Climate change has led to more frequent and severe extreme heat events, as evidenced by the consequences of last summer’s extreme heat in the United States. July was the hottest month in recorded history (asamonitor.pub/3Z65ht0). According to NASA, the next few years will pose even greater temperature challenges due to the confluence of global warming with a new El Niño oceanic temperature rise. Anesthesiologists will play a critical role in creating resilient hospital infrastructure to cope with the punishing temperatures in our changing climate.
Climate change and extreme heat in the U.S.
The U.S. has been experiencing a steady rise in average temperatures over the past century due to the emission of greenhouse gases from human activity (asamonitor.pub/45FPe7w). The Intergovernmental Panel on Climate Change (IPCC) highlights that the U.S. has witnessed an increase of approximately 1.8°F (1.0°C) in average temperatures since the late 19th century (asamonitor.pub/45llgpk). This warming trend has led to more frequent and intense heatwaves across the nation.
Alarming statistics on extreme heat:
- According to the National Oceanic and Atmospheric Administration (NOAA), 2020 tied with 2016 as the hottest year on record in the U.S., emphasizing the increasing severity of heat events. The average temperature in 2020 was 54.4°F (12.4°C), 2.3°F (1.3°C) above the 20th-century average (asamonitor.pub/3smeukJ). 2023 is on track to become the hottest year, according to NASA (asamonitor.pub/3Z65ht0).
- The Centers for Disease Control and Prevention (CDC) reports that extreme heat is the leading cause of weather-related deaths in the country. Between 1999-2019, more than 10,000 people died from heat-related causes in the U.S., with an average of 702 deaths annually (asamonitor.pub/3smeukJ).
- A 2018 study estimated that heat-related mortality in the U.S. could rise to approximately 16,000 deaths per year by the end of the century if greenhouse gas emissions remain unchecked (Climatic Change 2018;155:243-60).
Impact on health complications
As temperatures continue to rise, the occurrence of heat-related illnesses has become a growing concern in the U.S. Heat-related illnesses such as heat exhaustion and heatstroke, heat cramps, and exacerbation of preexisting cardiovascular and respiratory diseases are becoming more common and can lead to life-threatening complications (asamonitor.pub/3QNs9eI). The CDC estimates that heat-related illnesses result in approximately 65,000 emergency department visits in the U.S. each year (asamonitor.pub/3QNs9eI). Anesthesiologists may encounter patients experiencing heat-induced complications before, during, or after surgical procedures, necessitating careful monitoring and management (Br J Anaesth 2002; 88:700-7).
“The CDC estimates that heat-related illnesses result in approximately 65,000 emergency department visits in the U.S. each year. Anesthesiologists may encounter patients experiencing heat-induced complications before, during, or after surgical procedures, necessitating careful monitoring and management.”
Heatstroke: Heatstroke is a life-threatening condition that occurs when the body’s core temperature rises above 104°F (40°C). Heatstroke can lead to organ failure, central nervous system dysfunction, and death if not immediately treated. According to the CDC, approximately 700 deaths annually in the U.S. are attributed to heatstroke (asamonitor.pub/3smeukJ). Anesthesiologists may encounter patients with heatstroke during surgical emergencies or because of heat-related complications following procedures. Anesthesiologists will likely be involved in the management of acute heatstroke, implementing aggressive cooling measures and maintaining cardiovascular stability until the core temperature decreases and homeostasis is restored.
Vulnerable populations: Vulnerable populations, including the elderly, young children, pregnant women, and individuals with chronic medical conditions, are at increased risk of heat-related complications (J Midwifery Womens Health 2023 68:324-32). Elderly individuals accounted for 36% of heat-related deaths in the U.S. between 1999 and 2019 (asamonitor.pub/3smeukJ). Anesthesiologists should be especially vigilant in monitoring these patients for signs of heat-related illnesses during surgical procedures. The effects of extreme heat in elderly patients can be compounded by age-related changes in thermoregulation and increased susceptibility to dehydration.
Cardiovascular and respiratory stress: Elevated core temperatures put additional strain on the cardiovascular system, leading to increased heart rate, blood pressure, and oxygen demand. Patients with cardiovascular diseases, such as heart failure and coronary artery disease, may experience worsened symptoms during heatwaves, including angina and arrhythmias (Climatic Change 2018;155:243-60). Elevated core temperature increases morbidity and mortality in patients with preexisting cardiovascular and respiratory conditions. Every 1°C increase over the threshold of the temperature-health effect curve (29°C-36°C) corresponds to a 2.7%-3.1% rise in hospitalizations for respiratory issues and a 1.4%-3.6% increase in hospitalizations for heart problems (Epidemiology 2009; 20:738-46). Notably, this impact is more pronounced for Hispanic individuals (6.1% per °C) and the elderly (4.7% per °C). High temperatures drive up admission rates for chronic airway obstruction, asthma, ischemic heart disease, and cardiac dysrhythmias (Epidemiology 2009; 20:738-46). These effects can be compounded by the air pollution from wildfires that has accompanied this summer’s heatwaves worldwide.
Rise of infectious diseases
Climate change can influence the transmission patterns of infectious diseases, with some diseases becoming more prevalent in certain regions due to changing environmental conditions. As temperatures rise, disease vectors – such as mosquitoes and ticks – can expand their range, leading to an increased risk of vector-borne illnesses.
Mosquito-borne diseases: Diseases like dengue fever, chikungunya, and Zika virus pose a significant public health threat in the U.S. According to the CDC, mosquito-borne diseases doubled in the U.S. from 2004-2016, with cases reported in nearly every state (asamonitor.pub/45eYAqO). By 2050, global warming will result in nearly 50% of the world inhabiting areas where mosquito-borne diseases thrive (Nat Microbiol 2019;4:901; asamonitor.pub/45eYAqO). Anesthesiologists can expect to treat more patients with mosquito-borne infections. Anesthesiologists should consult with infectious disease specialists in planning perioperative care, including whether infection control measures are necessary to prevent disease transmission.
Tick-borne diseases: Diseases such as Lyme disease and Rocky Mountain spotted fever are also affected by climate change. Warmer temperatures and altered precipitation patterns will impact the distribution and prevalence of ticks, increasing the risk of tick-borne illnesses in specific geographic areas. Anesthesiologists must be aware of the potential for tick-borne diseases in their practice settings and consider appropriate prophylactic measures when necessary.
Hospital infrastructure adaptation
Rising temperatures pose significant challenges to hospital operations during heatwaves. Increased energy demands for cooling systems can strain power grids, leading to power outages that impact critical medical equipment. A study by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers found that hospitals use 2.5 times the amount of energy as other commercial buildings (asamonitor.pub/3siQb73). Hospitals must plan and invest in reliable backup power sources to maintain uninterrupted health care services during extreme heat events.
Cooling systems and thermal comfort: Providing thermal comfort in health care settings is vital for patient outcomes and staff well-being. Extreme heat can significantly impact patient recovery and increase the risk of heat-related complications (asamonitor.pub/3QSGZk6). Hospitals must prioritize sustainable cooling solutions, such as energy-efficient air conditioning systems, to maintain thermal comfort in patient care areas and ORs.
“Rising temperatures pose significant challenges to hospital operations during heatwaves. Increased energy demands for cooling systems can strain power grids, leading to power outages that impact critical medical equipment.”
Building design and resilience: Hospital location and building design can mitigate some of the impact of extreme heat on health care facilities. Hospitals situated in urban heat islands, where heat is trapped due to extensive urbanization and heat-absorbing materials, may face additional challenges. A study highlighted the potential benefits of cool roofs in reducing heat island effects and improving thermal comfort inside buildings (Solar Energy 2014; 103: 682-703). Anesthesiologists should advocate for hospital locations away from heat-intensive areas and building designs that incorporate heat-resistant materials.
Climate change poses significant threats to public health and health care infrastructure in the U.S. Extreme heat events are becoming more frequent and severe, leading to heat-related health complications and stressing hospital systems. Anesthesiologists will be called upon to treat patients with life-threatening hyperthermia and will increasingly address challenges imposed by a warming planet in their daily practice. Concurrently, anesthesiologists can help guide health care institutions to invest in resilient infrastructure capable of withstanding extreme temperatures. By understanding the impact of climate change on health and infrastructure, anesthesiologists will contribute to building a more sustainable and adaptive health care system for the future.