Myth Busting

Arguments against the arguments in support of “routine anesthesia practice” (size 7 ETT for women and the injection and palpation technique of cuff inflation) and why they are wrong.

Subglottic stenosis (SGS) only occurs with prolonged intubation.

All research shows damage begins within 15 minutes of high cuff pressure.

It is safe to use the injection and palpation technique to inflate the cuff.

The palpation technique results in the majority of cuff pressures being too high and the risks of SGS, post-operative sore throats, post-operative hoarseness and recurrent laryngeal nerve damage. The minimal occlusive technique can result in the majority of cuff pressures being too low and the risk of aspiration and pneumonia. The potential life-long complications are too damaging to the patient if cuff pressure is not regulated by a manometer to safe limits.

That intubation was too long ago to be the cause of SGS.

Patient evidence clearly shows it takes years from an intubation and the diagnosis of SGS. Most patients are misdiagnosed for years and treated for the wrong problem (GERD, asthma, panic attacks) for years prior to the correct diagnosis. One paper clearly shows the link between an intubation and the diagnosis of SGS 20 years later.

The medical community accepts that COPD can be diagnosed 20 years after a patient stops smoking but will not accept that SGS can take years to narrow the trachea to the critical diameter of 4-5 mm.

The medical community will accept that a patient with a sexually transmitted disease will develop urethral strictures years afterwards but will not accept SGS can develop over the same time periods.

The medical community has no problem accepting that arteries narrow over time due to poor diets lifestyles but will not accept the same with tracheal stenosis developing slowly after ischemic damage. No-one knows exactly how long tracheal stenosis takes to develop.

If there was a problem with intubation and SGS, there would be lawsuits.

Lawyers will frequently turn down patient cases because of the length of time from intubation to diagnosis of SGS. Doctors often label SGS as ‘idiopathic’ without looking at old medical records for a history of intubation and patients are rarely aware if they have been intubated for surgery.

SGS occurs more frequently in females so it must be hormones.

Females have much smaller tracheas so they are more vulnerable to over-inflated cuffs and the use of large size endotracheal tubes. A size 7.0 ETT is the inner diameter, and the outer diameter is 9.6 mm; add over-inflation of the cuff, and the ETT diameter is now 25mm. A female tracheal diameter can be as small as 6.8 mm.

One study shows ten women with cuff pressures over 100 cm H2O pressure as compared to only one man, the frequently quoted ratio of females compared to males with SGS.

The ETT cuffs are low pressure.

The cuffs are low pressure until they are over-inflated and then they are immediately converted to high pressure cuffs.

Routine use of size 7 for women and size 8 for men is based on extensive research.

There is no supporting evidence in the routine practice of using size 7 for women. Research supports smaller-sized ETTs (<7) for women and cuff pressure monitoring for every intubation.

I need to use big endotracheal tubes because of Work of Breathing.

This theory was dispelled in the 1980s.

I don’t have to worry about over-inflating LMA cuffs.

Over-inflated LMA cuffs can cause ischemic and pressure damage to the blood supply and nerves of the trachea. The LMA directions for cuff inflation clearly states “Do not over-inflate cuff”. In every surgery, every part of the body is protected against any kind of pressure or nerve damage because of the known damage that can occur, why is the trachea not protected in the same way?

More research is needed.

There are volumes of research to support the needed changes. The published research in support of checking cuff pressure with a manometer and downsizing ETTs is ignored. We do not need more research; we need mandated measures to protect patients from harm.

Since I don’t measure the cuff pressure, I can’t be liable for injuries.

The Hippocratic Oath: First of all, do no harm.

A cuff manometer is too expensive.

A cuff manometer costs around $200.00 from VBM medical. How much is a trachea and a patients life worth?

There are no standards from the American Society of Anesthesiologist or the American Association of Nurse Anesthetist mandating cuff pressure measurement and the use of endotracheal tube sizing based on the patients tracheal diameter.

Sadly, TRUE. New safety standards must be put in place to protect our patients from harm.