These results support three conclusions: (1) the extent of eye-opening at ICU admission was associated with worse longitudinal SOFA scores; (2) the trait of facial skin colour itself was not associated with a worse SOFA score over time, and (3) importantly for the concept of facial monitoring techniques, facial skin colour interacted with the extent of eye-opening, modifying the association with longitudinal SOFA score. The last aligns with the observation of a lower mortality rate in patients with flushed skin and may suggest an adequate response to, e.g., infectious disease.

Prior research has established a connection between an individual's health and the characteristics of their facial appearance, suggesting that one can gauge a person's health status by examining their face [6,7,8]. One study demonstrated that persons in photographs rated as 'sick' more often had pale skin, pale lips, and partially closed eyes [2]. Another study showed that ward patients who had closed eyes, depressed lip corners, parted lips, and heads turned were more likely to deteriorate [4]. Moreover, verbal communication, body language, and facial appearance could provide valuable information about patient’s severity of injury when they enter the Emergency Department [3]. Our observations, in general, support the concept that clinical gestalt is more complex than the sum of its traits.

In the past decade, phenotypic decision support for rare disorders has been improved by developing innovative facial recognition tools, such as GestaltMatcher [9,10,11]. It is fascinating whether facial or overall appearance derived by intelligent monitoring sensors can aid in care for hospitalized patients by providing real-time information for predicting disease progression. Smart cameras or intelligent systems have the potential to decrease the monitoring workload for nurses, optimizing workforce efficiency and enabling them to concentrate more on providing care. However, further research is needed to explore this possibility.

Facial assessment of a large cohort of acutely admitted patients was conducted shortly after admission when disease severity was minimally impacted by interventions or treatment decisions.

Limitations include the fact that we measured only two traits of facial appearance. Our study is a single-center study, and we did not record inter-observer agreement. Further, although the pictograms were developed to be suitable for all skin types, it is crucial to consider that individual skin tones can still influence the reported colour of the cheeks. Estimating facial skin colour may pose a challenge with individuals having darker skin tones, which could lead to an underestimation of associations between facial skin colour and longitudinal SOFA scores in our study. However, this limitation underscores the importance of incorporating inclusivity in the evaluation of facial appearance through the integration of advanced technologies in future clinical research [12].

Also, ethnicity is not registered in Dutch hospitals; this limitation hinders the external validity of this study. In addition, the neurological component of the SOFA score is derived from the Glasgow Coma Scale, which assesses eye-opening. This evaluation involves stimulating the patients to open their eyes. The patient was only observed in our study; therefore, this possible influence may only apply to mechanically ventilated patients. This could have led to underestimation of the results.