Spinal Anesthesia in Elderly

Introduction

Spinal anesthesia is a better option than general anesthesia in elderly patients. Regional anesthesia remains the patient awake, while general anesthesia makes the patient unconscious during surgery. With unconsciousness, other parameters, like the airway, must be managed. Good results have been noted in the low doses of spinal anesthesia. The surgery of the elderly requires preoperative evaluation, better monitoring during surgery, and postoperative care with a lengthy hospital stay. This topic explains spinal anesthesia usage in the elderly.

What Is Spinal Anesthesia?

Spinal anesthesia is given to numb the areas of the lower back, legs, and buttocks. Although spinal anesthesia can numb the areas of the neck and arms, the doctor knowingly delivers the injection to the backbone of the lower back (lumbar) area. The injection on the lower back prevents any harm to the neck (cervical) and chest region. Spinal anesthesia is injected into the spinal sacs in the subarachnoid space. It is a form of regional anesthesia.

What Are the Physiological Changes Associated With the Elderly That Affects Anesthesia?

The elderly are people more than 65 years of age. The aging has made their organ system reserves low. As a result, the body's organ system has reduced its work. This reduction causes physiological changes to occur in the elderly body. Some changes are:

• Nervous System - There is a decrease in neuron cells of the nervous system, causing less neuron to neuron contacts. Brain volume is decreased. The reflexes of the body also decrease. To overcome more complications, a doctor has to go for a low dose of anesthesia.

• Cardiovascular System - The change in the size of the heart's left chamber is seen, which has increased, and decreased the cardiac output. Body heart reflexes (baroreceptors) that control high blood pressure start depleting along with the rigidity of the cardiac arteries. The induction of the anesthetic agents can affect blood pressure.

• Respiratory System - Along with other changes in the lungs, the chest wall has decreased, and the strength of the respiratory muscle has reduced. The surface for the exchange of gases (oxygen and carbon dioxide) decreases smaller airways and thus requires more input for breathing. The respiratory changes could easily lead to a low oxygen level in surgery, and after surgery, regular respiratory rate monitoring is essential. Respiratory complications are easy to develop in the elderly.

• Kidneys - The kidney working for urine and other mineral outputs starts decreasing its work. The kidney reflexes for maintaining the mineral levels in the body are also depleted. Monitoring urine output during and after the surgery is essential.

• Liver - The drug's metabolism is by the liver; with aging, it might get upset, and sensitivity to the drugs can be brought. These changes can increase their chances of anesthetic drug sensitivity.

• Nutrition - The elder patients suffer from poor nutrition. These patients should not have prolonged fasting during preoperative times.

These changes indicate that the elderly population can have heart disease, hypertension (high blood pressure), diabetes (abnormal blood glucose level), and lower blood flow to the kidney and brain.

What Are the Indications for Spinal Anesthesia in the Elderly?

Indications for spinal anesthesia are:

• Lower abdomen surgery.

• Orthopedic surgery includes the pelvis, hip, femur, and knee.

• Joint replacement surgery.

• Fracture treatments related to hip, pelvic, and femur bone.

How Has Spinal Anesthesia Been Used in Elderly Patients?

Spinal anesthesia is widely used in the elderly. The orthopedic surgery of elderly patients uses spinal anesthesia more often than general or even epidural anesthesia. Spinal anesthesia has many advantages. Although the elderly are dealing with a set of medical problems and increased recovery time, spinal anesthesia has improved their postoperative state by decreasing the complication occurring.

What Are the Advantages of Spinal Anesthesia in the Elderly Over General Anesthesia?

Advantages of spinal anesthesia include:

• Spinal anesthesia has better efficacy than general anesthesia.

• It is a more rapid action than general anesthesia.

• It causes fewer effects on the mental status of the patient.

• It causes less blood loss in surgery.

• It is protective against clot formation.

• It shows fewer postoperative complications, like postoperative pain issues are minimum.

• Less use of opioids.

• Decreased skin irritation.

What Are the Disadvantages of Spinal Anesthesia in the Elderly?

Disadvantages of spinal anesthesia are:

• Severe hypotension.

• Hypothermia (low body temperature).

• Shivering.

• Infection.

• Headache.

• Backache.

What Is the Anesthetic Drug Used in Spinal Anesthesia for the Elderly?

The elder patient provides a low dose of local anesthesia and opioids for both anesthetic and analgesic effects. A low dose will overcome many unwanted changes the elderly body will have, thus presenting fewer side effects. The drugs used in spinal anesthesia are:

• Fentanyl - Fentanyl is an opioid with a rapid onset and short duration of action. It is advantageous in ambulatory surgery (surgery outside the operation theater). It affects the respiratory system less and prevents the patient from extended hospital stays.

• Morphine - Morphine is a slow-acting drug. It is not suitable for ambulatory services. It also has fewer respiratory risk factors with low use. It provides analgesic effects.

• Bupivacaine - It is an anesthetic drug. A low dose of Bupivacaine with a minimum dose of opioid-like Fentanyl or Morphine has given better results for spinal anesthesia.

• Ropivacaine - It is an anesthetic drug.

• Sufentanil - It is a derivative of Fentanyl opioid.

• Dexmedetomidine - It is a new drug added to spinal anesthesia as a local anesthesia adjuvant.

Is Spinal Anesthesia Usage Safe for the Elderly?

Spinal anesthesia is used daily in the elderly as it has benefits compared with general anesthesia. But a few disadvantages need to be managed by a doctor. First, elderly patients are at risk of developing hypothermia and shivering. These can lead to more oxygen consumption with increased respiratory rate and cardiac output. To overcome this, doctors use a low dose of Bupivacaine which lowers the symptoms of shivering during spinal anesthesia in the elderly. Continually using spinal anesthesia can lead to complications like infection and headache. So, appropriate use with an exact dose of spinal anesthesia is important for the patient's safety.

Conclusion

Spinal anesthesia in elderly patients primarily uses orthopedic surgery like hip fractures or knee replacements. They have many advantages over general anesthesia use in elderly patients. They have provided better postoperative outcomes than general. They have few complications postoperatively, like hypothermia or hypotension. With continuous use of spinal anesthesia, they can have infections too.