In my locale, a patent BLS airway (good chest rise) is all thats required during the code. If time allows, or its a dual medic ambulance, than the ET intubation is still the golden standard.
I assume we're talking about BLS airway, as in OPA / NPA + BVM, versus a King, LMA or Combitube, right?
[QUOTEI understand the idea of reducing intrathoracic pressure and how this benefits Frank Starling's Law, but if you're talking about giving 2 ventilations with a BLS airway, wouldn't the first compression or so negate the air into the lungs and return the thoracic cavity to the pressure maintained during compressions.
If we're just talking about an OPA / NPA scenario, then it's probably hard to cause a large increase in intrathoracic pressure doing 30:2. Providing you're actually doing 30:2.
A lot of the intrathoracic pressure issues probably relate more to situations where an advanced airway is in place, and asynchronous compression are ongoing, when a lot of people tend to hyperventilate.
I think one of the basic points of working a code is ensuring that you have a patent airway.
The argument here is a balance of risks. For most people an OPA / NPA, or head-tilt chin-lift is sufficient to maintain an open (patent) airway. But it doesn't protect against aspiration, as there's no cuff isolating the trachea. It also doesn't allow the use of higher airway pressures without risking gastric insulffation.
On the other hand, ETI usually requires a pause in compressions, both to pass the tube, and to confirm placement safely. But it allows for higher airway pressures if there's a lot of airway resistance, and protects better against aspiration.
The current guidelines recognise the King or LMA as a intermediate solution. It's easy enough (supposedly; I've never placed either during compressions) to place during compressions, provides some protection against aspiration, and allows higher airway pressures (thought the cuffs tend to leak a little more). The big advantage is that they don't require interruption of compressions, and in many places can be inserted by a non-ALS provider, so that whoever is actually running the code can do something else, like run the code. It's more challenging to do that when you're elbow deep in the airway.
If you simply place a NRB mask on at 15LPM how can you verify that any of that O2 is even getting to the lungs?
I think this is a current subject of research. Compression-only CPR has been recommended for lay people, and there's continuing debate as to the importance of ventilations in the early minutes of non-asphyxial arrests.
The two respirations providing needed oxygen in the first few minutes is debatable, but the first two respirations showing a patent airway every 20 secs at the end of a cycle is important.
I don't think that's been shown in the research.
If we believe that (i) ventilation is important in the early minutes, and (ii) we need to provide BVM ventilation to verify that the airway is actually patent, and that the delay necessary to perform these tasks outweights the loss of hands-on compression time, then this seems reasonable. I just don't think question has really been answered though.
In the military they drop tubes and never bag them. If supplemental oxygen is being supplied without respiratory support, I would at least like to see a definitive airway in place.
This might be a reasonable solution --- but it creates another issue. Now I have introduced a device that adds airway resistance and PEEP. This is going to have effects too.
It will be interesting to see how these kinds of studies turn out. On one level, I'm concerned that by de-emphasising ETI, and advocating delayed advanced airway placement, that we might see more potentially survivable patients dying from complications of aspiration. I also think it's hard to identify which patients might benefit from ventilatory versus non-ventilatory strategies based on a lot of the situations we encounter prehospitally. I also worry that by removing one of the most common reasons for performing ETI, we're detraining a lot of paramedics who get limited opportunities to intubate. This is not going to help success rates for some RSI programs.
It might be however, that the benefits of continuous CPR in the early minutes of a code might equate to better long-term survival. It remains to be seen. (To me it seems intuitively reasonable just to throw in a King while doing compressions, as soon as someone is free, so we can move to asynchronous compressions, but that's just anecdote).
It's interesting to see how ACLS changes over time.
