Perfusion recent issues

Character and Thinking

Punjabi, P. P — Tue, 17 Nov 2009 04:06:17 PST

Clinical evaluation of minimized extracorporeal circulation in high-risk coronary revascularization: impact on air handling, inflammation, hemodilution and myocardial function

Gunaydin, S., Sari, T., McCusker, K., Schonrock, U., Zorlutuna, Y. — Tue, 17 Nov 2009 04:06:17 PST

Objective: We examined intraoperative microembolic signals (GME), inflammatory response, hemolysis, perioperative regional cerebral oxygen saturation (rSO₂), myocardial protection and desorbed protein amount on oxygenator fibers in high-risk patients undergoing coronary revascularization (CABG) with minimized and conventional cardiopulmonary bypass (CPB). Methods: Over a ten-month period, 40 Euroscore 6+ patients undergoing CABG were prospectively randomized to one of the two perfusion protocols (N=20): Group 1: minimized extracorporeal circuits (Mini-CPB) (ROCsafe MPC, Terumo, Ann Arbor, MI, USA) and Group 2: conventional extracorporeal circuits (CECC) (Capiox SX18, Terumo, USA). Serum creatinine kinase-MB (CKMB), free hemoglobin, interleukin-6 (IL-6) and C3a levels were measured. Blood samples were collected at T1: following induction of anesthesia; T2: thromboelastography control; T3:15 min after commencement of CPB; T4: before cessation of CPB; T5: 15 min after protamine reversal and T6: ICU. Results: Serum IL-6 levels were significantly lower in the Mini-CPB group at T4 and T5 and C3a levels were significantly less in the Mini-CPB group at T3, T4 and T5 vs. CECC (p<0.01). CKMB levels in coronary sinus blood demonstrated well preserved myocardium in the Mini-CPB group. Percentage expression of neutrophil CD11b/CD18 levels were significantly lower in the Mini-CPB group at T4 and T5 (p<0.05). There were no significant differences in air handling characteristics or free plasma hemoglobin levels in either circuit. rSO₂ measurements were significantly better at T3 and T4 in the Mini-CPB vs. CECC (p<0.05) and always higher in the Mini-CPB during follow-up. Blood protein adsorption analysis of oxygenator membranes demonstrated a significantly increased amount of microalbumin on CECC fibers (p<0.05). Conclusion: Mini-CPB provided a comfort and safety level similar to conventional control via satisfactory air handling, attenuated inflammatory response and hemodilution, with a better clinical outcome in patients undergoing high-risk CABG.

The use of a mini bypass circuit for minimally invasive mitral valve surgery

Fernandes, P., MacDonald, J., Cleland, A., Mayer, R., Fox, S., Kiaii, B. — Tue, 17 Nov 2009 04:06:18 PST

Introduction: The purpose of the study is to clinically evaluate minimally invasive mitral valve surgeries (MIMVS) using a mini bypass circuit. The challenge to perfusion is to keep pace with MIMVS, with demonstrated improvements in perfusion-related technologies.

Methods: From October 28, 2005 to September 10, 2008, we retrospectively evaluated thirty-four elective cases which used the mini-circuit (Medtronic Resting Heart System®), with respect to safety, efficacy, cannulation technique, blood usage, resultant hemoglobin, length of ICU and hospital stay, and complications.

Conclusion: The Medtronic Resting Heart System® alleviates many factors, such as high shear stress, turbulence, air to blood interface and decreased oncotic pressure caused by hemodilution, providing more efficient perfusion to our MIMVS patients. We demonstrate, with minor circuit modifications and attention to venous air issues, that this mini-circuit can be used safely and effectively, while being associated with improvements in patient outcomes.

Treatment of massive pulmonary embolism utilizing a multidisciplinary approach: a case study

Griffith, K. E., Jenkins, E., Haft, J. — Tue, 17 Nov 2009 04:06:18 PST

Massive pulmonary embolism (PE) is associated, historically, with a high mortality rate.Treatment options include systemic anticoagulation, catheter-directed thrombolytic therapy, surgical embolectomy, fragmentation techniques, and catheter embolectomy. Extracorporeal membrane oxygenation (ECMO) repeatedly has demonstrated effectiveness in providing cardiopulmonary support for the patient with a massive PE too unstable to undergo thrombolysis or embolectomy. The present case study describes a morbidly obese patient, status post gastric bypass surgery, who presented with PE, and acute respiratory and cardiac failure. A description of the patient’s management plan, which includes a simple, rapidly deployed ECMO system (Levitronix^® CentriMag^® and Jostra Quadrox D), systemic- and catheter-directed thrombolytic therapy and rheolytic thrombectomy (AngioJet^® Series 3000, Possis Medical, Minneapolis, MN).

Case control study of gastrointestinal complications after cardiopulmonary bypass heart surgery

Zhang, G., Wu, N., Liu, H., Lv, H., Yao, Z., Li, J. — Tue, 17 Nov 2009 04:06:18 PST

Background: Gastrointestinal complications (GIC) after cardiopulmonary bypass (CPB) surgery are rare, but, nevertheless, extremely dangerous.The identification of risks for GIC may be helpful in planning appropriate perioperative management strategies. The aim of the present study was to analyze perioperative factors of GIC in patients undergoing CPB surgery. Methods: We retrospectively analysed 206 patients who underwent GIC after cardiopulmonary bypass surgery from 2000 to 2007 and compared them with 206 matched control patients (matched for surgery, temperature, hemodilution and date). Univariate analysis and multiple logistic regression analysis were performed on 12 risk factors. Result: Sex and types of cardioplegia perfusate did not significantly influence the GIC after CPB surgery. Multiple logistic regression revealed that CPB time, preoperative serum creatinine (PSC) ≥ 179 mg/dL, emergency surgery, perfusion pressure ≤40mmHg, low cardiac output syndrome (LCOS), age ≥ 61, mechanical ventilation ≥96 h, New York Heart Association (NYHA) class III and IV were predictors of the occurrence of GIC after CPB surgery. Perfusion pressure and aprotinin administration were protective factors. Conclusion: Gastrointestinal complications after CPB surgery could be predictive in the presence of the above risk factors. This study suggests that GIC can be reduced by maintenance of higher perfusion pressure and shortening the time on CPB and ventilation.

Increase in plasma free haemoglobin during cardiopulmonary bypass in heart valve surgery: assessment of renal dysfunction by RIFLE classification

Vanek, T., Snircova, J., Spegar, J., Straka, Z., Horak, J., Maly, M. — Tue, 17 Nov 2009 04:06:18 PST

Heart valve surgery carries a high risk of renal insufficiency as an independent risk factor due to prolonged cardiopulmonary bypass. Multiple causes of cardiopulmonary bypass-associated renal damage have been described, and haemoglobin-induced renal injury is presently being investigated. Forty-three patients scheduled for heart valve surgery (mostly combined) were enrolled in the prospective study. Plasma free haemoglobin (PFH) levels were evaluated by photocolorimetric measurement at the start of procedures (t₀) and before the end of extracorporeal circulation (t₁). A statistically significant increase in PFH levels during cardiopulmonary bypass was detected [median values (interquartile range) - t₀: 62.0 (53.4) mg/L, t₁: 320.4 (352.2) mg/L], P < 0.001. A significant regression relationship between the duration of cardiopulmonary bypass and the increased PFH was found (Spearman’s correlation coefficient 0.628, P < 0.001). In some elderly patients, the tendency towards a high release of PFH during cardiopulmonary bypass was more pronounced, but the overall association between age and PFH levels was of borderline significance (P = 0.077). The correlation between PFH and post-operative serum creatinine was low and non-significant, but the latter correlated highly with the pre-operative serum creatinine values (Spearman’s correlation coefficient reached values of 0.6-0.7, P < 0.001). Patients were classified according to the Risk of renal failure, Injury to the kidney, Failure of kidney function, Loss of kidney function and End-stage renal failure (RIFLE) classification for acute renal dysfunction during post-operative days 1 — 4; the influence of PFH levels at t₁ on the consequent RIFLE classification was not proven (P=0.648), but 4 patients in the Injury category had shown a higher median value of PFH (433.6 mg/L) in comparison with the others (29 patients with no acute renal dysfunction - 313.7 mg/L, 10 patients at Risk - 330.1 mg/L).

Regional cerebral perfusion for surgical correction of neonatal aortic arch obstruction

Zhang, H., Cheng, P., Hou, J., Li, L., Liu, H., Liu, R., Ji, B., Luo, Y. — Tue, 17 Nov 2009 04:06:18 PST

One-stage repair of aortic arch obstruction and associated cardiac anomalies is a surgical challenge in infants.The purpose of the present study is to review the current outcome using regional cerebral perfusion (RCP) during a procedure correcting interrupted aortic arch (IAA) and also isolated aortic coarctation (CoA) and CoA combined with hypoplastic aortic arch (CoA-HyAA) in our center. Between January 2007 and July 2008, 24 infant patients with interrupted aortic arch (IAA) (n=3), isolated aortic coarctation (iCoA) (n=9) and aortic coarctation with hypoplastic aortic arch (CoA-HyAA) (n=12) underwent one-stage surgical correction in our hospital. End-to-end anastomosis was employed in 12 infants (IAA n=3 and iCoA n=9); for the other 12 patients with CoA-HyAA, an end-to-end extended anastomosis was used in 8 cases, end-to-side anastomosis in 2 cases, and composite heterologous pericardial patch in 2 cases. RCP with 40 mL/kg/min through the innominate artery during aortic arch reconstruction was employed for all pediatric patients. One single-dose histidine-ketoglutarate-tryptophan (HTK) solution was used for myocardial protection during CPB. Cardiopulmonary bypass time and aortic cross-clamp time were 165.6±32.4min and 81.7±30.0min, respectively. The mean regional cerebral perfusion time was 31.0±10.6min; lowest nasopharyngeal temperature was 19.1±1.1°C. Operative mortality rate in both groups was 8.3%. Mean follow-up was 10.5±4.8 months. There was no late mortality or postoperative neurologic, renal or hepatic complications. All patients are asymptomatic and are developing normally. One-stage total arch repair using the RCP technique is an excellent method that may minimize neurologic and renal complications. Our surgical strategy for arch anomaly has a low rate of residual and recurrent coarctation when performed in these infants.

Risk factors for bleeding in pediatric post-cardiotomy patients requiring ECLS

Tue, 17 Nov 2009 04:06:18 PST

Background/Objective: There is limited literature documenting bleeding patterns in pediatric post-cardiotomy patients on extracorporeal life support (ECLS). This retrospective review details bleeding complications and identifies risk factors for bleeding in these patients.

Methods: Records from 145 patients were reviewed. Patients were divided into excessive (E) and non-excessive (NE) bleeding groups based on blood loss.

Results: Excessive bleeding occurred predominantly from 0-6h. Longer CPB duration (NE=174±8min; E=212±16; p=0.02) and lower platelet counts (NE=104.8±50K; E=84.3±41K; p=0.01) were associated with excessive bleeding during the first 6h (p=0.005). Use of intraoperative protamine with normal platelets was associated with decreased bleeding from 7-12h post-ECLS (p=0.002). Most mediastinal exploration occurred >49h post-ECLS, with decreased bleeding post-exploration in E patients.

Conclusions: The majority of pediatric post-cardiotomy ECLS bleeding occurs early after support initiation. Longer CPB time and thrombocytopenia increased bleeding 0-6h post-ECLS. Since early bleeding may be coagulopathic in origin, an approach to minimize bleeding includes protamine administration and aggressive blood product replacement with target platelet counts of 100-120K. Surgical exploration should follow if additional hemostasis is necessary.

Analysis of the risk factors of postoperative respiratory dysfunction of type A aortic dissection and lung protection

Luo, H.-y., Hu, K.-j., Zhou, J.-y., Wang, C.-s. — Tue, 17 Nov 2009 04:06:18 PST

Aim: Retrospectively to analyze the risk factors of postoperative respiratory dysfunction (RD) in 196 patients with type A dissection operated on with cerebral perfusion and a lower body hypothermia circulatory arrest (HCA) and to investigate the method of the lung protection.

Methods: From January 2005 to April 2008, 196 patients with type A dissection underwent surgical repair with cerebral perfusion and HCA. There were 142 male patients and 54 female patients, with ages from 17 to 78 years. Antegrade selective cerebral perfusion (SCP) through the axillary artery was performed for 168 patients and retrograde cerebral perfusion (RCP) from the superior vena cava for 28 patients. All the factors underwent univariate and multivariate analysis.

Results: Mean cardiopulmonary bypass (CPB) duration was (186±56) minutes and mean cerebral perfusion time was (35±15) minutes; mean HCA time was (39±14) minutes. Postoperative RD was detected in 26 patients (13.3%). Multivariate analysis showed that the longer duration of circulatory arrest (CA), P=0.008, OR=1.048, and the higher temperature in the bladder during CA, P=0.002, OR=1.614, were independent risk factors of postoperative RD. There was a higher mortality (23.1%, P=0.025) in patients with postoperative RD when compared with the other patients.

Conclusion: The longer duration of CA and the higher temperature in the bladder during CA were found to be the independent risk factors of postoperative RD after type A aortic dissection surgery. Attention should be paid to lung protection for these patients and the adjunct of continuing descending aortic perfusion and cerebral perfusion should be a safe and feasible procedure and it would be valuable to perform a prospective trial.

Bloodless aortic valve and ascending aorta replacement surgery requiring circulatory arrest: two case studies

Schill, D. M. — Tue, 17 Nov 2009 04:06:18 PST

Blood and/or blood product transfusions are common during and after complicated cardiac procedures. Replacement of the aortic valve, ascending aorta, and coronary implantation requiring circulatory arrest are high-risk procedures. Blood product transfusions only add to the morbidity and mortality rates associated with these types of procedures. Perfusion strategies must be incorporated to decrease the effects of hemodiluton due to cardiopulmonary bypass (CPB), and preserve platelets and clotting factors needed for hemostasis, post-operatively. We are reporting two consecutive cases where the patients presented with aortic valve stenosis accompanying an ascending aortic aneurysm requiring surgical correction using circulatory arrest. Neither patient required any blood or blood product donation throughout their hospital stay. Our strategies included minimizing our bypass circuit, utilization vacuum-assisted venous drainage, plasma sequestration, total circuit retrograde autologous priming (RAP), and cell salvage.

Does remote ischemic preconditioning prevent delayed hippocampal neuronal death following transient global cerebral ischemia in rats?

Tue, 17 Nov 2009 04:06:18 PST

Objective: To determine if remote ischemic preconditioning (RIPC) induced by transient limb ischemia is protective against delayed hippocampal neuronal death in rats undergoing transient global cerebral ischemia (GCI).

Method: Animals were randomized into 3 groups: Group I (Control, n = 5) underwent sham procedure, namely, general anesthesia x 2, without cerebral ischemia; Group II (RIPC + GCI, n = 5) was subjected to RIPC, induced by transient left hind limb ischemia under general anesthesia prior to GCI; Group III (GCI only, n = 5) underwent sham procedure under general anesthesia prior to GCI. Twenty-four hours after the RIPC or sham procedure, a transient GCI was induced for 8 minutes in Groups II and III by means of bilateral common carotid artery occlusion and hypotension. Hippocampal CA1 neurons were histologically examined at 7 days after ischemia.

Results: There was no significant difference between the RIPC group and the ischemia only group. The number of neurons in the RIPC group were 0.90 (95% CI 0.20, 4.08) times the number in the ischemia group (p=0.89). The number of neurons in the RIPC group were 0.03 (95% CI 0.01, 0.10) times the number in the Control group (p=0.0001). Conclusion: Second window of the RIPC does not prevent hippocampal CA1 neuronal death at 7 days after transient global cerebral ischemia.

Editorial

Toomasian, J. — Tue, 04 Aug 2009 03:49:00 PDT

Successful treatment of peripartum cardiomyopathy with extracorporeal membrane oxygenation

Tue, 04 Aug 2009 03:49:00 PDT

A 24-year-old female developed heart failure within four months of delivering her first child. Echocardiogram revealed a moderately dilated left ventricle with severely reduced systolic function. She continued to decompensate, requiring intubation and inotropic support. When the use of an intra-aortic balloon pump failed to stabilize the patient, the decision was made to place her on ECMO. The circuit consisted of a Quadrox D membrane oxygenator and a CentriMag® centrifugal pump. After 11 days of support, the patient met the weaning criteria and was successfully removed from ECMO. She was discharged one month after her admission. The new technology available allows for ECMO to be considered as an earlier option for the treatment and management of these patients as a bridge to recovery.

Commentary on: Successful treatment of peripartum cardiomyopathy with extracorporeal membrane oxygenation

Palanzo, D — Tue, 04 Aug 2009 03:49:00 PDT

First American experience with the Terumo DuraHeartTM left ventricular assist system

Griffith, K, Jenkins, E, Pagani, F. — Tue, 04 Aug 2009 03:49:00 PDT

Since the first implantation of a left ventricular assist system (LVAS) 45 years ago, LVAS therapy has emerged as a viable option for the treatment of advanced heart failure. The current generation of LVASs in clinical evaluation has design features enabling longer and more reliable support durations. We describe the operating characteristics of the DuraHeart^TM LVAS (Terumo Heart, Inc., Ann Arbor, MI). The DuraHeart^TM LVAS is a magnetically-levitated centrifugal pump that began a FDA-approved clinical trial for evaluation of bridge to transplant indication in July of 2008. Magnetic levitation of the spinning-pump impeller is hypothesized to improve long-term mechanical reliability and biological compatibility of the pump. Other design features make the DuraHeart^TM LVAS particularly suited for implantation without cardiopulmonary bypass (CPB). A description of the implant procedure for the first six American implants of the DuraHeart^TM LVAS both on-CPB and off-CPB, including CPB techniques employed, are discussed. While it is still very early in the DuraHeart^TM LVAS experience, the initial outcomes of the first six patient implants would suggest that the device is a safe and effective LVAS.

Commentary on: First American experience with the Terumo DuraHeartTM ventricular assist system

Griffith, K — Tue, 04 Aug 2009 03:49:00 PDT

The relationship between heparin level and activated clotting time in the adult cardiac surgery population

FitzGerald, D., Patel, A, Body, S., Garvin, S — Tue, 04 Aug 2009 03:49:00 PDT

The purpose of this descriptive study was to examine the relationship between heparin levels (HL) determined by heparin protamine titration (HPT) and activated clotting time (ACT) for cardiopulmonary bypass (CPB) in an adult cardiac surgery population. We examined institutional databases for all patients who underwent CPB at a single US academic institution from February 2005 until July 2007. Baseline ACT, predicted and actual heparin dose response (HDR), target and actual ACT, heparin concentration and heparin bolus dose were recorded. We examined the ACT and HL after the initial heparin bolus dose (Post-Hep) and 10 minutes after the initiation of CPB (CPB+10). The Post-Hep and CPB+10 ACT and HL are reported for 3802 patients. The distribution of ACTs for HL of 0.7, 1.4, 2.0, 2.7 and 3.4 units heparin/mL blood at both time points are reported. Additional analysis of the relationship of HL to ACTs of 300, 350, 400 and 480 seconds is also presented.

Commentary on: The relationship between heparin level and activated clotting time in the adult cardiac surgery population

FitzGerald, D — Tue, 04 Aug 2009 03:49:00 PDT

Aprotinin protects the cerebral microcirculation during cardiopulmonary bypass

Ishibashi, N, Iwata, Y, Zurakowski, D, Lidov, H., Jonas, R. — Tue, 04 Aug 2009 03:49:00 PDT

Background and objective: We have previously reported that administration of aprotinin at a single dose protects the cerebral microcirculation. The current study was designed to identify the optimal dose for protecting the cerebral microcirculation with assessment of neurological and behavioral recovery as well as renal function after circulatory arrest and ultra-low-flow bypass. Methods: Twenty-four piglets were randomly assigned to three bypass groups at risk for postoperative cerebral and renal dysfunction. Cerebral microcirculation was assessed by intravital microscopy. Rhodamine-stained leukocytes were observed for adhesion and rolling. Animals were randomized to one of four aprotinin doses. Neurological deficit score, histological score, creatinine and blood urea nitrogen were analyzed, both independently for this study as well as in combination with 50 animals who were studied with the same protocol and near-infrared spectroscopy. Results: There was a dose-dependent relationship, resulting in fewer activated rolling leukocytes with a higher aprotinin dose. Aprotinin dose was an independent predictor of more rapid recovery of neurological and behavioral outcome. We present a linear regression model where aprotinin dose predicts neurological score. Aprotinin had no impact on renal function. Conclusions: Aprotinin reduces cerebral leukocyte activation and accelerates neurologic recovery in a dose-dependent fashion. Aprotinin has no measurable impact on standard indices of renal function in young piglets. The current lack of availability of aprotinin is a serious disadvantage for pediatric patients undergoing cardiopulmonary bypass.

Evaluation of air handling in a new generation neonatal oxygenator with integral arterial filter

Gomez, D, Preston, T., Olshove, V., Phillips, A., Galantowicz, M. — Tue, 04 Aug 2009 03:49:00 PDT

Prime volume of the cardiopulmonary bypass circuit may lead to significant hemodilution and the potential need for blood products for all patients, but may be more critical in the pediatric and, specifically, the neonatal patient. We report on the first use of the Terumo^® CAPIOX^® FX05 (Baby-FX^TM) oxygenator with integral arterial filter, prime volume 43 ml, evaluating performance and air-handling of six Baby-FX^TM versus thirteen Baby-RX^TM oxygenators. The Terumo Baby-FX^TM primes and performs as easily as the Baby-RX^TM series. A significant prime component in the neonatal CPB circuit can be the arterial line filter (ALF). Removal of the ALF may lead to significant reduction in prime volume, decreased exposure to foreign surfaces with subsequent reduction in inflammation, and potential elimination or reduction in blood product exposures.

Commentary on: Evaluation of a new generation neonatal oxygenator with integral arterial filter

Gomez, D — Tue, 04 Aug 2009 03:49:00 PDT

BelmontTM Hyperthermia Pump in the conduct of intra-operative heated chemotherapy

Riley, W — Tue, 04 Aug 2009 03:49:00 PDT

Intra–operative heated chemotherapy (IOHC) has been performed in the Thoracic surgical department of Brigham and Women’s Hospital (BWH, Boston, MA, USA) for over a decade. A "home-grown" system was developed for this purpose with limited improvements made to it through the years. This technology is used for neo-adjuvant therapy in the conduct of extra-pleural pneumonectomy and pleurectomy for treatment of mesothelioma. Improvements to the traditional BWH system were sought due to the hazardous nature of the chemotherapy solution and the relative complexity of the IOHC circuit. Belmont Instrument (Belmont Instrument Corporation, Billerica, MA, USA) applied their proprietary infusion/warming technology to develop the Belmont^TM Hyperthermia Pump. The Hyperthermia Pump was designed to recirculate large volumes of fluid while maintaining perfusate temperatures up to 46oC at a flow rate of up to 750 ml/min. Approval from the FDA for clinical use of this device was granted June 2007. Parameters were defined and investigated to determine if the Hyperthermia Pump would meet or exceed the performance characteristics of the traditional BWH system. Our investigation resulted in the replacement of the traditional BWH circuit. The Belmont^TM Hyperthermia Pump is a compact, easy to use, extremely safe means to deliver intra-operative hyperthermic chemotherapy in the conduct of surgical treatment of mesothelioma.

Commentary on: BelmontTM Hyperthermia Pump in the conduct of intraoperative heated chemotherapy

Riley, W — Tue, 04 Aug 2009 03:49:00 PDT

Continuous selective bilateral antegrade cerebral perfusion through anomalous innominate artery for repair of root, ascending aortic and arch aneurysm - challenges, vagaries and opportunities of bovine arch variant anatomy and review of literature

Kaul, P, Javangula, K, Ganti, S, Balaji, S, Sivananthan, M, Gough, M, Lindsay, S — Tue, 04 Aug 2009 03:49:00 PDT

We describe the repair of a root, ascending aortic and arch aneurysm in a 69-year-old man with a bioprosthetic Shelhigh conduit and cylinder, employing continuous bilateral antegrade cerebral perfusion through an anomalous innominate artery with a bovine arch variant anatomy. The origin of both the innominate artery and the left common carotid artery from a common stem from the arch in this bovine arch variant puts the whole cerebral circulation at risk, on one hand, yet provides an opportunity of continuous bilateral antegrade cerebral perfusion through the right brachial, right axillary, right subclavian or innominate artery, during arch reconstruction under lower body, deep hypothermic circulatory arrest. Safety and adequacy of selective cerebral perfusion through the right axillary artery in patients with normal arch vessel origin depends on an intact circle of Willis. In this bovine arch variant, both cerebral hemispheres can be perfused through the right brachial, right axillary, right subclavian or the innominate artery, independent of the integrity of the circle of Willis, because of the origin of the left common carotid artery from the innominate artery, except for the area supplied by the left vertebral artery. Although this is the first report of innominate artery perfusion for arch reconstruction for aneurysm in a bovine arch variant, we believe the method described has important implications for cerebral protection in light of the generally reported incidence of bovine arch from 13 to 35 percent.

Bioline(R) heparin-coated ECMO with bivalirudin anticoagulation in a patient with acute heparin-induced thrombocytopenia: the immune reaction appeared to continue unabated

Pappalardo, F, Maj, G, Scandroglio, A, Sampietro, F, Zangrillo, A, Koster, A — Tue, 04 Aug 2009 03:49:00 PDT

Heparin-induced thrombocytopenia (HIT) is a serious, antibody-mediated complication of heparin which significantly confers risks of thrombosis and devastating outcomes. Once diagnosed, it requires immediate cessation of heparin and therapy with an alternative anticoagulant. No data are available in the literature on the pathophysiology and clinical implications of performing prolonged extracorporeal membrane oxygenation with a heparin-coated system in a patient with acute HIT treated with bivalirudin.

Renal dysfunction in cardiac surgery: identifying potential risk factors

Barnum, J., Sistino, J. — Tue, 04 Aug 2009 03:49:00 PDT

Aprotinin has been associated with increased renal failure and mortality when used in cardiac surgery. The purpose of this retrospective study was to compare the incidence of renal failure and mortality in our patient population to the published rates, accounting for risk factors associated with renal failure. After IRB approval; using the STS Database and cardiopulmonary bypass pump records, a total of 2292 cardiac patients were identified from January 2004 through June 2008. Forty-nine patients were excluded because they were on renal dialysis preoperatively. There were 1226 coronary artery bypass patients. Patients were separated into groups, according to which antifibrinolytic agent was used. This study included a total of 716 patients, divided into three groups; aprotinin (n = 436), tranexamic acid (n = 61), and off-pump coronary artery bypass (OPCAB) (n = 219). Epsilon aminocaproic acid (AMICAR) was given by the anesthesiologist to the majority of the remaining 510 patients and was not recorded on the bypass record. Therefore, patients given AMICAR were not included in this study. Outcomes included renal dialysis after surgery and mortality. Risk factors were identified and compared to patients in a study published by Mangano in the New England Journal of Medicine (N Engl J Med 2006; 354: 353–365). Aprotinin vs. control group showed no significant difference in risk factors for diabetes mellitus, hypertension, creatinine level above 1.3 mg/dl, or low ejection fraction. The percentage of patients requiring renal dialysis and mortality was less in Medical University of South Carolina (MUSC) patients than the other published study. Overall, the patients in the MUSC study had greater risk factors for renal failure, with the exception of patients with preoperative serum creatinine of >1.3 mg/dl (8.3 vs. 15.1%). This study does not show the same risk for renal failure associated with aprotinin that has been published elsewhere.

Commentary on: Renal dysfunction in cardiac surgery: identifying potential risk factors

Barnum, J — Tue, 04 Aug 2009 03:49:00 PDT

Editorial

Punjabi, M. P. P — Tue, 30 Jun 2009 07:06:09 PDT

Bivalirudin anticoagulation during cardiac surgery: a single-center experience in 141 patients

Koster, A, Buz, S, Krabatsch, T, Yeter, R, Hetzer, R — Tue, 30 Jun 2009 07:06:09 PDT

The feasibility of bivalirudin for anticoagulation during cardiac surgery has been confirmed in four multicenter clinical trials. Here, we report our single-center experience with bivalirudin anticoagulation in "on-pump" and "off-pump" cardiac surgery in a large number of patients with and without heparin antibodies. Data of patients who underwent cardiac surgery with bivalirudin anticoagulation between 06/2003 and 12/2007 at our institution were reviewed. Assessment included procedural success, blood loss, transfusion requirements, re-exploration rates and drug-related complications during the procedures. There were 141 patients treated with bivalirudin, of whom 40 had heparin antibodies. In 26 patients, "off-pump" coronary artery bypass grafting was performed and the remaining 115 patients had surgery with cardiopulmonary bypass (CPB). The procedural success rate after 7 days and after 30 days was 99.4%. The mean blood loss after "off-pump" surgery was 833 ± 310 ml, with a transfusion rate of 30%. The mean blood loss after "on-pump" surgery was 750 ± 494 ml, with a transfusion rate of 56%. Two patients needed re-exploration due to persistent hemorrhage. Overall transfusion rates were increased in patients with heparin antibodies. The current investigation demonstrates that, in experienced hands, bivalirudin anticoagulation can be performed with excellent procedural success and low complication rates during "on-pump" and "off-pump" cardiac surgery. Recent problems associated with the production of heparin have emphasized the urgent need for an alternative for use beyond the limited indication of heparin-induced thrombocytopenia.

Clinical experience with a novel endotoxin adsorbtion device in patients undergoing cardiac surgery

Blomquist, S, Gustafsson, V, Manolopoulos, T, Pierre, L — Tue, 30 Jun 2009 07:06:09 PDT

Endotoxaemia is thought to occur in cardiac surgery using extracorporeal circulation (ECC) and a positive correlation has been proposed between the magnitude of endotoxaemia and risk for postoperative complications. We studied the effects of a new endotoxin adsorber device (Alteco® LPS adsorber) in patients undergoing cardiac surgery with ECC, with special reference to safety and ease of use. Fifteen patients undergoing coronary artery bypass and/or valvular surgery were studied. In 9 patients, the LPS Adsorber was included in the bypass circuit between the arterial filter and the venous reservoir. Flow through the adsorber was started when the aorta was clamped and stopped at the end of perfusion. Flow rate was kept at 150 ml/min. Six patients served as controls with no adsorber in the circuit. Samples were taken for analysis of endotoxin, TNF, IL-1ß and IL-6 as well as complement factors C3, C4 and C1q. Whole blood coagulation status was evaluated using thromboelastograpy (TEG) and platelet count. No adverse events were encountered when the adsorber was used in the circuit. Blood flow through the device was easily monitored and kept at the desired level. Platelet count decreased in both groups during surgery. TEG data revealed a decrease in whole blood clot strength in the control group while it was preserved in the adsorber group. Endotoxin was detected in only 2 patients and IL-1ß in 4 patients. IL-6 decreased in both groups whereas no change in TNF concentrations was found. C3 fell in both groups, but no changes wer found in C4 and C1q. The Alteco® LPS adsorber can be used safely and is easy to handle in the bypass circuit. No complications related to the use of the adsorber were noted. The intended effects of the adsorber, i.e. removal of endotoxin from the blood stream could not be evaluated in this study, presumably due to the small number of patients and the relatively short perfusion times.

Bicarbonate-buffered ultrafiltration during pediatric cardiac surgery prevents electrolyte and acid-base balance disturbances

Tue, 30 Jun 2009 07:06:09 PDT

Pediatric cardiopulmonary bypass is still a challenge because of electrolyte disturbances and inflammation. Many investigations deal with different types of hemofiltration to reduce these potentially harmful side effects. We tested the hypothesis of whether bicarbonate-buffered hemofiltration of the priming solution minimizes electrolyte and acid-base disturbances during the initiation of cardiopulmonary bypass and whether bicarbonate-buffered hemofiltration performed during cardiopulmonary bypass could reduce cytokine levels. Twenty children younger than 2 years of age (mean age 166 ± 191 days; mean weight 6.42 ± 3.22 kg) scheduled for pediatric cardiac surgery with cardiopulmonary bypass were enrolled in this prospective clinical study. Cardiopulmonary bypass circuits were primed with a bicarbonate-buffered hemofiltration solution, gelatin and 1 unit of packed red blood cells. The priming was hemofiltered using an ultrahemofilter until approximately 1000 mL of ultrafiltrate was restored with the buffered solution. Further hemofiltration was performed throughout the whole bypass time, especially during rewarming. Blood gas analyses and inflammatory mediators were monitored during the operation. Blood gas analysis results after initiation of cardiopulmonary bypass and throughout the entire study remained within the physiologic ranges. Even potassium decreased from 4.0 ± 0.3 to 3.4 ± 0.4 mmol.l^–1 after initiation of cardiopulmonary bypass. Plasma levels of tumor necrosis factor alpha decreased significantly (47 ± 44 vs. 24 ± 21 pg.mL^–1) whereas complement factor C3a (5.0 ± 2.9 vs. 16.8 ± 6.6 ng.mL^–1) and interleukin-6 (7.3 ± 15.2 vs. 110 ± 173 pg.mL^–1) increased despite hemofiltration. In conclusion, this study shows that bicarbonate-buffered ultrafiltration is an efficient, simple and safe method for performing hemofiltration, both of the priming solution and during the entire bypass time. The use of a physiological restitution solution prevents electrolyte and acid-base balance disturbances. The elimination of inflammatory mediators seems to be as effective as other ultrafiltration methods.

Propofol requirement titrated to bispectral index: a comparison between hypothermic and normothermic cardiopulmonary bypass

Mathew, P., Puri, G., Dhaliwal, R. — Tue, 30 Jun 2009 07:06:09 PDT

Though propofol requirement is expected to decrease during cardiopulmonary bypass (CPB), a few studies have failed to demonstrate this. The factors affecting pharmacokinetics of propofol and, therefore, the requirement, are different during hypothermic and normothermic CPB. We evaluated and compared the requirement of propofol during hypothermic and normothermic CPB. Fifty adult patients scheduled for elective cardiac surgery on CPB were recruited and randomly allocated into hypothermic CPB (28–30⁰ C) (Group H) and normothermic CPB (35–37⁰ C) (Group N) groups. Patients were induced and maintained with propofol titrated to maintain a target bispectral index (BIS) of 50 ± 10. Propofol requirement (mean ± SD) was similar in normothermic and hypothermic groups, both before CPB (4.9 ± 1.5 mg.kg^–1hr^–1 in Group N, 4.6 ± 1.5 mg.kg^–1hr^–1 in Group H) and after cessation of bypass (p > 0.05) (4.6 ± 1.8 mg.kg^–1hr^–1 in Group N and 4.3 ± 1.7 mg.kg^–1hr^–1 in Group H). CPB significantly reduced (p < 0.001) propofol requirements in both arms of the study (Group N: 2.9 ± 1.4 mg.kg^–1hr^–1and Group H: 1.3 ± 0.7 mg.kg^–1hr^–1). This reduction was more pronounced in the hypothermic group (p < 0.001). The BIS (median ± inter quartile range) remained constant during normothermic CPB (50 ± 8.8), but declined significantly during hypothermic CPB (41 ± 5.6) despite decreased usage of propofol during hypothermia. No patient had recall of intra-operative events. CPB decreases the magnitude of propofol requirements and the effect of hypothermic CPB is significantly more than that of normothermic CPB.

Aortic valve endocarditis with aortic wall thickening requires close follow-up for a possible abscess formation

Yeter, E, Bayram, N., Akcay, M, Keles, T, Durmaz, T — Tue, 30 Jun 2009 07:06:09 PDT

A 67-year-old woman was admitted with aortic valve endocarditis and aortic wall thickening (AWT). Physical examination and laboratory findings yielded infective endocarditis. Echocardiography revealed several small vegetations on the aortic valve, leading to moderate aortic insufficiency together with a small ventricular septal defect. We also became aware of the AWT on and over the aortic root by transesophageal echocardiography (Figure 1). At the one month follow-up period, we also noticed an abscess formation originating from the AWT, which grew into a mature abscess form, day by day (Figure 2). The aortic valve endocarditis, with destruction of the aortic annulus and abscess formation, in this patient, is considered as a grave condition which, essentially, requires an aggressive combined surgical and medical approach. We would like to intimate here with this patient that AWT needs to be considered seriously important in aortic valve endocarditis and, even if the detected vegetations are small, a close follow-up for a possible abscess formation is essential.

Beneficial effects of modern perfusion concepts in aortic valve and aortic root surgery

Kutschka, I, Skorpil, J, El Essawi, A, Hajek, T, Harringer, W — Tue, 30 Jun 2009 07:06:09 PDT

Minimized perfusion circuits (MPC) were found to reduce side effects of standard extracorporeal circulation (ECC). We evaluated the safety and efficacy of the ROCsafe^TM MPC for aortic valve and aortic root surgery. One hundred and seventy patients were randomized for surgery using either MPC [n = 85, 30 female/55 male, mean age: 69.8 ± 11.8 years; aortic valve replacement (AVR): n = 40; AVR + coronary artery bypass graft (CABG): n = 31; David operation: n = 3; aortic root replacement (ARR): n = 11] or ECC [n = 85, 29 female/56 male, mean age: 67.7 ± 9.5 years; AVR: n = 39; AVR+CABG: n = 35, David operation: n = 2; ARR: n = 9]. Neurological status, length of ICU stay, C-reactive protein (CRP), blood count, transfusion requirements and bleeding volume were analyzed. The MPC system provided ultrasound-controlled de-airing. A small roller pump and a flexible reservoir were used for left ventricular venting. As a control, we used a standard ECC with cardiotomy suction and hard-shell reservoir. Cross-clamp time (MPC: 76.5 ± 29.5; ECC: 79.0 ± 34.0 min) and bypass time (MPC: 103.0 ± 37.9; ECC: 106.9 ± 44.9 min) were comparable between groups. Transfusion requirements (red blood cells: MPC: 1.5 ± 1.5 vs. ECC: 2.2 ± 2.1 units [p = 0.05], frozen plasma: MPC: 1.2 ± 1.8 vs. ECC: 1.9 ± 2.4 units [p = 0.03]), postoperative bleeding (MPC: 521 ± 283 vs. ECC: 615 ± 326 ml/24 h, p = 0.09) were lower using MPC. ICU stay was shorter with MPC (1.6 ± 1.6 days) compared to ECC (2.4 ± 2.8 days, p = 0.001). One stroke occurred in each group. The ROCsafe^TM MPC provides safe circulatory support for a wide range of aortic valve surgeries. Transfusion requirements, postoperative bleeding and length of ICU stay were markedly reduced compared to standard extracorporeal perfusion.

Extracorporeal membrane oxygenation support for 59 days without changing the ECMO circuit: a case of Legionella pneumonia

Tue, 30 Jun 2009 07:06:09 PDT

We report the successful use of veno-venous extracorporeal membrane oxygenation (ECMO) in a 53-year-old patient with Legionella pneumonia and acute respiratory distress syndrome (ARDS) with severe barotraumas. The patient was supported for 59 days without any changes in the ECMO circuit. This is probably the longest support ever reported using the same oxygenator.

Successful use of a new hand-held ECMO system in cardiopulmonary failure and bleeding shock after thrombolysis in massive post-partal pulmonary embolism

Arlt, M, Philipp, A, Iesalnieks, I, Kobuch, R, Graf, B. — Tue, 30 Jun 2009 07:06:09 PDT

Massive pulmonary embolism (PE) leads to cardiogenic shock and is associated with mortality rates of up to 75%.1 We report on a 27-year-old mother in childbirth who developed a massive post-partal PE and cardiac arrest. Despite mechanical resuscitation, return of spontaneous circulation (ROSC) could not be achieved. After systemic thrombolysis, ROSC returned, but cardiopulmonary failure was persisting, complicated by massive bleeding shock. By using a newly developed, hand-held ECMO system, systemic blood flow and oxygenation were restored and emergency medical services for advanced surgical treatment (hysterectomy and pulmonary embolectomy) were possible. The patient recovered completely. We assume that this newly developed hand-held ECMO device enables rapid onset mechanical life support and improves the prognosis of patients in fatal conditions.

Case report: plasma leakage in a polymethylpentene oxygenator during extracorporeal life support

Puis, L, Ampe, L, Hertleer, R — Tue, 30 Jun 2009 07:06:09 PDT

Plasma leakage is a phenomenon which has almost completely disappeared since the introduction of plasma-tight polymethylpentene (PMP) fibers in oxygenators used for extracorporeal life support (ECLS). We describe here a case of ECLS which was affected by the rapid occurrence of plasma leakage in oxygenators with polymethylpentene fibers. To our knowledge, this is the first report of the phenomenon since the introduction of this new generation of oxygenators.

Editorial

Mulholland, J. — Tue, 19 May 2009 06:25:07 PDT

Cardiopulmonary bypass and edema: physiology and pathophysiology

Hirleman, E, Larson, D. — Tue, 19 May 2009 06:25:07 PDT

Edema is a common morbidity following cardiopulmonary bypass (CPB) and can result in injury to many organs, including the heart, lungs, and brain. Generalized edema is also common and can lead to increased post-operative hospital stay and other morbidities. Pediatric patients are more susceptible to post-CPB edema and the consequences are more severe for this population. Hemodilution and systemic inflammatory responses are two suspected causes of CPB-related edema; however, the mechanisms involved are far from understood. Also, the common strategies to improve edema have not been completely successful and there is a need for new strategies at maintaining a fluid balance of patients as close to physiological as possible, especially for pediatric patients. An integrative approach to understanding edema is necessary as the forces involved in fluid homeostasis are dynamic and interdependent. Therefore, this review will focus on the physiology of fluid homeostasis and the pathologies of fluid shifts during CPB which lead to general edema as well as tissue-specific edema.

Cardiopulmonary bypass management and acute renal failure: risk factors and prognosis

Tue, 19 May 2009 06:25:07 PDT

The aim of the study was to investigate if acute renal failure (ARF) following cardiac surgery is influenced by CPB perfusion pressure and to determine risk factors of ARF. Our research consisted of two studies. In the first study, 179 adult patients with normal preoperative renal function who had been subjected to cardiac surgery on CPB were randomized into three groups. The mean perfusion pressure (PP) during CPB in Group 65 (68 patients) was 60–69.9 mmHg, in Group 55 (59 patients) – lower than 60 mmHg and in Group 75 (52 patients) – 70 mmHg and higher. We have analyzed postoperative variables: central venous pressure, the need for diuretics, urine output, fluid balance, acidosis, potassium level in blood serum, the need for hemotransfusions, nephrological, cardiovascular and respiratory complications, duration of artificial lung ventilation, duration of stay in ICU and in hospital, and mortality. In the second study, to identify the risk factors for the development of ARF following CPB, we retrospectively analysed data of all 179 patients, divided into two groups: patients who developed ARF after surgery (group with ARF, n = 19) and patients without ARF (group without ARF, n = 160). We found that urine output during surgery was statistically significantly lower in Group 55 than in Groups 65 and 75. The incidence of ARF in the early postoperative period did not differ among the groups: it developed in 6% of all patients in Group 65, 4% in Group 55 and 6% in Group 75. There were no differences in the rate of other complications (cardiovascular, respiratory, neurological disorders, bleeding, etc) among the groups. There were 19 cases of ARF (10.6%), but none of these patients needed dialysis. We found that age (70.0 ± 7.51 vs. 63.5 ± 10.54 [standard deviation, SD], P = 0.016), valve replacement and/or reconstruction surgery (57.9% vs. 27.2%, P = 0,011), combined valve and CABG surgery (15.8% vs. 1.4%, P = 0.004), duration of CPB (134.74 ± 62.02 vs. 100.59 ± 43.99 min., P = 0.003) and duration of aortic cross-clamp (75.11 ± 35.78 vs. 53.45 ± 24.19 min., P = 0.001) were the most important independent risk factors for ARF. Cardiopulmonary bypass perfusion pressure did not cause postoperative renal failure. The age of patient, valve surgery procedures, duration of cardiopulmonary bypass and duration of aorta cross-clamp are potential causative factors for acute renal failure after cardiac surgery.

The effect of hemodilution during normothermic cardiac surgery on renal physiology and function: a review

Vermeer, H, Teerenstra, S, de Sevaux, R., van Swieten, H., Weerwind, P. — Tue, 19 May 2009 06:25:07 PDT

Although the definitions of renal dysfunction vary, loss of renal function is a common complication following cardiac surgery using cardiopulmonary bypass (CPB). When postoperative dialysis is required, mortality is approximately 50%. CPB-accompanied hemodilution is a major contributing factor to renal damage as it notably reduces oxygen delivery by reducing the oxygen transport capacity of the blood as well as disturbing the microcirculation. To minimize hypoxemic damage during CPB, lowering of body temperature is applied to reduce the patient’s metabolic rate. At present, however, temperature management during elective adult cardiac surgery is shifting from moderate hypothermia to normothermia. To determine whether the currently accepted levels of hemodilution during CPB can suffice the normothermic patient’s high oxygen demand, we focused this study on renal physiology and postoperative renal function. Hemodilution reduces the capillary density through a diminished capillary viscosity, thereby, redistributing blood from the renal medulla to the renal cortex. As the physiology of the renal medulla makes it a hypoxic environment, this part of the kidney appears to be especially at risk for hypoxic damage caused by a hemodilution-induced lowered oxygen transport and oxygen delivery. In addition, hemodilution is also likely to disturb the hormonal systems regulating renal blood distribution. Clinical studies, mostly of retrospective or observational nature, show that perioperative nadir hematocrit levels lower than approximately 24% are associated with an increased risk to develop postoperative renal failure. A better comprehension of the cause-and-effect relation between low perioperative hematocrits and loss of postoperative renal function may enable more effective renal protective strategies.

Impact of cardiopulmonary bypass on peripheral tissue metabolism and microvascular blood flow

Tue, 19 May 2009 06:25:07 PDT

The aim of this study was to monitor and compare the changes in metabolism and blood flow in the skeletal muscles during cardiac operations performed with cardiopulmonary bypass (CPB) and operations without CPB (off-pump) by means of interstitial microdialysis (Figure 1). Surgical revascularization, coronary artery bypass grafting (CABG), was performed in 40 patients randomized to two groups. Twenty patients (On-Pump Group) were operated on using CPB, 20 patients (Off-Pump Group) were operated on without CPB. Interstitial microdialysis was performed by 2 probes of a CMA 60 (CMA Microdialysis AB, Solna, Sweden) inserted into the patient’s deltoid muscle. Microdialysis measurements were performed at 30-minute intervals. Glucose, lactate, pyruvate and glycerol as markers of basic metabolism and tissue perfusion were measured in samples from the first probe, using a CMA 600 Analyzer (CMA Microdialysis AB). Blood flow through the interstitium was monitored by means of dynamic microdialysis of ethanol as a flow-marker in the dialysates taken from the second probe (ethanol dilution technique). Results in both the groups were statistically processed and compared. Both the groups were similar in respect of preoperative characteristics. Dynamic changes of interstitial concentrations of the measured analytes were found in both the patient groups (on-pump vs. off-pump) during the operation. There was no significant difference in dialysate concentrations of glucose and lactate between the groups. Significant differences were detected in pyruvate and glycerol interstitial concentrations, lactate/pyruvate ratio and lactate/glucose ratio between the on-pump vs. off-pump patients. In the Off-Pump Group, pyruvate concentrations were higher and the values of concentrations of glycerol lower. The lactate/pyruvate ratio and the lactate/glucose ratio, indicating the aerobic and anaerobic tissue metabolism status, were lower in the Off-Pump Group. There was no significant difference in dialysate concentrations of ethanol as a flow-marker during the surgery in either of the groups. There was no statistically significant difference between the groups (On-Pump Group vs. Off-Pump Group) comparing the postoperative clinical outcome (ICU stay, ventilation duration, length of hospital stay). The dynamic changes in the interstitial concentrations of the glucose, glycerol, pyruvate and lactate were found in both the groups of patients (On-Pump Group and Off-Pump Group), but there was no difference in local blood flow when the ethanol dilution technique was used. These results showed significantly higher aerobic metabolic activity of the peripheral tissue of patients in the Off-Pump Group vs. the On-Pump Group during the course of cardiac revascularization surgery. Results suggest that extracorporeal circulation, cardiopulmonary bypass, compromises peripheral tissue (skeletal muscles) energy metabolism. These changes have no impact on the postoperative clinical outcome; no significant difference between the groups was found.

Influence of venous reservoir level on microbubbles in cardiopulmonary bypass

Nielsen, P., Funder, J., Jensen, M., Nygaard, H — Tue, 19 May 2009 06:25:07 PDT

Patients undergoing open-heart surgery may, post-operatively, suffer from neurological disorders due to microbubbles created during extracorporeal circulation. Venous air is not completely removed in open hard-shell venous reservoirs. We, therefore, investigated the relationship between venous reservoir blood level and the amount of microbubbles in different commercially available reservoirs for comparison and determination of safe level. An in vitro flow loop with a heart-lung machine was used to compare three different reservoirs (Maquet, Sorin and Medtronic) at different levels. Microbubbles were measured after the reservoir and after the arterial filter with a GAMPT BCC200 detector. Microbubble count and volume were significantly higher with decreasing reservoir level (p = 0.014), but not as much as earlier studies have shown. Reducing the level from 1000 ml to 250 ml resulted in a 12.4% increase in bubble volume after the reservoir and 40.2% after the arterial filter. There was an almost linear trend towards more bubble volume with decreasing reservoir level (R2 = 0.98-0.83). There was a significant difference in microbubbles between the 3 tested reservoirs, up to 32.6%, p < 0.001 measured after the reservoir. Bubble volume from the Sorin reservoir was markedly lower after the arterial filter than from the Medtronic and Maquet reservoirs (up to 60 times p < 0.001). A lower reservoir level results in a moderate rise in microbubbles passing the reservoir. The minimum levels recommended by the manufacturers are safe. There was a significant difference in bubbles between the different reservoirs, especially after the arterial filter.

Aprotinin concentration varies significantly according to cardiopulmonary bypass conditions

Okamura, T, Ishibashi, N, Iwata, Y, Zurakowski, D, Jonas, R. — Tue, 19 May 2009 06:25:07 PDT

Although aprotinin is partially excreted unchanged in the urine, its primary site of metabolism is in the renal lysosomes following proximal tubule resorption. This study tested the hypothesis that plasma aprotinin concentration varies with cardiopulmonary bypass conditions. Thirty-two piglets (weight 13.2 ± 1.9 kg) received an aprotinin initial dose of 30,000 KIU/kg, a maintenance infusion of 10,000 KIU/kg/h, with a cardiopulmonary bypass (CPB) prime of 30,000 KIU/kg. Aprotinin infusion was terminated at the end of CPB and stopped during hypothermic circulatory arrest (HCA). Piglets were randomized to four groups (n = 8 per group): HCA, 60-minute period at 15°C; low-flow (LF), 10 mL/kg/min low-flow CPB at 25°C; full flow (FF), full flow CPB at 37°C; control at 37°C without CPB. Blood samples were collected at 7 time points: after induction of anesthesia (baseline), after initial dose, 10, 50 and 115 min after start of CPB, just before end of CPB and 30 min after CPB. Plasma aprotinin levels were determined by modified functional assays. Aprotinin levels in the control group were significantly lower at each point after start of CPB than all groups with CPB (p < .001). In particular, during the reperfusion period, aprotinin levels were higher in HCA and LF groups than FF group (p < .05). Throughout CPB, aprotinin levels in the HCA group remained unchanged (p > .40). Bypass conditions affect plasma aprotinin concentration. Recently reported renal and neurological complications with aprotinin use during CPB may reflect excessive dosing and point to the need for real-time monitoring.

Outcome after coronary artery bypass surgery with miniaturized versus conventional cardiopulmonary bypass

Tue, 19 May 2009 06:25:07 PDT

We have reviewed the results of our experience with the use of miniaturized (Mini-CPB) versus conventional (C-CPB) cardiopulmonary bypass in coronary artery bypass surgery (CABG). This study included 365 patients who underwent CABG with C-CPB and 101 patients with Mini-CPB. In-hospital mortality was lower in the C-CPB group (1.4% vs. 3.0%, P = 0.38). A better, but not statistically significant, immediate outcome was observed in the C-CPB group as indicated by a shorter length of stay in the intensive care unit as well as a lower incidence of combined adverse end-point. However, this was probably due to significantly higher operative risk in the Mini-CPB group (logistic EuroSCORE: 8.5 ± 10.0 vs. 4.6 ± 7.1, P < 0.0001). Seventy-seven propensity score-matched pairs had similar immediate postoperative results after Mini-CPB and C-CPB (30-day mortality: 1.3% vs. 1.3%; stroke: 0% vs. 0%; intensive care unit stay ≥5 days: 6.5% vs. 9.1%; combined adverse events: 14.3% vs. 11.7%). Mini-CPB achieves similar results to C-CPB in patients undergoing isolated CABG. The potential efficacy of Mini-CPB is expected to be more evident in high-risk patients or in complex cardiac surgery requiring much longer cardiopulmonary perfusion.

Does an allergy to fish pre-empt an adverse protamine reaction? A case report and a literature review

Collins, C, O'Donnell, A — Tue, 19 May 2009 06:25:07 PDT

The operating theatre exposes patients to myriad potential agents which could result in a life-threatening anaphylactic reaction. Anaesthetic drugs, blood products, and latex are only some of the possible allergens. Reactions are deemed to be anaphylactic when immediate sensitivity is combined with cardiovascular collapse. A patient who had a known allergy to shellfish presented for first time cardiopulmonary bypass. The perfusion team were concerned that there was a realistic possibility that an adverse reaction to protamine could occur. Anaphylactic reactions to protamine in patients allergic to fish have been reported. The anaesthetic team were informed and the necessary precautions taken. We report on the outcome for our patient and also discuss other risk factors and the types of reactions that can result when an adverse reaction to protamine occurs.