Extracorporeal membrane oxygenation in adults: experience from the Middle East

Weaning from veno-venous extracorporeal membrane oxygenation: how I do it

Veno-venous extracorporeal membrane oxygenation (VV ECMO) is a rescue treatment for acute respiratory distress syndrome (ARDS) failing protective mechanical ventilation. It temporarily provides proper gas exchange: hypoxia is treated by adjusting the blood flow rate and fraction in spired oxygen over the ventilator (FiO2) on the extracorporeal membrane oxygenation (ECMO) circuit while CO2 removal is regulated by the ECMO fresh gas flow. Therefore, ventilator settings can be gradually reduced allowing the lungs to rest and recover. Nowadays, indications for ECMO referral and implantation are clearly formulated; on the contrary, little evidence currently exists to guide the process of weaning from ECMO support, especially concerning the timing during the course of lung healing. Therefore, indications to stop ECMO are less well standardized so that in clinical trials extracorporeal assistance is generally continued until lung recovery, with neither specific nor homogenous criteria for withdrawal. Notably, in almost all papers dealing with data on VV ECMO support, the management of weaning and the weaning procedure itself are not described. The aim of this paper is to make a picture of VV ECMO weaning, as it is performed in three European large volume intensive care units (ICUs) which represent referral centers for VV ECMO treatment. We focused on data concerning the timing of VV ECMO weaning and parameters at the time of weaning, in order to assess adequacy and safety of VV ECMO removal.

Extra-corporeal membrane oxygenation for refractory cardiogenic shock after adult cardiac surgery: a systematic review and meta-analysis

BACKGROUND

Postcardiotomy cardiogenic shock (PCCS) refractory to inotropic support and intra-aortic balloon pump (IABP) occurs rarely but is almost universally fatal without mechanical circulatory support. In this systematic review and meta-analysis we looked at the evidence behind the use of veno-arterial extra-corporeal membrane oxygenation (VA ECMO) in refractory PCCS from a patient survival rate and determinants of outcome viewpoint.

METHODS

A systematic review was performed in January 2017 using PubMed (with no defined time period) using the keywords "postcardiotomy", "cardiogenic shock", "extracorporeal membrane oxygenation" and "cardiac surgery". We excluded papers pertaining to ECMO following paediatric cardiac surgery, medical causes of cardiogenic shock, as well as case reports, review articles, expert opinions, and letters to the editor. Once the studies were collated, a meta-analysis was performed on the proportion of survivors in those papers that met the inclusion criteria. Meta-regression was performed for the most commonly reported adverse prognostic indicators (API).

RESULTS

We identified 24 studies and a cumulative pool of 1926 patients from 1992 to 2016. We tabulated the demographic data, including the strengths and weaknesses for each of the studies, outcomes of VA ECMO for refractory PCCS, complications, and APIs. All the studies were retrospective cohort studies. Meta-analysis of the moderately heterogeneous data (95% CI 0.29 to 0.34, p < 0.01, I 2  = 60%) revealed overall survival rate to hospital discharge of 30.8%. Some of the commonly reported APIs were advanced age (>70 years, 95% CI -0.057 to 0.001, P = 0.058), and long ECMO support (95% CI -0.068 to 0.166, P = 0.412). Postoperative renal failure, high EuroSCORE (>20%), diabetes mellitus, obesity, rising lactate whilst on ECMO, gastrointestinal complications had also been reported.

CONCLUSION

Haemodynamic support with VA ECMO provides a survival benefit with reasonable intermediate and long-term outcomes. Many studies had reported advanced age, renal failure and prolonged VA ECMO support as the most likely APIs for VA ECMO in PCCS. EuroSCORE can be utilized to anticipate the need for prophylactic perioperative VA ECMO in the high-risk category. APIs can be used to aid decision-making regarding both the institution and weaning of ECMO for refractory PCCS.

Survival, quality of life and impact of right heart failure in patients with acute cardiogenic shock treated with ECMO

BACKGROUND

Mechanical circulatory support is increasingly used in acute cardiogenic shock.

OBJECTIVE

To assess treatment strategies for cardiogenic shock.

METHODS

Data of 57 patients in acute intrinsic cardiogenic shock treated with ECMO were analyzed. Different subsequent strategies (weaning, VAD, transplantation) were followed.​

RESULTS

Overall 1, 2, and 4-year survival was 36.8 ± 6.4%, 32.2 ± 6.4%, 29.8 ± 6.3%. Elevated lactate and hemorrhagic complications (all p in patients with right heart failure prior to ECMO implantation, BVAD therapy showed a trend (p=0.058) towards superior survival compared with LVAD therapy. Seven of the BVAD patients received successful transplantation, with a 1-year survival of 71%. Among survivors Short Form 36 reported significantly lower combined physical scores (p=0.004).

CONCLUSIONS

Right heart assessment prior to ECMO implantation may be beneficial to provide tailored therapy if ECMO weaning fails. Survival after cardiogenic shock requiring ECMO seems to be associated with impaired long-term quality of life.

Extracorporeal cardiopulmonary resuscitation for adult patients who underwent post-cardiac surgery

Background

Refractory cardiac arrest (CA) occasionally develops in patients after cardiac surgery.

Objective

To examine the clinical outcomes of extracorporeal cardiopulmonary resuscitation (ECPR) in adult patients with post-cardiotomy CA.

Methods

This was a retrospective study of the 9-year experience (from January 2004 to May 2012) of the Beijing Anzhen Hospital with ECPR in adult patients with post-cardiotomy CA. At this hospital, a dedicated ECPR team is available 24/7 for emergency cases requiring ECPR. Demographic data, biochemical data, survival, morbidity, and complications were examined before, during, and after ECPR. Outcomes were compared between survivors and non-survivors.

Results

Twenty-four adult patients (19 men and 5 women; mean age: 59.3 ± 11.9 years) received ECPR support for post-cardiotomy CA. The cardiac surgery procedures included coronary artery bypass grafting (n = 20, 83.3 %), valvular surgery alone (n = 2, 8.3 %), and correction of congenital heart defects (n = 2, 8.3 %). The mean extracorporeal membrane oxygenation (ECMO) duration was 115.23 ± 70.17 h. Twenty-one patients received ECPR after intra-aortic balloon pump, and three patients received ECPR directly. The main cause of mortality was multiple system organ failure (n = 12, 50.0 %). Approximately one-half of non-survivors had severe neurologic impairments. Among 16 patients who were weaned off ECMO support, eight patients survived to hospital discharge.

Conclusions

ECPR can be effective for partial cardiopulmonary support to resuscitate adult patients suffering from refractory CA after cardiac surgery. Improvement in outcomes of patients who received ECPR requires a multidisciplinary approach to protect organ function and limit organ injury before and during cardiac support.