Flashcards in RSI Deck (56):
What is RSI?
RSI is the virtually simultaneous administration of a sedative and a neuromuscular blocking agent to render a patient rapidly unconscious and flaccid in order to facilitate emergency endotracheal intubation and to minimize the risk of aspiration.
What could happen if a paralytic is administered without a sedative?
The patient may be fully aware of his or her environment, including pain, but unable to respond.
Inhumane, AND allows for potentially adverse physiologic responses to airway manipulation, including tachycardia, hypertension, and elevated intracranial pressure.
How does Etomidate work?
Specifically, it's a sedative-hypnotic agent that acts directly on the gamma amino butyric acid (GABA) receptor complex, blocking neuroexcitation and producing anesthesia
Etomidate typical adult dose?
More specifically, 0.3mg/kg
Etomidate time to effect?
Etomidate duration of action?
Etomidate is the most _____ _____ of the sedative agents used for RSI.
Etomidate DOES NOT stimulate this.
True or false:
Etomidate provides analgesic effects.
False, so it does not blunt the noxious stimulation of the upper airway during laryngoscopy and intubation.
Therefore, for patients in whom this is a concern (eg, patients with cardiovascular disease or elevated intracranial pressure), an opioid analgesic, such as fentanyl, is often given during the pretreatment phase of RSI
The hemodynamic stability associated with Etomidate makes it a particularly useful medication for the intubation of _____.
...as well as for patients with intracranial pathology, when hypotension must be avoided.
Etomidate causes a mild increase in _____.
...but may be used in patients with bronchospasm
The major controversy surrounding etomidate stems from the _____ _____ _____ associated with its use.
Reversible adrenocortical suppression.
A single dose of etomidate causes a transient but measurable decrease in the level of circulating cortisol that occurs in response to the administration of exogenous ACTH, although cortisol levels do not fall below the normal physiologic range. This effect does not persist beyond 12 to 24 hours.
In a nutshell, when intubating the critically ill patient with possible adrenal insufficiency, the clinician must weigh the theoretical risk of cortisol suppression against the hemodynamic instability that may be caused by alternative induction agents.
Etomidate should NOT be used as a(an) _____ or in _____ _____ _____ for maintenance of sedation after intubation.
infusion or in repeated bolus doses
How do benzodiazepines work?
Benzodiazepines cause sedation and amnesia through their effects on the gamma amino butyric acid (GABA) receptor complex.
The most rapidly acting benzodiazepine commonly used for RSI is _____.
Induction dose for Midazolam?
0.1-0.3mg/kg IV push
Midazolam's time to effect?
Midazolam's duration of action?
True or false:
Benzodiazepines provide analgesia?
False, but they do possess anticonvulsant effects, making them an effective agent for RSI in patients with status epilepticus.
In its induction dose, Midazolam causes _____.
moderate hypotension, with an average drop in mean arterial blood pressure in healthy patients of 10 to 25 percent.
*This tendency to induce hypotension limits Midazolam's usefulness in the setting of hypovolemia or shock.
For patient's in shock, _____ or _____ are suggested as induction agents.
Etomidate or Ketamine, because of their superior hemodynamic profiles.
_____ is frequently underdosed (common dose 0.05 mg/kg) when used for emergency department RSI.
Midazolam is often used for procedural sedation in much smaller doses than are required for RSI, which may contribute to underdosing.
True or false:
Midazolam can be used as an infusion for long-term sedation.
Doses of 0.05 to 0.4 mg/kg per hour IV have been shown to be safe and effective in critically ill neonates and children, including neonates undergoing extracorporeal membrane oxygenation. Dosing in intubated adults should be titrated to an endpoint of adequate sedation, preferably using a sedation scale.
True or false:
Lorazepam and diazepam are benzodiazepines used frequently for long-term sedation following intubation, but are not recommended for RSI.
Both require propylene glycol as a diluent, and there are reports of propylene glycol toxicity associated with long-term infusions.
What is Ketamine?
Ketamine is a dissociative anesthetic agent, structurally similar to phencyclidine (PCP).
What makes Ketamine unique among sedative agents?
It provides analgesia along with its amnestic and sedative effects.
Typical Ketamine dose?
Ketamine's time to effect?
Ketamine's duration of action?
How does Ketamine work?
Ketamine acts at many receptors causing a range of effects.
It is thought to stimulate the N-methyl-D-aspartate receptor at the GABA receptor complex, causing neuroinhibition and anesthesia.
It excites opioid receptors within the insular cortex, putamen, and thalamus, producing analgesia.
It stimulates catecholamine receptors and release of catecholamines leading to increases in heart rate, contractility, mean arterial pressure, and cerebral blood flow.
It decreases the production of vascular nitric oxide, diminishing its vasodilatory effect, and inhibits nicotinic acetylcholine receptors.
This drug is a good choice for "awake" intubation attempts, when laryngoscopy is performed on a patient who is moderately sedated and topically anesthetized but not paralyzed due to concerns about a difficult airway.
Ketamine, because it preserves respiratory drive and has both a quick onset of action and analgesic properties.
Ketamine causes sympathetic _____.
Ketamine: good or bad choice for hypotensive patients?
Ketamine is among the most hemodynamically stable of all of the available sedative induction agents, making it an attractive choice for hypotensive patients requiring RSI.
*However, according to limited observational evidence and clinical experience, patients who are depleted of catecholamines due to their underlying disease or otherwise at increased risk of shock have a blunted sympathetic response, and may even develop hypotension, following administration of ketamine for RSI.
Theoretically, ketamine causes bronchodilation by stimulating the _____ _____ _____.
release of catecholamines.
Also, limited evidence from animal studies suggests the drug may also have direct bronchodilatory effects.
Controversy persists regarding the use of ketamine in patients with _____ _____ due to concerns about _____ _____ _____.
head injuries due to concerns about elevating intracranial pressure (ICP).
Opponents emphasize that ketamine can cause a rise in ICP through sympathetic stimulation, potentially exacerbating the condition of such patients. However, when ketamine is used with a GABA agonist, this rise in ICP may not occur. Furthermore, by increasing cerebral perfusion, ketamine may benefit patients with a neurologic injury.
BASICALLY, evidence suggesting ketamine elevates ICP is weak, and evidence that harm might ensue is weaker. We believe ketamine is an appropriate induction agent for RSI in patients with suspected ICP elevation and normal blood pressure or hypotension. In patients with hypertension and suspected ICP elevation, ketamine should be avoided because of its tendency to further elevate blood pressure.
What is Propofol and how does it work?
Propofol is a highly lipid-soluble, alkylphenol derivative that acts at the GABA receptor causing sedation and amnesia. Sedation occurs through direct suppression of brain activity, while amnesia appears to result from interference with long-term memory creation.
Propofol induction dose?
Propofol's time to effect?
Propofol's duration of action?
True or false:
Propofol does not provide anesthesia.
Propofol does not provide anesthesia.
_____ reduces airway resistance and can be a useful induction agent for patients with bronchospasm undergoing RSI
Its neuroinhibitory effects make Propofol a good induction agent for patients with _____ _____, provided they are hemodynamically stable.
Propofol suppresses sympathetic activity, causing myocardial depression and peripheral vasodilation. A decrease in mean arterial pressure (MAP) caused by propofol can reduce cerebral perfusion pressure, thereby exacerbating a neurologic injury. The usual decrease in MAP is approximately 10 mmHg.
Propofol does not prolong ________, unlike some other anesthetic agents.
the QT interval
Serum triglycerides and serum lipase _______ during propofol infusions.
Although the manufacturer lists _____ or _____ allergies as contraindications to the use of propofol, significant allergic reactions to the newer preparation of the drug appear to be rare.
egg or soybean
________ are no longer readily available nor widely used as induction agents for intubation.
They venodilate with negative cardiac inotropic effects, and can induce profound hypotension in the doses used for induction of anesthesia. Clinicians must exercise great care when using it in hemodynamically unstable patients or patients prone to hypotension, such as the elderly.
Thiopental causes histamine release and can induce or exacerbate bronchospasm. Therefore, thiopental should not be used in patients with reactive airway disease.
Thiopental and methohexital suppress white blood cell recruitment, activation, and activity. These immunosuppressive effects make barbiturates poor induction agents in the setting of sepsis.
How do barbiturates work?
The ultrashort-acting barbiturates interact with the barbiturate component of the GABA receptor complex, causing profound amnesia and sedation.
What was the most commonly used barbiturate for RSI?
Do barbiturates provide analgesia?
No, they do not.
Head injury or stroke:
In the patient with potentially elevated intracranial pressure (ICP) from head injury or stroke or other conditions, ___________ must be maintained to prevent secondary brain injury.
CHOICE OF INDUCTION AGENTS?
-ADEQUATE CEREBRAL PERFUSION PRESSURE must be maintained to prevent secondary brain injury. (This means avoiding significant elevations in ICP and maintaining adequate mean arterial pressure).
-ETOMIDATE or KETAMINE
(However, if signs of cerebral herniation are present prior to intubation, we suggest using etomidate and avoiding ketamine)
*Midazolam and propofol have been used in head-injured patients, but before doing so the risk of hypotension-induced brain injury must be considered
Suggested induction agents for status epilepticus?
Status epilepticus — We suggest PROPOFOL or, alternatively, ETOMIDATE be used for RSI of patients in status epilepticus.
Propofol is a potent anticonvulsant, but dosage must be carefully calculated to avoid dose-dependent hypotension.
Etomidate can cause myoclonus, and has a slightly higher rate of EEG-documented seizure activity compared with other medications, but may be used for RSI in status epilepticus when the patient manifests hemodynamic compromise. Etomidate use for RSI requires initiation of appropriate anti-convulsant treatment as soon as is feasible following successful intubation.
Midazolam may be used for induction, but care must be taken to use doses appropriate for RSI.
We suggest ketamine NOT be used because of its stimulant effects.
Suggested choices of induction agents for hemodynamically stable patients with severe bronchospasm requiring intubation include _______ and _______.
And for hemodynamically unstable/hypotensive patients? ________ and ________.
KETAMINE and PROPOFOL, because of their bronchodilatory properties. (Etomidate and midazolam are acceptable alternatives)
Hemodynamically unstable/hypotensive patients: KETAMINE or ETOMIDATE.
None of these agents causes histamine release.
Choice of induction agents for cardiovascular disease?
The hemodynamic stability it provides and the absence of induced hypertension make it preferable to other sedatives.
Choice of induction agents for patients in shock?
KETAMINE or ETOMIDATE
Ketamine causes a sympathetic surge that may augment endogenous catecholamines but may also elevate intracranial pressure. Etomidate has been scrutinized because of its transient suppression of endogenous cortisol. Both agents cause a small drop in MAP in patients with severe hypotension, but less than other sedative agents.
What is a "sedated look" or "awake look"?
Where the patient receives a full induction dose of a sedative agent, but no neuromuscular blocking agent (which is advised if the clinician anticipates a difficult intubation which may preclude successful RSI).
In general, the use of topical anesthesia (eg, nebulized 4 percent lidocaine) along with moderate sedation allows for a look into the airway, while enabling the patient to maintain respiratory drive and protective airway reflexes and allows the practitioner to verify that laryngeal structures are visible, before committing to paralysis.
*KETAMINE is popular for this because it allows the patient to maintain respiratory drive while providing analgesia, amnesia, and sedation.