Online Journal Club December 2013: Delayed Sequence Intubation (DSI)

CASE TO CONSIDER:

A 50 yo with history of heart failure presents with increased work of breathing and fever.  

BP 110/70, HR 90, RR 30 Saturation 77%

Place on nasal cannula patient swats it away and is using accessory muscles.  Unable to place mask or nc on patient 2/2 altered mental status.  You plan to intubate.

Would you consider delayed sequence intubation?

Wait, what is delayed sequence intubation?!?!?!?

Article Link: http://www.annemergmed.com/article/S0196-0644(11)01667-2/fulltext

Article Review:

PREOXYGENATION, REOXYGENATION, AND DELAYED SEQUENCE INTUBATION

IN THE EMERGENCY DEPARTMENT

Scott D. Weingart, MD

Overview

Delayed sequence intubation is a procedure where the focus is pre oxygenation. There is very little published evidence for safety/efficacy.

Pathophysiology of Hypoxemia

In the ED the major cause for hypoxemia is physiologic shunt.  This is caused by areas of the alveoli blocked from conducting oxygen.  Causes include: pneumonia, atelectasis, pulmonary edema, mucous plugging, ARDS.   In addition, perfusion without ventilation leads to mixing of deoxygenated venous blood with arterial blood.  In shock, venous blood arrives at lungs with lower saturation therefore requires more exposure to oxygen but in injured lungs this does not occur

Standard Preoxygenation in the ED

If the saturation is less than 90% prior to intubation saturation will fall much quicker during intubation due to oxyhemoglobin dissociation curve.  This cannot be corrected with BVM cannot unless PEEP adaptor is used.

• NRB provides 70-80% fiO2
• If the saturation is  less than 95% on NC at 6L/min they have some shunting
• If the saturation is less than 95% on NRB then they have  moderate to severe shunting
• You can preoxygenate with CPAP or BVM with PEEP valve attached in high risk patients
• Recall with good jaw thrust you should be able to maintain saturation  greater than 98% in apneia with no breaths

How can we better pre-oxygenate and prevent rapid desaturation during intubation?

Delayed Sequence Intubation

1. Identify an agitated patient requiring intubation
2. Administration induction agent, ideally ketamine 1- 1.5 mg/kg
• In patients with high BP or tachycardia can counter sympathomimetic effects of ketamine with benzos or labetalol
3. If SpO2 is less than 95% then use CPAP or BMV with PEEP at 5-15 cmH2)
• This will take 2-3 minutes but may take greater than 10 minutes
4. After saturation of 100% is achieved patient can breath high fiO2 for 2-3 minutes to acheive denitrogenation of the alveoli
5. Administer neuromuscular blocker, wait 45-60 seconds
6. Perform apneic oxygenation using 15 L/min O2 via nasal prongs +/- continued CPAP
7. Intubate patient

The main purpose of Delayed Sequence Intubation 

is to obtain BETTER PREOXYGENATION.

Consider it.  Think about it.  Talk about it…Try it. 

You might even save an intubation!

Here is a great video review by Dr Minh Le Cong from Life in the Fast Lane:

http://prehospitalmed.com/2013/01/26/delayed-sequence-intubation-or-dci-deadly-critical-intubation-nope-that-doesnt-sound-better/

Review Questions

1. The goal of delayed sequence intubation is to avoid intubation

a. True

b. False

2. A NRB provides ____ %O2

a. 90-100%

b. 70-80%

c. 50-60%

d. <40 span="">

3. What is the first agent that should be used for delayed sequence intubation?

a. Propofol

b. Ketamine

c. Etomidate

d. Versed

4. In patients with hypertension or tachycardia what agent should be used?

a. No change

b. Propofol

c. Ketamine + benzodiazepine

d. Etomidate

5. What are the steps for delayed sequence intubation?

a. Identify patient with hypoxia improving with nc  → administer Ketamine → preoxygenate with CPAP → administer paralytic → intubate

b. Preoxygenate with CPAP → administer Ketamine → administer paralytic → Intubate

c. Identify delirious patient with hypoxia → administer Ketamine → administer paralytic → intubate

d. Identify delirious patient with hypoxia → administer Ketamine → preoxygenate with CPAP → administer paralytic → intubate

Answers

1. b
2. b
3. b
4. c
5. d