Central Venous Saturation Research Articles

The Prognostic Value of Central Venous-to-Arterial CO2 Difference/Arterial-Central Venous O2 Difference Ratio in Septic Shock Patients with Central Venous O2 Saturation ≥80%

It is a great challenge for physician to assess the relationship between O2 delivery and O2 consumption in septic shock patients with high ScvO2. Recently, the venous-to-arterial CO2 difference/arterial-central venous O2 difference ratio (P(v-a)CO2/C(a-v)O2) has shown potential for reflecting anaerobic metabolism. Therefore, we evaluated the value of using the P(v-a)CO2/C(a-v)O2 ratio to predict mortality and assess anaerobic metabolism in septic shock patients with high ScvO2 (≥ 80%). This was a clinical investigation of septic shock patients on the P(v-a)CO2/C(a-v)O2 ratio in the intensive care unit (ICU) department. The patients' arterial and central venous blood gas levels were measured simultaneously at enrollment (T0) and 24 h (T24) after resuscitation. A total of 61 patients with high ScvO2 at T24 after resuscitation were selected for analysis. The ICU mortality rate in the septic shock patients was 20% (12/61). The nonsurvivors had a significantly higher P(v-a)CO2, P(v-a)CO2/C(a-v) O2 ratio, arterial lactate level and lower lactate clearance at T24 after resuscitation. The P(v-a)CO2/C(a-v)O2 ratio had the biggest the areas under the receiver operating characteristic (AUC) for predicting ICU mortality. For predicting ICU mortality, a threshold of P(v-a)CO2/C(a-v)O2 ratio ≥1.6 was associated with a sensitivity of 83% and a specificity of 63%. Multivariate analysis showed P(v-a)CO2/C(a-v)O2 ratio at both T0 (RR 5.597, P = 0.024) and T24 (RR 5.812, P = 0.031) was an independent predictor of ICU mortality. Including the ratio into the regression model showed a bigger AUC than without the ratio (0.886 vs. 0.833). The P(v-a)CO2/C(a-v)O2 ratio is an independent predictor of ICU mortality in septic shock patients with high ScvO2 after resuscitation. It is worthy of consideration to recruit microcirculation to correct the high ratio in high ScvO2 case.

Measurement of Oxygen Consumption Variations in Critically Ill Burns Patients: Are the Fick Method and Indirect Calorimetry Interchangeable?

To evaluate the interchangeability of oxygen consumption variations measured with the Fick equation (ΔVO2Fick) and indirect calorimetry (ΔVO2Haldane) in critically ill burns patients. Prospective observational single-center study conducted in a university hospital. Twenty-two consecutive burns patients with circulatory insufficiency and hyperlactatemia (>2 mmol/L) who required a fluid challenge (FC) were included. All patients had cardiac output monitoring (transpulmonary thermodilution technique) and were ventilated and sedated. Simultaneous measurements of VO2Fick and VO2Haldane were performed before and immediately after the FC, at rest, and in hemodynamic conditions stabilized for at least 1 h. VO2Fick and VO2Haldane were measured, respectively, with the standard formulae (using arterial and central venous saturation measured with a blood gas analyzer) and with a metabolic monitor. Forty-four paired measurements of VO2 were obtained. At each timepoint, the median (interquartile range, 25-75) VO2Haldane values were significantly higher than the median VO2Fick values (126 (103-192) vs. 90 (66-149) mL O2/min/m (P = 0.004) before FC and 129 (105-189) vs. 80 (54-119) mL O2/min/m (P = 0.001) after FC). Correlation between the ΔVO2Fick and the ΔVO2Haldane (%) measurements was poor, with an r = 0.06, (P = 0.77). The mean bias was 8.6% [limits of agreement (LOA): -75.7%, 92.9%]. Analysis of agreement showed poor concordance for the ΔVO2Haldane and the ΔVO2Fick (%) with a low mean bias but large and clinically unacceptable LOA. ΔVO2Haldane and ΔVO2Fick (%) are not interchangeable in these conditions.

Comparison of the effects of phenylephrine and norepinephrine in patients with restrictive transfusion

Objective To compare the effects of phenylephrine and norepinephrine in patients with restrictive transfusion. Methods 65 patients undergoing laparoscopic resection of rectal cancer were selected.According to the random number table method, the patients were randomly divided into 32 cases of observation group(phenylephrine composite restriction infusion) and 33 cases of control group(norepinephrine combined restrictive transfusion). The operation and hemodynamics of the two groups at different time points were compared.At T0, T1, T2, the central venous blood and arterial blood were collected, the central venous blood saturation(ScvO2), arterial blood lactate(Lac), central venous oxygen partial pressure(PcvO2), PaO2, Hb concentrations, venous oxygen content(CcvO2), arterial oxygen content(CaO2), arteriovenous oxygen content difference(Ca-cvO2) and oxygen uptake rate(ERO2) were compared between the two groups. Results The ASA levels(Ⅰ/Ⅱgrade) of the observation group and the control group were 11 cases/21 cases and 13 cases/20 cases, respectively, the difference was not statistically significant(χ2=5.298, P=0.052). The BMI of the observation group and the control group were (20.61±1.65)kg/m2, (21.57±1.42)kg/m2, respectively, the difference was not statistically significant(t=0.652, P=1.980). The fluid replacement of the observation group and the control group were (1 162±113)mL, (1171±104)mL, respectively, the difference was not statistically significant(t=1.734, P=0.065). The blood loss of the observation group and the control group were (276±41)mL, (294±42)mL, respectively, the difference was not statistically significant(t=0.083, P=1.023). The urine volume of the observation group and the control group were (524±113)mL, (532±109)mL, respectively, the difference was not statistically significant(t=1.834, P=0.053). The operation time of the observation group and the control group were (192±24)min, (197±21)min, respectively, the difference was not statistically significant(t=1.367, P=0.073). The MAP at T1-T2 of the two groups increased, the CVP of the two groups was significantly higher at T1, the HR of the two groups was significantly higher at T2.The MAP, CVP, HR between the two groups had no significant differences(all P>0.05). The levels of ScvO2, PcvO2 and PaO2 at T1 were significantly higher than those at T0, on the contrary, the levels of ScvO2, PcvO2 and PaO2 at T2 were significantly lower than those at T0, and the Hb in the observation group was significantly lower at T1-T2, the Hb in the control group was significantly lower at T1-T2, which in the observation group was lower than the control group, the differences were statistically significant(all P 0.05). There were statistically significant differences in CcvO2, CaO2, Ca-cvO2 and ERO2 between the two groups at different time points(all P<0.05). Conclusion Phenylephrine is more effective than norepinephrine in limiting infusion in elderly patients, and it has more obvious effects on tissue oxygen metabolism. Key words: Infusions, intravenous; Norepinephrine; Deoxyepinephrine

Incidence and echocardiographic predictors of early postoperative right ventricular dysfunction following left ventricular assist implantation in paediatric patients.

Left ventricular assist device implantation is an established therapy for paediatric patients with end-stage heart failure. Early right ventricular dysfunction (RVD) after implantation still remains a challenge in the postoperative period. This study sought to determine the incidence of RVD and to identify echocardiographic predictors of RVD in paediatric patients, as well describing associated clinical outcome. Prospectively collected preoperative echocardiographic, haemodynamic, demographic and biochemical data from 48 patients scheduled for left ventricular assist device implantation were evaluated. Incidence of high central venous pressure, decreased central venous saturation, high inotropic support requirements or need for mechanical support of the right ventricle during the first 48 h after implantation were used to define RVD. Echocardiographic assessments of right ventricular geometry, function using linear dimensions, areas and tricuspid annular plane systolic excursion (TAPSE) were performed preoperatively and the relative relationships between these parameters were evaluated. We included 48 consecutive paediatric patients (median age 5 years, range 0-17; median weight 15.9 kg, range 3.6-91). According to our criteria, 24 (50%) patients developed RVD. TAPSE as the parameter for assessment of longitudinal systolic function was significantly lower in this group (P = 0.01). The difference became even more pronounced after normalization to the RV end-diastolic diameter in long axis with P = 0.003. The odds ratio for patients with TAPSE/RV end-diastolic diameter in long axis <17.1% to develop RVD was 7.7 (P = 0.002). RVD occurs frequently in paediatric patients after left ventricular assist device. TAPSE, normalized to the RV end-diastolic diameter, may help to identify patients at risk for RVD. The predictive value of this parameter supports decision making to plan for adequate pharmacological support or consider early upgrading to mechanical RV support.

Effects of different early infusion rate on hemodynamics of patients undergoing non-stop coronary artery bypass grafts

Objective To investigate the effects of different infusion rate of early infusion on the hemodynamics of patients undergoing coronary artery bypass grafting. Methods Forty-six patients with coronary artery disease who underwent coronary artery bypass surgery were randomly divided into two groups: observation group and control group. After the conventional anesthesia was stable, the patients in the control group were given continuous infusion of 2-3 ml/(kg·h) of normal saline. The patients in the observation group were successfully dissociated 5-7 ml/(kg·h) of liquid infusion before the internal mammary artery was successfully dissociated, then 2-3 ml/(kg·h) speed of liquid infusion was given. Results There was no significant difference in clinical data between the two groups. The hemodynamic parameters such as mean arterial pressure (MAP), heart rate (HR), cardiac output (CO), stroke volume variation (SVV) and central venous pressure (CVP) in the observation group were significantly better than those in the control group during the operation. The total dose of noradrenaline (NE) and adrenaline (E) in the observation group was significantly lower than that in the control group (t=3.908, 7.452, P=0.043, 0.002). The levels of venous blood oxygen partial pressure (PvO2) and continuous central venous saturation (ScvO2) in the observation group were significantly higher than those in the control group (t=4.099, 3.679, 4.208, 2.214, P=0.046, 0.037, 0.032, 0.049), and the lactic acid level and oxygen uptake rate were significantly lower in the observation group than in the control group. The peak values of lactate and creatinine in the observation group were significantly lower than those in the control group (t=3.709, 2.311, P=0.038, 0.048). The levels of 24-h BNP in the control group were significantly higher than those in the observation group (t=4.911, P=0.041). The level of cTnⅠ in the observation group was significantly lower than that in the free internal mammary artery at 24 h after operation (t=7.224, P=0.011), but no significant difference was found in the control group at 24 h after operation (t=1.097, P=0.087). Conclusion The early and appropriate addition of salt solution, and limiting the amount of fluid during the bypass surgery in non-stop coronary artery bypass surgery can effectively stabilize the hemodynamic state, improve the state of oxygenation and reduce myocardial injury. Key words: Non-stop coronary artery bypass surgery; Restrictive infusion; Tissue oxygenation

WITHDRAWN: Pulse-induced contour cardiac output (PiCCO) combined with passive leg raising test predicting fluid resuscitation in adult patients with septic shock

To investigate the clinical value of pulse-induced contour cardiac output (PiCCO) monitoring combined with passive leg raising (PLR) test in predicting fluid responsiveness so as to guide fluid resuscitation in adult septic shock patients managed by rehydration test. One hundred and forty five adult septic shock patients, who were informed to receive PLR tests and rehydration tests. Patients were divided into two groups based on the observation of fluid responsiveness in the rehydration test. Parameters including heart rate (HR), central venous pressure (CVP), systolic blood pressure (SAP), mean arterial pressure (MAP), pulse pressure (PP), pulse indicates cardiac index (PCCI), central venous blood saturation in oxygen (ScvO2) and stroke fluid (SV) were monitored. By PLR test, CVP, SAP, MAP, PP, PCCI and ScvO2 were all increased significantly in the responding group; CVP, SAP, MAP, PP, PCCI and ScvO2 were all upregulated in the responding and nonresponding groups after PLR test (all P < 0.05). By rehydration test, CVP, MAP, PCCI, ScvO2 and SV were elevated in the responding group; and CVP, MAP and PCCI improved significantly both in both groups after rehydration test (all P < 0.05). PLR-ΔSV and PLR-ΔPP (PLR induced changes in stroke fluid) were both positively correlated with ΔSV (the rate of change of stroke fluid induced by fluid infusion test) (both P < 0.05). PLR combined with PiCCO may predict the fluid responsiveness in adult patients with septic shock by monitoring PLR-ΔSV associated with PLR-ΔPP, thereby contribute effectively to the guidance of fluid resuscitation.

Low values of central venous oxygen saturation (ScvO2) during surgery and anastomotic leak of abdominal trauma patients

BackgroundThere is a well known relationship between hypoperfusion and postoperative complications like anastomotic leak. No studies have been done addressing this relationship in the context of abdominal trauma surgery. Central venous oxygen saturation is an important hypoperfusion marker of potential use in abdominal trauma surgery for identifying the risk of anastomotic leak development. The purpose of this study was to identify the relationship between low values of central venous oxygen saturation and anastomotic leak of gastrointestinal sutures in the postoperative period in abdominal trauma surgery.MethodsA cross-sectional prospective study was performed. Patients over 14 years old who required surgical gastrointestinal repair secondary to abdominal trauma were included. Anastomotic leak diagnosis was confirmed through clinical manifestations and diagnostic images or secondary surgery when needed. Central venous oxygen blood saturation was measured at the beginning of surgery through a central catheter. Demographic data, trauma mechanism, anatomic site of trauma, hemoglobin levels, abdominal trauma index, and comorbidities were assessed as secondary variables.ResultsPatients who developed anastomotic leak showed lower mean central venous oxygen saturation levels (60.0% ± 2.94%) than those who did not (69.89% ± 7.21%) (p = 0.010).ConclusionsCentral venous oxygen saturation <65% was associated with the development of gastrointestinal leak during postoperative time of patients who underwent surgery secondary to abdominal trauma.

Direct Measurement of Tissue Oxygenation in Neonates via Resonance Raman Spectroscopy: A Pilot Study

Background: The ability to monitor tissue oxygenation in neonates remains a challenge due to limited blood supply and the reliance on invasive procedures. Resonance Raman spectroscopy noninvasively measures tissue oxygenation (RRS-StO₂). Peripheral tissue oxygenation using this novel technology has not been described in neonates. Objectives: To examine the relationship between short-term RRS-StO₂ measurements and central venous saturation (ScvO₂) and pulse oximetry (SpO₂) in preterm and term neonates. Methods: Ninety-seven term neonates had buccal and plantar RRS-StO₂ measurements performed. In 15 preterm neonates, similar measurements were obtained in conjunction with ScvO₂ in the first week of life. Simultaneous SpO₂ and heart rate were also recorded. Results: In healthy neonates, buccal RRS-StO₂ values negatively correlated with the day of life. No correlation existed between buccal and plantar RRS-StO₂ values and ScvO₂ or SpO₂. Greater intra-patient plantar RRS-StO₂ variability was seen in preterm neonates with increasing respiratory support. Conclusions: Neonatal RRS-StO₂ measurements are feasible short term but do not correlate with ScvO₂ and SpO₂. Healthy neonates had greater differences and variability in RRS-StO₂ values, illustrating an evolving microcirculation not detected with pulse oximetry. Greater RRS-StO₂ variability in sick neonates requiring respiratory support may indicate microcirculatory instability despite being within target SpO₂ ranges. Further study is needed to establish if RRS-StO₂ monitoring is an accurate representation of tissue oxygenation.

A validation method for near-infrared spectroscopy based tissue oximeters for cerebral and somatic tissue oxygen saturation measurements

We describe the validation methodology for the NIRS based FORE-SIGHT ELITE® (CAS Medical Systems, Inc., Branford, CT, USA) tissue oximeter for cerebral and somatic tissue oxygen saturation (StO2) measurements for adult subjects submitted to the United States Food and Drug Administration (FDA) to obtain clearance for clinical use. This validation methodology evolved from a history of NIRS validations in the literature and FDA recommended use of Deming regression and bootstrapping statistical validation methods. For cerebral validation, forehead cerebral StO2 measurements were compared to a weighted 70:30 reference (REF CXB) of co-oximeter internal jugular venous and arterial blood saturation of healthy adult subjects during a controlled hypoxia sequence, with a sensor placed on the forehead. For somatic validation, somatic StO2 measurements were compared to a weighted 70:30 reference (REF CXS) of co-oximetry central venous and arterial saturation values following a similar protocol, with sensors place on the flank, quadriceps muscle, and calf muscle. With informed consent, 25 subjects successfully completed the cerebral validation study. The bias and precision (1 SD) of cerebral StO2 compared to REF CXB was −0.14 ± 3.07%. With informed consent, 24 subjects successfully completed the somatic validation study. The bias and precision of somatic StO2 compared to REF CXS was 0.04 ± 4.22% from the average of flank, quadriceps, and calf StO2 measurements to best represent the global whole body REF CXS. The NIRS validation methods presented potentially provide a reliable means to test NIRS monitors and qualify them for clinical use.

Effects of blood transfusion on oxygen extraction ratio and central venous saturation in children after cardiac surgery.

BACKGROUNDRed blood cell transfusion is common in critically ill children after cardiac surgery. Since the threshold for hemoglobin (Hb) transfusion need is not well defined, the threshold Hb level at which dependent critical oxygen uptake-to-delivery (VO2-DO2) status compensation is uncertain.OBJECTIVESTo assess the effects of blood transfusion on the oxygen extraction ratio (O2ER) and central venous oxygen saturation (ScvO2) to identify a critical O2ER value that could help us determine the critical need for blood transfusion.DESIGNProspective, observational cohort study.SETTINGCardiac Surgical Intensive Care Unit at Prince Sultan Cardiac Center in Qassim, Saudi Arabia.PATIENTS AND METHODSBetween January 2013 and December 2015, we included all children with cardiac disease who underwent surgery and needed a blood transfusion. Demographic and laboratory data with physiological parameters before and 1 and 6 hours after transfusion were recorded and O2ER before and 6 hours after transfusion was computed. Cases were divided into two groups based on O2ER: Patients with increased O2ER (O2ER >40%) and normal patients without increased O2ER (O2ER ≤40%) before transfusion.MAIN OUTCOME MEASURE(S)Changes in O2ER and ScvO2 following blood transfusion.RESULTSOf 103 patients who had blood transfusion, 75 cases had normal O2ER before transfusion while 28 cases had increased O2ER before transfusion. Following blood transfusion, O2ER and ScvO2 improved in the group that had increased O2ER before transfusion, but not in the group that had normal O2ER before transfusion.CONCLUSIONSThe clinical and hemodynamic indicators O2ER and ScvO2 may be considered as markers that can indicate a need for blood transfusion.LIMITATIONSThe limitation of this study is the small number of patients that had increased O2ER before transfusion. There were few available variables to assess oxygen consumption.

Can the cerebral regional oxygen saturation be a perfusion parameter in shock?

IntroductionShock, defined as a state of tissue hypoperfusion and the tissues reperfusion, is the main goal of management of shock. Increase in central venous saturation (CvSo2) and decrease in blood lactate level are useful in assessment of adequacy of tissue perfusion. Near-infrared spectroscopy is a noninvasive way to observe real-time changes in regional cerebral saturation and has been used in patients with different brain diseases. There is a small body of literature suggesting that cerebral regional oxygen saturation (CrSo2) monitoring added a value in assessment and management of intensive care unit (ICU) patients. ObjectivesThe aim of this study was to determine if CrSo2 can be used as an indicator of tissue perfusion in ICU patients with shock, and to determine the prognostic value of CrSo2 in survival prediction. MethodsThis is a prospective single-center pilot study entailed 20 patients who were diagnosed with shock admitted to adult ICU at King Fahd Military Medical Complex, Dhahran, Saudi Arabia. The CrSo2 was monitored with near-infrared spectroscopy using Somatic, INVOS Oximeter 5100C (Covidien, Mansfield, Mass) with bilateral frontal electrode and mean value of the 2 readings was taken as well as blood lactate level, CvSo2, mean arterial blood pressure, and cardiac index at baseline time, 8, 24, 48, and 72 hours. All patients with history of cerebrovascular diseases and those who presented with neurological deficits were excluded from the study. ResultsSignificant negative correlation was noticed between CrSo2 and lactic acid at 8, 24, 48, and 72 hours from admission (r=−0.625, −0.711, −0.745, and −0.722, respectively; P=.003, .001, .001, and .001, respectively). Significant positive correlation was noticed between CrSo2 and CvSo2 at 8, 24, 48, and 72 hours from admission (r=0.572, 0.674, 0.527, and 0.757; P=.008, .001, .017, and .001, respectively). In addition, significant positive correlation was found between CrSo2 and mean arterial pressure at 24, 48, and 72 hours from admission (r=0.523, 0.513, and 0.626, respectively; P=.018, .021, and .003, respectively). Significant difference was also detected between the value of CrSo2 in the survivors (12 patients) and the nonsurvivors (8 patients) after 72 hours from admission, as it was 52.58%±7.33% and 44.75%±9.44% (P=.049), whereas it was not significantly different in the first 3 days. ConclusionsCerebral regional oxygen saturation might be helpful as one of the perfusion parameters in patients with shock and it could have a prognostic value in mortality prediction. However, further studies with larger sample size are still needed to validate these results.

Evaluation of Serum Lactate, Central Venous Saturation, and Venous-Arterial Carbon Dioxide Difference in the Prediction of Mortality in Postcardiac Arrest Syndrome.

Tissue hypoperfusion and hypoxia markers predict mortality in critically ill patients. This study evaluates the ability of serum lactate, central venous oxygen saturation (Scvo 2), and venous-arterial carbon dioxide difference (GapCo 2) to predict mortality in patients with postcardiac arrest (post-CA) syndrome. A prospective observational study of patients with post-CA in a tertiary teaching hospital. Serial assessments of lactate, lactate clearance (Clac), GapCo 2, and Scvo 2 in the first 72 hours post-CA were analyzed. Adults (≥18 years) patients resuscitated from CA were included. The primary end point was 28-day mortality and secondary end points were 24- and 72-hour mortality. A total of 54 patients were recruited, 33 (61,1%) of 54 were men, with a 28-day mortality of 75.9%. Cardiac arrest occurred in-hospital in 84.6% of survivors and 97.5% of nonsurvivors. Lactate and Clac were significantly associated with mortality at 28 days, yielding an area under the receiver-operating characteristic curve of 0.797 (lactate 6 hours) and 0.717 (Clac 6 hours) with a positive predictive value of 96% for lactate 6 hours (> 2.5 mmol/L) and 89.5% for Clac 6 hours (<50%). Survival analysis confirmed the difference between the groups from the 24th hour post-CA. Considering mortality at 24 hours, lactate, Clac, and Scvo 2 (immediately post-CA, 6 and 18 hours) were different between the groups. In mortality at 72 hours, lactate, Clac, Scvo 2 (48 hours), and GapCo 2 (36 and 48 hours) were associated with mortality. In post-CA syndrome, serum lactate and Clac were consistently able to predict mortality.

Association of haemodynamic changes measured by serial central venous saturation during ultrafiltration for acutely decompensated heart failure with diuretic resistance and change in renal function

BackgroundPatients with acute decompensated heart failure with diuretic resistance (ADHF-DR) have a poor prognosis. The aim of this study was to assess in patients with ADHF-DR, whether haemodynamic changes during ultrafiltration (UF) are associated with changes in renal function (Δcreatinine) and whether Δcreatinine post UF is associated with mortality. MethodsSeventeen patients with ADHF-DR underwent 20 treatments with UF. Serial bloods (4–6 hourly) from the onset of UF treatment were measured for renal function, electrolytes and central venous saturation (CVO2). Univariate and multivariate analysis were performed to assess the relationship between changes in markers of haemodynamics [heart rate (HR), systolic blood pressure (SBP), packed cell volume (PCV) and CVO2] and Δcreatinine. Patients were followed up and mortality recorded. Cox-regression survival analysis was performed to determine covariates associated with mortality. ResultsRenal function worsened after UF in 17 of the 20 UF treatments (baseline vs. post UF creatinine: 164±58 vs. 185±69μmol/l, P<0.01). ΔCVO2 was significantly associated with Δcreatinine [β-coefficient of −1.3 95%CI (−1.8 to −0.7), P<0.001] and remained significantly associated with Δcreatinine after considering changes in SBP, HR and PCV [P<0.001]. Ten (59%) patients died at 1-year and 15(88%) by 2-years. Δcreatinine was independently associated with mortality (adjusted-hazard ratio 1.03 (1.01 to 1.07) per 1μmol/l increase in creatinine; P=0.02). ConclusionsHaemodynamic changes during UF as measured by the surrogate of cardiac output was associated with Δcreatinine. Worsening renal function at end of UF treatment occurred in the majority of patients and was associated with mortality.

The Effect of Pulsatile Versus Nonpulsatile Blood Flow on Viscoelasticity and Red Blood Cell Aggregation in Extracorporeal Circulation.

BackgroundExtracorporeal circulation (ECC) can induce alterations in blood viscoelasticity and cause red blood cell (RBC) aggregation. In this study, the authors evaluated the effects of pump flow pulsatility on blood viscoelasticity and RBC aggregation.MethodsMongrel dogs were randomly assigned to two groups: a nonpulsatile pump group (n=6) or a pulsatile pump group (n=6). After ECC was started at a pump flow rate of 80 mL/kg/min, cardiac fibrillation was induced. Blood sampling was performed before and at 1, 2, and 3 hours after ECC commencement. To eliminate bias induced by hematocrit and plasma, all blood samples were adjusted to a hematocrit of 45% using baseline plasma. Blood viscoelasticity, plasma viscosity, hematocrit, arterial blood gas analysis, central venous O2 saturation, and lactate were measured.ResultsThe blood viscosity and aggregation index decreased abruptly 1 hour after ECC and then remained low during ECC in both groups, but blood elasticity did not change during ECC. Blood viscosity, blood elasticity, plasma viscosity, and the aggregation index were not significantly different in the groups at any time. Hematocrit decreased abruptly 1 hour after ECC in both groups due to dilution by the priming solution used.ConclusionAfter ECC, blood viscoelasticity and RBC aggregation were not different in the pulsatile and nonpulsatile groups in the adult dog model. Furthermore, pulsatile flow did not have a more harmful effect on blood viscoelasticity or RBC aggregation than nonpulsatile flow.

Does the infusion rate of fluid affect rapidity of mean arterial pressure restoration during controlled hemorrhage

ObjectiveThis study aimed to compare 2 fluid infusion rates of lactated Ringer (LR) and hydroxyethyl starch (HES) 130/0.4 on hemodynamic restoration at the early phase of controlled hemorrhagic shock. MethodsFifty-six anesthetized and ventilated piglets were bled until mean arterial pressure (MAP) reached 40 mm Hg. Controlled hemorrhage was maintained for 30 minutes. After this period, 4 resuscitation groups were studied (n=14 for each group): HES infused at 1 or 4mL/kg per minute or LR1 infused at 1 or 4mL/kg per minute until baseline MAP was restored. Hemodynamic assessment using PiCCO monitoring and biological data were collected. ResultsTime to restore baseline MAP ±10% was significantly lower in LR4 group (11±11 minutes) compared to LR1 group (41±25 minutes) (P=.0004). Time to restore baseline MAP ±10% was significantly lower in HES4 group (4±3 minutes) compared to HES1 (11±4 minutes) (P=.0003). Time to restore baseline MAP ±10% was significantly lower with HES vs LR whatever the infusion rate.No statistically significant difference was observed in cardiac output, central venous saturation, extravascular lung water, and arterial lactate between 4 and 1 mL/kg per minute groups. ConclusionsIn this controlled hemorrhagic shock model, a faster infusion rate (4 vs 1mL/kg per minute) significantly decreased the time for restoring baseline MAP, regardless of the type of infused fluid. The time for MAP restoration was significantly shorter for HES as compared to LR whatever the fluid infusion rate.

Clonidine as a First-Line Sedative Agent After Neonatal Cardiac Surgery: Retrospective Cohort Study.

To determine the cardiovascular tolerance of clonidine used as a first-line sedative after cardiac surgery in small infants. Retrospective chart review. A tertiary and quaternary referral cardiac PICU. All infants younger than 2 months who received a clonidine infusion for sedation after cardiac surgery from October 2011 to July 2013. None. Heart rate, blood pressure, central venous and left atrial pressure, vasoactive inotropic score, volume of fluid bolus, and lactate and central mixed venous saturation were assessed. Preinfusion values were compared with postinfusion values. Of 224 potentially eligible patients, only 23 infants met inclusion criteria, as most patients only received high doses of morphine and some received midazolam instead of clonidine. Clonidine administration was started at a median of 12 hours after surgery (Q1-Q3, 5-23), and infusion rate was 0.5-2 μg/kg/hr for a median duration of 30 hours (Q1-Q3, 12-54). Heart rate decreased (maximal mean decrease: 12% [149 beats/min (SD, 17) to 131 beats/min (SD, 17)]; p < 0.0001). Apart from a transient and limited drop in diastolic blood pressure of 13% (maximal mean decrease: from 42.8 mm Hg [SD, 5.9] to 37.1 mm Hg [SD, 4.0]; p = 0.018), all other cardiovascular variables were stable or improved. A contemporaneous cohort of patients who received midazolam, did so sooner after surgery, stayed longer in the PICU and showed less favorable hemodynamics. IV clonidine as sedative added to morphine in selected patients seems hemodynamically safe. The observed decrease in heart rate and diastolic blood pressure seems of minimal clinical importance as all other hemodynamic variables remained stable or improved. The safety of clonidine given early after cardiac surgery as alternative to midazolam merits further study.

Venous saturation : Between oxygen delivery and consumption

Venous saturation is an important parameter to assess the ratio between oxygen delivery and oxygen consumption for both intensive care medicine and during perioperative care. Mixed venous saturation (SvO2) is the most reliable parameter in this setting. Due to the high invasiveness of measuring mixed venous saturation, the less invasive central venous saturation (ScvO2) has been entrenched for determining the balance of oxygen delivery and consumption. However, central venous saturation is inferior compared to mixed venous saturation as it does not cover the lower part of the body, including splanchnic perfusion. Nevertheless, studies have shown that central venous saturation is a reliable marker for goal-directed therapy in intensive care medicine, especially in patients with septic or hemorrhagic shock. Furthermore, central venous saturation has deep impact as a prognostic factor concerning morbidity and mortality. It has to be mentioned that not only decreased venous saturations but also elevated venous saturations are associated with poor outcome. Besides mixed venous and central venous saturation, intensivists and anesthesiologists focus on the central venous-arterial pCO2 difference (dCO2). An elevated dCO2 is associated with poor outcome in patients after cardiac surgery or patients with sepsis. Yet, further investigations have to be performed to implement the dCO2 as a reliable marker in daily routine.

Prognostic value of gasometric parameters of carbon dioxide in resuscitation of septic patients. A bibliography review

The anaerobic metabolism is the cornerstone in physiopathology of septic shock. Nowadays we have both the central or mixed venous oxigen saturation and lactate levels to monitoring the metabolism in septic patients. Some studies have shown that normalisation of systemic haemodynamic and oxygen metabolism variables not prevent progression to multiorgan damage and death.Recently has been proposed the venous-to-arterial carbon dioxide difference (ΔpvaCO2) as an alternative marker of tissue hypoperfusion, like Cardiac Index. High ΔpvaCO2 predicts adverse outcomes. Also has been proposed both, the ratio between the ΔpvaCO2 and arterial-to-venous oxygen content difference (ΔCavO2): ΔpvaCO2/ΔCavO2; and, the ratio between venous-to-arterial carbon dioxide difference (ΔCvaCO2) and ΔCavO2: ΔCvaCO2/ΔCavO2, as markers of anaerobic metabolism. Both of high ratios are related to high levels of lactate and worse prognosis. Therefore in patients with sepsis the combination of markers of resuscitation could be important to improve the outcomes.

Evolution of regional oxygen saturation in the peri-operative of thoracic surgery and its relationship with central venous saturation

ObjectiveTo study the relationship between the values of SvcO2 and SrcO2 in lung resection with one lung ventilation (OLV) and changes in these variables and mean arterial pressure (MAP) and arterial oxygen saturation (SpO2) during the perioperative period. Material and methodsProspective, observational study of 25 patients in whom pulmonary resection was performed with OLV. The values of MAP, SpO2, SvO2, and SrcO2 were recorded at 6 different times: (1) baseline; (2) double-lung ventilation before the OLV (VBP1); (3) during OLV; (4) after double-lung ventilation (VBP2); (5) 30min after surgery, and (6) 6h after surgery. ResultsThe SrcO2 showed a significant increase from baseline to starting ventilation (65.72±9.05% vs 70.44±7.24%; p<.01). There were no significant changes in their values at the different intraoperative times. Post-operatively, as in the case of the SvcO2, a significant decrease (p<.001) of its value compared with the previous value was observed. ConclusionsSrcO2 showed a significant increase after induction of anaesthesia and initiation of mechanical ventilation compared to baseline, and a significant decrease at the end of surgery after extubation in the immediate postoperative period. Being a tissue monitoring, non-invasive technique and with continuous values it can alert the clinician of changes in the ratio of oxygen consumption (VO2) to oxygen delivery (DO2) at times of greatest risk, such as OLV, extubation, and the early postoperative period.

Comparison of high glucose concentration blood and crystalloid cardioplegia in paediatric cardiac surgery: a randomized clinical trial.

This study investigates the effects of high glucose content on patients undergoing cold crystalloid versus cold blood cardioplegia in terms of early clinical results, functional myocardial recovery and ischaemia-reperfusion injury in patients undergoing repair of acyanotic cardiac lesions. Patients were randomly assigned to receive either crystalloid (n = 31) or blood cardioplegia (n = 31). Early clinical results were assessed. Changes in left ventricular fractional shortening, arterial blood lactate levels, central venous saturation, cardiac Troponin I release and blood glucose concentration were measured during the first 24 h after ischaemia. There was no significant difference in clinical outcomes and postoperative complication rates between groups. The postoperative changes in left ventricular function, lactate levels, central venous saturation and Troponin I were not significantly different between groups. The use of crystalloid cardioplegia was associated with significant increases in serum glucose compared with blood cardioplegia. A high glucose content blood cardioplegia does not show any advantage compared with crystalloid cardioplegia in terms of clinical outcomes, functional recovery and the degree of ischaemic injury in infants and children undergoing repair of acyanotic heart lesions. High glucose concentration of the cardioplegic solution might potentiate ischaemia-reperfusion injury and diminish the beneficial effects of blood cardioplegia.