Annals ofBurns and Fire Disasters - vol. VIII - n. 4 - December 1995

CONSIDERATIONS ON INTENSIVE CARE IN ELDERLY BURN PATIENTS

Divisione di Chirurgia Plastica e Terapia delle Ustioni, Ospeclale Civico, Palermo, Italy

SUMMARY. Advanced age is a determinant factor that inay cause death in burn patients, due to progressive involution of the physiological functions of various organs and systems, the onset of chronological pathological conditions, and the organism's reduced capacity to react to therapy. These three main factors are analysed in detail, in relation to the skin and the respiratory, cardiocirculatory, urinary and digestive systems; protein metabolism; and the special problems of the elderly patient when subjected to burns therapy. It is of great importance to establish the patient's general pre-burn condition. The anamnesis should assess the degree of functionality of the main organs and systems in relation to the patient's quality of life, the amount of physical activity usually taken, the type of diet, and the sleeping-waking pattern. The possible chronic pathologies that should be investigated are indicated. The three major aspects of intensive care in the elderly burn patient are considered: the choice of infusion fluids, the rate of administration, and the monitoring of the response.

The number of persons aged 65 years and over has considerably increased in the last few years and is at present increasing still faster. It has been calculated that the phenomenon is most marked in the over-70-year-old age group.
Increasing age leads to an increase in the likelihood of being involved in burns accidents. This risk increases due to behavioural disturbances such as those secondary to Alzheimer's disease and other forms of dementia, and to other conditions typical of advanced age.
In the burn patient, age is a highly determinant additional factor that may cause death. This is due to:

1. a progressive involution of the physiological functions of the various organs and systems
2. the onset of chronological pathological conditions
3. the organism's reduced capacity to react to the the~ rapies initiated

A precise assessment of these three aspects is fundanental for the choice of the correct form of intensive care :o be used in the case of the burned elderly patient.
In order to give a more uniform approach to this probem, "elderly" is defined as over the age of 65 years, i.e. .efirement age,

In elderly persons the skin tends progressively to become trophic, dry, wrinkled, loose, and less elastic. The dermic layer becomes thinner, there is a loss of elastic fibres and in general there is a reduction of subcutaneous adipose tissue.
As a result, the skin's function as a protective barrier is impaired. This leads to greater absorption of heat, so that a moderate heat source, e.g. warm water, electric cushions or blankets, and radiators, can cause even serious physical damage. As a result also of the reduced microcirculatory network, thermoregulation is compromised, with increased probability of hypothermia and heat stroke. These alterations in the skin covering assume considerable importance in the assessment of burn severity, especially in the immediate post-burn phase. Thermal damage may appear less serious than it really

Respiratory System
Aging determines a series of modifications in the following:
Thorax, with involvement of

• the costovertebral and muscular structure with
• reduction of thoracic elasticity and
• reduction of ventilatory compliance (reduction of vital capacity; increase of residual volume: increase of functional dead space)

Bronchi and lungs, which present

• reduction of bronchial calibre
• progressive atrophy of the bronchial mucosa with
• reduction of ciliary activity
• distension of the apical alveoli
• reduction of alveolar surfactant
• different distribution of blood flow with consequent reduction in the cough reflex
• tendency to hypoxia
• accumulation of secretions
• increase of stasis infections

Immobilization in bed, even for just 24-72, hours tends to accentuate the reduced functioning of the respiratory system, with the onset of fully developed conditions of bronchopulmonary pathologies due to stasis or infection.

Cardiovascular System
The process of aging involves:

• reduction of cardiovascular function
• reduction of maximal aerobic capacity (V02 max maximum consumption oxygen)
• reduction of cardiac muscle blood flow due to the reduced muscular mass and to the reduction of blood flow caused by a reduction in ventricular compliance due to the rigidity of the cardiac muscle (caused by an increase in the connective portion and to structural modifications of the contractile proteins)
• reduction of the cardiac and vascular response to beta-adrenergic stimulation with
• reduction of basal heart rate
• reduction of the functional reserve capacity of the cardiovascular system in moments of stress, effort, and postural changes
• modifications of pressure values with a tendency towards hypertension due to
• modifications of vascular capacitance secondary to thickening of the intima and the media, increase of collagen and calcium of the clastica and the glucosaminoglycans, increase of intimal cellularity and of lipids in the external tunica, leading eventually to a sodium-dependent hypertrophy of the museular cells of the media. This is associated with a modification of the sino-aortic baroceptive response to the increase in pressure values, which triggers increased activity of the nervous sympathetic system, with the release into the circulation of a greater quantity of noradrenaline. This, together with the beta-adrenergic down-regulation which occurs at cardiovascular level, contributes to the greater increase of the peripheral vascular resistances because they facilitate the incorporation of amino acids in the proteins of the vascular structures and thus cause thickening of the walls

If the elderly burn patient has riot led an active physical life and is subject to long-term immobilization, the above picture is aggravated because the following aspects are augmented:

• reduction of the organism's energy consumption
• reduction of metabolic requirements in the first days (this may however be an advantage)

Subsequently the following may be observed:

• increase in heart rate (caused by a diversion of the blood flow towards the splanchnic district and also due to a reduction in the vis a tergo determined by the cardiac muscle) failure of cardiac function to adapt to the requirements, though reduced, with a possibility of ischaemic conditions visible on ECG presence of ischaemic-type disturbances caused also by the reduction of K and Mg as a result of immobilization
• onset of venous thromboses (often with pulmonary thromboembolism) due to slowing down of blood flow, compression of the venous wall against the base, diversion of blood towards the splanchnic system, and a tendency towards alteration of the coagulation/fibrinolysis balance

Urinary System
After the third/fourth decade of life the following processes gradually begin:

• reduction of renal mass
• modification of intrarenal vascularization
• quantitative reduction of glomerules and tubules with
• reduction of renal plasma flow and glomerular filtration. The glomerular filtrate and tubular mass reduce by about 6% every 10 years and at the age of 65 years glomerular filtration is reduced by one-third
• reduction in clearance of endogenous creatinine (1 ml/min/yr) reduction in urinary excretion of creatinine (due to reduction of the muscular mass), for which reason a constant creatinaemia value is observed despite the progressive reduction in clearance`

In the event of prolonged immobilization we observe:

• marked reduction in creatinine clearance secondary to reduced muscular production and reduced endogenous creatinine
• urinary retention because the calices adopt a vertical course with an upward flow direction, due to horizontalization of the ureters and the difficulty of emptying the bladder (patients find it difficult to urinate in bed)
• urinary infections and urolithiasis due to an increase in calcinuria and modifications in urine Ph caused by immobilization"

Digestive System
The process of aging affects the digestive systems in a number of ways:

• This thesis is supported by studies on acute post-burn organ failure which have shown a clear relationship between advanced age and the probability of the development of acute organ failure and therefore death. The situation deteriorates further in the case of elderly persons who take little physical exercise or worse still if compelled to stay in bed, even if only for a few days. Geriatric specialists confirm that in these conditions important metabolic alterations occur which must be con
• reduction of secretory and motor function (lazy sidered carefully in the elderly bum patient. intestine)
• anorexia due to reduction of energy consumption, which leads to early reduction of appetite and even a sense of repugnance towards food; some drugs, e.g. digitalis, may also be responsible for anorexia
• stipsis due to reduced food intake and food quality (semiliquid foods without roughage are often preferred), reduced physical activity, hypotonia of the prelum abdominale caused by electrolytic alterations, especially in potassium
• confusional state, due also to the condition of hyper ammonaemia caused by the stasis of facces in the colon
• scatomas due to dehydration of the facces
• faecal incontinence due to scatomas which irritate the colon mucosa, producing mucus. At the same time the putrefactive microbic fauna attacks and liquefies recent faecal mass, producing semiliquid material which slips along the walls and exits in the form of alvine mucose discharges alteration of hepatic function due to
• reduced liver mass
• reduced blood flow
• reduced efficiency of the microsomial oxidation system
• reduced enzymatic activity

Physiological Functions - Physiological Reserves
The deficiencies of these functions do not always reach a clinical threshold but may become evident as soon as there are conditions of stress.
In such conditions the appearance of deficiencies is favoured by a reduction in the neuroendocrine response, which is related to a drop in the concentration of hormones and hormone receptors in the general context of physiological and endocrinal decay due to aging. The decrease of visceral functions is more marked as age advances. When an elderly person suffers a burn the Jecrease becomes a factor provoking death, and is there fore an indirect index of metabolic efficiency.

1. Glucose metabolism

The process of aging produces a reduced tolerance of glucose, starting in the third decade of life. The effects of age on glucose metabolism are evident in the altered response to tests with orally administered glucose which have shown a mean increase in glycaemia of about 6-13 mg/dI for every decade of life one to two hours after administration.

The causes of this phenomenon include the following: a glucose-induced delay in secretion of insulin; a delay in the insulin-induced inhibition of hepatic glucose output; an alteration of the peripheral utilization of glucose in insulindependent tissues (mainly musculoskeletal); and an alteration of the utilization of glucose in non insulin-dependent tissues (mainly CNS)."

After 24-72 hours of complete immobilization in bed, even in young persons, there is a significant reduction in the peripheral uptake of glucose caused by insulin resistance, as testified by the increase in insuliDaemia levels and by the lower reduction in glycaemic levels after administration of exogenous insulin.

One of the causes of this condition is the lack of physical activity, which undoubtedly has an insulin-like function or at least a functional synergism with the action of insulin.

2. Protein metabolism

Elderly persons present a state of:

• hypoproteinaemia, favoured by poor feeding, digestive disturbances and any renal malfunction
• hypopotassiaemia, favoured by an inappropriate diet, insufficient muscular activity, and insufficient renal function
• hypomagnesia, due to nutritive deficiencies
• hypernatraemia and hyperosmolarity, due to dehydration, hypopotassiaernia, and insufficient renal function

Reduced muscular activity and immobility cause an increase in the urinary elimination of nitrogen, potassium, phosphorus and calcium, causing further deterioration of the above deficits.

1. Fat metabolism

Reduced physical activity in the elderly determines a significant increase in total lipaemia, cholesterolaemia and the beta-alpha lipoprotein ratio.

Given the above considerations, in the intensive care of the elderly burn patient the following are of particular importance:

• a hypothetical assessment of the patient's pre-burn conditions as a function both of age and of possible acute pathological episodes
• an assessment of the seriousness of chronic pathological conditions present on admission to hospital

Only an accurate anannesis, involving family members if necessary, can make it possible to establish the patient's general pre-burn conditions.

The anamnesis will attempt to assess the degree of functionality of the main organs and systems in relation to the quality of life led by the patient, the amount of physical activity taken, the type of diet, the sleeping-waking pattern, etc.

An investigation will also be made with regard to any pathological episodes in the following:

• respiratory system: bronchopulmonary episodes and their frequency, pulmonary embolisms, etc.
• cardiovascular system: episodes of coronary failure, hypertension, and cerebrovascular incidents
• urogenital system: infections of the urinary tract and their frequency
• previous surgical operations
• long-term pharmacological treatment

The possible chronic pathologies to be identified on admission include:

• diseases of the metabolism: diabetes, uricaernia, hypercholesterolaernia
• tabacosis, alcoholism, addiction to narcotics
• chronicized allergies to drugs and foods
• respiratory pathologies: chronic bronchitis, asthmatic bronchitis, bronchiectasis, etc.
• cardiocirculatory pathologies: hypertension stabilized around values of 160/100, dilatative ischaernic cardiopathies with anginoid episodes, terations in rate and conduction, cerebral and arteriosclerotic vasculopathies, venous pathologies, etc.
• pathologies of the genitourinary system: chronic renal failure, dialysis, urinary infections due to prostate hypertrophy, urolithiasis haernatic pathologies: haemocoagulation alterations whether primary or secondary to pharmacological treatment, anaemia, etc.
• pathologies of the digestive system: chronic diarrhoea, stipsis, spastic colitis, hepatic failure, bile stones, cirrhosis, etc.
• neuropsychiatric pathologies: epilepsy, Parkinson's disease, depressive neurosis, psychosis, etc.
• pathologies of the skin, muscles or skeleton: ulcers, pressure sores, necrosis, arthropathies, etc.
• isolated or metastatic neoplastic pathologies
• multiple pathologies involving one or more organs

In burns there is no doubt that the manner of administering therapy, especially in the acute phase, will condition prognosis. As already said, the elderly patient has reduced cardiovascular responses and reserves that are compromised by age, for which reason fluid therapy in intensive care can itself be risky.

Thus a burn of fairly limited extent and with a normal~ ly favourable prognosis can become lethal if it determines an overload of liquids, not simply on its own account but because of the specific cardiocirculatory system and in the antidiuretic phase of shock.

It therefore follows that in the elderly burn patient the rate of fluid administration must have different characteristics from those normally observed.

At this point we may consider another important aspect in the treatment of the elderly burn patient: that of clinical pharmacology.'

In the elderly there are a number of pharmacokinetic modifications at the following levels:

1. phase of absorption. This is modified only in part but significantly
2. phase of distribution. Owing to the reduction of the lean mass, hydric pool, systemic flow and portal flow, this determines:

• increased distribution of liposoluble drugs
• reduced distribution of hydrosoluble drugs
• increase in the free concentration of acid drugs
• reduction in the concentration of basic drugs

1. phase of elimination reduction in drug elimination rate due to the reduced cardiac output and reduced renal vascularization, with consequent reduced plasma flow and glomerular filtration

This involves a risk of: toxicity, in the case of drugs with a limited therapeutic range, e.g. digoxin, chinidine, aminoglycols, etc.

accumulation, in the case of drugs such as penicillin, procainamide, etc.

On the basis of the above remarks three aspects appear to be of major importance:

• choice of infusion fluids
• rate of administration
• monitoring of response

Infusion fluids

Intensive care in the acute burn phase is principally concerned with the control of oedema. The increase of oedema is affected by the quality and quantity of fluids infused.

On the basis of the assumption that the elderly patient presents a basic hypoproteinaemia, an often precarious hydroclectrolytic balance, and imperfectly efficient cardiocirculatory, respiratory and renal functions, the use of colloid solutions is the most indicated choice in intensive-care.

The advantages which colloid solutions determine as regards cardiac output, vascular and pulmonary resistance and the control of organ and general oedema make it possible, with a smaller quantity of fluid, to restore the circulating volume, tissue perfusion and good haemodynan-ric stability.

Experience gained in the treatment of 126 elderly patients with bums in 15 to 60% BSA enables us to make the following considerations:

• elderly patients require a differentiated care protocol
• the use of fixed formulae to calculate the quantity of fluid to infuse is scarcely compatible with the realistic approach of guided therapy

• the rate of administration is not regulated in terms of fixed time (e.g. half quantity in first 8 hours, etc.) but must depend on a constant assessment of the clinical picture and laboratory findings" (Fig. 1)

Fig. 1 Fig. 2 Fig. 3

Monitoring of response

Monitoring of the functions of the various organs and systems must be as comprehensive as possible, starting from the moment of admission, before initiating fluid therapy, in order to assess the "actual state" of the patient and thus to obtain "the basis on which to operate" (Fig. 2). Monitoring must continue regularly throughout the course of treatment (Fig. 3).
On admission the clinical data and laboratory tests indicated in the slide must be performed. The pattern of administration used in the first 24 hours is shown.
Monitoring during fluid therapy in intensive care is articulated in various time intervals: 48 hours and 72 hours (Fig. 4).

Fig. 4

Conclusions

The most dangerous phase in the treatment of the elderly burn patient is undoubtedly the shock phase.
Intensive care is a delicate moment during which it is difficult to achieve a correct balance between the patient's resuscitatory requirements determined by the state of hypovolaemic shock and the capacity of the aged organism to respond.
Fluid therapy must be limited, using only sufficient quantities of fluid strictly necessary to maintain a good clinical response.The quantity to be administered depends on the clinical response and on laboratory findings.Generally speaking, as the fluid requirements in most patients are only moderate, they should receive a sufficient amount of fluid, if possible in part orally and in part venously, to maintain adequate tissue perfusion.While the best way of measuring the adequacy of intensive care may still be controversial, it should be remembered that changes in central venous pressure, for example, prove more useful if followed up rather than being taken as a sign of the beginning of pulmonary oedema. The changes are unreliable as an indicator of fluid overload in the acute phase.All progress made in reducing the post-bum death rate in the elderly is the result of a reduction in iatrogenic complications and to new therapeutic measures. This confirms the difficulty of producing a standardized intensive care protocol.

RESUME. L'âge avancé est un facteur déterminant qui peut causer la mort des patients brûlés, à cause de l'involution progressive des fonctions physiologiques des divers organes et systèmes, de l'instauration de conditions pathologiques chronologiques, et de la capacité réduite de l'organisme de réagir à la thérapie. Les auteurs analysent ces trois facteurs en détail par rapport à la peau et aux systèmes respiratoire, cardiocirculatoire, urinaire et digestif; au métabolisme protéique; et aux problèmes particuliers du patient âgé soumis à la thérapie des brûlures. Il est très important d'établir les conditions générales du patient avant l'accident. L'anamnèse doit évaluer le degré de fonctionnalité des organes et systèmes principaux par rapport à la qualité de vie du patient, à la quantité d'activité physique quotidienne, aux habitudes alimentaires, et au rythme veille/sommeil. Les pathologies chroniques possibles qu'il faut chercher sont indiquées. Les auteurs concluent en considérant les trois aspects plus importants de la réanimation du patient âgé brûlé: le choix des fluides d'infusion, le rythme d'administration, et le monitorage de la réponse.

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This paper was received on 4 April 1995, and presented at the Round Table on "Consideration on Reanimation Therapy in Elderly Burn Patients" at the 6th EBA Congress in Verona, 13 - 15 Sept. 1995. Address correspondence to: Prof. Michele Masellis M.D., Divisione di Chirurgia Plastica e Terapia delle Ustioni, Ospedale Civico, Via C. Lazzaro, 90127, Palermo, Italy.

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