In yesterday’s blog article I went over how to estimate blood loss in trauma patients based on their vital signs.* It is, of course critical to rule out the other less common causes of post traumatic shock/hypotension (tension pneumothorax, cardiac tamponade, neurogenic shock).
When blood loss is determined to be the cause of shock after trauma the patient requires fluid replacement with Normal Saline or Ringer’s Lactate and/or blood and blood products.
Simultaneously, external bleeding must be promptly controlled usually with direct pressure and internal bleeding must be management by prompt surgical therapy. So if surgical therapy is not available at the current hospital, arrangements must be promptly made to transfer the patient to a trauma center following appropriate stabilization (for example, airway protection if indicated.
So once the hypotensive trauma patient’s airway and breathing are assessed and managed, treatment of hypovolemic bleeding is addressed.
First, two large bore IV catheters are inserted into the antecubital veins (minimum size is 16 gauge) and blood is drawn for CBC, lytes, BUN and creatine, coagulation studies, blood for type and cross, and a pregnancy test for all females of child-bearing age.
An initial warmed fluid bolus of 1 to 2 liters is given rapidly to adults and 20 mg/kg for pediatric patients.
“The patient’s response to initial fluid resuscitation is the key to determing subsequent therapy.”*
There are three possible patterns of response to the initial fluid bolus: rapid response, transient response, and minimal or no response.
These patients respond rapidly and favorably to the initial fluid bolus with hemodynamic normalization. And they remain stable when IV fluids are decreased to maintenance. Usually these patients have lost less than 20% of their blood volume. And they don’t need addition fluid boluses or blood transfusion. They do, however, need to be typed crossed for blood if needed.
However, it is still critical to ensure that surgical consultation be obtained immediately as emergency surgery may become suddenly necessary.
These patients respond to the initial fluid bolus with improvement in their vital signs and improvement in perfusion. But when the bolus infusion is slowed to maintenance their vitals and perfusion deteriorate.
These patients either have continuing blood loss or they need more fluid and/or blood. Usually these patients have lost 20% to 40% of their blood volume.
They need blood and blood products and they need immediate surgical or angiographic control of internal hemorrage.
Minimal or No Response
These patients have minimal or no response to fluid bolus and blood administration. They need immediate surgical or angiographic control of internal or they will die.
In patients with minimal or no response to fluid bolus, it is important to consider other causes of failure to respond to fluids and blood (namely pump failure caused by cardiac contusin, cardiac tamponade, and tension pneumothorax) but they are uncommon. By far the most common cause of minimal or no response to fluids and blood is exasanguinating hemorrhage.
Fully crossmatched blood is best for transfusion but it takes the blood bank about an hour to prepare.
Type specific blood can obtained much faster from the blood bank, usually within ten minutes then fully crossmatched blood. Type specific blood should be used for transient responders.
Non-responders need immediate type-specific blood if available. If type-specific blood is not immediately available, then type O packed cells are needed for patients who are bleeding to death.
A foley catheter is placed in the urinary bladder to monitor urine output as one of indicator’s of an adequate response to fluid resuscitation and improved end-organ perfusion. Other evidence of a favorable response to fluid resuscitation are increased level of consciousness and improved peripheral perfusion (both are also indicators of improved end-perfusion and improved oxygenation).
Gastric Dilatation and Decompression
Trauma patients often experience gastric dilatation that can cause unexplained hypotension, respiratory compromise, and cardiac arrhythmias. Pass an orogastric or nasogastric into the stomach and connect to suction to decompress the stomach.
*Advanced Trauma Life Support Student Course Manual,9th ed, 2013, American College of Surgeons, pp. 72-74.