About This RSI Drug Dose Calculator
This RSI Drug Dose Calculator is a clinical tool designed for emergency medicine physicians, intensivists, anesthesiologists, and other critical care professionals. Rapid Sequence Intubation is a high-risk, essential procedure for securing a definitive airway in critically ill patients. The core of a safe RSI is the swift, accurate administration of weight-based medications. This calculator provides instant dose calculations for the most commonly used induction and paralytic agents, minimizing cognitive load and reducing the risk of error during a stressful emergency. This tool, the RSI Drug Dose Calculator, should be used in conjunction with a comprehensive understanding of the RSI procedure.
All doses on this page are calculated using total body weight (TBW), which is the standard basis for emergency RSI dosing. In obesity, some clinicians dose the lipophilic induction agents (propofol, etomidate) on lean or adjusted body weight to avoid hemodynamic overshoot, whereas the neuromuscular blocking agents succinylcholine and rocuronium are dosed on total body weight to ensure rapid, reliable paralysis.
The ‘7 Ps’ of RSI Explained
The “7 Ps” is a mnemonic that provides a structured, sequential framework for performing a safe and effective Rapid Sequence Intubation. Following these steps ensures that critical actions are not missed.
- Preparation: This is arguably the most important step. It involves a “pre-flight” check to ensure all necessary equipment, drugs, and personnel are ready. This includes checking the laryngoscope light, cuff on the endotracheal tube, suction, and having backup airways (e.g., LMA, cricothyrotomy kit) immediately available. All drugs should be drawn up and clearly labeled.
- Preoxygenation: The goal is to maximize the patient’s oxygen reserve, allowing for a longer period of safe apnea during the intubation attempt. This is achieved by administering 100% oxygen via a non-rebreather mask or BVM (without positive pressure) for 3-5 minutes.
- Pretreatment: This step involves administering medications prior to induction to mitigate the adverse physiological responses to laryngoscopy and intubation (which can cause a massive catecholamine surge). The most common agent is fentanyl, used to blunt the sympathetic response. Lidocaine may be considered in patients with elevated intracranial pressure.
- Paralysis with Induction: This is the cornerstone of RSI. A potent induction (sedative) agent is given as a rapid IV push, followed immediately by a neuromuscular blocking agent (paralytic). The combination renders the patient unconscious and flaccid within a minute, creating optimal conditions for intubation while minimizing aspiration risk. In hemodynamically unstable or shocked patients, the induction-agent dose should be reduced (for example, ketamine ~0.5-1 mg/kg or etomidate ~0.15-0.2 mg/kg) to avoid precipitating peri-intubation hypotension and cardiovascular collapse; the paralytic dose is not reduced.
- Protection and Positioning: The patient should be positioned to align the oral, pharyngeal, and laryngeal axes. This is often called the “sniffing position.” Protection refers to measures to prevent aspiration, historically including cricoid pressure (Sellick maneuver), though its routine use is now debated.
- Placement with Proof: After the patient is fully relaxed, the endotracheal tube is placed under direct visualization. Confirmation of correct tracheal placement is paramount. Continuous waveform capnography is the most reliable method and is the standard of care. Other methods include auscultation of the chest and epigastrium, observing symmetric chest rise, and seeing condensation in the tube.
- Post-intubation Management: Once placement is confirmed, the tube must be secured firmly. The patient is connected to a mechanical ventilator, and appropriate long-term sedation and analgesia must be initiated promptly, as the paralytic agent wears off. A chest X-ray is obtained to check the tube’s depth relative to the carina.
Choosing an Induction Agent: Etomidate vs. Ketamine
For years, etomidate was avoided by some clinicians in septic and critically ill patients because of concern that its transient adrenal suppression might increase mortality, and ketamine was often promoted as the safer choice in shock. The large 2025 RSI randomized trial (Casey et al., New England Journal of Medicine) directly compared the two agents in 2,365 critically ill adults undergoing emergency intubation. In-hospital death by day 28 was not significantly different between ketamine (28.1%) and etomidate (29.1%). Notably, cardiovascular collapse during intubation was more common with ketamine (22.1%) than with etomidate (17.0%). The practical takeaway is that the feared mortality harm of etomidate was not confirmed, both agents are reasonable first-line induction choices, and the decision should be individualized to the patient (e.g., favor ketamine for bronchospasm, favor etomidate for hemodynamic neutrality) rather than driven by a blanket preference for ketamine in shock. Regardless of agent, reduce the induction dose in hypotensive patients.
Succinylcholine Contraindications and Hyperkalemia Timing
Succinylcholine causes a transient rise in serum potassium and is contraindicated when this could be dangerous: known or suspected hyperkalemia, a personal or family history of malignant hyperthermia, denervating neuromuscular disease, and the subacute phase after major burns, crush injury, or denervation/upper motor neuron injury. A key safety point is the timing of the hyperkalemia risk: it is not present in the first hours after an acute injury but develops as extrajunctional acetylcholine receptors up-regulate, becoming dangerous over the following days and peaking approximately 7-10 days after the injury, after which it can persist for months. When in doubt about this window, rocuronium is the safer paralytic.
Limitations
This calculator provides standard dose ranges using total body weight. The exact dose must be tailored to the individual patient’s hemodynamics, comorbidities, and the clinical scenario by an experienced provider — in particular, the induction dose should be reduced in shock. This tool does not replace clinical judgment.
Frequently Asked Questions (FAQ)
1. When should Ketamine be chosen over Etomidate for induction?
Both are reasonable. Ketamine is often favored for bronchospasm (it is a bronchodilator) and etomidate for its hemodynamic neutrality. The 2025 RSI randomized trial (Casey et al., NEJM) found no significant difference in 28-day in-hospital death between ketamine (28.1%) and etomidate (29.1%), and cardiovascular collapse during intubation was actually more frequent with ketamine (22.1% vs 17.0%). Etomidate’s feared mortality harm from adrenal suppression was not confirmed, so the choice should be individualized rather than a reflex preference for ketamine in shock. In any hypotensive patient, reduce the induction dose.
2. What are the major contraindications to using Succinylcholine?
Succinylcholine is contraindicated in conditions that predispose a patient to life-threatening hyperkalemia and in those with a personal or family history of malignant hyperthermia. The hyperkalemia risk after major burns, crush injury, denervation, or upper motor neuron injury is not immediate — it develops over days and peaks roughly 7-10 days after the injury, then can persist for months. It should also be avoided with known hyperkalemia and in denervating neuromuscular diseases (e.g., Guillain-Barré, multiple sclerosis).
3. Why is Vecuronium’s onset time a critical consideration?
While an effective paralytic, Vecuronium’s onset of action (2.5-3 minutes) is significantly slower than Rocuronium (60-90 seconds) or Succinylcholine (~60 seconds). This delay means it is not a true “rapid” sequence agent. Using it requires patience and may not be appropriate for patients who are rapidly desaturating or have a difficult airway, as optimal intubating conditions will not be present for several minutes after administration.
4. Why is Rocuronium dosed at 1.2 mg/kg for RSI?
A standard dose of rocuronium is around 0.6 mg/kg, which has a slower onset. For a true Rapid Sequence Intubation, a much faster onset of paralysis is required to mimic the speed of succinylcholine. Dosing rocuronium at 1.0 to 1.2 mg/kg (on total body weight) significantly shortens its onset time to 60-90 seconds, making it a suitable alternative to succinylcholine for RSI.
5. What dose of succinylcholine is used for ED RSI?
The standard emergency-department RSI dose of succinylcholine is 1.5 mg/kg using total body weight; the 1-2 mg/kg range displayed by this calculator brackets that value. Some sources use up to 2 mg/kg to ensure rapid, complete paralysis. As with all RSI drugs, confirm contraindications before use.
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📖 Sources:
- Brown CA III, ed. The Walls Manual of Emergency Airway Management. 6th ed. Philadelphia: Wolters Kluwer; 2023.
- Walls RM. Airway. In: Rosen’s Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia: Elsevier; 2023.
- Driver BE, Klein LR, Prekker ME, Cole JB, Satpathy R, Kartha G, Robinson A, Miner JR, Reardon RF. Drug Order in Rapid Sequence Intubation. Acad Emerg Med. 2019 Sep;26(9):1014-1021. PMID: 30834639.
- Casey JD, Seitz KP, Driver BE, et al. Ketamine or Etomidate for Tracheal Intubation of Critically Ill Adults. N Engl J Med. 2025 Dec 9 (online ahead of print). doi:10.1056/NEJMoa2511420. PMID: 41369227.
- U.S. Food and Drug Administration. Anectine (succinylcholine chloride) injection, Prescribing Information. 2018.
⚠️ Disclaimer:
This RSI Drug Dose Calculator is intended to assist, not replace, experienced medical personnel. All treatment decisions must be made by a qualified healthcare professional considering the individual patient’s full clinical context. Airway management should only be performed by trained individuals.
