How do I manage a patient two hours after ureteroscopic laser lithotripsy (URSL) who now has hypotension and tachycardia with a normal temperature?

Management of Post-URSL Hypotension and Tachycardia

Immediate Assessment and Stabilization

This patient requires immediate bedside assessment to determine hemodynamic stability and identify the underlying cause of hypotension, as unstable patients with end-organ dysfunction require high-acuity care. 1

Critical First Steps (Within 5 Minutes)

• Perform passive leg raise (PLR) test immediately to determine if hypotension is fluid-responsive before reflexively administering fluids, as only 50% of hypotensive patients respond to fluid boluses 1, 2
• Obtain vital signs in both arms, assess for end-organ dysfunction (altered mental status, oliguria, cold extremities, decreased capillary refill) 2, 3
• Perform focused physical examination to categorize shock type: check for warm vs. cold extremities, jugular venous distension, pulmonary congestion 2
• Obtain immediate 12-lead ECG to exclude arrhythmias or acute myocardial ischemia 2, 3

Urgent Laboratory and Imaging

• Draw arterial blood gas and serum lactate immediately as markers of tissue perfusion and shock severity 3
• Obtain complete blood count (to assess for bleeding), comprehensive metabolic panel, and renal function tests 3
• Perform bedside ultrasound (FAST exam) urgently to identify free intraperitoneal fluid suggesting bleeding or bladder perforation 3, 4
• Consider bedside echocardiography to evaluate cardiac output, volume status, and guide therapy selection 2, 3

Differential Diagnosis and Treatment Algorithm

Most Likely Causes Post-URSL

1. Occult Bleeding/Hypovolemia (Most Common)

• If PLR test is positive (blood pressure improves with leg elevation): Administer 250-500 mL crystalloid bolus (0.9% saline or lactated Ringer's) rapidly 2, 3
• Monitor hematocrit serially, but do not rely on single measurement as initial hematocrit has low sensitivity for detecting hemorrhage 3
• If bleeding suspected on ultrasound with hemodynamic instability despite fluid resuscitation, proceed directly to surgical exploration 3
• Commence continuous bladder irrigation immediately if hematuria present to prevent clot retention, which can be catastrophic in post-lithotripsy patients 4

2. Sepsis/Urosepsis (Second Most Common)

• Normal temperature does NOT exclude sepsis in the immediate postoperative period 5
• If PLR test is negative and patient has warm extremities with low blood pressure: Start norepinephrine 8-12 mcg/minute (dilute 4 mg in 1000 mL D5W, infuse at 2-3 mL/min) via large vein or central access 2, 6
• Obtain blood and urine cultures immediately before antibiotics 5
• Administer broad-spectrum antibiotics covering aerobes and anaerobes (2nd or 3rd generation cephalosporin) 1

3. Vasodilation from Anesthesia/Epidural

• If epidural analgesia was used and patient is normovolemic (negative PLR): Administer vasopressors (norepinephrine preferred) rather than fluids 1, 2
• Target mean arterial pressure 70-100 mm Hg or within 70-100% of baseline 1

4. Cardiac Complications (Less Common but Critical)

• If cold extremities, cyanosis, decreased mentation, or pulmonary congestion present: suspect cardiogenic shock 2
• Do NOT administer beta-blockers as they worsen pump failure in low output states 2
• Consider dobutamine 2-5 mcg/kg/min if low cardiac output confirmed on echocardiography 2

Specific Treatment Protocols

Fluid Resuscitation (If PLR Positive)

• Administer 250-500 mL crystalloid bolus over 10-15 minutes 2, 3
• Reassess after each bolus; avoid fluid overload which delays recovery and increases complications 1
• Target pulmonary wedge pressure <20 mm Hg and cardiac index >2 L/min/m² 3

Vasopressor Therapy (If PLR Negative)

• Norepinephrine is first-line: Dilute 4 mg in 1000 mL D5W (4 mcg/mL concentration), start at 2-3 mL/min (8-12 mcg/min) 2, 6
• Titrate to maintain systolic BP 80-100 mm Hg or MAP >65 mm Hg 1, 6
• Avoid phenylephrine as first-line unless tachycardia is prominent, as reflex bradycardia can worsen cardiac output 2
• If hypotension persists despite norepinephrine, add vasopressin or consider epinephrine 0.05-0.5 mcg/kg/min 2

Monitoring Requirements

Continuous Monitoring (First 24-48 Hours)

• Continuous ECG, blood pressure, oxygen saturation monitoring 1, 2
• Hourly urine output measurement (target >0.5 mL/kg/hr) 2, 3
• Serial lactate measurements every 2-4 hours until normalizing 2, 3
• Consider invasive arterial line if requiring vasopressors or frequent blood pressure measurements 1
• Right heart catheterization or intraoperative TEE may be useful for continuous optimization of loading conditions 1

Escalation Criteria

• Transfer to ICU if requiring vasopressors, mechanical ventilation, or showing signs of end-organ dysfunction 1
• Consider mechanical circulatory support if high-dose vasopressors fail to maintain blood pressure 2

Critical Pitfalls to Avoid

• Do NOT reflexively administer fluids without PLR testing, as this worsens outcomes in approximately 50% of non-hypovolemic patients 1, 2
• Do NOT ignore severe hematuria post-URSL; failure to institute continuous bladder irrigation can lead to clot retention and bladder rupture 4
• Do NOT rely on normal temperature to exclude sepsis in the immediate postoperative period, as urosepsis can present with normothermia initially 5
• Do NOT use saline alone for norepinephrine dilution; must use dextrose-containing solutions to prevent oxidation and loss of potency 6
• Avoid abrupt withdrawal of vasopressors; reduce gradually once blood pressure stabilizes 6
• If bladder rupture suspected (abdominal distension, ileus), obtain CT with contrast rather than ultrasound, which may miss perforation 4

Procedure-Specific Considerations

• Operative duration >90 minutes significantly increases severe adverse event risk (OR 1.58-4.28) 5
• High intrarenal pressures and temperatures during laser lithotripsy can cause ureteral injury and subsequent complications 7, 8, 9
• Bladder spasms during lithotripsy can trigger autonomic dysreflexia and severe hypertension followed by rebound hypotension 4