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My approach<\/b><\/h2>\n
We all know the\u00a0ABCs of resuscitation<\/a>, but A doesn\u2019t always come first. Asthma is a respiratory problem not an airway problem. Unless the patient arrives in arrest, there is no reason to intubate immediately. Adding plastic to the airway only makes things worse.<\/span><\/p>\n The immediate action is to start oxygen and bronchodilators. In the severely ill asthmatic I don\u2019t spend too much time debating the finer points of evidence based medicine. Give both albuterol (salbutamol for most countries) and ipratropium bromide. Also, stick to nebulizers in these patients.<\/span><\/p>\n After oxygen and bronchodilators are started, my nurses start hooking the patient to the monitor and place\u00a02 IVs. (This often occurs simultaneously, as we have a large team in resus. However, if you are working with a smaller staff prioritize the breathing meds over the IV.) Essentially all patients with severe asthma are dehydrated and they are also prone to hypotension when switched to positive pressure ventilation. I start a 20ml\/kg bolus of my favorite crystalloid as soon as I have IV access.<\/span><\/p>\n The definitive treatment of all asthma patients is <\/span>corticosteroids. <\/b>EBM nerds will talk forever about oral and parenteral steroids being equivalent, but these patients are all getting their steroids IV. The biggest question is timing. Steroids will take a minimum of 6 hours to have a noticeable effect. Therefore, they are unlikely to help you in the resus room, but the earlier they are given the earlier then are able to work. In the critically ill asthma patient, there may be other therapies to prioritize over a medication that won\u2019t make an immediate difference. Instead of a nurse being tasked with getting steroids, you might need RSI medications, IV fluids, vasopressors, or help setting up non-invasive ventilation. Focus on the therapies that will help this dying patient immediately first, but get a dose of intravenous steroids on board as soon as you have a free minute. Any corticosteroid should be fine, such as methylprednisolone 125mg IV or hydrocortisone 100mg IV.<\/span><\/p>\n The final medication that I will <\/span>routinely<\/span><\/i> include in the management of life threatening asthma is <\/span>magnesium<\/b>. That may be a controversial statement and I certainly don\u2019t use magnesium in asthma patients that aren\u2019t actively dying, but there is a modicum of evidence and it seems like the sicker you are the more likely magnesium is to help you. The dose of magnesium sulfate is 2 grams IV repeated up to 3 times in the first hour.<\/span><\/p>\n If the patient is not improving with these first line therapies, I consider two second line medications: epinephrine and ketamine.<\/span><\/p>\n Epinephrine<\/b><\/p>\n Epinephrine has a theoretical advantage for asthmatics who have not quickly responded to beta-2 agonists: it will act as an alpha agonist which may help decrease airway edema as well as providing additional beta-2 agonism. Epinephrine can be safely given to asthmatic patients of any age. (Cydulka 1998 ) Some practitioners will use terbutaline instead of systemic epinephrine, and that is reasonable, but I prefer epinephrine because it is a common medication we are all very comfortable dosing, it adds alpha effects, and I can provide push doses if needed<\/a>.<\/span><\/p>\n Nebulised epinephrine<\/b><\/p>\n Systemic epinephrine<\/b><\/p>\n Ketamine (+\/- Delayed Sequence Intubation)<\/b><\/p>\n If the patient is agitated (probably secondary to hypoxia) ketamine is my agent of choice, theoretically as part of a\u00a0delayed sequence intubation<\/a>. Ketamine is used to treat the agitation, allow for proper pre-oxygenation of the patient and get the rest of the medications on board. Non-invasive positive pressure ventilation can be used as part of this pre-oxygenation. The plan is to use ketamine to pre-oxygenate and buy time to prepare for a safe, controlled intubation. All intubation equipment is at the bedside. However, there are reports of patients improving after the combination of ketamine and BiPAP, obviating the need for intubation. <\/span><\/p>\n If the patient is not improving with maximal medical management, it is time to start thinking about positive pressure ventilation and intubation. A common teaching is: when thinking about intubating an asthma patient, wait, and then wait some more, and then continue to wait, but don\u2019t wait too long. If you are considering intubation, BiPAP should almost certainly be tried first. Remember that putting a piece of plastic in the trachea does nothing to help these patients. In fact, it increases airway resistance and dead space. The reason you considering intubation is because of respiratory fatigue and BiPAP can provide exactly the pressure support that these patients need. <\/span><\/p>\n How to use NIPPV<\/span><\/p>\n If the NIPPV doesn\u2019t work and you have waited longer than you feel comfortable, it may be time to intubate the patient. In emergency medicine, we love the airway, but asthma is one scenario that we should be wary of grabbing a laryngoscope. Why? Well, in addition to the normal critical care sympathetic tone that we will obliterate with our sedative, these patients are generally hypovolemic and have significant lung hyperinflation limiting venous return that sets them up for hemodynamic collapse. Add to that hypercapnea, acidosis, and hypoxia and it is not hard to understand why the chances of a peri-intubation arrest<\/a> are so high.<\/span><\/p>\n So how should you pass the tube<\/a>?<\/span><\/p>\n There are some reasonable arguments to be made for an awake intubation, however, in this critically ill patient I want to stay within my comfort zone and ensure I am ideally set up for first pass success. Therefore, I use <\/span>rapid sequence intubation<\/b>. First, I prepare for post-intubation hypotension. I have a fluid bolus going. Either my nurse has prepared an epinephrine drip (if it wasn\u2019t already running) or I have push dose epinephrine drawn up and ready. I have also pre-set my ventilator so there aren\u2019t any mistakes.<\/span><\/p>\n Rapid Sequence Intubation<\/b><\/p>\n Unfortunately, passing the tube is not the end of your problems, but only the beginning. We often ignore the vent and allow our RTs to be the experts. This is a situation where the wrong vent settings can kill the patient. She is at risk for barotrauma, volutrauma, and hemodynamic compromise from impaired venous return. The ventilator settings are essential.<\/span><\/p>\n Ventilator Settings<\/b><\/p>\n Finally, if despite all of the above your patient still looks like she is going to die, there are two rescue options to consider: inhalational agents and ECMO.<\/p>\n Inhalational agents (isoflurane or sevoflurane)<\/b><\/p>\n These are very effective bronchodilators. Talk to your anesthesia colleagues. They are usually happy to help.<\/span><\/p>\n ECMO<\/b><\/p>\n Removing the lungs from the equation while continuing to treat the underlying inflammation and bronchospasm certainly seems to make sense. There are obviously no randomized control trials to support the practice, but there are a number of case reports. It is probably worth getting your local ECMO team on the phone.<\/span><\/p>\n\n
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![\"Summary](\"https:\/\/i0.wp.com\/first10em.com\/wp-content\/uploads\/2015\/08\/first10em-asthma-ventilator-settings-summary.png?resize=660%2C495&ssl=1\")
<\/a>
![\"first10em](\"https:\/\/i0.wp.com\/first10em.com\/wp-content\/uploads\/2015\/08\/first10em-severe-asthma-summary.png?resize=660%2C413&ssl=1\")
<\/a><\/p>\n