Mixed Venous Saturation Research Articles

Monitoring and complications during neonatal/pediatric ECMO run

Extracorporeal membrane oxygenation (ECMO) is a commonly used form of mechanical circulatory support in children with congenital or acquired heart disease, and cardiac failure refractory to conventional medical treatments.1 The cardiac output is partially or completely provided by the ECMO machine. To assess how much support is needed at any given time, a constant balance of oxygen delivery and oxygen consumption is required. Permanent monitoring of flow, hemoglobin, arterial, and mixed venous saturations are key elements to provide the needed understanding and continuous guidance of body requirements, aiming at controlling and maintaining optimal management of the ECMO patient. Although ECMO is lifesaving in many circumstances, it bares challenges and certain risks of complications. Despite bioline-coated circuits, anticoagulation is required. Measurement of activated clotting time (ACT) and activated partial thromboplastin time (APTT) are both used to guide anticoagulation, but it is unclear which method is the best, and constant monitoring of the hemoglobin level allows the early detection of internal and external bleeding.2 For children, sedation and analgesia, most often in combination with paralysis, is unavoidable for a smooth ECMO run. On the other hand, with such treatment on board, it is almost impossible to assess the neurological status of the patient on ECMO. Different monitoring tools, such as cerebral near infrared spectroscopy (NIRS) and serial brain ultrasound studies, are used to estimate brain integrity and function, but further research is needed to show which methods are the most practical and useful to achieve a favorable outcome.3 Nutrition in critically ill children is known to be crucial but debated how to achieve as the gut perfusion can be impaired and therefore the risk of necrotizing enterocolitis (NEC) is increased. It is discussed if somatic perfusion by NIRS monitoring can help to avoid NEC.4 The kidney function is often impaired in these critically ill children and careful monitoring of kidney function and urine output leads the decision when to start which type of renal replacement therapy for renal clearance and/or fluid removal. Techniques available include peritoneal dialysis or continuous renal replacement therapy (CRRT) incorporated with the ECMO circuit. Medication dosing is under discussion in many centers as the circulatory volume is higher than normal. Adjustment of medication dosing could consequently be of great importance. Close monitoring of medications where toxic levels can be reached is crucial to avoid further damage to the patient's organ functions.

Can venous saturations from the central venous line and the venous side of the heart–lung machine be interchangeable with mixed venous saturation from the pulmonary artery in children undergoing open-heart surgery?

Background Mixed venous oxygen saturation has been advocated as an indirect index of tissue oxygenation. This study evaluated whether venous oxygen saturation from the central venous line (CVL) or the venous side of the cardiopulmonary bypass (CPB) was interchangeable with mixed venous oxygen saturation from the pulmonary artery in children undergoing cardiac surgery for correction of congenital heart defects. Patients and methods Forty children ranging in age from 1 to 15 years undergoing correction for congenital heart procedures with CPB were included in this study. Simultaneous samples were taken from the CVL, the pulmonary artery, and from the venous side of the CPB after 10 min on full CPB and at the end of surgery before weaning from CPB. Bland and Altman’s analysis was carried out to study the agreement between different venous oxygen saturation. Results Insignificant correlations were observed between venous oxygen saturation from the pulmonary artery, the CVL, and the venous site of the CPB. Wide limits of agreements were observed between the venous oxygen saturation in the pulmonary artery with that in the CVL (14.21–−15.32), and also with that in the venous side of the CPB (34.34–−33.18). A wide limit of agreement was observed between venous oxygen saturation in the venous side of the CPB with that in the CVL (28.24–−31.67). Conclusion Venous saturations from the CVL, and from venous side of CPB are not interchangeable with mixed venous saturation from the pulmonary artery in children undergoing open-heart surgery.

Recent advances in bedside microcirculation assessment in critically ill patients.

Parameters related to macrocirculation, such as the mean arterial pressure, central venous pressure, cardiac output, mixed venous saturation and central oxygen saturation, are commonly used in the hemodynamic assessment of critically ill patients. However, several studies have shown that there is a dissociation between these parameters and the state of microcirculation in this group of patients. Techniques that allow direct viewing of the microcirculation are not completely disseminated, nor are they incorporated into the clinical management of patients in shock. The numerous techniques developed for microcirculation assessment include clinical assessment (e.g., peripheral perfusion index and temperature gradient), laser Doppler flowmetry, tissue oxygen assessment electrodes, videomicroscopy (orthogonal polarization spectral imaging, sidestream dark field imaging or incident dark field illumination) and near infrared spectroscopy. In the near future, the monitoring and optimization of tissue perfusion by direct viewing and microcirculation assessment may become a goal to be achieved in the hemodynamic resuscitation of critically ill patients.

Invited Commentary

Does the likeness in means and ranges of hemoglobin (Hgb) from birds to mammals suggest that this physiological equilibrium has emerged more than once by natural selection? Is it by chance that the “ideal hematocrit” across the animal kingdom, when plotted against viscosity, usually follows a similar concave curve, peaking around a value of 40? Are events that evolved to maximize survival and reproductive fitness hundreds of millions of years ago relevant to perioperative management of patients? And should the anemia of a child with a moderately sized ventricular septal defect be corrected to avoid surgery? Cholette and colleagues [1Cholette J.M. Swartz M.F. Rubenstein J. et al.Outcomes using a conservative versus liberal red blood cell transfusion strategy in infants requiring cardiac operation.Ann Thorac Surg. 2017; 103: 206-215Abstract Full Text Full Text PDF PubMed Scopus (39) Google Scholar] do not address these questions. I congratulate them, however, for their perseverance (this is a follow-up study) and for completing likely a difficult study. Further, they clearly show that one can avoid red blood cell (RBC) transfusion in most children after biventricular repair and in a reasonable fraction of those palliated with cavopulmonary or systemic-to-pulmonary artery shunting. They randomized 134 patients after biventricular and 57 patients after palliative surgery (including 12 s/p Norwood), to either a “restrictive” (Hgb of 7.0) or “liberal” (Hgb of 9.0 g/dL) threshold for transfusion. They report similar lactate, avO2 differences, and clinical results between the two groups and, therefore, infer that clinical judgment should guide transfusion decisions. But whose judgment? Once a critical care colleague said that just because you can stand in a canoe in the middle of the lake, it does not mean you should. Therefore, without specific guidelines, one is left with the judgment of one clinician versus another. Most would agree that RBC transfusions are not without risk; for example, many have shown the associated increased risk of infection. The typical reason (tachycardia, low blood pressure, low urine output, low mixed venous saturations) for treating anemia are practical starting points, but some patients have much less reserve than others do, and clinical circumstances may mask or decrease the potential for applicability of such features. The baby with pulmonary atresia/intact ventricular septum and RV dependent coronary circulation and coronary atresia may not tolerate heart rates in the 150s or 160s, let alone the 170s or 180s. Lactate, as used by the authors, is a late marker of tissue hypoxia, only to rise with anaerobic glycolysis. Other notable findings from the study include the difference in transfusion rates between the two groups: one transfusion. Authors provide no information on number of laboratory tests, which is perhaps the primary driving force for blood loss after surgery (all patients started with same baseline Hgb). It is tempting to speculate that the restrictive approach perhaps influenced the perioperative management. If true, adopting a restrictive strategy would be a laudable goal in lessening the number of such tests. It is also notable that 4 of the 6 babies for whom the restrictive strategy was violated were newborns who had undergone one form or another of arch reconstruction. Over 80 years ago, Robin Fahraeus remarked on the fall of hematocrit in blood flowing through smaller-caliber tubes. Future observations confirmed the differential segregation of RBCs and plasma in divisions of microvasculature, whether by default or because of vasoactive agents. These observations and other experiments of nature (e.g., the Antarctic Icefish compensates for no Hgb by having a much larger heart, high stroke volume, and dense capillary network) highlight that while an arbitrary Hgb value is not a signal for transfusion, great caution should be exercised when deciding whether a patient should or should not receive a transfusion. The decision not to transfuse could be just as dangerous as the one to transfuse. Outcomes Using a Conservative Versus Liberal Red Blood Cell Transfusion Strategy in Infants Requiring Cardiac OperationThe Annals of Thoracic SurgeryVol. 103Issue 1PreviewThe optimal hemoglobin for infants after cardiac operation is unknown. Red blood cells (RBCs) are commonly transfused to maintain high hemoglobin concentrations in the absence of a clinical indication. We hypothesized that infants can be managed with a postoperative conservative RBC transfusion strategy, resulting in lower daily hemoglobin concentrations, without evidence of impaired oxygen delivery (ie, lactate, arteriovenous oxygen difference [avO2diff]), or adverse clinical outcomes. Full-Text PDF

Mechanically assisted bidirectional cavopulmonary shunt in neonates and infants: An acute human pilot study

ObjectivePoor survival following surgical palliation for hypoplastic left heart syndrome (HLHS) raises the question of the need for a paradigm shift. This is the first human study to investigate the possibility of primary “in-series” palliation in neonates and infants with HLHS in an acute setting with the aid of 2 types of mechanical assist: superior vena cava (SVC)–to–pulmonary artery (PA) pump assist and SVC–to–right atrium (RA) oxygenation assist. MethodsBy rearranging the cannula sites and flow rates for modified ultrafiltration, 2 types of mechanically assisted bidirectional cavopulmonary shunt (BCPS) circulation were simulated for 20 minutes. Three neonates undergoing a stage I Norwood procedure were assigned to SVC-PA pump assist, and 3 infants undergoing stage II BCPS were assigned to SVC-RA oxygenation assist. Hemodynamic parameters, blood gas values, and arterial (SaO2) and regional cerebral tissue (rCTO2) saturations were analyzed. ResultsAll 6 patients completed the study without hemodynamic compromise. In the SVC-PA pump assist group, a mean arterial pressure >40 mm Hg was maintained. SVC pressure was lower (P = .01) and cerebral perfusion pressure (CPP) was higher (P = .03) during the last 10 minutes of assist compared with Norwood physiology. SaO2 >80%, rCTO2 >60%, and mixed venous saturation ≥59% were maintained, comparable to values with Norwood physiology. In the SVC-RA oxygenation assist group, with full or 50% support, mean blood pressure >50 mm Hg, SVC pressure <15 mm Hg, mixed venous saturation >50%, and CPP >40 mm Hg were maintained, which were comparable to BCPS physiology. ConclusionsTwo types of mechanical assist to support primary in-series palliation are feasible in the acute setting. Both modes of mechanical assist maintained oxygenation, as well as systemic and cerebral perfusion.

Bone-Specific Alkaline Phosphatase in Patients Who Have Undergone the Fontan Operation.

Bone-specific alkaline phosphatase (BALP) is produced by osteoblasts. A recent series noted a positive association between cardiac index (CI) and BALP in patients with Fontan circulation. CI is low at baseline in these patients, and small decreases in CI may result in diverting of blood away from bone. We prospectively enrolled 15 patients (males≤14 yo, females≤12 yo) who had previously undergone Fontan operation and were undergoing cardiac catheterization. Serum BALP was measured at catheterization, and analysis performed to evaluate association between age-/gender-specific BALP z-score and CI as well as other patient variables. The median age at catheterization was 5.6years (3.1-13.1), and time from Fontan was 1.5years (0.1-12.1). The median superior vena cava saturation (SVC) was 65% (52-74), median average between SVC and inferior vena cava (IVC) saturations was 62.5% (51-70), and median CI was 3.8L/min/m(2) (2.0-8.4). The median BALP was 65IU/L and BALP z-score was -2.1 (-3.2 to 0.9). BALP z-score was not associated with CI (ρ=-0.1, p=0.7), but a positive correlation was noted with the average of SVC and IVC saturation (ρ=0.5, p=0.052) and with SVC saturation (ρ=0.4, p=0.07), both nearly reaching statistical significance. In our cohort of children with Fontan circulation undergoing catheterization, BALP z-score was not associated with CI, but an association with estimates of mixed venous saturation was noted that nearly reached statistical significance. We hypothesize that BALP is a marker of oxygen delivery in those with Fontan circulation and may represent a valuable biomarker in this population.

Transition from parenteral to oral treprostinil in pulmonary arterial hypertension

Parenteral prostanoids are effective treatment for pulmonary arterial hypertension, but long-term pump infusion systems have significant delivery-related safety and convenience limitations. Subjects with a favorable risk profile transitioned from parenteral to oral treprostinil using a protocol-driven titration during 5 days of inpatient observation. Baseline and Week 24 assessments included 6-minute walk distance, echocardiogram, right heart catheterization, pharmacokinetics, treatment satisfaction and quality of life. Thirty-three subjects (76% female, mean age 50 years) enrolled; 85% were using subcutaneous treprostinil with a median dose of 57 (range 25 to 111) ng/kg/min. Participants were using background, approved non-prostanoid therapy, including 9 on 2 oral therapies; baseline right atrial pressure and cardiac output were in the normal range. All 33 subjects transitioned to oral treprostinil therapy within 4 weeks, but 2 transitioned back to parenteral drug before Week 24. At Week 24, subjects were taking a median total daily dose of 44 (15 to 75) mg, with 25 of 31 using a 3-times-daily regimen at 7- to 9-hour intervals. The 6-minute walk distance was preserved (median +17 m [-98 to 95 m]) at its baseline of 446 m. Hemodynamic variables, including pulmonary vascular resistance, were similar at Week 24 except for mixed venous saturation, which dropped from a median of 71% to 68% (p < 0.001). Overall quality of life and treatment satisfaction measures did not change; however, mood-related symptom and treatment convenience subscores improved. Common adverse effects included headache, nausea, flushing and diarrhea. Lower risk patients managed on parenteral treprostinil may be candidates for transition to a more convenient, oral form of the drug.

Survival protection by bodyweight in isolated scleroderma-related pulmonary artery hypertension.

In chronic heart failure (CHF) due to systemic cardiovascular disease, obese patients have better survival. Bodyweight versus survival was analyzed post hoc in subjects with limited scleroderma (SSc) and isolated pulmonary artery hypertension (PAH), i.e. with CHF due to pulmonary vascular disease. Rheumatologists referred scleroderma subjects for evaluation, and PAH was ascertained by right heart catheterization (RHC). Forty-nine SSc-PAH subjects were stratified by body mass index (BMI): obese 7 (14.3%), overweight 11 (22.4%), normal weight 21 (42.9%), and underweight 10 (20.4%) for 24-month follow-up and pooled together for long-term 72-month follow-up. Survival was analyzed by Kaplan-Meier method. Multivariate Cox proportional hazards modeling helped to assess variables associated to survival. At 24months (17 events), survival increases with BMI across four groups (logrank for trend P=0.031). By Cox multivariate mortality, best model included: BMI (P=0.043), low lung diffusion (DLco, P=0.007), and reduced stroke volume index (SVI, P=0.017). At 72month (37 events), higher BMI values were associated with better survival but not significantly (P=0.076). By multivariate modeling BMI did not enter any model, whereas low DLco entered all (P<0.001). Also low SVI (P=0.02) and low mixed venous saturation (SvO2, P=0.009) were associated with the prognosis. From PAH diagnosis to final event, BMI had small (5.4%), but significant decline (P<0.001). This is ascribed to CHF progression, and may explain BMI predictive power weakening. The results suggest BMI decline should be contrasted, DLco is useful for screening and with SVI and SvO2 for assessing prognosis and treatment.

The Effects of Anesthesia, Muscle Paralysis, and Ventilation on the Lung Evaluated by Lung Diffusion for Carbon Monoxide and Pulmonary Surfactant Protein B

Surv Anesthesiol 2016;60(2):59–59 Impaired gas exchange is common after the induction of general anesthesia and is mainly associated with reduced oxygenation. Although measurement of oxygenation is the most common method used to assess this impairment, it is not very sensitive because changes in mixed venous saturation influence arterial oxygenation regardless of lung gas exchange.

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.

The Impella® Recover mechanical assist device in acute cardiogenic shock: a single-centre experience of 66 patients.

Short-term ventricular assist devices are more frequently used in patients with acute cardiogenic shock. The aim of this study was to evaluate its effect on haemodynamic parameters, as well as the short- and long-term outcome and complication rate associated with the device. All patients treated with the Impella® Recover device at our centre from 2003 to 2014 (n = 66) were included in this study, and follow-up time was 2.9 (±0.4) years. Data were obtained through patient records and the population register. Patient-related factors, preimplantation and early postimplantation haemodynamic and biochemical parameters were analysed. Characteristics of survivors and non-survivors were compared. The device was implanted in 66 patients and 58% (38/66) were alive at 30 days post-implantation. The mean duration of support was 7.4 (±0.8) days. Mean time in the intensive care unit was 24 (±4) days. Following device implantation, patients' cardiac index improved from 2.1 l/min/m(2) (±0.20) to 3.8 l/min/m(2) (±0.20) at Day 7, mixed venous saturation increased from 56% (±2.0) to 68% (±1.2) and diuresis increased from 69 ml/h (±9) at device insertion to 105 ml/h (±19) at Day 7 on support. Central venous pressure, lactate levels and inotropic support decreased on support. No difference between survivors and non-survivors was established. No correlation was established between preimplant parameters and 30-day mortality. The Impella® Recover device improved haemodynamics in patients with acute cardiogenic shock. Still, 30-day mortality remains high and future studies must focus on the optimal timing of placement of the device.

Valor pronóstico de los parámetros gasométricos del dióxido de carbono en pacientes con sepsis. Una revisión bibliográfica

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 normalization of systemic hemodynamic 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.

The effects of thoracic epidural analgesia on oxygenation and pulmonary shunt fraction during one-lung ventilation: an meta-analysis.

BackgroundThe aim of our study is to compare the effects of thoracic epidural analgesia combined with general anesthesia (GA) vs. general anesthesia on oxygenation and pulmonary shunt fraction during one-lung ventilation (OLV).MethodsLiterature research was firstly conducted for studies related to comparison of epidural anesthesia combined with GA vs. GA with reporting of hemodynamic and oxygenation variables and published from Jan 1990 to Jan 2014 in EMBAS, MEDLINE and Cochrane Central Register of Controlled Trials databases. The studies were reviewed and data were extracted and analyzed using fixed-effect and random-effect models.ResultsThere are 14 trials with 60 separate comparisons enrolling 653 patients for analysis. Regarding systemic hemodynamics, thoracic epidural analgesia decreased the mean arterial pressure and mean pulmonary arterial pressure with weighted mean difference 95 % confidence interval (−6.64 [−9.57 to −3.71] vs. -6.33 [−9.25 to −3.41] and −3.18 [−5.07 to −1.28] vs. -2.05 [−3.35 to −0.75]) respectively at the two measurements time, however, only decreasing heart rate and systemic vascular resistance (−3.28 [−5.98 to −0.67] and −319.99 [−447.05 to −192.94]) over the first 30 min after OLV. For oxygenation variables, thoracic epidural analgesia is associated with significant reduction in partial arterial oxygen pressure, mixed arterial saturation of oxygenation and increased pulmonary venous admixture fraction compared to general anesthesia with weighted mean difference 95 % confidence interval (−16.52 [−21.98 to − 11.05] vs. − 14.23 [−20.81 to − 7.65]), (0.74 [0.33 to 1.15] vs. − 0.63 [−1.23 to −0.04]) and (2.53 [1.35 to 3.72] vs. 2.77 [1.81 to 3.74]) respectively before and after 30 min of one-lung ventilation. A decrease in mixed venous saturation of oxygenation occurred after 30 min of OLV (−2.39 [−3.73 to −0.99]). Besides, a higher mean value of airway pressure was found in the thoracic epidural analgesia with weighted mean difference 95 % confidence interval (1.95 [1.61 to 2.28] vs. 0.87 [0.54 to 1.20]) at the measurements.ConclusionBased on the existing limited data puts forward recommendations for cautious usage of thoracic epidural analgesia in case of underlying risks in lower systemic hemodynamics, decreased partial arterial oxygen pressure but increases pulmonary shunt during one-lung ventilation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12871-015-0142-5) contains supplementary material, which is available to authorized users.

Circulation : Clinical Summaries

<i>Circulation</i> : Clinical Summaries

Adjusting for Risk Associated With Pediatric and Congenital Cardiac Catheterization: A Report From the NCDR IMPACT Registry.

As US health care increasingly focuses on outcomes as a means for quantifying quality, there is a growing demand for risk models that can account for the variability of patients treated at different hospitals so that equitable comparisons between institutions can be made. We sought to apply aspects of prior risk-standardization methodology to begin development of a risk-standardization tool for the National Cardiovascular Data Registry (NCDR) IMPACT (Improving Pediatric and Adult Congenital Treatment) Registry. Using IMPACT, we identified all patients undergoing diagnostic or interventional cardiac catheterization between January 2011 and March 2013. Multivariable hierarchical logistic regression was used to identify patient and procedural characteristics predictive of experiencing a major adverse event after cardiac catheterization. A total of 19,608 cardiac catheterizations were performed between January 2011 and March 2013. Among all cases, a major adverse event occurred in 378 of all cases (1.9%). After multivariable adjustment, 8 variables were identified as critical for risk standardization: patient age, renal insufficiency, single-ventricle physiology, procedure-type risk group, low systemic saturation, low mixed venous saturation, elevated systemic ventricular end-diastolic pressure, and elevated main pulmonary artery pressures. The model had good discrimination (C statistic, 0.70), confirmed by bootstrap validation (validation C statistic, 0.69). Using prior risk-standardization efforts as a foundation, we developed and internally validated a model to predict the occurrence of a major adverse event after cardiac catheterization for congenital heart disease. Future efforts should be directed toward further refinement of the model variables within this large, multicenter data set.

Abstract 17532: Impact of High Hepatic Wedge Pressure, Portal Hypertension, on Hemodynamics and Liver Function in Patients After the Fontan Operation

Background: Fontan circulation may be, in part, characterized by portal hypertension that can be estimated by hepatic vein wedge pressure (HWP). Purpose: To evaluate associations of HWP in cosecutive 318 Fontan patients (18±7 years old) during catheterization and compared the results with the hemodynamics, liver function and the related plasma biomarkers. HWP significantly correlated positively with inferior vena cava pressure (IVCP), pulmonary artery resistance (Rp), ration of Rp to systemic artery resistance (Rs) (Rp/Rs), and cardiac index and negatively with Rs and arterial and mixed venous oxgen saturations. Of those, high IVCP, low Rp and high Rp/Rs were independently correlated with high HWP (p&lt;0.05 for all). As for the liver function, HWP significantly correlated positively with plasma levels of total bilirubin (TB), hyaluronic acid, and type IV collagen (TyIV) and negatively with plasma levels of albumin and cholinesterase (ChE). Of those, ChE, TB and TyIV were independently correlated with high HWP (p&lt;0.01 for all). High HWP, low ChE, and high TyIV significantly correlated with high plasma nitric oxide products (p&lt;0.01). Conclusion: High HWP associates with a significant reduction of Rp and Rs with preserved cardiac output. This unique Fontan circulation with Rs-dominant reduction may be due to both portal hypertension and overproduction of nitric oxide secondary to liver dysfunction.

Tissue oxygen saturation as an early indicator of delayed lactate clearance after cardiac surgery: a prospective observational study.

BackgroundIn this observational study near infrared spectroscopy (NIRS) was evaluated as a non-invasive monitor of impaired tissue oxygenation (StO2) after cardiac surgery. StO2, cardiac output, mixed venous oxygen saturation and mean arterial pressure were compared with lactate clearance as established measure for sufficient tissue perfusion and oxygen metabolism.MethodsForty patients after cardiac surgery (24 aortocoronary bypass grafting, 5 heart valve, 3 ascending aorta and 8 combined procedures) were monitored until postoperative day 1 with NIRS of the thenar muscle (InSpectra™ StO2-monitor, Hutchinson Technology), a pulmonary-artery catheter and intermittent blood gas analyses for the assessment of lactate clearance.ResultsStO2 was reduced 4 h after surgery (75 ± 6 %), but recovered at day 1 (84 ± 5 %), while lactate concentration remained increased. Using uni- and multivariate regression analysis, minimum StO2 (r = 0.46, p <0.01) and cardiac index (r = 0.40, p <0.05) correlated with lactate clearance at day 1, while minimum mixed venous saturation and mean arterial pressure did not. In a receiver-operating characteristics (ROC) analysis, minimum StO2 (with a threshold of 75 %) predicted a lactate clearance <10 % at day 1 with an area under the ROC-curve of 0.83, a sensitivity of 78 % and a specificity of 88 %. In the subgroup with StO2 <75 %, troponin and creatine kinase MB were significantly increased at day 1.ConclusionsStO2 below 75 % in the first hours after surgery was a better early indicator of persistent impaired lactate clearance at day 1 than cardiac index, mixed venous oxygen saturation or mean arterial pressure.

Oxygen balance and systemic inflammation after cardio-pulmonary bypass in elderly patients with different intensive care duration

Background & Aim. The aim was to investigate the prognostic significance of oxygen balance and systemic inflammation after cardio-pulmonary bypass (CPB) in elderly patients (pts). Methods. We evaluated 78 pts aged more than 74 years old undergoing cardiac surgery. Mixed venous saturation (SvO2), oxygen delivery (DO2), oxygen consuption (VO2), O2 extraction rate (ERO2), arterio-venous O2 difference (A-V O2), lactate level after CPB, postoperative leukocytosis, intensive care unit (ICU) stay were registered. Data are given as mean SD. Student’s t-test was used with Po0.05 as significant. Results. Fifty two pts were discharged from ICU within one day after surgery (group 1). The rest 26 pts (group 2) had ICU staing 5 2 days, characterized by lover post-CPB DO2, VO2, ERO2, AV O2, higher SvO2, lactate (table). Leucocytes number had the significant (po0,05) dirrect correlation (r1⁄40.58) with SvO2, and inverse (r 0.64) – with A-V O2.