Cessation Of Cardiopulmonary Bypass Research Articles

Histidine-trytophan-ketoglutarate cardioplegia reduces inflammatory response and serum levels of myocardial enzymes in newly developed right-thoracotomy rat model

The objective of this research was to establish a rat model for cardiopulmonary bypass (CPB) with cardiac arrest and resuscitation that is both practical and economical and simulates clinical cardiac surgery. Concurrently, the study aimed to evaluate the myocardial protective effects conferred by histidine–tryptophan–ketoglutarate (HTK) cardioplegia. Thirty rats were randomly assigned to three groups: the histidine–tryptophan–ketoglutarate (HTK), 4:1 blood cardioplegia (BC) and del Nido cardioplegia (DN) groups. The cardiopulmonary bypass (CPB) procedure was implemented and sustained for a duration of one hour. Subsequent to the cessation of CPB, the rats were subjected to monitoring and observation for an additional two hours. Following this observation period, the heart and blood samples were procured for subsequent analysis. During CPB, the average hematocrit level was significantly below the typical physiological range (P < 0.001). Histopathological scores were notably lower in the HTK group in contrast to the BC group (P < 0.001) or the DN group (P < 0.001). At 2 h after weaning off CPB, the levels of CK and CKMB in the DN and BC groups were notably elevated compared to the HTK group (P < 0.001). The levels of IL-6 and TNF-α proteins were notably increased in all three groups (P < 0.001), with the BC and DN groups showing higher increases compared to the HTK group (P < 0.001). This compact animal model of cardiopulmonary bypass (CPB) with cardiac arrest and resuscitation might allow for both the study of myocardial ischemia-reperfusion injury as well as cardioprotective strategies. HTK cardioplegia could reduce inflammatory response and serum levels of myocardial enzymes in this newly developed right thoracotomy rat model.

Urine dipstick blood and acute kidney injury in infants undergoing cardiopulmonary bypass.

Cardiopulmonary bypass (CPB) is associated with hemolysis and acute kidney injury (AKI). The study aim was to determine if urine dipstick blood in infants after CPB was associated with AKI and urine neutrophil gelatinase-associated lipocalin (NGAL). Infants who underwent CPB at a single center were enrolled prospectively between October 2017 and June 2019. Urine samples prior to CPB and 6h after CPB cessation were analyzed in batch for NGAL and dipstick blood. AKI was defined using creatinine-based KDIGO criteria within 72h of CPB. Spearman correlation examined associations between urine dipstick blood and NGAL at each time point. Linear regression estimated the associations between urine dipstick blood and log-transformed NGAL 6h after CPB. Logistic regression estimated associations and compared discrimination between urine dipstick blood and NGAL for predicting AKI. At baseline, 7/63 samples (11%) had > trace blood. Six hours after CPB, 62/98 samples (63%) had > trace blood and 26% had 3 + (large) blood. In total, 18/98 (18%) with a 6-h post-CPB sample had postoperative AKI. Urine dipstick blood values correlated with urine NGAL 6h after CPB (r = 0.52, p < 0.01), but not at baseline (r = 0.06, p = 0.66). Those with 3 + (large) blood on urine dipstick had 6 times higher mean NGAL values compared to those with negative/trace blood (mean ratio 6.6, 95%CI 3.1-14.4, p < 0.01). Those with 3 + (large) blood had 8 times higher odds of AKI (OR 7.99, 95%CI 1.5-41.9, p = 0.01). Urine dipstick blood post CPB may be a simple and inexpensive tool to help predict AKI in infants.

Hemolysis Precedes Urine Color Change in Patients Undergoing Open-Heart Surgery on Cardiopulmonary Bypass.

Red-colored urine often occurs in patients in the perioperative period who undergo cardiac surgery using cardiopulmonary bypass (CPB). This urine color change has been utilized for approximating hemolysis during CPB without a proven relationship for ongoing hemolysis. This case series study aimed to examine the relationship between plasma free hemoglobin (Hb) levels and quantified measures of urine color. Ten patients were enrolled in this study. Blood and urine were collected for analyses for the following time points: before surgery, two hours after the initiation of CPB, every 30 min during CPB thereafter, and 0, 2, 4, 12, and 24 hours after the completion of CPB. We measured free Hb in plasma and urine using the azide-methemoglobin method. Photographs of urine were obtained, and the luminance of the three basic colors (red/green/blue) was analyzed by quantitative luminance contrast analysis to find a correlation for hemolysis. Median levels of plasma free Hb were 0.015 (0.010-0.080, n = 10) g/dL at baseline. During the CPB, increases in plasma free Hb levels were measured: median plasma free Hb levels were increased to0.100 g/dL(0.020-0.240, p = 0.039, vs. baseline, n = 9) at two hours into CPB, median and range, respectively.In contrast, increases in urinary free Hb levels and/or urine color changes were measured only after cessation of CPB in nine patients. Urine color change or elevation of urinary free Hb levels followed the elevation of plasma free Hb levels with considerable delay.

Multimodal measurement of glycocalyx degradation during coronary artery bypass grafting.

Glycocalyx shedding and subsequent endothelial dysfunction occur in many conditions, such as in sepsis, in critical illness, and during major surgery such as in coronary artery bypass grafting (CABG) where it has been shown to associate with organ dysfunction. Hitherto, there is no consensus about the golden standard in measuring glycocalyx properties in humans. The objective of this study was to compare different indices of glycocalyx shedding and dysfunction. To this end, we studied patients undergoing elective CABG surgery, which is a known cause of glycocalyx shedding. Sublingual glycocalyx thickness was measured in 23 patients by: 1) determining the perfused boundary region (PBR)-an inverse measure of glycocalyx thickness-by means of sidestream dark field imaging technique. This is stated double, 2) measuring plasma levels of the glycocalyx shedding products syndecan-1, hyaluronan, and heparan sulfate and 3) measuring plasma markers of impaired glycocalyx function and endothelial activation (Ang-2, Tie-2, E-selectin, and thrombomodulin). Measurements were performed directly after induction, directly after onset of cardiopulmonary bypass (CPB), and directly after cessation of CPB. We assessed changes over time as well as correlations between the various markers. The PBR increased from 1.81 ± 0.21 μm after induction of anesthesia to 2.27 ± 0.25 μm (p < 0.0001) directly after CPB was initiated and did not change further during CPB. A similar pattern was seen for syndecan-1, hyaluronan, heparan sulfate, Ang-2, Tie-2, and thrombomodulin. E-selectin levels also increased between induction and the start of CPB and increased further during CPB. The PBR correlated moderately with heparan sulfate, E-selectin, and thrombomodulin and weakly with Syndecan-1, hyaluronan, and Tie-2. Shedding markers syndecan-1 and hyaluronan correlated with all functional markers. Shedding marker heparan sulfate only correlated with Tie-2, thrombomodulin, and E-selectin. Thrombomodulin correlated with all shedding markers. Our results show that glycocalyx thinning, illustrated by increased sublingual PBR and increased levels of shedding markers, is paralleled with impaired glycocalyx function and increased endothelial activation in CABG surgery with CPB. As correlations between different markers were limited, no single marker could be identified to represent the glycocalyx in its full complexity.

Utility of plasma NGAL for the diagnosis of AKI following cardiac surgery requiring cardiopulmonary bypass: a systematic review and meta-analysis

The objective of this study was to assess the diagnostic value of plasma neutrophil gelatinase-associated lipocalin (pNGAL) for the early diagnosis of acute kidney injury (AKI) in adult patients following cardiac surgery requiring cardiopulmonary bypass (CPB). Electronic databases and other resources were systematically searched for relevant studies. Risk of bias was assessed using the Quality Assessment for Diagnostic Accuracy Studies 2 (QUADAS-2) tool. Studies were assigned to a sub-group based on the timing of the pNGAL sample in relation to the cessation of CPB. These were < 4 h, 4–8 h, 12 h or 24 h post-cessation of CPB. Summary values for sensitivity and specificity were estimated using the hierarchical summary receiver operator characteristic (ROC) curve model. A random-effects meta-analysis of each pair of sensitivity and specificity estimates from each included study was performed. In total, 3131 patients from 16 studies were included. When taken at 4–8 h following CPB, pNGAL had superior performance for the diagnosis of AKI in the defined population when compared to earlier and later time points. Prediction regions and confidence intervals, however, demonstrated significant variability in pooled estimates of sensitivity and specificity. This is likely due to population and study design heterogeneity, lack of standardisation of assays and thresholds, and inability to distinguish the different molecular forms of NGAL. In conclusion, the diagnostic utility of pNGAL in this clinical setting is inconclusive and large individual studies of representative populations of cardiac surgery patients using assays that specifically detect NGAL in its monomeric form are required.

Association of hemolysis with the incidence of heart rhythm disturbances following coronary artery bypass graft surgery

Introduction: Coronary artery bypass grafting (CABG) might be associated with the development of heart rhythm disturbances. We aimed at evaluating an association of intraoperative hemolysis (IOH) with the development of cardiac rhythm disturbances in patients with coronary artery disease after on-pump CABG.Methods. The assessment of the degree of IOH was performed according to the level of plasma free hemoglobin [Hb] at baseline, immediately after the patient was connected to the cardiopulmonary bypass (CPB) device and 15 minutes before cessation of CPB. We included 123 patients, and they were divided into 3 groups (gr.) according to free [Hb] level: gr.1 - ≤0.1 g/l; gr.2 - &gt; 0.1 g/l and &lt;0,5 g/l; gr.3 - ≥0.5 g/l. A variety of ECG screening methods were applied for the detection of cardiac arrhythmia in the postoperative period. The follow-up period was 1 months.Results. Arrhythmias were observed in 2.3% of patients in the 1st group, in 11.9% in the 2nd group, and in 52.6% in the 3rd group. The level of plasma free [Hb] in samples taken at the end of CPB was strongly associated with the arrhythmia detection (rs=0,70, p &lt;0.001). Life-threatening and hemodynamically unstable arrhythmias were more frequently detected in the group with a higher degree of IOH (p &lt;0.001), and accounted for about half of all arrhythmias.Conclusions. On-pump CABG is associated with the development of cardiac arrhythmias in the postoperative period in 22% of patients. A significant proportion of these arrhythmias are potentially life-threatening. The highest proportion of patients with cardiac rhythm disturbances after CABG was observed when the level of plasma free hemoglobin was &gt;0.5 g.

Abstract 15823: Diminished Vasoresponsiveness in Patients With Heart Failure

Introduction: Vasoplegia is a severe complication after cardiac surgery and is associated with impaired clinical outcome. Pre-operative heart failure (HF) is considered an independent predictor of post-operative vasoplegia. We hypothesize that HF patients are more susceptible to vasoplegia due to altered vascular responsiveness. In this study, vasoresponsiveness in patients undergoing cardiac surgery for HF is investigated. Methods: A prospective, observational study was conducted at Leiden University Medical Center. We included patients with HF (N=18) and without HF (N=18) who underwent cardiac surgery on cardiopulmonary bypass. Vasoresponsiveness was assessed at 4 different timepoints: 1) before induction, 2) after induction, 3) after cessation of cardiopulmonary bypass and 4) on the first postoperative day. The vascular response was recorded as change in systemic vascular resistance (SVR) after the administration of phenylephrine (bolus 2 μg/kg). Results: Thirty-six patients were included [67 (61-71) years, 78% male]. Vascular responsiveness was significantly attenuated in patients with HF compared to controls. The response to phenylephrine was already diminished at baseline in HF patients and was almost abolished after cessation of cardiopulmonary bypass (Figure). Roughly the same pattern of vasoresponsiveness was found when excluding patients that received norepinephrine. Moreover, HF patients required a significantly higher amount of noradrenaline [169.80 (IQR 14.77-318.97) ug/kg] compared to controls [3.61 (IQR 0-41.60) ug/kg] to maintain similar SVR during the first 24h postoperatively. Conclusions: The vascular responsiveness is altered in patients with HF and this might explain the higher prevalence of vasoplegia in this patient population.

Are We Able to Dose Protamine Accurately Yet? A Review of the Protamine Conundrum

Without anticoagulation, cardiopulmonary bypass would not have developed over the last nearly 60 years into one of the most influential innovations in medicine; without the ability to reverse anticoagulation, cardiac surgery might not have become the common intervention, which is now practiced globally. Despite the recent breathtaking developments in extracorporeal technology, heparin and protamine remain the pillars of anticoagulation and its reversal until this day. However, there is still much controversy in particular about protamine dosing regimens. A number of recent publications investigating various approaches to dosing protamine have rekindled this debate. This review is seeking to capture the current thinking about protamine dosing after cessation of cardiopulmonary bypass.

Vasoresponsiveness in patients with heart failure (VASOR): protocol for a prospective observational study

BackgroundVasoplegia is a severe complication which may occur after cardiac surgery, particularly in patients with heart failure. It is a result of activation of vasodilator pathways, inactivation of vasoconstrictor pathways and the resistance to vasopressors. However, the precise etiology remains unclear. The aim of the Vasoresponsiveness in patients with heart failure (VASOR) study is to objectify and characterize the altered vasoresponsiveness in patients with heart failure, before, during and after heart failure surgery and to identify the etiological factors involved.MethodsThis is a prospective, observational study conducted at Leiden University Medical Center. Patients with and patients without heart failure undergoing cardiac surgery on cardiopulmonary bypass are enrolled. The study is divided in two inclusion phases. During phase 1, 18 patients with and 18 patients without heart failure are enrolled. The vascular reactivity in response to a vasoconstrictor (phenylephrine) and a vasodilator (nitroglycerin) is assessed in vivo on different timepoints. The response to phenylephrine is assessed on t1 (before induction), t2 (before induction, after start of cardiotropic drugs and/or vasopressors), t3 (after induction), t4 (15 min after cessation of cardiopulmonary bypass) and t5 (1 day post-operatively). The response to nitroglycerin is assessed on t1 and t5. Furthermore, a sample of pre-pericardial fat tissue, containing resistance arteries, is collected intraoperatively. The ex vivo vascular reactivity is assessed by constructing concentrations response curves to various vasoactive substances using isolated resistance arteries. Next, expression of signaling proteins and receptors is assessed using immunohistochemistry and mRNA analysis. Furthermore, the groups are compared with respect to levels of organic compounds that can influence the cardiovascular system (e.g. copeptin, (nor)epinephrine, ANP, BNP, NTproBNP, angiotensin II, cortisol, aldosterone, renin and VMA levels). During inclusion phase 2, only the ex vivo vascular reactivity test is performed in patients with (N = 12) and without heart failure (N = 12).DiscussionUnderstanding the difference in vascular responsiveness between patients with and without heart failure in detail, might yield therapeutic options or development of preventive strategies for vasoplegia, leading to safer surgical interventions and improvement in outcome.Trial registrationThe Netherlands Trial Register (NTR), NTR5647. Registered 26 January 2016.

Effect of oxygen content on postoperative cognitive dysfunction in patients undergoing open-heart surgery

Introduction: Brain's decreased oxygen delivery is proposed as a risk factor for postoperative cognitive dysfunction (POCD). This study's objective was to investigate the effect of arterial oxygen content (CaO2) on POCD in patients undergoing open-heart surgery. Subjects and Methods: Adult patients listed for elective open-heart surgery at Cipto Mangunkusumo General Hospital were enrolled. The patients' cognitive function was tested using the Rey Auditory Verbal Learning Test, trail-making test, and digit span test (forward–backward) before and 5 days after surgery. The hemoglobin level, arterial saturation (SaO2), and arterial oxygen partial pressure (PaO2) were measured at the following five time points: before induction, 10 min after the commencement of cardiopulmonary bypass (CPB), 10 min after the cessation of CPB, 6 h postoperatively, and 1 day postoperatively. The CaO2 was calculated as follows: CaO2= 1.36 × hemoglobin × SaO2 + 0.003 × PaO2. Data were compared using Student's t-test or the Mann–Whitney test with SPSS software version 20.0 (IBM Corp., Armonk, NY, USA). Results: POCD was found in nine patients (47.4%). The CaO was significantly lower in patients with POCD than those without POCD at 10 min after the cessation of CPB (12.1 ± 2.6 vs. 14.5 ± 1.7, respectively; P = 0.03). The hemoglobin level appeared to be the cause of the decreased CaO2 in the POCD group (8.5 ± 2.3 vs. 10.2 ± 1.2, P = 0.06). Decreased oxygen content after CPB cessation may impair brain tissue oxygenation that causes POCD. Conclusion: Hemoglobin level may play an important role in POCD development after open-heart surgery.

Thyroid Hormone (Triiodothyronine) Therapy in Children After Congenital Heart Surgery: A Meta-Analysis

Thyroid hormone modifies metabolic, immune and cardiovascular functions and has been administered perioperatively to treat a relative reduction of thyroid function in children following cardiopulmonary bypass (CPB) for correction of congenital heart disease. However, it remains unclear whether its use is associated with improved outcomes. We performed a meta-analysis of studies that evaluated the impact of thyroid hormone supplementation on clinical outcomes in children undergoing repair of congenital heart disease using CPB. A systematic review of published trials was conducted to identify studies of children randomized to thyroid hormone supplementation or placebo undergoing congenital heart surgery. A meta-analysis was then conducted to determine the clinical impact of thyroid hormone replacement on cardiac function and postoperative characteristics. The following outcomes were included for the study: duration of mechanical ventilation, duration of intensive care unit (ICU) stay, duration of postoperative hospital stay, inotrope score, cardiac index at 24 hours postoperatively, and inpatient mortality. A total of 9 studies with 711 patients were included in the analyses. All included studies were prospective and patients were randomized to either thyroid hormone or placebo. There was wide variation in thyroid hormone dosing, ranging from 0.4 μg/kg up to 5 μg/kg over a 24-hour period, and duration of therapy, ranging from a single dose after cessation of CPB to continued thyroid hormone for the duration of the ICU stay. There was a significant difference in the mean inotrope score between the 2 groups of -1.249 (95% confidence interval -1.570 to -0.929, P < 0.001), with the inotrope score being significantly lower in the thyroid group. There was no difference in duration of mechanical ventilation, duration of ICU stay, duration of hospital stay, cardiac index, and mortality between groups. In this meta-analysis, routine thyroid hormone replacement with approximately 1-5 μg/kg administered over 24 hours does not significantly alter the postoperative course in children following CPB. However, given a clinically small but significant difference in respect to lower inotrope score and shorter duration of ICU and hospital stays with higher thyroid replacement additional studies are warranted.

Effect of Autotransfusion Using Intraoperative Predonated Autologous Blood on Coagulopathy during Thoracic Aortic Surgery: A Randomized Controlled Trial.

Background: Intraoperative predonated autologous blood transfusion is thought to replenish platelets and coagulation factors and ameliorate coagulopathy. This study aimed to evaluate whether intraoperative predonated autotransfusion improves coagulopathy during thoracic aortic surgery.Methods: Patients who underwent thoracic aortic surgery were randomized into two groups as follows: those who received intraoperative predonated blood (group A: n = 31) and those who did not receive (group N: n = 22). In group A, autologous blood was retransfused immediately after cessation of cardiopulmonary bypass (c-CPB).Results: The mean intraoperative allogenic blood or blood product transfusion requirements were significantly lesser in group A than in group N (packed red blood cells [RBCs]: 6.3 ± 5.1 vs. 9.1 ± 4.3 units, p = 0.04; fresh frozen plasma [FFP]: 3.0 ± 4.1 vs. 6.1 ± 5.7 units, p = 0.03). After c-CPB, hemoglobin (Hb) level, platelet count, and coagulopathy became significantly worse than those at the start of surgery in both the groups. However, the values significantly improved 30 min after c-CPB only in group A. Renal function was significantly worse in group N.Conclusions: Intraoperative predonated autotransfusion significantly improved coagulopathy, with reduced allogeneic blood transfusion volume during thoracic aortic surgery. Furthermore, reduction of allogeneic blood transfusion may reduce the adverse effects on renal function.

Correlating Oxygen Delivery During Cardiopulmonary Bypass With the Neurologic Injury Biomarker Ubiquitin C-Terminal Hydrolase L1 (UCH-L1)

The authors sought to assess the relationship between low oxygen delivery (DO2) during cardiopulmonary bypass (CPB) and a neuron-specific biomarker of neurologic injury, ubiquitin C-terminal hydrolase L1 (UCH-L1). Retrospective analysis of patient charts and prospectively collected blood samples. University-affiliated tertiary care hospital. Adult patients undergoing cardiac surgery on CPB. Serum UCH-L1 levels were drawn at baseline and 6 and 24 hours after CPB cessation. DO2 was computed from perfusion records, with area-under-the-curve (AUC) computations performed to account for distance of DO2 excursions below predefined DO2 thresholds and the amount of time spent below them. Strokes were defined radiographically using computed tomography and magnetic resonance imaging. Forty-three adults were included (median age 65 y, interquartile range 59-72). Three patients experienced strokes (imaged at 2, 7, and 8 d postoperatively). Most patients underwent isolated coronary artery bypass grafting (41%, 18 patients) or isolated aortic valve replacement (30%, 13). Median UCH-L1 levels differed from baseline to 6 and 24 hours after CPB (40, 232, and 166 pg/mL, respectively; p < 0.001). On multivariable linear regression analysis controlling for baseline and surgical variables, only DO2 AUC <225 was significantly associated with 6-hour UCH-L1 levels (p = 0.001), whereas only DO2 AUC <300 was significantly associated with 24- hour levels (p < 0.001). The 3 patients who experienced radiographic strokes had nonsignificantly elevated 24-hour UCH-L1 levels compared with control patients (585 v 151 pg/mL, p = 0.11). This is the first study to demonstrate an independent association between DO2 during CPB and elevations of a brain injury biomarker; additional study is needed to clarify the clinical significance of these results.

Association Between Optic Nerve Head Blood Flow Measured Using Laser Speckle Flowgraphy and Radial Arterial Pressure During Aortic Arch Surgery

This study was designed to investigate the association between ocular blood flow measured using laser speckle flowgraphy (LSFG) and radial arterial pressure during aortic arch surgery. A prospective study. A single university hospital. This study included 24 patients undergoing aortic arch surgery with cardiopulmonary bypass (CPB) using antegrade selective cerebral perfusion (SCP). Measurement of optic nerve head blood flow using LSFG and radial arterial pressure via a catheter in the radial artery METHODS AND MAIN RESULTS: Antegrade SCP was managed with 24℃ and 40-to-60 mmHg at the right radial artery, which usually corresponds to a flow rate of 10 mL/kg/min. Optic nerve head blood flow using LSFG and radial arterial blood pressure were evaluated simultaneously at the right side and recorded at the following 4 points: after the induction of anesthesia (phase 1), after the beginning of CPB (phase 2), after the beginning of antegrade SCP (phase 3), and after cessation of CPB (phase 4). A moderate positive correlation between %change of mean blur rate in the optic nerve head measured using LSFG and %change of radial mean arterial pressure was identified (r = 0.604, p < 0.001). Bland-Altman analysis showed that the bias (mean difference) was -1.2% (95% limits of agreement -47.4% to 45.0%), indicating good agreement between %changes of the values recorded using the 2 measurements. Intraoperative monitoring of optic nerve head blood flow using LSFG can be used as an additional cerebral perfusion parameter during aortic arch surgery with CPB using antegrade SCP.

Intraoperative arrhythmias in children with congenital heart disease: transient, innocent events?

The significance and incidences of intraoperative arrhythmias occurring in the operating room (OR) in children with congenital heart disease (CHD) are unknown. Aims of this study were to determine incidences of intraoperative arrhythmias in children with CHD and to examine whether they are associated with persistent arrhythmias during follow-up. Continuous ECG recordings obtained from 134 consecutive paediatric CHD patients were manually examined from the moment the aortic cross-clamp (ACC) was removed [use of ACC and cardiopulmonary bypass (CPB)], when CPB was stopped (use of only CPB) or when the sternum was closed (no use of ACC and CPB) until departure from the OR. In the OR, 2nd (60%) and 3rd (34%) degree atrioventricular conduction block (AVB), ectopic atrial rhythm (30%), and junctional rhythm (32%) were most often observed in patients who underwent surgery with both ACC and CPB. Incidences of these arrhythmias decreased after cessation of CPB (P < 0.01). (Supra)ventricular premature beats were mostly observed between end of ACC time and sternum closure (64-84%), but decreased before departure from the OR (6-16%, P < 0.01). During a median follow-up of 37 months, 17 patients (13%) had new onset, late post-operative arrhythmias. Of these patients, 88% had intraoperative arrhythmias compared with 85% of patients without late post-operative arrhythmias (P = 1). Intraoperative arrhythmias, mainly 2nd degree AVB and (supra)ventricular premature beats, were frequently observed in children with CHD undergoing cardiac surgery with use of CPB and ACC. Most arrhythmias were short-lasting and transient and appeared not to be related to late post-operative arrhythmias.

Dynamic Cerebral Autoregulation after Cardiopulmonary Bypass.

Background Cerebral hemodynamic disturbances in the peri- or postoperative period may contribute to postoperative cognitive dysfunction (POCD) in patients undergoing coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB). We therefore examined dynamic cerebral autoregulation (dCA) post-CPB and changes in neurocognitive function in patients that had undergone CABG. Materials and Methods We assessed dCA by transfer function analysis of spontaneous oscillations between arterial blood pressure and middle cerebral artery blood flow velocity measured by transcranial Doppler ultrasound in eight patients 6 hours after the cessation of CPB; 10 healthy volunteers served as controls. Neurocognitive function was assessed by four specific tests 1 day prior to and 3 days after CPB. Results Even though patients exhibited systemic inflammation and anemic hypoxemia, dCA was similar to healthy volunteers (gain: 1.24 [0.94-1.49] vs. 1.22 [1.06-1.34] cm mm Hg-1 s-1, p = 0.97; phase: 0.33 [0.15-0.56] vs. 0.69 [0.50-0.77] rad, p = 0.09). Neurocognitive testing showed a perioperative decline in the Letter Digit Coding Score (p = 0.04), while weaker dCA was associated with a lower Stroop Color Word Test (rho = - 0.90; p = 0.01). Discussion and Conclusion We found no changes in dCA 6 hours after CPB. However, based on the data at hand, it cannot be ruled out that changes in dCA predispose to POCD, which calls for larger studies that assess the potential impact of dCA in the early postoperative period on POCD.

Cardiovascular effects of prolonged milrinone inhalation in patients with pulmonary hypertension undergoing mitral valve replacement

Context Inhaled milrinone has short-acting selective pulmonary vasodilator effect. Aims The aim of the study was to investigate the cardiovascular effects of prolonged inhalation of nebulized milrinone on patients with pulmonary hypertension undergoing mitral valve replacement. Settings and design This is a controlled, randomized, double-blinded study. Patients and methods Forty patients were divided into two groups: the milrinone group and the control group. The milrinone group received milrinone nebulization before cardiopulmonary bypass (CPB) as the loading dose at 50 mg/kg, followed by a maintenance dose of 0.5 mg/kg/min, which was continued for 2 h after tracheal extubation. The control group received an equivalent volume of 0.9% sodium chloride. The measured and calculated variables included heart rate, mean arterial blood pressure, central venous pressure, mean pulmonary artery pressure (mPAP), pulmonary capillary wedge pressure, cardiac index (CI), pulmonary vascular resistance (PVR), and systemic vascular resistance. The time points of measurements and calculations were as follows: at T 0 - after anesthesia induction and before sternotomy; at T 1 - 20 min after CPB cessation; at T 2 - 1 h after CPB cessation; at T 3 - 3 h after CPB cessation; at T 4 - 1 h after tracheal extubation; and at T 5 - 1 h after milrinone discontinuation. The duration of CPB and time of tracheal extubation were recorded. Results The milrinone group showed significant reduction in mPAP (T 2 to T 4 readings), pulmonary capillary wedge pressure (T 3 reading), and PVR (T 2 to T 4 readings), increase in CI (T 3 and T 4 readings), and shorter CPB duration and tracheal extubation time. Conclusion Prolonged inhalation of nebulized milrinone proved to be feasible in patients with pulmonary hypertension (PAH) undergoing mitral valve replacement. It decreased PVR and mPAP while increasing CI. This helped shorter CPB duration and earlier tracheal extubation.

Effect of Timing and Route of Methylprednisolone Administration During Pediatric Cardiac Surgical Procedures

We compared the antiinflammatory and cardioprotective effects of the two most common regimens of corticosteroid administration in pediatric cardiac surgical procedures: a single dose delivered either at anesthesia induction or by cardiopulmonary bypass (CPB) prime. Forty-five children, aged between 1 and 18 months and undergoing ventricular septal or atrioventricular septal defect correction, were randomized in double-blind fashion into three groups. The anesthesia induction group received 30 mg/kg methylprednisolone intravenously after anesthesia induction, and the CPB-prime group received 30 mg/kg methylprednisolone by CPB circuit. The placebo group received saline solution. Plasma concentrations of methylprednisolone, interleukin (IL)-6, IL-8 and IL-10, and troponin were measured at anesthesia induction before the study drug, 30 minutes on CPB, after patients were weaned from CPB, and 6 hours after cessation of CPB. Equally high methylprednisolone concentrations were detected in both methylprednisolone groups, but the measured peak concentration occurred earlier in the induction group. Significantly lower IL-8 concentrations were observed just after patients were weaned from and 6 hours after CPB in the anesthesia induction group compared with the placebo (p = 0.002, p = 0.001) and prime groups (p = 0.003, p = 0.006). Significant reductions of troponin were detected in both methylprednisolone groups compared with placebo (induction, p = 0.001; prime, p = 0.002) 6 hours after patients were weaned from CPB. Methylprednisolone administration at anesthesia induction was superior in terms of antiinflammatory action. Methylprednisolone administration in CPB-prime only a few minutes before aortic cross-clamping and cardioplegia resulted in mean troponin reductions similar to those of administration at anesthesia induction. Corticosteroids may have direct cardioprotective properties, as reported in experimental studies.

Effect of preoperative angiotensin-converting enzyme inhibitor and angiotensin II receptor blocker use on hemodynamic variables in pediatric patients undergoing cardiopulmonary bypass.

Some have suggested that children undergoing cardiac surgery who receive angiotensin-converting enzyme (ACE) inhibitors experience a greater degree of hypotension after anesthesia induction and in the immediate postcardiopulmonary bypass period than children who did not receive these drugs. Therefore, we examined the effect of ACE inhibitor/angiotensin II receptor blocker (ARB) therapy on intraoperative hemodynamics and vasopressor use in pediatric patients undergoing cardiac surgery. In a retrospective cohort study of patients younger than 18 years who underwent cardiopulmonary bypass between March 1, 2010, and April 1, 2011, we compared intraoperative hemodynamics and vasopressor use between patients who received preoperative ACE inhibitor/ARB therapy and those who did not. The primary outcome was vasoactive infusion score after cardiopulmonary bypass. The occurrence of hypotension did not differ significantly between the ACE inhibitor/ARB group and the control group during induction of anesthesia or at any time point after cardiopulmonary bypass. At 0, 30, 60, and 90 minutes after cessation of cardiopulmonary bypass, patients on ACE inhibitor/ARB therapy tended to have a higher vasoactive infusion score (7.1, 7.6, 9.4, and 11.3) than patients in the control group (6.3, 6.1, 6.0, and 6.7). Although this difference became more pronounced over time, it did not reach statistical significance. The use of preoperative ACE inhibitors and ARBs in pediatric patients undergoing cardiac surgery did not significantly increase the incidence of hypotension after induction of anesthesia and did not increase significantly the vasoconstrictor requirements upon weaning from cardiopulmonary bypass; however, additional prospective studies are needed.

Platelet Function During Cardiopulmonary Bypass Using Multiple Electrode Aggregometry: Comparison of Centrifugal and Roller Pumps

Blood trauma may be lower with centrifugal pumps (CPs) than with roller pumps (RPs) during cardiopulmonary bypass (CPB), because, unlike RPs, CPs do not compress the tubing, and shear stress is considered lower in CPs than in RPs. However, relative platelet function remains unclear. Using multiple electrode aggregometry (MEA), we compared platelet function with CP and RP. Ten swine underwent CPB for 3 h, with five weaned off using CP and five using RP. Platelet function was measured using MEA, as were hemoglobin concentration and platelet count, before sternotomy, after heparin infusion, 30 min and 3 h after starting CPB, after protamine infusion, and 60 min after stopping CPB. Platelet activation was initiated with adenosine diphosphate (ADP), arachidonic acid (AA), and thrombin receptor-activating protein 6 (TRAP). Fibrinogen, platelet factor 4 (PF4), and β-thromboglobin (β-TG) concentrations were measured before sternotomy and 60 min after stopping CPB. In the CP group and using ADP, aggregation was significantly reduced 30 min (P = 0.019) and 3 h (P = 0.027) after starting CPB, recovering to baseline 60 min after CPB was stopped. In the RP group, aggregation was significantly decreased 30 min (P = 0.007) and 3 h (P = 0.003) after starting CPB and after protamine administration (P = 0.028). With AA, aggregation significantly decreased 30 min after starting CPB in both the CP (P = 0.012) and RP (P = 0.016) groups, slightly increasing 3 h after starting CPB and after protamine infusion, and recovering to baseline 60 min after CPB cessation. With TRAP, aggregation in the CP and RP groups decreased 30 min after starting the pump, although changes were not significant; aggregation gradually recovered after 3 h and returned to baseline 60 min after the pumps were stopped. There were no significant differences at all sampling points of MEA. In both groups, fibrinogen, PF4, and β-TG concentrations were similar 60 min after pump cessation and before sternotomy. Platelet function, evaluated with MEA, was lowest 30 min after CPB was started but did not decrease over time in either group. As assessed by MEA, platelet function using CP and RP did not differ significantly. Platelet dysfunction was caused mainly by initial contact with foreign materials and may not be dependent on type of pump.