From carbon cost to climate care: Greening our intensive care units

Table 1 Major contributors to the environmental footprint of intensive care units

Component	Relative contribution	Principal drivers
Energy and infrastructure	Dominant	Heating, ventilation, and air-conditioning, continuous power demand
Consumables and waste	High	Single-use devices, regulated waste
Pharmaceuticals	Moderate-high	Injectables, wastage
Medical gases	Lower but non-trivial	Oxygen supply chain, N2O
Equipment and capital goods	Sustained background	Manufacturing, standby power

Relative contribution varies by setting and is influenced by local infrastructure, clinical practice, and energy mix.

Table 2 Illustrative international examples of emerging green intensive care unit models

Country/region	Health system/initiative	Scope of sustainability action	Key features relevant to ICU practice
United Kingdom	National Health Service	System-wide net-zero strategy	National commitment to net-zero emissions; phase-down of high-global-warming-potential inhaled anaesthetics; ICU-level initiatives focusing on waste segregation, procurement reform, and infrastructure optimisation
United States	Integrated healthcare systems (e.g., kaiser permanente)	Organisation-wide sustainability programs	Carbon-neutral operations; ICU-led “Green Teams”; device reprocessing; transition to reusable patient care items; energy-efficient building systems
Australia	Clinician-led ICU sustainability programmes	Multicentre research and practice initiatives	Life-cycle assessments in ICUs; adoption of reusable gowns and underpads; reduction in low-value blood testing; incorporation of sustainability into ICU redesign
New Zealand	Public hospital networks	Medical gas and equipment optimisation	Elimination of nitrous oxide use in selected ICUs; transition to alternative analgesia and sedation strategies; waste reduction initiatives
Netherlands	National ICU sustainability networks	Policy-supported institutional change	Circular procurement practices; waste reduction strategies; integration of sustainability within national critical care frameworks
Low- and middle-income settings	Institution-level ICU practices	Resource-constrained adaptations	Emphasis on equipment reuse and repair, extended device lifespan, and supply resilience, often driven by necessity rather than environmental intent

Examples are illustrative and reflect heterogeneous, context-specific approaches rather than uniform national practice. ICU: Intensive care unit.

Table 3 The 5Rs of sustainability in the intensive care unit: Practical applications and clinical benefits

Principle	ICU application	Clinical benefit
Replace/avoid	Avoid non-evidence-based tests (e.g., routine daily imaging or laboratory panels). Replace high-impact therapies where appropriate[31,35,37,44]	Prevents overtreatment. Reduces iatrogenic harm and patient discomfort. Lowers cognitive load
Reduce	Optimise medication preparation and overfill. Minimise overstocking, reduce unnecessary energy use and room entries[28,31,35,44]	Improves efficiency without compromising readiness. Reduces error risk and staff workload
Reuse	Use durable gowns and linens, metal instruments, reusable laryngoscope blades, reprocessable bronchoscopes[19,27,31,35,44]	Lowers waste and cost while maintaining infection-control safety and procedural reliability
Recycle	Segregate clean packaging, plastics, PVC items. Reduce red-bag waste through improved classification[15,16,18,31,35]	Reduces hazardous-waste costs, improves compliance. Engages frontline staff
Rethink	Re-evaluate routines, adopt tele-ICU and digital workflows, redesign care environments and infrastructure[31,35,44,52]	Enhances patient comfort, staff wellbeing, system resilience and innovation

Adapted from published intensive care unit sustainability consensus guidance and health-system decarbonisation frameworks. ICU: Intensive care unit; PVC: Polyvinyl chloride.

Table 4 Timeline of sustainable intensive care unit interventions across implementation horizons

Timeframe	Clinician actions	Administrator actions	Policymaker actions
Short (3-6 months)	Energy conservation, waste segregation, reusables, green teams	Recycling infrastructure, minor HVAC optimisation, audits	Guidance, pilot funding
Medium (6-18 months)	De-implementation of low-value care, protocol updates	Formal green plans, energy upgrades, procurement reform	Accreditation standards, infrastructure funding
Long (> 18 months)	Sustainability embedded in training, clinical leadership	Net-zero infrastructure, renewables, circular supply chains	Net-zero mandates, regulation

HVAC: Heating, ventilation and air conditioning.

Table 5 Proposed outcome domains and measurement indicators for evaluating green intensive care unit initiatives

Outcome domain	Indicator (examples)	Unit of measurement	Suggested frequency	Comments/rationale
Environmental impact	Carbon footprint per ICU bed-day	Kg CO2e/bed-day	Quarterly	Normalised to occupancy; life-cycle-based estimates where feasible
	Energy consumption	kWh/patient-day	Monthly	Adjust for seasonal variation and case-mix
	Water consumption	Litres/patient-day	Monthly	Includes dialysis, sterilisation, and cleaning processes
	Waste segregation compliance	% correctly segregated	Monthly audit	Proxy for staff adherence and training effectiveness
Pharmaceuticals and consumables	Drug wastage rate	% discarded doses	Monthly	Prioritise high-cost and high-volume medications
	Single-use device utilisation	Devices/patient-day	Quarterly	Tracks opportunities for rationalisation or substitution
Clinical safety and quality	Adverse event rate	Events/1000 patient-days	Quarterly	Sustainability initiatives must remain non-inferior to baseline outcomes
	ICU mortality and length of stay	% mortality; days	Quarterly	Ensures environmental actions do not compromise care
Economic sustainability	Cost savings from green initiatives	Local currency/year	Annual	Encouraged reinvestment into patient care or infrastructure
	Energy and waste disposal costs	Currency/bed-day	Quarterly	Captures financial co-benefits of sustainability measures
Organisational and cultural outcomes	Staff trained in green practices	% of ICU workforce	Annual	Proxy for institutional engagement and culture change
	Participation in green programmes	% participation	Annual	Reflects leadership support and behavioural adoption
Governance and scalability	Number of audits/reviews conducted	Count/year	Annual	Indicator of continuous improvement cycles
	Inter-institutional benchmarking	Yes/no	Annual	Facilitates knowledge sharing and policy integration

CO₂e: Carbon dioxide equivalents; ICU: Intensive care unit.