Anesthetic Consideration for Geriatric Patients

*Somchai Amornyotin*

### **Abstract**

The geriatric population experiences significant alterations of numerous organ systems as a result of the aging process. They also have several co-morbidities including hypertension, cardiac disease, diabetes, cerebrovascular disease and renal dysfunction. Geriatric patients are considerably vulnerable and especially sensitive to the stress of trauma, surgery and anesthesia. A high incidence of postoperative complications in this population is observed. Appropriate perioperative care was required for geriatric patients. To date, development in anesthesia and surgical techniques has substantially reduced morbidity and mortality in the geriatric patients. Several anesthetic techniques have been utilized for these patients. However, anesthesia-related mortality in geriatric patients is quiet high. All geriatric patients undergoing surgical procedures require a preprocedural evaluation and preparation, monitoring patients during intraprocedural and postprocedural periods as well as postprocedural management. This chapter highlights the physiological changes, preprocedure assessment and preparation, anesthetic techniques, intraprocedural and postprocedural management in geriatric population.

**Keywords:** anesthesia, analgesia, geriatric, elderly, management

#### **1. Introduction**

The geriatric population is quickly growing and living longer, and this development is estimated to significantly increase surgical demand for both elective and emergent cases. Normally, functional reserve and organ functions are declined in the geriatric patients. Perioperative management of geriatric patients is clearly different and commonly more complex than in younger patients. The consequence of surgery and anesthesia in geriatric patients is directly related to the care they receive during the perioperative practice. However, morbidity and mortality rates after surgery in the geriatric patients are significantly higher than the younger patients. Furthermore, inhospital adverse events and prolonged duration of hospital stay are frequently observed in these patients [1, 2]. Although, age itself is not a disease process but instead serves as a chance for developing age-related diseases. The adverse events could be lessened by appropriate preoperative assessment, proper anesthetic technique and careful postoperative management.

#### **2. Cardiovascular system**

Physiologic changes of the vascular system include atherosclerosis and increased arterial wall thickness. In addition, aging leads to decrements in the extent of

autonomic control of the cardiovascular system. Aging patients have a reduced cardiac output. Systolic function could be remarkably conserved. However, cardiac responsiveness to adrenergic stimulation is declined. Maximal heart rate and cardiac output also decrease with age [3]. Consequently, baroreflex responses could not completely maintain hemodynamic stability in stressful conditions such as orthostatic hypotension and administration of vasoactive drugs. The functional capability of organs declines and co-existing diseases further contribute to this deterioration. Ischemic heart disease, hypertension, diabetes mellitus and hypercholesterolemia are common in the geriatric patients. Subsequently, autoregulation of blood flow to kidney and brain is reduced. The physiological stress response may be impaired because of decreased autonomic function. The cardiac muscle hypertrophy that develops secondary to the increased late systolic afterload leads to myocardial thickening and diastolic dysfunction. Atrial fibrillation is also common in the geriatric patients. Importantly, age changes both pharmacokinetic and pharmacodynamic aspects of anesthetic agents. Response to induction agents results in exaggerated effect on blood pressure. There is also a reduced response to atropine. Moreover, diminished responses to hypovolemia are supplementary confounded by volatile anesthetics and the sedative drugs that impair baroreflex control mechanisms [1, 3].

## **3. Respiratory system**

Functional capacities of the respiratory system are all reduced in the geriatric patients. Decrease in chest wall compliance and the strength of respiratory muscles, making the lungs more difficult to ventilate and declining in maximum inpiratory and expiratory force. Increased alveolar compliance with collapse of small airways and subsequent alveolar hypoventilation, air trapping leading to ventilation perfusion mismatch. Additionally, collapse of small airways, consequent alveolar hypoventilation, and air trapping may lead to ventilation perfusion mismatch. The residual volume is also increased. Ventilatory response to hypoxemia and hypercapnia are deteriorated in the geriatric patients. Hypoxemia can develop easily. Moreover, the prevalence of chronic obstructive pulmonary disease intensely increases with age [4]. Atelectasis and pulmonary infections are more common in these patients. Administration of premedication could increase the patient's risk for aspiration. Combination of residual effects of anesthetic agents, prolonged effect of neuromuscular blocking drugs and postoperative pain, could significantly contribute to the respiratory complications.

## **4. Renal system**

Aging is accompanying with a steady deterioration in renal function. Reduction of glomerular filtration rate, capability to concentrate urine, and reservation of renal function are noted. Monitoring of urine output during and after major surgery would be regularly performed. Geriatric patients do not require a specific fluid regimen. However, they are less able to achieve hypovolemia or hypervolemia. Though, postoperative renal failure is rare, reduced renal blood flow and decreased nephron mass may increase the risk [5]. Risk factors for acute postoperative renal failure include advanced age, diabetes mellitus, preexisting renal insufficiency, major vascular surgery, and recent exposure to nephrotoxins. Sympathetic stimulation, pain, surgical stress, and the use of vasoconstrictive drugs may induce subclinical renal insufficiency.
