Patient 1: You are preparing to intubate a 35-year-old trauma patient with a closed head injury and pulmonary contusion. The saturation is 90% on a non-rebreather. After paralysis and induction, the saturation immediately starts to plummet. The respiratory therapist initiates one-person bag-valve-mask ventilation (BVMV) while you hurriedly get in position to intubate. The saturations continue to drop so you quickly attempt intubation. The intubation is difficult, and the patient goes into bradyasystolic arrest, and does not recover.
Patient 2: You are using propofol to sedate a morbidly obese 26-year-old who needs a large abscess drained. The end-tidal CO2 monitor alarms for apnea, and the patient rapidly becomes hypoxemic despite stimulation and supplemental oxygen. You call for help and quickly begin BVMV, but the patient is extremely difficult to ventilate. Your partner arrives, and you successfully intubate the patient with a video laryngoscope. The patient is difficult to wean from the vent, and spends two weeks in the hospital before finally being discharged.
Patient 3: A visitor codes, and is brought to the ED by the rapid response team after a successful conversion of v-fib to sinus tachycardia. They were unable to intubate the patient, and are performing BVMV; the patient remains unresponsive. There is some question of the patient's code status so you elect to continue BVMV. Within a few minutes, you determine that the patient is, in fact, full-code, and you elect to intubate. At this point, you note the patient has developed substantial gastric insufflation. When you attempt to intubate, the patient regurgitates, completely obscuring your view.
What could have been done differently in these cases? Perhaps patients 1 and 3 would have been better served with an extraglottic airway that allows gastric decompression while patient 2 ideally should not have been deeply sedated in the ED. But this is hindsight. First and foremost, we need to discuss better BVMV technique, one of our most fundamental airway skills yet also one of the most difficult. Even worse, BVMV often falls to one of the least experienced team members to perform.
Our Airway911 program currently uses the “Rule of Threes” to remember the components of optimal BVMV. Not every patient requires optimal BVMV; one blindfolded rescuer may successfully bag some patients with one arm tied behind his back! Other patients cannot even be ventilated with optimal technique, but this is unusual. Optimal BVMV will usually keep you and your patients out of trouble.
Three People: Ideally one person will be dedicated to maintaining a mask seal while another person squeezes the bag; the third person provides cricoid pressure. Unless you have massive hands, this is the single most important step to optimal BVMV. If fewer hands are available, the patient may be placed on the vent.
Three Fingers: Cricoid pressure has become appropriately controversial for intubation as highlighted in the latest American Heart Association guidelines, but I believe it still has an important role in BVMV; I hope the authors of the ACLS and BLS texts do not throw the baby out with the bath water.
I recently had to bag a trauma patient for 30 minutes in the field. We did optimal BVMV, including cricoid pressure, and the patient did not have any detectable gastric insufflation after 30 minutes. We then released the cricoid pressure, and performed external laryngeal manipulation during intubation in the ED.
Three Airways: I was taught to use an oral pharyngeal or nasopharyngeal airway, depending on the presence of a gag reflex. Nobody ever told me as a young medic or doctor that I could use more than one device at the same time. For any patient with proven or predicted difficult BVMV, it is now my routine to use at least two airways and sometimes three. If they have a gag reflex, I might use bilateral nasal airways, and if they don't, I will use one oral airway along with one or two nasal!
Three Inches: It turns out the optimal position for intubation, ear and sternal notch at the same horizontal level, is also the optimal position for BVMV (assuming no cervical spine precautions). It makes sense that the position that maximally aligns the airway axes for intubation would maximally open the airway for BVMV.
Three Seconds: This is the reminder to use slow ventilation and allow plenty of time for exhalation. Some studies that observe providers during CPR have noted ventilation rates above 60 per minute. That can cause a host of problems, and must be avoided. The best way to ensure slow ventilations is to put the patient on a vent or use a commercial device that times ventilations.
Three PSI: While we don't literally mean 3 PSI, this is a reminder to use the lowest possible pressures to raise the chest. Less pressure means less turbulent flow and less air entry into the stomach.
Three PEEP: When we have trouble oxygenating a patient who is on a mechanical ventilator everyone thinks of adding PEEP, yet this is often overlooked with BVMV. You can purchase inexpensive PEEP valves that attach to the exhalation port of the BVM or buy a BVM that has an integral PEEP valve. While these provide only crude measures of PEEP, they absolutely work. We now have these at every bedside in our trauma/resuscitation area and in many of our ambulances. The other option is to just go ahead and connect the mask to a vent.
All of these components work together. I have had several opportunities to observe the incremental benefit of each component as more help arrived and we could initiate three-person bagging, get the patient better positioned, find the airway adjuncts, and employ PEEP. It really does work!
As I have mentioned several times, the most sophisticated way to perform mask ventilation is to use the ventilator. The vent frees up hands, and ensures the appropriate rate, pressures, and PEEP. Most ED providers are not familiar with this technique though it is present in the literature (J Emerg Med 2006;30:63; Resuscitation 2007;73:123), and has been advocated for some time by Dr. Scott Weingart of the EMCrit blog.
Whenever ventilation and oxygenation prove difficult despite optimal BVMV, I would suggest discontinuing other efforts and placing an extraglottic airway. (See my Special Report from June.)
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Dr. Braudeis an associate professor of emergency medicine and anesthesiology and the director of the EMS Fellowship, the Physician Field Response Program, and Airway911 at the University of New Mexico School of Medicine, and the author of Rapid Sequence Intubation and Rapid Sequence Airway, 2nd Edition: An Airway Guide, available at http://airway911.com. He is also the associate medical director of the Difficult Airway Course-EMS.
Read all of Dr. Braude's past columns in the EM-News.comarchive.