Rapid Sequence Intubation

Airway management is among the most significant skills for an emergency specialist to understand since failure to secure a sufficient airway can result in disability or death. Rapid sequence intubation (RSI) and delayed sequence intubation are crucial for emergency airway management.
Rapid sequence intubation (RSI) is management in an airway that gives inductive instant responsiveness or induction agent and relaxation of the muscles (neuromuscular blocking agent). It is the fastest and the most efficient measure used in emergency airway control. The lack of impulsive ventilation results in a significant risk if the provider does not ventilate or intubate the patient within the shortest time possible. RSI is of particular importance to the patient with an illness, life-threatening injury, full stomach, and intact gag flex that need immediate airway control (Kenneally, Jarvie, Marshall, & Ambulance Victoria, 2012).
RSI is considered a better method of endotracheal tube intubation (ETTI) in the case of an emergency. This is because it leads to neuromuscular blockade (paralysis) and rapid unconsciousness (intubation). This is crucial in the individuals who have not fasted, and due to this, they are facing a greater risk of aspiration and vomiting. Furthermore, the main aim of RSI is to bring about intubation of the trachea with no need to utilize bag-valve-mask (BVM) ventilation, which is mostly required when trying to achieve intubating state with only sedative agents which include propofol, etomidate, and ketamine.
Modified RSI is a term which is used in some instances to describe the difference in the classic RSI approach for example titration of induction agents and ventilation during apnea. Modified approaches often trade high risks of aspiration for the other advantages such as preventing respiratory acidosis as a result of apnea from compounding increased metabolic acidosis. The main drugs used for this condition are etomidate and benzodiazepines.
Etomidate is derived from imidazole and is the sedative-hypnotic agent which is commonly used for RSI. The dominate works on the gamma-aminobutyric acid (GABA) receptor complex, resulting in a block of neuroexcitation and production of anesthesia (Kenneally, 2009). For rapid sequence intubation, etomidate is administered by intravenous push in o.3mg/kg dose. The time to effect of is between fifteen to forty-five seconds while the duration of action ranges from three to twelve minutes. Etomidate does not stimulate histamine release, and therefore it is the primary hemodynamically natural of the RSI sedative agents used.
The stability of etomidate makes it explicitly necessary medication for the intubation of a hypersensitive patient. Etomidate is also suitable for patients with intracranial in airway resistance as well as when hypotension must be avoided. The agent results in a mild rise in airway resistance, but it can be used in patients having bronchospasm.
There are several concerns with etomidate including myoclonus, adrenal suppression, and evidence of cerebral excitation after intubation. Myoclonus during RSI is minimal and brief due to concurrent injection of a paralytic agent which has no clinical significance. Etomidate reduces metabolic oxygen demand and cerebral blood flow while at the same time preserving profusion pressure in cerebral.
Benzodiazepines are also used for RSI. It causes amnesia and sedation due to their effect on the GABA receptor complex. Midazolam is benzodiazepine which acts most rapidly and is majorly used for RSI. The Midazolam induction dose is o.2 or 0.3 mg/kg. The time to effect is approximately thirty to sixty seconds while the duration of action is fifteen to thirty minutes. Like other benzodiazepines, midazolam does not give analgesia, but instead, it has an anticonvulsant effect which makes it an agent for RSI in the patients who have epilepsy (Kenneally, 2009).
The regular midazolam induction dose for RSI is 0.2 mg/kg. Midazolam results in moderate hypotension in this dosage with a standard drop in the arterial blood pressure mean in the normal individuals of ten to twenty-five percent. This possibility to induce hypotension limits is the usefulness of midazolam in case of shock or hypovolemia. If it is a must to use midazolam in such patients, a dosage of 0.1 mg/kg should be used, that will to some extent decrease the depth of sedation achieved and delay in the speed of onset, but should not heavily compromise intubation condition. For the individuals in shock, etomidate should be used due to their high hemodynamic profiles.
The main disadvantages of RSI are prolonged intubation with hypoxia, complications from the additional drugs, and precipitating crash or emergent airway. Controversy has resulted concerning various steps in RSI (Finucane, Tsui, B. C.-H, & Santora, 2011). However, RSI is the standard of care in airway management emergency medicine. RSI also is not used in patients who are apnea and unconscious. This condition is seen as a crash airway, and therefore instant bag-valve-mask ventilation, as well as endotracheal intubation with no pretreatment, paralysis, or induction, is indicated. Caution should be taken in RSI in the cases of patients having suspected difficult airway. If there is the anticipation of the difficulty, then the use of airway adjuncts such as fiberoptic intubation or an awake technique is recommended. Use of anesthesia personnel may be called upon to aid in securing the airway of a patient who is difficult to intubate is another alternative (Finucane, Tsui, B. C.-H, & Santora, 2011).
Rapid sequence intubation is a primary tool in the pre-hospital airway management, and this is one of its advantages. It is life-saving if it is used with adequate training on the proper patients. There are fewer complications and high success rates when RSI is used as compared no adjuvant medication. Furthermore, studies have revealed that there is a drastic improvement when paralytic is used. Finally, in RSI, there are several medications to choose from, and the best among them depends on patient conditions, paramedic level of training and local protocols.
Delayed sequence intubation (DSI) involves administration of certain sedative agents, which does not blunt airway reflexes or spontaneous ventilation; followed by a moment of preoxygenation before paralytic agent management.
The primary purpose of DSI is to ensure emergent intubation is safer and easier, and thereby boosting the rate of success in intubation and reduce the complications. One option that cloud ameliorate hypoxemia existing is delayed sequence intubation. The induction agent is first given to facilitate preoxygenation either by non-invasive positive pressure ventilation (NIPPV) or by a nonrebreather mask during DSI.The patient is given paralytic and intubated after a period of preoxygenation. Direct sequence intubation is essential in cases where the patient has altered psychological condition or agitation that precludes preoxygenation with NPPV mask or nonrebreather (Benumof & Hagberg, 2013). Accomplished preoxygenation by this technique will provide the patient theoretically buffer against desaturation and reserve oxygen during intubation attempt.
Another way of describing DSI is as procedural sedation. The procedure for this situation is preoxygenation effectiveness. After this process is completed, the patient can be paralyzed then intubated. Similar to procedural sedation, patients are supposed to be calm, but breathing spontaneously as well as protecting the airway (In Ignatavicius, In Workman, In Blair, In Rebar, & In Winkelman, 2016).
Ketamine is the ideal agent for the use in DSI. The administration of this drug does not require airway reflexes or blunt patient, and it provides a dissociative state. The drug allows for a preoxygenation application. A dose of between 1 and 2 mg/kg by a slow intravenous pus will make patient calm within thirty seconds. Preoxygenation will then follow in a secure, controlled manner. Preoxygenation can be achieved with NRB, or more preferably in an individual having a shunt, by use of the mask which is non-invasive mask connected to the ventilator with a continuous positive airway pressure therapy (CPAP) setting of between 5 to 15 cm water. When as saturation of more than ninety-five percent has been achieved, the patient required to breathe fiO2 oxygen for extra two to three minutes to meet the standard denitrogenation. Administration of paralytic is then done, and after an approximately one-minute apneic duration, the patient is intubated.
In patients with tachycardia or high blood pressure, the sympathomimetic results of ketamine are not desirable. Although these effects can be blunted with a little dose of labetalol or benzodiazepine, there is an availability of preferable sedation agent for tachycardia or hypertensive patients. Dexmedetomidine is an alpha-agonist, which gives sedation with no blunting of airway reflex or airway reflexes. A dose of 1mcg/kg is administered before ten minutes will enable the patient to accept preoxygenation after three to five minutes in most cases.
The main advantage of DSI is that after that administration of the sedative agent and the patient has been placed on non-invasive ventilation, there will be a drastic improvement in the respiratory parameters, and therefore the intubation can be avoided. In these situations, the sedative is then allowed to reassess and wear off the work of breathing as well as the mental status of the patient (In Shah & In Mason, 2015). If it is deemed that intubation is still needed at this moment, standard RSI is used by the administration of the conventional sedation agent which includes additional ketamine or etomidate in combination with a person with paralysis, since the patient has been already preoxygenated appropriately.
The main setback of DSI is that ketamine in some cases results in new reaction and nausea although there is no big reason to worry about it. Nausea only appears to be a challenge in few cases, and it only emerges in a dissociative state. The patients are kept sedated by the use of ketamine for an extended period (In Shah & In Mason, 2015). This period extends up to transfer of care from the emergency department (ED). Moreover, when using drugs such as ketamine, although the patient is sedated, they will mount catecholamine surge after being shocked and feel pain.
Both RSI and DS techniques that require experience training and frequent updating to maintain competence. Both techniques are very crucial in airway management. It is essential to know the drugs used in each case as well as how to administer each drug and the dosage required. Knowing the health history and condition of the patient enable on to identify the type of drug to use.

References

Benumof, J., & Hagberg, C. A. (2013). Benumof and Hagberg's Airway management. Philadelphia, PA: Elsevier/Saunders.
Finucane, B. T., Tsui, B. C.-H, & Santora, A. H. (2011). Principles of airway management. New York: Springer.
In Ignatavicius, D. D., In Workman, M. L., In Blair, M., In Rebar, C. R., & In Winkelman, C. (2016). Medical-surgical nursing: Patient-centered collaborative care.
In Shah, K., & In Mason, C. (2015). Essential emergency procedures.
Kenneally, J. (2009). MICA paramedic rapid sequence intubation. Doncaster, Vic: Ambulance Victoria.
Kenneally, J., Jarvie, I., Marshall, T., & Ambulance Victoria. (2012). Pre-hospital airway management: From basic care to rapid sequence intubation : reference text for paramedics."