Intake and Output (I&O) Charting: Indications and Frequency Guidelines

When to Initiate I&O Monitoring

Start strict intake and output recording when a patient:

• Is critically ill or hemodynamically unstable.
• Receives IV fluids, vasopressors, diuretics, or blood products.
• Has fluid/electrolyte imbalances (AKI, CHF, cirrhosis, DKA, SIADH).
• Is at high risk for fluid overload or depletion (major surgery, burns, sepsis).li>
• Has renal replacement therapy (CRRT, HD).

Frequency of Measurement

• Hourly: ICU, unstable, on vasoactives, CRRT, neurosurgery.
• Every 2–4 hours: Step-down, post-op day 0–1, active fluid resuscitation.
• Every 8–12 hours: Stable floor patients with fluid restrictions/balances.
• Every 24 hours: Maintenance, low-risk (often just daily weights).

What to Record

• Intake: IV fluids (type, rate, volume), PO/NG/GT feeds, meds flushes, blood products, irrigants.
• Output: Urine (measured), stool (estimated), emesis, drains (chest, JP, penrose), fistula, insensible estimates (fever, vents).
• Balance: Running cumulative total per shift/24h.

Documentation & Communication

• Flow sheets in EMR; automated from smart pumps/scales where available.
• Shift handoff includes I&O summary, trends, concerns.
• Alert provider for: negative balance >500 mL/8h, urine output <0.5 mL/kg/h (adults), positive balance >2L/24h without explanation.