无创心排量联合中心静脉血氧饱和度监测对急性返流性胆管炎合并休克早期目标导向性液体复苏的指导作用

目的 探讨无创心排量（cardiac output,CO）联合中心静脉血氧饱和度（central venous oxygen saturation,ScvO₂）监测对急性返流性胆管炎合并休克早期目标导向性液体复苏的指导作用。方法 回顾性分析广州市花都区人民医院肝胆胰外科2015年1月至2019年12月间收治的94例急性返流性胆管炎合并休克患者资料,分为研究组和对照组两组,每组各47例。在指导早期液体复苏的治疗中,对照组监测患者平均动脉压（MAP）及中心静脉压（CVP）完成,研究组通过床旁多普勒无创血流动力学检测仪动态监测患者CO及经中心静脉导管监测患者ScvO₂。比较两组早期容量达标时间、24 h后休克指数变化、治疗后6 h血乳酸清除率,治疗前及治疗后第3、7天APACHE-III评分的变化情况,治疗后并发症发生率和病死率。结果 研究组早期容量达标时间较对照组明显缩短,24 h后休克指数较对照组明显降低,治疗后6 h血乳酸清除率明显高于对照组,且第3、7天的APACHE-III评分较对照组降低（均P＜0.05）;研究组治疗后并发的肝脓肿、肺部感染、急性肾功能衰竭及消化道出血发生率明显低于对照组（P＜0.01）,而脓毒血症发生率及病死率两组无明显差别（P＞0.05）。结论 临床上联合无创心排量和中心静脉血氧饱和度监测对急性返流性胆管炎合并休克患者早期液体管理具有良好指导作用,值得临床推广。     

Single transpulmonary thermodilution and continuous monitoring of central venous oxygen saturation during off-pump coronary surgery

Background: Off-pump coronary artery bypass grafting (OPCAB) requires thorough monitoring of hemodynamics and oxygen transport. Our aim was to find out whether therapeutic guidance during and after OPCAB, using an algorithm based on advanced monitoring, influences perioperative hemodynamic and fluid management as well as the length of post-operative ICU and hospital stay.
Methods: Patients were randomized into two groups of hemodynamic monitoring: the conventional monitoring (CM) group ( n =20) and the advanced monitoring (AM) group ( n =20). In the CM group, therapy was guided by central venous pressure, mean arterial pressure (MAP) and heart rate (HR), and in the AM group by the intrathoracic blood volume index, MAP, HR, central venous oxygen saturation (ScvO₂) and cardiac index (CI). The measurements were performed before and during surgery, and at 2, 4 and 6 h post-operatively.
Results: In the AM group, colloids and dobutamine were given more frequently and were accompanied by increments in ScvO₂, CI and oxygen delivery compared with baseline. The percentage of ephedrine administration was higher in the CM group. The algorithm guided by AM decreased time until achieving the status of 'fit for ICU discharge' and post-operative hospital stay by 15% and 25%, respectively.
Conclusions: A goal-directed algorithm based on advanced hemodynamic monitoring and continuous measurement of ScvO₂ facilitates early detection and correction of hemodynamic changes and influences the strategy for fluid therapy that can improve the course of post-operative period after coronary artery bypass grafting on the beating heart.     

Early goal-directed therapy in severe sepsis and septic shock: a contemporary review of the literature

PURPOSE OF REVIEW: Aggressive approaches to acute diseases such as acute myocardial infarction, trauma, and stroke have improved outcomes. Early goal-directed therapy for severe sepsis and septic shock represents a similar approach. An analysis of the literature assessing external validity and generalizability of this intervention is lacking. RECENT FINDINGS: Eleven peer-reviewed publications (1569 patients) and 28 abstracts (4429 patients) after the original early goal-directed therapy study were identified from academic, community and international settings. These publications total 5998 patients (3042 before and 2956 after early goal-directed therapy). The mean age, sex, APACHE II scores and mortality were similar across all studies. The mean relative and absolute risk reduction was 0.46 +/- 26% and 20.3 +/- 12.7%, respectively. These findings are superior to the original early goal-directed therapy trial which showed figures of 34% and 16%, respectively. A consistent and similar decrease in healthcare resource consumption was also found. SUMMARY: Early goal-directed therapy modulates systemic inflammation and results in significant reductions in morbidity, mortality, and healthcare resource consumption. Early goal-directed therapy has been externally validated and is generalizable across multiple healthcare settings. Because of these robust findings, further emphasis should be placed on overcoming logistical, institutional, and professional barriers to implementation which can save the life of one of every six patients presenting with severe sepsis and septic shock.     

A pilot study of continuous transtracheal mixed venous oxygen saturation monitoring

In this study, we investigated the feasibility and the accuracy of transtracheal mixed venous oxygen saturation (Svo(2)) monitoring. Ten patients undergoing thoracic surgery were included in this study. A single-use pediatric pulse oximetry sensor was attached to the double-lumen tube between the tracheal and bronchial cuff. After anesthesia was induced, the double-lumen tube was inserted into the trachea and adjusted to the proper position. During surgery, the pulmonary arterial blood was sampled every 3 min for 15 min to measure the Svo(2). The measurements made by the transtracheal pulmonary pulse oximeter (Sto(2)) were recorded at the same time that blood was sampled from the pulmonary artery for Svo(2) measurements. The levels of measurement agreement between the Sto(2) and the Svo(2) were analyzed using the Bland and Altman method. The mean +/- sd (range) oxygen saturation values during the data collecting period were 82.0% +/- 4.9% (72%-91%) for the Sto(2) and 82.2% +/- 5.5% (71%-91%) for the Svo(2), respectively. The linear correlation coefficient of the regression analysis between the Sto(2) and the Svo(2) was 0.934 (P < 0.05). A 95% confidence interval for absolute difference between the Sto(2) and the Svo(2) was 1.58%-2.09%. The mean +/- 2 sd difference between the Sto(2) and the Svo(2) was 0.12% +/- 3.97% on the Bland and Altman graph. We conclude that it is feasible to monitor the pulmonary artery oxygen saturation continuously by a transtracheal pulse oximetry technique and that it can be done so accurately. IMPLICATIONS: Mixed venous oxygen saturation (Svo2) is a measure of the balance between oxygen supply and consumption throughout the whole body. Svo2 can be measured invasively by inserting a pulmonary artery catheter with the associated disadvantages of cost and potential for patient injury. In this study, we investigated the feasibility of noninvasive Svo2 measurement using a transtracheal pulse oximetry technique.     

Clinical applicability of the substitution of mixed venous oxygen saturation with central venous oxygen saturation.

OBJECTIVE: To examine the clinical applicability of substituting central venous oxygen saturation (ScvO2) for mixed venous oxygen saturation (SmvO2) in monitoring global tissue oxygenation. DESIGN: Prospective clinical investigation. SETTING: University hospital. PARTICIPANTS: Seventy-three adult patients. INTERVENTIONS: Venous oxygen saturation was recorded, and oxygen saturation difference between SmvO2 and ScvO2 (DeltaSmvcv) was calculated in 2 groups of patients (group I, sepsis patients [n = 41], and group II, general anesthesia for cardiovascular surgery patients [n = 32]) during initial placement of pulmonary artery catheters. MEASUREMENTS AND MAIN RESULTS: Patients were classified as follows: class A, patients having a DeltaSmvcv >-5%; class B, patients having a DeltaSmvcv between -5% and +5%; and class C, patients having a DeltaSmvcv >+5 %. Statistically significant differences were observed in cardiac index, oxygen delivery index, and oxygen extraction ratio between class A and B in both groups. Class C of group II showed the worst correlation between SmvO2 and ScvO2 and had significantly lower arterial carbon dioxide tension values than class A and B. CONCLUSION: Pulmonary artery blood sampling should not be replaced with central venous blood. Hypocapnia and increased oxygen extraction ratio seem to be the major factors that worsen the relationship between ScvO2 and SmvO2.     

Central venous oxygen saturation for the diagnosis of low cardiac output in septic shock patients

Background: Simple diagnostic tests are needed to screen septic patients for low cardiac output because intervention is recommended in these patients. We assessed the diagnostic value of central venous oxygen saturation in the superior vena cava (ScvO₂) for detecting low cardiac output in patients with septic shock.
Methods: We conducted a prospective observational study in three general intensive care units (ICUs) of adult patients with septic shock, who were to have a catheter inserted for thermodilution measurement of cardiac index (CI_TD). Paired measurements of CI_TD and central venous oximetry values were obtained when the clinician first measured CI_TD.
Results: We included 56 patients with septic shock and a mean sequential organ failure assessment score of 12 (range 3–20). Baseline CI_TD was 3.5 l/min/m² (1.0–6.2) and ScvO₂ of 70% (33–87). The best cut-off of ScvO₂ for CI_TD>2.5 l/min/m² ( n =42) was a value ≥64% with positive and negative predictive values of 91% (95% confidence interval 79–98) and 91% (59–100), respectively. The diagnostic values were not improved by using instead central venous O₂ tension or the difference between arterial and central venous O₂ saturation.
Conclusions: This prospective, observational study found that a ScvO₂ measurement of ≥64% indicated CI_TD>2.5 l/min/m² in ICU patients with septic shock.     

Correlation between central venous oxygen saturation and oxygen delivery changes following fluid therapy

Background: The rationale for using central venous oxygen saturation (ScvO₂) in various clinical scenarios is that it reflects the balance between oxygen delivery (DO₂) and demands. In this study, we evaluated the correlation between ScvO₂ and DO₂ changes (ΔDo₂, ΔScvO₂) in patients receiving fluid therapy following coronary surgery. We also correlated the changes of mean arterial pressure (ΔMAP) and central venous pressure (ΔCVP), with ΔDO₂. Methods: Sixty consecutive sedated and mechanically ventilated adult patients, with cardiac index ≤2.3 L/min/m² and a pulmonary artery occlusion pressure ≤12 mmHg following coronary surgery, were included. Concomitant hemodynamic parameters, arterial and venous blood gases were measured before (T0) and after (T1) administration of a 500 ml bolus of an isotonic crystalloid solution over 30 min. The correlations between ΔDO₂ and ΔScvO₂, ΔMAP or ΔCVP were evaluated by linear regression analysis and Pearson test. Results: Cardiac index (1.9±0.2 vs 2.3±0.5 ml/min/m²), MAP (83±11 vs 94±13mmHg) and CVP (5.7±3 vs 7.1±3 mmHg) were significantly higher at T1 compared with T0. The correlation of ΔDO₂ with ΔScvO₂ was positive, significant (r=0.41; P=0.004) and superior to its correlation with ΔMAP (r=0.30; P=0.01) or ΔCVP (r=0.03; P=0.78). Conclusion: A significant correlation between ScvO₂ and DO₂ changes was found in patients receiving fluid therapy following coronary surgery. ScvO₂ could be used as an indicator to track DO₂ and to guide volume loading.     

Anesthetic experience for carotid endarterectomy in a patient with dilated cardiomyopathy under jugular venous oxygen saturation monitoring

A 73-year-old male with dilated cardiomyopathy was scheduled for carotid endarterectomy. General anesthesia was administered with intravenous propofol and fentanyl. Cardiac output and jugular venous oxygen saturations were continuously monitored during the operation to maintain adequate cerebral circulation. The jugular venous oxygen saturation was maintained at above 85% during the operation. The patient recovered smoothly without any neurological sequelae.     

Weaning from artificial respiration: value of continuous monitoring of mixed venous oxygen saturation

Weaning from mechanical ventilation is particularly difficult in patients with combined cardiac and respiratory failure. Continuous monitoring of mixed venous blood oxygen saturation (SvO2) redefines weaning in terms of tissue oxygenation. A stable SvO2 greater than 60% during weaning is a reliable index of weanability. However, further studies are required to establish a tolerance threshold for SvO2 during weaning. In the limited experience reported here, an immediate and abrupt fall in SvO2, when the patient started to breathe spontaneously was invariably associated with difficulties in weaning. In some patients, other signs of left ventricular dysfunction rapidly ensued, with a fall in cardiac index. Weaning remained possible if the treatment was capable of increasing cardiac output and normalizing SvO2. If, during spontaneous breathing, SvO2 remained stable in the 50-55% range, with no significant decrease in cardiac output, abrupt and unpredictable drops of SvO2 under 40% range occurred. Such falls always preceded signs of tissue hypoxia, leading to a resumption of controlled mechanical ventilation. However, further studies are required to fully delineate the role of SvO2 in the fine tuning of inotropic support and ventilatory assistance in the difficult weaning of patients recovering from cardio-respiratory failure.     

A maximal central venous oxygen saturation (SvO2max) for the surgical patient

Before induction of anaesthesia, 23 patients scheduled for major abdominal surgery had blood samples drawn from a central venous catheter for oxygen saturation (SvO₂) after graded infusion of isotonic saline. The infusion of saline was continued until further administration resulted in a stable SvO₂ (SvO₂max). The SvO₂ increased from 69 (53–83) to 72 (66–83) % (median and range; P < 0. 0001), when the patients received 10 (0–26) mL- kg^-1, average 500 mL, of saline. At the same time central venous haematocrit decreased from 38 (32–47) to 36 (23–47) % which suggests that the intravascular volume was expanded by 420 (180–3070) mL or by 72 (18–174) % of the administered volume. The results demonstrate that volume expansion by saline can establish a maximal venous oxygen saturation in the surgical patient.     

Successful treatment with continuous enteral protease inhibitor in a patient with severe septic shock

Objective

The mortality rate among patients with septic shock is high despite current therapy. We present a case of Fournier's gangrene and septic shock at 4 years post-heart transplantation that was reversed by “continuous enteral feeding” of the digestive enzyme inhibitor, gabexate mesilate. Recently, powerful pancreatic digestive proteases in the lumen of the intestine have been identified as initiators of the systemic inflammatory response. Intraluminal inhibitions of the proteases significantly attenuates intestinal damage, system inflammation, and multiorgan failure in experimental forms of shock but it has not been tested in man.

Methods and results

Gabexate mesilate, a synthetic digestive protease inhibitor, was continuously administered in two liters of crystalloid solution to a patient by enteral feeding during septic shock. The condition and markers for shock due to sepsis reversed in a few days.

Conclusion

This case suggested that “enteral” digestive protease inhibition may decrease and even reverse the sequelae of shock and sepsis.     

Trends but not individual values of central venous oxygen saturation agree with mixed venous oxygen saturation during varying hemodynamic conditions

BACKGROUND: Previous studies found contradictory results regarding the question whether mixed venous oxygen saturation (Svo2) and central venous oxygen saturation (Scvo2) are equivalent. The inconsistency of study results may result from different study designs and different, partly questionable, statistical approaches. METHODS: The authors performed a prospective clinical trial comparing individual oxygen saturation values as well as the trend of values in blood from the superior vena cava (Scvo2), the right atrium (Srao2), and the pulmonary artery (Svo2) during varying hemodynamic situations. The subjects were 70 patients scheduled to undergo elective neurosurgical operations in the sitting position. Oxygen saturation was measured photospectrometrically in blood samples simultaneously taken at four different time points during supine and sitting positions. Statistical analysis was performed following the recommendations of Bland and Altman. RESULTS: Five hundred two comparative sets of measurements were obtained. Ninety-five percent limits of agreement ranging from +/-6.83 to +/-9.30% for single values were interpreted as clinically unacceptable. In contrast, correlations between changes of Svo2 and Scvo2 as well as of Svo2 and Srao2 were interpreted as clinically acceptable (R > or = 0.755, Pearson correlation coefficient; P < or = 0.0001). CONCLUSIONS: In this sample of patients, exact numerical values of Scvo2 and Srao2 are not equivalent to those of Svo2 in varying hemodynamic conditions. However, for clinical purposes, the trend of Scvo2 may be substituted for the trend of Svo2. In addition, previous studies investigating the agreement between Svo2 and Scvo2 were found to be lacking in their chosen statistical approaches.