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Nausea and Vomiting

Category: Medical Sources: raw/protocols/nm-sop-guidelines-treatment-2022.pdf Last updated: 2026-04-04

Overview

Nausea and vomiting are symptoms of an underlying condition, not a diagnosis. The EMT-B's job is not merely to treat the discomfort but to identify the potentially life-threatening cause. Vomiting can cause aspiration, dehydration, and electrolyte disturbances. Many serious conditions — myocardial infarction, bowel obstruction, head injury, pregnancy complications — present with nausea and vomiting as a prominent symptom.

Key Points

  • Nausea and vomiting are symptoms — always assess for the underlying cause
  • Common causes include: GI illness, cardiac (ACS), neurological (head injury, stroke, increased ICP), pregnancy, medications, metabolic derangement, bowel obstruction
  • Vomiting in an altered patient = immediate airway threat — position lateral
  • Antiemetics (Ondansetron, Promethazine) are ALS/EMT-I/P scope; EMT-B manages airway and positioning
  • Dehydration from repeated vomiting can cause hemodynamic compromise — assess volume status
  • Do not give oral medications to vomiting patients — they will not be absorbed and increase aspiration risk

Assessment Relevance

History (history-taking): - OPQRST: Onset and duration; any precipitating factors (food, medications, activity, trauma, headache); character (bile-stained, blood-tinged — "coffee grounds" suggests GI bleed); severity; associated symptoms (abdominal pain, chest pain, headache, diarrhea, fever) - SAMPLE: Last meal (content and timing); prior similar episodes; relevant medications (opioids, antibiotics, chemotherapy); pregnancy status in women of childbearing age; history of cardiac disease, kidney disease, diabetes

Physical exam (secondary-assessment): - Vital signs: hypotension + tachycardia = volume depletion or hemorrhage - Abdominal exam: tenderness, rigidity, guarding (peritonitis), distension (obstruction) - Neuro: any altered mental status, headache, neck stiffness, vision changes (CNS cause) - Skin: pallor + diaphoresis = cardiac cause; jaundice = liver disease - Signs of dehydration: dry mucous membranes, poor skin turgor, tachycardia

Red flag presentations requiring high priority: - Vomiting + chest pain or diaphoresis → possible ACS - Vomiting + severe headache or altered LOC → possible stroke or increased ICP - Vomiting + abdominal rigidity → possible surgical abdomen - Bloody or "coffee ground" emesis → possible GI hemorrhage (treat as shock) - Vomiting + pregnancy → possible ectopic pregnancy or eclampsia

Procedures

  1. Scene size-up (scene-size-up): BSI; identify MOI/NOI; look for clues (medication bottles, food containers)
  2. Primary assessment (primary-assessment): airway priority — suction immediately if vomiting; position lateral if altered LOC
  3. Secondary assessment (secondary-assessment): abdominal exam, neuro exam, vital signs
  4. Position: lateral (recovery position) if any risk of aspiration; upright if alert and no c-spine concern
  5. Airway management: suction ready at all times; have NPA/OPA available
  6. Keep NPO — nothing by mouth
  7. Transport; consider ALS intercept if hemodynamically unstable or serious underlying cause suspected
  8. IV/IO access if available and patient condition warrants (ALS scope)
  9. Reassessment (reassessment): vital signs every 5 minutes if priority patient

NM Protocol Notes

From NM EMS Treatment Guidelines (2022) — Nausea/Vomiting:

EMT-B scope: - Primary assessment — airway, breathing, circulation as indicated - Focused history for potential causes (GI, cardiovascular, gynecologic) - Consider acupressure (Pericardium-6 wrist point — non-pharmacologic option EMT-B can use) - Transport to appropriate medical facility - Normal saline bolus 500 mL (ALS); repeat as indicated; 10–20 mL/kg if pediatric (unless contraindicated — CHF, renal failure)

Anti-emetic medications (ALS/EMT-I/P scope — not EMT-B without special authorization): - ONDANSETRON (Zofran®): Adult 4 mg IV/IO/PO/IM; Pediatric 0.05–0.1 mg/kg IV/IO/PO/IM (max 4 mg) — preferred for children - PROMETHAZINE (Phenergan®): Adult 12.5–25 mg PO/IV/IO/IM

NM protocol note on dystonia/akathisia from anti-emetics — if patient develops involuntary muscle movements or restlessness after anti-emetic administration: - DIPHENHYDRAMINE: Adult 25–50 mg IV/IO/IM/PO; Pediatric 1–2 mg/kg IV/IO/IM/PO (max 50 mg)

Key NM protocol guidance: Nausea and vomiting are symptoms of illness — thorough history and physical are key to identifying what may be a disease in need of emergent treatment (bowel obstruction, MI, pregnancy).

NREMT Relevance

  • Identify life-threatening causes of nausea/vomiting — cardiac, neurological, GI hemorrhage
  • Airway is always the priority in vomiting patients — position lateral, suction ready
  • Bloody/coffee-ground emesis = GI hemorrhage = shock protocol
  • Pregnancy + vomiting = consider ectopic or eclampsia
  • Ondansetron is the preferred pediatric anti-emetic
  • Acupressure (P6 point) is a valid non-pharmacologic option at EMT-B level
  • primary-assessment — airway management; lateral positioning for vomiting patients
  • acs-chest-pain — vomiting is a common ACS associated symptom
  • stroke — vomiting with headache/AMS may indicate increased ICP
  • shock — bloody vomiting may indicate GI hemorrhage with hemodynamic compromise
  • abdominal-pain — vomiting often accompanies acute abdominal pain
  • obstetric-childbirth — hyperemesis, ectopic pregnancy, eclampsia
  • overdose-poisoning — vomiting as medication side effect or toxic ingestion symptom
  • history-taking — focused history drives the differential for cause

Sources

  • raw/protocols/nm-sop-guidelines-treatment-2022.pdf — Nausea/Vomiting protocol (p. 42)