感染性休克患者中心静脉血和混合静脉血氧饱和度缺乏一致性

目的感染性休克患者的中心静脉血氧饱和度(SCVO2)与混合静脉血氧饱和度(SVO2)的相关性分析。方法符合感染性休克诊断的25例患者分成重症肺炎组和腹腔感染组。所有患者均留置Swan-Ganz导管,从入科开始,每隔6小时不分顺序抽取中心静脉血和混合静脉血,进行血气分析,获取SCVO2和SVO2,对数据进行统计分析。结果所有患者及重症肺炎组、腹腔感染组的SCVO2和SVO2比较,差异均有统计学意义(t分别=4.90、4.29、7.21,P均<0.05),25例感染性休克患者SCVO2和SVO2的差异均值为(5.94±6.78)%,SCVO2比SVO2高,12例重症肺炎患者的SCVO2和SVO2的差异均值为(5.45±6.89)%,SCVO2比SVO2高,13例腹腔感染组患者的SCVO2和SVO2的差异均值为(7.90±6.22)%,SCVO2比SVO2高,重症肺炎组及腹腔感染组SCVO2和SVO2之间相关系数,差异有统计学意义(Δz=2.05,P<0.05)。结论感染性休克患者血流动力学不稳定时,尽量不用SCVO2替代SVO2。     

Effect of vasoactive treatment on the relationship between mixed venous and regional oxygen saturation

OBJECTIVE: To evaluate the relationship between the mixed venous (SvO2), hepatic, and femoral venous oxygen saturations before and during sympathomimetic drug infusions. DESIGN: Case series. SETTING: Tertiary care center. PATIENTS: Twenty-four ICU patients: postoperative open-heart surgery patients (n = 12), patients with septic shock (n = 8), and patients with acute respiratory failure (n = 4). INTERVENTIONS: In postoperative open-heart surgery patients and patients with respiratory failure, cardiac output was increased by at least 25% following therapy with either dobutamine or dopamine. Patients with septic shock were treated with either dopamine or norepinephrine to correct hypotension. MEASUREMENTS AND MAIN RESULTS: Vasoactive drug infusions increased cardiac index and oxygen delivery by 34% and oxygen consumption by 8%. SvO2 increased (62.6 +/- 6.7% vs. 69.5 +/- 6.0%, p less than .001). Although cardiac index was the most important determinant of SvO2, the correlation between cardiac index and SvO2 was weak (r2 = .32). The hepatic and femoral venous saturations also increased (49.0 +/- 12.1% vs. 59.4 +/- 9.8%, p less than .01, and 51.9 +/- 16.6% vs. 63.4 +/- 9.8%, p less than .001, respectively) in response to vasoactive treatment. The mean gradient between SvO2 and hepatic venous saturation was 11.9 +/- 8.7% and was independent of the clinical condition and baseline SvO2. The hepatic venous oxygen saturation increased in parallel with SvO2 regardless of the initial SvO2 value. CONCLUSIONS: The individual values of SvO2 have no predictive value concerning regional oxygen transport. The parallel increase in SvO2 and hepatic venous oxygen saturation suggests that the vasoactive treatment did not compromise splanchnic oxygenation.     

A reappraisal of isoproterenol in goal-directed therapy of septic shock

The goal of the study was to evaluate the effect of isoproterenol prescribed in goal-directed therapy for septic shock. Out of a cohort of 89 patients with septic shock, 14 patients treated with fluid and norepinephrine had inappropriate mixed venous oxygen saturation (SvO2<70%) not responding to correction of hypoxemia and anemia (>8 g.dL-1). Isoproterenol administration was started at a dose of 0.04 microg.kg-1.minute-1 with 0.025 microg.kg-1.minute-1 increments every 30 minutes until SvO2 was greater than 70%. Mean arterial pressure was maintained>or=65 mm.Hg by adjusting the norepinephrine infusion. Hemodynamic, oxygen, and renal variables were collected during a 12-h period. Patients with a known prior history of coronary disease were not eligible. Isoproterenol administration increased significantly SvO2 (62%+/-10% to 71%+/-9%), cardiac index (3.1+/-0.6 to 4.4+/-1.4 L.min-1.m-2), stroke index (27+/-3.4 to 38+/-6.1 mL.m-2), and left ventricular stroke work index (24+/-3.4 to 40+/-5.0 g.m-1.m-2). Heart rate rise did not reach a significant level. Arterial lactate concentration decreased significantly during the study period (5.7+/-2.8 to 3.4+/-1.6 mmol.L-1). No cardiac adverse events occurred with any electrocardiographic aspects of myocardial ischemia. This study suggests that isoproterenol is efficient to improve hemodynamics and oxygen variables in septic shock patients. There is a need for future investigations in larger groups of patients to determine whether isoproterenol can be an alternative to dobutamine.     

目标指导下治疗脓毒性休克的疗效观察

目的对比观察目标指导下脓毒性休克的治疗和传统经验治疗对息者预后的影响。方法采用随机、对照的方法对脓毒性休克患者进行目标指导下的治疗，目标：①中心静脉压（CVP）8～12mmHg（1mmHg=0．133kPa）；②平均动脉压（MAP）≥65mmHg；③上腔静脉血氧饱和度（SvO2）〉0．70；④尿量≥0．5ml／min。同时与经验性指导治疗的患者进行对比。观察两组患者人院后6、24和48hMAP、CVP、动脉血气分析、上腔静脉血气分析、静脉血乳酸含量、心脏每搏量、心排血指数、液体总量、血管活性药物总量、受损器官数目、呼吸机使用例数及7d和14d病死率。结果目标指导治疗组在较短时间内即可纠正休克和组织缺氧状态，24h和48h动脉血氧饱和度（SaO2）、SvO2、MAP、CVP较经验治疗组明显增高（P〈0．05或P〈0．01），乳酸含量降低（P〈0．01），经静脉输入的液体总量较多（P〈0．01），而血管活性药物应用较少（P〈0．01）；48hSaO2、SvO2、MAP、CVP的改善更加显著，受损器官数目少，程度较经验治疗组轻；7d及14d的病死率目标指导治疗组也较经验治疗组低（P〈0．05）。结论目标指导治疗脓毒性休克与经验治疗组相比可明显改善休克的预后。     

ACCM/PALS haemodynamic support guidelines for paediatric septic shock: an outcomes comparison with and without monitoring central venous oxygen saturation

INTRODUCTION: The ACCM/PALS guidelines address early correction of paediatric septic shock using conventional measures. In the evolution of these recommendations, indirect measures of the balance between systemic oxygen delivery and demands using central venous or superior vena cava oxygen saturation (ScvO(2) > or = 70%) in a goal-directed approach have been added. However, while these additional goal-directed endpoints are based on evidence-based adult studies, the extrapolation to the paediatric patient remains unvalidated. OBJECTIVE: The purpose of this study was to compare treatment according to ACCM/PALS guidelines, performed with and without ScvO(2) goal-directed therapy, on the morbidity and mortality rate of children with severe sepsis and septic shock. DESIGN, PARTICIPANTS AND INTERVENTIONS: Children and adolescents with severe sepsis or fluid-refractory septic shock were randomly assigned to ACCM/PALS with or without ScvO(2) goal-directed resuscitation. MEASUREMENTS: Twenty-eight-day mortality was the primary endpoint. RESULTS: Of the 102 enrolled patients, 51 received ACCM/PALS with ScvO(2) goal-directed therapy and 51 received ACCM/PALS without ScvO(2) goal-directed therapy. ScvO(2) goal-directed therapy resulted in less mortality (28-day mortality 11.8% vs. 39.2%, p=0.002), and fewer new organ dysfunctions (p=0.03). ScvO(2) goal-directed therapy resulted in more crystalloid (28 (20-40) vs. 5 (0-20 ml/kg, p<0.0001), blood transfusion (45.1% vs. 15.7%, p=0.002) and inotropic (29.4% vs. 7.8%, p=0.01) support in the first 6 h. CONCLUSIONS: This study supports the current ACCM/PALS guidelines. Goal-directed therapy using the endpoint of a ScvO(2)> or =70% has a significant and additive impact on the outcome of children and adolescents with septic shock.     

Comparison of systemic oxygen delivery and uptake with NIR spectroscopy of brain during normovolemic hemodilution in the rabbit.

Incremental hyperoxic normovolemic hemodilution was utilized to progressively decrease oxygen delivery (DO2) in anesthetized rabbits. At decreasing DO2, we compared systemic responses related to the adequacy of DO2, i.e. mixed venous oxygen saturation (SvO2), oxygen consumption (VO2), and arterial lactate concentrations, to near infrared spectroscopy (NIRS) of the brain, a regional measure of intracellular oxygen availability. We sought concomitantly to define critical SvO2 and DO2, beyond which whole body VO2 begins to decline and arterial lactate concentrations increase. NIR Spectroscopy provided the means to test the hypothesis that systemic indicators of inadequate DO2 would not accurately reflect the oxygenation of a critical organ such as the brain. In thirteen rabbits anesthetized with fentanyl, paralyzed and artificially ventilated at an FIO2 of 0.60, hemodilution produced an early decrease in mixed venous oxygen saturation. When mixed venous oxygen saturation decreased below approximately 50%, arterial lactate concentrations began to increase significantly. Further decreases in oxygen delivery precipitated a decline in systemic VO2. Finally, NIRS revealed an increase in the reduction level of brain cytochrome a,a3 after systemic parameters of oxygen delivery had been altered. Analysis of the data indicated that falling SvO2 predicted inadequate DO2 to tissue during early hemodilution under narcotic/relaxant anesthesia and that the brain showed evidence of intracellular hypoxia only after systemic parameters such as SvO2 were affected markedly.     

丙酮酸乙酯对脓毒性休克犬氧代谢及组织灌注指标的影响

目的 探讨丙酮酸乙酯(EP)对脓毒性休克犬组织氧合及灌注指标的影响.方法 健康雄性杂种犬20只,用脂多糖(LPS)静脉注射复制犬脓毒性休克模型,随机分为对照组(n=8)和EP组(n=12).对照组只接受林格液复苏;EP组除给予林格液复苏外加EP,首剂0.05 g/kg,然后以0.05 g·kg-1·h-1的量持续泵入.脓毒性休克模型稳定后记为0 h,此后12 h内每2 h收集组织氧合及灌注指标:氧输送(DO2)、氧消耗(VO2)、血乳酸(Lac)水平、混合静脉血氧饱和度(S vO2)、尿量、胃黏膜pH值(pHi)、胃-动脉二氧化碳分压差(Pg-aCO2).结果 脓毒性休克模型建立后,DO2、VO2、S vO2、尿量明显下降(P均＜0.05),Lac、Pg-aCO2明显上升(P均＜0.05).EP组DO2逐渐回升,8 h后与对照组比较差异仍有统计学意义(P＜0.05);VO2也有增加趋势,但与对照组比较差异无统计学意义(P＞0.05);S vO2逐渐上升,10 h后已显著超过制模前水平,且与对照组比较差异有统计学意义(P＜0.05);Lac水平逐渐下降,8 h后与对照组比较差异有统计学意义(P＜0.05);尿量在8 h后明显增加,10 h后与对照组比较差异有统计学意义(P＜0.05);pHi在6 h后明显上升,且与对照组比较差异有统计学意义(P＜0.05);Pg-aCO2在休克后8 h其升高程度较对照组低(P＜0.05).结论 EP可以改善脓毒性休克犬氧代谢及组织灌注.     

Increases in oxygen extraction during rapidly fatal septic shock in rats

Oxygen utilization was studied in a lethal model of rat peritonitis. Cecal ligation and perforation induced rapidly fatal septic shock in five animals. Five animals served as sham-operated controls. Arterial pressure, cardiac output, arterial blood lactate concentration, and arterial and central venous blood gases were sequentially measured over a period of 3 hours. In septic animals, systemic oxygen extraction increased from 33% +/- 5% to 70% +/- 5% (P less than 0.01) to maintain total body oxygen consumption. However, arterial lactate level increased from 0.5 +/- 0.1 mmol/L to 4.9 +/- 0.5 mmol/L (P less than 0.01) over the same study interval. Cardiac output was correlated with central venous oxygen desaturation (r = 0.66, P less than 0.001). Central venous oxygen saturation was inversely correlated with lactate concentration (r = -0.87, P less than 0.001). These data suggest that cellular oxygen utilization is largely maintained during rapidly fatal septic shock.     

Shock index: a re-evaluation in acute circulatory failure.

STUDY OBJECTIVE: To evaluate the relationship between the shock index SI (ratio of heart rate to systolic arterial pressure) and cardiac function and oxygen transport in an experimental model of hemorrhage and clinical septic shock. METHODS AND RESULTS: This study was conducted in a hypovolemic circulatory failure model; 40% hemorrhage in the anesthetized pig and normovolemic hyperdynamic septic patients in the intensive care unit (ICU). Hemodynamic and oxygen transport variables were measured and their relationships to SI was examined. SI was inversely related to blood loss, cardiac index (CI), stroke volume (SV), mean arterial pressure (MAP) and left ventricular stroke work (LVSW) (r = -0.73, -0.75, -0.89 and -0.75, respectively P less than 0.01) following hemorrhage in the anesthetized pig. Oxygen transport variables, i.e. oxygen delivery (DO2) and mixed venous oxygen saturation (SvO2P) (r = -0.68 and -0.74, respectively, P less than 0.01) were also inversely related to the SI. Oxygen consumption (VO2) increased initially with increasing SI and fell when SI was greater than 3.0. In clinical septic shock and following blood volume expansion, the SI was not correlated to CI, SVI, MAP or systemic vascular resistance (SVR) (r = -0.01, -0.47, -0.34 and -0.14, respectively, P-value NS) but was inversely related to LVSWI (r = -0.68, P less than 0.01). There were no relationships between the SI and oxygen transport variables (DO2, SvO2) (r = -0.02 and -0.17, P-value NS) in septic shock. CONCLUSION: SI provides a non-invasive means to monitor deterioration or recovery of LVSW during acute hypovolemic and normovolemic circulatory failure and its therapy. SI may be of limited value in the assessment of systemic oxygen transport and response to therapy in clinical shock.     

Bench-to-bedside review: The initial hemodynamic resuscitation of the septic patient according to Surviving Sepsis Campaign guidelines – does one size fit all?

The Surviving Sepsis Campaign guidelines for the management of severe sepsis and septic shock recommend that the initial hemodynamic resuscitation be done according to the protocol used by Rivers and colleagues in their well-known early goal-directed therapy (EGDT) study. However, it may well be that their patients were much sicker on admission than many other septic patients. Compared with other populations of septic patients, the patients of Rivers and colleagues had a higher incidence of severe comorbidities, a more severe hemodynamic status on admission (excessively low central venous oxygen saturation [ScvO2], low central venous pressure [CVP], and high lactate), and higher mortality rates. Therefore, it may well be that these patients arrived to the hospital in late untreated hypovolemic sepsis, which may have been due, in part at least, to low socioeconomic status and reduced access to health care. The EGDT protocol uses target values for CVP and ScvO2 to guide hemodynamic management. However, filling pressures do not reliably predict the response to fluid administration, while the ScvO2 of septic patients is characteristically high due to decreased oxygen extraction. For all these reasons, it seems that the hemodynamic component of the Surviving Sepsis Campaign guidelines cannot be applied to all septic patients, particularly those who develop sepsis during their hospital stay.     

多巴胺与去甲肾上腺素治疗感染性休克患者的临床疗效比较

目的比较多巴胺与去甲肾上腺素治疗感染性休克的临床疗效。方法将我院收治的86例感染性休克患者随机分为多巴胺治疗组(DA组)和去甲肾上腺素治疗组(NE组)各43例,观察两组患者治疗6h后的动脉血乳酸、平均动脉压(MAP)以及混合静脉血氧饱和度(SvO2)的变化情况。结果治疗后NE组患者的动脉血乳酸、MAP以及SvO2水平较DA组有显著改善,组间差异有统计学意义(P<0.05),NE组疗效优于DA组。结论去甲肾上腺素治疗感染性休克的临床疗效优于多巴胺。     

Continuous central venous oximetry monitoring

Traditionally, bedside evaluation of tissue oxygenation has been accomplished by assessing mixed venous oxygen saturation (SvO2) using a fiberoptic pulmonary artery catheter. It may not always be feasible to place a pulmonary artery catheter early in resuscitation or outside of the ICU. Introduction of continuous central venous oxygen saturation (ScvO2) monitoring that uses a modified, central venous catheter is making it possible to evaluate ongoing tissue oxygenation in nontraditional settings, such as the Emergency Department. Continuous measurement of ScvO2 will alert the clinician to major derangements in oxygen balance, which allows for timely implementation of appropriate interventions.     

Masseter muscle oxygen saturation is associated with central venous oxygen saturation in patients with severe sepsis

Objective  

This monocentric prospective study was conducted to determine if tissue oxygen saturation measured non invasively over masseter muscle site (Masseter-StO2) can predict the central venous oxygen saturation (ScvO2) level in severe sepsis and septic shock.     

Prevalence of low central venous oxygen saturation in the first hours of intensive care unit admission and associated mortality in septic shock patients: a prospective multicentre study

Introduction

In septic shock patients, the prevalence of low (<70%) central venous oxygen saturation (ScvO2) on admission to the intensive care unit (ICU) and its relationship to outcome are unknown. The objectives of the present study were to estimate the prevalence of low ScvO2 in the first hours of ICU admission and to assess its potential association with mortality in patients with severe sepsis or septic shock.

Methods

This was a prospective, multicentre, observational study conducted over a one-year period in ten French ICUs. Clinicians were asked to include patients with severe sepsis or septic shock preferably within 6 hours of ICU admission and as soon as possible without changing routine practice. ScvO2 was measured at inclusion and 6 hours later (H6), by blood sampling.

Results

We included 363 patients. Initial ScvO2 below 70% was present in 111 patients and the pooled estimate for its prevalence was 27% (95% Confidence interval (95%CI): 18% to 37%). At time of inclusion, among 166 patients with normal lactate concentration (≤2 mmol/L), 55 (33%) had a low initial ScvO2 (<70%), and among 136 patients who had already reached the classic clinical endpoints for mean arterial pressure (≥65 mmHg), central venous pressure (≥8 mmHg), and urine output (≥0.5 mL/Kg of body weight), 43 (32%) had a low initial ScvO2 (<70%). Among them, 49% had lactate below 2 mmol/L. The day-28 mortality was higher in case of low initial ScvO2 (37.8% versus 27.4%; P = 0.049). When adjusted for confounders including the Simplified Acute Physiology Score and initial lactate concentration, a low initial ScvO2 (Odds ratio (OR) = 3.60, 95%CI: 1.76 to 7.36; P = 0.0004) and a low ScvO2 at H6 (OR = 2.18, 95%CI: 1.12 to 4.26; P = 0.022) were associated with day-28 mortality by logistic regression.

Conclusions

Low ScvO2 was common in the first hours of admission to the ICU for severe sepsis or septic shock even when clinical resuscitation endpoints were achieved and even when arterial lactate was normal. A ScvO2 below 70% in the first hours of ICU admission and six hours later was associated with day-28 mortality.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-014-0609-7) contains supplementary material, which is available to authorized users.     

Towards a less invasive approach to the early goal-directed treatment of septic shock in the ED

Introduction

Early goal-directed therapy (EGDT) in septic shock defined by Rivers et al was proven to reduce mortality and validated by observational studies. However, criticism is centered in particular on the early requirement of a central venous catheter (CVC) and on central venous pressure (CVP) as an indicator of volume responsiveness. The present study is a pivotal study to investigate the reliability of a less invasive approach, which uses inferior vena cava (IVC) and lung ultrasounds (US) to guide the infusion of fluids and lactate clearance to monitor tissue perfusion.

Methods

We enrolled 51 patients with septic shock. As a marker of preload optimization, we measured IVC collapse in place of CVP and serum lactate clearance in place of central venous oxygen saturation as a marker of tissue perfusion. As outcomes, we considered the accomplishment of the noninvasive EGDT goals, the number of patients treated without the need of a CVC, the amount of fluids administered in the first 6 hours, the development of pulmonary edema, and the overall mortality rate.

Results

Inferior vena cava US evaluation resulted feasible in 92% of patients. Lung US was performed in 100% of cases. In the first 6 hours, only 61.7% of patients received a CVC, an average of 5.5 L of crystalloids were administered, and only 4 patients developed clinical overt pulmonary edema. Mortality was 34% at 28 days and 38.3% at 60 days.

Conclusions

Our approach to resuscitation in septic shock appears feasible in the emergency department and needs further study with a randomized controlled trial.     

Effect of blood transfusion on oxygen consumption in pediatric septic shock

Treatment plans for pediatric septic shock advocate increasing oxygen consumption (VO2). Recent studies in septic shock indicate that improving oxygen delivery (DO2) by increasing blood flow will increase VO2. We prospectively examined the effect on VO2 of improving DO2 by increasing oxygen content (CO2) with blood transfusion in eight hemodynamically stable septic shock patients. Transfusion consisted of 8 to 10 ml/kg of packed RBC over 1 to 2 h. Hemodynamic and oxygen transport measurements were obtained before and after blood transfusion. Transfusion significantly (p less than .05) increased Hgb and Hct from 10.2 +/- 0.8 g/dl and 30 +/- 2% to 13.2 +/- 1.4 g/dl and 39 +/- 4%, respectively (mean +/- SD). DO2 significantly (p less than .05) increased after transfusion (599 +/- 65 to 818 +/- 189 ml/min.m2), but VO2 did not change (166 +/- 68 to 176 +/- 74 ml/min.m2; NS). In pediatric septic shock patients, increasing CO2 by blood transfusion may not increase VO2.     

Central venous blood oxygen saturation and venous to arterial PCO2 difference after combined heart valve surgery

The aim of our study was to investigate the relationship between central venous oxygen saturation (ScvO2) and venous-to-arterial difference in PCO2 (Pv-aCO2) and their role in the assessment of balance between oxygen delivery and consumption after combined valve surgery. The prospective observation study included 38 adult patients with acquired valvular hear diseases, requiring surgical correction of two or more valves using cardiopulmonary bypass. All patients were divided into 2 groups according to the central value of central venous oxygen saturation (ScvO2): low ScvO2 (ScvO2 < 70%) and high ScvO2 (ScvO2 > 70%). In both groups blood gases, Pv-aCO2, lactate concentration, hemodynamic parameters, cardiac index, oxygen delivery and oxygen consumption were assessed. During the postoperative period there was a decrease of ScvO2 < 70% in 26% of patients which was accompanied by increased Pv-aCO2 > 5 mmHg and by risen oxygen consumption. We observed a moderate correlation between ScvO2 and Pv-aCO2 during the early postoperative period: at the end of surgery, 6 and 12 hours after it (rho = -0.53; -0.62 and -0.43 respectively, n = 38, p < 0.01). The changes in ScvO2 and Pv-aCO2 regressed after 24 hours in ICU. Thus, decreased ScvO2 and increased Pv-aCO2 after combined valve surgery are related and reflect the rise in oxygen consumption.     

Oxygen consumption monitoring by oxygen saturation measurements in mechanically ventilated premature neonates

PURPOSE: To assess oxygen consumption VO2) with arterial and venous oxygen saturation SaO2 and SvO2) from blood measurements for continuous monitoring of mechanically ventilated preterm neonates. METHOD: Twelve preterm neonates with gestational ages ranging from 27 to 34 weeks at birth, who were mechanically ventilated and had umbilical arterial and venous lines in place, were investigated. Analyses were performed with blood samples and continuous monitoring of VO2 from SaO2 and SvO2 measurements. RESULTS: Mean VO2 from blood samples was 3.3 mL/(kg min) (+/-2.49), and that from monitor readings was 8.8 (+/-4.49). Using curve fit analysis to predict the stability of monitor reading, the period from 8 to 28 hours following blood validation was most stable for SvO2 (cubic curve, R=0.5, P<.001). There is a considerable mix of arterial blood in the venous blood, which increased SvO2 and decreased VO2 in the blood samples during first 8 hours of monitoring following blood draws. A multivariate linear mixed model was established for VO2 measurements including related parameters. Ventilatory weaning was associated with decreased VO2. CONCLUSIONS: These findings warrant caution against interpreting VO2 from blood SvO2 and subsequent monitoring readings during mechanical ventilation for preterm neonates.