Pediatric emergency medicine trisk 44

the one-way valve in self-inflating devices Newer approaches include the use of apneic oxygenation to increase safe apnea time Data are currently limited, particularly in children; however, many PEM clinicians are currently employing this technique The optimal flow rate in children has not been established, but rates of to L/min in infants, to 15 L/min in school-age children, and 15+ L/min in adolescents are likely beneficial with minimal risk of harm Much higher rates have been utilized in fasted patients in the OR setting PATIENT POSITIONING Bag-valve-mask (BVM) ventilation and TI are generally performed with the patient in the supine position There are instances in which upright or prone positioning has theoretical anatomic airway structure advantages for BVM ventilation Some newer studies conclude that intubation success rates are higher when using head-elevated positioning, also called ramping Here, the upper body is included and the head extended, similar to sniffing position Much of this data come from adult literature, however limited pediatric experience is supportive The optimal intubation patient position in pediatrics might continue to evolve with further study and dissemination of this information MEDICATIONS Sedatives Sedatives used for intubation should render the patient rapidly unconscious ( Table 8.3 ) They should ideally have minimal adverse effects on hemodynamics or intracranial pressure (ICP); however, all sedatives have the potential for adverse effects and efficacy limitations The optimal sedative depends on the clinical situation and appropriately weighs benefits against risks TABLE 8.3 SEDATIVES Medication Dose Benzodiazepines (midazolam, lorazepam) Narcotics (fentanyl) Ketamine Etomidate Propofol 0.2–0.3 mg/kg 1–2 mcg/kg 1–3 mg/kg 0.3 mg/kg 1–4 mg/kg Ketamine is a dissociative anesthetic with reliable and rapid onset It has the beneficial effects of augmenting hemodynamics, making it the theoretical drug of choice for patients who are at risk for cardiovascular depression Ketamine is commonly used as a procedural sedative/analgesic since it preserves airway reflexes and respiratory drive, but its adverse effects include vomiting, laryngospasm, and emergence delirium In the context of RSI, these adverse effects have less significance Ketamine increases oral secretions (a sialogogue) The coadministration of atropine is often recommended to counter this, however the onset of this effect takes 15 to 20 minutes and therefore is unlikely to impact laryngoscopy and intubation Ketamine maintains cardiovascular responses by blocking reuptake of catecholamines Earlier studies have suggested that ketamine increases ICP This led to the widespread belief that ketamine is relatively contraindicated in head trauma, which is a frequent indication for RSI Newer studies and analyses suggest that ketamine’s effect on ICP is variable and that it benefits cerebral perfusion pressure and systemic arterial pressure Ketamine is reported to have bronchodilator properties which favors its selection in status asthmaticus; however, data are limited Etomidate provides reliable rapid-onset sedation, reliable pharmacokinetics, and cardiovascular stability It has no effect in ICP While some sources have described etomidate as having cerebroprotective properties, the primary source of proof for this is difficult to find Some nonrandomized trials have demonstrated poorer outcomes in patients receiving etomidate This applies to both single-use etomidate for ED RSI and for longer-term use of etomidate in the ICU Etomidate use was associated with greater hypotension in septic patients, a higher rate of ARDS and multiple organ dysfunction in severely injured trauma patients, trends toward longer ventilator courses and hospital stays, and an increase in mortality These outcomes are commonly attributed to the known suppression of adrenal function following administration of etomidate However, more recent randomized trials and meta-analyses, primarily using data from adults, have not shown difference in mortality or hospital utilization when using etomidate Nonetheless, PALS and other guidelines consistently raise caution on its use in patients with septic shock Propofol is a commonly used sedative in general, yet its role in ED RSI is unclear Propofol is a potent vasodilator and myocardial depressant, resulting in a significant risk of hypotension which makes it unsuitable for hypovolemic patients, children in shock, or patients in whom the maintenance of cerebral perfusion is essential While some sources have described propofol as having cerebroprotective properties, the primary source of proof for this and substantiation in human studies are difficult to find Benzodiazepines are generally considered to be safe with anticonvulsant and amnestic effects, reversibility (flumazenil), and less cardiovascular depression However, its dosing is variable in that a standard dose of a benzodiazepine (e.g., 0.1 mg/kg) does not reliably result in inducing unconsciousness in a child Higher doses (e.g., 0.3 to 0.4 mg/kg) are often required for induction and have a slower onset which places the patient at higher cardiovascular risk It should be noted that all sedatives can result in cardiovascular collapse in patients with marginal cardiovascular function such as in hypotension, hypovolemia, myocardial dysfunction, and sepsis In severe hemodynamic compromise (e.g., hemorrhagic shock, septic shock), consider that a very low dose or no sedative administration might be preferable, especially if the patient is already unconscious, to prevent cardiovascular collapse Dexmedetomidine, remifentanil, and combinations of propofol/remifentanil have been studied in RSI outside of the ED More studies are needed to determine their role in RSI in pediatric emergency medicine Neuromuscular-Blocking Agent (Paralyzing Agent) The NMBA used to facilitate intubation should render the patient completely flaccid, negating the effects of laryngeal reflexes on laryngoscopy and passage of an ETT ( Table 8.4 ) The ideal agent should have a rapid-onset and short duration to allow the rapid return of spontaneous ventilation in case the patient cannot be successfully intubated However, return of spontaneous ventilation is frequently not a sufficient “rescue” given the patient is generally being intubated for significant airway/ventilation impairment Succinylcholine is often considered the standard since it is the oldest and has the longest track record of use It has a rapid-onset time of 30 to 60 seconds and a duration of to minutes It is a “depolarizing” paralyzing drug, causing muscle fasciculations prior to the onset of paralysis This can cause muscle pain in muscular patients, myoglobin release (myoglobinuria), potassium release (hyperkalemia), histamine release, and a higher risk of malignant hyperthermia It can result in transient bradycardia, particularly when used with inhaled anesthetics; atropine premedication is sometimes recommended to minimize this effect Succinylcholine carries a “black box” warning of hyperkalemic cardiac arrest that results from a series of children with unknown skeletal muscle myopathies This is rare and succinylcholine remains in widespread use in pediatrics TABLE 8.4 NEUROMUSCULAR-BLOCKING AGENTS (PARALYTICS) Medication Dose Succinylcholine Rocuronium Vecuronium Cisatracurium 1–2 mg/kg 0.6–1.2 mg/kg 0.1–0.2 mg/kg 0.1–0.2 mg/kg Nondepolarizing NMBAs not cause fasciculations or associated side effects Rocuronium is the most frequently used drug from this class for RSI When used at higher dose (1.2 mg/kg), it has been shown to achieve equivalent intubating conditions in the same time frame as succinylcholine However, it has a duration of 30 to 45 minutes or longer Rocuronium’s longer duration is often cited as a disadvantage However, newer considerations make the longer duration an advantage over succinylcholine in difficult intubations during which the duration of succinylcholine has elapsed, resulting with the return of muscle tone, movement, and risk of active regurgitation/aspiration With rocuronium, paralysis is maintained and the patient can be bag-mask ventilated for another intubation attempt Additionally, maintenance of the paralysis is preferable for imaging, ventilator management, vascular access, etc The need for the early reversal of rocuronium paralysis is occasionally beneficial, either to allow return of spontaneous respiration if intubation is not successful, or to allow return of a neurologic examination Reversal can be accomplished with sugammadex NMBAs with longer durations require maintenance of sedation to avoid conscious paralysis This can occur since neuromuscularly blocked patients not prompt the clinician for the need for sedation Therefore, once TI is secured, the clinician must take the initiative to maintain appropriate sedation Adjunctive Agents Atropine Atropine reduces the risk of bradycardia which can result from laryngoscopy or succinylcholine use, a physiologic phenomenon more commonly observed in infants and younger children Atropine reduces oral secretions if ketamine is to be given, although the antisialogogue activity may take 15 to 20 minutes to take effect  ... studied in RSI outside of the ED More studies are needed to determine their role in RSI in pediatric emergency medicine Neuromuscular-Blocking Agent (Paralyzing Agent) The NMBA used to facilitate intubation... unknown skeletal muscle myopathies This is rare and succinylcholine remains in widespread use in pediatrics TABLE 8.4 NEUROMUSCULAR-BLOCKING AGENTS (PARALYTICS) Medication Dose Succinylcholine