Near-Infrared Spectroscopy Monitoring for Early Detection of Limb Ischemia in Patients on Veno-Arterial Extracorporeal Membrane Oxygenation

Evolution of distal limb perfusion management in adult peripheral venoarterial extracorporeal membrane oxygenation with femoral artery cannulation

Limb ischaemia is a clinically relevant complication of venoarterial extracorporeal membrane oxygenation (VA ECMO) with femoral artery cannulation. No selective distal perfusion or other advanced techniques were used in the past to maintain adequate distal limb perfusion. A more recent trend is the shift from the reactive or emergency management to the pro-active or prophylactic placement of a distal perfusion cannula to avoid or reduce limb ischaemia-related complications. Multiple alternative cannulation techniques to the distal perfusion cannula have been developed to maintain distal limb perfusion, including end-to-side grafting, external or endovascular femoro-femoral bypass, retrograde limb perfusion (e.g., via the posterior tibial, dorsalis pedis or anterior tibial artery), and, more recently, use of a bidirectional cannula. Venous congestion has also been recognized as a potential contributing factor to limb ischaemia development and specific techniques have been described with facilitated venous drainage or bilateral cannulation being the most recent, to reduce or avoid venous stasis as a contributor to impaired limb perfusion. Advances in monitoring techniques, such as near-infrared spectroscopy and duplex ultrasound analysis, have been applied to improve decision-making regarding both the monitoring and management of limb ischaemia. This narrative review describes the evolution of techniques used for distal limb perfusion during peripheral VA ECMO.

Cannula to Femoral Artery Diameter Ratio Predicts Potential Lower-Limb Ischemia in Minimally Invasive Cardiac Surgery With Femoral Cannulation

OBJECTIVE

Lower-limb ischemia is a complication of minimally invasive cardiac surgery with femoral cannulation. Herein, we verified our strategy using distal perfusion cannulation (DPC) against this complication.

METHODS

We retrospectively assessed 91 cases of aortic valve replacement with femoral cannulation between January 2019 and March 2023. DPC was applied when lower-limb tissue oxygenation index declined by ≥20%. The cannula to femoral artery diameter ratio (C/FA) was calculated by dividing the cannula size (Fr) divided by 3 by the femoral artery inner diameter (mm). Postoperative maximum creatinine kinase (CKmax), lactate dehydrogenase (LDHmax), and lactate levels were analyzed, and univariable logistic regression and receiver operating characteristic curve analyses were employed to determine DPC predictors and the cutoff C/FA for DPC, respectively. Patients without DPC were divided into 2 subgroups based on the cutoff C/FA for further comparisons.

RESULTS

DPC was required in 9 patients. Symptomatic ischemia was not observed. All laboratory data were similar in the DPC and non-DPC groups. C/FA was significantly associated with DPC (odds ratio = 1.27, 95% confidence interval: 1.09 to 1.47, P = 0.002), and the cutoff C/FA was 0.70 (sensitivity = 0.89, specificity = 0.80). In the non-DPC group, CKmax (P = 0.027) and LDHmax (P = 0.041) were significantly higher in patients with C/FA ≥0.7 (n = 16) than in those with C/FA <0.7 (n = 66).

CONCLUSIONS

Our strategy for preventing symptomatic ischemia is reasonable and could be almost achieved without DPC when C/FA is <0.7. C/FA also predicts asymptomatic potential ischemia, and proactive DPC is preferable when C/FA is ≥0.7.

Using Signal Features of Functional Near-Infrared Spectroscopy for Acute Physiological Score Estimation in ECMO Patients

Extracorporeal membrane oxygenation (ECMO) is a vital emergency procedure providing respiratory and circulatory support to critically ill patients, especially those with compromised cardiopulmonary function. Its use has grown due to technological advances and clinical demand. Prolonged ECMO usage can lead to complications, necessitating the timely assessment of peripheral microcirculation for an accurate physiological evaluation. This study utilizes non-invasive near-infrared spectroscopy (NIRS) to monitor knee-level microcirculation in ECMO patients. After processing oxygenation data, machine learning distinguishes high and low disease severity in the veno-venous (VV-ECMO) and veno-arterial (VA-ECMO) groups, with two clinical parameters enhancing the model performance. Both ECMO modes show promise in the clinical severity diagnosis. The research further explores statistical correlations between the oxygenation data and disease severity in diverse physiological conditions, revealing moderate correlations with the acute physiologic and chronic health evaluation (APACHE II) scores in the VV-ECMO and VA-ECMO groups. NIRS holds the potential for assessing patient condition improvements.

The "via dialysis circuit" external bypass technique: External femoral to femoral bypass via dialysis circuit for antegrade perfusion of the ischemic limb

A 71-year-old woman with no relevant previous medical history presented to the emergency department with cardiopulmonary arrest due to extensive myocardial infarction. Veno-arterial extracorporeal life support (ECLS) was passed through the right common femoral artery (CFA), and an Impella CP® (16-F introduction sheath, Abiomed Inc., Danvers, MA, USA) was inserted from the left CFA. Although these mechanical devices provide powerful cardiac and organ support, an occlusive large-bore sheath may induce ischemic limb complications. Antegrade flow from the contralateral sheath was circulated through the ECLS circuit, showing the improvement of antegrade left SFA. Cardiac function improved after primary percutaneous coronary intervention, but when the ECLS was terminated, antegrade left limb flow declined. Hence, we bypassed the contralateral flow via the dialysis circuit and prevented limb ischemia.

Learning objective

Although an Impella® (Abiomed Inc., Danvers, MA, USA) is useful for assisting left ventricular cardiac function, its large-bore sheath sometimes disturbs the antegrade flow, resulting in ischemic limb complications. A novel yet simple technique that involves an external bypass through the superficial femoral artery to provide antegrade perfusion to the ipsilateral limb is hereby described.

Lower Limb Ischemia in Surgical Femoral Veno-Arterial Extracorporeal Membrane Oxygenation

OBJECTIVES

To analyze the incidence, clinical impact on survival, and risk factors of lower limb ischemia (LLI) of surgical peripheral femoral venoarterial extracorporeal membrane oxygenation (VA ECMO) in the current era.

DESIGN

A retrospective analysis of the authors' institutional database of VA ECMO was performed. Patients were divided into 2 groups according to the occurrence of LLI. The primary endpoint was survival to hospital discharge. Risk factors of LLI were searched with multivariate analyses.

SETTING

University hospital.

PARTICIPANTS

Adult patients receiving peripheral VA ECMO for refractory cardiogenic shock and cardiac arrest.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

From January 2018 to December 2021, 188 patients (mean age: 52.0 ± 14.1 years; 63.8% male, 36.2% female) received peripheral VA ECMO. Male sex was more prevalent in the group without LLI (65.9% v 33.3%; p = 0.031). Twelve (6.4%) patients developed LLI during VA ECMO support (n = 6) or after VA ECMO removal (n = 6). Survival to hospital discharge was not statistically different between patients with and without LLI (50.0% v 48.3%; p = 0.571). Female sex patients were at increased risk for LLI (odds ratio 4.38, 95% CI 1.21-15.81; p = 0.024).

CONCLUSIONS

Peripheral femoral VA ECMO through a surgical approach is associated with a low LLI rate, which does not increase the risk of in-hospital mortality. The female sex is an independent risk factor for LLI.

Continuous near-infrared reflectance spectroscopy monitoring to guide distal perfusion can minimize limb ischemia surgery for patients requiring femoral venoarterial extracorporeal life support

BACKGROUND

Patients requiring femoral venoarterial (VA) extracorporeal life support (ECLS) are at risk of distal lower limb hypoperfusion and ischemia of the cannulated leg. In the present study, we evaluated the effect of using continuous noninvasive lower limb oximetry with near-infrared reflectance spectroscopy (NIRS) to detect tissue hypoxia and guide distal perfusion catheter (DPC) placement on the rates of leg ischemia requiring surgical intervention.

METHODS

We performed a retrospective analysis of patients who had undergone femoral VA-ECLS at our institution from 2010 to 2014 (pre-NIRS era) and 2017 to 2021 (NIRS era). Patients who had undergone cannulation during the 2015 to 2016 transition era were excluded. The baseline characteristics, short-term outcomes, and ischemic complications requiring surgical intervention (eg, fasciotomy, thrombectomy, amputation, exploration) were compared across the two cohorts.

RESULTS

Of the 490 patients included in the present study, 141 (28.8%) and 349 (71.2%) had undergone cannulation before and after the routine use of NIRS to direct DPC placement, respectively. The patients in the NIRS cohort had had a greater incidence of hyperlipidemia (53.7% vs 41.1%; P = .015) and hypertension (71.4% vs 60%; P = .020) at baseline, although they were less likely to have been supported with an intra-aortic balloon pump before ECLS cannulation (26.9% vs 37.6%; P = .026). These patients were also more likely to have experienced cardiac arrest (22.9% vs 7.8%; P ≤ .001) and a pulmonary cause (5.2% vs 0.7%; P = .04) as an indication for ECLS, with ECLS initiated less often for acute myocardial infarction (15.8% vs 34%; P ≤ .001). The patients in the NIRS cohort had had a smaller arterial cannula size (P ≤ .001) and a longer duration of ECLS support (5 vs 3.25 days; P ≤ .001) but significantly lower rates of surgical intervention for limb ischemia (2.6% vs 8.5%; P = .007) despite comparable rates of DPC placement (49.1% vs 44.7%; P = .427), with only two patients (1.1%) not identified by NIRS ultimately requiring surgical intervention.

CONCLUSIONS

The use of a smaller arterial cannula (≤15F) and continuous NIRS monitoring to guide selective insertion of DPCs could be a valid and effective strategy associated with a reduced incidence of ischemic events requiring surgical intervention.

Extremity fasciotomy for patients on extracorporeal membrane oxygenation is independently associated with inpatient mortality

INTRODUCTION

Extracorporeal membrane oxygenation (ECMO) maintains end-organ perfusion in critically ill patients with cardiac or respiratory failure; however, ECMO cannulation in the extremities has been associated with significant limb ischemia and risk of compartment syndrome. Current literature on ECMO and fasciotomies is limited to small single-center retrospective studies. This study aimed to (1) compare the incidence of postoperative outcomes and mortality in patients undergoing fasciotomy while on ECMO to those of non-fasciotomy ECMO patients, and (2) assess the difference in adjusted mortality risk between the two groups.

HYPOTHESIS

We hypothesized that patients undergoing fasciotomy while on ECMO would have significantly higher odds of in-hospital mortality than non-fasciotomy ECMO patients after adjustment for perioperative variables.

METHODS

We conducted a retrospective review of NIS from January 1st, 2012-September 30, 2015 for all hospitalizations involving ECMO and stratified them into two cohorts based on whether they underwent fasciotomy after ECMO. Patient baseline characteristics, in-hospital procedures, and postoperative outcomes were compared between the two cohorts. Logistic regression was used to assess in-hospital mortality risk between the two cohorts adjusting for age, sex, Elixhauser score, and perioperative procedures and non-fasciotomy perioperative morbidity.

RESULTS

There were 7,085 estimated eligible discharges between 2012 and 2015 identified, 149 (2.1%) of which underwent fasciotomy following ECMO. One hundred and thirteen of the 149 hospitalizations (77%) in the fasciotomy cohort resulted in in-hospital mortality, compared to 3,805 of the 6,936 (55%) in the non-fasciotomy cohort. There were no differences in rates of transfusion (p=0.290), length of stay (p=0.282), or discharge disposition (p=0.126) between the two cohorts. In the logistic regression model, the fasciotomy cohort had a higher odds of in-hospital mortality than non-fasciotomy cohort (OR, 2.5; 95% CI, 1.1-5.6).

DISCUSSION

Operative treatment of acute compartment syndrome for patients on ECMO therapy is associated with significantly increased mortality and morbidity. Whether fasciotomy is a marker of sickness or represents a cause-and-effect relationship is unknown and future should investigate the role of non-operative treatment of compartment syndrome on mortality in this population.

LEVEL OF EVIDENCE

III; Prognostic.

Near-Infrared Spectroscopy for Determination of Cardiac Output Augmentation in a Swine Model of Ischemia-Reperfusion Injury

CONTEXT:

Near infrared spectroscopy (NIRS) is a noninvasive tool for assessing local oxygen balance. In circulatory shock, the microcirculatory environment as measured by NIRS during resuscitation may provide additional diagnostic tools of value to the critical care physician.

HYPOTHESIS:

To assess whether a relative increase in peripheral NIRS was correlated with a clinically relevant increase in cardiac output following a fluid bolus in a swine model of shock.

METHODS AND MODELS:

Nine healthy young adult swine with median weight 80 kg (interquartile range, 75–83 kg) were anesthetized and surgically instrumented. They underwent a controlled hemorrhage of 20% of their blood volume followed by partial or complete aortic occlusion to create a variable ischemia-reperfusion injury. Next, the animals underwent four 500-mL plasmalyte boluses over 9 minutes each followed by a 6-minute pause. The animal then underwent a 25% mixed auto/homologous blood transfusion followed by four more 500 mL plasmalyte boluses over 9 minutes. Finally, the animals underwent a 25% mixed auto/homologous blood transfusion followed by an additional four rounds of 500-mL plasmalyte boluses over 9 minutes. Left thoracic limb NIRS, descending thoracic aortic flow (dAF), arterial blood pressure (MAP), central venous pressure (CVP), and mixed central venous oxygen saturation (Svo₂) were measured continuously for comparison.

RESULTS:

The area under the receiver operating curve for an increase in dAF of 10% in response to a 500 mL bolus based on a percent increase in the proximal NIRS was 0.82 with 95% CI, 0.72–0.91; Svo₂, 0.86 with 95% CI, 0.78–0.95; MAP, 0.75 with 95% CI, 0.65–0.85 and CVP, 0.64 with 95% CI, 0.53–0.76.

INTERPRETATION AND CONCLUSIONS:

A dynamic relative increase in NIRS in response to a crystalloid challenge has moderate discriminatory power for cardiac output augmentation during shock in a swine model of ischemia-reperfusion injury. NIRS performed as well as invasive measurements (Svo₂ and MAP) and better than CVP.

Arterial and venous vascular complications in patients requiring peripheral venoarterial extracorporeal membrane oxygenation

Introduction

The aim of this study was to investigate the prevalence of arterial and venous complications in patients requiring peripheral venoarterial extracorporeal membrane oxygenation (VA ECMO) and its risk factors at the time of cannulation and during extracorporeal membrane oxygenation (ECMO) support and to assess vascular complications in association with decannulation.

Material and methods

Between January 2010 to January 2020, out of 1,030 eligible patients requiring VA-ECMO, 427 with analyzable vascular screening were included. Duplex sonography and/or CT scan after decannulation were used to screen for thrombosis and pulmonary embolism as well as arterial complications. Near-infrared spectrometry (NIRS) was established at the time of cannulation and was continuously monitored during the ECMO therapy.

Results

The prevalence of venous complications was 27%. Thrombosis and pulmonary embolism were observed in 21 and 7% of patients, respectively. Pulmonary embolism was more frequently diagnosed in patients with thrombosis (22 vs. 3%, p &lt; 0.001). In multivariate analysis, cannulation in the jugular vein was determined as a risk factor for venous thrombosis in contrast to the extent of anticoagulation. The prevalence of arterial complications was 37%, mainly ischemia followed by bleeding, dissection, and compartment syndrome. Vascular surgery was necessary for 19% of the patients, of whome 1% required major amputations. A distal perfusion cannula (DPC) was implanted at cannulation in 24% of patients and secondarily in 16% of patients after cannulation as required during ECMO support. In the multivariate analysis, risk factors for leg ischemia at the time of cannulation were elevated D-dimers, lower NIRS on the cannulated leg, and lack of a DPC. The best discriminative parameter was the difference in NIRS between the non-cannulated leg and the cannulated leg. In contrast, during ECMO support, only the lack of a DPC was associated with leg ischemia. A similar rate of complications associated with decannulation, mainly arterial thrombosis, ischemia, or bleeding, was seen with percutaneous and surgical approaches (18 vs. 17%, p = 0.295).

Conclusion

Patients requiring VA ECMO should be routinely screened for vascular complications. The decision to insert a DPC should be evaluated individually. However, NIRS monitoring of the cannulated leg and the non-cannulated leg is essential to identify the legs at risk for critical ischemia. As complications associated with decannulation were equally distributed between percutaneous and surgical approaches, the applied method may be chosen according to local experience.

Use of a Reperfusion Cannula for Acute Limb Ischemia in a Patient with Carotid Artery Extracorporeal Membrane Oxygenation Cannulation

Acute limb ischemia is a rare but potentially devastating event in a critically ill patient. In the pediatric population, limb ischemia is usually related to iatrogenic vascular damage and arterial thrombus formation secondary to arterial catheter placement. Children who have undergone femoral artery cannulation for venoarterial extracorporeal membrane oxygenation (VA-ECMO) are particularly at risk for this complication. In these cases, there have been reports of the successful use of a percutaneous limb reperfusion cannula to prevent or treat limb ischemia. We present a case of an 18 month old female who required VA-ECMO via carotid artery cannulation for viral myocarditis and subsequently developed acute lower limb ischemia related to a thrombus from an indwelling femoral arterial catheter in place for hemodynamic monitoring. This case highlights the usage of a distal reperfusion cannula and extracorporeal membrane oxygenation (ECMO) circuit for a novel purpose, which coupled with near infrared spectroscopy (NIRS) monitoring successfully re-established blood flow to the ischemic limb.

SEDAR/SECCE ECMO management consensus document

ECMO is an extracorporeal cardiorespiratory support system whose use has been increased in the last decade. Respiratory failure, postcardiotomy shock, and lung or heart primary graft failure may require the use of cardiorespiratory mechanical assistance. In this scenario perioperative medical and surgical management is crucial. Despite the evolution of technology in the area of extracorporeal support, morbidity and mortality of these patients continues to be high, and therefore the indication as well as the ECMO removal should be established within a multidisciplinary team with expertise in the area. This consensus document aims to unify medical knowledge and provides recommendations based on both the recent bibliography and the main national ECMO implantation centres experience with the goal of improving comprehensive patient care.

Ankle-brachial index to monitor limb perfusion in patients with femoral venoarterial extracorporeal membrane oxygenation

BACKGROUND

Limb ischemia is a major complication of femoral venoarterial extracorporeal membrane oxygenation (VA-ECMO). Use of ankle-brachial index (ABI) to monitor limb perfusion in VA-ECMO has not been described. We report our experience monitoring femoral VA-ECMO patients with serial ABI and the relationships between ABI and near infrared spectroscopy (NIRS).

METHODS

This is a retrospective single-center review of consecutive adult patients placed on femoral VA-ECMO between January 2019 and October 2019. Data were collected on patients with paired ABI and NIRS values. Relationships between NIRS and ABI of the cannulated (E-NIRS and E-ABI) and non-cannulated legs (N-NIRS and N-ABI) along with the difference between legs (d-NIRS and d-ABI) were determined using Pearson correlation.

RESULTS

Overall, 22 patients (mean age 56.5 ± 14.0 years, 72.7% male) were assessed with 295 E-ABI and E-NIRS measurements, and 273 N-ABI and N-NIRS measurements. Mean duration of ECMO support was 129.8 ± 78.3 h. ECMO-mortality was 13.6% and in-hospital mortality was 45.5%. N-ABI and N-NIRS were significantly higher than their ECMO counterparts (ABI mean difference 0.16, 95% confidence interval [CI]: 0.13-0.19, p < .0001; NIRS mean difference 2.51, 95% CI: 1.48-3.54, p < .0001). There was no correlation between E-ABI versus E-NIRS (r = .032, p = .59), N-ABI versus N-NIRS (r = .097, p = .11), or d-NIRS versus d-ABI (r = .11, p = .069).

CONCLUSION

ABI is a quantitative metric that may be used to monitor limb perfusion and supplement clinical exams to identify limb ischemia in femorally cannulated VA-ECMO patients. More studies are needed to characterize the significance of ABI in femoral VA-ECMO and its value in identifying limb ischemia in this patient population.

Bedside angiography of distal perfusion catheter for veno-arterial extracorporeal membrane oxygenation

BACKGROUND

The aim of this study was to evaluate the ipsilateral lower extremity (ILE) outcomes of patients who underwent bedside angiography via the distal perfusion catheter while on femoral veno-arterial extracorporeal membrane oxygenation (VA ECMO).

METHODS

This is a retrospective analysis of all patients placed on VA ECMO at a single center from January 2017 to December 2019 who underwent bedside angiography via the distal perfusion catheter.

RESULTS

Twenty-four patients underwent bedside angiography via the distal perfusion catheter after being placed on VA ECMO. A vasodilator was directly administered in three patients for suspected spasm. One patient had distal thrombus and underwent thrombectomy and fasciotomy. One patient had a dislodged catheter and underwent thrombectomy, fasciotomy, and replacement of the catheter. One patient had severe ILE ischemia, however was not intervened upon due to critical acuity. Finally, one patient had inadvertent placement in the saphenous vein and had a new catheter placed in the SFA. No patients underwent amputation. Ultimately, 21 patients (87.5%) had no ILE compromise at the end their ECMO course. Survival to decannulation was 66.7% (n = 16).

CONCLUSIONS

Bedside angiography of the distal perfusion catheter is feasible and can be a useful adjunct in informing the need for further intervention to the ILE.

CLASSIFICATIONS

extracorporeal membrane oxygenation, ischemia.

Alternative option for limb reperfusion cannula placement for percutaneous femoral veno-arterial ECMO

Veno-arterial extracorporeal membrane oxygenation (VA ECMO) is an established last line support for severe, acute cardiorespiratory failure. In the case of VA ECMO, peripheral cannulation via the femoral vessels is often advantageous when compared with the alternative central cannulation, and is associated with better clinical outcomes. One of the specific potential complications of peripheral femoral arterial cannulation for ECMO, however, is ipsilateral distal lower limb ischemia; a consideration especially when cannulating the vessel directly, as distal limb perfusion is invariably compromised by an occlusive effect of the arterial cannula within the femoral artery. The gold standard technique for lower limb reperfusion is a separate size 6-7 Fr cannula inserted proximally into the femoral artery, just below the insertion point of the ECMO return cannula, and connected directly to the ECMO circuit so that the blood flow is also directed distally to perfuse the entire limb. This functions well whether the ECMO cannula has been placed percutaneously or by surgical cut-down. Although proximal femoral arterial placement of the reperfusion cannula is the established and preferred technique, there are many technical challenges which may preclude its placement. Local haematoma or bleeding post ECMO insertion, peripheral vascular disease, constricted vasculature in severely shocked patients, or patient obesity are all common reasons why placement of the proximal reperfusion cannula may be difficult, or impossible. In such instances, our retrograde perfusion technique may maintain limb perfusion and may even be limb saving for patients on VA ECMO support.

Managing Patients With Short-Term Mechanical Circulatory Support: JACC Review Topic of the Week

The use of mechanical circulatory support for patients presenting with cardiogenic shock is rapidly increasing. Currently, there is only limited and conflicting evidence available regarding the role of the Impella (a microaxial, continuous-flow, short-term, left or right ventricular assist device) in cardiogenic shock; further randomized trials are needed. Patient selection, timing of implantation, and post-implantation management in the cardiac intensive care unit are crucial elements for success. Particular challenges at the bedside include the practical management of anticoagulation, evaluation of correct device position, and the approach to use in a patient with signs of insufficient hemodynamic support. Profound knowledge of these issues is required to enable the maximal potential of the device. This review provides a comprehensive overview of the short-term assist device and describes a practical approach to optimize care for patients supported with the device.

Suspected Lower Extremity Ischemia After End-to-Side Femoral Arterial Grafting for VA-ECMO

Lower extremity ischemic complications are frequently encountered after femoral cannulation for venoarterial extracorporeal membrane oxygenation (VA-ECMO). Many are attributed to mechanical obstruction of distal arterial blood flow related to intraluminal positioning of the arterial cannula. Routine use of distal perfusion catheters is ineffective at eliminating the development of these serious complications. Side- arm grafting instead of direct arterial cannulation is suggested as an alternative. Here, the authors present a case wherein a patient developed suspected lower extremity ischemia from hyperperfusion after femoral VA-ECMO cannulation during use of an arterial side- arm graft, calling into question the benefits of this cannulation strategy.

Limb ischemia and bleeding in patients requiring venoarterial extracorporeal membrane oxygenation

OBJECTIVE

Acute limb ischemia (ALI) and cannulation site bleeding are frequent complications of venoarterial (VA) extracorporeal membrane oxygenation (ECMO) and are associated with worse outcomes. The goals of this study were to assess our rates of ECMO-related ALI and bleeding and to evaluate the efficacy of strategies to prevent them, such as distal perfusion cannula (DPC) and ultrasound-guided cannulation.

METHODS

This is a single-center retrospective cohort study of adult patients placed on peripheral VA-ECMO at a tertiary medical center between 2014 and 2018. ALI was defined as new ischemia of the extremity ipsilateral to arterial cannulation. Significant cannulation site bleeding was defined as excessive bleeding requiring intervention (eg, transfusion or reoperation). Univariate analyses were used to identify factors associated with ALI, bleeding, and in-hospital mortality.

RESULTS

During the study period, 105 patients were placed on peripheral VA-ECMO (61.3% female; mean age, 54.9 ± 14.8 years). Nearly half (46.6%) had ECMO implantation in an extracorporeal cardiopulmonary resuscitation setting and 37 (44.0%) had a DPC. Average duration of support was 5.6 ± 5.0 days. Overall in-hospital mortality and death on ECMO support were 65.1% and 50%, respectively. ALI occurred in 21 (20%) and cannulation-related bleeding occurred in 24 (22.9%) patients who were treated with a total of 27 procedures, including thromboembolectomy (22.2%), vascular repair (18.5%), and fasciotomy (25.9%). On univariate analysis, cannulation in the operating room (odds ratio [OR], 0.25; 95% confidence interval [CI], 0.08-0.77; P = .02) was associated with decreased risk of ALI, whereas cannulation in the operating room (OR, 2.65; 95% CI, 1.09-6.45; P = .03) and cutdown approach (OR, 4.96; 95% CI, 2.32-10.61; P < .0001) were associated with increased risk of bleeding. Ultrasound-guided placement was associated with decreased risk of bleeding (OR, 0.81; 95% CI, 0.04-0.84; P = .03). DPC was not associated with either ALI (P = .47) or bleeding (P = .06). ALI (OR, 2.68; 95% CI 1.03-6.98; P = .04), age (OR, 1.94; 95% CI, 1.03-3.69; P = .04), and worse baseline heart failure (OR, 2.01; 95% CI, 1.02-3.97; P = .04) were associated with greater risk of in-hospital mortality. Ultrasound-guided cannulation (OR, 0.41; 95% CI, 0.20-0.87; P = .02) was associated with decreased risk of in-hospital mortality.

CONCLUSIONS

ALI and significant bleeding are common occurrences after peripheral VA-ECMO cannulation. Whereas DPC placement did not significantly decrease risk of ALI, ultrasound-guided cannulation decreased the risk of bleeding. Cannulation in the operating room is associated with decreased risk of ALI at the expense of increased risk of bleeding. ALI, older age (≥65 years), and worse heart failure increased risk of in-hospital mortality.

Hemodynamic monitoring in patients with venoarterial extracorporeal membrane oxygenation

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is an effective mechanical circulatory support modality that rapidly restores systemic perfusion for circulatory failure in patients. Given the huge increase in VA-ECMO use, its optimal management depends on continuous and discrete hemodynamic monitoring. This article provides an overview of VA-ECMO pathophysiology, and the current state of the art in hemodynamic monitoring in patients with VA-ECMO.

Cerebral Oxygenation as a Monitoring Parameter for Mortality During Venoarterial Extracorporeal Membrane Oxygenation

There are no recommended guidelines for monitoring parameters during venoarterial extracorporeal membrane oxygenation (V-A ECMO). We evaluated whether regional cerebral oxygen saturation (rScO2) could be a monitoring parameter for mortality during V-A ECMO. We retrospectively searched our database for adult patients who underwent V-A ECMO between April 2015 and October 2016 and identified 21 patients with rScO2 data. Their baseline and clinical characteristics during the first 7 days (vital signs, arterial blood gas results, ECMO variables, rScO2, Swan-Ganz catheter parameters, transthoracic echocardiography parameters, and outcomes) were collected and evaluated for associations with 28 day mortality. The survivor group (12 patients, 57.1%) had higher rScO2 values and lower lactate levels, compared with the nonsurvivor group (nine cases, 42.9%) during the first 7 days. The areas under the receiver operating characteristics curves were 0.87 for right rScO2 (p < 0.001) and 0.86 for left rScO2 (p < 0.001). The optimal cutoff values for right and left rScO2 were 58% (sensitivity: 78.7%, specificity: 83.3%) and 57% (sensitivity: 80.0%, specificity: 70.8%), respectively. Kaplan-Meier analysis revealed that the risks of 28 day mortality were higher among patients with a right rScO2 of <58% and a left rScO2 of <57%, compared with patients with a right rScO2 of ≥58% and a left rScO2 of ≥57% (both, p < 0.001). We suggest that rScO2 may be used as a monitoring parameter for 28 day mortality among patients undergoing V-A ECMO.

Hemodynamic monitoring in the extracorporeal membrane oxygenation patient

PURPOSE OF REVIEW

Hemodynamic monitoring in ECMO patients requires familiarity with the underlying pathophysiology and circulatory mechanics of extracorporeal flow. This review discusses the various monitoring modalities relevant to the management of patients on venovenous ECMO (VV ECMO) and venoarterial (VA ECMO). We emphasize tools to judge the adequacy of perfusion, predict the response to fluid boluses, measure right ventricular function, assess left ventricular distention (for VA ECMO), and monitor the process of weaning from ECMO. We emphasize how differences between VV ECMO and VA ECMO are reflected in distinct approaches to monitoring.

RECENT FINDINGS

Point-of-care ultrasound and near-infrared spectroscopy can play a significant role in monitoring of global and regional perfusion.

SUMMARY

Recent literature in hemodynamic monitoring of ECMO patients is discussed, with comparison of VV ECMO and VA ECMO. Many common monitoring tools lack validity during ECMO: by taking into account the unique physiology of the ECMO circulation, selected methods can aid in the care of these complex patients.

Contemporary Comprehensive Monitoring of Veno-arterial Extracorporeal Membrane Oxygenation Patients

The use of veno-arterial extracorporeal membrane oxygenation (VA ECMO) has increased substantially over the past few decades. Today's clinicians now have a powerful means with which to salvage a growing population of patients at risk for cardiopulmonary collapse. At the same time, patients supported with VA ECMO have become increasingly more complex. The successful use of VA ECMO depends not only on selecting the appropriate patients, but also on effectively navigating a potential torrent of device- and patient-related complications until ECMO is no longer needed. A multitude of monitoring tools are now available to help the treatment team determine the adequacy of care, to detect problems, and to anticipate recovery. Monitoring with devices such as the Swan-Ganz catheter, transthoracic and transesophageal echocardiography, chest radiography, and near-infrared spectroscopy can provide useful information to complement routine clinical care. Leveraging data derived from the ECMO circuit itself also can be instrumental in both evaluating the sufficiency of support and troubleshooting complications. Each of these tools, however, has its own unique sets of limitations and liabilities. A thorough understanding of these risks and benefits is critical to the contemporary care of the individual managed with VA ECMO. In addition, more research is needed to establish optimal evidence-based care pathways and best-practice principles for using these devices to improve patient outcomes.

Medical Optimization and Liberation of Adult Patients From VA-ECMO

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) can be an efficacious cardiopulmonary support for adults as rescue from refractory cardiogenic shock. It is best employed as a bridging strategy to recovery or alternative support rather than sustained, long-term mechanical circulatory support. The purpose of this paper is to discuss strategies to optimize patient management on VA-ECMO and approaches to promote successful separation from support. Rapid medical optimization will assist in reducing the time on VA-ECMO, thereby improving the likelihood of patient salvage. Suitably trained physicians and personnel, guided by structured protocols, can promote excellence in team care and provision of consistent management. Focusing on anticoagulation, careful neurologic monitoring, prevention of leg ischemia, awareness of differential hypoxemia, optimizing mechanical ventilation, identifying and timely intervention for left-ventricular distension (LVD), along with a strategic weaning algorithm, can prevent significant morbidity and mortality. LVD physiology, diagnosis, and risk factors are reviewed. Indications for LV decompression, along with medical and mechanical management options, are elucidated.

Limb ischemia in peripheral veno-arterial extracorporeal membrane oxygenation: a narrative review of incidence, prevention, monitoring, and treatment

Veno-arterial extracorporeal membrane oxygenation (V-A ECMO) is an increasingly adopted life-saving mechanical circulatory support for a number of potentially reversible or treatable cardiac diseases. It is also started as a bridge-to-transplantation/ventricular assist device in the case of unrecoverable cardiac or cardio-respiratory illness. In recent years, principally for non-post-cardiotomy shock, peripheral cannulation using the femoral vessels has been the approach of choice because it does not need the chest opening, can be quickly established, can be applied percutaneously, and is less likely to cause bleeding and infections than central cannulation. Peripheral ECMO, however, is characterized by a higher rate of vascular complications. The mechanisms of such adverse events are often multifactorial, including suboptimal arterial perfusion and hemodynamic instability due to the underlying disease, peripheral vascular disease, and placement of cannulas that nearly occlude the vessel. The effect of femoral artery damage and/or significant reduced limb perfusion can be devastating because limb ischemia can lead to compartment syndrome, requiring fasciotomy and, occasionally, even limb amputation, thereby negatively impacting hospital stay, long-term functional outcomes, and survival. Data on this topic are highly fragmentary, and there are no clear-cut recommendations. Accordingly, the strategies adopted to cope with this complication vary a great deal, ranging from preventive placement of antegrade distal perfusion cannulas to rescue interventions and vascular surgery after the complication has manifested.This review aims to provide a comprehensive overview of limb ischemia during femoral cannulation for VA-ECMO in adults, focusing on incidence, tools for early diagnosis, risk factors, and preventive and treating strategies.

Structured review of post-cardiotomy extracorporeal membrane oxygenation: Part 2-pediatric patients

Veno-arterial extracorporeal membrane oxygenation (ECMO) is established therapy for short-term circulatory support for children with life-treating cardiorespiratory dysfunction. In children with congenital heart disease (CHD), ECMO is commonly used to support patients with post-cardiotomy shock or complications including intractable arrhythmias, cardiac arrest, and acute respiratory failure. Cannulation configurations include central, when the right atrium and aorta are utilized in patients with recent sternotomy, or peripheral, when cannulation of the neck or femoral vessels are used in non-operative patients. ECMO can be used to support any form of cardiac disease, including univentricular palliated circulation. Although veno-arterial ECMO is commonly used to support children with CHD, veno-venous ECMO has been used in selected patients with hypoxemia or ventilatory failure in the presence of good cardiac function. ECMO use and outcomes in the CHD population are mainly informed by single-center studies and reports from collated registry data. Significant knowledge gaps remain, including optimal patient selection, timing of ECMO deployment, duration of support, anti-coagulation, complications, and the impact of these factors on short- and long-term outcomes. This report, therefore, aims to present a comprehensive overview of the available literature informing patient selection, ECMO management, and in-hospital and early post-discharge outcomes in pediatric patients treated with ECMO for post-cardiotomy cardiorespiratory failure.