Short-term heart and lung support: extracorporeal membrane oxygenation and extracorporeal life support

Cytokine Adsorption in Critically Ill Patients Requiring ECMO Support

Systemic inflammation is a key characteristic of sepsis but also also in non-infectious conditions such as post-cardiac arrest syndrome. Cytokine adsorption and extracorporeal membrane oxygenation are emerging therapies applied in these critically ill patients, but the experience with their concurrent use is limited. We evaluated cytokine adsorption in critically ill patients requiring support with either veno-venous (vv) or veno-arterial (va) extracorporeal membrane oxygenation (ECMO) support and hypothesized that adsorber incorporation into the ECMO circuit was technically feasible and not associated with imminent risk. We analyzed data from the first six cases of a prospective single-center registry of patients undergoing veno-venous (vv) or veno-arterial (va) ECMO therapy. While in most published cases cytokine adsorbers were inserted into a hemofiltration circuit, we directly incorporated the adsorber into the ECMO circuit without interruption of continuous ECMO support. We observed no relevant side effects attributable to cytokine adsorption. Thirty-day mortality was 83% (predicted mortality 87%), indicating that the decision for adding cytokine adsorption may have been considered as an ultima ratio decision in severe cases with poor prognosis. Vasopressor or inotrope use, lactate level, and fluid balance did not change significantly when comparing pre- vs. post-cytokine adsorption values. Interestingly, the real-time course of the mentioned three surrogate parameters remained unaltered in all but two cases, regardless of cytokine removal. Beneficial effects of cytokine adsorption are plausible in two va-ECMO-treated patient, where increasing lactate began to drop after initiation of cytokine adsorption. Taken together, these data suggest that incorporation of cytokine adsorption into the management of critically ill patients requiring continued ECMO support is feasible and easy to handle. Whether cytokine removal improves clinical outcome in ECMO-treated patients should now be investigated in randomized controlled trials.

When all else fails: extracorporeal life support in therapy-refractory cardiogenic shock

OBJECTIVES

No guidelines for mechanical circulatory support in patients with therapy-refractory cardiogenic shock and multiorgan failure including ongoing cardiopulmonary resuscitation (CPR) exist. To achieve immediate cardiopulmonary stabilization, we established an interdisciplinary concept with on-site percutaneous extracorporeal life support (ECLS) implantation.

METHODS

From February 2012 to November 2014, 96 patients were deemed eligible for ECLS implantation. Establishing ECLS was successful in 87 patients (mean age 54 ± 13 years, 16% female, initial flow 4.4 ± 0.9 l/min). Aetiologies included acute coronary syndromes (n = 52, 60%), cardiomyopathies (n = 25, 29%) and other pathologies. Fifty-nine patients (68%) had been resuscitated, and in 27 (31%), implantation was performed during CPR; 11 patients (13%) were awake at implantation and 20 (23%) underwent implantation in the referring hospital.

RESULTS

Metabolic parameters differed in non-survivors versus survivors before ECLS implantation (pH 7.15 ± 0.23 vs. 7.27 ± 0.18, P = 0.007; lactate levels 10.90 ± 6.00 mmol/l vs. 8.79 ± 5.78 mmol/l, P = 0.091) and 6 h postimplantation (pH 7.27 ± 0.11 vs. 7.37 ± 0.11, P < 0.001; lactate levels 10.19 ± 5.52 mmol/l vs. 5.52 ± 4.17 mmol/l, P < 0.001). Altogether 44 patients could be weaned, and 9 were bridged to assist device implantation and 1 to heart transplantation. The mean time of support was 6 days, and the 30-day survival rate was 47% (n = 41).

CONCLUSIONS

ECLS serves as a bridge-to-decision and bridge-to-treatment device. Our interdisciplinary ECLS programme achieved acceptable survival of critically ill patients despite a substantial percentage of patients having been resuscitated and no absolute exclusion criteria. Further studies defining inclusion- and exclusion criteria might additionally improve outcome.

Bicaval dual-lumen cannula for venovenous extracorporeal membrane oxygenation: Avalon© cannula in childhood disease

Severe acute refractory respiratory failure is considered a life-threatening situation, with a high mortality of 40 to 60%. When conservative oxygenation methods fail, a lifesaving measure is the introduction of extracorporeal membrane oxygenation (ECMO). Venovenous ECMO (VV-ECMO) is a preferred modality of support for patients with refractory acute respiratory failure. Specifically, bicaval VV-ECMO is a well-recognized and validated therapy, where single or double periphery venous access is used for the insertion of two differently sized cannulas in order to achieve adequate blood oxygenation. Compared to venoarterial ECMO, in VV-ECMO, the rate of complications, such as thrombosis, bleeding, infection and ischemic events, is lower. On the other hand, the size and insertion location is an obstacle to patient mobilization. This is a considerable problem for patients where the time interval for lung recovery and the bridge to the transplantation is prolonged. To address this issue, a dual-lumen, single venovenous cannula was introduced. Here, by insertion of one single catheter in one target vessel, in a majority of cases in the right internal jugular vein, satisfactory oxygenation of the patient is achieved. In this form, the instituted VV-ECMO enables patient mobility, better physical rehabilitation and facilitates pulmonary extubation and toilet.

However, relatively early, after the first short-term reports were published, a relatively high complication rate became evident. In the recent literature, the complication rate using actual commercially available double-lumen venovenous cannula ranges between 5 and 30%. These cases were mostly conjoined to the implantation phase or the early postoperative phase and vary between right heart perforation to migration of the cannula.

This review focuses on complications allied to commercially available dual-lumen, single, venovenous cannula implantation, pointing out the critical segments of the implantation process and analyzing the structure of the device.