Et Tubes Vs Lma

1 Intro

Since adequate breathing is always a first goal in supportive care or crisis rescue, it is essential in health care to establish a patent passage from the patient's mouth to their lungs in order for the patient to survive. This airway ensures unobstructed breathing for basic support or cardio-pulmonary resuscitation (CPR). There are two devices that are most commonly used and each device has specific indications and contraindication.

2 Research question

This study was done to answer the following question: Are licensed practitioner's beliefs about airways (oral ET-tube and LMA) consistent with the current printed information and do they report using the airways in a similar manner? To answer this question, we first needed to know what practices the current published studies have suggested will have better out-comes and less side affects. We also needed to find out; are practitioners aware of the evidence-based practices that are currently published and have they had any continuing education about airway management? Does the location where the practitioner performs airway management impact their practices? Are their decisions based on departmental policy or do they decide on their own which device to use? Does the medical specialty in which they practice or the number of years in their field impact their practices or predetermine their knowledge of the devices.

3 Literature Review

The first device is an oral endotracheal Tube (oral ET-tube). It consists of a thin-walled tube with a balloon near the distal end that seals the airway and a connection on the proximal end, which enables connection to resuscitation devices. The tube is inserted past the patient's epiglottis, through the patient's vocal chords using a laryngoscope. The laryngoscope is an "L" shaped tool with a light source at the end that is used to lift and open the patient's epiglottis so that the practitioner can visualize the ET tube passing through the vocal chords into the trachea. The balloon is inflated to seal the airway and prevent aspiration of gastric contents.

The second device is a Laryngeal-Mask Airway (LMA). It is a thin-walled tube connected to an inflatable elliptical shaped device that is inserted into the laryngeal airway. The epiglottis is usually free floating within the mask and does not obstruct the airway. When inflated, the mask fills and seals the upper airway and pushes the tongue forward. The thin walled tube exits the patient's airway and allows connection to resuscitation devices.

Current practice involves using the oral ET-tube as the standard for airway care. The manufacturer's manual for the LMA device also recommends that the oral ET-tube be the first choice for airway management due to the potential risk of regurgitation and aspiration when using an LMA. But a southeastern US study found that previous reports of aspiration while using the LMS device were exaggerated and in some regions, the LMA has replaced some of the other devices for airway management. (1999, Martin) The LMA is reserved for airways that are anatomically difficult to insert an oral ET-tube. (2005, LMA North America, Inc) A study in Philadelphia reinforced the use of the LMA device in difficult airways after being successful in establishing an airway in 68% of patients who had previously experienced a failed intubation. (1998, Parmet)

The LMA device is also contraindicated in patients that have a fixed pulmonary compliance or require high pressures to ventilate due to the LMA devices poor ability to seal the airway in this situation. Indicators that this may be happening could be an assessment that effective ventilation is not happening and/or signs that the patient is having difficulty oxygenating. In these cases it is important assess and correct the problem quickly. (2005, LMA North America, Inc)

The LMA airway is easier to use, requiring less training than the oral ET-tube. This may be important after two studies; one from Florida with 108 patients and one from Indianapolis with 208 subjects where in both, 25% of all intubated patients entering the emergency room had misplaced tubes. (2001, Katz)(2004, Jones) This may be important information because emergency patients without an airway may die. In fact, The Florida study reported that of the 108 patients studied nearly 10% of the patients died from complications stemming from a misplaced endotracheal tube into the esophagus. (2001, Katz)

4 Instrumentation

Subjects through out Chester County Hospital and Hahnemann University Hospital who were known to carry licenses that permitted them to insert artificial airways were mailed or handed surveys along with a pre-addressed, stamped envelope for return. Subjects were ensured that their participation and answers would be anonymous. The survey was developed to find out what practices are being done by anesthesiologists, CRNAs, respiratory therapists, physicians and paramedics in regards to airway choice for comparison with the current published information. Other questioning gathered information to help explain any variation of correlation between the practices of practitioners and the published information. These questions focused on their knowledge base about the airways, any dictators of airway choice, years experience, their licensed practice and clinical location of practice. Questions on the survey were as follows:

ADULT AIRWAY SURVEY

Please select only one "best" answer for each question

1. What is your current occupation?

a. Anesthesiologist

b. Certified Registered Nurse Anesthetist

c. Paramedic

d. Emergency Room physician

e. Respiratory Therapist

2. How many years have you been in this field?

a. 0 to 1 years

b. >1 to 5 years

c. >5 to 10 years

d. >10 to 20 years

e. >20 years

f.

3. When was the last time you received Continuing Education Units related to airways?

a. Within last 2 years

b. From >2 to 4 years