If one of us is not already at the bedside, pharmacists at my institution are frequently called by critical care providers to assist with intubation procedures in critically ill patients.
In this episode I’ll review the pharmacists’ role and expectations during intubation of critically ill patients.
We’ll cover the following scenarios in this episode:
1. Crash airway
2. Rapid sequence intubation
3. Delayed sequence intubation
4. Difficult airway predicted
5. Awake airway
6. Failed airway
1. Identifying and predicting patient and provider needs
2. Preparing in advance to meet those needs
A crash airway exists when the patient is in cardiac or respiratory arrest or is otherwise near death.
Endotracheal intubation is attempted without medications.
If the patient is not relaxed, a single dose of a paralytic (usually succinylcholine) may be given. Use 2mg/kg for this indication (go big or go home dosing strategy).
Rapid sequence intubation (RSI)
RSI is described as occurring in 7 phases:
4. Paralysis with induction
7. Post intubation
In this phase the first thing I do is identify the provider’s preference for medications, and I will make suggestions on what to use if I see a reason to do so.
A general rule of thumb I use is to obtain double the amount of medication the physician says they want. Nothing is worse than having to run to the med room to get more induction agent after the procedure has started.
I use tape to label the syringes as it is always in my pocket or on the unit.
Preoxygenation is critical to maximize the “safe apnea time” for the patient. This is the time the provider has to place the airway after the patient stops breathing and before their O2 saturation drops to dangerous levels. This may be 8 minutes for a healthy adult, or less than 4 minutes for a critically ill or obese adult.
In this phase there is not much for the pharmacist to do so I continue with preparing / labeling if needed. If I have time, I lay several blank pieces of tape out on a table so that I have labels ready to go if additional drugs are called for.
In the ICU I rarely use these pretreatment methods but I included them here as they are more common in the emergency department.
Pretreatment involves giving lidocaine and or fentanyl to prevent known complications of intubation in at risk patients. There are 3 main reasons to use pretreatment:
1. Reactive airway disease
Give lidocaine 1.5mg/kg IV to prevent bronchospasm.
2. Elevated intracranial pressure (ICP)
Give lidocaine 1.5mg/kg IV to mitigate increased ICP from airway manipulation AND fentanyl 3mcg/kg IV to mitigate catecholamine surge from pain due to intubation.
3. Cardiovascular or other conditions when an acute rise in blood pressure or heart rate must be avoided
Give fentanyl 3mcg/kg IV to mitigate catecholamine surge from pain due to intubation.
Paralyze plus induction
This is supposed to occur simultaneously, but usually is given sequentially through the same IV line.
I prefer the induction medication be given first in case something happens to the IV line.
There are 2 realistic options:
1. Succinylcholine 1.5 mg/kg IV
2. Rocuronium 1.2 mg/kg IV
If you haven’t heard episode 14 yet where I discuss these two options head-to-head, be sure to check it out!
There are 3 realistic options:
1. Propofol 1.5 mg/kg IV
I think this is a fine choice if the patient is not very sick and has good cardiovascular reserve. Expect it to cause some hypotension/bradycardia, more so the sicker the patient is.
2. Ketamine 1.5 mg/kg IV
I think this is the best choice to use if the patient is sick or hemodynamically unstable. Remember it is an on/off induction agent and should be subjected to the go big or go home dosing strategy.
3. Etomidate 0.3 mg/kg IV
Use this if they are sick and the provider is not familiar with ketamine. It is tough to go wrong with etomidate. Expect this to be hemodynamically neutral. Some providers think even 1 dose of etomidate can cause adrenal insufficiency but I agree with Rosen’s Emergency Medicine and the cochrane reviewers that this is not likely a concern.
A quick note on dosing – no patient was ever hurt by rounding up the dose for any RSI medication. The consequences of too little medication far outweigh the consequences of too much in this scenario so don’t be stingy with your dosing!
Position the patient for intubation
Paralyzing the patient before they are in position for intubation makes me nervous, but this is where the experts put it in the algorithms.
During this phase I watch/listen for patient or provider needs such as an unexpected difficult airway, hemodynamic changes, or inadequate sedation/paralysis.
Post intubation management
While the rest of the care team is confirming tube placement and gas exchange, I believe the pharmacist should be immediately focused on the continued sedation and comfort of the patient.
Obtaining continuous sedation infusions can be time consuming so I am usually asking for some midazolam (0.05mg/kg or more) and fentanyl (1mcg/kg or more) IV boluses to be given while the continuous sedation regimen is selected and obtained.
Hypotension often occurs following emergency intubation. Venous return is reduced by the positive pressure in the intrathoracic cavity that the ventilator induces. The initial treatment for this is a saline or lactated ringers bolus followed by a norepinephrine infusion if needed. While push dose pressors are tempting to use (see episode 4) I consider this unnecessary if the pharmacist has had time to properly prepare ahead of time with a liter of normal saline, a bag of norepinephrine, IV tubing and 2 IV pumps.
Delayed sequence intubation (DSI)
DSI is proposed for when the patient can’t tolerate preoxygenation (usually due to agitation).
DSI is essentially procedural sedation with 1.5mg/kg IV ketamine so that the patient can tolerate the “procedure” of preoxygenation. RSI then proceeds when preoxygenation is complete. Ketamine is chosen because the patient will be sedated but maintain respirations with this drug.
A criticism of DSI by some is that it is not well studied and only has case series and case reports to support its use.
This technique is about as well studied as parachute use to prevent death and major trauma from gravitational challenge. Like I mentioned in episode 1, I’ll take the parachute anytime!
Difficult airway predicted
Predicting a difficult airway is not necessary for a pharmacist but knowledge of how to do so can be obtained by reviewing Rosen’s Emergency Medicine chapter on Airway Management or any number of other resources.
In this setting the patient may be sedated more like procedural sedation without the use of paralytics. Induction agents may be titrated and the patient may only reach a moderate/deep level of sedation.
A glidescope is always used for this at my institution.
A majority of the airways placed in my med/surg community ICU appear to fall under this category with paralytics being withheld and sedatives being titrated.
I’d love to hear from other critical care pharmacists whether you find the provider withholding paralytics often during intubation in the ICU – send an email to firstname.lastname@example.org and let me know.
I can only remember an awake fiberoptic intubation once in an obese patient with myasthenia crisis. After several failed attempts we administered a 1mcg/kg IV bolus over 10 minutes of dexmedetomidine and the patient was successfully intubated.
A failed airway exists when further attempts at endotracheal intubation are unlikely to result in an airway being placed.
A laryngeal mask airway or cricothyrotomy may be attempted in this case.
Other than possibly obtaining local anesthetic for use in the cricothyrotomy, the role of the pharmacist in this scenario is to make preparations to treat the patient should they go into cardiac arrest.
If you are interested, here is an amazing video and analysis of an “elective” cricothyrotomy in a patient who could not be endotracheally intubated.
A note on obese patients
I recently listened to this excellent podcast discussing the emergency management of obese patients. There is a lot of information in this podcast about airway management and drug dosing in obese patients and I would highly recommend you listen to it!
If you like this post, check out my book – A Pharmacist’s Guide to Inpatient Medical Emergencies: How to respond to code blue, rapid response calls, and other medical emergencies.