Call, Shifts, and the Evidence on Fatigue

What the evidence says

• Performance degrades sharply after ~16 hours continuous wakefulness.
• The 2am–6am window is the circadian nadir for vigilance — this is when sentinel events cluster.
• Recovery from a 24-hour shift requires 2–3 nights of normal sleep, not one.
• Consecutive nights of <6 hours sleep produce cognitive debt equivalent to total sleep deprivation after 2 weeks — and you don't feel it accurately.

Practical countermeasures

Before call

• Prophylactic nap (90 min covers one full sleep cycle) before a night shift — genuine performance benefit, not folklore.
• Light meal, hydrate. Avoid alcohol for 24h before call.
• Caffeine strategy: 200 mg at the start of the shift, another 200 mg at the circadian nadir. No caffeine in the last 4 hours before intended sleep.

During call

• Strategic napping when case load allows — even 20-minute naps restore vigilance.
• Bright light exposure (10,000 lux if available, otherwise the OR lights) during the nadir.
• Between cases: stand, walk, get outside if possible. Do not scroll — it doesn't recover you.

Post-call

• Do not drive if you feel impaired. Rideshare home is cheaper than a collision.
• Anchor sleep: sleep when you get home, but set a hard wake by early afternoon to preserve the night sleep.
• No critical decisions — financial, relational, clinical — in the 24 hours after call.

Red flags that you're chronically under-slept

• Falling asleep in <5 minutes (that's not “I sleep well,” that's sleep debt).
• Needing caffeine to function pre-noon.
• Irritability you can feel but not control.
• Slipping clinical performance you rationalize away.

Advocating for schedule changes

The AANA Standards for Nurse Anesthesia Practice and ASA guidance both support fatigue-mitigation structures. When proposing change to your group, bring:

• The data. Your department's call density and hours per FTE.
• The evidence. Cite AANA Position Statement 2.14 on Patient Safety: Fatigue, Sleep, and Work Schedule Effects.
• A specific proposal. E.g., post-call day protected, or a 12-hour ceiling on in-house call followed by relief.
• A business case. Retention cost, error risk, malpractice exposure.

Vague “we're tired” conversations fail. Structured proposals with comparator data from peer institutions succeed.