Emergency Bear Treats: PEMDoc Pearls: RSI and Special Airway Equipment

by Kaynan Doctor, Children's National

Hi everyone, here are some summary pointers from our conference on Rapid Sequence Intubation (RSI) and SIM airway at CNMC this past thursday :

Rapid Sequence Intubation

By Dewesh Agrawal

Contraindications to Rapid Sequence Intubation: Arrested Patient

Relative contraindications to RSI: anatomical barriers that may reduce success of intubation and upper airways obstruction

Relative Contraindications to bag-valve mask ventilation: Diaphragmatic hernia, asthma or any tamponade physiology e.g. Pneumothorax

Patients with Hunter’s and Hurler’s are known to have difficult airways; do not perform RSI without an anesthesiologist present

Useful equations:

Weight in kg (between 1 and 10 years): 8 or 10 + [age (yrs.) x2]

ETT tube size 4 + age/4

Foley or NG/OG 2x ETT

Depth of ETT 3 x ETT

Chest tube size = 4 x ETT

Adult male average ETT size 8.0

Adult female average ETT size 7.5

General rule of thumb with a medical alert or trauma: GCS≤8 intubate

Cricoid Pressure or the Sellick maneuver has now fallen out of favor as a definitive method reducing aspiration; studies have shown that the esophagus tends to get displaced but not occluded. The Sellick maneuver is however still useful for optimizing visualization of the cords.

Premedications for RSI

Atropine

Children < 1 year

Children < 5 years of age receiving succinylcholine

Older children needing 2^nd dose of succinylcholine

Children receiving ketamine for RSI (as ketamine is a sialagogue)

Dose 0.02 mg/kg IV (maximum single dose 0.5mg

IV given 1-2 minutes prior to intubation - give it sooner rather than later

Lidocaine

Optional for kids with increased ICP and no longer mandatory for a head injury patient

1-2 mg/kg IV given 2-3 minutes prior to intubation

Induction Agents

Etomidate

Sedative of choice in patient with multisystem trauma, hypotension or head injury

Advantages: Induction within 15 seconds, decreases intracranial pressure and causes minimal cardiovascular depression

Disadvantages: Very short acting (4-10 minutes) so need to supplement with additional agents e.g. fentanyl and midazolam. Avoidance in septic shock; causes transient adrenal suppression

Dose: 0.2 to 0.4 mg/kg/ IV

Midazolam

Advantages: Rapid onset

Disadvantages: Cardiodepressant, inconsistent effect

Dose: May need to give as high as 0.3 mg/kg to achieve adequate sedation (which can take up to 2-3 minutes) for RSI (maximum dose 2mg)

Ketamine

Sedation of choice for RSI in Asthmatics (catecholamine release results in bronchodilatation)

Advantages: Profound sedation, analgesia and amnesia

Disadvantages: Contraindicated in schizophrenics, Hypertensive agent (use with caution in patients with raised ICP), sialagogue, emetic, causes laryngospasm (this would not be a concern with RSI as ultimately you would paralyzing your patient),

Propofol (not available to PEM physicians at CNMC)

Advantages: Rapid onset, short duration, decreases ICP, anti-emetic

Disadvantages: Hypotension, injection site pain,

Dose: 1-4mg/kg

Fentanyl

Advantages: blunts sympathetic response to intubation and may be ideal for coronary artery disease patients or those with raised ICP

Disadvantages: hypotensive, Rapid infusion of an overdose or multiple repeated doses of fentanyl can result in rigid chest syndrome (treatment is with paralysis with succinylcholine and cannot be revered with naloxone).

Dose: 3 to 5 mcg/kg

Thiopental

No longer available in the US due to risks of lethal injection

Advantages: Known to have had a rapid onset, reduces ICP

Disadvantages: Potent cardiodepressant, histamine release

Clinical Scenarios for RSI Induction:

Hypotensive patient: Etomidate/ketamine

Increased ICP: - Etomidate/fentanyl/propofol/thiopental (previously), Ketamine with caution

Status asthmaticus: – ketamine

Status epilepticus: – Midazolam/ thiopental (previously)

Septic shock: - Ketamine

Paralytic agents

Succinylcholine

Drug of choice in acute trauma

Side effects - bradycardia, asystole, hyperkalemia Increased ICP, myalgia, hyperthermia, prolonged paralysis and excessive salivation.

Multiple contraindications which include: Rhabdomyolysis, crush injury, Trauma> 48 hours old, malignant hyperthermia, muscular dystrophy, paraplegia, myotonia, pseudocholinesterase deficiency, penetrating eye trauma, significant neuromuscular disease, renal failure, hyperkalemia,

Dose

2mg/kg for a infant

1.5 mg/kg for a child

1 mg/kg for an adult

Rocuronium

Most frequently used non-depolarizing neuromuscular blocking agent for pediatric RSI and is used when succinylcholine is contraindicated.

Advantages: fast onset and minimal CV effects

Supplied as a powder that needs to be prepared

Dose 0.6 to 1.2mg/kg IV (suggested dose 1mg/kg IV)

Dewesh Agrawal is a PEM attending at CNMC and also the Pediatric Residency Director

SIM Airway

with Karen O'Connell and Pavan Zaveri

Landmarks for a cricothyroidotomy:

Obtained from from King C., Henretig FM, Textbook of Pediatric Emergency Medicine Procedures, Lippincott, Williams and Wilkins 2008

There are several ways to set up the equipment for a cricothyroidotomy, initially you want to establish the airway by placing an angiocath/cricothyroidotomy tube (yellow) attached to a fluid filled syringe through the cricothyroid membrane. Draw back to see bubbles of air, which would indicate that you are in the trachea.

Karen O'Connell described one method of hardware connection: You can then attach a 3.0 ETT tube distal end /adapter/connector to the angiocath/cricothyroidotomy tube and attach a nebulizer aerochamber to this combination (shown in blue) . Then attach a 5.5 ETT tube adapter to the other end of the aerochamber. Airway tubing can then be attached to this apparatus allowing for oxygenation ( see below)