Clinical significance of echocardiography in patients supported by venous-venous extracorporeal membrane oxygenation

Assessing Right Ventricle Over Time in Patients on Veno-Venous Extracorporeal Membrane Oxygenation: Insights From Serial Echocardiography

Extracorporeal membrane oxygenation (ECMO) is often used in acute respiratory distress syndrome (ARDS) with refractory hypoxemia. There is limited literature highlighting the development of right ventricular (RV) failure while on ECMO. We conducted a retrospective multicenter observational study including 70 patients who were placed on veno-venous (VV)-ECMO for respiratory failure at Mayo Clinic, Jacksonville, and Mayo Clinic, Rochester, between January 2018 and June 2022 and had at least two post-ECMO transthoracic echoes. The primary outcomes were the incidence and progression of RV dysfunction and dilatation. The secondary outcome was in-patient mortality. Among 70 patients in our cohort, 60.6% had a normal RV function at the time of ECMO placement, whereas only 42% had a normal RV function at the second post-ECMO echo. On multinomial regression, a moderate decrease in RV function was associated with ECMO flow (odds ratio [OR] = 2.32, p = 0.001) and ECMO duration (OR = 1.01, p = 0.01). A moderately dilated RV size was also associated with ECMO flow (OR = 2.62, p < 0.001) and ECMO duration (OR = 1.02, p = 0.02). An increasing degree of RV dysfunction was associated with worse outcomes. Our study showed that the increasing duration and flow of VV-ECMO correlated with progressive RV dilatation and dysfunction, which were associated with poor survival.

Veno-venous extracorporeal membrane oxygenation (VV ECMO) cannula malposition identified with point-of-care ultrasound

BACKGROUND

Point-of-care ultrasound (POCUS) has become a mainstay in the evaluation of critically ill patients in the intensive care unit (ICU). ECMO patients are susceptible to complications during prolonged ICU stay, including cannula malposition, which has deleterious consequences. Although the literature surrounding utility of ultrasound on ECMO patients is expansive, direct comparison between radiographic imaging versus ultrasound for identification of cannula malposition is lacking.

CASE PRESENTATION

The authors identified four patients with cannula malposition discovered through POCUS that was missed on routine radiographic imaging. Identification and correction of malposition changed their ECMO course.

CONCLUSION

This case series is the first in literature demonstrating that ultrasound may be superior to radiographic images for ECMO cannula malposition. Further investigation into this subject is warranted.

Head-to-toe bedside ultrasound for adult patients on extracorporeal membrane oxygenation

Bedside ultrasound represents a well-suited diagnostic and monitoring tool for patients on extracorporeal membrane oxygenation (ECMO) who may be too unstable for transport to other hospital areas for diagnostic tests. The role of ultrasound, however, starts even before ECMO initiation. Every patient considered for ECMO should have a thorough ultrasonographic assessment of cardiac and valvular function, as well as vascular anatomy without delaying ECMO cannulation. The role of pre-ECMO ultrasound is to confirm the indication for ECMO, identify clinical situations for which ECMO is not indicated, rule out contraindications, and inform the choice of ECMO configuration. During ECMO cannulation, the use of vascular and cardiac ultrasound reduces the risk of complications and ensures adequate cannula positioning. Ultrasound remains key for monitoring during ECMO support and troubleshooting ECMO complications. For instance, ultrasound is helpful in the assessment of drainage insufficiency, hemodynamic instability, biventricular function, persistent hypoxemia, and recirculation on venovenous (VV) ECMO. Lung ultrasound can be used to monitor signs of recovery on VV ECMO. Brain ultrasound provides valuable diagnostic and prognostic information on ECMO. Echocardiography is essential in the assessment of readiness for liberation from venoarterial (VA) ECMO. Lastly, post decannulation ultrasound mainly aims at identifying post decannulation thrombosis and vascular complications. This review will cover the role of head-to-toe ultrasound for the management of adult ECMO patients from decision to initiate ECMO to the post decannulation phase.

Experience With the Crescent• Right Atrial Jugular Dual Lumen Catheter for Pediatric Venovenous Extracorporeal Membrane Oxygenation: A Case Series

The Crescent dual lumen right atrial (RA) cannula has recently been introduced for the support of pediatric patients in need of venovenous extracorporeal membrane oxygenation (VV ECMO) support. We present the first pediatric case series illustrating utility of the Crescent RA cannula in the pediatric patient population at a single institution over a 10 month period. From December 2021 to August 2022, six pediatric patients were adequately supported on seven VV ECMO runs at our institution with the Crescent RA cannula. ECMO cannulation, circuit design, anticoagulation management, ECMO circuit pressures, flow rates, and recirculation were similar to our standard of care for VV ECMO. The Crescent RA cannula can be used safely and effectively to provide adequate support for pediatric patients requiring VV ECMO.

Successful treatment of severe ARDS caused by accidental inhalation of nitric acid fumes with veno-venous ECMO: A case report and literature review

RATIONALE

The treatment of severe acute respiratory distress syndrome caused by accidental inhalation of nitric acid fumes is challenging. Few successful cases have been reported in literature. Owing to the development of extracorporeal life support, extracorporeal membrane oxygenation (ECMO) may play an important role in treatment.

PATIENT CONCERNS

A 40-year-old man was accidentally exposed to nitric acid fumes for 10 minutes in a factory. Mild throat irritation and dyspnea occurred 3.5 hours after exposure. Severe dyspnea recurred approximately two hours later. Chest computed tomography revealed bilateral interstitial edema. Tracheal intubation and mechanical ventilation were provided when the non-invasive ventilator failed to support the patient. However, his vital signs, respiratory function, and circulation were aggravated.

DIAGNOSIS

Aspiration pneumonia (inhalation of nitric acid fumes), acute respiratory distress syndrome, and hypertension.

INTERVENTIONS

Veno-venous ECMO (VV-ECMO) was started 6 hours after exposure at the intensive care unit. During VV-ECMO, hypoxia improved. However, chest radiography revealed aggravated pulmonary edema. Prone positioning under ultrasound monitoring and high-dose methylprednisolone were administered on the first day. Nebulization and fiberoptic bronchoscopy for airway management were performed on the second day after the exposure. Pulmonary secretions were significantly reduced 48 hours later.

OUTCOMES

The patient was weaned off V-V ECMO after 6 days, achieved the standard of extubation after 9 days, and was discharged without serious pulmonary or infectious complications after 12 days of hospitalization. Three weeks after discharge, the patient's lung function showed a slight decline in the diffusion function. Two months after discharge, the patient's lung function returned to normal.

LESSON

Early ECMO combined with prone positioning and visualized management through ultrasonography can better improve the prognoses of patients and promote lung function recovery.

Echocardiography for extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) provides advanced cardiopulmonary life support for patients in cardiac and/or respiratory failure. Echocardiography provides essential diagnostic and anatomic information prior to ECMO initiation, allows for safe and efficient ECMO cannula positioning, guides optimization of flow, provides a modality for rapid troubleshooting and patient evaluation, and facilitates decision-making for eventual weaning of ECMO support. Currently, guidelines for echocardiographic assessment in this clinical context are lacking. In this review, we provide an overview of echocardiographic considerations for advanced imagers involved in the care of these complex patients. We focus predominately on new cannulas and complex cannulation techniques, including a special focus on double lumen cannulas and a section discussing indirect left ventricular venting. Echocardiography is tremendously valuable in providing optimal care in these challenging clinical situations. It is imperative for imaging physicians to understand the pertinent anatomic considerations, the often complicated physiological and hemodynamic context, and the limitations of the imaging modality.

Severity of acute respiratory distress syndrome and echocardiographic findings in clinical practice-an echocardiographic pilot study

BACKGROUNDS

The still high poor outcome of ARDS may be more consequence of circulatory failure than hypoxemia per se. For patients with circulatory failure and ARDS, hemodynamic instability is directly related to ARDS following pulmonary circulation dysfunction and its consequence - right ventricular (RV) dysfunction.

OBJECTIVES

We hypothesize that in the era of protective ventilation, echocardiographic abnormalities did not parallel ARDS severity, defined by the degree of hypoxemia.

METHODS

We included 63 consecutively identified mechanically ventilated ARDS patients (1st January 2015 to 31th December 2016). All had echocardiography performed routinely within the first 12 h after ICU admission.

RESULTS

The analysis included 110 exams. Twenty-eight patients had severe ARDS (28/63, 44.4%), 27 had moderate ARDS (27/63, 42.1%) and 8 mild ARDS (8/63, 12.7%).There was no difference in echocardiographic findings between mild-moderate and severe ARDS. At Pearson's linear regression analysis, TAPSE was directly correlated with LVEF (r = 0.22, p = 0.021) and inversely with sPAP (r = -0.37, p < 0.001). Systolic pulmonary arterial pressure (sPAP) showed a direct correlation with pCO₂ (r = 0.30, p = 0.002) and an inverse one with pH (r = -0.35, p < 0.001) and TAPSE (r =-0.35, p < 0.001).

CONCLUSIONS

Among patients with ARDS, the severity of disease (as indicated by pO2) does not translate into specific cardiac abnormalities, detected by echocardiography. However, RV function (as indicated by TAPSE) is inversely related to pCO₂ and to sPAP (which therefore may be underestimated in presence ofRV dysfunction). Our data strongly suggest that in mechanically ventilated ARDS, the interpretation of echo findings should consider also pCO₂ values.

The Role of Echocardiography in Neonates and Pediatric Patients on Extracorporeal Membrane Oxygenation

Indications for extracorporeal membrane oxygenation (ECMO) and extracorporeal cardiopulmonary resuscitation (ECPR) are expanding, and echocardiography is a tool of utmost importance to assess safety, effectiveness and readiness for circuit initiation and separation. Echocardiography is key to anticipating complications and improving outcomes. Understanding the patient's as well as the ECMO circuit's anatomy and physiology is crucial prior to any ECMO echocardiographic evaluation. It is also vital to acknowledge that the utility of echocardiography in ECMO patients is not limited to the evaluation of cardiac function, and that clinical decisions should not be made exclusively upon echocardiographic findings. Though echocardiography has specific indications and applications, it also has limitations, characterized as: prior to and during cannulation, throughout the ECMO run, upon separation and after separation from the circuit. The use of specific and consistent echocardiographic protocols for patients on ECMO is recommended.

Monitoring during extracorporeal membrane oxygenation

PURPOSE OF REVIEW

An increasing number of patients are placed on extracorporeal membrane oxygenation (ECMO) for respiratory or cardiac failure. Sound understanding of physiology and configuration of ECMO is essential for proper management. This review covers different monitoring parameters and tools for patients supported with different types of ECMO.

RECENT FINDINGS

Emphasis is placed on monitoring saturations at different sites depending on type of ECMO support. The main monitoring tools detailed in this review are echocardiography and pulmonary artery catheters.

SUMMARY

The review will help physicians better assess adequate ECMO support by using the appropriate parameters for each type of configuration.

Perioperative Management of the Adult Patient on Venovenous Extracorporeal Membrane Oxygenation Requiring Noncardiac Surgery

The use of venovenous extracorporeal membrane oxygenation is increasing worldwide. These patients often require noncardiac surgery. In the perioperative period, preoperative assessment, patient transport, choice of anesthetic type, drug dosing, patient monitoring, and intraoperative and postoperative management of common patient problems will be impacted. Furthermore, common monitoring techniques will have unique limitations. Importantly, patients on venovenous extracorporeal membrane oxygenation remain subject to hypoxemia, hypercarbia, and acidemia in the perioperative setting despite extracorporeal support. Treatments of these conditions often require both manipulation of extracorporeal membrane oxygenation settings and physiologic interventions. Perioperative management of anticoagulation, as well as thresholds to transfuse blood products, remain highly controversial and must take into account the specific procedure, extracorporeal membrane oxygenation circuit function, and patient comorbidities. We will review the physiologic management of the patient requiring surgery while on venovenous extracorporeal membrane oxygenation.

A novel risk score for severe ARDS patients undergoing ECMO after retrieval from peripheral hospitals

BACKGROUND

Extracorporeal Membrane Oxygenation in severe ARDS unresponsive to conventional protective ventilation is associated with elevated costs, resource and complications, and appropriate risk stratification of candidate patients could be useful to recognize those more likely to benefit from ECMO. We aimed to derive a new outcome prediction score for patients retrieved by our ECMO team from peripheral centers, including systematic echocardiographic evaluation before ECMO start.

METHODS

Sixty-nine consecutive patients with refractory ARDS requiring ECMO transferred from peripheral centers to our ICU (a tertiary ECMO referral center), from 1 October 2009 to 31 December 2015, were assessed.

RESULTS

All patients were transported on ECMO (distance, median 77, range 4-456 km) The mortality rate was 41% (28/69). Our new risk score included age ≥ 42 years, BMI < 31 kg/m² , RV dilatation, and pH < 7.35. The proposed cut off (Youden's index method) of nine had a sensitivity of 96% and a specificity of 30% (AUC-ROC: 0.85, 95% CI: 0.76-0.94, P < 0.001). When assessing the discriminatory ability of our risk score in the population of local patients, survivors had a mean value of 15.4 ± 8.6, whereas non-survivors showed a mean value of 20.1 ± 7.4 (P < 0.001).

CONCLUSIONS

Our new risk score shows good discriminatory ability both in patients retrieved from peripheral centers and in those implanted at our center. This score includes variables easily available at bedside, and, for the first time, a pathophysiologic element, RV dilatation.

Lactate and Echocardiography Before Veno-Venous Extracorporeal Membrane Oxygenation Support

BACKGROUND

Lactate has been recognised as a prognostic factor in several critical conditions. Veno-Venous Extracorporeal Membrane Oxygenation (VV-ECMO) is a well-established therapy in patients with Acute Respiratory Disease Syndrome (ARDS) unresponsive to conventional therapy and echocardiography pre ECMO initiation has been recently reported to help in risk stratifying these patients.

METHODS

We assessed whether the detection of hyperlactataemia could be associated with the presence of left ventricle (LV) or right ventricle (RV) dysfunction in 121 consecutive patients with refractory ARDS.

RESULTS

The mortality rate was 42.9% (52/121). Higher dosages of norepinephrine and dobutamine were administered to non survivors (p=0.023 and p=0.047, respectively) who showed significantly higher levels of lactate (p=0.002). At echocardiography, non survivors showed higher values of systolic pulmonary artery pressure (sPAP) (p=0.05) and a higher incidence of RV dysfunction (as indicated by lower Tricuspid Annular Plane Excursion (TAPSE)) and RV dilatation (p=0.001). At multivariate logistic regression analysis, the following variables were independent predictors of death: body mass index (BMI) (OR: 0.914, 95%CI 0.857-0.975, p=0.006), RV dilatation (OR: 0.239, 95%CI 0.101-0.561, p=0.001) and lactate (OR: 1.292, 95%CI 1.015-1.645, p=0.038). Lactate values were directly correlated with the simplified acute physiology score (SAPS) II (r=0.38, p<0.001), while they showed an indirect correlation with left ventricular ejection fraction (LVEF) (r=-0.24, p=0.009) and TAPSE (r=-0.21, p=0.024).

CONCLUSIONS

In refractory ARDS, hyperlactataemia before VVV-ECMO identified a subset of patients at higher risk of death, being an independent predictor of in-Intensive Care Unit (ICU) mortality. Lactate values are mainly related to disease severity (as indicated by SAPS II) and haemodynamic impairment (as inferred by LVEF) and RV failure, as (indicated by TAPSE).

Pulmonary vascular dysfunction in refractory acute respiratory distress syndrome before veno-venous extracorporeal membrane oxygenation

BACKGROUND

Pulmonary vascular dysfunction has been described in patients with acute respiratory distress syndrome (ARDS). Veno-venous extracorporeal membrane oxygenation (VV-ECMO) is a well-established treatment for these patients. We hypothesized that severe pulmonary vascular dysfunction and cor pulmonale identified by echocardiography before cannulation in these patients were associated with worse survival.

METHODS

Echocardiography was used to identify pulmonary hypertension in 21 patients with refractory ARDS just before ECMO implantation. Survival was compared for those with and without cor pulmonale.

RESULTS

In our series, the overall mortality rate was 57.1% (12/21). Echocardiographic exams were transthoracic in 5 patients (23.8%), transesophageal in 4 patients (19%), and both (transthoracic and transesophageal) in the remaining 12 patients (57.1%). In our series, six patients (28.5%) showed LV dysfunction. Acute cor pulmonale was detectable in 2 patients (9.5%), while the remaining 19 patients showed moderate pulmonary dysfunction. Survivors had a higher pre-cannulation LV ejection fraction (EF) (P = 0.02) and tricuspid annular plane excursion (P = 0.04), and lower peak systolic pulmonary artery pressures (P = 0.02).

CONCLUSIONS

In patients with refractory ARDS immediately before ECMO implantation, the prevalence of acute cor pulmonale is low (9.5%). Survival is associated with higher LVEF and lower systolic pulmonary arterial pressure. These findings support the idea that echocardiographic assessment of pulmonary artery pressure in patients with refractory ARDS before VV-ECMO implantation may have value for risk-stratification.

Serial measurements of troponin and echocardiography in patients with moderate-to-severe acute respiratory distress syndrome

PURPOSE

To assess the clinical significance of serial troponin I levels (measured in the first 72 hours from admission) in 42 consecutive patients with moderate-to-severe acute respiratory distress syndrome (ARDS). Echocardiography and electrocardiogram testings were serially performed in the time window.

MATERIALS AND METHODS

Troponin I was measured every 12 hours in the first 72 hours from intensive care unit (ICU) admission. Echocardiography and electrocardiogram testings were serially performed in the same time window to clinically interpret Tn I levels.

RESULTS

Patients with admission positive Tn I (38.1%) showed higher values of systolic pulmonary hypertension (P = .013) associated with significantly lower values of tricuspid annular plane excursion (P = .011). Twenty-five patients (25/42, 59.5%) exhibited positive peak Tn I and at second echocardiographic assessment exhibited significant lower tricuspid annular plane excursion values (P = .005). At stepwise regression analysis the following variables were an independent predictor for in-ICU mortality: Pco2 (OR 1.08, 95% CI 1.011-1.161, P = .023), systolic pulmonary arterial hypertension (OR 0.83, 95% CI 0.701-0.977, P = .002), log peak Tn I (OR 3.56, 95% CI 1.045-12.132, P = .042).

CONCLUSIONS

In moderate-to-severe ARDS, serial troponin I assessment together with echocardiography evaluation helped to identify a subgroup at higher risk for in-ICU death. Moreover, troponin release can be related to right ventricular dysfunction, thus highlighting the clinical role of echocardiography in ARDS patients.

The potential role and limitations of echocardiography in acute respiratory distress syndrome

Bedside use of Doppler echocardiography is being featured as a promising, clinically useful tool in assessing the pulmonary circulation in patients with acute respiratory distress syndrome (ARDS). The present review is aimed at summarizing the available evidence obtained with echocardiography on right ventricle (RV) function and pulmonary circulation in ARDS and to highlight the potential of this technique in clinical practice (only articles in English language were considered). According to the available evidence on echocardiographic findings, the following conclusions can be drawn: (a) echocardiography (transthoracic and transesophageal) has a growing role in the management ARDS patients mainly because of the strict interactions between the lung (and ventilation) and the RV and pulmonary circulation; (b) there may be a continuum of alterations in RV size and function and pulmonary circulation which may end in the development of acute cor pulmonale, probably paralleling ARDS disease severity; and (c) the detection of acute cor pulmonale should prompt intensivists to tailor their ventilatory strategy to the individual patient depending on the echocardiography findings. Bearing in mind the clinical role and growing importance of echocardiography in ARDS and the available evidence on this topic, we present a flow chart including the parameters to be measured and the timing of echo exams in ARDS patients. Despite the important progress that echocardiography has gained in the evaluation of patients with ARDS, several open questions remain and echocardiography still appears to be underused in these patients. A more systematic use of echocardiography (mainly through shared protocols) in ARDS could help intensivists to tailor the optimal treatment in individual patients as well as highlighting the limits and potential of this methodology in patients with ALI.

Echocardiography for adult patients supported with extracorporeal membrane oxygenation

Venoarterial (VA) and venovenous (VV) extracorporeal membrane oxygenation (ECMO) support is increasingly being used in recent years in the adult population. Owing to the underlying disease precipitating severe respiratory or cardiac failure, echocardiography plays an important role in the management of these patients. Nevertheless, there are currently no guidelines on the use of echocardiography in the setting of ECMO support. This review describes the current state of application of echocardiography for patients supported with both VA and VV ECMO.