Incidence of Venous Thromboembolism in Adults Receiving Extracorporeal Membrane Oxygenation: A Systematic Review

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.

Early Blood Clot Detection Using Forward Scattering Light Measurements Is Not Superior to Delta Pressure Measurements

The occurrence of thrombus formation within an extracorporeal membrane oxygenator is a common complication during extracorporeal membrane oxygenation therapy and can rapidly result in a life-threatening situation due to arterial thromboembolism, causing stroke, pulmonary embolism, and limb ischemia in the patient. The standard clinical practice is to monitor the pressure at the inlet and outlet of oxygenators, indicating fulminant, obstructive clot formation indicated by an increasing pressure difference (ΔP). However, smaller blood clots at early stages are not detectable. Therefore, there is an unmet need for sensors that can detect blood clots at an early stage to minimize the associated thromboembolic risks for patients. This study aimed to evaluate if forward scattered light (FSL) measurements can be used for early blood clot detection and if it is superior to the current clinical gold standard (pressure measurements). A miniaturized in vitro test circuit, including a custom-made test chamber, was used. Heparinized human whole blood was circulated through the test circuit until clot formation occurred. Four LEDs and four photodiodes were placed along the sidewall of the test chamber in different positions for FSL measurements. The pressure monitor was connected to the inlet and the outlet to detect changes in ΔP across the test chamber. Despite several modifications in the LED positions on the test chamber, the FSL measurements could not reliably detect a blood clot within the in vitro test circuit, although the pressure measurements used as the current clinical gold standard detected fulminant clot formation in 11 independent experiments.

Nosocomial infections in adult patients receiving extracorporeal membrane oxygenation in China: A retrospective cohort study

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) has been increasingly used in China, but nosocomial infections (NI) in patients receiving ECMO remain poorly characterized. Thus, this study aimed to investigate the incidence rate, causative was pathogens, and risk factors of NIs in ECMO patients.

METHODS

A retrospective cohort study of patients receiving ECMO between January 2015 and October 2021 was conducted in a tertiary hospital. General demographics and clinical data of the included patients were collected from the electronic medical record system and the real-time NI surveillance system.

RESULTS

A total of 86 infected patients with 110 episodes of NIs were identified in 196 patients receiving ECMO. The incidence of NI was 59.2/1000 ECMO days. The median time for the first NI in ECMO patients was 5 days (interquartile range: 2-8 days). Hospital-acquired pneumonia and bloodstream infections were common types of NIs in ECMO patients, and the main pathogens were gram-negative bacteria. Pre-ECMO invasive mechanical ventilation (OR = 2.40, 95% CI:1.12-5.15) and prolonged duration of ECMO (OR = 1.26, 95% CI:1.15-1.39) were risk factors for NIs during ECMO support.

DISCUSSION

This study identified the main infection sites and pathogens of NIs in ECMO patients. Although NIs may not affect successful ECMO weaning, additional measures should be implemented to reduce the incidence of NI during ECMO support.

Results from 237 extracorporeal membrane oxygenation runs with drowned patients: a nationwide retrospective study

BACKGROUND

Drowning is one of the leading causes of death worldwide and presents with a wide range of symptoms, from simple coughing to cardiac or pulmonary failure. In severe cases, extracorporeal membrane oxygenation (ECMO) should be considered as a rescue therapy. Therefore, we sought to analyse ECMO usage, outcomes and predictive factors in drowned patients.

METHODS

The Federal Statistical Office of Germany provided the study data. The patients included experienced drowning (ICD T75.1) and ECMO (OPS 8-852.0, 8-852.3) between 2007 and 2020. All age groups were included. Mortality was calculated for the total population and for ECMO patients. A multiple logistic regression model for ECMO patients was applied to account for predefined patient characteristics and complications.

RESULTS

Of 12,354 patients who were hospitalised due to drowning, 237 patients (1.9%) received ECMO. Hospital mortality was 14.1% (n = 1741) overall and 74.7% (n = 177) for ECMO patients. In-hospital mortality was positively associated with cardiopulmonary resuscitation (CPR) before admission (odds ratio [OR] 4.49, 1.31-15.39) and in-hospital CPR (OR 6.28, 2.76-14.31). Stroke (OR 0.14, 0.02-0.96) and drug abuse (OR 0.05, 0.01-0.45) were negatively associated with in-hospital mortality. Neither the ECMO mode nor the patient's age and sex had statistically significant effects on survival.

CONCLUSION

This study indicates that survival in drowned patients who receive ECMO is lower than previously reported. The proportion of paediatric patients was also smaller than expected. As the effects of different ECMO modes on mortality remain unclear, the need for further study remains great.

Extracorporeal Membrane Oxygenation in Acute Respiratory Failure

Venovenous (VV) extracorporeal membrane oxygenation (ECMO) is a form of mechanical life support that provides full respiratory bypass in patients with severe respiratory failure as a bridge to recovery or lung transplantation. The use of ECMO for respiratory failure and capable centers offering ECMO has expanded over the years, increasing its availability. As VV-ECMO provides an artificial mechanism for oxygenation and decarboxylation of native blood, it allows for an environment in which safer mechanical ventilatory care may be provided, allowing for treatment and resolution of underlying respiratory pathologies. Landmark clinical trials have provided a framework for better understanding patient selection criteria, resource utilization, and outcomes associated with ECMO when applied in settings of refractory respiratory failure. Maintaining close vigilance and management of complications during ECMO as well as identifying strategies post-ECMO (e.g., recovery, transplantation, etc.), are critical to successful ECMO support. In this review, we examine considerations for candidate selection for VV-ECMO, review the evidence of utilizing VV-ECMO in respiratory failure, and provide practical considerations for managing respiratory ECMO patients, including complication identification and management, as well as assessing for the ability to separate from ECMO support and the procedures for decannulation.