First five minutes
New Fever in the ICU Algorithm
Shock check, cultures, the source hunt and the mimics
1 Confirm the fever and look at the patient
- Fever is 38.3 °C (101 °F) or higher (SCCM/IDSA); with neutropenia, 38.3 °C once or 38.0 °C for an hour
- Reliable method: bladder, esophageal or PA catheter probe, then oral or rectal (no rectal if neutropenic); not axillary, tympanic or temporal
- Full vital signs, SpO₂, mental status, urine output, skin and capillary refill
- Unstable: call the rapid response team or provider now; monitor, oxygen, IV access
- Note new drugs, procedures, anesthesia, transfusions, and each line with its days in place
Blood product running or given in the last 4 hours → step 2Rigid muscles or clonus, or rising EtCO₂ and HR after anesthesia → step 3Low BP, new organ dysfunction or neutropenia → step 4Stable, no organ dysfunction → step 5
2 Fever with a transfusion: stop it
- Stop the transfusion; keep the IV open with saline through new tubing
- Vital signs; recheck the patient ID against the unit label; call the provider and the blood bank
- Return the bag and tubing; send blood for a DAT and repeat type and screen, and urine for hemoglobin
- Rigors, hypotension or a rise of 2 °C or more: blood cultures from the patient; ask the blood bank to culture the bag
- New hypoxia or pulmonary edema in the hours after: TRALI or TACO; support breathing and call now
Hypotension, rigors, back pain, dark urine or oozing → step 4Stable, fever only → step 6
3 Heat from muscle: which syndrome fits?
- Cool physically now: ice packs to neck, axillae and groin, a cooling device, cold IV fluids; antipyretics will not work
- Call the provider now; CK, potassium, creatinine and a blood gas; review every drug given in the past days
During or soon after a volatile anesthetic or succinylcholine; EtCO₂ rising → step 7Antipsychotic or metoclopramide, or stopped levodopa; rigidity over days → step 8Serotonergic drug; clonus and hyperreflexia within hours → step 9None of these fits → step 5
4 Shock, probable sepsis or neutropenia: antibiotics within 1 hour
- Call the rapid response team or provider now; time zero is recognition; follow the Sepsis: Hour-1 Bundle
- Lactate; two blood culture sets, then broad-spectrum antibiotics within 1 hour (SSC 2021)
- Hypotension or lactate 4 or more: 30 mL/kg balanced crystalloid within 3 hours, reassessing after each bolus
- MAP under 65 during or after fluids: norepinephrine; a peripheral start is fine
- Long-term steroids or adrenal insufficiency: hydrocortisone 100 mg IV for possible adrenal crisis
5 Stable, sepsis possible: rapid workup
- Tell the provider now; vital signs, mental status and urine output at least hourly
- Two or more blood culture sets from different sites, drawn back to back (ideally 60 mL of blood in all)
- Lactate, CBC, chemistry, liver tests and a chest x-ray; procalcitonin helps when infection is uncertain
- Infection still likely: antibiotics within 3 hours (SSC 2021); unlikely: hold them and keep watching
- Worse at any point (hypotension, rising lactate, new organ failure): antibiotics within 1 hour
6 Comfort and cooling
- No antipyretics just to lower the number (SCCM/IDSA 2023); in infection it did not improve survival (HEAT 2015)
- For comfort, an antipyretic is preferred over cooling blankets (SCCM/IDSA 2023)
- Acetaminophen 650–1,000 mg every 6 h, max 4 g/day (less with liver disease or alcohol use); IV doses can drop BP
- Brain injury, stroke or SAH: keep normothermic; comatose after cardiac arrest: 37.5 °C or less as ordered
- Treat fever that strains a failing heart or lungs; with a cooling device, prevent and report shivering
7 Malignant hyperthermia: dantrolene now
- Call for help, anesthesia and the MH cart; stop volatile agents and succinylcholine
- Clues: EtCO₂ rising despite more ventilation, fast HR, masseter or total rigidity, acidosis, high potassium
- 100% oxygen at 10 L/min or more; dantrolene 2.5 mg/kg IV rapidly, repeated until signs resolve
- Cool if over 39 °C and stop at 38 °C; call the MH hotline (US 1-800-644-9737)
- Follow the Malignant Hyperthermia algorithm; ICU monitoring for at least 24 hours
8 Neuroleptic malignant syndrome
- Hold the antipsychotic or metoclopramide and call the provider; restart levodopa or the dopamine agonist if it was stopped
- Clues: fever, lead-pipe rigidity, confusion, labile BP and HR, CK 4 times normal or more
- Cool physically; IV fluids to protect the kidneys; check CK, potassium and creatinine
- Benzodiazepine for agitation; severe rigidity or fever: dantrolene or bromocriptine per the provider
- ICU monitoring for airway, aspiration, arrhythmia and kidney injury; no antipsychotic until it resolves
9 Serotonin syndrome
- Hold every serotonergic drug and call the provider: SSRIs, SNRIs, MAOIs, linezolid, methylene blue, tramadol, fentanyl, ondansetron
- Clues: onset within hours; clonus (legs more than arms), hyperreflexia, tremor, agitation, sweating, diarrhea
- Benzodiazepine for agitation and tremor; avoid physical restraint, which makes more heat
- Cyproheptadine 12 mg by mouth or tube per the provider (evidence is weak); poison center 1-800-222-1222
- Over 39 °C with rigidity, agitation, falling consciousness or failed cooling: call for sedation, intubation and nondepolarizing paralysis (never succinylcholine)
10 Hunt the source, head to toe
- Lines: site redness or pus, days in place; cultures from the line (two lumens) and a vein at the same time
- Lungs: secretions, oxygen need, chest x-ray; ventilated: tracheal aspirate; viral PCR panel if respiratory signs
- Urine: culture when a urinary source is suspected; with pyuria and a catheter, replace it and culture from the new one
- Skin and gut: wounds, surgical sites, pressure injuries; C. difficile test for 3 or more loose stools in 24 h without laxatives
- Hidden: sinusitis (nasal tubes), abdomen (CT after surgery), acalculous cholecystitis (ultrasound), EVD or shunt (CSF), endocarditis
11 Report and reassess
- SBAR: temperature and how it was measured, vital signs trend, mental status, urine output, lactate
- Lines and days in place, recent procedures, transfusions, new drugs, stool count, wound changes
- What is done: culture times, first antibiotic time, fluids given, cooling started
- Ask for: the antibiotic plan, imaging of the suspected source, procalcitonin or a repeat lactate
- Recheck vital signs every 15 minutes while unstable; repeat lactate in 2–4 hours if it was over 2
12 Source found: control it
- Infected line: remove it once other access works
- Abscess, empyema, obstruction or dead tissue: surgery or IR drainage, ideally within 6 hours (SSC 2026)
- C. difficile: contact precautions, soap-and-water hand hygiene; oral vancomycin or fidaxomicin
- Antibiotics matched to the source; narrow to culture results at 48–72 hours
13 No infection found: think of the mimics
- Drug fever: beta-lactams, sulfa drugs, phenytoin, heparin; often 7–10 days in; fades within 72 h of stopping
- Clots and inflammation: DVT or PE, pancreatitis (lipase), gout, hematoma, ischemic bowel
- Adrenal crisis (shock despite fluids and pressors, low Na, high K, low glucose): hydrocortisone 100 mg IV now
- Thyroid storm, alcohol withdrawal, stimulant or anticholinergic toxicity; stroke, ICH or SAH (central fever)
- After surgery, fever in the first 48 hours is usually inflammatory; still look if the patient is unwell
Drugs in this algorithm
- Norepinephrine
- Dopamine
- Fentanyl
- Acetaminophen
- Succinylcholine
- Heparin
- Hydrocortisone
- Dantrolene
- Ondansetron
- Vancomycin
More first five minutes algorithms
Practice free in your browser2,450+ exam-style questions with rationales. No account, no ads. Also free on the App Store and Google Play.
For education and exam preparation only. Follow your institution’s protocols. Study aid with typical adult values; follow your local protocols and medical direction, and current AHA guidelines.