Cardiopulmonary Bypass In Adult Patients Research Articles

ATF3: a novel biomarker for the diagnosis of acute kidney injury after cardiac surgery.

BackgroundTo investigate the expression of ATF3 in the blood and urine of adult patients undergoing cardiopulmonary bypass (CPB) surgery and to identify the changes during the perioperative period of CPB, and to determine whether ATF3 can be used as a biological marker for the early diagnosis of acute kidney injury (AKI).MethodsWe prospectively studied 83 patients who underwent elective CPB (ECB). Relevant clinical information was collected. Blood and urine samples were collected preoperatively (T0) and at 2 h (T1), 6 h (T2), 12 h (T3), 24 h (T4), and 48 h (T5) after surgery, and grouped according to the occurrence of AKI. The changes in ATF3 levels were observed, and the accuracy of the diagnosis of AKI was compared through receiver operating characteristic (ROC) curve analysis. Factors influencing the expression of ATF3 at baseline were also analyzed.ResultsA total of 83 adult patients undergoing cardiac surgery with CPB were included, and 42 of them developed AKI. The levels of serum ATF3 (sATF3) in the AKI group were significantly higher than those in the non-AKI group 24 h after surgery, and the difference was statistically significant (662.62±204.72 vs. 586.93±175.87; P=0.0345). Urinary ATF3 (uATF3) increased significantly 6 h after surgery, and the area under the ROC curve (AUC) for diagnosing AKI 12 h after surgery was 0.691 (95% CI: 0.576–0.807). When uATF3 was higher than 1,216 pg/mL, the sensitivity and specificity for the diagnosis of AKI were 0.43 and 0.85, respectively. On the other hand, the preoperative expression of ATF3 was negatively correlated with the preoperative creatinine level, but not affected by the patient’s age, weight, gender, preoperative cardiac function, preoperative blood routine examination and liver function.ConclusionsATF3 can be expressed early in the blood and urine of patients after CPB and can be used as a diagnostic marker for AKI after CPB in adult patients.

Retrospective evaluation of ultrafiltration during cardiac surgery with cardiopulmonary bypass in adult patients with increased neutrophil to lymphocyte ratio

Aim: The aim of this study was to investigate the efficacy of the ultrafiltration (UF) in adult patients undergoing open-heart surgery with cardiopulmonary bypass (CPB) by evaluating the neutrophil to lymphocyte ratio (NLR). Methods: A retrospective case-control study was conducted on 288 adult patients who underwent CPB in a University hospital from January 2016 to December 2018. The study groups were composed of a control group (n=116) of patients who underwent surgery without UF and the study group (n=172) of patients who underwent surgery with UF. All perioperative clinical data, including neutrophil, lymphocyte and platelet count, BUN, creatinine, and C-reactive protein (CRP) values were collected. The efficacy of UF and its association with NLR, neutrophil, lymphocyte and platelet count, postoperative bleeding, extubation time, duration of intensive care unit (ICU) stay and in-hospital stay were analyzed. Results: Neutrophil count, NLR and CRP significantly increased post-operatively compared to pre-operative values (P<0.05). The increased post-operative levels of NLR and decreased platelet counts were significantly associated with UF (P<0.05). Multivariate linear regression analysis revealed that elevated NLR was significantly and independently associated with UF. Conclusion: UF followed by CPB in adult patients undergoing cardiac surgery was associated with increased post-operative NLR and low platelet counts, which nonetheless, were not associated with postoperative complications. UF should be chosen only for selective patients with low hematocrit and should not be chosen to attenuate whole body inflammatory response after CPB in adult cardiac surgery patients.

Population pharmacokinetics of cefazolin before, during and after cardiopulmonary bypass in adult patients undergoing cardiac surgery.

The aims of the present study were to establish a population pharmacokinetic (PPK) model of cefazolin for adult patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) and to assess the probability of target attainment (PTA) for the prophylaxis of surgical site infection (SSI) using cefazolin. Adult patients who underwent cardiac surgery with CPB were enrolled in the prospective study. Blood samples for plasma cefazolin assay were collected, and total and unbound drug concentrations were measured and analysed using the nonlinear mixed-effects modelling (NONMEM) software considering saturable plasma protein binding. Using the PPK model, plasma unbound cefazolin concentration-time courses with current prophylaxis protocols were simulated, and the PTA for common SSI pathogens was estimated. A total of 199 blood samples were obtained from 27 patients. A one-compartment model with first-order elimination plus an on/off CPB compartment best described the data. The population mean for systemic drug clearance (CL) was reduced and that for the volume of distribution (V) was increased during CPB compared with the pre-CPB values. CPB-induced hypoalbuminemia was associated with reduced maximum protein binding (Bmax). The simulation studies suggested that the current dosing protocols are insufficient for attaining PTA > 0.9 throughout surgery against pathogens with minimum inhibitory concentrations (MICs) >8mg/L. A new dosing protocol that achieves a PTA > 0.9 for pathogens with a MIC of 16mg/L was proposed. PPK modelling with simulation may be valuable for devising a cefazolin prophylaxis protocol for patients undergoing cardiac surgery with CPB.

Autologous Priming of Cardiopulmonary Bypass in Adult Patients, Effect on Blood Transfusion, Hemodilution and its Effect on Body Systems

Abstract Background: Development of many techniques conserve blood in cardiac surgery has been established, to avoid the side effects of homologous blood transfusion. One of these techniques is the Retrograde Autologous Priming (RAP); which is a blood conservation technique designed to decrease the severity of hemodilution during cardiopulmonary bypass and thus decreasing perioperative transfusions. Aim of Study: The aim was to examine the safety and efficacy of RAP and its role in decreasing adverse outcomes on body systems after cardiac surgery. Patients and Methods: This work was performed on 60 adult patients indicated for open heart surgery as valvular heart disease or coronary heart disease. 30 patients were operated using RAP technique and 30 patients using ordinary priming method of cardiopulmonary bypass (CPB). Results: The CPB mean time was significantly shorter in the RAP group. The hemoglobin (Hb) level and hematocrit (Hct) concentration in the perioperative and postoperative time as significantly higher in the RAP group also the platelet count was significantly higher in the RAP group (p 0.05) between the two groups. Conclusions: RAP is an efficient and economical method in limiting the amount of priming volume of the CPB system, causing less hemodilution, reducing intra- and postoperative blood transfusion and decreasing adverse effects of hemodi-lution on body systems.

A RANDOMIZED COMPARATIVE STUDY BETWEEN REMOTE ISCHEMIC PRECONDITIONING AND PHARMACOLOGICAL PRECONDITIONING IN MAJOR AORTIC SURGERIES

Background: Cardiopulmonary bypass (CPB) remains an essential element of the surgical correction of most majorcardiovascular lesions. CPB is complicated by multisystem injury, the mechanisms of which include ischemia–reperfusion injury (IRI) and a detrimental systemic inflammatory response. Cardiac, pulmonary and neuronal injury and dysfunction remain important clinical problems after CPB. Aim of the study: The aim of this study was to compare and evaluate the effectiveness of remote ischemic preconditioning and pharmacological preconditioning in reducing cardiac injury inducedby cardiopulmonary bypass in adult patients undergoing major aortic surgeries. Patients and Methods: This study included (42) patients, divided into two groups 21 patients each, Group R: Remote Ischemic Preconditioning (cycles of ischemia and reperfusion of lower limb using blood pressure cuff) and Group P: pharmacological preconditioning (administration of sevoflurane and dexmedetomidine). Results: The current studyshowed postoperative lower elevation in CK total enzyme, CK MB enzyme and troponin I enzyme and decreased inotropic support(adrenaline infusion) requirements post-operatively along with shorter duration of postoperative intubation and postoperative ICU stay in group Pcompared to group R. Conclusion: Pharmacological preconditioning using sevoflurane and dexmedetomidine hasmyocardial protective effect after CPB in adult patients undergoing major aortic surgeries more than remote ischemic preconditioning as reflected by lower elevation in CK total enzyme, CK MB enzyme and troponin I enzyme and decreased inotropic support (adrenaline infusion) requirements postoperatively along with shorter duration of both postoperative intubation and postoperative ICU stay.

Microcirculatory perfusion disturbances following cardiopulmonary bypass: a systematic review

BackgroundMicrocirculatory perfusion disturbances are associated with increased morbidity and mortality in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). Technological advancements made it possible to monitor sublingual microcirculatory perfusion over time. The goal of this review is to provide an overview of the course of alterations in sublingual microcirculatory perfusion following CPB. The secondary goal is to identify which parameter of sublingual microcirculatory perfusion is most profoundly affected by CPB.MethodsPubMed and Embase databases were systematically searched according to PRISMA guidelines and as registered in PROSPERO. Studies that reported sublingual microcirculatory perfusion measurements before and after onset of CPB in adult patients undergoing cardiac surgery were included. The primary outcome was sublingual microcirculatory perfusion, represented by functional capillary density (FCD), perfused vessel density (PVD), total vessel density (TVD), proportion of perfused vessels (PPV), and microvascular flow index (MFI).ResultsThe search identified 277 studies, of which 19 fulfilled all eligibility criteria. Initiation of CPB had a profound effect on FCD, PVD, or PPV. Seventeen studies (89%) reported one or more of these parameters, and in 11 of those studies (65%), there was a significant decrease in these parameters during cardiac surgery; the other 6 studies (35%) reported no effect. In 29% of the studies, FCD, PVD, or PPV normalized by the end of cardiac surgery, and in 24% percent of the studies, this effect lasted at least 24 h. There was no clear effect of CPB on TVD and a mixed effect on MFI.ConclusionCPB during cardiac surgery impaired sublingual microcirculatory perfusion as reflected by reduced FCD, PVD, and PPV. Four studies reported this effect at least 24 h after surgery. Further research is warranted to conclude on the duration of CPB-induced microcirculatory perfusion disturbances and the relationship with clinical outcome.Trial registrationPROSPERO, CRD42019127798

Pulmonary artery perfusion versus no perfusion during cardiopulmonary bypass for open heart surgery in adults.

Available evidence has been inconclusive on whether pulmonary artery perfusion during cardiopulmonary bypass (CPB) is associated with decreased or increased mortality, pulmonary events, and serious adverse events (SAEs) after open heart surgery. To our knowledge, no previous systematic reviews have included meta-analyses of these interventions. To assess the benefits and harms of single-shot or continuous pulmonary artery perfusion with blood (oxygenated or deoxygenated) or a preservation solution compared with no perfusion during cardiopulmonary bypass (CPB) in terms of mortality, pulmonary events, serious adverse events (SAEs), and increased inflammatory markers for adult surgical patients. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, Science Citation Index Expanded, and advanced Google for relevant studies. We handsearched retrieved study reports and scanned citations of included studies and relevant reviews to ensure that no relevant trials were missed. We searched for ongoing trials and unpublished trials in the World Health Organization International Clinical Trials Registry Platform (ICTRP) and at clinicaltrials.gov (4 July 2017). We contacted medicinal firms producing preservation solutions to retrieve additional studies conducted to examine relevant interventions. We included randomized controlled trials (RCTs) that compared pulmonary artery perfusion versus no perfusion during CPB in adult patients (≧ 18 years). Two independent review authors extracted data, conducted fixed-effect and random-effects meta-analyses, and calculated risk ratios (RRs) or odds ratios (ORs) for dichotomous outcomes. For continuous data, we have presented mean differences (MDs) and 95% confidence intervals (CIs) as estimates of the intervention effect. To minimize the risk of systematic error, we assessed risk of bias of included trials. To reduce the risk of random errors caused by sparse data and repetitive updating of cumulative meta-analyses, we applied Trial Sequential Analyses (TSAs). We used GRADE principles to assess the quality of evidence. We included in this review four RCTs (210 participants) reporting relevant outcomes. Investigators randomly assigned participants to pulmonary artery perfusion with blood versus no perfusion during CPB. Only one trial included the pulmonary artery perfusion intervention with a preservation solution; therefore we did not perform meta-analysis. Likewise, only one trial reported patient-specific data for the outcome "pulmonary events"; therefore we have provided no results from meta-analysis. Instead, review authors added two explorative secondary outcomes for this version of the review: the ratio of partial pressure of oxygen in arterial blood (PaO2) to fraction of inspired oxygen (FiO2); and intubation time. Last, review authors found no comparable data for the secondary outcome inflammatory markers.The effect of pulmonary artery perfusion on all-cause mortality was uncertain (Peto OR 1.78, 95% CI 0.43 to 7.40; TSA adjusted CI 0.01 to 493; 4 studies, 210 participants; GRADE: very low quality). Sensitivity analysis of one trial with overall low risk of bias (except for blinding of personnel during the surgical procedure) yielded no evidence of a difference for mortality (Peto OR 1.65, 95% CI 0.27 to 10.15; 1 study, 60 participants). The TSA calculated required information size was not reached and the futility boundaries did not cross; thus this analysis cannot refute a 100% increase in mortality.The effect of pulmonary artery perfusion with blood on SAEs was likewise uncertain (RR 1.12, 95% CI 0.66 to 1.89; 3 studies, 180 participants; GRADE: very low quality). Data show an association between pulmonary artery perfusion with blood during CPB and a higher postoperative PaO2/FiO2 ratio (MD 27.80, 95% CI 5.67 to 49.93; 3 studies, 119 participants; TSA adjusted CI 5.67 to 49.93; GRADE: very low quality), although TSA could not confirm or refute a 10% increase in the PaO2/FiO2 ratio, as the required information size was not reached. The effects of pulmonary artery perfusion with blood during cardiopulmonary bypass (CPB) are uncertain owing to the small numbers of participants included in meta-analyses. Risks of death and serious adverse events may be higher with pulmonary artery perfusion with blood during CPB, and robust evidence for any beneficial effects is lacking. Future randomized controlled trials (RCTs) should provide long-term follow-up and patient stratification by preoperative lung function and other documented risk factors for mortality. One study that is awaiting classification (epub abstract with preliminary results) may change the results of this review when full study details have been published.

Whole Blood

To the Editor: Dr. Weiskopf's editorial, “Reconstructing Deconstructed Blood for Trauma,”1should prompt serious examination of conventional blood banking practices, not just as they pertain to trauma, but also to other areas of patient care that involve significant blood component transfusion. He mentions two small trials in adult cardiac surgery that have had less-than-convincing results,2,3but he omitted one landmark study in pediatric cardiac surgery. Manno et al. at the Children's Hospital of Philadelphia, Pennsylvania, compared use of whole blood and “reconstituted” blood (packed erythrocytes, fresh frozen plasma, and platelets) in children undergoing cardiac surgery with cardiopulmonary bypass.4This study showed that in the highest risk group, children less than 2 yr of age having high complexity surgery, postoperative blood loss in the group receiving reconstituted blood was around twice that of the whole blood group. Very fresh whole blood did not have a significant advantage over whole blood stored for 24–48 h. In addition, they showed that the platelets in reconstituted blood had significantly more abnormal aggregation in response to adenosine diphosphate, epinephrine, and collagen, suggesting that preservation of platelet function may be one reason for the superiority of whole blood in treating the postcardiopulmonary bypass coagulopathy. Lavee et al. showed a similar effect of whole blood on preservation of platelet function by showing that platelet aggregation as assessed by electron microscopy after cardiopulmonary bypass in adult patients was restored by 1 unit of whole blood to a level equivalent to 8–10 platelet units.5It is not only patients (of trauma and otherwise) who would benefit from more widespread use of whole blood in terms of clinical outcome and limitation of their exposure to donors. Somewhat counterintuitively, use of whole blood may also help eke out a dwindling blood supply by being substantially more efficient than components, particularly platelets, which may have lost much of their efficacy in the process of being separated and stored apart. It will require effort by clinicians to convince the blood bank community that the whole is more than the sum of the parts.

Effect of Subzero-Balanced Ultrafiltration on Lung Gas Exchange Capacity after Cardiopulmonary Bypass in Adult Patients with Heart Valve Disease

This study was conducted to evaluate the effect of a new ultrafiltration technique--the subzero-balanced ultrafiltration (SBUF)--on lung gas exchange capacity after cardiopulmonary bypass (CPB) in adult patients with heart valve disease. Attenuation of lung gas exchange capacity is one of the most common manifestations of an inflammatory response after CPB. Ninety-four patients who required CPB for cardiac surgery were randomized into 2 groups according to whether they received SBUF. Gas exchange capacity expressed as the oxygen index (OI), the respiratory index (RI), and the alveolar-arterial oxygen pressure difference (P(A-a)O2) were measured after intubation (T1), at the termination of CPB (T2), on admission to the intensive care unit (ICU) (T3), at postoperative hour 6 (T4), and at postoperative hour 12 (T5). There were no significant differences in gas exchange capacity between the 2 groups at T1, T4, and T5. CPB produced significant changes in OI, RI, and P(A-a)O2 in the control group, whereas these changes were not significantly different in the study group. The OI in the study group was significantly higher at T2, and RI and P(A-a)O2 were significantly lower at T2 and T3. In the study group, the intubation time was shorter, and the transfusion volume within 24 hours postoperatively was less. The 2 groups were comparable with respect to the incidence of respiratory complications, length of stay in the ICU, duration of hospital stay, need for infusions of inotropic agents, and drainage volumes within 24 hours postoperatively. SBUF during CPB can produce an immediate improvement in lung gas exchange capacity, which may effectively minimize pulmonary dysfunction in adult patients undergoing cardiac surgery.

Impaired Autoregulation of Cerebral Blood Flow During Rewarming from Hypothermic Cardiopulmonary Bypass and Its Potential Association with Stroke

Patient rewarming after hypothermic cardiopulmonary bypass (CPB) has been linked to brain injury after cardiac surgery. In this study, we evaluated whether cooling and then rewarming of body temperature during CPB in adult patients is associated with alterations in cerebral blood flow (CBF)-blood pressure autoregulation. One hundred twenty-seven adult patients undergoing CPB during cardiac surgery had transcranial Doppler monitoring of the right and left middle cerebral artery blood flow velocity. Eleven patients undergoing CPB who had arterial inflow maintained at >35 degrees C served as controls. The mean velocity index (Mx) was calculated as a moving, linear correlation coefficient between slow waves of middle cerebral artery blood flow velocity and mean arterial blood pressure. Intact CBF-blood pressure autoregulation is associated with an Mx that approaches 0. Impaired autoregulation results in an increasing Mx approaching 1.0. Comparisons of time-averaged Mx values were made between the following periods: before CPB (baseline), during the cooling and rewarming phases of CPB, and after CPB. The number of patients in each phase of CPB with an Mx >4.0, indicative of impaired CBF autoregulation, was determined. During cooling, Mx (left, 0.29 +/- 0.18; right, 0.28 +/- 0.18 [mean +/- SD]) was greater than that at baseline (left, 0.17 +/- 0.21; right, 0.17 +/- 0.20; P <or= 0.0001). Mx increased during the rewarming phase of CPB (left, 0.40 +/- 0.19; right, 0.39 +/- 0.19) compared with baseline (P <or= 0.001) and the cooling phase (P <or= 0.0001), indicating impaired CBF autoregulation. After CPB, Mx (left, 0.27 +/- 0.20; right, 0.28 +/- 0.21) was higher than at baseline (left, P = 0.0004; right, P = 0.0003), no different than during the cooling phase, but lower than during rewarming (left, P <or= 0.0001; right, P <or= 0.0005). Forty-three patients (34%) had an Mx >or=0.4 during the cooling phase of CPB and 68 (53%) had an average Mx >or=0.4 during rewarming. Nine of the 11 warm controls had an average Mx >or=0.4 during the entire CPB period. There were 7 strokes and 1 TIA after surgery. All strokes were in patients with Mx >or= 0.4 during rewarming (P = 0.015). The unadjusted odds ratio for any neurologic event (stroke or transient ischemic attack) for patients with Mx >or= 0.4 during rewarming was 6.57 (95% confidence interval, 0.79 to 55.0, P < 0.08). Hypothermic CPB is associated with abnormal CBF-blood pressure autoregulation that is worsened with rewarming. We found a high rate of strokes in patients with evidence of impaired CBF autoregulation. Whether a pressure-passive CBF state during rewarming is associated with risk for ischemic brain injury requires further investigation.

Axillary and tympanic membrane temperature measurements are unreliable early after cardiopulmonary bypass

Inaccurate measurements of body temperature following cardiopulmonary bypass may be associated with serious complications. The purpose of this study was to determine whether axillary and tympanic temperature measurements correlate with the urinary bladder temperature in the early postcardiac surgery period. Forty-nine adult patients who underwent cardiac surgery under cardiopulmonary bypass at our institution were prospectively studied. Urinary bladder, right axillary, right tympanic and left tympanic temperature measurements were simultaneously recorded at 0, 6, 12 and 18 h following cardiopulmonary bypass. Patients had one to four sets of recordings and a total of 629 temperature measurements were recorded. The mean difference (bias) between the bladder and each of the other methods and limits of agreement were calculated using Bland and Altman method. The mean core body temperature recorded from the bladder on admission to the intensive care unit was 36.4 degrees C. After 6, 12 and 18 h the mean core body temperature was 37.4 degrees C (range: 35.2-39.0), 37.5 degrees C and 37.45 degrees C, respectively. The mean differences (bias) between the bladder temperature and the other three methods were: left tympanic, 0.65 degrees C (95% CI: -0.24 to 1.58); right tympanic, 0.57 degrees C (95% CI: -0.48 to 1.63) and right axillary, 0.55 degrees C (95% CI: -0.27 to 1.36). The axilla and tympanic membrane are unreliable sites for core body temperature measurement early after cardiopulmonary bypass in adult patients and clinical decisions should be based on more reliable methods.

Isoflurane may not influence postoperative cardiac troponin I release and clinical outcome in adult cardiac surgery

Isoflurane has been shown experimentally to protect the myocardium against infarction but the clinical relevance of these findings is not yet well established. We therefore evaluated the effects of isoflurane administration before cardiopulmonary bypass (CPB) on postoperative cardiac troponin I (cTnI) release and clinical outcome in a large group of adult patients scheduled for cardiac surgery. Three hundred and fifty-nine consecutive patients were included prospectively in an open observational study and divided into two groups according to whether or not isoflurane was administered before CPB. Postoperative cTnI release, in-hospital mortality, time to discharge from hospital, time to extubation and non-fatal postoperative cardiac events (number of internal cardioversions, need for inotropic support, ischaemic events, dysrhythmias and/or conduction abnormalities) were recorded. Two hundred and twenty-one (62%) patients did not receive isoflurane and 138 (38%) received isoflurane (1.3% [1.0-1.8%] minimum alveolar concentration over 22 [15-331 min). Postoperative cTnI release was not significantly different between the control and isoflurane groups (5.9 [1.0-336.8] vs. 6.0 [1.5-392.0] ng mL(-1), P = 0.88). No significant differences were found in non-fatal cardiac events (63% vs. 57%, P = 0.22) and in-hospital mortality (1.8% vs. 1.4%, P = 0.79) between the control and isoflurane groups. No significant effect was observed on postoperative cTnI release and in-hospital outcome when isoflurane was added to standardized intravenous anaesthesia before CPB in adult patients undergoing cardiac surgery.

Changes in body temperature during profound hypothermic cardiopulmonary bypass in adult patients undergoing aortic arch reconstruction.

Our aim was to characterize changes in body temperatures during profound hypothermic cardiopulmonary bypass (CPB) conducted with the sternum opened. In ten adult patients who underwent profound hypothermic (< 20 degrees C) CPB for aortic arch reconstruction, pulmonary arterial temperature (PAT), nasopharyngeal temperature (NPT), forehead deep-tissue temperature (FHT), and urinary bladder temperature (UBT) were recorded every 1 min throughout the surgery. In addition, the CPB venous line temperature (CPBT), a reasonable indicator of mixed venous blood temperature during CPB and believed to best reflect core temperature during stabilized hypothermia on CPB, was recorded during the period of total CPB. PAT began to change immediately after the start of cooling or rewarming, closely matching the CPBT ( r = 0.98). During either situation, the other four temperatures lagged behind PAT ( P < 0.05); however, NPT followed PAT more closely than the other three temperatures ( P < 0.05). During stabilized hypothermia, PAT, NPT, and FHT, but not UBT, closely matched the CPBT, with gradients of less than 0.5 degrees C. During induction of profound hypothermia and its reversal on total CPB with the heart in situ, a PA catheter thermistor, presumably because of its placement immediately behind the superior vena cava, would provide a reliable measure of the mixed venous blood temperature. During stabilized profound hypothermia, PAT, NPT, and FHT, but not UBT, serve as a reliable index of core temperature.

Exhaled nitric oxide level decreases after cardiopulmonary bypass in adult patients.

To measure exhaled nitric oxide (NO) and compare it with lung function after cardiopulmonary bypass (CPB) in adult patients. Pulmonary dysfunction is sometimes observed after CPB. Impaired production of NO may account for this dysfunction. Prospective, single-center, observational study. University hospital operating room, intensive care unit. Sixteen adult patients undergoing cardiac surgery with CPB. None except cardiac surgery with CPB. Exhaled NO was measured continuously by the chemiluminescence method and was expressed as the peak and mean NO concentrations, and the NO output (VNO). These parameters were calculated by averaging four sequential tidal NO values. The data were obtained serially from before CPB to 16 hrs after CPB. Lung function was evaluated by monitoring lung compliance, pulmonary artery pressure, and alveolar-arterial oxygen difference (P(A-a)O2). The cardiac index did not change except for a significant increase at 16 hrs compared with 6 hrs after CPB. Peak NO, mean NO, and VNO decreased from 15.4 +/- 2.0 ppb (before CPB) to 8.2 +/- 0.8 ppb (6 hrs after CPB), from 5.7 +/- 0.7 ppb to 2.8 +/- 0.6 ppb, and from 29.2 +/- 3.1 nL/min to 15.7 +/- 2.2 nL/min, respectively. These changes were associated with the increases in pulmonary artery pressure and alveolar-arterial oxygen difference, and the decrease in lung compliance. VNO recovered to the level measured before CPB 16 hrs after CPB, which was consistent with the physiologic recovery in pulmonary hypertension, lung compliance, and gas exchange. Measurement of exhaled NO as VNO, which was associated with lung dysfunction, may be an indicator of lung injury in adult patients after cardiopulmonary bypass.

Pharmacokinetic model-driven infusion of sufentanil and midazolam during cardiac surgery: Assessment of the prospective predictive accuracy and the quality of anesthesia

Objective: To evaluate the prospective predictive accuracy and the quality of anesthesia of pharmacokinetic model-driven infusion of sufentanil and midazolam designed to establish and maintain a plasma level of drug during cardiac surgery. Design: Prospective analysis. Setting: Operating room at a university hospital. Participants: Twenty adult patients younger than 75 years old scheduled for valvular or coronary artery bypass graft surgery. Interventions: Patients were anesthetized using a variable predicted concentration of sufentanil (1 to 10 ng/mL) combined with a stable predicted concentration of midazolam (100 ng/mL). Measurements and Main Results: For each patient, arterial samples were taken before (6 samples), during (2 samples), and after (2 samples) cardiopulmonary bypass (CPB). Plasma sufentanil and midazolam concentrations were measured by specific radioimmunoassay and high-performance liquid chromatography techniques. Predicted sufentanil and midazolam concentrations were derived using the data sets of Gepts et al and Maitre et al. The predictive performance, the percentage prediction error (PE), and the absolute percentage error were calculated for each sample. The bias, inaccuracy, and dispersion were assessed by determining the median of the individual medians of the prediction errors (MDPE), the median of the individual median of the absolute prediction errors (MDAPE), and the 10th and 90th percentiles of PE. For midazolam, the inaccuracy was low (MDAPE < 21%), but CPB was associated with a dilution of the measured concentration associated with a negative bias. For sufentanil, the inaccuracy was also low before CPB (MDAPE = 18%) but increased during and after CPB (MDAPE > 40%). During the whole procedure, the hemodynamic control necessitated only a few interventions. Conclusions: Pharmacokinetic model–driven infusion of sufentanil and midazolam using the pharmacokinetic sets of Gepts et al and Maitre et al is a safe and accurate anesthetic technique before CPB in adult patients undergoing cardiac surgery when high sufentanil (1 to 10 ng/mL) and low midazolam (100 ng/mL) predicted plasma concentrations are targeted. Copyright © 2000 by W.B. Saunders Company

Impact of heparin bonding on pediatric cardiopulmonary bypass: a prospective randomized study

Background. Heparin-coated circuits reduce the inflammatory response to cardiopulmonary bypass in adult patients; however, little is known about its effects in the pediatric population. Two studies were performed to assess this technology’s impact on inflammation and clinical outcomes. Methods. In a pilot study, complement and interleukins were measured in 19 patients who had either uncoated cardiopulmonary bypass circuits or heparin-bonded circuits. Subsequently, 23 additional patients were studied in a randomized fashion. Respiratory function and blood product utilization were recorded. Results. In the pilot study, heparin-bonded circuit patients had less complement 3a ( p < 0.001) and interleukin-8 ( p < 0.05) compared with uncoated cardiopulmonary bypass circuit patients. The randomized study revealed that the heparin-bonded circuit was associated with reduced complement 3a ( p = 0.02). Multiple variable analysis revealed that the following postoperative variables were increased with bypass time ( p = 0.01) and diminished with heparin-bonded circuits: interleukins ( p = 0.01), peak airway pressures ( p = 0.05), and prothrombin time ( p = 0.03). Conclusions. Heparin-bonded circuits significantly reduce cytokines and complement during cardiopulmonary bypass and lower interleukin levels postbypass; they were also associated with improved pulmonary and coagulation function. Heparin-bonded circuits ameliorate the systemic inflammatory response in pediatric patients from cardiopulmonary bypass.

Hemodynamic performance and histamine levels after desmopressin acetate administration following cardiopulmonary bypass in adult patients

Sixteen patients undergoing cardiac surgical procedures were prospectively randomized into two groups to study the hemodynamic and histamine-releasing effects of desmopressin acetate (DDAVP) administration after cardiopulmonary bypass. Ten minutes after administration of protamine for reversal of heparin, DDAVP, 0.3 μg/kg, was infused intravenously over 5 seconds in group 1, and the same dose of DDAVP was administered over 5 minutes as an infusion in group 2. There were no statistical differences between baseline values in groups 1 and 2. DDAVP decreased mean arterial pressure by 30% and 25% in groups 1 and 2 (69 ± 5 mm Hg to 52 ± 8 mm Hg, P < 0.005, and 79 ± 20 mm Hg to 55 ± 8 mm Hg, P < 0.005), respectively. The hypotension in both groups was related to decreases in systemic vascular resistance (1,616 ± 262 dyne · s · cm −5 to 1,073 ± 199 dyne · s · cm −6, P < 0.005, and 1,850 ± 541 dyne · s · cm −5 to 1,144 ± 214 dyne · s · cm −5, P < 0.005). Phenylephrine infusion successfully treated the DDAVP-induced hypotension in all patients. Arterial histamine levels at 3 and 5 minutes after infusion of DDAVP did not differ significantly from baseline values. It is concluded that DDAVP at 0.3 μg/kg is a potent vasodilator when administered intravenously and that histamine is not involved in producing its hypotensive effects.

Initial clinical experience with a low pressire drop membrane oxygenator for cardiopulmonary bypass in adult patients

The new Travenol oxygenator is composed of 80 parallel blood pathways. Microporous membrane separates the blood and gas compartments. The membrane surface area is 3 m 2, with a pore size of 0.01 microns. Venous blood drains directly from the patient through the oxygenator, then through an integral heat exchanger and into a reservoir, from which a single arterial pump returns the blood to the patient. The advantage of this configuration of membrane oxygenator is simplicity of setup and operation. A disadvantage that we have observed is an apparent variation in resistance to blood flow through the oxygenator during clinical perfusion. Construction changes in a later version of the oxygenator have reduced the resistance to flow through the blood pathway. This device has been used for 20 perfusions at moderate hypothermia (mean 31.8 °C) in patients up to 2.1 m 2 body surface area for up to 313 minutes. Blood flow was 2.1 to 5.6 liters/min, partial arterial oxygen pressure 100 to 394 torr, partial arterial carbon dioxide pressure 19 to 57 torr (mean 37 torr) and, arterial pH 7.29 to 7.56 (mean 7.41). Oxygen transfer was as high as 230 ml/min. This integral oxygenator-heat exchanger-reservoir is operated like a bubble oxygenator, with direct venous drainage through the device and a single pump, but it uses a membrane oxygenator for gas exchange to eliminate the detrimental effects of bubbles.