10-year HK study: How has ECMO utilization evolved in public hospitals?

A 10-year territory-wide study has shown a 9.5-fold increase in utilization of extracorporeal membrane oxygenation (ECMO) among adult patients admitted to intensive care units (ICUs) of public hospitals in Hong Kong, especially older patients and patients with more severe disease or comorbidities.

The study also revealed substantial resource requirement for ECMO use. To maintain the quality of care in ECMO, the researchers suggested service consolidation, along with appropriate resource allocation and training. [Hong Kong Med J2023;doi:10.12809/hkmj2210025]

ECMO serves as life support for assisting heart and lung functions in patients with circulatory or respiratory failure. Following the formalization of ECMO services in Hong Kong, the number of ECMO centres had increased from three in 2010 to five in 2015, and further to seven in 2019. Meanwhile, the number of ECMO consoles rose from three in 2010 to nine in 2015 and, subsequently, to 11 in 2019.

To understand the status of Hong Kong’s ECMO services, the researchers analyzed data of 911 ICU-admitted patients (male, 64 percent; median age at admission, 54 years; median Charlson Comorbidity Index [CCI], 1) receiving ECMO (venoarterial-ECMO [VA-ECMO], 32.6 percent; venovenous-ECMO, [VV-ECMO], 49.4 percent; extracorporeal cardiopulmonary resuscitation [ECPR], 18.0 percent) between 2010 and 2019. Of these patients, identified from an administrative ECMO registry, 97.6 percent had complete data on Acute Physiology and Chronic Health Evaluation IV (APACHE IV; median score, 100).

Over the study period, ECMO use steadily increased from 18 patients in 2010 to 171 patients in 2019. Notably, the annual number of patients aged ≥65 years increased from 0 to 47 (0 vs 27.5 percent; p_trend=0.001) in the same period. The median CCI score also increased from 1 to 2 (p_trend<0.001), while the median APACHE IV score rosed from 90 to 105 (p_trend=0.003).

The use of ECMO necessitated substantial resources. In the study cohort, 51.5 percent of patients initiated ECMO (VV-ECMO, 52.7 percent; VA-ECMO, 29.2 percent; ECPR, 18.1 percent) outside regular hours (9 am–5 pm), and 24.4 percent required interhospital transfer from non-ECMO centres (ICUs in other hospitals, 77.9 percent; non-ICU settings, 22.1 percent). Within 7 days of tertiary transfer, 24.3 percent of patients (n=54) underwent major operations. Of these surgeries, 59.3 percent (n=32) involved the cardiovascular (CV) system.

Quaternary transfer to cardiothoracic ICUs from ECMO centres was required for 5.7 percent of patients (n=52). Within 28 days of quaternary transfer, major operations were performed in 42.3 percent of patients (n=22), 81.8 percent of whom (n=18) underwent surgeries involving the CV system.

ECMO successfully bridged 4.5 percent of patients (n=41) to subsequent procedures, including ventricular assistive device implantation (n=32), heart transplantation (n=8) and lung transplantation (n=1).

The overall hospital mortality rate was 50.1 percent (n=456), with an increasing trend from 5.6 percent (n=1) in 2010 to 52.6 percent (n=90) in 2019 (p_trend<0.001). In the VV-ECMO, VA-ECMO and ECPR groups, hospital mortality rates were 33.9 percent, 59.9 percent and 76.8 percent, respectively.