Screening

December 2, 2009

Regarding 10cc of saline or air in the cuff. My understanding is that you

only use as much air or saline as is necessary to anchor the tube at the

vocal chords. That is what the pilot balloon is for, as soon as the pilot

balloon is firm your tube is anchored. Securing happens when you use

whatever method to secure the tube at the mouth. Too much air or saline in

the cuff causes necrosis. 10cc of air is typically way to much. 4 to 6 cc is

usually sufficient. A c-collar is also recommended for limiting displacement

of the tube after you secure it.

December 4, 2009

Hhhhhhhmmmmm ! ! !

I have never used the Pilot balloon to assess cuff pressure and leakage

The more classic ways are :

With an ungloved hand and stethoscope

Deflate cuff till you detect leak

Then had back 1 cc (re-check)

or

Use a cuff gauged (Manometer with luer tip line)

And aim to have a cuff pressure inferior to 20-25 cmH2O (less on hypotensive

Pts)

Note that cuff pressure may vary during course of treatment (more so in peds)

Cuff pressure gauge are not absolutely necessary in first line care

But for anybody that is going to be intubated for greater than an hour

Cuff pressure checks are essential part of care

Assessing Endotracheal Tube Cuff Pressure

Standard methods of assessing endotracheal tube cuff pressure may not provide

adequate information

By Vivek Parwani, MD, In-Hei Hahn, MD, Krieger, MD, Zajac, MD, Dwight

Arakaki, MD, & J. Hoffman, MD

Establishing a secure airway via endotracheal intubation is a critical clinical

skill and lifesaving technique commonly used in the prehospital setting. The

procedure, however, can cause complications even long after the endotracheal

tube (ETT) is placed past the vocal cords and secured. Tracheal necrosis,1

rupture,2, 3 stenosis,4 laryngeal nerve palsy5,6 and tracheo-esophageal fistula7

are all potential risks when the pressure in ETT cuffs is excessively high.

It has long been believed, without any evidence-based data, that trained

clinicians are capable of determining proper ETT cuff pressures. More

specifically, it is presumed that clinicians can detect appropriate inflation

pressure and overinflated ETT cuffs by palpation of ETT pilot balloons. In this

study, we sought to evaluate newly trained paramedics' ability to inflate ETT

cuffs to a safe pressure, as well as to detect overinflated ETT cuffs by

palpating the pilot balloon. The phenomenon merits study because overinflation

of an ETT cuff may be prevented by using a manometer to directly measure

inflation pressure.1,8

Methods

Study Design

The study was a prospective, observational study of graduating paramedic

students' ability to properly inflate and palpate the pilot balloons of ETT

cuffs. This study was approved by the Institutional Review Board of St.

Luke's-Roosevelt Hospital Center. Informed consent was obtained from all

participants prior to the study.

Setting and Population

This cross-sectional study examined a cohort of 23 paramedic students graduating

an accredited one-year training program at an accredited U.S. college.

Study Protocol

We sought to determine the ability of the study population to inflate an ETT

cuff to a safe pressure using standard syringe technique. A secondary outcome

measure was the ability of the study participants to identify overinflated ETT

cuffs by palpation.

Safe pressure was defined as less than or equal to 25 cm H2O.9 Below this

pressure, capillary perfusion pressure is not typically impaired and there are

no expected risks of long-term compression damage to the human airway.

Standard syringe technique consisted of ETT cuff inflation using a syringe to

inject air into the cuff and, if participants chose to do so, assessment of cuff

pressure by palpation of the external pilot balloon. Specifically, a previously

tested simulation model10 with a 7.5 ETT and using a high-volume, low-pressure

cuff (Mallinkrodt, St. Louis, MO) placed into a 2.0 cm rigid cylinder. Study

participants were then allowed to choose either a 5 mL or 10 mL plastic syringe

with standard luer lock (Becton-Dickson, lin Lakes, NJ) to inflate the ETT

cuffs, while simultaneously manually palpating the pilot balloon as preferred.

After the participants completed inflation of the endotracheal tube cuff, the

cuff pressures were measured using a highly sensitive and accurate analog

manometer (Boerhinger Laboratories, Norristown, PA).

The second part of the study involved participants palpating the pilot balloons

of nine ETT cuffs previously inflated to pressures ranging from zero cm H2O to

120 cm H2O and reporting their assessment of pressure of each pilot balloon as

appropriate, too low or too high. The pressures, in cm H2O, were: 0, 4, 8, 16,

20, 22, 80, 100, 120.

Over an initial one-month pilot period, measurements of intracuff pressures with

participants not included in this study were performed. This was done to ensure

investigator skill in making measurements and to assess for flaws in protocol

design, implementation or conduct of the study.

Sample Size

Based on a previous study of this phenomenon in emergency medicine residents, a

sample size of five was expected to be adequate for statistical analysis, with a

1% significance level () and 80% power (1-). Rather than simply test five study

participants, we sampled the entire graduating class of 23.

Data Analysis

Our null study hypothesis was that the maximal ETT cuff pressure generated by

study participants would not exceed 25 cm H2O. A secondary hypothesis was that

study participants would be able to detect overinflated ETT cuffs by palpation.

A student's t-test and Chi-square test were utilized for hypothesis testing

where appropriate. Statistical analysis was performed using Intercooled Stata

8.2 statistical software (College Station, TX).

Results

The average ETT cuff pressure produced could not be precisely determined because

70% of participants (n=16) inflated to pressures greater than the upper limit of

manometer sensitivity (>120 cm H2O). Using the available censored data, however,

the average pressure generated was >98 cm H2O, range 50 - 120 cm H2O.

Using a one-tailed hypothesis test with of 0.01, the null hypothesis that the

mean pressure generated by study participants would not exceed 25 cm H2O was

rejected. The secondary hypothesis of participants' ability to detect

overinflated ETT cuffs by palpation was also rejected. Participants were only

26% sensitive detecting overinflated ETT cuffs. No participant correctly

identified all overinflated ETT cuffs.

Survey data revealed that 78% of participants (n=18) inflated ETT cuffs using

palpation of the pilot balloon to determine the quantity of air to inject into

the balloon when inflating an ETT cuff. The other participants preferred a

method of injecting a set volume of air into the cuff, 13% (n=3), or injecting

air until they perceived resistance, 9% (n=2).

Discussion

When the pressure in an ETT cuff exceeds the capillary perfusion pressure of the

tracheal mucosa, mucosal blood flow becomes obstructed. The precise pressure at

which capillary perfusion is impaired certainly will vary from patient to

patient, but reports suggest that 25 cm H2O is a " safe " pressure.9 The precise

pressure at which any individual will experience impaired or obstructed tracheal

mucosal blood flow will be dependent upon numerous factors, most importantly

their blood pressure. Severe overinflation of the ETT cuff may result in severe,

even fatal injury.3,11 Less severe, but significant, adverse effects are

tracheal pain or stridor.12, 13

This study demonstrates that recent paramedic graduates were unable to inflate

an ETT cuff to a safe pressure. These study participants were also unable to

differentiate overinflated ETT cuffs from appropriately inflated ETT cuffs by

palpation of the pilot balloon.

Although these graduating paramedic students grossly overestimated a safe

inflation pressure, comparison to a similar study examining the ability of

emergency medicine physicians and another study of practicing paramedics showed

that these students' abilities were similar to those of the more highly trained

or experienced groups.14,15 This implies that this skill is not acquired over

time with increased training or experience.

It has been suggested that using standardized instrumentation to measure cuff

pressure would help to decrease the possibility of injury resulting from

endotracheal intubation.1,8,16 Whether this is practical for paramedics to do in

the field is unknown. Use of such instruments might interfere with the top

priority of securing an airway or rapidly transporting the patient to a hospital

environment. Additionally, since there are little data available on short-term

complications, it is unclear what difference in outcome would result from

measuring inflation pressures in the field relative to measuring such pressures

in the hospital. This may be an area for future studies.

Prehospital professionals should consider the available information suggesting

that clinicians cannot detect overinflation of ETT cuffs by palpation of the

pilot balloon. Emergency department staff should consider taking it upon

themselves to measure cuff pressures after endotracheal intubations, whether

performed in the field or in the ED, as it is a certain method of detecting

overinflated ETT cuffs. Many patients who remain intubated eventually have their

ETT cuff pressure checked by respiratory therapists or intensive care unit

staff. However, since overinflation of ETT cuffs is recognized as potentially

injurious, prehospital personnel and emergency medicine clinicians should

consider screening for overinflation of ETT cuffs.

The inability of clinicians to determine endotracheal tube cuff pressure by the

traditional standard method of palpation of the pilot balloon has been addressed

by other investigators. Anesthesiologists,17 as well as critical care unit

staff,1,18 have demonstrated a prevalent inability to accurately determine

intracuff pressure of the ETT cuff by palpation of the pilot balloon.

The risk of injury resulting from an overinflated ETT cuff warrants evaluation

of currently employed endotracheal intubation practices. The practice of

inflating ETT cuffs without precisely measuring such pressure, in particular,

should be closely scrutinized.

Limitations

As conducted, this study has several potential limitations. The first of these

is that the model does not precisely resemble the human airway in shape or

compliance. Participants might have performed better and responded differently

in live scenarios where real patients were involved. However, ethical

considerations preclude being able to conduct such a study on human patients.

Secondly, physiologic variations among human tracheal blood flow might provide

for a variation of safe cuff insufflation pressures from person to person, thus

limiting the relevance of a study examining a single uniform simulated

intubation environment.

A sample size of 23 is considered small for the purposes of statistical

analysis. Although the results of this study did not raise any concern that the

study lacked power, it would be optimal to have had a larger sample size.

Lastly, it is hard to evaluate the uniformity of the group, as students often

have not all achieved the same skills set or experience. There is the potential

to have variation in outcomes based on individual students' training and

experience.

References

1. Fernandez R, Blanch L, Mancebo J, et al. Endotracheal tube cuff pressure

assessment: Pitfalls of finger estimation and need for objective measurement.

Crit Care Med 18:1423 - 1426, 1990.

2. Fan C, Chow P, Tsai K, et al. Tracheal rupture complicating emergent

endotracheal intubation. Am J Emerg Med 22:289 - 293, 2004.

3. R, ph A. Acute tracheal rupture related to endotracheal

intubation: Case report. J Emerg Med 18:35 - 39, 2000.

4. Terashima H, Sakuri T, Takahashi S, et al. Post-intubation tracheal stenosis:

Problems associated with choice of management [abstract]. Jpn J Thorac

Cardiovasc Surg 55:837 - 842, 2002.

5. Lu YH, Hsieh MW, Tong YH. Unilateral vocal cord paralysis following

endotracheal intubationâ€”a case report [abstract]. Acta Anaesthesiol Sin 37:221

- 224, 1999.

6. Otani S, Fujii H, Kurasako N, et al. Recurrent nerve palsy after endotracheal

intubation [abstract]. Masui 47:350 - 355, 1998.

7. Pelc P, Prigogine T, Bisschop P, Jortay A. Tracheoesophageal fistula: Case

report and review of literature [abstract]. Acta Otorhinolaryngol Belg 55:273 -

278, 2001.

8. S, Secrest J, Norwood B, Zachary R. A comparison of endotracheal tube

cuff pressures using estimation techniques and direct intracuff measurement.

AANA J 71:443 - 447, 2003.

9. Guyton DC. Endotracheal and tracheotomy tube cuff design: Influence on

tracheal damage. Crit Care Update 1:1 - 10, 1990.

10. Hoffman RJ, Parwani V, Hahn IH. Emergency medicine physicians cannot inflate

or estimate endotracheal tube cuff pressure using standard techniques

[abstract]. Ann Emerg Med 44:s118 - s119, 2004.

11. Guyton DC, Barlow MR, Besselievre TR. Influence of airway pressure on

minimum occlusive endotracheal tube cuff pressure. Crit Care Med 25:91 - 94,

1997.

12. Mandoe H, Nikolajsen L, Lintrup U, et al. Sore throat after endotracheal

intubation [abstract]. Anesth Analg 74:897 - 900, 1992.

13. Efferen LS, Elsakr A. Post-extubation stridor: Risk factors and outcome. J

Assoc Acad Minor Phys 9:65 - 68, 1998.

14. Parwani V, Hahn I, Hsu B, Hoffman R. Experienced emergency physicians cannot

safely or accurately inflate endotracheal tube cuffs or estimate endotracheal

tube cuff pressure using standard technique [abstract]. Acad Emerg Med 11:490,

2004. 15. Parwani V, Hahn I, Hoffman RJ. Experienced paramedics cannot inflate

or estimate endotracheal tube cuff pressure using standard techniques

[abstract]. Ann Emerg Med s44s64, 20 - 04.

16. Braz J, Navarro L, Takata I, Nascimento P. Endotracheal tube cuff pressure:

Need for precise measurement. Sao o Med J 117:243 - 247, 1999.

17. Foroughi V, Sripada R. Sensitivity of tactile examination of endotracheal

tube intra-cuff pressure. [abstract] Anesthesiology 87:965A, 1997.

18. Ganner C. The accurate measurement of endotracheal tube cuff pressures. Br J

Nurs 10:1127 - 1134, 2001.

Vivek Parwani, MD, is an assistant clinical professor and EMS physician at the

Yale University School of Medicine, Division of EMS, Section of Emergency

Medicine.

In-Hei Hahn, MD, is an emergency medicine physician with fellowship training in

medical toxicology. She is an assistant clinical professor and assistant

director of research in the Dept of Emergency Medicine at the St.

Luke's-Roosevelt Hospital Center, New York, NY.

Krieger, MD, Zajac, MD, & Dwight Arakaki, MD, are resident physicians

at Beth Israel Medical Center, Department of Emergency Medicine, New York, NY.

J. Hoffman, MD, is a pediatric emergency physician and research director

in the Department of Emergency Medicine at the Beth Israel Medical Center, New

York, NY.

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC535565/

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________________________________

From: garth gilmer <sffdparamedic@...>

Sent: Wed, December 2, 2009 8:10:21 PM

Subject: Re: Screening

Regarding 10cc of saline or air in the cuff. My understanding is that you

only use as much air or saline as is necessary to anchor the tube at the

vocal chords. That is what the pilot balloon is for, as soon as the pilot

balloon is firm your tube is anchored. Securing happens when you use

whatever method to secure the tube at the mouth. Too much air or saline in

the cuff causes necrosis. 10cc of air is typically way to much. 4 to 6 cc is

usually sufficient. A c-collar is also recommended for limiting displacement

of the tube after you secure it.

December 4, 2009

I agree completely. Instead of just blasting 10cc of air into a cuff to 'check'

it like is often taught (which, in my opinion, just stretches out the material

and weakens it,) more attention should be paid to the amount of air one uses to

completely inflate it, then having only that much air in the syringe (so in the

heat of the moment, you can't overdo it.) The pilot balloon is a perfectly

appropriate though rough guide to ensure your cuff isn't overinflated. Using a

'manometer' or other similar technique just isn't practical in any environment

that I've worked in.

Austin

On Dec 2, 2009, at 7:10 PM, garth gilmer wrote:

> Regarding 10cc of saline or air in the cuff. My understanding is that you

> only use as much air or saline as is necessary to anchor the tube at the

> vocal chords. That is what the pilot balloon is for, as soon as the pilot

> balloon is firm your tube is anchored. Securing happens when you use

> whatever method to secure the tube at the mouth. Too much air or saline in

> the cuff causes necrosis. 10cc of air is typically way to much. 4 to 6 cc is

> usually sufficient. A c-collar is also recommended for limiting displacement

> of the tube after you secure it.

>

December 5, 2009

Regarding pilot balloon usage to detect properly inflated cuffs of ETT.

Thanks for the data. My paramedic brain does not do well deciphering

clinical data. Care to break it down for me?

I was shown a demonstration by a twenty year medic working for San Francisco

Fire Department who assists in teaching airway classes. If you take your

pinky, which is approx the size of your glottic opening and then place your

fist of the other hand over your pinky, then remove it keeping the opening

in your fist the size that your pinky left, you can simulate the soft tissue

of the glottic opening by inserting an ETT and inflate to the 10cc and watch

the pressure placed on the soft tissue of your hand. Then deflate and

re-insert air from the syringe until the pilot balloon is just firm, tug on

the ETT to see that it is anchored. Try it and let me know what you think?

Garth

December 6, 2009

Dear Garth:

Mind if I play ?

The technique described below is not acceptable in my " hood " typically a 20 y/o

Fire Monkey Medic approach ;>) The ETT cuff should NEVER be considered a means

to point of anchor, sheesh !

What B may be saying and most likely one of the best field techniques,

this is called by Respiratory Therapists the MOV (Minimal Occluding Volume) as

your having difficulty wrapping your head around this, I will expound a tad.

After intubating and visualizing cords, and not putting the ETT into the cats

anus !

1- Put a volume (AIR) in the cuff until a small amount of resistance is

encountered .... FIRM NO! <insert sounds of hand slap>

(key word SMALL and allow time for equilibration as its a slower do fill not

FAST as in IVPush as in adenosine)

2- Then attach the Manual Resuscitator (BVM) gently there in most cases is not a

High Pressure blow off Valve on the BVMs (typically) although not a bad idea for

some.

3- Then upon squeezing the bag on " Inspiration " and USING a stethoscope.

4- A very small leak/ squeak should be heard/ auscultated.

Best advice is keep the PIP (Peak Inspiratory Pressures) > 40 cmh20 short term,

that's ~ 29 Torr/mmhg or.039 bar. (if I did the math correctly) and that little

squeak assists in removing oral secretions between cords and cuff as well,

decreasing possibilities of micro aspiration and VAP or just blow a Pnemo

right at the get go. This M.O.V. assures that at least pressures are ~ 40 cmh2O

and a Tracheal Stent is not required as a result of a necrotic trachea and

complication's down the road that said that's if the patient actually survives.

Note well that venous return in the Mainstem Bronchus is a serious

consideration, THE BEST practice is a cheap Cuff Pressure Gauge oh yes really,

really, guaranteeing cuff pressures = to or > than 25 cmH20 as clearly

states.

One can implement a poor mans approach (killing 2 birds with one stone so to

speak) use an in-line manometer as for the most part in short periods of

ventilation a " priority consideration " is overinflation and unrecognized DHI

(Dynamic Hyper Inflation) which can inadvertently negatively affect Left Atrial

Filling Pressures resulting in PEA from a " relative " hypovolemia and/or in the

case of a patient seriously compromise B/P in any hypoperfusion states for any

reason. The new ILCOR guidelines in CPR 30:2 single person does address this

issue (in part) as many out there believe that once a BVM is attached its

acceptable to use the inflate a <insert sarcasm> " SCUBA TANK Technique " the

Guideline's in tidal volume should be 5 to 7 mls per KG IDEAL BODY WT! Most BVMs

have capability of squashing in 1500 mls. sorry got on a roll there ;>()

Garth:

1- This study shows that most Paramedics typically OVERINFLATE the cuff and only

a very small % have enough experiance to estimate the pressure from the " squeeze

the pilot balloon " thingy.

2- The use of a gauge is recommended (see post) for recommended

pressures.

3- That the King LT is a piece of Junk as is LMA (as are most supraglitic

devices) sorry Larry T. (see my RANT about 2 years ago) UNLESS very, very short

tem (or used in a cadaver) or a patient that is know NOT to have a belly full of

" bangers and mash " on board. Just IMHO unless one is an idiot (i.e. rescue

devices only) with the proviso: Working in a pressurized cigar tube, what I

prefer is the Bougie Gum Rubber (besides its just fun to say !) as an Introducer

and my back up to do a retrograde intubation, as it saves a blood bath.

In Closing the use of N/S in ETT is now ill advised, if one does the math (IDEAL

GAS LAWS) even at a cabin pressure of 10,000 ft ASL (and intubated at 1 ft ASL)

the pressure changes are negligible, that said about 20 years ago this was

acceptable procedure but the cuffs and pilot balloon were never designed for

fluid, if one still wants to use fluid filled cuff and disregard the legal

issues as well surrounding this very old idea. PLEASE do me a personal favour

and put a piece of tape and use a pen and write " H20 FILLED " its a bitch to

quickly extubate, that said unless one is in a pressurized F/W Aircraft and is

" expecting " a sudden decompression blowing out a window's at 40 G this concept

is just a waste of effort.

cheers

Wilf

Re: Screening