TCP for bradycardic ROSC patients

Post-ROSC, your patient may be bradycardic for many reasons, and understanding the possible causes helps guide our treatment. The anoxic hit from cardiac arrest causes hypoxia and acidosis from poor tissue perfusion, both of which can cause bradycardia, and both of which are treated by targeting the SpO2, BP, and CO2 parameters mentioned below. Good airway management for oxygenation and ventilation with attention to SpO2 and ETCO2 targets, and good hemodynamic support with IV fluids and dopamine can be essential to restoring perfusion and improving the hypoxia and acidosis, which will often improve the bradycardia. The bradycardia can also be related to the etiology of the arrest, like a complete heart block that happens spontaneously or in the setting of acute coronary artery occlusion (STEMI). If this is the case ACLS treatments that target the heart rate itself can be helpful (Dopamine, Atropine, TCP). In this case it is also important, if time and stability permit, to obtain a 12-lead ECG to check for STEMI, as these patients can benefit from emergent PCI. So, how do we put it all together?

After ROSC care can be a very challenging time especially when your patient is still not bouncing back to mentation, saturations, or a blood pressure that are in ideal ranges. Such ideal ranges include “avoiding hypotension (MAP <65 mmHg or systolic blood pressure <90 mmHg)…and recommendations to target SpO2 of 92-98% or 94-98%...and current AHA guidelines recommend a normal PaCO2 target of 35-45 mmHg” (Kareemi, Hendin, & Vaillancourt, 2023). You mentioned DOPamine, which is appropriate at a dosing regimen of 5mcg/kg/min, titrating to effect by increasing 5mcg/min/kg every 5 minutes to a max of 20mcg/kg/min. Ideally, “vasoactive drug infusions such as dopamine, norepinephrine, or epinephrine may be initiated if necessary and titrated to achieve a minimum systolic blood pressure of ≥90 mm Hg or a mean arterial pressure of ≥65 mm Hg” (Peberdy, 2010).

Additionally, a fluid bolus is also recommended at 10ml/kg to a maximum of 1000ml if the patient is not showing any signs of fluid overload.

From there, if your ROSC patient remains bradycardic, Atropine should be considered. "Atropine is an antimuscarinic that works through competitive inhibition of postganglionic acetylcholine receptors and direct vagolytic action, which leads to parasympathetic inhibition of the acetylcholine receptors in smooth muscle. The end effect of increased parasympathetic inhibition allows for preexisting sympathetic stimulation to predominate (McLendon, K. & Preuss, C.V., 2023).

Lastly, you are also on the right track with transcutaneous pacing (TCP). This would be a beneficial therapy for a bradycardic patient post-ROSC if they remained hypotensive, HR <50bpm, and other signs of hemodynamic instability. A key point when carrying out TCP would be to ensure that you get mechanical capture as well as electrical, by ideally checking for pulses at the femoral artery site.

A couple of really good resources can be found in our elective CME section. Here are the links to a couple of recordings that speak to after-ROSC care that you may enjoy.

https://mediclearn.rppeo.ca/course/view.php?id=692

https://mediclearn.rppeo.ca/course/view.php?id=652

In summary, the medical directive for Symptomatic Bradycardia may be utilized for both ROSC and non-ROSC patients as needed and deemed appropriate by the attending paramedic. And as always, if ever in doubt or you require further assistance, the BH Physicians are just a quick call away.