ETT Cuff Inflation

The majority of providers use an injection of air with a 10 cc syringe followed by manual palpation of the external balloon. This technique may fail to provide safe parameters for the patient. Many over-inflate, compromising tracheal perfusion. Many under-inflate, placing the patient at risk of micro-aspirations and pneumonia. Very few are in the acceptable range of 20-30 cm H2O pressure.

Research: In a study to compare three different means of inflating the pilot balloon (the injection and palpation method, the minimum occlusive technique and the set volume of air), Evans found NONE were within the appropriate range. Braz found high cuff pressure (>40 cm H₂O) in 90.6 % of patients, and Wujtewicz found a tendency toward over-inflation of endotracheal tube cuffs with the problem more common in highly experienced anaesthesiologists. He also found over-inflation was more prevalent in 2009 than in 2002.

Other studies to support the need of a cuff manometer include:

·       “The mean intracuff pressure measured in the study group was 118.9 (SD= 54.3).” Koay.                                               

·      “ This study revealed that the majority of cuff pressures exceeded safe pressure and required correction. Frequent measurement and adjustment of cuff pressure has been recommended, but this method requires a specific manometer.” Galinski.

There are no studies to support cuff inflation by any means other than a cuff manometer. Even as far back as 1979, Watson stated the need for a pressure gauge to take the “blindness” out of the art of anesthesia.

Injury to the patient can occur from an under- or over-inflated pilot balloon. A pressure less then 20 cm H₂O places the patient at risk for micro-aspirations and ventilator-dependent pneumonia. Pressures greater than 30 can cause extreme injury of the trachea as documented by Nordin. Excerpts of his findings:

 “When the tube was placed in the trachea without inflation of the cuff it was quite clear that this was sufficient to cause minor superficial damage to the epithelial lamina. This damage only occurred over regions where a cartilage was situated. When the cuff was inflated, it resulted in an increase of the mucosal damage to the extent of the injury being directly related to the pressure in the cuff. A gradual increase in C-T (cuff tracheal) pressure led to progressive extension of the mucosal damage.”

 “A C-T pressure of 20 mmHg for 1 to 2 h of intubation damaged the mucosa on top of the cartilages to such an extent that it was partly denuded almost down to the basement membrane.

 “A C-T pressure of 50 mmHg for 2 h of intubation destroyed most of the epithelial cells on top of the cartilages. The basement membrane was partly denuded but seemed intact.

 “At a C-T pressure of 100 mmHg for 1 h of intubation the whole part of the mucosa at cuff level was now damaged to some extent. Large areas of the basement membrane were denuded and in some areas it was completely absent, leaving the mucosal stroma visible. After 4 h of intubation the mucosa covering the cartilages were sometimes destroyed down to the cartilage itself, and bacteria were found, for the first time, to be invading the damaged mucosa.”

There is no research to support cuff pressure greater than 30 cm. If you believe your department can safely inflate the ETT cuff without a manometer, I urge you to test your theory with a pressure gauge. An example of pressures obtained without the use of a cuff manometer is displayed in the following graph. Note that the majority fall outside acceptable limits.

A discussion of time and tracheal injury must also be initiated. The “old” mindset is that damage can only occur with long-term intubations. This perspective must be changed. According to three separate authors, Dedo, Somri and Raynham, ischemic injury of the tracheal mucosa begins within 15 minutes with cuff pressures  > 30 cm. Somri also states that tracheal mucosal blood flow is totally obstructed at 45 cm. According to Dedo, over-inflation for even a brief operation can lead to tracheal stenosis within 1 to 3 months. In conjunction with tracheal ischemia from high cuff pressures, decreased blood flow from hypovolemia, anemia, shock and metabolic acidosis will cause even greater compromise.

Just as the nerves of the arms and legs are protected during surgery, we need to protect the nerves and blood supply of the trachea with the same care. It is essential to use smaller size ETTs and to check cuff pressure with each and every intubation. We need to bring new standards into the OR. The lives and well-being of our patients depend on it.

To conclude, we can no longer ignore these critical problems or the volume of supporting research before us. Our patients place their lives and safety in our hands. It is both an honor and a great responsibility, and we must take the initiative to adopt practices that validate this trust.

It is vital to adopt these new standards:

            New Standard #1: Take cuff pressure measurements with every intubation.

            New Standard #2: Standardize most female ETTs to size 6.0 and size 7.0/7.5 for men.

I do recognize that calling for new standards in this way is highly unconventional. However, no change has taken place in these routine ETT practices, even with the volume of research and papers that have been published on the topic

The following bibliography consists of studies that support my position. I urge you to read these articles carefully and then join me in the declaration of the need for these new standards.

To keep the focus on the problem and not the author, I am omitting my name but can be reached by email at LoveYourTrachea@gmail.com

This paper has been submitted for copyright status.

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