An exploration of intensive care nurses' perceptions of workload in providing extracorporeal membrane oxygenation (ECMO) support: A descriptive qualitative study

BACKGROUND

There is increasing use of extracorporeal membrane oxygenation (ECMO) in intensive care, where nurses provide the majority of the required ongoing care of cannulas, circuit, and console. Limited evidence currently exists that details nursing perspectives, experiences, and challenges with workload in the provision of ECMO care.

OBJECTIVE

The objective of this study was to investigate intensive care nurses' perceptions of workload in providing specialist ECMO therapy and care in a high-volume ECMO centre.

METHODS

The study used a qualitative descriptive methodology through semistructured interviews. Data were analysed using an inductive thematic analysis approach following Braun and Clarke's iterative process. This study was conducted in an intensive care unit within an Australian public, quaternary, university-affiliated hospital, which provides specialist state-wide service for ECMO.

FINDINGS

Thirty ECMO-specialist trained intensive care nurses were interviewed. This study identified three key themes: (i) opportunity; (ii) knowledge and responsibilities; and (iii) systems and structures impacting on intensive care nurses' workload in providing ECMO supportive therapy.

CONCLUSIONS

Intensive care nurses require advanced clinical and critical thinking skills. Intensive care nurses are motivated and engaged to learn and acquire ECMO skills and competency as part of their ongoing professional development. Providing bedside ECMO management requires constant monitoring and surveillance from nurses to care for the one of the most critically unwell patient populations in the intensive care unit setting. As such, ECMO nursing services require a suitably trained and educated workforce of intensive care trained nurses. ECMO services provide clinical development opportunities for nurses, increase their scope of practice, and create advanced practice-specialist roles.

Pre-hospital ECPR in an Australian metropolitan setting: a single-arm feasibility assessment-The CPR, pre-hospital ECPR and early reperfusion (CHEER3) study

INTRODUCTION

Survival from refractory out of hospital cardiac arrest (OHCA) without timely return of spontaneous circulation (ROSC) utilising conventional advanced cardiac life support (ACLS) therapies is dismal. CHEER3 was a safety and feasibility study of pre-hospital deployed extracorporeal membrane oxygenation (ECMO) during cardiopulmonary resuscitation (ECPR) for refractory OHCA in metropolitan Australia.

METHODS

This was a single jurisdiction, single-arm feasibility study. Physicians, with pre-existing ECMO expertise, responded to witnessed OHCA, age < 65 yrs, within 30 min driving-time, using an ECMO equipped rapid response vehicle. If pre-hospital ECPR was undertaken, patients were transported to hospital for investigations and therapies including emergent coronary catheterisation, and standard intensive care (ICU) therapy until either cardiac and neurological recovery or palliation occurred. Analyses were descriptive.

RESULTS

From February 2020 to May 2023, over 117 days, the team responded to 709 "potential cardiac arrest" emergency calls. 358 were confirmed OHCA. Time from emergency call to scene arrival was 27 min (15-37 min). 10 patients fulfilled the pre-defined inclusion criteria and all were successfully cannulated on scene. Time from emergency call to ECMO initiation was 50 min (35-62 min). Time from decision to ECMO support was 16 min (11-26 min). CPR duration was 46 min (32-62 min). All 10 patients were transferred to hospital for investigations and therapy. 4 patients (40%) survived to hospital discharge neurologically intact (CPC 1/2).

CONCLUSION

Pre-hospital ECPR was feasible, using an experienced ECMO team from a single-centre. Overall survival was promising in this highly selected group. Further prospective studies are now warranted.

Anti-Factor-Xa and Activated Partial Thromboplastin Time Concordance and Outcomes in Adults Undergoing Extracorporeal Membrane Oxygenation: A Secondary Analysis of the Pilot Low-Dose Heparin in Critically Ill Patients Undergoing Extracorporeal Membrane Oxygenation Randomized Trial

OBJECTIVES

To determine the concordance between activated partial thromboplastin time (aPTT) and anti-factor-Xa (anti-Xa) in adults undergoing extracorporeal membrane oxygenation (ECMO) and to identify the factors associated with discordant paired aPTT/anti-Xa.

DESIGN

Pre-planned secondary analysis of the Low-Dose Heparin in Critically Ill Patients Undergoing Extracorporeal Membrane Oxygenation pilot randomized unblinded, parallel-group controlled trial.

SETTING

Two ICUs in two university hospitals.

PATIENTS

Thirty-two critically ill patients who underwent ECMO and who had at least one paired aPTT and anti-Xa assay performed at the same time.

INTERVENTIONS

We analyzed the concordance between aPTT and anti-Xa and identified factors associated with discordant paired aPTT/anti-Xa based on their respective therapeutic ranges. We also compared biological parameters between heparin resistance episode and no heparin resistance.

MEASUREMENTS AND MAIN RESULTS

Of the 32 patients who were included in this study, 24 (75%) had at least one discordant paired aPTT/anti-Xa. Of the 581 paired aPTT/anti-Xa that were analyzed, 202 were discordant. The aPTT was relatively lower than anti-Xa in 66 cases (32.7%) or relatively higher than anti-Xa in 136 cases (67.3%). Thirty-three heparin resistance episodes were identified in six patients (19%).

CONCLUSIONS

In these critically ill patients undergoing ECMO, one third of paired aPTT/anti-Xa measures was discordant. Coagulopathy and heparin resistance might be the reasons for discordance. Our results support the potential importance of routinely monitoring both tests in this setting.

Modified indirect calorimetry for patients on venoarterial extracorporeal membrane oxygenation: a pilot feasibility study

BACKGROUND/OBJECTIVES

Traditional indirect calorimetry is unable to capture complete gas exchange in patients receiving venoarterial extracorporeal membrane oxygenation (VA ECMO). We aimed to determine the feasibility of using a modified indirect calorimetry protocol in patients receiving VA ECMO, report measured energy expenditure (EE) and compare EE to control critically ill patients.

SUBJECTS/METHODS

Mechanically ventilated adult patients receiving VA ECMO were included. EE was measured within 72 h of VA ECMO commencement (timepoint one [T1]) and on approximately day seven of Intensive Care Unit (ICU) admission (timepoint two [T2]). Traditional indirect calorimetry via the ventilator was combined with calculations of oxygen consumption and carbon dioxide production derived from pre- and post-ECMO membrane blood gas analyses. Completion of ≥60% EE measurements was deemed feasible. Measured EE was compared between T1 and T2 and to control patients not receiving VA ECMO. Data is presented as n(%) and median[interquartile range (IQR)].

RESULTS

Twenty-one patients were recruited; 16(76%) male, aged 55[42-64] years. The protocol was feasible to complete at T1 (14(67%)) but not at T2 (7(33%)) due to predominantly ECMO decannulation, extubation or death. EE was 1454[1213-1860] at T1 and 1657[1570-2074] kcal/d at T2 (P = 0.043). In patients receiving VA ECMO versus controls, EE was 1577[1434-1801] versus 2092[1609-2272] kcal/d, respectively (P = 0.056).

CONCLUSION

Modified indirect calorimetry is feasible early in admission to ICU but is not possible in all patients receiving VA ECMO, especially later in admission. EE increases during the first week of ICU admission but may be lower than EE in control critically ill patients.

Incidence of death or disability at 6 months after extracorporeal membrane oxygenation in Australia: a prospective, multicentre, registry-embedded cohort study

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is an invasive procedure used to support critically ill patients with the most severe forms of cardiac or respiratory failure in the short term, but long-term effects on incidence of death and disability are unknown. We aimed to assess incidence of death or disability associated with ECMO up to 6 months (180 days) after treatment.

METHODS

This prospective, multicentre, registry-embedded cohort study was done at 23 hospitals in Australia from Feb 15, 2019, to Dec 31, 2020. The EXCEL registry included all adults (≥18 years) in Australia who were admitted to an intensive care unit (ICU) in a participating centre at the time of the study and who underwent ECMO. All patients who received ECMO support for respiratory failure, cardiac failure, or cardiac arrest during their ICU stay were eligible for this study. The primary outcome was death or moderate-to-severe disability (defined using the WHO Disability Assessment Schedule 2.0, 12-item survey) at 6 months after ECMO initiation. We used Fisher's exact test to compare categorical variables. This study is registered with ClinicalTrials.gov, NCT03793257.

FINDINGS

Outcome data were available for 391 (88%) of 442 enrolled patients. The primary outcome of death or moderate-to-severe disability at 6 months was reported in 260 (66%) of 391 patients: 136 (67%) of 202 who received veno-arterial (VA)-ECMO, 60 (54%) of 111 who received veno-venous (VV)-ECMO, and 64 (82%) of 78 who received extracorporeal cardiopulmonary resuscitation (eCPR). After adjustment for age, comorbidities, Acute Physiology and Chronic Health Evaluation (APACHE) IV score, days between ICU admission and ECMO start, and use of vasopressors before ECMO, death or moderate-to-severe disability was higher in patients who received eCPR than in those who received VV-ECMO (VV-ECMO vs eCPR: risk difference [RD] -32% [95% CI -49 to -15]; p&lt;0·001) but not VA-ECMO (VA-ECMO vs eCPR -8% [-22 to 6]; p=0·27).

INTERPRETATION

In our study, only a third of patients were alive without moderate-to-severe disability at 6 months after initiation of ECMO. The finding that disability was common across all areas of functioning points to the need for long-term, multidisciplinary care and support for surviving patients who have had ECMO. Further studies are needed to understand the 180-day and longer-term prognosis of patients with different diagnoses receiving different modes of ECMO, which could have important implications for the selection of patients for ECMO and management strategies in the ICU.

FUNDING

The National Health and Medical Research Council of Australia.

Outcomes of patients with refractory out-of-hospital cardiac arrest transported to an ECMO centre compared with transport to non-ECMO centres

Objective: To compare the outcomes of patients with refractory out-of-hospital cardiac arrest (OHCA) transported to a hospital that provides extracorporeal membrane oxygenation (ECMO) during cardiopulmonary resuscitation (ECPR) with patients transported to hospitals without ECPR capability. Design, setting: Retrospective review of patient care records in a pre-hospital and hospital setting. Participants: Adult patients with OHCA who left the scene and arrived with cardiopulmonary resuscitation in progress at 16 hospitals in Melbourne, Australia, between January 2016 and December 2019. Intervention: For selected patients transported to the ECPR centre, initiation of ECMO. Main outcome measures: Survival to hospital discharge and 12-month quality of life. Results: There were 223 eligible patients during the study period. Of 49 patients transported to the ECPR centre, 23 were commenced on ECMO. Of these, survival to hospital with good neurological recovery (Cerebral Performance Category [CPC] score 1/2) occurred in 4/23 patients. Four other patients developed return of spontaneous circulation in the ECPR centre before cannulation of whom one survived, giving overall good functional outcome at 12 months survival of 5/49 (10.2%). There were 174 patients transported to the 15 non-ECPR centres and 3/174 (2%) had good functional outcome at 12 months. After adjustment for baseline differences, the odds ratio for good neurological outcome after transport to an ECPR centre compared with a non-ECPR centre was 4.63 (95% CI, 0.97-22.11; P = 0.055). Conclusion: The survival rate of patients with refractory OHCA transported to an ECPR centre remains low. Outcomes in larger cities might be improved with shorter scene times and additional ECPR centres that would provide for earlier initiation of ECMO.

Extracorporeal membrane oxygenation and V/Q ratios: an ex vivo analysis of CO2 clearance within the Maquet Quadrox-iD oxygenator

While hypercapnia is typically well treated with modern membrane oxygenators, there are cases where respiratory acidosis persists despite maximal extracorporeal membrane oxygenation support. To better understand the physiology of gas exchange within the membrane oxygenator, CO₂ clearance within an adult Maquet Quadrox-iD oxygenator was evaluated at varying blood CO₂ tensions and V/Q ratios in an ex vivo extracorporeal membrane oxygenation circuit. A closed blood-primed circuit incorporating two Maquet Quadrox-iD oxygenators in series was attached to a Maquet PLS Rotaflow pump. A varying blend of CO₂ and air was connected to the first oxygenator to provide different levels of pre-oxygenator blood CO₂ levels (P_vCO₂) to the second oxygenator. Varying sweep gas flows of 100% O₂ were connected to the second oxygenator to provide different V/Q ratios. Exhaust CO₂ was directly measured, and then VCO₂ and oxygenator dead space fraction (V_D/V_T) were calculated. VCO₂ increased with increasing gas flow rates with plateauing at V/Q ratios greater than 4.0. Exhaust CO₂ increased with P_vCO₂ in a linear fashion with the slope of the line decreasing at high V/Q ratios. Oxygenator dead space fraction varied with V/Q ratio-at lower ratios, dead space fraction was 0.3-0.4 and rose to 0.8-0.9 at ratios greater than 4.0. Within the Maquet Quadrox-iD oxygenator, CO₂ clearance is limited at high V/Q ratios and correlated with elevated oxygenator dead space fraction. These findings have important implications for patients requiring high levels of extracorporeal membrane oxygenation support.

Hyperoxia in patients with cardiogenic shock after myocardial infarction supported with venoarterial extracorporeal membrane oxygenation

BACKGROUND

Venoarterial extracorporeal membrane oxygenation (V-A ECMO) improves perfusion and oxygenation in patients with cardiogenic shock. However, it can also result in supranormal oxygen exposure. Recent evidence suggests hyperoxia may be harmful, particularly in critically ill patients. The aim of this study was to describe oxygen exposure in patients receiving V-A ECMO after acute myocardial infarction and to investigate the association between hyperoxia and in-hospital mortality.

METHODS AND DESIGN

We conducted a retrospective, cohort study of consecutive patients receiving V-A ECMO at a single tertiary level ECMO centre. We compared the mean and peak arterial oxygen tensions over the first 72 h after V-A ECMO initiation (n = 30) with those from a convenience sample of patients treated with an intra-aortic balloon pump (IABP) (n = 30) for cardiogenic shock.

RESULTS

Sixty patients admitted between January 2012 and March 2018 were included in the study. Patients on V-A ECMO had significantly higher arterial oxygen tensions during the first three days than those with an IABP, at 0-24 h; V-A ECMO: 286.51 mmHg (135.76) vs IABP: 103.48 mmHg (15.22), p < 0.01.Thirteen of 30 (44.8%) patients in the V-A ECMO cohort manifested extreme hyperoxia (PaO₂ ≥300 mmHg) in the first 24 hrs, compared with none in the IABP population. Within the V-A ECMO group, there was no significant association between extreme hyperoxia and in-hospital mortality (P = 0.19), duration of mechanical ventilation (P = 0.63), or troponin levels (P = 0.16) in the first 24 hrs.

CONCLUSION

Severe hyperoxia is common in patients receiving V-A ECMO after acute myocardial infarction, and this continues for at least 72 h. We found no association between extreme hyperoxia and clinical outcomes.

A survey of extracorporeal membrane oxygenation practice in 23 Australian adult intensive care units

In Australia, extracorporeal membrane oxygenation (ECMO) is one of the most expensive diagnosis-related groups, costing $305 463 per complex admission to the intensive care unit(ICU). Mortality in this group of patients is high, about 43% for respiratory failure and 68% for cardiac failure. ECMO is associated with significant risk to the patient and requires specialist training andexpertise. Variation in clinical practice for patients supported with ECMO may compromise patient care and outcomes.

Predictors of mortality after extracorporeal cardiopulmonary resuscitation

OBJECTIVE

Extracorporeal membrane oxygenation (ECMO) is a promising adjunct to cardiopulmonary resuscitation (CPR) in refractory cardiac arrest (CA). Factors associated with outcome are incompletely characterised. The aim of our study was to identify pre-ECMO factors associated with in-hospital mortality after extracorporeal CPR (ECPR).

DESIGN

Retrospective analysis of a prospective cohort of patients.

SETTING

Academic quaternary referral hospital.

PARTICIPANTS

All patients who underwent ECPR from January 2012 through April 2017.

INTERVENTIONS

A retrospective chart review was performed for CPR and ECMO. A multivariable logistic regression was performed to identify factors associated with mortality after ECPR.

MAIN OUTCOME MEASURES

Primary outcome was in-hospital mortality. Secondary outcomes included survival with favourable neurologic outcome, days on ECMO, and intensive care unit (ICU) length of stay.

RESULTS

During the study period, 75 patients received ECPR. Median age was 59 years, 81% were male, 51% had out-of-hospital CA, and 57% had an initial shockable rhythm. Median time from arrest to ECMO was 91 minutes (IQR, 56-129) for non-survivors and 51 minutes (IQR, 37-84) for survivors (P =0.02). Twenty-six patients (39%) were successfully separated from ECMO, with 31% surviving to hospital discharge and 29% with a cerebral performance category score of 1 or 2. In multivariable analysis, significant predictors of in-hospital mortality were ongoing CPR at the time of ECMO initiation (P < 0.01) and arrest to ECMO cannulation time (P =0.02).

CONCLUSION

Following ECPR, the factors most strongly associated with mortality were ongoing CPR at the time of ECMO initiation and arrest to ECMO cannulation time. Interventions aimed at reducing time to ECMO initiation may lead to improved outcomes.

Cannulation technique: femoro-femoral

The cannulation technique used during veno-venous extracorporeal membrane oxygenation (VV ECMO) insertion can have a major impact on a patients' overall outcome. We have developed a technique that aims to combine speed and effectiveness, with minimal risk. The steps include: (I) percutaneous cannulation using the Seldinger technique; (II) ultrasound guided access and positioning of cannulas; (III) femoro-femoral circuit configuration with a later option of high flow; (IV) a no skin cut serial dilation technique; (V) non-suturing securing of cannulas and (VI) a non-surgical manual pressure technique of explantation. The following is a discussion around these techniques and their various advantages and disadvantages.

Recovery, Risks, and Adverse Health Outcomes in Year 1 After Extracorporeal Membrane Oxygenation

BACKGROUND

Cross-sectional studies suggest that patients treated with extracorporeal membrane oxygenation (ECMO) have adverse health outcomes and high risk for mental health problems after discharge.

OBJECTIVES

To describe the recovery of discharged patients during the first year after ECMO.

METHODS

In a prospective cohort study, data were collected 3, 6, and 12 months after discontinuation of ECMO and discharge. Postal surveys included the 36-Item Short Form Health Survey, the EuroQol-5-Dimensions-5-Levels health questionnaire, the Hospital Anxiety and Depression Scale, and the Impact of Event Scale-Revised. Telephone interviews were used to track adverse physical outcomes. The Telephone Interview for Cognitive Status questionnaire was administered at the end of each call.

RESULTS

Patients in the study experienced more physical than mental adverse health outcomes, and the risk for mental problems was 2 or 3 times the rate expected. Adverse physical outcomes were common. One-quarter of patients remained significantly restricted; some had severe neurological impairments of the lower extremities. On cognitive tests, about half scored inconclusive or mildly impaired. Patients were often admitted to the hospital.

CONCLUSIONS

Physical health was more severely impaired than was mental health, and both types improved over time. The EuroQol-5-Dimensions-5-Levels instrument was useful for detecting neurological problems of the lower extremities early and may qualify as a core outcome measure for patients treated with ECMO.

Predictive factors of bleeding events in adults undergoing extracorporeal membrane oxygenation

Background

Bleeding is the most frequent complication associated with extracorporeal membrane oxygenation (ECMO) support in critically ill patients. Nonetheless, risk factors for bleeding have been poorly described especially those associated with coagulation anomalies and anticoagulant therapy during ECMO support. The aim of this study is to describe bleeding complications in critically ill patients undergoing ECMO and to identify risk factors for bleeding events.

Methods

We retrospectively analysed ICU charts of adults who received either veno-venous (VV) or veno-arterial (VA) ECMO support in two participating ICUs between 2010 and 2013. Characteristics of patients with and without bleeding complications, as per the Extracorporeal Life Support Organisation (ELSO) definition, were compared, and the impact of bleeding complications on patient outcomes was assessed using survival analysis. Variables that were independently associated with bleeding, including daily clinical and biological variables during ECMO courses, were modelled.

Results

Of the 149 ECMO episodes (111 VA ECMO and 38 VV ECMO) performed in 147 adults, 89 episodes (60 %) were complicated by at least one bleeding event. The most common bleeding sources were: ECMO cannula (37 %), haemothorax or cardiac tamponade (17 %) and ear–nose and throat (16 %). Intra-cranial haemorrhage occurred in five (2.2 %) patients. Bleeding complications were independently associated with worse survival [adjusted hazard ratio (HR) 2.17, 95 % confidence interval (CI) 1.07–4.41, P = 0.03]. Higher activated partial thromboplastin time (aPTT) [adjusted odds ratio (OR) 3.00, 95 % CI 1.64–5.47, P < 0.01], APACHE III score [adjusted OR 1.01, 95 % CI 1.01–1.02, P = 0.01] and ECMO following surgery [adjusted OR 3.04, 95 % CI 1.62–5.69, P < 0.01] were independently associated with greater risk of bleeding occurrence. A similar association between bleeding and higher aPTT was found when non-post-surgical VA ECMO was considered separately.

Conclusions

Bleeding events based on the ELSO bleeding definition occurred in more than 60 % of ECMO episodes and were associated with hospital mortality. We identified higher aPTT prior bleeding as an independent risk factor for bleeding event, suggesting that better control of the aPTT (through a better control of either coagulopathy or anticoagulation) may improve patients’ outcome.

A qualitative exploration of acute care and psychological distress experiences of ECMO survivors

OBJECTIVES

To explore the acute care experience of extracorporeal membrane oxygenation (ECMO) patients.

BACKGROUND

ECMO is used in life-threatening scenarios of acute lung or heart failure. The patient's experience with ECMO treatment and the psychological distress are unknown.

METHODS

Qualitative analysis of semi-structured interviews with ECMO survivors 12 months after discharge were conducted and thematically analyzed.

RESULTS

Ten participants treated with ECMO for life-threatening acute heart or lung failure were interviewed. Six themes that captured the ICU experience of ECMO patients were identified including; dealing with crisis, critical care, memory, role of significant others and existence today and tomorrow. Deconditioning was the most frequently reported experience. Patchy factual memories contrasted with detailed delirious memories and paranoid ideations.

CONCLUSION

Patients treated with ECMO experienced deconditioning, perceived threats of serious injury or death and delusional episodes with recalls of psychological distress.

Refractory cardiac arrest treated with mechanical CPR, hypothermia, ECMO and early reperfusion (the CHEER trial)

INTRODUCTION

Many patients who suffer cardiac arrest do not respond to standard cardiopulmonary resuscitation. There is growing interest in utilizing veno-arterial extracorporeal membrane oxygenation assisted cardiopulmonary resuscitation (E-CPR) in the management of refractory cardiac arrest. We describe our preliminary experiences in establishing an E-CPR program for refractory cardiac arrest in Melbourne, Australia.

METHODS

The CHEER trial (mechanical CPR, Hypothermia, ECMO and Early Reperfusion) is a single center, prospective, observational study conducted at The Alfred Hospital. The CHEER protocol was developed for selected patients with refractory in-hospital and out-of-hospital cardiac arrest and involves mechanical CPR, rapid intravenous administration of 30 mL/kg of ice-cold saline to induce intra-arrest therapeutic hypothermia, percutaneous cannulation of the femoral artery and vein by two critical care physicians and commencement of veno-arterial ECMO. Subsequently, patients with suspected coronary artery occlusion are transferred to the cardiac catheterization laboratory for coronary angiography. Therapeutic hypothermia (33 °C) is maintained for 24h in the intensive care unit.

RESULTS

There were 26 patients eligible for the CHEER protocol (11 with OHCA, 15 with IHCA). The median age was 52 (IQR 38-60) years. ECMO was established in 24 (92%), with a median time from collapse until initiation of ECMO of 56 (IQR 40-85) min. Percutaneous coronary intervention was performed on 11 (42%) and pulmonary embolectomy on 1 patient. Return of spontaneous circulation was achieved in 25 (96%) patients. Median duration of ECMO support was 2 (IQR 1-5) days, with 13/24 (54%) of patients successfully weaned from ECMO support. Survival to hospital discharge with full neurological recovery (CPC score 1) occurred in 14/26 (54%) patients.

CONCLUSIONS

A protocol including E-CPR instituted by critical care physicians for refractory cardiac arrest which includes mechanical CPR, peri-arrest therapeutic hypothermia and ECMO is feasible and associated with a relatively high survival rate.