Healthcare systems are increasingly recognized as significant contributors to global climate change, generating an estimated 4 %–5% of worldwide greenhouse gas emissions [1]. Within this landscape, recent analyses confirm that ICUs represent major environmental hotspots within hospitals. In the Netherlands alone, hospital care produces approximately 17.6 kilotons of CO2 emissions, 4,803 kilotons of waste, 55 % of which is plastic, and the ICU is among the primary contributors to this footprint [2]. Their high technological dependency, reliance on single-use materials, and continuous energy consumption amplify their environmental impact, positioning them as a critical site of ecological concern in hospitals [3]. Treating a single critically ill patient can generate substantial volumes of waste and demand large amounts of energy and water, ultimately escalating landfill deposition, incineration emissions, and associated ecological costs [4], [5], [6]. Beyond their ecological footprint, these inefficiencies also challenge healthcare operations, creating vulnerabilities in supply chains, increasing financial pressures, and threatening continuity of care during resource shortages [7]. Consequently, embedding environmental sustainability into critical care practice has become both a clinical and an ethical imperative.

Despite the urgency, sustainability in healthcare has been predominantly addressed through technical or structural interventions, such as waste segregation, recycling initiatives, or adoption of reusable equipment [4], [8], [9]. While necessary, these measures remain insufficient to capture the complexity of everyday clinical practice. In ICUs, sustainability is shaped not only by technologies but also by professional values, shared norms, and collective meaning systems that orient behavior [10]. Nurses, who spend the greatest proportion of time at the bedside, act as cultural agents as well as practitioners: their micro-level decisions, such as selecting equipment, preventing waste, or adjusting environmental conditions, are guided by what their professional community perceives as ethically appropriate and clinically legitimate [11], [12]. These situated actions are embedded within a wider socio-cultural configuration in which identity, moral responsibility, and peer expectations define how ecological awareness is translated into care [13], [14]. Professional culture thus operates as a key lever for advancing sustainability, mediating the adoption, legitimation, and normalization of environmentally responsible practices in intensive care. Understanding these cultural dynamics provides the conceptual foundation for examining how sustainability is expressed and negotiated through discourse [15], [16], [17].

This gap is particularly significant because discourse, understood as the way sustainability is articulated, negotiated, and reproduced within professional narratives, both reflects and influences how ecological values are prioritized in workflows, education, and organizational strategies. Rather than implying a linear causality, this relationship is cyclical: language both expresses existing cultural orientations and provides the medium through which new ones are formed and legitimized. In this perspective, analyzing discourse offers a way to map how cultural meanings of sustainability circulate within intensive care nursing and how these meanings create the conditions for change in practice and education [18], [19].

This study addresses this gap by exploring the cultural and behavioral foundations of sustainability in intensive care nursing through the analysis of nurses’ narratives. Lexicometric exploration refers to a computational approach that statistically examines word co-occurrences to reveal latent semantic structures within discourse. This method was selected because it provides a transparent and replicable means of mapping how sustainability is linguistically constructed by ICU nurses, complementing qualitative interpretation with structural evidence. This strategy enables the identification of the cultural and behavioral dimensions through which sustainability is understood in critical care.