Augmented venous access in the problematic ECMO patient: a case report

Neutrophils: a key component in ECMO-related acute organ injury

Extracorporeal membrane oxygenation (ECMO), as an extracorporeal life support technique, can save the lives of reversible critically ill patients when conventional treatments fail. However, ECMO-related acute organ injury is a common complication that increases the risk of death in critically ill patients, including acute kidney injury, acute brain injury, acute lung injury, and so on. In ECMO supported patients, an increasing number of studies have shown that activation of the inflammatory response plays an important role in the development of acute organ injury. Cross-cascade activation of the complement system, the contact system, and the coagulation system, as well as the mechanical forces of the circuitry are very important pathophysiological mechanisms, likely leading to neutrophil activation and the production of neutrophil extracellular traps (NETs). NETs may have the potential to cause organ damage, generating interest in their study as potential therapeutic targets for ECMO-related acute organ injury. Therefore, this article comprehensively summarized the mechanism of neutrophils activation and NETs formation following ECMO treatment and their actions on acute organ injury.

Utility of cephalic drains in infants receiving extracorporeal membrane oxygenation

INTRODUCTION

The addition of cephalic drains (CDs) in extracorporeal membrane oxygenation (ECMO) to augment venous drainage may offer benefit, though their use is varied. Our objective was to describe our institution's experience with CDs including flow rates and patency. We also compared complication rates between patients with and without a CD.

METHODS

This retrospective cohort study included infants <12 months of age cannulated for ECMO between January 1, 2010 and September 30, 2019 at a single institution. Flow data were obtained for those with a CD. Demographic and complication rates were obtained for all.

RESULTS

Of 264 patients in the final cohort, 220 (83%) had a CD of which 93.2% remained patent to decannulation. CDs typically provided 30% or more of ECMO flow throughout the ECMO run. The median time to CD clot was 139 h (range 48-635 h). Patients with a clotted CD had longer ECMO runs than those whose CD remained patent (median 382 h [IQR 217-538] vs 139 h [IQR 91-246], p < 0.001). Survival to discharge was lower for those with clotted versus patent CD (14% vs 70%, p < 0.001). Mechanical complications were more common in patients with CD (p = 0.005). Seizures were more common in those without a CD (p = 0.021).

CONCLUSIONS

In this cohort, the majority of CDs placed remained patent at decannulation and provided substantial additional venous drainage. Mechanical problems were common in patients with CDs, but without clinical sequelae. Further study is warranted to elucidate CD impact on short- and long-term outcomes.

COVID–19呼吸不全に対して3本目のカニューレを用いたVV–V ECMO管理(Role of triple cannulation venovenous extracorporeal membrane oxygenation in patients with coronavirus disease)

A 32–year–old man with dry cough was admitted to a hospital for suspected coronavirus disease–induced pneumonia. The SARS–CoV–2 PCR test showed positive results on day 3 after symptom onset. Mechanical ventilation and venovenous extracorporeal membrane oxygenation (VV ECMO) were initiated for respiratory function deterioration on day 8 after symptom onset. However, ECMO did not maintain adequate oxygenation, and ventilator settings did not allow lung rest. Therefore, secondary ECMO transport was performed, and the patient was transferred to our center via ECMOnet. The reduced oxygenation level was attributed to the use of a small drainage cannula with consequently reduced ECMO circulation. Replacement of the small drainage cannula was unsafe; therefore, an additional drainage cannula was inserted, and the ECMO configuration was switched to VV–V ECMO, which established sufficient ECMO circulation and improved his oxygenation levels, and ventilator settings were modified for lung rest. He was weaned off ECMO on day 14, and retransferred to the previous hospital on day 21 after symptom onset. Selection of a drainage cannula of optimal size is important in patients who receive VV ECMO support. Conversion of a VV ECMO to VV–V ECMO configuration is useful in cases of insufficient ECMO blood flow.

ECMO and Right Ventricular Failure: Review of the Literature

Right ventricular (RV) failure is the inability of the RV to maintain sufficient cardiac output in the setting of adequate preload, due to either intrinsic injury to the RV or increased afterload. Medical treatment of RV failure should include optimizing preload, augmenting contractility with vasopressors and inotropes, and considering inhaled pulmonary vasodilators. However, when medical therapies are insufficient, mechanical circulatory support (MCS) is needed to maintain systemic and RV perfusion. The data on MCS for isolated RV failure are limited, but extracorporeal membrane oxygenation (ECMO) appears to be the most efficient and effective modality. For patients with isolated RV failure from acute hypoxemic respiratory failure, veno-venous (VV) ECMO is an appropriate initial configuration, even if the patient is in shock. With primary RV injury or RV failure with concomitant left ventricle (LV) failure, however, venoarterial (VA) ECMO is indicated. Both modalities provide indirect support to the RV by reducing preload, reducing RV wall tension, and delivering oxygenated blood to the coronary circulation. Peripheral cannulation is required in VV-ECMO and is most commonly used in VA-ECMO, allowing for rapid cannulation even in emergencies. Changes in pulsatility on an arterial catheter waveform can indicate changes in clinical status including changes in myocardial function, inadequate preload, worsening RV failure, and excessive VA-ECMO support leading to an elevated LV afterload. Myocardial function may be improved by titration of inotropes or vasodilators, utilization of an Impella or an intra-aortic balloon counterpulsation support devices, or by changes in VA-ECMO support.

Hybrid extracorporeal membrane oxygenation

Veno-venous (VV) and veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) therapy is widely used in critically ill patients with refractory cardiogenic shock and cardiac arrest or suffering from severe respiratory failure. Besides traditional ECMO cannulation, changes in patients' conditions or the occurrence of specific complications (i.e., cerebral hypoxia or left ventricular dilation) may require modifications in cannulation strategies or the combination of ECMO with additional invasive or minimally invasive procedures, to improve organ function and ECMO efficiency. In this review, we described all these "hybrid" approaches, such as the addition of a third or fourth ECMO cannula to improve venous drainage and/or optimize systemic hemodynamics/oxygenation, or the implementation of surgical or percutaneous unloading of the left ventricle (LV), to reduce cardiac dilation and pulmonary edema. Although few data are still available about the effectiveness of such interventions, clinicians should be aware of these advances in ECMO management to improve the management of more complex cases.

Cannulation strategies for percutaneous extracorporeal membrane oxygenation in adults

Extracorporeal membrane oxygenation (ECMO) has revolutionized treatment of severe isolated or combined failure of lung and heart. Due to remarkable technical development the frequency of use is growing fast, with increasing adoption by interventional cardiologists independent of cardiac surgery. Nevertheless, ECMO support harbors substantial risk such as bleeding, thromboembolic events and infection. Percutaneous ECMO circuits usually comprise cannulation of two large vessels ('dual' cannulation), either veno-venous for respiratory and veno-arterial for circulatory support. Recently experienced centers apply more advanced strategies by cannulation of three large vessels ('triple' cannulation), resulting in veno-veno-arterial or veno-arterio-venous cannulation. While the former intends to improve drainage and unloading, the latter represents a very potent method to provide circulatory and respiratory support at the same time. As such triple cannulation expands the field of application at the expense of increased complexity of ECMO systems. Here, we review percutaneous dual and triple cannulation strategies for different clinical scenarios of the critically ill. As there is no unifying terminology to date, we propose a nomenclature which uses "A" and all following letters for supplying cannulas and all letters before "A" for draining cannulas. This general and unequivocal code covers both dual and triple ECMO cannulation strategies (VV, VA, VVA, VAV). Notwithstanding the technical evolution, current knowledge of ECMO support is mainly based on observational experience and mostly retrospective studies. Prospective controlled trials are urgently needed to generate evidence on safety and efficacy of ECMO support in different clinical settings.

Prevention of limb ischemia and edema during peripheral venoarterial extracorporeal membrane oxygenation in adults

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is a mechanical circulatory support indicated for the advanced treatment of refractory heart failure. The cannulation of the femoral vessels may be complicated by distal limb ischemia by arterial hypoperfusion and severe edema by venous obstruction. We describe a modified cannulation technique in order to prevent ischemia and edema of the inferior limb during VA-ECMO.

Challenges to cannulation for extracorporeal support in neonates with right-sided congenital diaphragmatic hernia

Right-sided diaphragmatic defects represent less than 20% of all congenital diaphragmatic hernias (CDH). Recent data suggest that right CDH (R-CDH) may carry a disproportionately high morbidity as well as increased rates of extracorporeal support when compared with left CDH. Treatment of infants with R-CDH may be further complicated by anatomical distortion unique to right-sided defects. We report 2 cases of azygous vein cannulation in neonates with large isolated R-CDH. Both infants had postnatal deteriorations within 48 hours, met our criteria for extracorporeal membrane oxygenation (ECMO), and underwent venoarterial cannulations through the right neck. In each case, the venous cannula passed directly into the azygous vein and failed to provide adequate ECMO support. Echocardiography confirmed both cases of azygous cannulation. In one child, the right atrium was successfully cannulated after 90 minutes of extensive cannula manipulation. This child survived a 5-day ECMO course and is alive at 22-month follow-up. In the second child, despite prolonged efforts at cannula repositioning, cannulation of the right atrium was not achieved. We did not offer central cannulation because of a rapidly deteriorating clinical course, with expiration in several hours. At autopsy, a dilated azygous vein was evident as a result of inferior vena cava compression by a malpositioned liver. The possibility of azygous vein cannulation may be increased in neonates with R-CDH and has not been previously reported. When evaluating infants with R-CDH for ECMO, clinicians must recognize the possibility of azygous cannulation and its potentially lethal consequences, and should anticipate alternative venous cannulation.

Venovenous extracorporeal membrane oxygenation: the effects of proximal internal jugular cannulation

Venovenous (VV) extracorporeal membrane oxygenation (ECMO) using a double lumen catheter has become an accepted method of providing ECMO support for critically ill newborn infants. In addition, use of the cephalic jugular catheter can provide augmented venous blood flow, potentially prevent increased cerebral venous pressure, maintain cerebral venous blood flow, and increase ECMO oxygen delivery. The authors compared their experience using VV double-lumen (VVDL) ECMO with a cephalic jugular catheter with their previous experience using venoarterial (VA) ECMO. They compared 15 infants who had meconium aspiration syndrome (MAS) and 12 who had congenital diaphragmatic hernia (CDH) treated with VVDL ECMO with a cephalic jugular catheter with the same number of infants with each condition treated with VA ECMO (historical controls). There were no significant differences between the groups with respect to birth weights, oxygen indexes before ECMO, of ECMO flows at 4 and 24 hours. For infants with MAS treated with VVDL ECMO, the overall duration of ECMO support was significantly shorter (63 hours VVDLv 118 hours VA; P = .001), and the average cephalic flow was 33 mL/kg for infants treated with VVDL support. For infants with CDH, there were no differences in any of the variables evaluated, including total duration (100 hours VVDLv 128 hours VA; P = .06 [NS]), and the average cephalic flow was 39 mL/kg for infants treated with VVDL support. The venous oxygen content was significantly lower in infants with MAS treated with VVDL ECMO than for historical controls treated with VA ECMO at 4 hours of ECMO support (15.8 v 16.7; P < or = .05). No other significant differences were noted for any of the calculated oxygen transport variables comparing VVDL with VA ECMO infants with CDH treated with VVDL ECMO were extubated sooner than those treated with VA ECMO (10.3 days VVDL v 15.4 days VA; P = 048). In addition, there was no significant difference in the overall incidence of complications or death. This experience suggests that VVDL ECMO using a cephalic jugular catheter results in shorter ECMO runs and provides support that is comparable to VA ECMO for infants with CDH and MAS while avoiding carotid artery cannulation and ligation.

A second course of extracorporeal membrane oxygenation in the neonate--is there a benefit?

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is an effective therapy for infants with severe respiratory failure and pulmonary hypertension. In most patients once the disease reverses, it does not recur. However, in some patients pulmonary hypertension recurs and these infants meet criteria for a second course of ECMO. We evaluated the survival rate and feasibility of a second course of ECMO in neonates.

METHODS

A questionnaire was sent to all active ECMO programs that requested data about patients who received two courses of ECMO. A retrospective review of the results from responding centers was performed to evaluate indications and outcome.

RESULTS

The overall survival rate for the 58 neonates was 40%. Thirty-four patients with congenital diaphragmatic hernia had a survival rate of 47%, and 12 infants with primary persistent pulmonary hypertension had an 8% survival rate (p < 0.05). Most patients were treated with venoarterial ECMO for both courses.

CONCLUSIONS

There is a reasonable survival rate for selected neonates who are treated with a second course of ECMO. Infants with primary persistent pulmonary hypertension should be carefully examined before institution of a second course of ECMO.