力阶差的影响

目的 观察呼气末正压(PEEP)对低血容量并机械通气患者中心静脉压(CVP)、髂总静脉压(CIVP)及两者差值[D(c-i)VP]的影响.方法 将2007年5月-2009年5月本院重症监护病房(ICU)收治的30例低血容量并机械通气患者随机分3组,分别实施0、5及10 cm H2O(1 cm H2O=0.098 kPa)的PEEP通气(分别为PEEP0、PEEP5、PEEP10),选择同期10例基本条件相似但血容量正常的机械通气患者作为对照组.测定患者CVP、CIVP,并计算D(c-i)VP;同时记录心率、平均动脉压及呼吸力学数据;对静脉压力变化与呼吸压力各指标进行相关性分析.结果 ①试验组CVP随PEEP升高而明显增加,PEEP0、5、10时CVP分别为(1.3±0.9)、(3.1±1.3)、(4.5±1.3)mm Hg(1 mm Hg=0.133 kPa,P均<0.01);而对照组CVP变化小,分别为(6.9±1.3)、(7.2±1.2)、(8.0±1.5)mm Hg,PEEP10时CVP显著高于PEEP0和PEEP5时(P<0.01和P<0.05).两组CIVP均随PEEP升高而升高,但升高幅度小于CVP.试验组D(c-i)VP较对照组明显增加(P均<0.01),但随PEEP升高有降低趋势,从PEEP0时的(4.9±1.7)mm Hg降至PEEP10时的(2.8±1.4)mmHg,而对照组变化不明显;3个PEEP水平下,D(c-i)VP值差异≤1.5mmHg.②试验组在PEEP0、5、10时CVP与CIVP均无相关性(r1=0.236,r2=0.299,r3=0.262,P均>0.05),而对照组均有相关性(r1=0.485,r2=0.679,r3=0.748,P均<0.05).结论 低血容量并机械通气加用PEEP患者,在PEEP升高时CVP及CIVP值的升高较对照组明显,此对利用两值来评估血容量及指导容量复苏均会造成很大影响.     

呼气末正压对机械通气患者中心静脉压及髂总静脉压的影响

目的 观察不同呼气末正压(PEEP)水平对机械通气患者中心静脉压(CVP)和髂总静脉压(CIVP)及两者相关关系的影响.方法 将2007年2-8月收住重症加强治疗病房(ICU),无心肺疾患、循环稳定、无腹胀、无凝血功能异常,需机械通气的20例成年患者列为观察对象,采用自身对照,随机加用0、5和10 cm HzO(1 am H2O=0.098 kPa)PEEP,评估在此条件下,CVP、CIVP和两者压力阶差变化及其与机械通气压力变化间的相关关系.结果 CVP及CIVP随PEEP增加而增高,差异有统计学意义(P0.05);CVP及CIVP与机械通气各压力值变化呈正相关,但CVP及CIVP仅与平均气道压(Pmean)及PEEP有统计学意义(CVP与PEEP r=0.751,CIVP与PEEP r=0.685,CVP与Pmean r=0.634,CIVP与Pmena r=0.603,P均相似文献   

呼气末正压对机械通气患者上腔静脉横径的影响

目的评价呼气末正压(PEEP)对机械通气患者的上腔静脉横径值(SVCD)的影响。方法受试的22例机械通气患者在不同水平PEEP(0～20 cm H_2O)时,应用多谱勒超声检查来监测其SVCD值,同时记录患者心率、平均动脉压与动脉血氧饱和度。统计学处理所有计量资料,以及SVCD与PEEP相关性分析。结果SVCD值随PEEP值增加而减少,且SVCD值的变化与PEEP值的变化呈显著性负相关(r=-0.981。)结论机械通气时SVCD值随PEEP值增加而减少,从而可用多普勒超声心动图检查来监测SVCD值以评价患者液体治疗效果。     

机械通气治疗后并发急性呼吸窘迫综合征的危险因素分析

目的:探索呼吸功能正常患者接受机械通气治疗发生急性呼吸窘迫综合征(ARDS)的危险因素。方法:回顾分析自2002年—2007年间接受通气治疗超过48h的患者资料,比较入住时呼吸功能正常患者是否发生ARDS之间的不同。结果:共有823例患者接受了超过48h的机械通气治疗。其中751例患者符合入选标准,接受机械通气治疗时临床上排除充血性心功能衰竭,明确无ARDS存在,但在随后的治疗期间139例最后发生ARDS。单因素回归分析表明高吸气峰压(相对危险度OR值1.70,可信区间CI1.41～2.07),PEEP(相对危险度OR值1.76,可信区间CI1.45～2.14)和潮气量(相对危险度OR值1.07,可信区间CI1.06～1.10)增加是显著危险因素。非机械通气相关的因素包括脓毒血症,低pH值,低白蛋白,血浆,高净液体输入和低呼吸顺应性。多元回归分析表明机械通气相关因素PEEP及潮气量影响ARDS。而峰气道压,平台压均与ARDS无关。结论:机械通气设置等因素潮气量及PEEP与ARDS密切相关。合理设置参数可以一定程度上预防部分患者发生ARDS。     

呼气末正压对中枢性呼吸衰竭患者中心静脉压和脉氧饱和度的影响

目的 评估呼气末正压(PEEP)对中枢性呼吸衰竭患者中心静脉压(CVP)和脉氧饱和度(SpO2)的影响.方法 30例神经外科ICU中枢性呼吸衰竭患者均予同步间隙指令通气(SIMV),在不同PEEP水平(0、3、6、9、12、15 cm H2O)记录分析所有患者CVP和SpO2的变化,研究不同PEEP水平对重症患者CVP的影响.结果 CVP随PEEP水平的增加而增高,PEEP与CVP呈直线正相关(r=0.463,P=0.000),一元线性回归方程为:CVP (cm H2O)＝7.865+0.359×PEEP(cm H2O).在不同PEEP水平时SpO2比较差异无统计学意义(P>0.05).结论 PEEP可以增加中枢性呼吸衰竭患者CVP,而对SpO2无明显影响.     

不同呼吸末正压对机械通气患者心脏前负荷影响及前负荷预测性指标研究

目的观察不同呼气末正压(PEEP)对机械通气(MV)危重患者血流动力学的影响及研究中心静脉压(CVP)、每搏输出量变异(SVV)及脉压变异(PPV)对PEEP介导的心脏前负荷变化的预测性。方法选择2006年7月～2007年7月重症加强治疗病房(ICU)的机械通气危重患者12例,采用容量控制通气,VT=10mL/kg,维持PaCO2=35～45mmHg,以随机的顺序调节4种PEEP水平,即PEEP为0mmHg(PEEP0),5mmHg(PEEP5),10mmHg(PEEP10),15mmHg(PEEP15),比较不同PEEP水平下血流动力学[心率(HR),平均动脉压(MAP),系统血管阻力指数(SVRI),心脏指数(CI),CVP,SVV,PPV]及呼吸机参数[气道峰压(Ppeak),气道平均压(Pmean)]的变化。结果PEEP0与PEEP5组间除Pmean外各指标均无明显差异,随PEEP的进行性升高,CI明显下降(P&;lt;0.05),HR、SVRI、Ppeak、Pmean升高,前负荷指标CVP、SVV、PPV亦显著性升高,MAP则无明显影响。以PEEP0为基线,PEEP10及PEEP15水平下心脏指数变化值(△...     

床旁胸片评价急性心肌梗死患者并发肺水肿

目的 观察床旁胸片中急性心肌梗死患者并发肺水肿的影像特点,评价其诊断价值.方法 回顾分析103例急性心肌梗死患者床旁胸片表现及临床资料.结果 34例(33%)有肺水肿影像表现,其中肺纹理模糊和肺门影增大、模糊34例(100%),间隔线11例(32.3%),支气管袖口征8例(23.5%),胸膜下水肿7例(20.6%),少量胸腔积液6例(17.6%).结论 床旁胸片是诊断肺水肿重要而有效的检查手段.肺纹理模糊和肺门影增大、模糊为肺水肿在床旁胸片中的重要征象.     

呼气末正压对血管外肺水及氧合的影响

目的 探讨不同水平的呼气末正压(PEEP)对接受机械通气的感染性休克患者血管外肺水指数(EVLWI)及氧合指数(PaO2/FiO2)的影响.方法 采用前瞻性、干预性的研究方法对北京协和医院MICU 15例行机械通气的感染性休克患者应用跨肺热稀释法及持续脉搏轮廓的方法进行血流动力学监测(PiCCO plus).所有患者采用容量控制通气,血流动力学稳定后,每隔1 h递增PEEP水平,PEEP从0增加到20 cm H2O(如果能耐受),根据不同的PEEP水平分为五组(0、5、10、15、20 cm H2O).应用one-way ANOVA和Pearson's进行统计分析及相关分析,观察不同水平的PEEP对EVLWI、PaO2/FiO2的影响及其相关性.结果 15例感染性休克患者,男10例(67%),女5例(33%),平均年龄(67.6 ± 19.5)岁,APACHEⅡ评分(22.1 ± 7.5)分,基础PEEP( 8.5 ± 3.6 )cm H2O, 基础PaO2/FiO2(225.6 ± 89.2)mm Hg,ICU病死率67.6%.随着PEEP的升高,PaO2/FiO2升高,各组间比较差异有统计学意义(P＜0.05),PEEP 对EVLWI及肺毛细血管通透性(PVPI)无明显影响.PaO2/FiO2与EVLWI、PVPI呈负相关(PaO2/FiO2 vs. EVLWI: r=-0.258,P=0.034;PaO2/FiO2 vs. PVPI: r=-0.324,P=0.007).结论 短时间应用PEEP 能改善氧合,但不降低 EVLWI.     

Respiratory variability of inferior vena cava at different mechanical ventilator settings

BackgroundAssessment of the respiratory changes of the inferior vena cava (IVC) diameter have been investigated as a reliable tool to estimate the volume status in mechanically ventilated and spontaneously breathing patients. Our purpose was to compare the echocardiographic measurements the IVC diameter, stroke volume and cardiac output in different positive pressure ventilation parameters.MethodsThis prospective clinical study with crossover design was conducted in the Intensive Care Unit (ICU). Twenty-five sedated, paralyzed, intubated, and mechanically ventilated patients with volume control mode (CMV) in the ICU due to respiratory failure were included in the study. Positive End-Expiratory Pressure (PEEP) and Tidal Volume (TV) were changed in each patient consecutively (Group A: TV 6 ml/kg, PEEP 5 cmH20, B: TV 6, PEEP 8, C: TV 8, PEEP 5, D: TV 8, PEEP 8) and the changes in vital parameters, central venous pressure (CVP) and ultrasonographic changes in IVC and cardiac parameters were measured. All measures were compared between groups by robust repeated measures ANOVA with trimmed mean.ResultsThe respiratory changes of the IVC diameter and echocardiographic parameters showed no significant difference in separate mechanical ventilator settings. Significant difference was found in peak and plateau pressure values among groups (p < 0.05).ConclusionThe results of our study suggest that IVC related parameters are not affected with different ventilatory settings. Further studies are needed to confirm the reliability of these parameters as a predictor of fluid assessment.     

Diagnostic accuracy of portable chest radiograph in mechanically ventilated patients when compared with autopsy findings

PurposeEvaluate diagnostic accuracy of portable chest radiograph in mechanically ventilated patients taking autopsy findings as the gold standard and the interobserver agreement among intensivists and radiologists.Materials and methodsRetrospective study of 422 patients over 22 years who died in the ICU, underwent an autopsy, and had at least one portable chest radiograph 72 h prior to death. Two intensivists and two radiologists independently read each chest radiograph. Sensitivity, specificity, positive and negative likelihood ratios were evaluated. Overall performance metrics accuracy between intensivists and radiologists were compared using a generalized estimating equation. Cohen's kappa coefficient was used to evaluate the interobserver agreement with the following values: <0.20:poor, 0.21–0.40:fair, 0.41–0.60:moderate, 0.61–0.80:good, 0.81–1.00:excellent.ResultsOverall sensitivity and specificity for pneumonia was 24% and 91% respectively. Overall sensitivity and specificity for ARDS was 68% and 74% respectively. Sensitivity for pneumonia was higher among radiologists (p < 0,05). Specificity for ADRS was higher among radiologists (p < 0,05). Good interobserver agreement among radiologists and poor correlation between intensivists was found.ConclusionsChest radiographs has a moderate specificity for ARDS and a high specificity for pneumonia, with limited sensitivity in both entities. Interobserver agreement of portable chest radiograph in the mechanically ventilated patients is higher between radiologists than intensivists.     

Efficacy of daily routine chest radiographs in intubated, mechanically ventilated patients

OBJECTIVE: To determine the efficacy of daily routine chest radiographs in intubated, mechanically ventilated patients. DESIGN: With approval of our Institutional Review Board, data were collected prospectively to compare bedside clinical assessment of the patient with the routine chest radiograph in determining the occurrence of new findings. Before review of the daily chest film, patients underwent careful evaluation of clinical and physiologic variables by critical care physicians, who then documented the new findings and the diagnostic and therapeutic interventions required. These results were compared with the interpretations of the daily chest film by radiologists blinded to the clinical assessment. Correlations were made of the new major (requiring immediate intervention) and new minor (abnormal but not requiring immediate intervention) findings noted by clinical assessment and chest radiography. SETTING: This study was conducted in a ten-bed medical/surgical ICU admitting 650 to 750 patients/yr, a majority of whom require intubation and mechanical ventilation. PATIENTS: Seventy-seven episodes of intubation and mechanical ventilation in 74 patients were evaluated. Only patients with translaryngeal intubation and a requirement for mechanical ventilation beyond 24 hrs were considered for inclusion in this study. Major admitting diagnoses included malignancy, aspiration pneumonia, sepsis, liver failure, chronic obstructive pulmonary disease, and adult respiratory distress syndrome. INTERVENTIONS: Specific interventions were not made by study design; instead, clinical practice with and without the routine chest radiograph was compared. MEASUREMENTS AND MAIN RESULTS: The measure of comparison between the chest radiograph and clinical assessment was the correlation between the two for a number of major and minor findings defined in advance. A total of 538 chest radiographs were examined; of these, 354 (65.8%) did not disclose either new major or new minor findings as defined. One hundred sixty-three radiographs disclosed only new minor findings, 40.5% of which were anticipated by bedside assessment. However, in 13 (17.6%, 95% confidence interval 9% to 26%) of our 74 patients, new major findings were discovered only by chest radiography. CONCLUSIONS: These data demonstrate that, while a large percentage of radiographs will not disclose new findings, routine daily studies have a substantial impact on the management of intubated, mechanically ventilated patients in the ICU. These findings support the use of daily chest radiographs in critically ill patients.     

Routine delirium monitoring is independently associated with a reduction of hospital mortality in critically ill surgical patients: A prospective,observational cohort study

PurposeAlthough delirium monitoring is recommended in international guidelines, there is lacking evidence for improved outcome due to it. We hypothesized that adherence to routine delirium monitoring would improve clinical outcome in adult critically ill patients.Material and methodsWe present the results of a prospective, noninterventional, observational cohort study that was conducted on 2 intensive care units (ICUs) of a tertiary care medical center between July and October 2007 (International Standard Registered Clinical Trial Record identifier: 76100795). We assessed delirium-monitoring and outcome parameters on a daily basis. Besides multivariate logistic and robust linear regression to analyze the relationship between delirium monitoring and outcome, we used the doubly robust augmented inverse probability weighting method for observational data to estimate effect sizes.ResultsOf 355 screened patients, we included 185 surgical ICU patients into our final analysis, of which 87 were mechanically ventilated. We found an independent association between delirium-monitoring adherence and in-hospital mortality for ventilated patients (odds ratio, 0.973; P= .041). Estimating the effect size, delirium monitoring indicated a reduction of 22% of in-hospital mortality if conducted 50% or more of ICU days per patient. The average ICU length of stay of 46 days was estimated to be reduced by 19 days (P= .031) if patients were sufficiently monitored.ConclusionOur data suggest an improved outcome for mechanically ventilated patients being screened for delirium in clinical routine.     

End-expiratory lung volume during mechanical ventilation: a comparison with reference values and the effect of positive end-expiratory pressure in intensive care unit patients with different lung conditions

Introduction

Functional residual capacity (FRC) reference values are obtained from spontaneous breathing patients, and are measured in the sitting or standing position. During mechanical ventilation FRC is determined by the level of positive end-expiratory pressure (PEEP), and it is therefore better to speak of end-expiratory lung volume. Application of higher levels of PEEP leads to increased end-expiratory lung volume as a result of recruitment or further distention of already ventilated alveoli. The aim of this study was to measure end-expiratory lung volume in mechanically ventilated intensive care unit (ICU) patients with different types of lung pathology at different PEEP levels, and to compare them with predicted sitting FRC values, arterial oxygenation, and compliance values.

Methods

End-expiratory lung volume measurements were performed at PEEP levels reduced sequentially (15, 10 and then 5 cmH₂O) in 45 mechanically ventilated patients divided into three groups according to pulmonary condition: normal lungs (group N), primary lung disorder (group P), and secondary lung disorder (group S).

Results

In all three groups, end-expiratory lung volume decreased significantly (P < 0.001) while PEEP decreased from 15 to 5 cmH₂O, whereas the ratio of arterial oxygen tension to inspired oxygen fraction did not change. At 5 cmH₂O PEEP, end-expiratory lung volume was 31, 20, and 17 ml/kg predicted body weight in groups N, P, and S, respectively. These measured values were only 66%, 42%, and 34% of the predicted sitting FRC. A correlation between change in end-expiratory lung volume and change in dynamic compliance was found in group S (P < 0.001; R ² = 0.52), but not in the other groups.

Conclusions

End-expiratory lung volume measured at 5 cmH₂O PEEP was markedly lower than predicted sitting FRC values in all groups. Only in patients with secondary lung disorders were PEEP-induced changes in end-expiratory lung volume the result of derecruitment. In combination with compliance, end-expiratory lung volume can provide additional information to optimize the ventilator settings.     

Arm position on portable neonatal/infant ICU chest radiograph can mimic lamellar effusion

Introduction/BackgroundArm malposition in neonatal ICU radiographs may result in overlap of the arm soft tissues and chest wall giving the appearance of lamellar effusions. We aimed to determine the frequency of arm malposition on portable neonatal/infant intensive care unit (N/IICU) chest radiographs and the proportion of these mimicking lamellar effusions.Material and MethodsWe evaluated a subgroup of supine portable chest radiographs performed at the N/IICU. Two reviewers, at a tertiary pediatric hospital located in the USA, evaluated each radiograph in consensus and classified arm position for either side independently as (1) acceptable: arm abducted and separated from the chest and (2) compromised: arm down and in contact with chest soft tissue. The compromised cases were evaluated regarding any overlap between soft tissues of the arm and chest of sufficient degree to mimic a lamellar effusion.ResultsWe reviewed 300 radiographs performed at the N/IICU (600 hemithoraces). The mean age was 1.8 ± 1.8 months. Of 600 hemithoraces, 233 (39%) showed arms down and in contact with the chest. In seven (1%) cases, the arm position was compromised and mimicked a lamellar effusion. We identified 32 (5%) true lamellar effusions in the whole sample; in 14 of the 32 cases with lamellar effusion, the radiographs were performed with the arms down.ConclusionPortable chest radiographs performed in the N/IICU without proper arm abduction represent a potential for misinterpretation of chest radiographs. Although the prevalence of mimickers of lamellar effusion is only around 1%, the prevalence of arms down on a portable chest radiograph is considerably high (39%).     

Ventilation Practices and Critical Events during Transport of Ventilated Patients outside of Hospital: A Retrospective Cohort Study

Introduction. Little is known about mechanical ventilation practices during patient transport outside of hospital in the civilian setting, although these practices may have clinical impact. Objective. We set out to describe ventilation practice, the use of lung-protective ventilation strategies, administration of sedation and neuromuscular blockade, and related critical events during out-of-hospital transport of ventilated patients. Methods. We conducted a population-based retrospective cohort study. Ventilator, pharmacy, and clinical data were extracted from the database of the provincial transport medicine agency in Ontario, Canada. Patients at risk for acute lung injury were identified by explicit screening criteria and lung-protective ventilation was assessed according to evidence-based thresholds. Critical events occurring during transport consisting of clinical deterioration or resuscitative procedures were recorded. Results. We identified 1,735 mechanically ventilated adults who received out-of-hospital transport. Volume control and pressure control were the most commonly used ventilation modes. The median tidal volume delivered during transport was 500 mL (interquartile range 450–600) with positive end-expiratory pressure (PEEP) of 5 cmH₂O (5–7) and peak inspiratory pressure of 24 cmH₂O (20–29). Most patients (92%) were ventilated with peak pressures ≤ 35 cmH₂O; 22% of patients were ventilated with PEEP < 5 cmH₂O. Ventilation in patients at risk of acute lung injury was not significantly different, and 68% of this subgroup was ventilated within lung-protective thresholds. Sedation was administered in 1,235 transports (71.2%) with frequent repeat administration. Neuromuscular blockade was administered in 385 transports (22.2%). Critical events occurred during 297 (17.1%) transports, due primarily to new-onset hypotension (n = 208). New in-transit hypotension was independently associated with sedative administration. Conclusions. In-transit mechanical ventilation practices are variable, although patient exposure to potentially injurious pressures and volumes is uncommon. The application of PEEP is modest. In-transit hypotension is common and associated with sedative administration. The extent to which these practices impact patient outcome is unclear.     

Transport of Mechanically Ventilated Patients in the Prone Position

Objective: We present seven cases of patients with severe respiratory failure refractory to conventional ventilation who were safely transported in the prone position. Methods: We describe all cases of patients transported by a regional critical care network in the prone position from January 2010-June 2015. All patients were mechanically ventilated for respiratory failure and transported by specialized nonphysician critical care teams. Utilizing direct medical oversight and real-time technical support from the clinical department, each patient underwent a thorough bedside evaluation, transport ventilator trial, and transfer to a transport stretcher either with the endotracheal tube secured by an anesthesia pillow or overhanging the stretcher. Results: Seven patients with acute respiratory distress syndrome were transported in the prone position. Four were female (57%), with a median weight of 78 kg (range 58-131) and median age of 53 years (range 37-78). Initial vital signs demonstrated a median oxygen saturation of 94% (range 90-97%) supported with a FiO₂ of 100% for all patients with a median positive end-expiratory pressure (PEEP) of 16 (range 14-20). Seven patients were transported, six by helicopter and one transported by ground ambulance. The median transport time was 36 minutes (IQR 19, 51). There were no deaths or major incidents (tube dislodgement or line displacement) during patient transport. Conclusion: The transport of mechanically ventilated patients with respiratory failure in the prone position is feasible and safe, with minimal complications identified in this case series.     

A computerized method to measure systolic pressure variation (SPV) in mechanically ventilated patients

Introduction.Intrathoracic pressure variation duringmechanical ventilation has different effects on cardiac preload andstroke volume in both ventricles. Changes in left ventricle strokevolume are reflected by fluctuations of the arterial pressure waveformor Systolic Pressure Variation (SPV). SPV has been proposed as a way toevaluate vascular volume status in mechanically ventilated patients aswell as responsiveness of the left ventricle stroke volume to volumeloading. Objective.In this paper an automated system ispresented which is designed in order to provide physicians withinformation on SPV in mechanically ventilated patients. Methods.The developed system acquires the pressure transducer signal andanalyses the pressure waveform in order to detect and identify thehemodynamic changes. Five patients underwent the clinical protocol inorder to evaluate the software reliability. Each patient underwentmeasurements with positive end-expiratory pressure (PEEP) equal to 0 cmH₂O, at an increase of 30% tidal volume, and at 15 cmH₂O of PEEP, before and after infusion of 7 ml/kg of colloidsolution. Results.The reliability of the automated procedure hasbeen verified by comparing the obtained results with data collectedmanually in order to test on whether the new method data are correlatedwith the conventional procedure. Our results show that in the worst casewhen the widest range for the limits of agreement is considered, theerror is within 15%. Conclusions.The automated SPVmeasurement requires less time as well as human errors compared to themanual method; this makes SPV calculation a competitive alternative tomethods for the measurements of stroke volume variations as arterialthermodilution technique and transesophageal echocardiography, whichrequire sophisticated equipment and specific experience.