“We Got A Pulse Back! LET'S GO!!” The Vulnerability of ROSC.
“When you think you’re safe is precisely when you’re most vulnerable.” – Kambei Shimada, Akira Kurosawa’s The Seven Samurai
The first few minutes after you obtain a return of spontaneous circulation (ROSC) is a very delicate time. There is an intrinsic desire to strap the patient to a long board and fly like hell to the hospital. If you deliver the patient with a pulse... it’s a save.... right? Resuscitation is not just regaining a pulse, it extends into the rest of their treatment.
We need to re-evaluate our priorities and take some time to stabilize this patient before we start trekking to the hospital. Most cardiac arrests are not performed in the back of an ambulance. My service specifically does not transport cardiac arrests unless either ROSC is obtained, or certain situations in which a certain intervention is believed to be of benefit. How fast you move the patient to your ambulance is going to obviously depend on the environment and circumstances surrounding your resuscitation. But before you decide to hit the road, make sure you have stabilized your patient. Here are a few concepts to reflect on after the patient has obtained a pulse.
Blood Pressure The AHA recommends a 1-2 liter bolus post arrest if the systolic pressure is below 90mmHg. I have a few reservations with this recommendation.
1. As clinicians we shouldn’t be making decisions based just off a systolic pressure. Depending on heart rate, we will only spend roughly 1/3 of our time in systole. Mean Arterial Pressure (MAP) is the number we should be using as a surrogate of adequate perfusion. Our goal initially should be to maintain the MAP > 65mmHg. Check out Sam Irelands post on why MAP is better than just looking at systolic pressures. Click here
2. It is uncommon for someone to go into a non traumatic cardiac arrest from hypovolemia. Unless you suspect a cholera outbreak...more fluid is probably not the answer.
3. A patient who returns from arrest in a hypotensive state should be assumed to be in cardiogenic shock until proven otherwise. It is very unlikely that a provider would empirically administer two liters of fluid to a patient with decompensating cardiogenic shock without expecting deleterious consequences. The Starling curve helps us understand that there is a certain point in which increasing preload has no affect on stroke volume (SV). The beginning of the curve is when SV is "preload dependent." So what does this mean? We shouldn't waist valuable time with a non perfusing MAP waiting for fluids to "kick in." Time spent with inadequate end organ perfusion increases post resuscitation complications and mortality. Defend the MAP!
Pressors Instead of falling back on the “fill em before you squeeze em” mentality. Ask yourself “where did they lose the fluid?” I commonly see fluid challenges being done where pressor challenges are more appropriate. Levophed is usually my primary pressor if a bump in MAP is needed after ROSC. Here’s why;
1. The venous system is a capacitance system. Which means it has a certain amount of unstressed volume that can be converted to stressed volume to provide an intrinsic fluid bolus. This is especially true following a state of venous-stasis that occurs during cardiac arrest. Levophed causes this unstressed to stressed volume reaction when administered. This reduces the amount of fluid that was formally taught as “needed” before starting a pressor.
2. Levophed has limited beta 1 properties. Which makes it very desirable after ROSC. Depending on how many rounds of epinepherine were administered, it is very likely that your patient will initially be tachycardic after obtaining a pulse. Increased chronotropic response will increase myocardial oxygen demand and is not always desirable in the freshly revived heart. There is obviously patients who will present post ROSC with bradycardia. Depending on the severity and surrounding hemodynamics, epinephrine would be my first line pressor if an increase in chronotropic response was desired. It would be important to start off in a mid 5-10 mcg/Min range. Lower dose can cause increased Beta 2 influence and subsequently drop vascular tone.
Ventilation The way we ventilate a patient after ROSC can literally make or break our success in resuscitation. Here are my three tips to assure optimization of ventilation/oxygenation.
1. Strict tidal volume control is extremely important. Visualizing that the heart is sandwiched between the lungs, helps drive home the consequences that can occur during hyperinflation. Remember that Cerebral drainage is impaired when ITP increases. I recommend putting the patient on a advanced parameter ventilator as soon as possible. If forced to use a BVM, keep in mind that the BVM is a one hand device after an advanced airway is in place.
Check out the podcast I did with Eric Bauer from FlightBridge ED on the curse that is BVM ventilation! Click Here
2. It is not uncommon for pulmonary edema to occur post resuscitation. If you are having a difficult time oxygenating the patient, always consider applying Henry’s Law and utilizing PEEP.
3. Not every patient who obtains ROSC needs 100% Fi02. We should carefully titrate the Sp02 to avoid reperfusion and oxidative injury. AHA recommends maintaining a saturation between 94-99%.
This vulnerable time is where a true resuscitationist shines. The process of running rounds of ACLS for a cardiac arrest is easy. The real work starts after you regain a pulse!
1.Kang D, Kim J, Rhee JE, et al. The risk factors and prognostic implication of acute pulmonary edema in resuscitated cardiac arrest patients. Clinical and Experimental Emergency Medicine. 2015;2(2):110-116. doi:10.15441/ceem.14.016.
2.Neumar RW, Nolan JP, Adrie C, et al. Post Cardiac Arrest Syndrome. Circ.2008;118:2452 2483.
4.Fluid infusion during CPR and after ROSC—Is it safe?Soar, JasmeetFoster, JaneBreitkreutz, Raoul et al. Resuscitation , Volume 80 , Issue 11 , 1221 - 1222