Perfusion current issue

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.