Advanced Airways: Endotracheal Intubation

Endotracheal Intubation

The following explains endotracheal intubation in detail.

Indications and Contraindications

Endotracheal intubation is indicated when it is necessary to control and protect the patient’s airway, when gas exchange is deranged and intubation will enable clinicians to correct hypoxia, acidosis or alkalosis through mechanical ventilation, when CPR is prolonged, or when the patient requires airway maintenance for long periods. 

When patients have conditions that can be corrected in a short time, endotracheal intubation is contraindicated. Note that intubation is not always necessary during CPR if adequate ventilations are provided with a bag-mask device. However, prolonged use of a bag-mask device may lead to insufflation of the stomach and subsequent regurgitation.²

Endotracheal Intubation in the Pre-hospital Setting

Most medical providers have heard the saying: “Just because you can, doesn’t mean you should.” Intubation is not without risks. Paramedics should keep that in mind before performing endotracheal intubation in the field. 

Paramedics should ask: 

1. Can the patient’s airway be managed effectively using less invasive means, such as a supraglottic device or bag-mask ventilation? 
2. How difficult is intubation likely to be in this patient? 
3. How long is transport to the hospital likely to take? 

Answering these questions will help paramedics in the field make the important determination of whether to intubate. 

Another point to consider include:

• Is the patient older? 
• Do they have any conditions that will make extubation difficult or unlikely? 
• Do they have a Do Not Resuscitate (DNR) directive stating that intubation is not wanted? 

Early consultation with the ED physician at the receiving hospital can help paramedics make difficult intubation decisions.

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Equipment Needed

It is important to know the equipment intimately and be ready for intubation at a moment’s notice, whether in the field or in the ED. Necessary equipment includes the following:

• Laryngoscope blades: curved (MacIntosh) and straight (Miller) blades of various sizes; ensure the light is functioning
• Laryngoscope handles
• Cuffed endotracheal tubes of different sizes (average size for an adult is 7.5)
• Stylet
• Oral and nasal airways of various sizes
• Yankauer suction tip catheter and suction tubing (set up before intubating)
• McGill forceps
• Syringe (to inflate the cuff on the ET tube)
• Bougie tube
• Carbon dioxide monitoring device
• Resuscitation bag (bag-mask device) attached to 100% oxygen (set up before intubating)
• Commercial tube securing device or tape
• Lubricating jelly (water soluble)

Equipment needed for intubation includes the laryngoscope, endotracheal tube, and a resuscitation bag.

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In the hospital setting, the equipment above is often kept in a kit or in a drawer of the crash cart for easy access. Equipment should be checked frequently for expiration dates and to ensure that no equipment is missing. All team members must know where to find all equipment when needed and should understand how to set it up and prepare for use. 

Specialized equipment, such as fiberoptic scopes and difficult intubation kits, may also be available in the hospital setting.

In cases of cardiac arrest, sedating the patient prior to intubation is not necessary. However, in most other instances, sedation is required prior to intubation.³ Sedation relaxes the muscles and facilitates easier intubation, and it makes the patient more comfortable. Generally, a paralytic agent is given, along with a muscle relaxant and pain medication. 

Prior to intubation, it is important to ensure that the patient’s oxygenation status is optimized. This does NOT mean that the patient should be hyperventilated.⁴

To optimize oxygenation, provide free flow oxygen from the resuscitation bag or provide high flow oxygen with a nasal cannula. A nonrebreather mask can also be used to hyperoxygenate the patient prior to intubation.

The intubation procedure is performed to control and protect the patient’s airways.

Once the patient has been successfully intubated by the most experienced team member, it is important to secure the airway to prevent dislodgement of the tube. That can be achieved using tape or a commercial device. 

Tube placement is confirmed by verifying that the patient has bilateral chest wall rise and breath sounds. An X-ray can confirm tube placement, but the X-ray must wait if the patient is in cardiac arrest. Most importantly, ensure there is a CO₂ detector attached to the ET tube and that it indicates tracheal placement of the endotracheal tube.

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Related Video – D.O.P.E. for Intubated Patients

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Waveform Capnography

Waveform capnography is a method of measuring end-tidal carbon dioxide levels — the amount of carbon dioxide that is produced after the exhalation phase of respiration. It can be measured if the patient has an advanced airway in place, such as an endotracheal tube.⁵

The presence of carbon dioxide after exhalation indicates that there is gas exchange within the alveoli; it also indicates adequate pulmonary blood flow. 

During cardiac arrest, end-tidal carbon dioxide levels reflect cardiac output that is generated by chest compressions. If the quality of CPR is maintained, then the end-tidal carbon dioxide levels will be acceptable.

The normal end-tidal carbon dioxide measurement is 35–45 mm Hg in adults. It is recommended that end-tidal carbon dioxide levels be maintained between 10–20 mm Hg during CPR.⁶ The range indicates that CPR quality is optimal and that the chances of return of spontaneous circulation are also good. 

Poor prognosis is expected if, after 20 minutes of CPR, waveform capnography records less than 10 mm Hg of carbon dioxide.

In summary, there are many uses for quantitative waveform capnography: 

1. It measures the quality of CPR.
2. It can prognosticate the outcome of the resuscitation effort.
3. It validates proper endotracheal tube placement.
4. It validates cardiac output and pulmonary perfusion.
5. It can guide mechanical ventilation settings.

Endotracheal intubation is used in patients requiring prolonged CPR to protect the airway and prevent aspiration. It is important that the medical team is practiced in inserting endotracheal tubes and has the necessary equipment at hand.