Hypovolemia as a H&T Cause of Cardiac Arrest
When a patient loses excessive amounts of fluids, we say that they’re in a state of hypovolemia. As we work a code we’ll consider possible reversible causes commonly referred to as Hs & Ts. Hypovolemia as a H&T cause of cardiac arrest is today’s Pass ACLS tip topic.
Causes of Hypovolemia
Fluid loss can occur from a variety of reasons.
The most obvious cause of hypovolemia is from bleeding. Blood loss decreases the circulating volume as well as the oxygen carrying capacity and clotting components of blood. Bleeding can be internal or external as well as traumatic, pathogenic, or iatrogenic. Iatrogenic causes include any recent invasive procedure, such as dialysis, surgery, or PCI.
Blood isn’t the only fluid loss that can result in hypovolemia. Excessive or prolonged vomiting, diarrhea, severe burns, severe heat exhaustion, or dehydration can also cause hypovolemia.
Signs & Symptoms of Hypovolemia
Identifying a mechanism of injury or possible causes of blood (or other fluid loss ) via a medical history and reviewing signs or symptoms before the patient arrested can help us identify potential causes of hypovolemia.
Classic Signs and symptoms of shock that may lead us to suspect hypovolemia include:
- Tachycardia;
- anxiety;
- pale/cool/moist skin;
- decreased capillary refill;
- falling BP; and
- decreasing level of consciousness.
Treatment of Hypovolemia
If we suspect hypovolemia as a cause of cardiac arrest, the treatment is to administer fluids to replace those that have been lost. Unless there’s a reason like renal failure or pulmonary edema, an IV of Normal Saline should be started and running wide open during every cardiac arrest. This will temporarily expand the circulating volume.
Crystalloid solutions like Lactated Ringers and Normal Saline take three times the volume to replace lost blood and don’t carry oxygen. Patients with fluid loss for reasons other than bleeding, will benefit most from wide open crystalloid IV solutions.
If we suspect blood loss, replacement of red blood cells and clotting factors is needed via administration of whole blood or blood products. During your megacode, if you suspect blood loss from internal or external bleeding, you should run the IV wide open, get STAT labs, and can simply state that you would administer blood per your organization’s transfusion policy.
