Cardiac output determination from endotracheally measured impedance cardiography: clinical evaluation of endotracheal cardiac output monitor.

OBJECTIVES: To evaluate the accuracy, precision, and trending of a new endotracheally sourced impedance cardiography-based cardiac output (CO) monitor (ECOM; ConMed Corp, Irvine, CA). SETTING: Two university hospitals. PARTICIPANTS: Thirty patients scheduled for elective coronary artery bypass graft (CABG) surgery. INTERVENTIONS: All patients received a pulmonary artery catheter (PAC), arterial catheter, endotracheal CO monitor (ECOM), endotracheal intubation, and transesophageal echocardiographic monitoring. ECOM CO was compared with CO measured with pulmonary artery thermodilution, and left ventricular CO measured with transesophageal echocardiography. MEASUREMENTS: One hundred forty-five pairs of triplicate CO measurements using intermittent bolus pulmonary artery thermodilution (TD) and ECOM were compared at 5 distinct time points: postinduction, postinduction passive leg raise, poststernotomy, post-CABG completion, and post-chest closure. Eighty-seven pairs of triplicate CO measurements using transesophageal echocardiography were obtained at 3 time points: postinduction, post-CABG completion, and post-chest closure and compared with ECOM- and PA-derived CO measurements. The measurements at each time point were compared by using Bland-Altman and polar plot analyses. RESULTS: The mean CO ranged from 2.16 to 9.41 L/min. ECOM CO, compared with TD CO, revealed a bias of 0.02 L/min, 95% limits of agreement of -2.26 to 2.30 L/min, and a percent error of 50%. ECOM CO showed trending with TD CO with 91% and 99% of values within 0.5L/min and 1 L/min limits of agreement, respectively. ECOM CO, compared with TEE CO, revealed a bias of -0.25 L/min, 95% limits of agreement of -2.41 to 1.92 L/min, and a percent error of 48%. ECOM CO showed trending with TEE CO with 83% and 95% of values within 0.5L/min and 1 L/min limits of agreement, respectively. CONCLUSION: ECOM CO shows an acceptable bias with wide limits of agreement and a large percent error when compared with TD CO or TEE CO; however, it shows acceptable trending of CO to both modalities in patients undergoing cardiac surgery. Further studies are required to evaluate ECOM in other patient populations and clinical situations.

Novel Use of Cangrelor With Heparin During Cardiopulmonary Bypass in Patients With Heparin-Induced Thrombocytopenia Who Require Cardiovascular Surgery: A Case Series.

Optimal anticoagulation strategy during cardiopulmonary bypass (CPB) remains uncertain in patients with heparin-induced thrombocytopenia (HIT) who require urgent/emergent cardiac surgery. We describe our strategy and experience with utilizing cangrelor in combination with heparin for anticoagulation during CPB in patients with different phases of HIT undergoing a wide range of urgent/emergent cardiovascular surgery. Cangrelor is an intravenous direct-acting P2Y12 platelet receptor antagonist that achieves therapeutic effect and eliminates rapidly. Its antiplatelet activity is unaffected by stagnation of blood, nor is it influenced by patient's sex, age, renal status, or hepatic function. Our institutional alternative intraoperative anticoagulation strategy for HIT patients is to administer cangrelor with a loading dose of 30 µg/kg, followed by continuous infusion of 4 µg/kg/min throughout CPB via a dedicated intravenous access. VerifyNow P2Y12 reaction unit point-of-care assay is utilized to monitor platelet inhibition throughout surgery. Cangrelor infusion is discontinued 10 minutes prior to heparin reversal with protamine. Ten urgent/emergent cardiovascular surgeries were performed at our institution using cangrelor with heparin for anticoagulation during CPB, and the majority were pulmonary thromboendarterectomy (60%). HIT was confirmed in 3 cases and was suspected in 4 which was found to be negative after the operation. One case of subacute B HIT and 2 cases of remote HIT were included in this series. This novel alternative intraoperative anticoagulation strategy was well tolerated by all patients. There was neither serious postoperative thrombotic event nor major postoperative bleeding complication that required reoperation. One death occurred in a patient with advanced intracardiac malignancy, whose life support was ultimately withdrawn postoperatively. Median postoperative intensive care unit stay was 7.2 ± 5.5 days, while median postoperative hospital stay was 16.3 ± 10.8 days. In patients with various phases of HIT who require urgent/emergent on-pump cardiovascular surgery, the use of cangrelor with heparin may be a convenient, safe, and effective alternative intraoperative anticoagulation strategy providing acceptable outcomes.

Successful Use of Cangrelor and Heparin for Cardiopulmonary Bypass in a Patient With Heparin-Induced Thrombocytopenia and End-Stage Renal Disease: A Case Report.

Heparin is the only well-established anticoagulant medication for cardiopulmonary bypass making selecting an alternative anticoagulant challenging in patients with heparin-induced thrombocytopenia. Other anticoagulant medications can cause significant postoperative bleeding, especially in patients with end-stage renal disease. We present a case of a 63-year-old woman requiring aortic valve replacement with a history of heparin-induced thrombocytopenia and end-stage renal disease. Cangrelor and heparin were successfully used during cardiopulmonary bypass, offering an option for anticoagulation management for a uniquely challenging patient population.

Anesthetic management of the patient undergoing heart transplantation.

Cardiac transplantation is the treatment of choice for patients with end-stage heart failure. Over the years, significant advances in patient selection, donor optimization and selection, and optimization of immunosuppression strategies have markedly improved outcomes. In this review, we highlight patient selection, donor management and procurement, heart transplantation procedure, and intraoperative and postoperative management of heart transplants.

Efficacy of a Low-Tidal Volume Ventilation Strategy to Prevent Reperfusion Lung Injury after Pulmonary Thromboendarterectomy.

RATIONALE: Reperfusion lung injury is a postoperative complication of pulmonary thromboendarterectomy that can significantly affect morbidity and mortality. Studies in other postoperative patient populations have demonstrated a reduction in acute lung injury with the use of a low-tidal volume (Vt) ventilation strategy. Whether this approach benefits patients undergoing thromboendarterectomy is unknown. OBJECTIVES: We sought to determine if low-Vt ventilation reduces reperfusion lung injury in patients with chronic thromboembolic pulmonary hypertension undergoing thromboendarterectomy. METHODS: Patients undergoing thromboendarterectomy at one center were randomized to receive either low (6 ml/kg predicted body weight) or usual care Vts (10 ml/kg) from the initiation of mechanical ventilation in the operating room through Postoperative Day 3. The primary endpoint was the onset of reperfusion lung injury. Secondary outcomes included severity of hypoxemia, days on mechanical ventilation, and intensive care unit and hospital lengths of stay. MEASUREMENTS AND MAIN RESULTS: A total of 128 patients were enrolled and included in the analysis; 63 were randomized to the low-Vt group and 65 were randomized to the usual care group. There was no statistically significant difference in the incidence of reperfusion lung injury between groups (32%, n=20 in the low-Vt group vs. 23%, n=15 in the usual care group; P=0.367). Although differences were noted in plateau pressures (17.9 cm H2O vs. 20.1 cm H2O, P<0.001) and peak inspiratory pressures (20.4 cm H2O vs. 23.0 cm H2O, P<0.001) between the low-Vt and usual care groups, respectively, mean airway pressures, PaO2/FiO2, days on mechanical ventilation, and ICU and hospital lengths of stay were all similar between groups. CONCLUSIONS: In patients with chronic thromboembolic pulmonary hypertension undergoing pulmonary thromboendarterectomy, intra- and postoperative ventilation using low Vts (6 mg/kg) compared with usual care Vts (10 mg/kg) does not reduce the incidence of reperfusion lung injury or improve clinical outcomes. Clinical trial registered with www.clinicaltrials.gov (NCT00747045).

Pulmonary endarterectomy: Part II. Operation, anesthetic management, and postoperative care.

Chronic thromboembolic pulmonary hypertension (CTEPH) results from recurrent or incomplete resolution of pulmonary embolism. CTEPH is much more common than generally appreciated. Although pulmonary embolism (PE) affects a large number of Americans, chronic pulmonary thromboembolic hypertension remains underdiagnosed. It is imperative that all patients with pulmonary hypertension (PH) be screened for the presence of CTEPH since this form of PH is potentially curable with pulmonary endarterectomy (PEA) surgery. The success of this procedure depends greatly on the collaboration of a multidisciplinary team approach that includes pulmonary medicine, cardiothoracic surgery, and cardiac anesthesiology. This review, based on the experience of more than 3000 pulmonary endarterectomy surgeries, is divided into 2 parts. Part I focuses on the clinical history and pathophysiology, diagnostic workup, and intraoperative echocardiography. Part II focuses on the surgical approach, anesthetic management, postoperative care, and complications.

Pulmonary endarterectomy: part I. Pathophysiology, clinical manifestations, and diagnostic evaluation of chronic thromboembolic pulmonary hypertension.

Chronic thromboembolic pulmonary hypertension (CTEPH) results from recurrent or incomplete resolution of pulmonary embolism. CTEPH is much more common than generally appreciated. Although pulmonary embolism (PE) affects a large number of Americans, chronic pulmonary hypertension (PH) remains underdiagnosed. It is imperative that all patients with PH be screened for the presence of CTEPH since this form of PH is potentially curable with pulmonary thromboendarterectomy (PTE) surgery. The success of this procedure depends greatly on the collaboration of a multidisciplinary team approach that includes pulmonary medicine, cardiothoracic surgery, and cardiac anesthesiology. This review, based on the experience of more than 3000 pulmonary endarterectomy surgeries, is divided into 2 parts. Part I focuses on the clinical history and pathophysiology, diagnostic workup, and intraoperative echocardiography. Part II focuses on the surgical approach, anesthetic management, postoperative care, and complications.