Postoperative Day 1: Tachycardia, Oliguria, and Hypotension
A 68-year-old man is on postoperative day 1 following an open hemicolectomy. He has a history of hypertension and type 2 diabetes. His current vital signs are: temperature 37.8°C, heart rate 118 bpm, blood pressure 92/54 mmHg, respiratory rate 24 breaths/min, and oxygen saturation 94% on room air. His urine output over the past 4 hours is 60 mL. He has received 3 L of IV fluids since surgery. He is drowsy but arousable. His abdomen is distended, and he reports nausea. His serum lactate is 3.2 mmol/L (normal <2.0). His white blood cell count is 14,000/µL. The surgical team has ordered a fluid bolus of 500 mL normal saline over 1 hour.
1. Calculate the patient's urine output in mL/kg/hr if he weighs 80 kg. Is this adequate? What is the priority nursing action?
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Urine output = 60 mL / (80 kg × 4 hr) = 60 / 320 = 0.1875 mL/kg/hr. This is well below the normal minimum of 0.5 mL/kg/hr, indicating oliguria and inadequate renal perfusion. The priority nursing action is to recognize signs of hypovolemic or septic shock (tachycardia, hypotension, oliguria, elevated lactate) and immediately escalate to the surgical team while initiating the ordered fluid bolus. The nurse should also monitor vital signs frequently, assess for signs of sepsis (fever, elevated WBC, tachycardia), and prepare for possible transfer to a higher level of care.
2. What additional assessment findings would help differentiate hypovolemia from sepsis in this patient?
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Differentiating hypovolemia from sepsis requires a focused assessment:
- Skin: Hypovolemia may cause cool, clammy skin; sepsis may cause warm, flushed skin initially (early sepsis) or cool skin in late septic shock.
- Capillary refill: Prolonged (>3 seconds) in both, but may be brisk in early sepsis.
- Mental status: Both can cause altered mental status, but sepsis often causes more pronounced confusion.
- Hemodynamics: Hypovolemia typically responds to fluid bolus with improvement in BP and heart rate; sepsis may require vasopressors if hypotension persists after fluids.
- Labs: Sepsis often shows rising lactate, leukocytosis or leukopenia, and possibly thrombocytopenia. Hypovolemia may show hemoconcentration (elevated hematocrit) and prerenal azotemia (elevated BUN/creatinine ratio).
- Source of infection: Look for surgical site, urinary catheter, IV lines, or lungs for signs of infection.
3. The patient's blood pressure remains 88/50 mmHg after the 500 mL bolus. What is the next most appropriate action?
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The patient remains hypotensive despite fluid resuscitation, indicating possible septic shock or ongoing hypovolemia. The nurse should:
- Notify the surgical team immediately and request further orders.
- Prepare for vasopressor therapy (e.g., norepinephrine) as ordered, ensuring adequate IV access (preferably central line).
- Continue fluid resuscitation as ordered (may repeat bolus).
- Monitor lactate and urine output closely.
- Obtain blood cultures before starting antibiotics if not already done.
- Prepare for possible transfer to ICU. The nurse should not delay escalation. The Surviving Sepsis Campaign recommends 30 mL/kg crystalloid for initial resuscitation and vasopressors if hypotension persists.