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The new heatwave and extreme heat protection plan

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VOL: 101, ISSUE: 22, PAGE NO: 26

Terry Hainsworth, BSc, PGC, RGN, is clinical editor, Nursing Times

In the UK we are very aware of the dangers of extreme cold weather, especially for older or frail people, and there are social and health care policies in place, such as winter fuel payments, to protect these vulnerable groups. However, this country is not used to hearing government health warnings about the dangers of extreme heat. Nevertheless, it has been predicted that by the 2080s summer heatwaves like the one experienced in the UK in 2003 will happen every year (Department of Health, 2005a).

 

In the UK we are very aware of the dangers of extreme cold weather, especially for older or frail people, and there are social and health care policies in place, such as winter fuel payments, to protect these vulnerable groups. However, this country is not used to hearing government health warnings about the dangers of extreme heat. Nevertheless, it has been predicted that by the 2080s summer heatwaves like the one experienced in the UK in 2003 will happen every year (Department of Health, 2005a).

 

 

Periods of high temperature pose a significant threat to the health of older or frail people. In London during August 2003 deaths among people aged more than 75 years old rose by 60 per cent (DoH, 2005b). There is evidence to suggest that this increase in deaths was not simply due to people who would have died in the next few weeks dying sooner, but that these were extra deaths as a direct result of heat-related conditions (DoH, 2005a).

 

 

The DoH has now issued a plan to protect the health of vulnerable people during heatwaves and extreme heat (DoH, 2005a). This is especially important because, unlike the problems associated with cold snaps, the risks to health from a heatwave follow within one or two days of the rise in temperature, resulting in a very limited time for effective action to take place. Therefore nurses all need to be aware of the health risks that follow rises in temperature and ensure that they are able to take the appropriate action to protect high-risk groups (Box 1).

 

 

Heat-associated illness
There is a risk of developing heat exhaustion and heatstroke during extremely hot weather (DoH, 2005a). These conditions are related and exist along a continuum of severity (Kunihiro and Foster, 2004):

 

 

- Heat exhaustion occurs when the body can no longer dissipate heat due to extreme environmental conditions or increased heat production;

 

 

- Heatstroke is a progression of heat exhaustion and is extreme hyperthermia with thermo-regulatory failure.

 

 

Heat-associated illness is caused by dehydration, electrolyte losses, and a failure of the body’s thermoregulatory mechanisms. In the initial stages the body compensates for the increased heat, but eventually its thermoregulatory mechanisms fail and hyperthermia develops. This can accelerate and result in end-organ damage (Kunihiro and Foster, 2004).

 

 

In a hot environment the body normally loses excess heat through radiation and evaporation. However, when temperatures become very high (more than 35 degsC), evaporation becomes the only means of heat loss. The body attempts to lower the core temperature via renal and splanchnic vasoconstriction and peripheral vasodilatation. Eventually this fails and less heat is carried away from the core, resulting in hyperthermia. Cerebral oedema and cerebrovascular congestion increase intracranial pressure. This, combined with a decreased mean arterial pressure, causes cerebral blood flow to decrease, eventually resulting in central nervous system dysfunction (Kunihiro and Foster, 2004).

 

 

Older people are at increased risk of heat-associated illness because of underlying illness, use of medication, declining adaptive thermoregulatory mechanisms, and limited social support networks. Neonates have an increased risk of heat-associated illness because of their poorly developed thermoregulatory mechanisms.

 

 

Heat exhaustion symptoms are often non-specific and may be insidious in onset. These symptoms, which often resemble a viral illness, include (DoH 2005a):

 

 

- Fatigue and weakness;

 

 

- Nausea and vomiting;

 

 

- Headache and myalgias;

 

 

- Dizziness;

 

 

- Muscle cramps and myalgias;

 

 

- Irritability.

 

 

Any or all of the symptoms of heat exhaustion may be present in heatstroke, along with additional CNS dysfunction. Symptoms include tachycardia, increased pulse pressure, decreased cardiac output, decreased diastolic blood pressure, hallucinations, altered mental status; confusion, disorientation and coma. The patient’s temperature is usually higher than 41 degsC although temperature readings may be lower if cooling measures have been used (Kunihiro and Foster, 2004).

 

 

The plan
The new Department of Health plan recommends action for health and social care services in the event of a heatwave (DoH, 2005a). It includes a plan of action to be used both before and during a severe heatwave in England.

 

 

One of the core elements of the plan is a ‘Heat-Health Watch’ system, which will operate from 1 June to 15 September. This will be based on Met Office forecasts, and will trigger one of four levels of response (DoH, 2005a):

 

 

- Level 1: awareness is the minimum state of vigilance;

 

 

- Level 2: alert is triggered as soon as the Met Office forecasts threshold temperatures for at least three days ahead or if there is an 80 per cent chance of temperatures being high enough on at least two consecutive days to have significant effects on health;

 

 

- Level 3: heatwave is triggered as soon as the Met Office confirms that threshold temperatures have been reached in any one region or more;

 

 

- Level 4: emergency is reached when the effects of a heatwave extend outside health and social care, such as power or water shortages and/or where the integrity of health and social care systems is threatened.

 

 

During the ‘Heat-Health watch’ period, the Health Protection Agency will be monitoring NHS Direct calls and a sample of GP practices’ appointments to assess the effect that the weather is having on health.

 

 

Implications for practice
Treatment of heatstroke requires urgent action. In the community setting an ambulance should be called and the patient should be cooled as quickly as possible using a cool shower, sprinkling them with water or wrapping them in a damp sheet. The patient’s temperature should be recorded and they should be encouraged to drink if they are conscious. Antipyretics such as aspirin or paracetamol should not be given.

 

 

The level 1 awareness phase is a period of health promotion and preparation. During this time individuals who are at particular risk from extreme heat, especially those aged more than 75, need to be identified. This is the responsibility of PCTs. Many of those at risk are likely to already be receiving care from nursing teams in the community or in residential or nursing homes. These teams should ensure that at-risk patients are aware of the risks of extreme heat and what action they should take.

 

 

Changes may need to be made to individual care plans to include necessary changes in the event of a heatwave. This may include initiating daily visits by formal or informal carers to check on people living alone.

 

 

In addition simple protective measures, such as installing proper ventilation and ensuring fans and fridges are available and in working order may need to be undertaken.

 

 

During this awareness period a review of surge capacity and the need for, and availability of, staff support in the event of a heatwave, should also be undertaken.

 

 

Some drugs are theoretically capable of increasing the risk of heat-associated illness in susceptible individuals. These include:

 

 

- Drugs that cause dehydration or electrolyte imbalance;

 

 

- Drugs likely to reduce renal function;

 

 

- Drugs that interfere with thermoregulation.

 

 

It may be worth careful review of medication for these patients, assessing the risks and benefits of any changes to their regimen.

 

 

lf threshold temperatures are forecast (level 2 alert phase) a warning will be broadcast to the public via both television and radio weather reports. Nurses therefore will need to be familiar with the plan and advise and reassure patients appropriately.

 

 

As soon as possible after the alert level is announced, and no later than the second day of a heatwave if level 3 is reached, PCTs and local social services must distribute DoH advice to all those identified as at risk, and home visits should be started where appropriate.

 

 

In the event of a ‘major incident’ (stage 4) being declared, all existing emergency policies should be followed.

 

 

- For related articles on this subject and links to relevant websites see www.nursingtimes.net

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