Module: 6 Geriatric

Patients aged 65 years or older are classified as geriatric or elderly.
Importance of tools to measure functional reserve and identify perioperative risks.
- Metabolic Equivalents (METs):
- One MET equals the oxygen consumption of 3.5 mL O2/kg/min.
- Inability to achieve 4 METs associated with increased perioperative risk.
- Activities meeting 4 METs include climbing a flight of stairs without stopping and raking leaves.
- Limitations of METs:
- Subjective nature makes it a poor predictor of postoperative morbidity and mortality.
- Duke Activity Status Index (DASI) may be a better tool for assessing functional status.
Frailty:
- Defined as decreased physiological reserve coupled with reduced resistance to stress (physiological, physical, psychosocial).
- Frail patients are more likely to experience poor outcomes under perioperative stressors.
Example of oxygen consumption in a 70-kg patient walking upstairs:
- Consumed oxygen during activity can be calculated using METs.

By 2050, individuals over 60 will outnumber younger adults for the first time.
Increased exposure to geriatric patients expected in healthcare.
Terms geriatric and elderly are used interchangeably, both referring to those 65 and older.

Males:
- 1960: 66.8 years
- 1980: 71.5 years
- 2000: 75.8 years
- 2010: 77.7 years
- 2030: 79.5 years
- 2050: 80.8 years
Females:
- 1960: 73.5 years
- 1980: 78.4 years
- 2000: 80.6 years
- 2010: 84.3 years
- 2030: 85.8 years
Physiologic Changes:
- Physiologic function may begin to decline as early as age 30.
- Aging significantly increases the risk of cancer development.

Definition:
- MET represents the metabolic rate of specific physical activities compared to resting metabolic rate.
Standard Measurement:
- 1 MET = 3.5 mL O2/kg/min.
Risk Assessment:
- Inability to achieve 4 METs correlates with increased perioperative risk.
- Mortality decreases by 11% for each additional MET achieved.
Questions Indicative of Surgical Fitness:
1. Can you walk up a flight of steps without stopping?
2. Are you able to walk four blocks without stopping?
MET Levels:
- 1 MET = Poor functional capacity
- 4 METS = Good functional capacity
- 10 METS or more = Outstanding functional capacity
Examples of Activities and Corresponding MET Values:
- Self-care activities: 1 to 2 METs
- Working at a computer: 1 to 2 METs
- Walking 2 blocks slowly: 2 METs
- Climbing stairs without stopping: 4 METs
- Raking leaves: 4 METs
- Strenuous sports (running, swimming, basketball): 8 METs
Limitations of METs:
- Subjectivity limits efficacy in predicting postoperative outcomes.
- DASI may be preferred for functional status assessment.

Definition and Importance:
- Frailty indicates decreased reserve and higher vulnerability to stressors.
- Frail patients have poorer outcomes with stressors in perioperative settings.
Research Focus:
- Development of preoperative tools to quantify frailty and identify modifiable risks is critical.
- Potential for preoperative rehabilitation programs to enhance outcomes for frail patients, though literature is still emerging.

Key Respiratory Changes:
- Minute ventilation: Increased
- Lung compliance: Increased
- Lung elasticity: Decreased
- Chest wall compliance: Decreased
- Response to hypercarbia and hypoxia: Decreased
- Protective airway reflexes: Decreased
- Upper airway tone: Decreased
Increased Factors:
- Dead space increases with aging.

Minute Ventilation Effects:
- Increasing dead space necessitates higher minute volume to maintain normal $PaCO2$ levels.
Compliance:
- Defines ease of lung inflation. High compliance means easy to inflate the lungs compared to pressure.
Elasticity:
- Describes the tendency for an inflated lung to revert to its original shape. Loss leads to airway collapse, resulting in:
- Increased dead space
- Decreased alveolar surface area
- Increased ventilation/perfusion (V/Q) mismatch
- Increased alveolar-arterial (A-a) gradient
- Decreased $PaO2$
Altered Lung Volumes & Capacities:
- Aging lung: high compliance and low elasticity lead to gas trapping, increasing residual volume.
Effects on Chest Wall:
- Stiffer chest wall due to calcification and flattened diaphragm leads to reduced expansion tendency.
Increased Work of Breathing:
- Increased respiratory depressant caution necessitated.

Changes in Lung Capacities:
- Closing capacity surpasses functional residual capacity (FRC) at ~45 years supine and ~65 years standing.
- Increased functional residual capacity (FRC), increased closing capacity, and decreased vital capacity.
- Total lung capacity remains unchanged due to increase in residual volume (RV) offsetting decreased vital capacity (VC).
Conceptual Understanding:
- Loss of elastic recoil causes small airway collapse during expiration leading to an increase in RV and FRC.
Volume Changes in Elderly Patients:
- Closing capacity, functional residual capacity, and residual volume increase with age.
Vital Capacity Effects:
- Reduced due to loss of lung elastic recoil, increased chest wall stiffness, and weakened respiratory muscles.

Common Cardiovascular Issues:
- Cardiac disease prevalence: hypertension, coronary artery disease (CAD), congestive heart failure (CHF), myocardial ischemia.
Indicators of Cardiac Reserve:
- Exercise tolerance and ability to perform activities of daily living.
Key Cardiovascular Changes:
- Arterial compliance, venous compliance, myocardial compliance, conduction: all decrease.
- Myocardial mass increases with aging.

Specific Cardiovascular Changes Detailed:
- Blood pressure: Increased
- Pulse pressure: Increased
- Systolic function: No change
- Diastolic function: Decreased
- Stroke volume: Decreased
- Heart rate: Decreased
- Cardiac output: De