Climate change impacts on emergency departments

July 11, 2021

July 26, 2021

Hyun Choi, Emergency Medicine Consultant (Hamad General Hospital, Qatar)

Aftab Arif, Hamad General Hospital, Qatar

What are the impacts of [extreme heat] on [climate sensitive emergency health conditions] and [emergency departments]?

Climate change is the biggest global health threat of the 21st century. According to the recent Intergovernmental Panel on Climate Change, the global mean temperature is projected to rise by 1.4 to 5.8 degrees by the end of the century. Extreme temperatures overwhelm the body's heat regulatory mechanism, and multi-system organ dysfunction results.

In light of recent global heatwaves, it is imperative that emergency care clinicians appreciate the diversity of climate sensitive emergency health conditions and their impacts on emergency care systems.

Literature search was conducted from Medline, Embase, Global Health and grey literature databases. Articles were limited to English language published between 1990 and August 2020.

[exp Emergency Medicine/ OR exp Emergency Medical Services/ OR exp Emergency Service, Hospital/ OR exp Resuscitation/ OR exp Disaster Medicine/ OR exp Emergency Treatment/ OR exp Emergencies/ OR (emergency adj2 (system* or care or service*)).mp. OR (emergency adj1 (medicine or care or room or department* or unit* or service* or practice or treatment*)).mp.] AND

[exp Climate Change/ OR exp Greenhouse Effect/ OR exp Greenhouse Gases/ OR exp Global Warming/ OR (global adj1 (warming or heating)).mp. OR Greenhouse Gases/ OR ((weather or environment) adj1 change*).mp.] AND

[exp Cardiovascular Diseases/ OR exp Respiratory Tract Diseases/ OR exp Respiratory Tract Infections/ OR exp Asthma/ OR exp Pulmonary Disease, Chronic Obstructive/ OR exp Cerebrovascular Disorders/ OR
exp Kidney Diseases/ OR exp Heat Stroke/ OR exp Communicable Diseases/ OR exp Bacterial Infections/ OR exp Virus Diseases/ OR exp Parasitic Diseases/ OR exp Mycoses/ OR exp Zoonoses/ OR exp Pandemics/ OR exp Diarrhea/ OR exp Mental Health/ OR exp "Wounds and Injuries"/ OR exp Death ]

Limit to English

The search yielded a total of 192 articles after the removal of duplicates. 21 articles addressed heatwaves and their impacts on emergency health and emergency care systems.
These were all peer reviewed original research articles.

There is no standardised definition of a heatwave. The accepted definition refers to the elevation of an ambient temperature above an average threshold sustained for a defined period of time. This threshold varies geographically. The heterogeneous nature of existing data, combined with the inherent diversity of climate-specific epidemiological and socio-economic variables of each locality present a significant logistic challenge in conducting systematic reviews on this topic.

Extreme heat is one of the many climate change driven effects, along with increased air pollutants, climatic disasters and altered infectious disease epidemiology, inter alia. This review focused on the impacts of extreme heat on emergency departments.

Both increased all-cause and heat-related (heat exhaustion, heat stroke, dehydration, acute renal failure, electrolyte imbalances) ED visits are reported with increased ambient temperatures around the world. The highest relative increase is observed among the elderly (> 65 years), the young (< 5 years), males, and those with non-communicable disease.

Increased ED visits are also reported for the following conditions; cardiovascular disease, diabetes, renal colic, appendicitis, gastrointestinal infectious disease, arthropod bites, chronic renal failure, respiratory disease, injury, and mental health disorders.

The elderly are disproportionately vulnerable to the effects of extreme heat due to their sensory, cognitive and physical disabilities, compounded by limited social support and financial means.
The bigger surface to body ratio of young children increases their vulnerability to heat stress and dehydration.

The magnitude of heatwave influence on ED visits varies across studies, and is dependent on the geographical, demographic, and socioeconomic characteristics of the community.

Most studies did not control for individual and community adaptation behaviors, for example the installation of air conditioning, fluid intake, existing community health system infrastructure and support networks, etc. Absence of measures to control for effect modifiers precludes meaningful comparison of outcomes between areas with different geographical, demographic and health infrastructure variables.

Public health response could support targeted interventions at a local level, for example public education to vulnerable groups to avoid exposure to risk factors, and avoidance of prescribing high-risk medications (e.g. diuretics, antipsychotics, anticholinergics) which interfere with the body’s thermoregulation and increase vulnerability to extreme heat among the elderly.

Finally, most included studies were conducted in high income countries which have the resources to build climate resilient emergency care pathways. Further research is urgently needed to develop empirical examples that inform adaptation measures across a range of low- and middle-income countries where the impact of climate change is likely to be most profound.

The review demonstrates that heatwaves are placing increasing demands on the emergency care systems. Extreme heat results in excess ED visits in many countries with multi-organ impacts resulting in excess morbidity.

1. Basu R et al . The effect of high ambient temperature on emergency room visits
2. Hess JJ et al. Summertime acute heat illness in U.S. emergency departments from 2006 through 2010: analysis of a nationally representative sample
3. Knowlton K et al. The 2006 California heat wave: impacts on hospitalizations and emergency department visits
4. Wang Y et al. High temperatures and emergency department visits in 18 sites with different climatic characteristics in China: Risk assessment and attributable fraction identification
5. Watson KE et al. The impact of extreme heat events on hospital admissions to the Royal Hobart Hospital
6. Schaffer A et al. Emergency department visits, ambulance calls, and mortality associated with an exceptional heat wave in Sydney, Australia, 2011: a time-series analysis.
7. Wang YC et al. Association between temperature and emergency room visits for cardiorespiratory diseases, metabolic syndrome-related diseases, and accidents in metropolitan Taipei
8. Cheng J et al. Cardiorespiratory effects of heatwaves: A systematic review and meta-analysis of global epidemiological evidence
9. Lavigne E et al. Extreme ambient temperatures and cardiorespiratory emergency room visits: assessing risk by comorbid health conditions in a time series study
10. Mullins and Whitenjkkm. Temperature and mental health: Evidence from the spectrum of mental health outcomes
11. Toloo GS et al. The impact of heatwaves on emergency department visits in Brisbane, Australia: a time series study
12. Imai N et al . Seasonal prevalence of hyponatremia in the emergency department: impact of age
13. Xu Z et al. Assessing heatwave impacts on cause-specific emergency department visits in urban and rural communities of Queensland, Australia
14. Vicedo-Cabrera AM et al. Sex differences in the temperature dependence of kidney stone presentations: a population-based aggregated case-crossover study
15. Cervellin G et al. Mean temperature and humidity variations, along with patient age, predict the number of visits for renal colic in a large urban Emergency Department: results of a 9-year survey
16. McTavish RK et al. Association Between High Environmental Heat and Risk of Acute Kidney Injury Among Older Adults in a Northern Climate: A Matched Case-Control Study
17. Sherbakov T et al. Ambient temperature and added heat wave effects on hospitalizations in California from 1999 to 2009
18. van Loenhout JAF et al. Heat and emergency room admissions in the Netherlands
19. Newitt S et al . The use of syndromic surveillance to monitor the incidence of arthropod bites requiring healthcare in England, 2000–2013: a retrospective ecological study
20. Kingsley SL et al. Current and Projected Heat-Related Morbidity and Mortality in Rhode Island
21. van der Linden N et al. The use of an 'acclimatization' heatwave measure to compare temperature-related demand for emergency services in Australia, Botswana, Netherlands, Pakistan, and USA