Rapid sequence induction
| Rapid sequence induction | |
|---|---|
| Intervention |
Rapid Sequence Induction (RSI) is a medical procedure involving the expeditious induction of general anesthesia and subsequent intubation of the trachea. RSI is generally used in an emergency setting or for patients who have an increased risk of aspirating stomach contents into the lungs.[1] If not performed properly, or if tracheal intubation is not accomplished within a short period of time (usually less than 2 minutes), the patient could suffer extreme morbidity or even death from hypoxia.
Contents |
[edit] Common medications
Commonly used medications during a rapid sequence induction:
[edit] Technique
RSI refers to the pharmacologically induced sedation and neuromuscular paralysis prior to intubation of the trachea. The technique is a quicker form of the process normally used to induce general anesthesia. With standard intravenous induction of general anesthesia, the patient typically receives an opioid, such as fentanyl, and then a drug to induce unconsciousness (commonly propofol). At this point, the patient is manually ventilated for a short period of time before a neuromuscular blocking agent (for example succinylcholine or rocuronium) is administered and the patient is intubated. During rapid sequence induction, the patient still receives the IV opioid. However, the difference lies in the fact that the induction drug and blocking agent are administered in rapid succession with no time allowed for manual ventilation. In either case, the endotracheal tube is placed shortly after onset of action of the blocking agent. Medications are utilized to allow rapid placement of an endotracheal tube between the vocal cords, while the cords are being visualized with the aid of a laryngoscope. Once the endotracheal tube has been passed between the vocal cords, a cuff is inflated around the tube in the trachea and the patient can then be artificially ventilated.
RSI involves preoxygenating the lungs with a tightly-fitting oxygen mask, followed by the sequential intravenous administration of predetermined doses of a sleep-inducing drug and a rapid-acting neuromuscular blocking agent.[2] Commonly used hypnotics include thiopental, propofol and etomidate. Commonly used neuromuscular blocking agents used include succinylcholine and rocuronium.[3] The neuromuscular blocking agents paralyze all of the skeletal muscles, most notably and importantly in the oropharynx, larynx, and diaphragm. Opioids such as fentanyl may be given to attenuate the responses to the intubation process (accelerated heart rate and increased intracranial pressure). This is supposed to have advantages in patients with ischemic heart disease and those with brain injury (e.g. after traumatic brain injury or stroke). Lidocaine is also theorized to blunt a rise in intracranial pressure during laryngoscopy, although this remains controversial and its use varies greatly. Atropine may be used to prevent a reflex bradycardia from vagal stimulation during laryngoscopy, especially in young children and infants. Despite their common use, such adjunctive medications have not been demonstrated to improve outcomes.[4]
One important difference between RSI and routine tracheal intubation is that the practitioner does not manually assist the ventilation of the lungs after the onset of general anesthesia and cessation of breathing, until the trachea has been intubated and the cuff has been inflated. Another key feature of RSI is the application of manual pressure to the cricoid cartilage, often referred to as the "Sellick maneuver", prior to instrumentation of the airway and intubation of the trachea.[1]
[edit] Additional considerations
The clinician that performs RSI must be skilled in tracheal intubation and also in bag valve mask ventilation. Alternative airway management devices must be immediately available, in the event the trachea cannot be intubated using conventional techniques. Such devices include the combitube and the laryngeal mask airway. Invasive techniques such as cricothyrotomy must also be available in the event of inability to intubate the trachea by more conventional techniques.
[edit] Controversy
Since the introduction of RSI, there has been controversy regarding virtually every aspect of this technique, including:[5]
- choice of intravenous hypnotic agents as well as their dosage and timing of administration
- dosage and timing of administration of neuromuscular blocking agents
- avoidance of manual ventilation before tracheal intubation
- optimal position and whether the head-up, head-down, or horizontal supine position is the safest for induction of anesthesia in full-stomach patients
- application of cricoid pressure (the Sellick maneuver)
[edit] References
- ^ a b Stone DJ and Gal TJ (2000). "Airway management". In Miller, RD. Anesthesia, Volume 1 (5th ed.). Philadelphia: Churchill Livingstone. pp. 1414–51. ISBN 9780443079955. http://www.amazon.com/Anesthesia-Fifth-5th-Volumes-Included/dp/B003K8IDK8/ref=sr_1_4?ie=UTF8&s=books&qid=1283816205&sr=8-4.
- ^ Suresh MS, Munnur U and Wali A (2007). "Chapter 32: The patient with a full stomach". In Benumof, JL. Benumof's Airway Management: Principles and Practice (2nd ed.). Philadelphia: Mosby-Elsevier. pp. 752–82. ISBN 9780323022330. http://books.google.com/?id=uUVYjVUexKUC&printsec=frontcover&dq=Benumof's+Airway+Management:+Principles+and+Practice#v=onepage&q&f=false.
- ^ Pousman, RM (2000). "Rapid Sequence Induction for Prehospital Providers". The Internet Journal of Emergency and Intensive Care Medicine 4 (1). http://www.ispub.com/ostia/index.php?xmlFilePath=journals/ijeicm/vol4n1/rapid.xml#documentHeading-VI.Pharmacology.
- ^ Neilipovitz, DT; Crosby, ET (2007). "No evidence for decreased incidence of aspiration after rapid sequence intubation". Canadian Journal of Anesthesia 54 (9): 748–64. doi:10.1007/BF03026872. PMID 17766743. http://www.cja-jca.org/cgi/content/full/54/9/748.
- ^ El-Orbany, MI; Connolly, LA (2010). "Rapid Sequence Induction and Intubation: Current Controversy". Anesthesia & Analgesia 110 (5): 1318–25. doi:10.1213/ANE.0b013e3181d5ae47. http://www.anesthesia-analgesia.org/content/110/5/1318.full.pdf.
