Low Systemic Vascular Resistance Index Research Articles

Accuracy of Cardiac Output Measured by Fourth-Generation FloTrac and LiDCOrapid, and Their Characteristics Regarding Systemic Vascular Resistance in Patients Undergoing Cardiac Surgery

The clinical use of less-invasive devices that calculate the cardiac output from arterial pressure waveform is increasing. The authors aimed to evaluate the accuracy and characteristics of the systemic vascular resistance index (SVRI) of the cardiac index measured by 2 less-invasive devices, fourth-generation FloTrac (CIFT) and LiDCOrapid (CILR), compared with the intermittent thermodilution technique, using a pulmonary artery catheter (CITD). This was a prospective observational study. This study was conducted at a single university hospital. Twenty-nine adult patients undergoing elective cardiac surgery. Elective cardiac surgery was used as an intervention. Hemodynamic parameters, CIFT, CILR, and CITD, were measured after the induction of general anesthesia, at the start of cardiopulmonary bypass, after completion of weaning from cardiopulmonary bypass, 30 minutes after weaning, and at sternal closure (135 measurements in total). The CIFT and CILR had moderate correlations with CITD (r=0.62 and 0.58, respectively). Compared with CITD, CIFT, and CILR had a bias of -0.73 and -0.61 L/min/m2, limit of agreement of -2.14-to-0.68 L/min/m2 and -2.42-to-1.20 L/min/m2, and percentage error of 39.9% and 51.2%, respectively. Subgroup analysis for evaluating SVRI characteristics showed that the percentage errors of CIFT and CILR were 33.9% and 54.5% in low SVRI (<1,200 dyne×s/cm5/m), 37.6% and 47.9% in moderate SVRI (1,200-1,800 dyne×s/cm5/m), 49.3% and 50.6% in high SVRI (>1,800 dyne·s/cm5/m2), respectively. The accuracy of CIFT or CILR was not clinically acceptable for cardiac surgery. Fourth-generation FloTrac was unreliable in high SVRI. LiDCOrapid was inaccurate across a broad range of SVRI, and minimally affected by SVRI.

Validation of cardiac output estimation using the fourth-generation FloTrac/EV1000™ system in patients undergoing robotic-assisted off-pump coronary artery bypass surgery.

The pulmonary artery catheter (PAC)-despite its invasiveness-remains the gold standard for cardiac output (CO) monitoring. The FloTrac system, a less invasive hemodynamic monitor has been developed, which estimates CO using arterial pressure waveform analysis without external calibration. Recently, an upgraded version of FloTrac system with improved algorithm to follow changes in vascular resistance was introduced into the market. The aim of this study was to assess the reliability of the CO estimated from the fourth-generation FloTrac/EV1000 system (COFT) compared to that measured with PAC using the thermodilution method (COPAC) during robotic-assisted off-pump coronary artery bypass (OPCAB) surgery. COFT and COPAC were obtained simultaneously at 4 predefined time points during robotic-assisted OPCAB: 5min after the induction of general anesthesia (T1), after starting one-lung ventilation (T2), after capnothorax (T3), and after mini-thoracotomy was performed (T4). The agreement of data was investigated by Bland-Altman analysis. Thirty-four patients were initially enrolled. After exclusion, 32 patients and a total of 128 paired CO measurements were obtained. The overall bias was 1.46L/min, the 95% limits of agreements were - 3.40 to 6.33L/min, and the percentage error was 72.98%. Regression analysis of the systemic vascular resistance index (SVRI) and the bias between COPAC and COFT showed that the bias was moderately correlated with the SVRI (r2 = 0.43; p < 0.0001). Despite a software upgrade, the reliability of the fourth-generation FloTrac/EV1000™ system during robotic-assisted OPCAB to estimate CO was not acceptable, especially in patients with low SVRI.

Hemodynamic differences between women and men with elevated blood pressure in China: A non-invasive assessment of 45,082 adults using impedance cardiography.

Whether there are sex differences in hemodynamic profiles among people with elevated blood pressure is not well understood and could guide personalization of treatment. We described the clinical and hemodynamic characteristics of adults with elevated blood pressure in China using impedance cardiography. We included 45,082 individuals with elevated blood pressure (defined as systolic blood pressure of ≥130 mmHg or a diastolic blood pressure of ≥80 mmHg), of which 35.2% were women. Overall, women had a higher mean systolic blood pressure than men (139.0 [±15.7] mmHg vs 136.8 [±13.8] mmHg, P<0.001), but a lower mean diastolic blood pressure (82.6 [±9.0] mmHg vs 85.6 [±8.9] mmHg, P<0.001). After adjusting for age, region, and body mass index, women <50 years old had lower systemic vascular resistance index (beta-coefficient [β] -31.7; 95% CI: -51.2, -12.2) and higher cardiac index (β 0.07; 95% CI: 0.04, 0.09) than men of their same age group, whereas among those ≥50 years old women had higher systemic vascular resistance index (β 120.4; 95% CI: 102.4, 138.5) but lower cardiac index (β -0.15; 95% CI: -0.16, -0.13). Results were consistent with a propensity score matching sensitivity analysis, although the magnitude of the SVRI difference was lower and non-significant. However, there was substantial overlap between women and men in the distribution plots of these variables, with overlapping areas ranging from 78% to 88%. Our findings indicate that there are sex differences in hypertension phenotype, but that sex alone is insufficient to infer an individual's profile.

Cutoff Values of Hemodynamic Parameters in Pediatric Refractory Septic Shock.

Background: Refractory septic shock can cause severe morbidities and mortalities in children. Resuscitation based on hemodynamics is important in children with critical illness. Thus, this study aimed to identify the hemodynamics of refractory septic shock associated with poor prognosis at an early stage to allow for timely interventions. Methods: We evaluated children with refractory septic shock admitted to a pediatric intensive care unit (PICU) and monitored their hemodynamics using a pulse index continuous cardiac output (PiCCO) system. The serial cardiac index (CI), systemic vascular resistance index (SVRI), and vasoactive–inotropic score (VIS) were recorded during the first 72 h after PICU admission. Results: Thirty-three children with refractory septic shock were enrolled. The SVRI and VIS were both associated with fatality from septic shock. The non-survivors had lower serial SVRI and higher VIS (both p < 0.05). Based on the area under the ROC curve, the SVRI was the predictor during the early resuscitative stage (first 36 h) in pediatric refractory septic shock. Conclusions: Both SVRI and VIS are predictors of mortality in children with refractory septic shock, and the SVRI is the powerful predictor of mortality in the early resuscitative stage. A low serial SVRI may allow for the early awareness of disease severity and strategies for adjusting vasoactive–inotropic agents to increase the SVRI.

Orthostatic Resiliency During Successive Hypoxic, Hypoxic Orthostatic Challenge: Successful vs. Unsuccessful Cardiovascular and Oxygenation Strategies.

Introduction: Rapid environmental changes, such as successive hypoxic-hypoxic orthostatic challenges (SHHOC) occur in the aerospace environment, and the ability to remain orthostatically resilient (OR) relies upon orchestration of physiological counter-responses. Counter-responses adjusting for hypoxia may conflict with orthostatic responses, and a misorchestration can lead to orthostatic intolerance (OI). The goal of this study was to pinpoint specific cardiovascular and oxygenation factors associated with OR during a simulated SHHOC.Methods: Thirty one men underwent a simulated SHHOC consisting of baseline (P0), normobaric hypoxia (Fi02 = 12%, P1), and max 60 s of hypoxic lower body negative pressure (LBNP, P2). Alongside anthropometric variables, non-invasive cardiovascular, central and peripheral tissue oxygenation parameters, were recorded. OI was defined as hemodynamic collapse during SHHOC. Comparison of anthropometric, cardiovascular, and oxygenation parameters between OR and OI was performed via Student’s t-test. Within groups, a repeated measures ANOVA test with Holm-Sidak post hoc test was performed. Performance diagnostics were performed to assess factors associated with OR/OI (sensitivity, specificity, positive predictive value PPV, and odd’s ratio OR).Results: Only 9/31 were OR, and 22/31 were OI. OR had significantly greater body mass index (BMI), weight, peripheral Sp02, longer R-R Interval (RRI) and lower heart rate (HR) at P0. During P1 OR exhibited significantly higher cardiac index (CI), stroke volume index (SVI), and lower systemic vascular resistance index (SVRI) than OI. Both groups exhibited a significant decrease in cerebral oxygenation (TOIc) with an increase in cerebral deoxygenated hemoglobin (dHbc), while the OI group showed a significant decrease in cerebral oxygenated hemoglobin (02Hbc) and peripheral oxygenation (TOIp) with an increase in peripheral deoxygenated hemoglobin (dHbp). During P2, OR maintained significantly greater CI, systolic, mean, and diastolic pressure (SAP, MAP, DAP), with a shortened RRI compared to the OI group, while central and peripheral oxygenation were not different. Body weight and BMI both showed high sensitivity (0.95), low specificity (0.33), a PPV of 0.78, with an OR of 0.92, and 0.61. P0 RRI showed a sensitivity of 0.95, specificity of 0.22, PPV 0.75, and OR of 0.99. Delta SVI had the highest performance diagnostics during P1 (sensitivity 0.91, specificity 0.44, PPV 0.79, and OR 0.8). Delta SAP had the highest overall performance diagnostics for P2 (sensitivity 0.95, specificity 0.67, PPV 0.87, and OR 0.9).Discussion: Maintaining OR during SHHOC is reliant upon greater BMI, body weight, longer RRI, and lower HR at baseline, while increasing CI and SVI, minimizing peripheral 02 utilization and decreasing SVRI during hypoxia. During hypoxic LBNP, the ability to remain OR is dependent upon maintaining SAP, via CI increases rather than SVRI. Cerebral oxygenation parameters, beyond 02Hbc during P1 did not differ between groups, suggesting that the during acute hypoxia, an increase in cerebral 02 consumption, coupled with increased peripheral 02 utilization does seem to play a role in OI risk during SHHOC. However, cardiovascular factors such as SVI are of more value in assessing OR/OI risk. The results can be used to implement effective aerospace crew physiological monitoring strategies.

Influence of early life risk factors and lifestyle on systemic vascular resistance in later adulthood: the cardiovascular risk in young Finns study

Purpose There are limited data available concerning the effects of lifetime risk factors and lifestyle on systemic hemodynamics, especially on systemic vascular resistance. The purpose of the study was to evaluate how lifetime cardiovascular risk factors (body mass index (BMI), high-density lipoprotein, low-density lipoprotein, triglycerides, systolic blood pressure, blood glucose) and lifestyle factors (vegetable consumption, fruit consumption, smoking and physical activity) predict systemic vascular resistance index (SVRI) and cardiac index (CI) assessed in adulthood. Materials and Methods Our study cohort comprised 1635 subjects of the Cardiovascular Risk in Young Finns Study followed up for 27 years since baseline (1980; aged 3–18 years, females 54.3%) who had risk factor and lifestyle data available since childhood. Systemic hemodynamics were measured in 2007 (aged 30–45 years) by whole-body impedance cardiography. Results In the multivariable regression analysis, independent predictors of the adulthood SVRI were childhood BMI, blood glucose, vegetable consumption, smoking, and physical activity (p ≤ .046 for all). Vegetable consumption, smoking, and physical activity remained significant when adjusted for corresponding adult data (p ≤ .036 for all). For the CI, independent predictors in childhood were BMI, systolic blood pressure, vegetable consumption, and physical activity (p ≤ .044 for all), and the findings remained significant after adjusting for corresponding adult data (p ≤ .046 for all). The number of childhood and adulthood risk factors and unfavourable lifestyle factors was directly associated with the SVRI (p < .001) in adulthood. A reduction in the number of risk factors and unfavourable lifestyle factors or a favourable change in BMI status from childhood to adulthood was associated with a lower SVRI in adulthood (p < .001). Conclusion Childhood BMI, blood glucose, vegetable consumption, smoking and physical activity independently predict systemic vascular resistance in adulthood. A favourable change in the number of risk factors or BMI from childhood to adulthood was associated with lower vascular resistance in adulthood.

Degree of Portal and Systemic Hemodynamic Alterations Predict Recurrent AKI and Chronic Kidney Disease in Patients With Cirrhosis.

The relevance of hemodynamic derangements on the incidence of recurrent acute kidney injury (AKI) and chronic kidney disease (CKD) in patients with cirrhosis is largely unknown. Consecutive patients with cirrhosis with a complete record of baseline hemodynamics were followed for identifying risk factors for the development of recurrent AKI and CKD by using negative binomial regression and competing risk analysis, respectively. Consecutive patients with cirrhosis (n = 2013, age 50.1 ± 11.8 years, 80% male, Child A:B:C percentage 13.7:52.9:33.4, and mean Child‐Turcotte‐Pugh score 8.6 ± 1.8) were enrolled, 893 (44.3%) of whom received beta‐blockers, with 44.2% responders. Prior AKI was noted in 12.4% at enrollment. At a median follow‐up of 379 (interquartile range: 68‐869) days, AKI developed at a rate of 0.37 episodes per person‐year, and 26% patients developed CKD. A lower mean number of AKI episodes (0.05 ± 0.25 vs. 0.42 ± 0.868; P < 0.001), CKD (subdistribution hazard ratio 0.74 [0.54‐1.02]), and mortality (hazard ratio 0.21 [0.06‐0.73]) were observed in beta‐blocker responders. Albuminuria was an independent risk factor for recurrent AKI, CKD, and mortality (P < 0.05). Lower systemic vascular resistance index predicted hemodynamic response (odds ratio 2.04 [1.29‐3.22]), cumulative AKI episodes (ratio of means 0.10 [0.08‐0.14]), and development of CKD (subdistribution hazard ratio 0.70 [0.58‐0.83]). Higher hepatic venous pressure gradient (≥17 mm Hg) predicted AKI episodes (ratio of means 1.76 [1.32‐2.35]) but not CKD. Conclusion: High portal pressure and severe vasodilatation predispose patients with cirrhosis to repeated AKI episodes and development of CKD. Response to beta‐blockers and therapies targeting the vasodilatory state could prevent frequent AKI and the risk of CKD development. Albuminuria could serve as an early marker of renal dysfunction in patients with cirrhosis.

Hemodynamic Predictors for Sepsis-Induced Acute Kidney Injury: A Preliminary Study.

The aim of our study was to assess the association between the macrohemodynamic profile and sepsis induced acute kidney injury (AKI). We also investigated which minimally invasive hemodynamic parameters may help identify patients at risk for sepsis-AKI. We included 71 patients with sepsis and septic shock. We performed the initial fluid resuscitation using local protocols and continued to give fluids guided by the minimally invasive hemodynamic parameters. We assessed the hemodynamic status by transpulmonary thermodilution technique. Sequential organ failure assessment (SOFA score) (AUC 0.74, 95% CI 0.61–0.83, p < 0.01) and cardiovascular SOFA (AUC 0.73, 95% CI 0.61–0.83, p < 0.01) were found to be predictors for sepsis-induced AKI, with cut-off values of 9 and 3 points respectively. Persistent low stroke volume index (SVI) ≤ 32 mL/m2/beat (AUC 0.67, 95% CI 0.54–0.78, p < 0.05) and global end-diastolic index (GEDI) < 583 mL/m2 (AUC 0.67, 95% CI 0.54–0.78, p < 0.05) after the initial fluid resuscitation are predictive for oliguria/anuria at 24 h after study inclusion. The combination of higher vasopressor dependency index (VDI, calculated as the (dobutamine dose × 1 + dopamine dose × 1 + norepinephrine dose × 100 + vasopressin × 100 + epinephrine × 100)/MAP) and norepinephrine, lower systemic vascular resistance index (SVRI), and mean arterial blood pressure (MAP) levels, in the setting of normal preload parameters, showed a more severe vasoplegia. Severe vasoplegia in the first 24 h of sepsis is associated with a higher risk of sepsis induced AKI. The SOFA and cardiovascular SOFA scores may identify patients at risk for sepsis AKI. Persistent low SVI and GEDI values after the initial fluid resuscitation may predict renal outcome.

Initial Hemodynamic Profiles of Children with Dengue Shock Syndrome in Referral Settings

Background: Fluid therapy for dengue shock syndrome (DSS) requires a dynamic approach that involves monitoring of the pathophysiological processes as well as the preload, contractility, and afterload assessment during the course dengue infection. Hemodynamically unstable DSS patients received in referral setting often complicated by fluid overload and secondary infection. Objective: This study aims to provide hemodynamic profiles and fluid responsiveness of pediatric patients admitted to the PICU with DSS. Methods: Hemodynamic profiles, laboratories, and demographic data were collected from patients aged 1 month to 18 years old with DSS who were admitted to the Pediatric Intensive Care Unit (PICU) at Dr. Sardjito General Hospital, Yogyakarta, Indonesia from January to December 2016. Hemodynamic profiles were assessed in clinically shock and not clinically shock group at PICU admission using the non-invasive Ultrasonic Cardiac Output Monitor (USCOM). Fluid responsiveness in clinically shock group was evaluated after fluid challenge with 10 ml/kgBW crystalloid or colloid. Results: Eighty six subjects were included in this study. Sixty six subjects were admitted to PICU with clinically shock condition. This group received less intravenous fluid than hemodynamically stable group (6.9 vs 7.52 ml/kgBW/hour respectively), had higher mean hematocrit level (42.09% vs 40.32% respectively), had higher hematocrit level during PICU stay (43.37% vs 42.06% respectively), significantly higher percentage to receive inotropes agent (62,1% vs 5%, p 0,000) and longer duration of inotropes usage (23,5 vs 0 hours, p 0.72). From the clinically shock patients admitted to PICU, only 19,69% were fluid responsive. Other subjects in this group with fluid non responsive state, 90,38% had low inotropic index and high systemic vascular resistance index. Among 8 patients in clinically shock group who died during PICU stay, 6 of them had low cardiac Index, fluid non responsive condition, low inotropic index and high systemic vascular resistance index. Conclusion: Only a small percentage of DSS patients with clinically shock admitted to the PICU were fluid responsive. Majority of DSS cases in children had low inotropy index and high systemic vascular resistance index.

Evolution of Acute Kidney Injury and Its Association With Systemic Hemodynamics in Children With Fluid-Refractory Septic Shock.

There are no studies in pediatrics evaluating the progression of acute kidney injury in septic shock. We investigated the evolution of sepsis-associated acute kidney injury and its association with systemic hemodynamics in children with fluid-refractory septic shock. Prospective cohort study. PICU of a tertiary care hospital. All patients with fluid-refractory septic shock (n = 61) between September 2010 and February 2014. Hemodynamic variables using noninvasive ultrasound cardiac output monitor were measured at admission and 6 hourly thereafter till 48 hours. We used the Kidney Disease: Improving Global Outcomes criteria to define and stage acute kidney injury. Associations between various hemodynamic variables and development of acute kidney injury were evaluated. Severe acute kidney injury was defined as stage 2 or 3 acute kidney injury and was compared with no acute kidney injury or stage 1 acute kidney injury. Severe acute kidney injury developed in 29.5% (n = 18) of the 61 children with fluid-refractory septic shock, whereas 43 patients (70.49%) had either no or stage 1 acute kidney injury. Most patients who developed acute kidney injury did so within the first 48 hours of PICU admission. Severe acute kidney injury conferred a three-fold increased risk of death by day 28 (hazard ratio, 3.23; 95% CI, 1.52-6.67; p = 0.002), longer ICU stay, and increased duration of mechanical ventilation. Central venous pressure at presentation was higher in severe acute kidney injury by 5 cm H2O. Highest lactate in the first 24 hours of PICU admission, low diastolic blood pressure, low systemic vascular resistance index at admission were associated with severe acute kidney injury. This model reliably predicted stage 2/3 acute kidney injury by day 3 with area under the curve equals to 94%; 95% CI, 88.3-99.99. None of the other hemodynamic variables showed any association with severe acute kidney injury. Manifestations of sepsis-associated acute kidney injury often occur early after PICU admission and is associated with increased morbidity and mortality. There is a need to develop a predictive model in septic shock which could facilitate early detection of acute kidney injury.

The use of bedside echocardiography for measuring cardiac index and systemic vascular resistance in pediatric patients with septic shock.

ObjectiveFollow-up of cardiac index and systemic vascular resistance index by bedside echocardiography until resuscitation.MethodsA set of hemodynamic parameters was obtained, including cardiac output, stroke volume, cardiac index, systemic vascular resistance index, velocity time integral, myocardial performance index, capillary refill time, and heart rate at 0 hours after fluid boluses before the start of inotropes, and followed up after 6 hours and 24 hours.ResultsIncluded were 45 patients with community-acquired septic shock. Septic foci were gastroenteritis (24%), intestinal perforation requiring emergency surgery (24%), pneumonia (20%), central nervous system infection (22%) and soft tissue infection (8%). Klebsiella and Enterobacter were the most frequent isolates. We estimated the factors affecting the cardiac index: high central venous pressure at zero time (r = 0.33, p = 0.024) and persistently high heart rate at hour 6 (r = 0.33, p = 0.03). The systemic vascular resistance index was high in most patients at 0 and 24 hours and at the time of resuscitation and inversely affected the cardiac index as well as affecting the velocity time integral (r = -0.416, -0.61, 0.55 and -0.295). Prolonged capillary refill time was a clinical predictor of the low velocity time integral at 24 hours (r = -0.4). The mortality was 27%. Lower systemic vascular resistance index and higher cardiac output were observed in nonsurviving patients.ConclusionThere was a persistently high systemic vascular resistance index in cold shock patients that influenced the stroke volume index, cardiac index, and velocity time integral. The use of echocardiograms for hemodynamic measurements is important in pediatric septic shock patients to adjust dilators, and vasopressor doses and achieve resuscitation targets in a timely manner.

Effect of Anemia on Cardiovascular Hemodynamics, Therapeutic Strategy and Clinical Outcomes in Patients With Heart Failure and Hemodynamic Congestion.

We investigated the effect of anemia on cardiovascular hemodynamics, therapeutic strategies and clinical outcomes in heart failure (HF) patients. We divided 198 consecutive HF patients who underwent right heart catheterization before in-hospital HF treatment into 2 groups according to the presence or absence of hemodynamic congestion (HC: mean pulmonary capillary wedge pressure ≥15 mmHg and/or mean right atrial pressure ≥10 mmHg). The hemoglobin level correlated with the cardiac index (CI) and systemic vascular resistance index (SVRI) (r=-0.34 and 0.42, P<0.05, respectively), and was the strongest contributor of SVRI only in the HC group. Anemic patients more frequently required intravenous inotropic support despite having higher CI and lower SVRI than non-anemic patients in the HC group. The novel hemodynamic subsets based on mean right atrial pressure and estimated left ventricular stroke work index but not Forrester subsets appropriately predicted the need for intravenous inotropic support. The probability of hospitalization for worsening HF during 2-year follow-up period was significantly higher in anemic patients than in non-anemic patients in the HC group. Anemia had a direct effect on cardiovascular hemodynamics and thus can confound therapeutic planning in HF patients with HC. The novel hemodynamic subsets can be applied in daily clinical practice regardless of the presence or absence of anemia.

Positive effects of aggressive vasodilator treatment of well-treated essential hypertensive patients.

Increased systemic vascular resistance and coronary microvascular dysfunction are well-documented in essential hypertension (EH). We investigated the effect of additional vasodilating treatment on coronary and peripheral resistance circulation in EH patients with high systemic vascular resistance index (SVRI) despite well-treated blood pressure (BP). We enroled patients on stable antihypertensive treatment that were given intensified vasodilating therapy (ACE inhibitor, angiotensin II receptor blocker or calcium channel blocker). Before and following 6 months of intensified therapy, coronary resting and maximal artery flow were measured by transthoracic Doppler echocardiography to calculate coronary flow reserve (CFR) and minimum vascular resistance (C-Rmin). Cardiac output was estimated by inert gas rebreathing to calculate SVRI. Maximal forearm blood flow was determined by venous occlusion plethysmography to calculate minimum vascular resistance (F-Rmin). Patients were assigned into two groups: high-SVRI and low-SVRI subgroups, based on a median split at baseline. Following additional treatment SVRI decreased more in the high-SVRI group than in the low-SVRI group (14.4 vs -2.2%: P=0.003), despite similar baseline ambulatory BP (132/81 mm Hg) and BP reduction (6.5 and 4.6%: P=0.19). F-Rmin remained unchanged (6.5 vs -2.0%: P=0.30), while C-Rmin decreased by 22 and 24% (P=0.80) and CFR increased by 23 and 17% (P=0.16). Thus, intensified vasodilating therapy improved SVRI more in patients with high SVRI than in those with low SVRI. Regardless of SVRI status, the treatment improved cardiac but not forearm dilatation capacity. The substantial improvement of the hypertensive cardiac microvascular dysfunction was not related to the reduction in SVRI.

A Randomized Blinded Study of the Left Ventricular Myocardial Performance Index Comparing Epinephrine to Levosimendan following Cardiopulmonary Bypass.

BackgroundThe objective was to evaluate the effect of epinephrine and levosimendan on the left ventricle myocardial performance index in patients undergoing on-pump coronary artery by-pass grafting (CABG).MethodsIn a double-blind, randomized clinical trial, 81 patients (age: 45–65 years) of both genders were randomly divided to receive either epinephrine at a dosage of 0.06 mcg.kg1.min-1 (epinephrine group, 39 patients) or levosimendan at 0.2 mcg.kg1.min-1 (levosimendan group, 42 patients) during the rewarming of cardiopulmonary by-pass (CPB). Hemodynamic data were collected 30 minutes after tracheal intubation, before chest open (pre-CPB) and 10 minutes after termination of protamine (post-CPB). As the primary outcome, we evaluated the left ventricle myocardial performance index by the Doppler echocardiography. The myocardial performance index is the sum of the isovolumetric contraction time and the isovolumetric relaxation time, divided by the ejection time. Secondary outcomes were systolic and diastolic evaluations of the left ventricle and postoperative troponin I and MB-CK levels.ResultsOf the 81 patients allocated to the research, we excluded 2 patients in the epinephrine group and 6 patients in the levosimendan group because they didn’t wean from CPB in the first attempt. There was no statistical difference between the groups in terms of patient characteristics, risk factors, or CPB time. The epinephrine group had a lower left ventricle myocardial performance index (p = 0.0013), higher cardiac index (p = 0.03), lower systemic vascular resistance index (p = 0.01), and higher heart rate (p = 0.04) than the levosimendan group at the post-CPB period. There were no differences between the groups in diastolic dysfunction. The epinephrine group showed higher incidence of weaning from CPB in the first attempt (95% vs 85%, p = 0.0001) when compared to the levosimendan group and the norepinephrine requirement was higher in the levosimenandan group than epinephrine group (16% vs. 47%; p = 0.005) in post-CPB period. Twenty-four hours after surgery, the plasma levels of troponin I (epinephrine group: 4.5 ± 5.7 vs. levosimendan group: 2.5 ± 3.2 g/dl; p = 0.09) and MB-CK (epinephrine group: 50.7 ± 31 vs. levosimendan group: 37 ± 17.6 g/dl; p = 0.08) were not significantly different between the two groups.ConclusionWhen compared to levosimendan, patients treated with epinephrine had a lower left ventricle myocardial performance index in the immediate post-CPB period, encouraging an efficient weaning from CPB in patients undergoing on-pump CABG.Trial RegistrationClinicalTrials.gov NCT01616069

Cardiovascular change in children with dengue shock syndrome.

To determine the cardiovascular changes in children with dengue shock syndrome. Echocardiography was performed in 8 children (5 females) with dengue shock syndrome, median age 6.5, 4.2-13.7 yr and weight 34, 12-66 kg. All had massive bleeding with low initial hematocrit in most cases (median 31%), thrombocytopenia (median platelet 37,000/μL), and coagulopathy with massive pleural effusion. Seven (87.5%) developed acute renal failure and hepatic failure. All patients were in either compensate or decompensate shock with alteration of consciousness, tachycardia, poor tissue perfusion, and prolonged capillary refill (>4 s) with mean arterial pressure 65, 39-94 mm Hg. The cardiac dimension was normal to low normal except one had dilated left ventricle. Seven patients had normal left ventricular systolic function (5 with inotrope infusion). One patient had impaired systolic function even with inotrope. All had normal cardiac index (4.14, 3.51-6.37 L/min/m2) with increased heart rate (141.5, 110-160/min) but low stroke volume index (30.72, 25.37-42.49 mL/m2) and low systemic vascular resistance index (1,072, 223-2,880 dyne/sec/cm-5/m2). Decreased preload from bleeding and vascular leakage into the third space play an important role in shock in Dengue. However, decreased stroke volume and low systemic vascular resistance may be additional causes of shock.

Impact of Aneurysm Location on Cardiopulmonary Dysfunction after Subarachnoid Hemorrhage

Cardiopulmonary dysfunction may occur after aneurysmal subarachnoid hemorrhage (SAH), but its characteristics have not been fully clarified. We investigated the impact of aneurysm location on systemic hemodynamics after SAH. This multicenter prospective cohort study measured hemodynamic parameters in relation to aneurysm location in patients with SAH using a single-indicator transpulmonary thermodilution system (PiCCO) on days 1-14. Of 204 subjects enrolled, 58 had aneurysms of the anterior communicating artery (ACA), 61 of the middle cerebral artery (MCA), 57 of the internal carotid artery (ICA), and 28 of the vertebrobasilar artery (VA/BA). Patient characteristics were similar except for predominance of coiling in the VA/BA. Patients with ACA aneurysm had a lower systemic vascular resistance index (SVRI) in the acute phase and afterload mismatch (lower cardiac index [CI] and higher SVRI) in the spasm phase. Those with ICA aneurysm had a lower CI in the acute phase, and those with VA/BA aneurysm had a warm shock-like condition (higher CI and lower SVRI) in the spasm phase. Patients with MCA aneurysm showed no specific characteristics in CI and SVRI with a significant improvement in B-type natriuretic peptide. Extravascular lung water index was high independent of left cardiac dysfunction. In multivariate analysis, age and ACA were independently related to poor global ejection fraction after SAH. Aneurysm location affects cardiac output, vascular resistance, and pulmonary edema in biphasic fashion. Patient age and location of aneurysm in the ACA may be risk factors for cardiac failure after SAH.

Hemodynamic Phenotype of the Failing Fontan in an Adult Population

Fontan failure can occur even with normal systolic ventricular function and often in the context of significant liver disease. We hypothesized that Fontan failure is hemodynamically distinct from traditional heart failure and characterized by low systemic vascular resistance (SVR) index and preserved cardiac index. Twenty-seven symptomatic adult Fontan (SAF) patients who underwent catheterization from 2001 to 2011 constituted our study group. Fifty-four predominantly asymptomatic pediatric Fontan (PF) patients who underwent catheterization during the same period were randomly selected to perform a control:case cohort analysis. Clinical comparisons were made between the 2 groups. The adults were more symptomatic than the PF cohort (New York Heart Association classes I and II or III and IV: 48% or 52% [SAF] vs 94% or 6% [PF], respectively, p <0.01). SAF versus PF mean catheterization findings were central venous pressure 18 ± 6 versus 14 ± 3mm Hg (p <0.01), SVR index 1,680 ± 368 versus 1,960 ± 550 dyn s/cm(5)/m(2) (p= 0.02), and cardiac index 2.7 ± 0.8 versus 2.8 ± 0.7L/min/m(2) (p= 0.25). By imaging, the SAF cohort demonstrated a greater incidence of abnormal liver texture changes (96% vs 75%, p= 0.04) and nodularity (77% vs 42%, p= 0.02). In conclusion, adult patients with failing Fontan circulation had a lower SVR index and similar cardiac index compared with the pediatric cohort. Liver disease in the adults was more advanced. Our data suggest that Fontan failure is a distinct circulatory derangement with hemodynamic features similar to portal hypertension, albeit with limited ability to augment cardiac output.

Systemic vascular resistance has an impact on the reliability of the Vigileo-FloTrac system in measuring cardiac output and tracking cardiac output changes

BackgroundThe aim of this study was to examine the ability of the Vigileo-FloTrac system to measure cardiac output (CO) and track changes in CO induced by increased vasomotor tone, under different states of systemic vascular resistance (SVR). MethodsForty patients undergoing cardiac surgery were enrolled. Haemodynamic variables including CO measured by the Vigileo-FloTrac system (version 3.02) (APCO), CO measured by a pulmonary artery catheter (ICO), and SVR index (SVRI) were recorded before (T1) and 2 min after (T2) phenylephrine administration (100 μg). Bland and Altman analysis was used to compare ICO and APCO at T1. We used four-quadrant plots and polar plots to compare the trending abilities between ICO and APCO. Patients were divided into three groups according to the SVRI value at T1, with low (<1200 dyn cm−5 m2), normal (1200–2500 dyn cm−5 m2), and high (>2500 dyn cm−5 m2) SVRI states. ResultsA total of 155 paired data were collected. The adjusted percentage error was 46.3%, 26.4%, and 61.4%, and the concordance rate between ΔICO and ΔAPCO was 67.5%, 28.8%, and 7.7% in the low, normal, and high SVRI state, respectively. The polar plot analysis showed that the mean angular bias was −22.3°, −46.0°, and −3.51°, and the radial limits of agreement were 70°, 85°, and 87°, in the low, normal, and high SVRI state, respectively. ConclusionsThese results indicate that the reliability of the Vigileo-FloTrac system to measure CO and track changes in CO induced by phenylephrine administration was not clinically acceptable.

401 Cardiovascular Indices Measured by a Noninvasive Doppler Ultrasonography Cardiac Output Monitor in Patients With Stage 2 Hypertension

Study Objective: Hypertensive patients either have increased systemic vascular resistance or increased cardiac output, or both. The exact prevalence of these pathophysiological derangements, and their relative contribution to hypertension, are not known. Study Objectives: To use a noninvasive Doppler ultrasonography cardiac output monitor to measure haemodynamic parameters and determine the relative derangements of cardiac output and systemic vascular resistance in emergency department patients with Stage 2 hypertension. Methods: Patients aged 18 years or above who attended the emergency department (ED) with systolic blood pressure> 160 or diastolic blood pressure >100 in 2 or more measurements at least 20 minutes apart were included. Research assistants collected demographic and clinical data and measured the cardiac output and systemic vascular resistance of these patients with a noninvasive Doppler ultrasonography cardiac output monitor. Patients were followed up within 2 weeks. Those who did not have documented increased blood pressure (Stage 2) in 2 or more different occasions were excluded. The patients' body surface area (BSA) was calculated to obtain the cardiac index (CI) and the systemic vascular resistance index (SVRI); where CI = cardiac output/BSA and SVRI = systemic vascular resistance/BSA. Results: Forty-nine patients were included. Mean age (+/− SD) was 66.5 +/− 12.5 years and 59.2% were females. 7 (14.3%) had either high cardiac output or high CI; 41(83.7%) had either high systemic vascular resistance or high SVRI; one had normal haemodynamics; 18 (36.7%) had either low cardiac output or low CI; and 3 (6.1%) had low SVRI. The prevalence of haemodynamic derangement subtypes was as follows: 4 (8.2%) with systemic vascular resistance normal, cardiac output high; 39 (79.5%) with systemic vascular resistance high, cardiac output normal; 4 (8.2%) with systemic vascular resistance and cardiac output normal; 2 (4.1%) with systemic vascular resistance high, cardiac output low. Conclusion: In ED patients with Stage 2 hypertension, about 80% have increased systemic vascular resistance. If clinicians choose anti-hypertensive therapy aiming at reducing systemic vascular resistance, it may result in a much higher likelihood of effective blood pressure control.

Comparison of Sympathomimetics in the Correction of Arterial Hypotension during Combined Anesthesia

Objective: to make a comparative assessment of hemodynamic parameters when correcting combined anesthesia-induced arterial hypotension with dopamine, adrenaline, mesatone, or noradrenaline. Subjects and methods. A prospective study enrolled patients who had undergone prosthetic hip replacement under combined lumbar epidural (ropivacaine)/general (sevoflurane) anesthesia. Intravenous sympathomimetic infusion was initiated when the mean blood pressure decreased below 55 Hg mm. Cardiac index (CI) and systemic vascular resistance index (SVRI) were calculated by impedance cardiography. Fifty-six subjects (14 in each group) were selected for analysis. Results. During the study, CI remained in the normal range for all sympathomimetics. When adrenaline was administered, there was an obvious tendency to maintain blood pressure due to heart rate (HR) with preserved low SVRI. The use of mesatone caused a considerable reduction in HR. No statistically significant differences were found between the dopamine and noradrenaline groups in any of the study stages. The start of infusion of these agents was attended by SVRI normalization and HR maintenance within 60—70 beats per minute. Conclusion. The infusion of dopamine, adrenaline, mesatone, or noradrenaline to correct arterial hypotension resulting from combined epidural block/general anesthesia with sevoflurane ensures maintenance of CI within the normal range. That of noradrenaline and dopamine was ascertained to have a more balanced impact on HR and systemic vascular resistance. Key words: combined anesthesia, epidural block, hemodynamics, sympathomimetics, adrenaline, dopamine, mesatone, noradrenaline.