17.3 Acute Kidney Injury and Chronic Renal Failure
Key Takeaways
- Sort acute kidney injury as prerenal, intrinsic, or post-renal before you hang a liter or ignore a Foley catheter.
- Hyperkalemia with electrocardiogram changes gets intravenous calcium to stabilize membranes, then insulin with dextrose and nebulized albuterol; dialysis removes the potassium.
- A missed dialysis run brings potassium, volume overload, and possible uremic pericardial effusion—not another keep-open liter.
- Never put a cuff, line, or tourniquet on an arteriovenous-fistula arm; document last run, access, and anticoagulants for continuous or intermittent dialysis transfers.
- Do not flood an anuric patient on a long fixed-wing leg; treat contrast and rhabdomyolysis as intrinsic hits and fly to a dialysis-capable center.
Kidneys fail in three directions, and a missed dialysis run turns all three into a cabin emergency. Domain 4.G of the August 2026 Board of Certification for Emergency Nursing (BCEN) Certified Flight Registered Nurse (CFRN) outline tests acute kidney injury (AKI) and chronic renal failure because hyperkalemia, volume overload, and a precious arteriovenous (AV) fistula do not care that you are in a King Air. Sort the type, stabilize the membrane, and fly to a machine.
Prerenal, intrinsic, and post-renal: sort before the liter
Prerenal AKI is a perfusion problem: hypovolemia, hemorrhage, over-diuresis, nonsteroidal anti-inflammatory drugs (NSAIDs), angiotensin-converting enzyme (ACE) inhibitors, or a low-output heart. Restore perfusion and the creatinine often falls. Intrinsic AKI is parenchymal damage—most often acute tubular necrosis (ATN) after ischemia or toxins, pigment injury from rhabdomyolysis, or contrast-associated AKI after a trauma computed tomography (CT) run. Post-renal AKI is obstruction: stones, clots, benign prostatic hyperplasia (BPH), or a clamped Foley catheter. One unkinked Foley has saved more flight patients than a clever pressor.
You will not have a fractional excretion of sodium in the aircraft. Use the story:
- Dry mucous membranes, flat veins, and a recent gastrointestinal loss point prerenal.
- Crush injury, dark urine, and a rising potassium point to rhabdomyolysis.
- A silent bladder or a Foley that has not drained is post-renal until proven otherwise.
Chronic kidney disease (CKD) and end-stage renal disease (ESRD) change the baseline. An anuric dialysis patient cannot make urine no matter how much crystalloid you hang. Treat them as a closed tank.
| Type | Driver | First flight move | What not to do |
|---|---|---|---|
| Prerenal | Low perfusion | Restore volume or cardiac output | NSAIDs "for the pain" |
| Intrinsic / ATN | Ischemia, contrast, pigment | Stop the toxin; treat hyperkalemia | 30 mL/kg into an anuric patient |
| Rhabdomyolysis | Myoglobin | Fluids only while urine still flows | Flood after anuria |
| Post-renal | Obstruction | Unkink or place the Foley | Climb with a clamped bag |
| Missed dialysis | Potassium, water, uremia | Calcium if the electrocardiogram is sick; fly to dialysis | A cuff on the fistula arm |
Hyperkalemia, missed dialysis, and the pericardial surprise
Membrane first, then shift, then a machine
Hyperkalemia kills by widening the QRS. Electrocardiogram (ECG) changes—peaked T waves, flattened P waves, a wide QRS, a sine wave—mean the membrane is already unstable. Give intravenous (IV) calcium (gluconate through a peripheral line, chloride if you have a central line and a crashing patient). Calcium does not lower the potassium; it buys minutes.
Then shift potassium inward:
- Insulin plus dextrose 50% (D50)—typically 10 units of regular insulin with 25 g of dextrose in an adult, watching for hypoglycemia.
- Nebulized albuterol at a high dose (often taught as 10–20 mg) if the oxygen supply allows.
- Sodium bicarbonate is situational: more useful if the patient is also profoundly acidotic, not a reflex amp.
None of those moves removes potassium. Destination is hemodialysis. Repeat the ECG after calcium. Recheck glucose after insulin.
A missed intermittent hemodialysis (IHD) run leaves potassium, extracellular water, and uremic toxins. Sit the wet patient up if the airframe allows, use noninvasive ventilation (NIV) or a higher fraction of inspired oxygen (FiO2) (Chapter 7), and do not hang a keep-open liter. A wet ESRD patient who desaturates on climb is not a Boyle's law gas problem. The lungs are already full; Dalton's law just removed the oxygen reserve. Sit them up, raise FiO2, and do not treat that desaturation with another liter. Uremic pericardial effusion can tamponade: hypotension, jugular venous distention (JVD), and a narrow pulse pressure. That is Chapter 9 obstructive shock on a renal transfer. Destination is dialysis and a window-capable intensive-care unit (ICU).
Fistula rules, CRRT handoff, contrast, and the long fixed-wing leg
The arm you do not touch
An AV fistula or graft is the patient's lifeline. Check for a thrill and a bruit, then leave that arm alone:
- No noninvasive blood-pressure (NIBP) cuff.
- No arterial line, peripheral IV, or blood draw.
- No tourniquet (TQ) on that limb if any other limb will do.
Continuous therapies, contrast hits, and anuria at altitude
Patients moving to a higher center may arrive on continuous renal replacement therapy (CRRT) or may have just finished IHD. Before you disconnect, document the last run time and net fluid removed, name the access (temporary catheter, tunneled catheter, fistula, or graft), write the anticoagulant (heparin or regional citrate) and when it stopped, and bring the last potassium, ionized calcium, and bicarbonate. Citrate plus shock plus liver failure is a hypocalcemia story.
Contrast-associated AKI after a trauma pan-scan, and pigment injury after rhabdomyolysis, are intrinsic hits. If the patient is still making urine, controlled volume and no extra nephrotoxins (NSAIDs, more contrast) is the plan. If they have become anuric, stop flooding. A long fixed-wing leg at 150 mL/h into a closed tank is pulmonary edema at cruise. Use concentrated infusions, sit the patient up if you can, and request a dialysis-ready pad.
A dialysis-dependent patient missed yesterday's run and now has peaked T waves and a widening QRS. What is the correct first sequence?
You are packaging a continuous renal-replacement patient for transfer to a higher center. The left arm has a working arteriovenous fistula. What is the correct access and handoff plan?
A crushed, now-anuric trauma patient is loaded for a three-hour fixed-wing leg after a contrast computed-tomography scan. What fluid and destination plan is most appropriate?