CHPPC Module 6, Section 2: Rapid Sequence Intubation (RSI)
MODULE 6, PART 1: ED PHARMACY WORKFLOWS

Section 2: Rapid Sequence Intubation (RSI)

A deep dive into one of the highest-stakes procedures in emergency medicine and the pharmacist’s indispensable role in ensuring patient safety and procedural success.

PART 2.1

The “Why”: Indications for Emergency Intubation

Understanding the Critical Triggers for Airway Management

Rapid Sequence Intubation is not an elective procedure; it is the definitive, and often life-saving, management of a patient’s failing airway. The decision to intubate is a complex clinical judgment, but it generally boils down to three fundamental failures. As a pharmacist at the bedside, understanding these “whys” is crucial. It provides the immediate clinical context for the medications you are preparing and allows you to anticipate the needs of the team. When you hear the indication for intubation, your mind should immediately begin processing the potential hemodynamic consequences, the patient’s specific comorbidities, and which RSI agents are most appropriate. This is not just about grabbing vials; it’s about active cognitive participation in a critical event.

The Retail Pharmacist Analogy: The Pre-Flight Checklist

In retail, your verification process is a meticulous safety check before a medication is dispensed. Think of the decision to intubate as a pilot’s decision to take off. There’s a pre-flight checklist, and any “no-go” items ground the plane. The three main indications for intubation are like the three critical systems a pilot checks: mechanical, electrical, and environmental. A failure in any one system means the plane is not safe to fly. You, as the pharmacist, are like the ground crew chief. You don’t make the decision to fly, but when the pilot says “go,” you are the one who ensures the plane is perfectly fueled (the right drugs) and all systems are primed for a successful launch (the right doses, the right timing). Knowing *why* the plane needs to take off helps you prepare for the specific challenges of that flight.

Masterclass Table: The Three Pillars of Intubation

Indication Core Problem Classic Clinical Scenarios Pharmacist’s Anticipatory Thought Process
1. Failure to Maintain or Protect the Airway Anatomical / Mechanical
  • GCS < 8 ("Less than 8, intubate"): Severe traumatic brain injury, large stroke, overdose. The patient cannot cough or gag to prevent aspiration.
  • Physical Obstruction: Angioedema, anaphylaxis, epiglottitis, severe facial/neck trauma with hematoma.
 “This is a physical problem. The airway is closing. We may only get one shot at this. I need to have my drugs perfectly calculated and ready.”
2. Failure of Ventilation or Oxygenation Physiological / Gas Exchange
  • Hypoxemic Failure: Severe ARDS, massive pulmonary embolism. The lungs are failing to get oxygen into the blood despite maximal non-invasive support.
  • Hypercapnic Failure: Status asthmaticus, severe COPD exacerbation. The patient is tiring out and can no longer blow off CO₂, leading to severe acidosis.
 “This is a lung problem. The patient is already physiologically brittle. Which induction agent will be safest for their hemodynamics and lung mechanics? Ketamine might be ideal for the asthmatic.”
3. Anticipated Clinical Course Proactive / Strategic
  • Profound Shock: A patient in deep septic shock is using immense energy just to breathe. Intubating them reduces the work of breathing, conserving oxygen for vital organs.
  • Procedural Sedation: An unstable patient who needs to go for an urgent CT scan or to the interventional radiology suite.
 “The team is being proactive. This patient is circling the drain. Let’s intubate now in a controlled setting rather than waiting for them to code. Their blood pressure is already low, so etomidate is my top choice.”
PART 2.2

The Pharmacist’s Role: The Seven Ps of RSI

Mastering the Medications for a Flawless Procedure

Here is where your expertise becomes front and center. The “Seven Ps” is a mnemonic that outlines the entire RSI procedure. While the physician is leading the procedure and the respiratory therapist is managing the ventilator, you are the master of the medications for several of these steps. Your role is not passive. You are an active participant, responsible for ensuring the right drugs, at the right doses, are available at the right time. You are the final safety check in a high-stakes, irreversible process.

The Seven Ps of RSI & Your Role
  1. Preparation: Your ‘mise en place’. You’re verifying the “recipe” (patient’s weight, allergies, hemodynamic status), calculating doses, drawing up medications, and labeling them clearly.
  2. Preoxygenation: The patient is given 100% oxygen for 3-5 minutes to create an oxygen reservoir in the lungs, preventing desaturation during the apneic period of intubation. Your role here is to ensure your medications are ready before this step is complete.
  3. Pretreatment: Administration of ancillary drugs to blunt the physiological response to intubation. (Use of these agents is debated and protocol-dependent).
  4. Paralysis with Induction: This is the core medication step. The sedative and paralytic are given in rapid succession. You state the drug name and dose out loud for final verification before handing it off.
  5. Positioning: The patient’s head and neck are positioned for optimal visualization of the vocal cords.
  6. Placement of the Tube: The physician inserts the endotracheal tube and confirms its placement.
  7. Post-intubation Management: Your final, critical quality check. You ensure the follow-up infusions for sedation and analgesia are started immediately, preventing any gap in therapy and the inhumane state of being “awake and paralyzed.”

Masterclass: The RSI Medication Arsenal

2.2.1 The Induction Agent (The Sedative)

The first step is to induce a state of deep unconsciousness. The choice of agent is a critical decision based almost entirely on the patient’s hemodynamic status—specifically, their blood pressure. A poor choice here can be fatal.

The Perils of Post-Intubation Hypotension

Intubation itself is a high-risk procedure that can cause a drop in blood pressure. Many induction agents are also potent vasodilators and negative inotropes. In a patient who is already hemodynamically fragile (e.g., in septic shock), the combination of the procedure and the wrong drug can lead to profound hypotension and cardiac arrest. This is why your drug selection matters so much.

Etomidate (Amidate®): The Hemodynamically Stable Choice
  • Mechanism: A carboxylated imidazole derivative that enhances the effect of GABA at the GABA-A receptor, causing profound sedation.
  • The Big Advantage: It is renowned for being “hemodynamically neutral,” causing minimal to no drop in blood pressure or change in heart rate.
  • Dosing: The standard induction dose is $$0.3 \text{ mg/kg}$$ of actual body weight, rounded to a reasonable volume. For an 82 kg patient: $$0.3 \frac{\text{mg}}{\text{kg}} \times 82 \text{ kg} = 24.6 \text{ mg}$$. You would draw up 25 mg and state the calculated dose clearly: “Calculated dose is 24.6 mg. I have 25 mg drawn up.”
  • Pharmacist’s Role: Because of its supreme hemodynamic safety profile, this is the go-to agent for patients in shock, trauma, or with underlying cardiac dysfunction. Your role is to advocate for its use in these hemodynamically tenuous patients.
  • The Controversy: Causes transient adrenal suppression by inhibiting the enzyme 11-beta-hydroxylase, which can decrease cortisol production for up to 24 hours. While the clinical significance of a single dose is heavily debated, this is why some clinicians prefer ketamine in patients with septic shock who may already have relative adrenal insufficiency.
Ketamine (Ketalar®): The Sympathomimetic Dissociative
  • Mechanism: A unique agent that causes “dissociative anesthesia” by acting as an NMDA receptor antagonist.
  • Key Effects: Causes a central sympathomimetic surge (release of catecholamines), which typically increases heart rate and blood pressure. It also provides potent bronodilation and maintains the patient’s respiratory drive, which can be beneficial. It is also a potent analgesic.
  • Dosing: The standard RSI dose is $$1 \text{ to } 2 \text{ mg/kg}$$ IV. For a 90 kg patient, a dose of 1.5 mg/kg would be 135 mg.
  • Pharmacist’s Role: This is the drug of choice for patients being intubated for status asthmaticus or severe COPD. Its bronchodilatory properties can help relieve the underlying bronchospasm. It is also an excellent choice for hypotensive patients, provided they are not catecholamine-depleted (e.g., in late-stage shock), in which case its direct myocardial depressant effects could be unmasked.

2.2.2 The Paralytic Agent (The Neuromuscular Blocker)

After inducing unconsciousness, a paralytic agent is given to relax the muscles of the jaw and vocal cords, facilitating easy passage of the endotracheal tube and preventing vomiting. This is an irreversible step. Once the paralytic is given, the team is absolutely committed to securing the airway.

Succinylcholine (Anectine®): The Depolarizer
  • Mechanism: The only depolarizing NMBA. It is essentially two acetylcholine molecules linked together. It binds to the nicotinic acetylcholine receptor and causes persistent depolarization, leading to initial muscle fasciculations followed by flaccid paralysis.
  • Key Features: Ultra-rapid onset (45-60 seconds) and a very short duration of action (6-10 minutes). This short duration was historically seen as a safety feature in a “Can’t Intubate, Can’t Oxygenate” scenario, as spontaneous respirations might return quickly.
  • Dosing: The standard RSI dose is $$1.5 \text{ mg/kg}$$ IV of actual body weight. It is crucial not to underdose, as this can lead to incomplete paralysis and a failed intubation attempt.
Critical Safety Role: Succinylcholine Contraindications

Succinylcholine can cause sudden, fatal hyperkalemia in certain patients by causing a massive efflux of potassium from muscle cells. Your job as the pharmacist is to rapidly screen for these absolute contraindications before the drug is given. Voicing a concern—”Wait, this patient has a crush injury, we cannot use succinylcholine”—is a life-saving intervention.

  • Pre-existing Hyperkalemia (e.g., ESRD with a missed dialysis session).
  • Conditions with upregulation of acetylcholine receptors: Crush injuries, severe burns, or spinal cord injuries (typically > 48 hours out).
  • Prolonged immobility or denervating neuromuscular diseases (e.g., Guillain-Barré, muscular dystrophy).
  • Personal or family history of Malignant Hyperthermia.
Rocuronium (Zemuron®): The Non-Depolarizer
  • Mechanism: A non-depolarizing NMBA that acts as a competitive antagonist at the acetylcholine receptor.
  • Key Features: Does not cause potassium release, making it a safer choice in many patients. When given at a high dose, its onset is nearly as fast as succinylcholine.
  • Dosing: The RSI dose is $$1.2 \text{ mg/kg}$$ IV of ideal or adjusted body weight. This high dose provides a rapid onset (~60-90 seconds) but comes with a much longer duration of action (45-60 minutes).
The Sugammadex Safety Net

The long duration of rocuronium was once a significant concern in a “Can’t Intubate, Can’t Oxygenate” (CICO) emergency. However, the advent of the reversal agent Sugammadex (Bridion®) has changed this paradigm. Sugammadex is a modified cyclodextrin that directly encapsulates and inactivates rocuronium molecules in the plasma, providing rapid and complete reversal of paralysis within minutes. The availability of Sugammadex as a “rescue” drug has made high-dose rocuronium the default paralytic in many, if not most, emergency departments.