What is the best management approach for an adult patient with a history of Acute Kidney Injury (AKI) and Congestive Heart Failure (CHF), currently receiving 0.9% saline infusion at 50 cc, who has shown an increase in BUN to 35 and creatinine to 2.45 from previous levels of 29 and 1.90, respectively?

Management of Worsening Renal Function in a Patient with AKI and CHF History Receiving Normal Saline

Stop the 0.9% normal saline immediately and reassess the patient's volume status clinically—this patient likely has fluid overload from CHF exacerbation causing venous congestion and worsening kidney function, not true hypovolemia requiring continued IV fluids. 1, 2

Critical First Step: Distinguish Congestion from True Hypovolemia

The rising BUN (29→35) and creatinine (1.90→2.45) in a patient with CHF history receiving IV fluids strongly suggests venous congestion-mediated AKI, not hypovolemia requiring more fluids. 2, 3

Immediately assess for signs of fluid overload: 2

• Elevated jugular venous pressure (most important clinical sign)
• Peripheral edema (legs, sacrum)
• Pulmonary congestion (crackles on lung exam, orthopnea, paroxysmal nocturnal dyspnea)
• Daily weight trend (most reliable indicator—compare to baseline)
• Orthostatic vital signs (check supine and standing blood pressure)

If ANY signs of congestion are present, this is NOT dehydration—continuing normal saline will worsen outcomes. 2, 3

Why Normal Saline is Problematic Here

0.9% saline is associated with worse kidney outcomes compared to balanced crystalloids and should be avoided in patients at risk for AKI. 1 The evidence shows biochemical abnormalities and adverse clinical outcomes with normal saline versus more physiological solutions like lactated Ringer's. 1

In CHF patients, renal venous congestion from elevated right-sided heart pressures is a major cause of kidney dysfunction—not inadequate forward flow. 3, 4 Continuing IV fluids worsens this congestion and paradoxically worsens renal function. 2, 3

Immediate Management Algorithm

If Congestion is Present (Most Likely Scenario):

1. Stop IV fluids immediately 2

2. Initiate IV loop diuretics without delay: 2, 5

• Initial dose: At minimum, equal to or exceeding the patient's chronic oral daily furosemide dose (if already on diuretics) 2, 5
• If diuretic-naive: Start with furosemide 20-40 mg IV 5
• Early diuretic intervention is associated with better outcomes—do not delay waiting to see if congestion resolves spontaneously 2

3. Monitor response intensively: 2

• Urine output (target >0.5 mL/kg/h initially)
• Daily weights at same time each day
• Fluid intake and output every shift
• Daily electrolytes, BUN, creatinine 2, 6
• Clinical signs of perfusion and congestion

4. Titrate diuretic dose based on response: 5

• If inadequate diuresis after 6-8 hours, increase dose by 20-40 mg 6
• Can escalate up to 600 mg/day in severe cases with careful monitoring 6
• Consider continuous infusion if boluses ineffective 5

If True Hypovolemia is Confirmed (Less Likely):

Only if NO signs of congestion AND clear evidence of hypovolemia (orthostatic hypotension, low JVP, dry mucous membranes): 2

• Continue IV fluids at 50 mL/hour (current rate is appropriately conservative) 2
• Switch from 0.9% saline to balanced crystalloid (lactated Ringer's or isotonic bicarbonate) 1
• Monitor meticulously for development of congestion 2
• If any congestion develops, immediately start diuretics 2

Critical Monitoring During Treatment

Daily requirements: 2

• Body weight (same time, same scale)
• Strict intake/output
• Vital signs including orthostatics
• Serum electrolytes, BUN, creatinine (daily during active management) 2, 6
• Clinical exam for perfusion and congestion signs

Watch for electrolyte depletion: 6

• Hypokalemia (most common—may need supplementation)
• Hyponatremia, hypomagnesemia, hypocalcemia
• Signs: weakness, lethargy, muscle cramps, arrhythmias 6

Medication Management

Maintain guideline-directed medical therapy unless contraindicated: 2

• Continue ACE inhibitors/ARBs and beta-blockers in absence of hemodynamic instability 2
• Do NOT substitute ACE inhibitors for diuretics—this leads to pulmonary and peripheral congestion 1, 7
• Diuretics should be combined with ACE inhibitors and beta-blockers, not used alone 1, 5

Understanding the Creatinine Rise

A rise in creatinine during decongestion therapy is often acceptable and associated with IMPROVED long-term survival if it represents successful fluid removal rather than tubular injury. 3 This is fundamentally different from AKI due to sepsis or nephrotoxins. 3

Do not be overly concerned about mild azotemia if: 2

• Patient is becoming less congested clinically
• Urine output is adequate
• Patient remains asymptomatic
• No signs of severe electrolyte depletion

However, if creatinine continues rising despite decongestion, consider: 8

• Intrinsic kidney injury (acute tubular necrosis)
• Nephrotoxic medications
• Need for renal replacement therapy consultation

Common Pitfalls to Avoid

1. Continuing IV fluids in a congested patient 2, 3

• This is the most common error—fluid overload worsens kidney function in CHF patients through venous congestion 3, 4

2. Delaying diuretic therapy when congestion is present 2

• Waiting to see if congestion resolves spontaneously leads to worse outcomes 2
• Early intervention in emergency or outpatient settings improves hospitalized patient outcomes 2

3. Using 0.9% saline instead of balanced crystalloids 1

• Normal saline is associated with worse kidney outcomes and should be avoided 1

4. Stopping ACE inhibitors/ARBs prematurely 2

• These should be maintained unless hemodynamically unstable 2

5. Using diuretics alone without other heart failure medications 1, 5

• Diuretics control symptoms but do not improve long-term prognosis without ACE inhibitors and beta-blockers 1

When to Escalate Care

Consider nephrology consultation if: 8

• Creatinine continues rising despite appropriate management
• Severe electrolyte abnormalities develop
• Oliguria persists (<0.3 mL/kg/h for >24 hours)
• Fluid overload refractory to high-dose diuretics
• Need for renal replacement therapy consideration

The key principle: In CHF patients with rising creatinine, venous congestion is the enemy—not inadequate fluid administration. 3, 4 Decongestion with diuretics, even if it temporarily raises creatinine, improves long-term kidney function and survival. 3