EMS Protocol of the Week - General Cardiac Arrest Care (Non-Traumatic) (Adult)

The prehospital approach to general cardiac arrest care is a good introduction to the progression of responsibilities from one level of training to the next. We get a large number of OLMC calls from our own paramedics requesting physician input in arrest cases, so it’s always good to refresh ourselves on what they can or cannot do in these instances.

Note that everything in the attached protocol is Standing Order, which, as a reminder, consist of the steps that EMS providers should be performing by default without any additional physician input.

At the CFR level, providers who encounter a patient in arrest will initiate CPR and apply an Automated External Defibrillator, following the AED’s instructions until backup arrives.

BLS providers (EMTs) will request ALS backup if not already present, but will otherwise begin to transport the patient to the hospital after 3 rounds of CPR/AED analysis.

It’s not until the ALS (paramedic) level that an actual cardiac monitor will be applied, giving a specific rhythm underlying the arrest. It’s for this reason that you might hear something from the paramedics like “our initial rhythm was asystole; patient was shocked 2 times (by AED) prior to our arrival.” From there, paramedics will branch off into separate protocols based on the specific type of arrest, each consisting of their own Standing Orders and Medical Control Options.

Can’t wait to find out more specifics? Tune in next week for more cardiac arrest talk! Or, for spoilers, there’s always www.nycremsco.org and the protocol binder!

Dave

ARDS

Acute respiratory distress syndrome (ARDS) 

acute inflammatory lung injury that causes non-cardiogenic pulmonary edema by increasing alveolar capillary permeability. 

The thickened diffusion barrier leads to hypoxemia via:

decreased lung compliance

inefficient gas exchange

Pulmonary hypertension

increased physiological dead space

Predisposing factors:

Direct lung injury: pneumonia, gastric aspiration, pulmonary contusion, near drowning, inhalation injury, transfusion-related acute lung injury

Indirect lung injury: sepsis, shock, acute pancreatitis, burns, crush injury, fat embolism, and massive transfusion

Diagnosis criteria for ARDS – Berlin definition (all 4 components must be present):

1. Acute onset (1 week or less)

2. Hypoxemia (PF ratio* < 200 mmHg with a minimum of 5 cmH2O PEEP (or CPAP))

3. Pulmonary edema (bilateral opacities on CXR)

4. Non-cardiogenic (not caused by cardiac failure)

*PF (PaO2/FiO2) ratio is the ratio of arterial oxygen partial pressure to fractional inspired oxygen. PaO2 value can be obtained from ABG, and FiO2 is 0.21 at sea level (room air) or depends on supplemental O2.

ARDS is a diagnosis of exclusion so consider first: 

Cardiogenic pulmonary edema, severe multilobar pneumonia, acute exacerbation of pulmonary fibrosis, diffuse alveolar hemorrhage, idiopathic acute eosinophilic pneumonia, dissemination of lymphoma/leukemia, and several others. 

Workup:

Labs: CBC, BMP, LFTs, Coags, VBG followed by ABG, troponin, BNP, lipase, consider DD

Imaging: CXR, POCUS US ECHO and CHEST and consider CT

ED Management:

Supplemental O2

Treat the underlying condition (pneumonia, sepsis, etc.)

Tempered diuresis – non-cardiogenic pulmonary edema takes much longer to respond to treatment than cardiogenic CHF, so avoid being overly aggressive with diuresis, as this may worsen underlying shock and increase likelihood of multi-organ failure

Glucocorticoids — consider steroids when ARDS precipitated by a steroid-responsive process (eg, acute eosinophilic pneumonia)

Be cautious when using non-invasive positive pressure ventilation – the benefit of NIPPV in the initial management of ARDS remains controversial. 

Mostlikely patient will end up being intubated, for vent management suggested strategies are:

Use low tidal volume (6-8 mL/kg) to avoid barotrauma (ideal body weight should be calculated)

And careful FiO2:PEEP ratio titration:

ARDS severity (mortality) predictor 

Mild ARDS – The PaO2/FiO2 is >200 mmHg, but ≤300 mmHg, on ventilator settings that include positive end-expiratory pressure (PEEP) or continuous positive airway pressure (CPAP) ≥5 cm H2O

Moderate ARDS – The PaO2/FiO2 is >100 mmHg, but ≤200 mmHg, on ventilator settings that include PEEP ≥5 cm H2O

Severe ARDS – The PaO2/FiO2 is ≤100 mmHg on ventilator settings that include PEEP ≥5 cm H2O.