Climate Change and the Intensive Care Unit

For many of us, climate change is intimidating but distant. We are worried about an abstract future, we hear all the time about how quickly it is approaching, and we may be frustrated with how much is asked of us and how little it seems to matter what we do. We may want the health system to do more about it.¹  As clinicians practicing in the intensive care unit (ICU), the climate is particularly remote—in our units, we control and standardize the climate in every patient’s room. The weather can feel quite far away indeed. Yet, climate change is manifesting in our local communities, more every day, and this touches our daily experience in the ICU more than we may recognize. Effects seen in the ICU range from the immediate impact of catastrophic weather events to the secondary effects of infectious disease spread and the long-term impact on chronic disease exacerbation, all of which can affect the lived experience of patients and clinicians in the ICU. Intensive care, unsurprisingly, has a dramatically larger carbon footprint than acute care; the difference is comparable to putting the patient in an airplane.^2–4  Furthermore, the ICU’s footprint is dramatically higher in the United States than in other countries.^3,4  Given the impact on our patients and the potential for improvement in our units, considering climate change is part of our social responsibility in the ICU.

Extreme weather events with profound local impact are increasingly common. Last year was North America’s warmest on record; we saw record wildfires in Canada that severely decreased air quality in the United States; 37 storms and 27 hurricanes hit US coasts, including a storm in September that caused flash flooding in New York City, prompting a state of emergency and widespread disruption of transportation and other services. We saw the deadliest US wildfire in a decade, which leveled the town of Lahaina in Hawaii. Hurricane Otis, a category 5 storm, caused widespread devastation in Mexico. We experienced the extremes of precipitation and drought, from a total of 32 trillion gallons of rain and snow hitting California in January alone to record low water levels in the Mississippi River causing barges and ships to run aground.⁵ 

These anomalies and the general impact of climate change can lead to increased acute care and ICU utilization, in particular through heat-related illness, acute stroke and myocardial infarction, heart failure exacerbations,⁶  and acute exacerbations of asthma and chronic obstructive pulmonary disease^7–10  and other respiratory issues.¹¹  The increase in vector-borne infectious diseases because of climate change is well documented.¹²  Infectious diseases are also related to heat and access to clean water; in Los Angeles, a cluster of Aeromonas infections was noted in 2 ICUs, resulting in several deaths due to resistant microorganisms; these infections were most likely associated with plumbing issues in the context of high outdoor temperatures.¹³  Many of us have personally cared for ICU patients with all of these problems in the past year, and in many cases, we could connect exposure to climate events with the increased risk of critical illness. We will most likely see further connections to typical ICU problems such as diabetic ketoacidosis, sepsis, kidney and liver failure, substance abuse, suicide attempts,¹⁴  burns,¹⁵  and cardiac arrest.

Climate change has a disproportionate impact on the health of the most vulnerable in society,¹⁶  and this is reflected in ICU admissions as well, with many patients covered via Medicare and Medicaid.¹⁷  Disenfranchised patients have more social stressors—such as housing instability and food insecurity—and less social support, all of which may contribute to worse outcomes and experience in the ICU, in part because these patients are more vulnerable to these exposures and because they also have less access to preventative care, including timely and high-quality disease management.¹⁸  These patients live and work in environments that increase risk further, such as urban heat islands, agricultural worksites, or highway-adjacent homes with poor air quality.

Intensive care clinicians have a powerful and relevant voice for climate advocacy. This voice can be used to advocate for reducing the carbon footprint of the ICU, improving the resiliency of health care systems, and providing staffing and material resources to be able to meet the needs of our communities at their most vulnerable moments.

The carbon footprint of the ICU is largely driven by energy use, in particular for heating, ventilation, and air conditioning—which is influenced by the numbers of patients and length of stay.^3,4,19  Thus the 2 best ways to reduce our footprint are by advocating for a transition to renewable energy sources and (more in our direct control) shortening ICU length of stay by reducing the risk of complications. These 2 efforts align closely with modern patient-centered ICU goals that are often espoused but difficult to achieve, such as reducing indwelling catheter use, following evidence-based guidelines for daily awakening and breathing trials to minimize duration of mechanical ventilation and reducing the impact of sedatives, improving appropriate prophylaxis and avoiding unnecessary medications, converting to oral medications, consulting palliative care staff early, and reducing delirium risk.^19–21  We should also consider the contribution of clinical research in the ICU to achieving patient-centered goals while considering social responsibility—indeed, what benefits patients in the short term may also benefit the greater good.

Health systems can also support ICU patients and clinicians by being more prepared for climate emergencies.²²  Many hospitals in cities experiencing overwhelming COVID-19 surges developed local prediction tools, and some machine learning algorithms were developed to predict ICU admissions in the coming week as well.²³  We could develop these Incident Command Systems further to predict the need to surge capacity as a result of climate events and other challenges. Predicting the need for ICU capacity from a respiratory pandemic that was largely stereotypical in its presentation is very different from predicting acute care strain from climate events, but some models already exist.²⁴  On a practical level, such prediction translates to knowing your schedule in advance versus being called in urgently in the middle of a storm without childcare or other necessities prepared. Some cities and states have already developed these programs.²⁵  Moreover, ICU clinicians can contribute directly to developing clinical pathways for climate-related problems such as heatstroke to respond more efficiently in a crisis.²⁶  Clinical research could accelerate the development and dissemination of such programs and pathways.

Critical care clinicians should continue to advocate for and insist on improved staffing and availability of human and material resources in everyday practice.²⁷  Most ICUs are strained on a day-to-day basis; nursing, respiratory therapy, and other staffing shortages are significant and widespread. Catastrophic weather events can also cause massive disruptions to supply chains that affect the medications we rely on in critical care, a phenomenon we experienced all too recently during COVID-19 surges.²⁸  How can we be prepared for future surges in demand for ICU care when we are struggling to manage the day-to-day experience of critical care?

At the bedside, we should never prioritize sustainability or any other goal over the best clinical care for the patient; we should not be advocating for changes to clinical practice for sustainability reasons alone. But there is tremendous potential for advocacy from the ICU for a more sustainable and prepared hospital, and often, the best interests of an individual patient overlap with sustainability goals as well.²  Beyond the bedside, the voice of the critical care clinician may seem small. It is difficult to imagine using such a voice to influence the hospital’s energy sourcing or the way the emergency department addresses heatstroke. Despite this, the voice of even one clinician can act as a beacon.²⁹  Many who weathered the pandemic with you are also worried about the coming storms.³⁰  You may be surprised to see how many voices join your call; climate advocacy is often supported by professional societies^31–34  and incorporated into clinical education.³⁵  There are step-by-step guides for increasing sustainability in the ICU for every member of the ICU team.^36,37  You can create or join a hospital-based or even an ICU-specific sustainability team—many are nurse led and numerous statewide and regional groups already exist to support you.^38,39  Addressing climate change by reducing the ICU carbon footprint, developing Incident Command Systems, building relevant clinical pathways, and ensuring robust staffing are all within the purview of the critical care community. We need to advocate for substantial improvements or else we will find once more that crisis standards of care have become the norm.