heat waves

see also:

• Vic DHS patient information sheet - preventing heat stress
• Vic DHS community resources for managing heatwaves
• WH preparing for heatwaves (intranet only)
• heat illness and heat stroke

• heat waves are common in Australia
• in the southern parts of Australia, they are particularly a problem in January when 3-7 days in a row of 40degC or more are possible
• such heat waves are associated with an increase in mortality, particularly of the elderly who are at high risk
• Melbourne has the highest number of deaths from heat waves of Australian capital cities, although Adelaide beats Melbourne on a per capita mortality basis - this is thought to be the substantial change in temperature over a period of days compared to recent levels which does not allow time to acclimatise as occurs in the northern cities ¹⁾

• Melbourne's heat wave of Jan 2014:
  • hottest heatwave on record with 4 consecutive days above 41deg C in Melbourne, with max. 44degC, max. over 45degC in Geelong.
  • Melbourne's average temperature for the day exceeded 35degC for 3 of these days!
  • 1st time that Adelaide, Melbourne and Canberra all reached 40degC on the same two consecutive days!
  • heart attack rates 4x more than usual
• Melbourne's heat wave of Jan 2009:
  • it appears that during the record 3 days Jan 28th-30th inclusive when Melbourne's max. temperature exceeded 43deg C each day and peaked at 45.4degC, with associated regional loss of power, there were at least 100 excess deaths reported in Melbourne and over 200 in south-east Australia. Most were the elderly who died at home presumably due to exacerbation of their cardiac failure. The Alfred Hospital reported a 70% rise in admissions, including the subsequent days, while the ambulance service had their busiest days on record with jobs double the average. Deaths reported to the Coroner during the heatwave were 2.5 times more than at the same time last year. It appears that deaths in those aged > 65yrs increase by 15% on days when average daily temperature exceeds 30degC in Melbourne - during this heat wave average temperatures were ~35degC. ²⁾

• risk factors include housing types, age, health and socio-economic status of the population
• a Monash Uni study published in 2014 identified suburbs most affected by heatwaves include Sunshine, St Albans, Glenroy, Coburg, Preston, Reservoir, Clayton and Dandenong

• dehydration
  • heat illness and heat stroke
  • renal colic
  • increased falls
  • impaired cognition, increased accidents
  • increased toxicity of medications such as digoxin, warfarin, and lithium carbonate
  • exacerbation of pre-existing illnesses
• gastroenteritis from overly warm food storage or excessive people in public swimming pools
• respiratory illness / exacerbation asthma
• potential electrical overload from excessive loads from reverse cycle air conditioners resulting in “brown outs” with loss of availability of air conditioners, refrigeration, fans
• potential public transport outages - track failures, power failures, etc
• bushfire risk

• the following is as published by Victorian Department of Health Dec 2012

• Understand the mechanisms of heat illnesses, clinical manifestations, diagnosis and treatment.
• Recognise early signs of heatstroke, which is a medical emergency.
• Be aware of how to initiate proper cooling and resuscitative measures.
• Be aware of the risk factors in heat-related illness.

• Identify patients at risk and educate them about heat illnesses and prevention.
• Educate carers of children, older people and people with cognitive impairment or disability.
• Include a pre-summer medical assessment and heat advice into routine care for people with chronic disease (reduction of heat exposure, fluid intake, medication).
• Be aware of potential side effects of medicines and adjust dose if necessary.
• Be aware that high temperatures can adversely affect the efficacy of drugs.
• Make decisions on an individual basis (there are no standards for alteration in medications during hot weather).
• Monitor drug therapy and fluid intake, especially in the older people and those with advanced cardiac diseases.
• Encourage appropriate behaviour such as reducing excessive clothing, using cooling devices at home and discourage avoidance of fluids due to continence issues.

• Appoint a person responsible for planning a heatwave response.
• Hold team meetings to discuss the practice response to a heatwave, develop a written policy, review the practice triage policy and conduct yearly heatwave meetings prior to summer to refresh practice staff.
• Develop and implement a communication policy to keep staff updated if a heatwave is forecast.
• Keep in contact with the local Divisions of GP for communication from the Chief Heath Officer.
• Ensure the practice is heatwave-friendly for patients and staff with a cool waiting room, water available, blinds closed to block the sun and staff breaks for drinks.
• Have phone numbers of key resources within easy access – emergency departments, local HACC services, RDNS and website of Department of Health heatwave resources.
• Have up-to-date heatwave take home resources for patients and their carers.
• Have a plan in case power goes out, for example what to do with vaccine fridges.
• Consider adding a question on the over 75 health assessment that asks a patient to consider their personal care during a heatwave.
• Think about heatwave planning for all vulnerable groups when writing GP Management Plans.
• Remember the practice is a community service which may have additional responsibilities during a heatwave.
• Plan for staff shortages, for example, if there is a Code Red Day or the GP is also the VMO.
• After the heatwave, have an evaluation meeting with staff to discuss how they dealt with it, what went well, what needs improvement and provide feedback to the Division of GP.

• During hot weather, people need to drink even if they are not thirsty.
• Each older person or patient needs to receive personalised drinking recommendations depending on their health status, particularly those who have a decreased perception of thirst.
• Carers also need to maintain adequate hydration.
• Fluids are not just limited to water; they can be icy poles, weak tea or cordial.
• Salt tablets, sports drinks or electrolyte-carbohydrate supplements offer no benefits and may be harmful because of high osmotic load.
• Excessive drinking of pure water can lead to severe hyponatraemia, potentially leading to complications like stroke and death.

• Commonwealth Respite and Carelink Centre:
  • Careline 1800 052 222 (Business Hours) or 1800 059 059 (After‑Hours Emergency Respite)
• Veterans’ Home Care Agency assessment service:
  • 1300 550 450 (Business Hours) (for emergency after-hours respite call Careline above)
• Annecto Emergency
  • After‑Hours Response Service (Victorian) 1800 72 72 80 (5pm–9am weekdays, 24 hours weekends and public holidays).
  • Free short term personal care, respite crisis management, telephone and in home support for older people, people with disability or carers who do not have funded assistance.
• Local governments often provide respite services.