In EMS education, we learn that airway management is the most critical aspect of patient care. It’s the first thing we’re taught to assess in a patient, and airway skills are drilled into providers throughout their training and careers, so it’s easy to become complacent assuming we know all there is to know about this very basic but very important skill. In their presentation, “Airway Tips, Errors to Avoid” at EMS World Expo Virtual on Wednesday, Sept. 16, Drs. Andrew Latimer and Gustavo Flores discuss the danger of this complacency and how to master airway management skills. “Just because using a BVM is a basic skill does not mean our skill level should be basic,” said Flores.
High Performance Airway Management for BLS
Latimer, associate medical director at Airlift Northwest and prehospital physician at University of Washington, shared his ideas for the gold standard of airway management. One is optimal patient positioning. Supine or semi-reclined positions help ALS providers better visualize the vocal cords pre-intubation, but it makes airway skills easier on the BLS provider, too. The head-tilt, chin-lift is also helpful coupled with elevating the head. Use rolled towels or pillows to create a triangular ramp under the patient’s head and neck, making sure to align the ear to the sternal notch. This pre-oxygenation position makes the mechanics of an intubation attempt easier. Another option is the reverse Trendelenburg position to elevate the patient’s body at a 30-degree angle.
Proper mask seals are also vital to successful oxygenation. The classic “C-E” grip with the thumb and forefinger cupping the mask of a BVM and the other three fingers lifting the patient’s jaw is difficult to do well, especially if you don’t practice this skill often. Latimer’s ideal mask seal involves two providers. One uses the meaty part of the bases of their thumbs to apply the mask to the patient’s face and uses the other fingers to perform a jaw thrust (he compares it to the grip of the creature in Alien—see photo). Not only is it easier to create a tighter seal and adjust for any leaks with both hands, but it’s less fatiguing. This person controls the mask and the airway while the other provider ventilates the patient with the bag. With good coaching, you can even enlist bystanders if there aren’t enough crew members to use this method while performing other interventions.
For patients experiencing a severe respiratory process with potential need for intubation, whether airway collapse is pending or present, Latimer recommends flush rate preoxygenation. This means providing as much oxygen as you can. If you’re preoxygenating before an ALS intervention, set both a nasal cannula and non-rebreather mask to flush rates. While we typically set a nasal cannula between 2-6 lpm, some cylinders can reach 25 liters (use this for patients breathing spontaneously). Then you’ll want to place an NRB mask on top of that at 15 lpm. Another option is to place a nasal cannula under a BVM at 12-15 lpm.
“This is not a long-term solution, but for the period of critical illness prior to airway management,” says Latimer. “In the minutes before and during an advanced airway attempt, BLS is a critical part of airway management, even if we’re not performing an intervention or critical maneuver.”
The goal during this intervention in the critically ill during the peri-intubation phase is denitrogenation, which means getting as much nitrogen out of the blood and dead space in the lungs as possible by providing multiple sources of high-flow oxygen to prevent hypoxia. His recommendations: either a BVM with an NC both at 25 LPM, or an NRB with an NC at 25 LPM. Aim to get 100% saturation for 2-3 minutes (this can also be applied to trauma patients). When it comes to airway adjuncts, Latimer prefers to use an OPA as well as 2 NPAs. Extraglottic devices, like laryngeal masks, are also great for BLS providers as these can be blindly placed in the airway.
Though EMTs don’t study capnography in school, there is a simple way they can read the waveforms on a monitor when working with ALS providers to ensure they have a good mask seal. While there isn’t an easy answer for what every patient’s EtCO2 reading should be, says Latimer, waveform shapes are valuable in providing insight into how much air is leaking from a BVM (ask the medic what the target EtCO2 is when bagging an intubated patient). Simply put, low waves indicate poor bagging while flat waveforms with high plateaus indicate good bagging (pictured). The BLS provider can actually watch the breath-to-breath waveforms while bagging the patient.
Latimer emphasizes using capnography readings of the CO2 to confirm a good seal and stresses not to slow ventilation rates to artificially raise the CO2 to a normal value. Combined with good positioning and proper mask seals, preoxygenation, and airway adjuncts, the BLS provider can ensure high-quality airway management.
The Pitfalls of BVM Utilization
“Using a BVM is a skill that is not respected enough,” said Flores, MD, NRP, FP-C, director of ECCtrainings, LLC and associate editor of EMS World Americas. “Its difficulty is underestimated, and our ability is overestimated. I hope to instill confidence in your ability but also instill wisdom on some critical aspects that have either been forgotten or not considered when performing this critical skill.”
When artificially (positively) ventilating a patient, you’re inverting the body’s natural (negative) mechanism, which changes the physiological process of inhalation and exhalation. This is an important component of the respiratory process to understand. A BVM is capable of delivering approximately 1,475 ml of volume, far more than needed. On average, adults only need 450-600 ml of tidal volume per breath. Forced air is going to follow the path of least resistance, likely ending up in the esophagus and trachea. We know this can cause gastric distention, but a worse adverse side effect of distention is regurgitation, causing airway obstruction and aspiration without rapid intervention. “You may celebrate the fact that you got ROSC only to learn the patient died of sepsis a couple days later,” said Flores, as aspiration pneumonia has a high mortality rate.
If not used properly, a BVM can cause more harm than good. Flores discussed the three major pitfalls of BVM use.
Pitfall 1: Excessive Tidal Volume
To avoid overventilation, only compress half the volume of a BVM. Maintain the squeeze for one second before releasing. Flores’ pro tip? Consider an alternate hold. He sometimes holds the bag from the side or just the corner to limit the amount of volume he’s capable of compressing.
Pitfall 2: Excessive Pressure
A number of pressure gauges on the market help limit the pressure you deliver with a BVM. For example, a manometer is a handy device that can be attached to a BVM to measure the amount of pressure you’re applying with each ventilation. Reading it is as simple as maintaining the moving hand within the green zone. If you need to take it down a notch, Flores suggested using one or two fingers to compress the bag—you’ll realize how little pressure is actually needed to deliver adequate ventilations and tidal volume.
Also important is measuring the frequency of your ventilations. Flores said to either assist the patient’s ventilations at their own rate, unless the patient is in cardiac arrest, in which case you’d deliver the standard one breath every six seconds. The best way to ensure you’re bagging properly is to measure it, and not by your own counting. Use the timer on your cell phone to ensure an effective delivery—it’s easy to miscount in the middle of all the action. Whether trained or untrained, crews tend to deliver a very high frequency of ventilations, said Flores. Errors are inevitable when compounding this high frequency with extra pressure and volume.
Pitfall 3: Not Focusing on Your Task
If you are assigned to bag the patient, don’t try multitasking, which can slash your efficacy by 50%. Focus on high performance—when you do this one job really well, you help the rest of your crew by eliminating the need for further interventions. It’s one less problem the team leader needs to worry about—no advanced airway interventions should be needed because you couldn’t effectively ventilate a patient with a basic skill, said Flores. However, though a basic skill, it’s not a simple one, he says, because you’re juggling volume, pressure and frequency simultaneously. “Just because it’s simple, doesn’t mean it’s easy!”
Valerie Amato, NREMT is associate editor of EMS World. Reach her at. firstname.lastname@example.org or follow her on twitter @ValerieAmato2.