What is the most appropriate IV anesthetic for induction in a patient with coronary artery disease and congestive heart failure undergoing hip fracture repair?

Etomidate is the Most Appropriate Intravenous Anesthetic for Induction

For this 74-year-old patient with coronary artery disease and congestive heart failure undergoing hip fracture repair, etomidate is the most appropriate IV anesthetic for induction if general anesthesia is required, though spinal anesthesia should be strongly considered as the preferred technique.

Primary Consideration: Anesthetic Technique Selection

The Association of Anaesthetists guidelines recommend that spinal/epidural anesthesia should be considered for all patients undergoing hip fracture repair, unless contraindicated 1. This is particularly important for elderly patients with significant cardiac comorbidities, as regional anesthesia may reduce postoperative confusion and avoids the cardiovascular depression associated with general anesthesia 1, 2.

However, if general anesthesia is necessary (due to contraindications to neuraxial blockade, patient refusal, or clinical circumstances), the choice of induction agent becomes critical.

Etomidate: The Optimal Choice for Cardiac Patients

Etomidate provides the most hemodynamically stable induction profile in patients with coronary artery disease and heart failure 3, 4, 5. The evidence supporting this is compelling:

Hemodynamic Stability

• Etomidate causes minimal cardiovascular depression, with only an 8.5% decrease in mean arterial pressure and a negligible 2.8% increase in heart rate 6
• Cardiac output decreases by only 7.6% with etomidate, significantly less than other agents 6
• In patients with CHD undergoing major surgery, etomidate is associated with fewer cardiovascular events (bradycardia, hypotension, ST-T segment changes) compared to propofol 5

Comparative Evidence

• A 2010 randomized trial in patients with coronary artery disease and left ventricular dysfunction (ejection fraction <45%) found that while all four agents (etomidate, propofol, midazolam, thiopentone) caused a 30-40% decrease in cardiac index, etomidate was acceptable for induction 3
• A 2021 study demonstrated that etomidate-based anesthesia resulted in significantly fewer cardiovascular events and smaller hemodynamic changes than propofol-based anesthesia in CHD patients 5
• Even when compared to ketamine-propofol combination ("ketofol"), etomidate provides superior hemodynamic stability with higher nadir MAP and SVR 7

Why Not the Other Options?

Propofol

• Causes significant vasodilation and myocardial depression 8, 4
• The FDA label specifically warns that elderly, debilitated, or ASA-PS III/IV patients require reduced doses (1-1.5 mg/kg vs 2-2.5 mg/kg) and that "a rapid bolus should not be used, as this will increase the likelihood of undesirable cardiorespiratory depression including hypotension" 8
• In cardiac patients, propofol causes decreases in preload and afterload proportional to blood concentrations, with higher rates of hypotension requiring vasopressor support 8, 5
• Propofol-based anesthesia resulted in significantly higher incidences of bradycardia, hypotension, and ST-T segment changes compared to etomidate 5

Ketamine

• While ketamine has sympathomimetic properties that can support blood pressure, it is not listed as a standalone option and is typically used in combination with propofol 7
• Even the ketamine-propofol combination shows inferior hemodynamic stability compared to etomidate 7

Midazolam

• Midazolam was most effective at preventing intubation stress response but still caused significant decreases in cardiac index (36-38%) during induction 3
• It is generally not preferred as a sole induction agent in high-risk cardiac patients

Critical Dosing and Administration

If etomidate is used for induction in this patient:

• Dose: 0.2 mg/kg administered slowly over 60-90 seconds 3, 6
• Avoid rapid bolus administration to minimize hemodynamic perturbations
• Prepare for potential myoclonic movements, which are a known side effect but not clinically significant 6

Important Caveats

Adrenal Suppression Concern

• Etomidate causes transient adrenal suppression and reduced cortisol levels 4
• However, a 2015 study demonstrated that etomidate can be safely used without serious cortisol suppression lasting more than 24 hours 4
• This concern should not preclude its use in this acute setting where hemodynamic stability is paramount for mortality and morbidity outcomes

Monitoring Requirements

• The Association of Anaesthetists recommends carefully administered, invasively monitored general anesthesia in patients with significant cardiac disease 1
• Continuous monitoring including pulse oximetry, ECG, and invasive blood pressure monitoring should be employed 2
• Consider short-term admission to higher-level care postoperatively 1

Multimodal Approach

• Regardless of induction agent, peripheral nerve blockade (femoral nerve or fascia iliaca block) should be considered as an adjunct to extend postoperative non-opioid analgesia 2
• Avoid opioids as the sole adjunct due to risk of respiratory depression and postoperative confusion in elderly patients 1, 2

Clinical Algorithm

1. First choice: Proceed with spinal anesthesia if no contraindications exist 1, 2
2. If general anesthesia required: Use etomidate 0.2 mg/kg over 60-90 seconds for induction 3, 6
3. Ensure: Invasive blood pressure monitoring is established 1
4. Add: Peripheral nerve blockade for postoperative analgesia 2
5. Avoid: Rapid bolus administration and high-dose opioid techniques 1, 8

The priority is maintaining coronary and cerebral perfusion pressures while minimizing myocardial oxygen demand—etomidate best achieves this balance in patients with coronary artery disease and heart failure 5, 6.