Anesthesia for the geriatric patient
Geriatrics/geriatric patient refers to medical care for older adults, an age group that is not easy to define precisely. “Older” is preferred over “elderly,” but both are equally imprecise; > 65 is the age often used, but most people do not need geriatrics expertise in their care until age 70, 75, or even 80.
The geriatric patient 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. 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.
Diminished cardiac reserve in elderly patients often manifests as exaggerated drops in blood pressure during induction of general anesthesia (GA). Reductions in the responsiveness of beta-receptors caused by a beta-blocked state limits patients’ ability to increase cardiac output and properly respond to blood losses. Baroreceptor dysfunction and reduced responsiveness to angiotensin II further limit responsiveness to hypovolemia. All these factors may be compounded by comorbid myocardial ischemia related to atherosclerosis.
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 inspiratory 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
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.
Pulmonary function declines with age due to loss of both lung and chest wall compliance and oxygen diffusion capacity, especially in smokers, contributing to decline in oxygen uptake and delivery. Age and functional dependence have been identified as the most reliable risk factors for postoperative pulmonary complications (PPC).