Anesthesia for Elderly Patient with Hip Fracture Case File

Anesthesia for Elderly Patient with Hip Fracture Case File

Lydia Conlay, MD, PhD, MBA, Julia Pollock, MD, Mary Ann Vann, MD, Sheela Pai, MD, Eugene C. Toy, MD

Case 12

An 88-year-old man slipped on the kitchen floor yesterday and fractured his right hip. He is scheduled for an open reduction and internal fixation (ORIF) of the fracture. His past medical history includes coronary artery disease with remote coronary stent placement, congestive heart failure, and hypertension. He is not aware of angina, and states that he sleeps on one pillow at night. However, on interview, he is noted to be mildly confused. He is oriented to time and place, but thinks the year is 1974. He has a sedentary lifestyle, and leaves his apartment only to go to his physician’s office, and the pharmacy. His housekeeper performs most of his daily chores, including grocery shopping. The patient’s medications include metoprolol, clopidogrel, aspirin, lisinopril, and simvastatin. He took NSAIDs as needed for arthritic pain prior to the fall. The patient has no known drug allergies.

The physical examination reveals an elderly, cachectic male 5 ft 8 in tall, weighing 145 lb. His vital signs include a blood pressure of 135/67 mm Hg, heart rate of 66, and respiratory rate of 16 with an oxygen saturation of 98% on room air. He has a mild limitation of mouth opening, and on airway examination, his airway is a Mallampati class 1. His heart is regular and slow, and his lungs are clear. Laboratory values include a hemoglobin of 9.8 g/dL, a platelet count of 221,000, an international normalized ratio (INR) of 1.1, potassium of 4.1 mEq/L, and blood urea nitrogen (BUN) of 35, and a creatinine of 1.2 mg/dL. His ECG is notable for left ventricular hypertrophy, and his chest x-ray is normal.

➤ What are the preoperative concerns for this patient?

➤ What are the anesthetic options?

ANSWERS TO CASE 12:

Anesthesia for Elderly Patient with Hip Fracture

Summary: This is an elderly patient with revascularized coronary artery disease who presents for ORIF of a right hip fracture.

➤ Preoperative considerations for this patient include understanding why he fell (did he trip, have a stroke, an arrhythmia, etc.), the status of his mental function and ischemic heart disease including the possibility of stent thrombosis, his NPO status prior to coming to the operating room, the intraoperative possibility of massive blood loss, volume depletion, and coagulopathy.

➤ Anesthetic options: This patient can have this procedure done under general or regional anesthesia in the form of epidural, spinal, or combined spinal epidural block. Given the dual platelet therapy, general anesthesia is probably a safer option. There is increased risk of epidural hematoma with neuraxial anesthesia.

ANALYSIS

Objectives

1. Discuss the preoperative evaluation of an elderly patient.

2. Identify some of the choices of anesthetic technique for hip surgery.

3. List the benefits and risks of regional anesthesia and general anesthesia in the geriatric population.

Considerations

The primary issues for this patient are his confusion, his anemia, and the history of coronary artery disease and stent placement. It is not uncommon for elderly patients to become confused, particularly as their environment changes and they experience pain. However, since the fracture occurred as the result of a fall, it is always important to keep in mind that the “fall” may in fact have represented another type of event. Similarly, a fall also carries the potential for other occult injuries, including a subdural hematoma. Since a hip fracture is not an urgent emergency, these possibilities will usually have been carefully considered prior to a patient’s coming to the operating room. Nevertheless, they are important possibilities to keep in mind while caring for these fragile patients.

It is also not uncommon for patients to loose a unit of blood silently into a hip fracture before coming to the operating room. Thus, it is important to ascertain the patient’s volume status prior to induction of general anesthesia or placement of a regional anesthetic. Blood should be available prior to surgery, and a large bore intravenous line placed and connected to a fluid warmer. Arterial pressure monitoring in this patient allows for beat-to-beat BP monitoring as well as enable frequent hemoglobin and blood gas assessment.

In the presence of coronary artery disease, the risk of intraoperative and postoperative myocardial ischemia increase during periods of intense stimulation such as during induction, intubation, awakening, and in the presence of postoperative pain. Both general and regional anesthesia can be safely achieved. However, given the presence of both clopidogrel and quite possibly an NSAID, regional anesthesia loses favor as the risk of bleeding outweighs the benefits of a regional technique.

APPROACH TO

Anesthesia for Elderly Patient with Hip Fracture

Older individuals often present a multitude of issues which influence the choice of anesthetic to be provided. The aging process affects many of the body’s vital functions, many, relevant to the administration of an anesthetic. However, there is significant variability in the relationship between chronological age and physiological age. 

Aging reduces the requirement for and clearance of a variety of drugs. This is particularly an issue with respect to the sedative hypnotics, probably resulting from a combination of mechanisms such as a lower volume of distribution, fewer neurons, and an enhanced drug susceptibility. Sedative hypnotic drugs in the context of an anesthetic include anxiolytics, and the induction agents for general anesthesia. These drugs should be administered judiciously and in small doses, if at all.

Aging affects the cardiovascular system by decreasing the responsiveness of beta receptors. Hence, the maximum heart generated by the heart’s compensatory mechanisms is reduced with age. An elderly patient may or may not become tachycardic in the presence of fever. Similarly, tachycardia may or may not occur in the presence of hypovolemia. This has two potential consequences: first, acute hypovolemia may be missed; and second, arterial pressure may be more labile since it is one of the few remaining compensatory mechanisms. In addition, arteriosclerosis and coronary artery disease may necessitate that mean arterial pressure be maintained to preserve coronary perfusion.

Pulmonary reserve also declines with age. In particular, aging is associated with decreased vital capacity (VC) and increased residual volume (RV), an increased air trapping and V/Q mismatch (especially when supine), a reduction in the resting arterial O2 tension (PaO2), a decreased ventilatory response to hypoxia or hypercarbia, and a reduced ability to cough or clear secretions. These alterations in respiratory physiology can directly affect the ability to ventilate and oxygenate a patient during surgery, and may necessitate a delay in extubation.

Hepatic and renal function also declines with age, often leading to a reduced elimination of drugs. A patient’s ability to handle a glucose load also significantly declines with age.

The Preoperative Evaluation: Special Items in Elderly Patients

The goal of the anesthetic is to assess and optimize the patient’s condition as much as possible prior to the procedure. If possible, it is desirable to note the patient’s functional status prior to the illness—both physically and mentally. Any evidence of central nervous system dysfunction and/or residual from previous illnesses such as stroke should be carefully documented, since these conditions could evolve during the course of the current hospitalization.

If a patient has coronary artery disease, it is especially important to take a clear history as to whether or not chest pain is occurring, whether it is stable and has been assessed, or whether the pain represents a new and thus acute event. The functional capacity, such as ability to walk two flights of stairs (equivalent to 4 METS) or more vigorous activity (ie, any type of sports) will generally indicates an adequate cardiac reserve for a surgical procedure of low or intermediate cardiac risk. But if the chest pain has been present and escalating in requirements for sublingual nitroglycerin, then there may be active ischemia and further assessment of myocardial function should be performed. Other symptoms such as bilateral swelling of the ankles, palpitations, and gastric distress may also suggest myocardial dysfunction.

Patients should also be asked about bruising (increased or more noticeable or lack of recovery from), epistaxis, or bleeding from the gums while brushing teeth as history directed questions which point to bleeding abnormalities. Family or medical history questions which indicate bleeding or clotting disorders such as sickle cell disease, factor deficiencies (ie, factor 5, factor 7, factor 9...), von Willebrand disease, and platelet abnormalities, should guide one away from regional anesthesia techniques.

Medications must also be carefully reconciled with the patient or his or her caregiver. This includes not only what medications have been prescribed, but whether they have actually been taken (perhaps in excess, or perhaps not at all).

The Anesthetic Plan

The patient’s physical condition and the surgical procedure dictate the anesthetic plan. General anesthesia typically involves an intravenous induction, paralysis, subsequent intubation, and maintenance with opiates and volatile agents. In some individuals, securing the airway is advantageous to prevent aspiration and allow for the administration of 100% oxygen. General anesthesia may also be more desirable if the anticipated surgical time is beyond the duration of the regional block, or if the procedure is sufficiently long that the patient cannot lie still even with sedation in a prolonged supine position.

Regional techniques are advantageous because of the reduced need for systemic medications which may alter the patient’s sensorium or cause hypotension and myocardial depression. Indeed, regional anesthetics such as spinal are the anesthetics of choice for reduction of a hip fracture. An epidural has the added advantage of offering surgical anesthesia and postoperative pain relief. Any hemodynamic changes from a regional-induced sympathectomy can be easily controlled with vasopressors. The disadvantages of regional anesthetics in the elderly include difficulty in placing the block, particularly in situations such as a fractured hip, where it can be most painful to turn a patient on his or her side or ask them to sit for block placement. Additional risks are rare, but serious, and include epidural hematoma, seizure, and neural injury, and rarely, cardiac arrest. The incidence of spinal headache decreases with age, and rarely presents in the geriatric population.

In an anticoagulated patient, regional anesthesia is relatively contraindicated. The American Society of Regional Anesthesia (ASRA) consensus statements for oral anticoagulants states that medications must be discontinued for a minimum of 7 days prior to neuraxial anesthesia in most cases. On history and physical examination, questions as to medications which are being actively used for anticoagulation should be elicited, that is, warfarin, low-molecular-weight heparins, recent administration of thrombin inhibitors, platelet inhibiting agents, or fibrinolytics. Unfractionated heparin, administered subcutaneously more than 1 hour from needle placement, has not been associated with any significant comorbidity or mortality. Concomitant use of aspirin and/or use of herbal medications such as ginkgo, ginseng, and garlic have also been noted to have increased risk for bleeding abnormalities.

Age is the number one factor to be considered in the incidence of postoperative delirium. Sedative hypnotics such as the benzodiazepines, barbiturates and inhaled agents, or perhaps general anesthesia itself likely contribute to this syndrome. In addition, the combination of pain, and new surroundings may well contribute to postoperative delirium as well. Postoperative cognitive dysfunction, sometimes lasting for weeks, sometimes months, and sometimes forever is a recently recognized phenomenon which occurs most frequently in elderly patients. The etiologies of this syndrome are as of yet unknown. However, one hypothesis relates postoperative cognitive dysfunction to “deep” general anesthesia, and some general anesthetics have been shown to cause neuronal cell death in vitro.

The social situation of elderly patients who have recently undergone surgery deserves special mention. The geriatric patient is susceptible to loss of “routine” items of daily living, such as missing dentures and glasses. These items may be exceedingly difficult to replace in the patient recovering from surgery, and their loss may perpetuate postoperative delirium. The home environment, and whether a patient can care for himself is also a consideration prior to discharge from the hospital, particularly for ambulatory procedures where patients are discharged on the same day as the operation.

Comprehension Questions

12.1. Which of the following is the most concerning symptom/sign suggestive of impaired cardiac function?

    A. Ability to perform daily activities such as normal hygienic maintenance, but unable to ambulate up/down two flights of stairs

    B. Inactivity

    C. New onset of shortness of breath with lying flat

    D. Chest pain which improves on treatment with omeprazole

12.2. Regional anesthesia for a total knee replacement is advantageous because of which of the following?

    A. It decreases postoperative nausea and emesis by reducing opioid required for pain relief.

    B. It increases total surgical blood loss.

    C. It increases the risk of deep vein thrombosis (DVT).

    D. It is very useful in patients with atrial fibrillation who are anticoagulated.

12.3. Which of the following is increased in elderly patients compared with their younger counterparts?

    A. Vital capacity

    B. Air trapping

    C. Resting arterial oxygen tension (PaO2)

    D. Ventilatory response to hypoxia or hypercarbia

ANSWERS

12.1. C. New onset of shortness of breath raises suspicion of an acute change in the patient’s cardiovascular status. Assessment of cardiac function in the preoperative patient with cardiac disease includes assessment of exercise tolerance. The ability to climb two flights of stairs demonstrates a metabolic equivalent (MET) of 4. Studies have demonstrated that a MET = 4 is reasonable for intermediate risk surgical procedure. While functional status is a good indicator of cardiac function, geriatric patients may be inactive for other reasons as well. That’s why a careful history and physical examination are important. Chest pain which responds to omeprazole (D) is most likely to represent gastric reflux.

12.2. A. Regional anesthesia provides preemptive and superior analgesia when compared to parenteral therapy. Parenteral narcotics also have side effects such as somnolence and a decreased arousability. Neuraxial blockade actually reduces surgical blood loss. Neuraxial blockade also causes sympathectomy, which reduces the incidence of DVT by decreasing the thrombogenicity. Regional anesthesia is contraindicated in patients who are anticoagulated.

12.3. B. The propensity for air trapping is increased with age. In contrast, the vital capacity (A), arterial oxygen tension (C), and ventilatory response to hypoxia or hypocarbia are decreased with age.

Clinical Pearls

➤ Regional anesthesiology should be considered for as the primary anesthetic for repair of a hip fracture.

➤ Regional anesthesia is relatively contraindicated in patients who are anticoagulated and/or receiving antiplatelet therapy.

➤ Administering anesthesia in the geriatric population must be guided by the physiologic changes that accompany the aging process, and which affect almost every major organ system.

➤ Postoperative cognitive dysfunction is a major consideration in choosing an anesthetic technique for the elderly.

References

Belmar CJ, Barth P, Lonner JH, Lotke PA. Total knee arthroplasty in patients 90 years of age and older. [Journal Article. Research Support, Non-U.S. Gov’t] Journal of Arthroplasty. Dec. 1999;14(8):911-914. 

Eagle, Kim A MD et al. ACC/AHA Guideline update for perioperative cardiovascular evaluation for noncardiac surgery. Anesthesia & Analgesia. 2002;94: 1052-1064: Updated in 2007. 

Modig J, Borg T, Karlstrom G, et al. Thromboembolism after total hip replacement: Role of epidural and general anesthesia. Anesthesia and Analgesia. 1983;62:174-180. 

Rowlingson, John C, Hanson, Peter B. Neuraxial anesthesia and low-molecularweight heparin prophylaxis in major orthopedic surgery in the wake of the latest American Society of Regional Anesthesia Guidelines. [Miscellaneous] Anesthesia and Analgesia. May 2005;100(5):1482-1488. 

Yeager M, Glass D, Neff R, et al. Epidural anesthesia and analgesia in high risk surgical patients. Anesthesiology. 1987;66:723-724.

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