Bladder Lavage for Hyperpyrexia

Mechanism

1. Thermal conduction — cold irrigant absorbs heat from the bladder wall and submucosal vasculature
2. Venous return cooling — cooled blood from the pelvic venous plexus returns to the central circulation
3. Core temperature reduction — repeated cycles progressively lower systemic core temperature

Clinical Context

"Cold irrigation of the bladder or gastrointestinal tract [is] less efficacious and rarely indicated."

When Bladder Lavage May Be Used

• As an adjunctive measure when other cooling methods are insufficient or unavailable
• In hyperpyrexia (core temp >41°C / 106°F), where aggressive multimodal cooling is required
• In patients where immersion or surface cooling is impractical (e.g., post-operative, ICU-bound patients)
• Alongside antipyretics; antipyretics alone are insufficient when the hypothalamic set-point is overwhelmed (e.g., heat stroke, where the thermoregulatory mechanism itself is impaired)

Limitations

• Rate of heat exchange is limited by the small surface area of the bladder mucosa compared to peritoneal or thoracic cavities
• Requires a urinary catheter (small risk of urinary tract infection with prolonged use)
• Inferior to evaporative cooling or ice-water immersion for rapid temperature reduction in heat stroke
• Not a standalone intervention — always used in combination with other cooling strategies

Bladder Lavage for Hyperthermia — Procedure

Indications

• Core temperature >41°C (106°F) not adequately controlled by first-line methods
• Used as an adjunct alongside surface cooling, evaporative cooling, or antipyretics
• Useful in ICU/post-operative patients where immersion is impractical

Equipment Required

• Foley urethral catheter (14–18 Fr) with drainage bag, or a 3-way Foley catheter (preferred — allows simultaneous irrigation and drainage)
• Normal saline (0.9% NaCl) — chilled to 4–10°C (refrigerated, not frozen)
• IV giving set or irrigation tubing
• Urometer / graduated drainage bag (to monitor output)
• Gloves, drape, antiseptic solution (for aseptic insertion)
• Thermometer for continuous core temperature monitoring (rectal or esophageal preferred)

Step-by-Step Procedure

• Use strict aseptic technique
• A 3-way (triple-lumen) Foley catheter is ideal — one lumen for balloon inflation, one for irrigation inflow, one for drainage outflow
• If only a standard 2-way catheter is available, alternating instillation and drainage cycles are performed manually

• Use chilled normal saline (0.9% NaCl) at 4–10°C
• Do not use plain water (risk of hyponatremia/hemolysis)
• Have several bags prepared; warming of the fluid during instillation is rapid

• Connect chilled saline via irrigation tubing to the irrigation port
• Instill 100–200 mL of cold saline into the bladder
• Allow a dwell time of 1–2 minutes to maximize heat exchange
• Drain fully into the collection bag
• Repeat cycles continuously until target temperature is approached

• Check core temperature every 5–10 minutes (continuous monitoring preferred)
• Target: reduce temperature to 38.5–39°C — avoid overcooling and hypothermia
• Stop or slow irrigation once the temperature reaches ~39°C

• Track irrigant input vs. urinary output carefully
• Ensure drainage is not obstructed (blocked catheter = bladder distension + discomfort)
• Watch for signs of fluid absorption, particularly in patients with bladder mucosal disruption

Key Points & Precautions

Position in Cooling Algorithm

1. Remove from hot environment / stop causative agent
2. Ice-water immersion or evaporative cooling (most effective surface methods)
3. IV cold fluids (adjunct)
4. Bladder/GI cold irrigation (adjunct when above are insufficient)
5. Peritoneal or thoracic lavage (reserved for refractory, life-threatening cases)
6. Endovascular cooling (effective but equipment-dependent)