Golden Years - Anaesthesiaand Nursing Care of Geriatric Patient

GOLDEN YEARS - ANAESTHESIAAND NURSING CARE OF GERIATRIC PATIENT

Louise O’Dwyer

MBA BSc(Hons) VTS(Anesthesia&ECC) DipAVN(Medical & Surgical) RVN

Clinical Support Manager, VetsNow, Manchester, UK

The continued advancement of medical knowledge manifested in the availability of more sophisticated diagnostic testing, advances in specialised nutrition, and newer therapeutic options, along with education regarding early warning signs of disease and routine screening for age-related disease has better positioned veterinary professionals to treat age-related problems and provide the high-quality health care these owners are demanding. These factors have led to practices having more elderly patients admitted into their care. Veterinary nurses readily advise clients about the additional needs of elderly animals at home, however they must be careful not to neglect to apply such recommendations to these same animals when they are admitted into the practice and are under their care.

Elderly patients may be diagnosed with various and often multiple conditions which may require medical and/or surgical management. Elderly patients must be treated with extra care; they are less able to adapt to change and they recover more slowly from medical or surgical interference

Admission of the Geriatric Patient

Comprehensive histories are especially critical in senior medicine. Detailed information including decrease or increase in food or water consumption, alterations in bodyweight or activity level and behavioural changes are all important pieces of information. Owners are in a unique position to note subtle changes in daily routine, but may not offer such information unless prompted.

It must be remembered that patients may be suffering from diseases other than those for which they have been admitted so concurrent disease and medications must be ascertained. On a busy ward it is easy for veterinary surgeons and nurses to become enthusiastic about treating a particular condition, only to overlook the fact that the patient is also supposed to be receiving medication for a cardiac condition, a prescription diet for chronic renal disease, eye drops for keratoconjunctivitis sicca, etc.

Sensory Impairment

Some degree of visual or auditory impairment is likely to be present in ageing animals and while such animals may function quite normally in a protected environment such as the home, the unfamiliar and confusing surroundings of a veterinary practice may lead to nervousness or signs of aggression.

Cardiovascular

The cardiovascular system accounts for many alterations due to age related changes or age related disease. Symptoms may be absent with gradual, age related, deconditioning changes; or symptoms may be acute in a sudden decompensation. The vasculature of aging patients gradually loses elasticity, due to deposits of abnormal collagen, resulting in decreased vascular capacity and increased peripheral resistance to cardiac output. Nursing care of the geriatric patient should always include heart and pulse rate assessment, digital palpation of distal pulses, capillary refill time assessment, auscultation of heart sounds, serial measurements of blood pressure using oscillometric, Doppler, or direct arterial catheter methods.

Respiratory

Age related conditions of the respiratory system include upper airway and lower airway changes. Progressive changes of the upper airway system include a decrease in airway protective mechanisms (laryngeal function), a decreased cough reflex, and an increase in pulmonary secretion viscosity. Lower airway ventilatory changes in the geriatric patient decrease the efficiency of gas exchange. Wasting of the diaphragm and intercostal muscles decreases total lung expansion (tidal volumes-VT) within the thorax. Alveoli decrease in number and elasticity as age increases. These parenchymal changes of the lung can resemble emphysema with a decreased alveolar diffusion function and the appearance of fibrotic or atelectic areas. Nursing care procedures should begin with careful evaluation of respiratory rate, depth, and pattern. Any changes should be examined to identify a potential cause and possible correction. Lung sounds should be monitored every four hours. Also important to respiratory health are simple procedures such as humidifying supplemental oxygen, rotating patient positioning, and active walking whenever possible. These preventive measures can protect fragile airway tissues, prevent lung tissue atelectasis, and increase expectoration of respiratory secretions. If possible, patient positioning should be changed every two hours or at minimum every four hours. All patients should be encouraged to walk as much as is appropriate for their individual condition.

Gastrointestinal System

Elderly patients are less able to tolerate periods of inappetence. Although lower exercise levels and a reduced metabolism will result in some degree of inappetence, in any elderly patient is a cause for concern and needs to be addressed — even in apparently obese patients. Details of type of food, amounts offered and consumed along with a body condition score and weight should be recorded daily on all patients’ hospitalisation sheets. Because of the high variability in the effects of age on dogs and cats, feeding management of the ageing pet must be highly individualised. A thorough assessment of the usual diet and feeding practices is required and a patient’s individual daily energy requirement should be calculated on the basis of their bodyweight, age and disease. It is beyond the scope of these notes to discuss senior nutritional requirements, however as a general rule a highly digestible diet is necessary as digestion is generally less efficient in ageing animals due to reduced liver function and gastrointestinal absorption and motility. Elderly animals have a decreased thirst response. This means they are susceptible to dehydration with illness or during hospitalisation. Such dehydration can obviously compromise already marginally functioning body organs and compound deficiencies in renal function. Increasing the fluid content of food can help to prevent dehydration in patients who may not ingest sufficient fluid for their daily metabolic requirements. There is an increased incidence of constipation in elderly pets, which may also be alleviated by increasing the fluid content of their food (may require medication also). Constipation can be very uncomfortable for a patient thus they are less likely to eat and may also vomit thereby potentially exacerbating other conditions. Fresh water must always be available and fluid input, urine production and hydration status must be monitored closely.

Renal

Renal insufficiency and/or disease are common conditions affecting the health of a geriatric patient. Loss of cortical mass (kidney size and weight), decreasing numbers of functioning glomeruli, decreasing size of renal tubules, and an increase in tissue fibrosis are common findings in aging pets. The kidney's distal tubules also become less responsive to the renin-angiotensin system, decreasing a patient's ability to conserve sodium and water. Morphologic changes like these result in decreasing renal blood flow, glomerular filtration rate, and ability to concentrate urine. All of these alterations make a geriatric patient much less tolerant of a decrease in body water status.

Hepatic system

The overall mass of the liver decreases with increasing age due to decreasing number and function of hepatocytes (liver mass), leading to a decrease in overall hepatic function, including drug clearance. A decrease in hepatic function causes an increase in the plasma half-life of drugs which are dependent on hepatic metabolism or excretion. The veterinary surgeon will base their choice of therapeutic agent on a risk:benefit analysis which generally cannot be performed without a thorough evaluation and health screening of the patient. It is worth remembering that the ageing process continues throughout life, therefore patients on long-term medications require regular monitoring to reassess their status and drug doses or frequency may need to be adjusted accordingly.

Urinary system

Many elderly patients will be suffering from varying degrees of renal compromise and may drink and urinate in excess of normal calculated volumes. This results in many elderly patients being polyuric or incontinent, thus special consideration should be given to choice of bedding material provided, along with toilet facilities and opportunities for elimination. Urine-contaminated bedding must be changed quickly and urine-contaminated fur washed and carefully dried. Clipping of hair around the genital region may be required, especially in longer coated breeds, along with the application of a barrier cream to help prevent urine scalds. Elderly animals can become fussier with age so it is important to elicit the essential information regarding toilet habits from the owner — what type of cat litter is preferred, does the dog prefer to eliminate on grass or concrete, will it only toilet in response to a particular command? Such foibles are more common in elderly animals which tend to be resistant to change.

Musculoskeletal system

Within the musculoskeletal system many physical changes become apparent as time passes, a number of which can be profound. Osteoarthritis is the term given to a progressive, irreversible joint disease associated with cartilage degeneration, modification of subchondral bone, development of osteophytes, synovitis and fibrosis of the joint capsule. There is often a gradual loss of muscle mass in the ageing animal, leading to a degree of muscle weakness, most profoundly in the limbs. Such musculoskeletal changes make it difficult for animals to mobilise on smooth or slippery surfaces. While veterinary nurses frequently advise clients regarding modification of the home environment, it is essential not to overlook similar aspects within the hospital environment. Use of non-slip mats should therefore be considered on slippery surfaces where necessary. Rubber mats from consulting tables are a good substitute where specific floor mats are not available. Elderly dogs enjoy ‘pottering’ and even hospitalised dogs should be allowed time to wander, maybe in an outdoor run. Frequent short walks will help to exercise stiff joints and ensure plenty of opportunities for elimination, and enhance the wellbeing of the patient. Elderly cats often spend long periods of time sleeping, however encouraging them to move around can be beneficial to circulation and joint health. A quiet consulting room can often be utilised for this purpose. Animals with reduced mobility, loss of muscle mass and osteoarthritis often prefer to stay in one position, increasing their risk of developing a decubitus ulcer on prominent bony areas. Relief of pressure via the padding of bony prominences and use of memory foam mattresses along with vigilant monitoring and the implementation of a detailed nursing care plan should help avoid this. Veterinary nurses and technicians should ensure that gentle handling and the minimum possible restraint is applied during examination and venepuncture. As joint degeneration and muscle atrophy are common amongst ageing patients, restraint may well be painful for affected individuals. Physiotherapy may be of benefit here and veterinary nurses/technicians can perform a number of physiotherapy techniques under the direction of a veterinary surgeon. Basic techniques including massage, effleurage (gentle stroking of the limbs towards the heart) and passive joint movement, if carried out correctly and regularly, can improve circulation, maintain and increase joint mobility, decrease pain, promote muscle relaxation, aid in the healing process and prevent stiffness.

Cognitive function

Geriatric pets display an increased incidence of cognitive dysfunction, which is an impairment of sensory transmission and processing. There is a reported decrease of visual acuity, hearing, memory, learning perception, and general awareness in geriatric pets. These patients may react more fearfully or aggressively toward novel stimuli. Separation anxiety is present in an estimated one third of all geriatric dogs, followed closely by aggression and house soiling. In cats, diminished social interaction, progressing to aimless wandering or activity, and excessive vocalization are common with advanced age. Startling responses such as aggression occur commonly, and technicians should be cautious with patients that may be disoriented, deaf, or blind.

Thermoregulation

Normal thermoregulatory mechanisms are controlled by the hypothalamus, which initiates vvasomotor or metabolic responses to maintain core body temperature within a narrow range, despite widely varying environmental temperatures. Ageing animals have decreased thermoregulatory capacity thus may be more heat or cold seeking dependent on the season and the ambient temperature. Regular monitoring of body and environmental temperatures is therefore essential and appropriate and safe forms of heat or cooling systems should be utilised accordingly

Tender loving care

While it is certainly not acceptable, it is perhaps understandable that in a busy veterinary practice, the ‘tender loving care’ aspect of nursing is sometimes overlooked. However, despite staff and time limitations, this is undoubtedly one of the most important aspects of nursing care. As discussed, elderly inpatients are often frightened and confused so need that little bit of extra care more than ever; these patients really do need, and benefit greatly from, a little bit of extra care and attention compared with younger patients. Remember elderly patients are generally the patients that are less able to compensate for any shortfall in nursing care; that little bit of extra attention might just help identify why the patient is withdrawn, inappetent etc.

ANAESTHESIA CONSIDERATIONS

It has been suggested that around 30% of the veterinary population is geriatric. Many of these animals will require anaesthesia for dental care, diagnostic or surgical procedures. There is a wide species and breed variation in lifespan, therefore there is not one specific age which can define ‘geriatric’. Instead, the term is normally used to define those animals who have reached 75-80% of their expected lifespan. Factors influencing the ageing process include breed, size, genetics, nutrition and environment.

Physiology

Ageing causes a progressive and irreversible decrease in functional reserves of the major organ systems, leading to altered responses to stressors and anaesthetic drugs. Changes in the organ system function may be covert until the patient is stressed by an illness, hospital stay or general anaesthetic procedure.

Pharmacology

The pharmacokinetic and pharmacodynamics properties of sedative and anaesthetic drugs change with age. Due to the changes in the central nervous system, geriatric animals have a decreased requirement for many drugs. Reduction in cardiac output means induction agents and boluses of injectable drugs take longer to exert an effect consequently it is easy to overdose.

Pre-Operative Assessment

Individual geriatric animals require different anaesthetic protocols depending on their concurrent illness, temperament, reason for anaesthesia and clinical exam. A complete history should be taken, paying particular attention to previous and current medical complaints and current medications. Discussion should be made with the veterinary surgeon as to the effect that concurrent medications may have on the patient under anaesthesia and the protocol adjusted accordingly. A full clinical examination should also be performed along with relevant diagnostic testing.

Drug / Properties / Relevance to Geriatrics / Precaution
Acepromazine / Anxiolysis sedation, long duration of action, not reversible, hypotension by vasodilation, hepatic metabolism / sedation, recovery time, hypothermia, possible hypotension / Monitor blood pressure, use lower doses, avoid in cases of dehydration, liver dysfunction, coagulopathy or haemorrhage
Benzodiazepines / Anxiolysis, sedation, minimal cardiovascular effects, short acting, can cause excitement in some animals, hepatic metabolism / Can be reversed with flumazenil, minimal cardiovascular effects make them useful in geriatrics
Full opioid agonists / Excellent analgesia, mild sedation, mild cardiovascular effects, dose-dependent bradycardia / sedation, analgesia, minimal cardiovascular effects make them useful in geriatrics. / Titrate dose to effect in sick geriatrics, effects can be reversed with naloxone
Partial opioid agonists / Minimal cardiovascular effects, less sedation than full opioids, good analgesia for mild to moderate pain, long acting
Mixed opioid agonist- antagonist (butorphanol) / Good sedation, minimal cardiovascular effects, poor analgesic / Minimal cardiovascular effects make it useful for geriatric sedation for non-painful procedures
Alpha-2- agonists / Profound cardiovascular effects: vasoconstriction and ⇓cardiac output, profound sedation, short acting, action, can be reversed / Profound decrease in cardiac output / Use with caution, only healthy geriatrics, especially avoid in patients with heart or cardiovascular disease

Table 1

Premedication

Pre-anaesthetic medication is useful to reduce anxiety and to facilitate IV catheter placement. his may be of particular importance in geriatric patients who are more prone to stress. Premedication also contributes to a balanced anaesthetic technique, reduces the amount of anaesthetic agents required and provides analgesia, all of which are beneficial in the geriatric patient, however careful drug and dose selection will be required, especially in those with underlying conditions. Commonly used premedicants are listed in Table 1.

Induction

Pre-oxygenation should be performed for 5 minutes using a tight-fitting mask, however if the patient is intolerant, then a flow-by technique, or mask with the diaphragm removed can be used. The specific IV induction agent used appears to be less important than the way it is administered. increased age may reduce the amount of induction agent required and the reduced cardiac output will increase the time taken for the drug to exert an effect. Therefore, it is important to administer induction agents slowly to effect in geriatric patients, and an IV catheter greatly aids this. A co-induction agent with minimal cardiovascular effects such as midazolam or fentanyl could be considered to reduce the amount of induction agent required and there- fore the side effects, however only fentanyl has been demonstrated to reduce the dose of propofol required. Mask inductions are not generally recommended in geriatric patients, due to the stress they cause. Induction and maintenance of anaesthesia with inhalant anaesthetics alone in dogs was associated with a 5.9 times increase in the likelihood of anaesthetic-related death.

Patient positioning