Veno-venous extracorporeal membrane oxygenation using a double-lumen bi-caval cannula for severe respiratory failure post total artificial heart implantation.

We report a unique utilization of a double-lumen, bi-caval Avalon cannula for veno-venous (VV) extracorporeal membrane oxygenation (ECMO) during placement of a total artificial heart (TAH, SynCardia, Tucson, AZ). A 22-year-old female with post-partum cardiomyopathy was rescued on veno-arterial (VA) ECMO because of cardiogenic shock. The inability to wean ECMO necessitated implantation of the TAH as a bridge to transplant. In addition, the patient continued to have respiratory failure and concomitant VV ECMO was planned with the implant. During TAH implantation, the Avalon cannula was placed percutaneously from the right internal jugular vein into the inferior vena cava (IVC) under direct vision while the right atrium was open. During VV ECMO support, adequate flows on both ECMO and TAH were maintained without adverse events. VV ECMO was discontinued, without reopening the chest, once the patient's respiratory failure improved. However, the patient subsequently developed a profound respiratory acidosis and required VV ECMO for CO2 removal. The Avalon cannula was placed in the femoral vein to avoid accessing the internal jugular vein and risking damage to the TAH. The patient's oxygenation eventually improved and the cannula was removed at the bedside. The patient was supported for 22 days on VV ECMO and successfully weaned from the ventilator prior to her orthotropic heart transplantation.

A cost-reducing extracorporeal membrane oxygenation (ECMO) program model: a single institution experience.

BACKGROUND: The worldwide demand for ECMO support has grown. Its provision remains limited due to several factors (high cost, complicated technology, lack of expertise) that increase healthcare cost. Our goal was to assess if an intensive care unit (ICU)-run ECMO model without continuous bedside perfusionists would decrease costs while maintaining patient safety and outcomes. METHOD: A new ECMO program was implemented in 2010, consisting of dedicated ICU multidisciplinary providers (ICU-registered nurses, mid-level providers and intensivists). In year one, we introduced an education platform, new technology and dedicated space. In year two, continuous bedside monitoring by perfusionists was removed and new management algorithms designating multidisciplinary providers as first responders were established. The patient safety and cost benefit from the removal of the continuous bedside monitoring of the perfusionists of this new ECMO program was retrospectively reviewed and compared. RESULTS: During the study period, 74 patients (28 patients in year 1 and 46 patients in year 2) were placed on ECMO (mean days: 8 ± 5.7). The total annual hospital expenditure for the ECMO program was significantly reduced in the new model ($234,000 in year 2 vs. $600,264 in year 1), showing a 61% decrease in cost. This cost decrease was attributed to a decreased utilization of perfusion services and the introduction of longer lasting and more efficient ECMO technology. We did not find any significant changes in registered nurse ratios or any differences in outcomes related to ICU safety events. CONCLUSION: We demonstrated that the ICU-run ECMO model managed to lower hospital cost by reducing the cost of continuous bedside perfusion support without a change in outcomes.

Successful management of bleeding complications in patients supported with extracorporeal membrane oxygenation with primary respiratory failure.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) is a lifesaving procedure in patients with severe respiratory insufficiency failing conventional support. Bleeding complications are common due to the necessity for anticoagulation and circuit-related factors. METHODS: A retrospective review was conducted in patients requiring ECMO for respiratory failure from 7/2010 to 6/2011 to identify episodes of major bleeding, bleeding management and outcomes. RESULTS: Twenty-one patients were supported with ECMO during the study although five experienced massive bleeding related to chest tube insertion, jejunal arterio-venous malformations, distal perfusion cannula dislodgement and ventricular rupture. Patients required aggressive resuscitation or endoscopic or operative intervention, totaling 28 procedures. There were no instances of dehiscence, infection or sepsis related to interventions. Anticoagulation was stopped six hours before and restarted 24 hours after major interventions, with no thrombotic or neurologic complications. All patients weaned off ECMO were discharged. CONCLUSIONS: ECMO bleeding complications can be managed successfully via surgical and endoscopic approaches in this high-risk population.

A Population Pharmacokinetic Model for Vancomycin in Adult Patients Receiving Extracorporeal Membrane Oxygenation Therapy.

The literature on the pharmacokinetics of vancomycin in patients undergoing extracorporeal membrane oxygenation (ECMO) therapy is sparse. A population pharmacokinetic (PK) model for vancomycin in ECMO patients was developed using a nonlinear mixed effects modeling on the concentration-time profiles of 14 ECMO patients who received intravenous vancomycin. Model selection was based on log-likelihood criterion, goodness of fit plots, and scientific plausibility. Identification of covariates was done using a full covariate model approach. The pharmacokinetics of vancomycin was adequately described with a two-compartment model. Parameters included clearance of 2.83 L/hr, limited central volume of distribution 24.2 L, and low residual variability 0.67%. Findings from the analysis suggest that standard dosing recommendations for vancomycin in non-ECMO patients are adequate to achieve therapeutic trough concentrations in ECMO patients. This further shows that ECMO minimally affects the PK of vancomycin in adults including in higher-weight patients.

Cognitive function in patients with symptomatic dilated cardiomyopathy before and after cardiac transplantation.

Pre- and postoperative cognitive performance of candidates for heart transplantation was examined by means of an extensive battery of neuropsychological measures. A total of 54 patients completed the preoperative cognitive protocol, 20 of whom also completed postoperative testing. Age (less than 50 or greater than or equal to 50 years of age) and the primary cause of cardiac deterioration (idiopathic, ischemic disease or rheumatic/congenital defects) were the major classification variables. The main findings of this study were: 1) Preoperative neuropsychological measures revealed a high frequency of impaired performance, particularly in measures of memory, higher level processing of information and motor speed. A pattern consistent with diffuse rather than focal or lateralized cerebral deficits was observed. Significant differences were not found on the basis of the cause of cardiac disease, but some were observed for age (the older group was more impaired). 2) A comparison of pre- and postoperative cognitive scores failed to show significant cognitive improvement despite greatly improved physical health. The cause of cardiac deterioration was not differentially associated with postoperative cognitive performance, and there was equivocal evidence for age effects. These findings may have implications for the selection of transplant recipients and the timing of transplantation surgery.

A shorter hospital stay after cardiac pacemaker implantation.

In an effort to shorten the hospital stay after implantation of a permanent cardiac pacemaker, some physicians have begun performing pacemaker implantation on an ambulatory basis. To assess the potential safety of shortening the duration of hospitalization after pacemaker implantation, we reviewed the complications that occurred in 100 consecutive patients after pacemaker implantation and noted the time after the implantation when the complications occurred. In our study group, all complications that necessitated invasive intervention occurred within 24 hours after the pacemaker implantation. Complications that necessitated noninvasive programming occurred as long as 72 hours after implantation, and all could have been safely corrected at the time of follow-up had the patient been dismissed at the 24-hour period. Although we do not believe that ambulatory pacemaker implantation should be routinely implemented at this time, the practice of dismissing patients at 24 hours after pacemaker implantation and scheduling subsequent outpatient follow-up seems to be safe and effective.

Ischemia of the interventricular septum. A mechanism of right ventricular failure during mechanical left ventricular assist.

Right ventricular failure has been noted in up to 25% of patients requiring a left ventricular assist device. Altered septal motion or function is one proposed mechanism of right ventricular failure during left heart bypass. We studied the effect of regional ischemia and reperfusion of the interventricular septum on right ventricular function during complete left heart bypass. In six calves the septal perforating branches of the proximal left anterior descending coronary artery were isolated for intermittent occlusion. Complete left heart bypass was established with a Pierce-Donachy left ventricular assist device. Right and left ventricular function were studied with two-dimensional echocardiography and with intraventricular pressure monitors. Establishment of left heart bypass did not significantly affect right ventricular developed pressure, right ventricular end-diastolic area, or right ventricular fractional change in area. Left heart bypass significantly (p less than 0.001) decreased percent systolic septal wall thickening. Septal ischemia during left heart bypass resulted in a decrease in right ventricular developed pressure (p = 0.09), significant increase in right ventricular end-diastolic area (p = 0.002) and significant decrease in right ventricular fractional change in area (p less than 0.001), and a further decrease in interventricular septal wall thickening (p = 0.016). The interventricular septum became thin with flattening of its normal contour. Septal reperfusion resulted in right ventricular recovery with significant improvement in all factors (p less than 0.02). Similar results were documented during a second episode of septal ischemia with recovery after septal reperfusion. In some cases, septal ischemia may be an important factor in the development of right ventricular failure during left heart bypass.

The artificial heart in human subjects.

In preparation for clinical implantation of the Utah J-7 pneumatic artificial heart as a permanent cardiac substitute, the device was implanted into five brain-dead human subjects. This report presents our results and details our two most successful trials. Three different surgical implant techniques were utilized in the five subjects. Because of the unique "no risk" situation of the subjects, the function of the artificial heart could be tested in a manner not advisable in patients, but necessary for clinical preparation. The implantable total artificial heart was able to maintain physiological hemodynamics in two subjects for 41 and 72 hours at which time the trials were electively terminated.

Complement activation during cardiopulmonary bypass. Comparison of bubble and membrane oxygenators.

A prospective randomized trial involving 91 patients undergoing cardiopulmonary bypass compared the effects of bubble oxygenators (with and without methylprednisolone sodium succinate) and membrane oxygenators on complement activation and transpulmonary sequestration of leukocytes. Patients were divided as follows: Group I, 30 patients, bubble oxygenator; Group II, 31 patients, bubble oxygenator and methylprednisolone sodium succinate (30 mg/kg); Group III, 30 patients, membrane oxygenator. In Group I, C3a increased from 323 +/- 171 ng/ml during cardiopulmonary bypass to 1,564 +/- 785 ng/ml at 25 minutes after bypass (p less than 0.0001). A significant decrease in C3a was found in Groups II and III compared to Group I (p less than 0.0001). C5a did not change significantly during cardiopulmonary bypass in any group. Reestablishment of pulmonary circulation at the end of bypass produced significant transpulmonary leukocyte sequestration in Group I; the median cell difference was 1,700/microliter. Transpulmonary sequestration was significantly (p less than 0.0001) less in Group II (median cell difference = 200/microliter) and in Group III (median cell difference = 400/microliter) than in Group I. We conclude that cardiopulmonary bypass with a bubble oxygenator alone initiates significantly (p less than 0.0001) more C3a activation and leukocyte sequestration than when methylprednisolone sodium succinate (30 mg/kg) is given 20 minutes before the start of cardiopulmonary bypass with a bubble oxygenator or when a silicone membrane oxygenator is used.

Evidence for complement activation by protamine-heparin interaction after cardiopulmonary bypass.

Complement activation by the alternate pathway has been implicated in the pathophysiology of cardiopulmonary bypass (CPB), and laboratory studies suggest that the complement cascade may be activated by the protamine-heparin complex. To determine if the administration of protamine to patients receiving heparin activates complement, we studied 100 patients undergoing CPB by assaying levels of C3a and C4a (classic pathway) at regular intervals before and after protamine administration. In group I (90 patients), protamine was given at the usual interval (median 5 minutes) after CPB. In group II (10 patients), protamine was withheld until skin closure (median 45 minutes) after CPB. Results demonstrated that C4a was not activated during CPB in either group. After CPB, the C4a level in group I was 459 ng/dl and increased to 1047 ng/dl 10 minutes after protamine administration (p less than 0.001). In group II, the C4a level was 484 ng/dl at the end of CPB and 354 ng/dl 15 minutes later, which corresponds to the value immediately after protamine administration in group I. The delayed administration of protamine in group II caused a significant increase in C4a at the time of skin closure (1090 ng/dl; p less than 0.001). Corresponding results from C3a analysis before and after protamine administration confirmed the activation of complement cascade. Our study provides the first clinical evidence that the protamine-heparin complex activates complement via the classic (C4a) pathway. The hemodynamic effects of protamine after CPB may be related to complement activation.

Heart/heart-lung transplantation. The domino procedure.

Orthotopic heart transplantation has become an accepted therapeutic modality limited only by availability of donor organs. Heart-lung transplantation is also being performed with increasing frequency due to improvements in distant procurement techniques. Although the majority of patients requiring heart-lung transplantation have cardiac dysfunction, there is a subset with no cardiac compromise that can serve as donors of cardiac allografts before heart-lung transplantation. We report a technique for sequential heart/heart-lung transplantation in such a subset of patients.

Prosthetic valve endocarditis with annulus destruction: technique for reconstruction.

When endocarditis involves a mechanical prosthetic aortic valve, it is a certainty that the annulus is destroyed; the pathology may extend to produce aneurysms of the sinuses of Valsalva or progress to fistulization into juxtaposed cardiac chambers or the pericardium. Annular destruction breaks down the framework to which a new prosthesis is anchored; therefore, valve replacement requires the creation of a new annulus. This report describes the technique for reconstructing partial aortoventricular discontinuity caused by annular destruction from prosthetic valve bacterial endocarditis.