Esmolol Corrects Severe Hypoxemia in Patients with Femoro-Femoral Venoarterial Extracorporeal Life Support for Lung Transplantation.

Competitive flows syndrome result in severe regional hypoxemia when the deoxygenated flow from the native left ventricle (LV) competes with oxygenated flow from extracorporeal life support (ECLS) pump with potentially severe consequences for the cerebral and coronary circulations. Fast correction of hypoxemia could be obtained by decreasing native LV flow by infusion of a short-acting beta-blocker (esmolol). Our purpose was to retrospectively review the efficacy of esmolol in this situation and hypothesize on the potential mechanisms of action and the associated risks. This is a retrospective analysis of five clinical cases, who underwent lung transplantation and a femoro-femoral venoarterial (VA) ECLS. The patients presented severe hypoxemia (SpO2 < 85%) measured through photoplethysmography on a right hand finger. From the patients' medical records and anesthesia flowcharts, hemodynamic, right heart catheterization, echocardiography variables, and arterial blood gas results were noted before and after injection of esmolol. Mechanical ventilation and VA ECLS function variables were optimized and unchanged before and after esmolol injection. All patients had terminal respiratory failure with pulmonary hypertension and conserved LV systolic function. Immediately following esmolol injection (1.3 ± .7 mg/kg; mean ± 1 SD), SpO2 increased from 73% ± 12 to 95% ± 6; blood to arterial partial pressure in CO2 (PaCO2) decreased from 52 ± 18 to 35 ± 7 mmHg systolic pulmonary artery pressure decreased from 61 ± 8 to 50 ± 12 mmHg; the pulmonary artery oxygen saturation (SvO2); increased from 51% ± 24 to 77% ± 12; systemic arterial pressure or catecholamine requirements were unchanged. In conclusion, these results suggest that injection of esmolol allowed rapid correction of regional hypoxemia occurring during lung transplantation despite femoro-femoral VA ECLS. The mechanism is probably a decreased cardiac output of the native LV due to esmolol-induced negative inotropic and chronotropic effects without significant adverse effects on systemic tissue perfusion.

Can mortality due to circulatory failure in comatose out-of-hospital cardiac arrest patients be predicted on admission? A study in a retrospective derivation cohort validated in a prospective cohort.

PURPOSE: Circulatory failure (CF) influences management of out-of-hospital cardiac arrest (OHCA) patients and the decision of circulatory assistance. We performed a study to identify on hospital admission patients at risk for CF-related death. MATERIALS AND METHODS: This is a single-center study including OHCA patients without obvious extracardiac cause and sustained return of spontaneous circulation, in a retrospective derivation (RC) and prospective validation cohort (PC). Univariate/multivariate logistic regression was used in the RC to determine a score predicting CF-related death (due to rearrest or persistent shock despite adequate fluid and catecholamine treatment). The score was validated in the PC. RESULTS: We included 207 patients in the RC and 96 in the PC. Circulatory failure occurred in 59% of RC and 63% of PC patients (P = .70); 35% in both cohorts died of CF. In multivariate regression, correlates of CF-related death making up the logistic score were arterial pH (P < .0001) and shock requiring catecholamines on admission (P = .0045). In the PC, for a logistic score cut-off of 0.5, sensitivity for CF-related death was 50%; specificity, 92%. Patients with shock and arterial pH less than or equal to 7.11 had a CF-related death probability greater than 0.5. CONCLUSION: A logistic score based on arterial pH and shock requiring catecholamines on admission can predict CF-related death in OHCA patients.

Influence of α-stat and pH-stat blood gas management strategies on cerebral blood flow and oxygenation in patients treated with therapeutic hypothermia after out-of-hospital cardiac arrest: a crossover study.

OBJECTIVES: In patients treated with therapeutic hypothermia after out-of-hospital cardiac arrest, two blood gas management strategies are used regarding the PaCO2 target: α-stat or pH-stat. We aimed to compare the effects of these strategies on cerebral blood flow and oxygenation. DESIGN: Prospective observational single-center crossover study. SETTING: ICU of University hospital. PATIENTS: Twenty-one therapeutic hypothermia-treated patients after out-of-hospital cardiac arrest more than 18 years old without history of cerebrovascular disease were included. INTERVENTIONS: Cerebral perfusion and oxygenation variables were compared in α-stat (PaCO2 measured at 37 °C) versus pH-stat (PaCO2 measured at 32-34 °C), both strategies maintaining physiological PaCO2 values: 4.8-5.6 kPa (36-42 torr). MEASUREMENTS AND MAIN RESULTS: Bilateral transcranial middle cerebral artery flow velocities using Doppler and jugular vein oxygen saturation were measured in both strategies 18 hours (14-23 hr) after the return of spontaneous circulation. Pulsatility and resistance indexes and cerebral oxygen extraction were calculated. Data are expressed as median (interquartile range 25-75) in α-stat versus pH-stat. No differences were found in temperature, arterial blood pressure, and oxygenation between α-stat and pH-stat. Significant differences were found in minute ventilation (p = 0.006), temperature-corrected PaCO2 (4.4 kPa [4.1-4.6 kPa] vs. 5.1 kPa [5.0-5.3 kPa], p = 0.0001), and temperature-uncorrected PaCO2 (p = 0.0001). No differences were found in cerebral blood velocities and pulsatility and resistance indexes in the overall population. Significant differences were found in jugular vein oxygen saturation (83.2% [79.2-87.6%] vs. 86.7% [83.2-88.2%], p = 0.009) and cerebral oxygen extraction (15% [11-20%] vs. 12% [10-16%], p = 0.01), respectively. In survivors, diastolic blood velocities were 25 cm/s (19-30 cm/s) versus 29 cm/s (23-35 cm/s) (p = 0.004), pulsatility index was 1.10 (0.97-1.18) versus 0.94 (0.89-1.05) (p = 0.027), jugular vein oxygen saturation was 79.2 (71.1-81.8) versus 83.3% (76.6-87.8) (p = 0.033), respectively. However, similar results were not found in nonsurvivors. CONCLUSIONS: In therapeutic hypothermia-treated patients after out-of-hospital cardiac arrest at physiological PaCO2, α-stat strategy increases jugular vein blood desaturation and cerebral oxygen extraction compared with pH-stat strategy and decreases cerebral blood flow velocities in survivors.

Emergency transseptal transcatheter mitral valve-in-valve implantation.

AIMS: We report a case of emergency transcatheter heart valve implantation in a failing mitral bioprosthesis via a transseptal access complicated by the atrial migration of a prosthesis. METHODS AND RESULTS: A 42-year-old woman was referred for stenotic failure of a mitral bioprosthesis. A transapical valve-in-valve implantation was initially planned. However, due to sudden haemodynamic deterioration, an emergency transseptal implantation via a femoral venous access was undertaken. Following cardiac arrest, the procedure was performed with extracorporeal membrane oxygenation (ECMO), and was complicated by the migration of a valve, which was left moving freely in the left atrium. A second valve was successfully implanted in the mitral bioprosthesis. Following initial clinical recovery, there was a sudden recurrence of heart failure due to entrapment of the migrated valve in the implanted valve in a "reverse position", which was dislodged percutaneously in an emergency procedure. The valve later migrated into the left atrial appendage. Immediate outcome was uneventful, but the patient suddenly died six months later. CONCLUSIONS: Transseptal transcatheter mitral valve-in-valve implantation is feasible, even in an emergency setting with ECMO. Valve migration in the left atrium may occur and lead to late entrapment in a "reverse position", with significant haemodynamic consequences.

Role of cardiac troponin in the diagnosis of acute myocardial infarction in comatose patients resuscitated from out-of-hospital cardiac arrest.

BACKGROUND: Troponin is a major diagnostic criterion of acute myocardial infarction (AMI) but in out-of-hospital cardiac arrest (OHCA) patients, its diagnostic value may be altered by cardiopulmonary resuscitation. METHODS: Single-centre study assessing the diagnostic characteristics of troponin for AMI diagnosis in consecutive patients resuscitated from OHCA between 2002 and 2008 with coronary angiogram (CA) performed on admission. Patients with obvious non-cardiac cause of OHCA, unsustained or absent return of spontaneous circulation were excluded. AMI was defined on CA by the presence of acute occlusion or critical stenosis with intracoronary fresh thrombus easily crossed by an angioplasty wire. Troponin concentration was recorded once on admission and once 6-12h after the OHCA. RESULTS: A total of 163 patients aged 56 (median) years (interquartile range (IQR) 48-65) was included, all comatose. Most prevalent initial OHCA rhythms were ventricular fibrillation (49%) and asystole (41%). AMI was diagnosed on coronary angiogram in 37% of the patients. Median troponin concentration on admission was 1.7 (0.3-10)ngml(-1) and sensitivity for AMI diagnosis was 72% and specificity 75% for a 2.5ngml(-1) cut-off. A combined criterion comprising ST elevation and troponin >2.5ngml(-1) had a sensitivity of 93% and specificity of 64%. Six to twelve hours after the OHCA, median troponin concentration was 7.6ngml(-1) (1.4-47.5), sensitivity was 84% and specificity 84% for a 14.5ngml(-1) cut-off. CONCLUSION: Troponin I has a good diagnostic value for AMI diagnosis in OHCA patients. In combination with ST elevation, troponin I on admission achieves a very high sensitivity.

Value of post-resuscitation electrocardiogram in the diagnosis of acute myocardial infarction in out-of-hospital cardiac arrest patients.

BACKGROUND: Diagnosis of acute myocardial infarction (AMI) in out-of-hospital cardiac arrest (OHCA) patients is important because immediate coronary angiography with coronary angioplasty could improve outcome in this setting. However, the value of acute post-resuscitation electrocardiographic (ECG) data for the detection of AMI is debatable. METHODS: We assessed the diagnostic characteristics of post-resuscitation ECG changes in a retrospective single centre study evaluating several ECG criteria of selection of patients undergoing AMI, in order to improve sensitivity, even at the expense of specificity. Immediate post resuscitation coronary angiogram was performed in all patients. AMI was defined angiographically using coronary flow and plaque morphology criteria. RESULTS: We included 165 consecutive patients aged 56 (IQR 48-67) with sustained return of spontaneous circulation after OHCA between 2002 and 2008. 84 patients had shockable, 73 non-shockable and 8 unknown initial rhythm; 36% of the patients had an AMI. ST-segment elevation predicted AMI with 88% sensitivity and 84% specificity. The criterion including ST-segment elevation and/or depression had 95% sensitivity and 62% specificity. The combined criterion including ST-segment elevation and/or depression, and/or non-specific wide QRS complex and/or left bundle branch block provided a sensitivity and negative predictive value of 100%, a specificity of 46% and a positive predictive value of 52%. CONCLUSION: In patients with OHCA without obvious non-cardiac causes, selection for coronary angiogram based on the combined criterion would detect all AMI and avoid the performance of the procedure in 30% of the patients, in whom coronary angiogram did not have a therapeutic role.