What are the recommended intubation drugs and dosages for a general adult patient with potential cardiovascular disease, impaired renal or hepatic function, requiring sedation, analgesia, and neuromuscular blockade for intubation?

Recommended Intubation Drugs for Adults with Cardiovascular Disease and Organ Dysfunction

For a general adult patient with potential cardiovascular disease and impaired renal or hepatic function requiring intubation, use etomidate 0.2-0.4 mg/kg as the induction agent with either succinylcholine 1.0-1.5 mg/kg or rocuronium 1.0-1.2 mg/kg as the neuromuscular blocking agent, with fentanyl 1-2 mcg/kg for analgesia. 1

Induction Agent Selection

Etomidate is the preferred induction agent for patients with cardiovascular disease due to superior hemodynamic stability. 1 The Society of Critical Care Medicine confirms etomidate (0.2-0.4 mg/kg IV) provides the most favorable hemodynamic profile with no mortality difference compared to other agents, making it first-line for critically ill adults 1. In hemodynamically unstable patients specifically, use etomidate 0.3 mg/kg IV 1.

Alternative: Ketamine

Ketamine (1-2 mg/kg IV) serves as an alternative when etomidate is contraindicated or unavailable 1. However, ketamine shows higher rates of peri-intubation hypotension compared to etomidate (18.3% vs 12.4%, OR 1.4) 1. Critical caveat: In patients with depleted catecholamine stores (sepsis, chronic heart failure), ketamine may cause paradoxical hypotension despite its sympathomimetic properties 1, 2.

Dosing for Cardiovascular Disease

For a 70 kg patient with cardiovascular disease:

• Etomidate: 14-28 mg IV (0.2-0.4 mg/kg) 1
• Alternative Ketamine: 70-140 mg IV (1-2 mg/kg), though the American Society of Anesthesiologists recommends the higher end of this range for adequate hemodynamic stability 2

The American Heart Association recommends titrating etomidate in 20 mg increments every 10 seconds until loss of consciousness, rather than rapid bolus, to minimize hemodynamic instability 1.

Neuromuscular Blocking Agent Selection

The use of a muscle relaxant is strongly recommended to facilitate tracheal intubation (GRADE 1+). 3 Without a muscle relaxant, 350 patients out of 1,422 presented poor intubating conditions in analyzed studies 3.

First-Line: Succinylcholine

Succinylcholine 1.0-1.5 mg/kg IV is the first-line neuromuscular blocking agent when no contraindications exist. 1, 4 The FDA label specifies the average dose is 0.6 mg/kg, with an optimum range of 0.3 to 1.1 mg/kg for adults 4. For rapid sequence intubation specifically, use the higher end of this range 1.

For a 70 kg patient: Succinylcholine 70-105 mg IV 1, 4

Succinylcholine provides neuromuscular blockade in approximately 1 minute, with maximum blockade persisting for about 2 minutes and recovery within 4-6 minutes 4. The effect lasts seven to eight minutes using laryngeal electromyography 3.

Alternative: Rocuronium

When succinylcholine is contraindicated, use rocuronium 1.0-1.2 mg/kg IV. 1, 5 The FDA label confirms that large bolus doses of 0.9 or 1.2 mg/kg can be administered under opioid/nitrous oxide/oxygen anesthesia without adverse cardiovascular effects 5. Higher doses (≥0.9 mg/kg) are required for optimal rapid sequence conditions comparable to succinylcholine 1.

For a 70 kg patient: Rocuronium 70-84 mg IV 1, 5

Rocuronium at 1.2 mg/kg provides onset in 55±14 seconds, similar to succinylcholine at 50±17 seconds 6. However, clinical duration is significantly longer with rocuronium 6.

Comparison of Agents

A noninferiority RCT of 1,248 patients found first-pass success rates of 74.6% with rocuronium (1.2 mg/kg) versus 79.4% with succinylcholine (1 mg/kg), with results inconclusive based on a 7% noninferiority margin 3. Injecting sugammadex after rocuronium gives better results than succinylcholine in terms of mean recovery time (4.7 min) and individual variability 3.

Analgesia

Administer fentanyl 1-2 mcg/kg prior to induction. 2 Short-acting opioids improve intubating conditions but carry higher risk of prolonging apnea 2. The American Society of Anesthesiologists recommends this dosing range specifically 2.

For a 70 kg patient: Fentanyl 70-140 mcg IV 2

Remifentanil 1.0 mcg/kg with continuous infusion of 0.1 mcg/kg/min suppresses cardiovascular reactions to endotracheal intubation more effectively than fentanyl during etomidate induction 7. However, fentanyl remains more practical in most emergency settings.

Critical Sequencing and Timing

The sedative-hypnotic agent (etomidate or ketamine) MUST be administered before the neuromuscular blocking agent to prevent awareness during paralysis. 1, 3 A prospective observational study identified an incidence of awareness of 2.6% (10/383) in patients intubated in the ED, with most patients who had awareness receiving a short-acting sedative and long-acting NMBA 3.

Recommended Sequence:

1. Fentanyl 1-2 mcg/kg IV (3 minutes before induction) 2
2. Etomidate 0.2-0.4 mg/kg IV (titrate to loss of consciousness) 1
3. Immediately after loss of consciousness: Succinylcholine 1.0-1.5 mg/kg OR Rocuronium 1.0-1.2 mg/kg 1
4. Intubate at 60 seconds after neuromuscular blocker 8

Contraindications to Succinylcholine

Do not use succinylcholine if the patient has: 8

• History of malignant hyperthermia
• Known myopathy or muscular dystrophy
• Immobilization >3 days
• Burns or crush injuries
• Spinal cord injuries
• Hyperkalemia risk

In these cases, use rocuronium 0.9-1.2 mg/kg with sugammadex immediately available for reversal 8.

Post-Intubation Sedation and Analgesia

Critical pitfall: Rocuronium's longer duration of action may delay provision of post-intubation analgosedation. 3 Most studies reported that post-intubation analgosedation was provided more rapidly when succinylcholine was administered 3. Patients receiving rocuronium are more likely to receive lower doses of sedative and analgesic infusions after intubation, placing them at risk of being awake under paralysis 9.

Ensure post-intubation sedation is initiated within 7 minutes (median time to first intervention). 10 After a pharmacy-led educational program, the median time to first analgosedative intervention was 7 minutes (IQR 3-13 minutes) with a median of 2 interventions occurring in the first 30 minutes post-RSI 10.

Special Considerations for Renal/Hepatic Dysfunction

For patients with impaired renal or hepatic function, etomidate remains the safest choice as it has minimal organ-dependent metabolism 1. Rocuronium is primarily eliminated hepatically, so consider dose reduction or use succinylcholine in severe hepatic impairment 5. Succinylcholine is metabolized by plasma cholinesterase and may have prolonged duration in severe hepatic disease 4.

Safety Measures

Ensure the following are immediately available: 8, 1

• Sugammadex (if using rocuronium) for reversal in "cannot intubate, cannot ventilate" scenarios 1
• Dantrolene (if using succinylcholine) for malignant hyperthermia 8
• Atropine for bradycardia, especially with repeat succinylcholine dosing 8
• Vasopressors for hemodynamic support 3

Use a peripheral nerve stimulator to monitor neuromuscular blockade and guide additional dosing. 5, 8