Hemorrhagic Shock From Suspected Hemoabdomen
At 18:30, a 32 kg, 8-year-old male Labrador retriever is presented after acute collapse during a game of fetch. The owner reports the dog ran into the house and fell over. On examination: pale mucous membranes, heart rate 190 beats/min with weak femoral pulses, respiratory rate 48 breaths/min, systolic blood pressure 68 mmHg by Doppler, and a distended abdomen with a fluid wave. PCV is 38%, total solids 5.6 g/dL, blood lactate 7.2 mmol/L, and glucose 90 mg/dL. The clinic has 0.9% saline, lactated Ringer's solution, 7.5% hypertonic saline, and one unit of 250 mL packed red blood cells; no fresh frozen plasma. The veterinarian suspects hemoabdomen from a splenic mass and asks the technician to start resuscitation while the surgeon is called in. The dog has no known heart disease.
1. Calculate an initial crystalloid bolus and explain why a full 90 mL/kg shock dose is inappropriate here. Include the role of hypertonic saline and blood products.
Read the worked answer
A standard initial crystalloid bolus is 20 mL/kg: 32 kg x 20 mL/kg = 640 mL over 15 to 20 minutes, then reassess. Do not give a 90 mL/kg shock dose in this dog. Hemoabdomen is not controlled, and massive crystalloid dilutes clotting factors and red cells, lowers temperature, and can disrupt clot. Target systolic blood pressure around 80 to 90 mmHg, or mean arterial pressure 60 to 65 mmHg, until surgery. Hypertonic saline 7.5% at 4 mL/kg equals 128 mL over 10 to 15 minutes and can buy time, but it must be followed by crystalloid and is contraindicated if hypernatremia is present. Blood products are preferred. One 250 mL unit of packed red blood cells is only about 8 mL/kg for this dog, so type or crossmatch and call for more. Reassess after each bolus rather than giving a fixed total.
2. The PCV is 38%, which the owner interprets as normal. Explain why this does not rule out major hemorrhage and what monitoring should follow.
Read the worked answer
In acute hemorrhage, whole blood is lost, so PCV and total solids can remain near normal for hours. The PCV falls later as interstitial fluid shifts into the vasculature and after crystalloid resuscitation. A PCV of 38% does not rule out 30% to 40% blood loss. The lactate of 7.2 mmol/L, weak pulses, and prolonged capillary refill are better shock indicators. Repeat PCV and total solids after fluids and monitor for a falling PCV. Type or crossmatch before transfusion; DEA 1.1 typing is standard, and a crossmatch is ideal if time permits. Continue to monitor blood pressure, heart rate, pulse quality, lactate clearance, and urine output.
3. List the signs of overhydration or volume overload the technician should watch for during resuscitation and explain why they matter.
Read the worked answer
Watch respiratory rate and effort, auscult for crackles, check for serous nasal discharge, and monitor central venous pressure if available. A sudden increase in respiratory rate, new cough, or frothy nasal discharge suggests pulmonary edema; stop the bolus and notify the veterinarian. Also monitor urine output, PCV and total solids, lactate clearance, and blood pressure. Overzealous boluses can worsen hypothermia and dilutional coagulopathy. Reassess after every 10 to 20 mL/kg rather than giving a fixed total, and document each bolus and the response.