Capillary refill time assessment after fluid challenge in patients on venoarterial extracorporeal membrane oxygenation: A retrospective study.

BACKGROUND: Monitoring fluid therapy is challenging in patients assisted with Veno-arterial ECMO. The aim of our study was to evaluate the usefulness of capillary refill time to assess the response to fluid challenge in patients assisted with VA-ECMO. METHODS: Retrospective monocentric study in a cardiac surgery ICU. We assess fluid responsiveness after a fluid challenge in patients on VA-ECMO. We recorded capillary refill time before and after fluid challenge and the evolution of global hemodynamic parameters. RESULTS: A total of 27 patients were included. The main indications for VA-ECMO were post-cardiotomy cardiogenic shock (44%). Thirteen patients (42%) were responders and 14 non-responders (58%). In the responder group, the index CRT decreased significantly (1.7 [1.5; 2.1] vs. 1.2 [1; 1.3] s; p = 0.01), whereas it remained stable in the non-responder group (1.4 [1.1; 2.5] vs. 1.6 [0.9; 1.9] s; p = 0.22). Diagnosis performance of CRT variation to assess response after fluid challenge shows an AUC of 0.68 (p = 0.10) with a sensitivity of 79% [95% CI, 52-92] and a specificity of 69% [95% CI, 42-87], with a threshold at 23%. CONCLUSION: In patients treated with VA-ECMO index capillary refill time is a reliable tool to assesses fluid responsiveness. SPECIALTY: Critical care, Cardiac surgery, ECMO.

Levosimendan in patients undergoing extracorporeal membrane oxygenation after cardiac surgery: an emulated target trial using observational data.

BACKGROUND: Retrospective cohorts have suggested that levosimendan may facilitate the weaning of veno-arterial extracorporeal membrane oxygenation (VA-ECMO). We therefore studied this clinical question by emulating a randomized trial with observational data. METHODS: All patients with refractory postcardiotomy cardiogenic shock and assisted with VA-ECMO, admitted to a surgical intensive care unit at La Pitié-Salpêtrière Hospital between 2016 and 2019, were eligible. To avoid immortal-time bias, we emulated a target trial sequentially comparing levosimendan administration versus no levosimendan administration in patients treated with VA-ECMO. The primary outcome was time to successful ECMO weaning. The secondary outcomes were 30-day and 1-year mortality. We performed a multivariable analysis to adjust for confounding at baseline. RESULTS: Two hundred and thirty-nine patients were included in the study allowing building a nested trials cohort of 1434 copies of patients. No association of levosimendan treatment and VA-ECMO weaning was found (HR = 0.91, [0.57; 1.45], p = 0.659 in multivariable analysis), or 30-day mortality (OR = 1.03, [0.52; 2.03], p = 0.940) and 1-year mortality (OR = 1.00, [0.53; 1.89], p = 0.999). CONCLUSIONS: Using the emulated target trial framework, this study did not find any association of levosimendan treatment and ECMO weaning success after postcardiotomy cardiogenic shock. However, the population of interest remains heterogeneous and subgroups might benefit from levosimendan.

A new machine learning algorithm to predict veno-arterial ECMO implantation after post-cardiotomy low cardiac output syndrome.

BACKGROUND: Post-cardiotomy low cardiac output syndrome (PC-LCOS) is a life-threatening complication after cardiac surgery involving a cardiopulmonary bypass (CPB). Mechanical circulatory support with veno-arterial membrane oxygenation (VA-ECMO) may be necessary in the case of refractory shock. The objective of the study was to develop a machine-learning algorithm to predict the need for VA-ECMO implantation in patients with PC-LCOS. PATIENTS AND METHODS: Patients were included in the study with moderate to severe PC-LCOS (defined by a vasoactive inotropic score (VIS) > 10 with clinical or biological markers of impaired organ perfusion or need for mechanical circulatory support after cardiac surgery) from two university hospitals in Paris, France. The Deep Super Learner, an ensemble machine learning algorithm, was trained to predict VA-ECMO implantation using features readily available at the end of a CPB. Feature importance was estimated using Shapley values. RESULTS: Between January 2016 and December 2019, 285 patients were included in the development dataset and 190 patients in the external validation dataset. The primary outcome, the need for VA-ECMO implantation, occurred respectively, in 16% (n = 46) and 10% (n = 19) in the development and the external validation datasets. The Deep Super Learner algorithm achieved a 0.863 (0.793-0.928) ROC AUC to predict the primary outcome in the external validation dataset. The most important features were the first postoperative arterial lactate value, intraoperative VIS, the absence of angiotensin-converting enzyme treatment, body mass index, and EuroSCORE II. CONCLUSIONS: We developed an explainable ensemble machine learning algorithm that could help clinicians predict the risk of deterioration and the need for VA-ECMO implantation in moderate to severe PC-LCOS patients.

Development and Validation of a Predictive Score for Prolonged Mechanical Ventilation After Cardiac Surgery.

OBJECTIVES: The authors aimed to identify risk factors associated with prolonged mechanical ventilation (PMV) after scheduled cardiac surgery under cardiopulmonary bypass (CPB). DESIGN: A single-center, observational study. SETTING: Tertiary hospital. PARTICIPANTS: All adult patients who underwent scheduled cardiac surgery under cardiopulmonary bypass between January 2017 and December 2017. INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: Among the 568 patients included, 68 (12.0%) presented a PMV. The median ventilation time was 5.7 hours in the group without PMV and 85.2 hours in the group with PMV. A logistic regression found five variables independently associated with the occurrence of PMV: (1) prior cardiac surgery, (2) preoperative congestive heart failure, (3) preoperative creatinine clearance <30 mL/min/1.73 m², (4) intraoperative implantation of extracorporeal membrane oxygenation, and (5) serum lactate >4 mmol/L on admission. A predictive score to allow the authors to anticipate PMV was developed from the regression coefficient of perioperative factors independently associated with PMV. With a threshold of 2/13, the score had a sensitivity of 80.9%, a specificity of 80.5%, a positive predictive value of 37.2%, and a negative predictive value of 96.7%. The score then was validated in a distinct cohort. CONCLUSIONS: The study authors have developed a simple score to predict PMV in patients undergoing cardiac surgery with CPB. This score could allow clinicians to identify a high-risk population that might benefit from specific management upon arrival in the intensive care unit.

Weaning-Related Shock in Patients With ECMO: Incidence, Mortality, and Predisposing Factors.

OBJECTIVE: Venoarterial extracorporeal membrane oxygenation (VA-ECMO) commonly is used to manage refractory cardiogenic shock after cardiac surgery, with 31% to 76% of patients successfully weaned off their ECMO. However, it is associated with high mortality rates, and 20% to 65% of weaned patients do not survive to hospital discharge. This study aimed to assess the incidence of ECMO weaning-related shock, the risk factors, and prognosis in the intensive care unit (ICU). DESIGN: Retrospective observational cohort study. SETTING: Surgical ICU of Cardiology Institute of Pitié-Salpêtrière University Hospital (Paris-France). PARTICIPANTS: Patients who were assisted with a peripheral VA-ECMO from January 2015 to December 2017 were included. Patients with venovenous, central, or right ECMO were excluded. MEASUREMENTS: The authors collected data on patients' characteristics, during and after surgery. The indications for VA-ECMO implantation were ventricular dysfunction, primary graft dysfunction, and refractory cardiac arrest. Weaning-related shock was defined as the need to introduce or increase the dose of catecholamine at ECMO explantation or in the following week. RESULTS: After weaning off VA-ECMO, 56 of 146 patients (38.4%) presented weaning-related shock: 55% were septic shocks, 12.5 % were caused by right ventricle failure, and 7.1% by hemorrhage. ICU mortality was 42% versus 8% in patients who did not present shock. Multivariate analysis showed that patients with pulmonary hypertension and those with norepinephrine before weaning were more likely to develop shock. CONCLUSION: ECMO weaning-related shock is frequent in patients with refractory cardiogenic shock after cardiac surgery. This is most commonly caused by sepsis and causes higher mortality rates, calling for further evaluation.

Risk Factors for Developing Severe Acute Kidney Injury in Adult Patients With Refractory Postcardiotomy Cardiogenic Shock Receiving Venoarterial Extracorporeal Membrane Oxygenation.

OBJECTIVES: Postcardiotomy cardiogenic shock occurs in 2-6% of patients undergoing cardiac surgery, and 1% of cardiac surgery patients will require mechanical circulatory support using venoarterial extracorporeal membrane oxygenation. Acute kidney injury is a frequent complication in this population and negatively impacts the survival. We aimed to determine whether the timing of extracorporeal membrane oxygenation implantation influences the renal prognosis of these patients. DESIGN: Retrospective observational cohort study between January 2013 and December 2016. SETTING: An 18-bed surgical ICU in a university hospital. PATIENTS: A total of 4,796 consecutive adult patients who underwent cardiac surgery were included in the study, and 347 (7.2%) were assisted with venoarterial extracorporeal membrane oxygenation for refractory postcardiotomy cardiogenic shock. The patients who died during the first 48 hours after venoarterial extracorporeal membrane oxygenation implantation were excluded. The complete-case analysis included 257 patients. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The primary outcome was the occurrence, within 10 days following the venoarterial extracorporeal membrane oxygenation implantation, of a stage 3 acute kidney injury defined by the Kidney Disease: Improving Global Outcomes group. One hundred sixty-nine patients (65.7%) presented with a Kidney Disease: Improving Global Outcomes stage 3 acute kidney injury; 14 patients (5.4%) died before the end of the follow-up period, without developing the primary outcome. Ninety-two percent of patients with Kidney Disease: Improving Global Outcomes 3 acute kidney injury received renal replacement therapy, for a median duration of 7 days (3-16 d). Late implantation of venoarterial extracorporeal membrane oxygenation was independently associated with an increased risk of Kidney Disease: Improving Global Outcomes stage 3 acute kidney injury (odds ratio, 2.81 [95% CI, 1.31-6.07]; p = 0.008). The other factors associated with Kidney Disease: Improving Global Outcomes stage 3 acute kidney injury were preoperative left ventricular ejection fraction (odds ratio, 1.03 [95% CI, 1.01-1.05]; p = 0.007), intraoperative plasma transfusion (odds ratio, 1.13 [95% CI, 1.02-1.26]; p = 0.022), increased bilirubinemia level (odds ratio, 1.013 [95% CI, 1.001-1.026]; p = 0.032), and increased creatinine levels (odds ratio, 1.012 [95% CI, 1.006-1.018]; p < 0.001) on the day of implantation. CONCLUSIONS: Significant kidney dysfunction is particularly frequent in patients with refractory postcardiotomy cardiogenic shock assisted with venoarterial extracorporeal membrane oxygenation. Early implantation of extracorporeal membrane oxygenation may help prevent acute kidney injury.

Colour Doppler ultrasound after major cardiac surgery improves diagnostic accuracy of the pulmonary infection score in acute respiratory failure: A prospective observational study.

BACKGROUND: Postoperative pneumonia is a frequent complication after cardiac surgery, and its diagnosis is difficult. Little is known about the diagnostic accuracy of lung ultrasound (LUS) in the detection of pneumonia in cardiac surgical patients. The substitution of chest radiography by colour Doppler LUS (LUS-sCPIS) in the simplified clinical pulmonary infection score (sCPIS) could improve the diagnosis of pneumonia following cardiac surgery. OBJECTIVE: The aim of this study was to compare the diagnostic accuracy of LUS-sCPIS and of sCPIS alone in the detection of postoperative pneumonia after cardiac surgery. DESIGN: A prospective study of diagnostic accuracy. SETTING: A Surgical Intensive Care Unit of a French University Hospital. PATIENTS: Fifty-one patients with acute respiratory failure within 72 h after cardiac surgery were enrolled between January and May 2015. MAIN OUTCOME MEASURE: The two index tests, LUS-sCPIS and sCPIS, were calculated for all patients at the onset of acute respiratory failure. The reference standard for the diagnosis of pneumonia was based on the consensus of three physicians, blind to the sCPIS and LUS-sCPIS data, based on a posthoc review of all the clinical, radiological and microbiological evidence. The diagnostic accuracy of LUS-sCPIS was compared with that of sCPIS in the detection of postoperative pneumonia. RESULTS: Pneumonia was diagnosed in 26 out of 51 patients. The LUS-sCPIS detected the presence of pneumonia with a sensitivity of 92% (95% CI 0.85 to 0.99) and a specificity of 68% (95% CI 0.55 to 0.81). The sCPIS detected the presence of pneumonia with a sensitivity of 35% (95% CI 0.22 to 0.48) and a specificity of 84% (95% CI 0.74 to 0.94). The area under the curve (AUC) of LUS-sCPIS at 0.80 (95% CI 0.69 to 0.91) was higher than the AUC of sCPIS at 0.59 (95% CI 0.47 to 0.71; P = 0.0008). CONCLUSION: Compared with sCPIS, LUS-sCPIS improved diagnostic accuracy in the detection of postoperative pneumonia in patients with acute respiratory failure after cardiac surgery. It could be a useful bedside tool to guide pneumonia management. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT03279887.

The effect of local anesthetic continuous wound infusion for the prevention of postoperative pneumonia after on-pump cardiac surgery with sternotomy: the STERNOCAT randomized clinical trial.

PURPOSE: Postoperative pain after cardiac surgery, exacerbated by cough and sternal mobilization, limits clearance of bronchopulmonary secretions and may predispose to postoperative pneumonia. In this study, we tested the ability of local anesthetic continuous wound infusion to prevent pneumonia after cardiac surgery with sternotomy and cardiopulmonary bypass (CPB) owing to better analgesia and bronchopulmonary drainage. METHODS: In this randomized, double-blind, placebo-controlled trial conducted in five academic centers, patients undergoing cardiac surgery with sternotomy and CPB were enrolled from February 2012 until November 2014, and were followed over 30 days. Patients were assigned to a 48-h infusion (10 ml h-1) of L-bupivacaine (12.5 mg h-1) or placebo (saline) via a pre-sternal multiperforated catheter. Anesthesia and analgesia protocols were standardized. The primary end point was the incidence of pneumonia during the study period, i.e., until hospital discharge or 30 days. We hypothesized a 30% reduction in the incidence of pneumonia. RESULTS: Among 1493 randomized patients, 1439 completed the trial. Pneumonia occurred in 36/746 patients (4.9%) in the L-bupivacaine group and in 42/739 patients (5.7%) in the placebo group (absolute risk difference taking into account center and baseline risk of postoperative pneumonia, - 1.3% [95% CI - 3.4; 0.8] P = 0.22). In the predefined subgroup of patients at high risk, L-bupivacaine decreased the incidence of pneumonia (absolute risk difference, - 5.6% [95% CI - 10.0; - 1.1], P = 0.01). CONCLUSIONS: After cardiac surgery with sternotomy, continuous wound infusion of L-bupivacaine failed to decrease the incidence of pneumonia. These findings do not support the use of local anesthetic continuous wound infusion in this indication. Further study should investigate its effect in high-risk patients. TRIAL REGISTRATION: EudraCT Number: 2011-003292-10; Clinicaltrials.gov Identifier: NCT01648777.

Monitoring of left ventricular assist device implantation and set-up with miniaturized transoesophageal echocardiography: Initial experience at La Pitié-Salpêtrière Hospital and possible application fields.

BACKGROUND: Left ventricular assist devices are valuable options for mechanical circulatory support in patients with severe heart failure as a bridge to cardiac transplantation, to recovery, or as destination therapy. Transoesophageal echocardiography plays a key role in the management of left ventricular assist device patients; either in guiding the device implantation or in post-operative haemodynamic assessment. The aim of this observational study is to investigate the usefulness of a miniaturized transoesophageal echocardiography probe designed for continuous haemodynamic monitoring (haemodynamic transoesophageal echocardiography; ImaCor, Garden City, NY) in the haemodynamic assessment of patients undergoing left ventricular assist device implantation. METHODS: Between June 2014 and September 2014, seven consecutive patients underwent left ventricular assist device implantation for severe heart failure. A haemodynamic transoesophageal echocardiography probe was used for continuous haemodynamic monitoring in the pre-, intra- and post-operative periods. All procedures were performed by haemodynamic transoesophageal echocardiography-trained physicians. RESULTS: All data were recorded and used without need of a further haemodynamic device. The average number of haemodynamic assessments in each patient was 5.3. The average number of haemodynamic assessments leading to therapeutic changes in each patient was 2.6. The mean duration of haemodynamic transoesophageal echocardiography probe insertion was approximately 20 hours (9 hours - 72 hours). No device complications were noticed during this period. CONCLUSIONS: This observation suggests that haemodynamic monitoring using the haemodynamic transoesophageal echocardiography system in left ventricular assist device patients is feasible after a brief training period. The overall impact of haemodynamic transoesophageal echocardiography use in these patients is yet to be determined and further studies are still required.