# Adult abdominal / flank pain

Treat perfusion, pain, and nausea while screening for cardiac or aortic emergencies.

Population: Adult / adolescent. Scope: ALS.
Status: published. Source-linked OCEMS summary.
Summary updated: 2026-09-16.
Source checked: 2026-09-16.
Source version: See the linked OCEMS source for revision and implementation dates..
Canonical page: https://www.ocmedic.com/guides/abdominal-pain/
Official source: [SO-M-005 — Abdominal or Flank Pain, Non-Traumatic](https://www.ochealthinfo.com/sites/hca/files/import/data/files/12031.pdf)

Independent OC Medic summary. Does not replace the complete policy, current system notices, or clinical judgment.

## Key cautions & base contact

- Known or suspected pregnancy excludes the source’s ondansetron branch.
- Do not miss a cardiac or vascular cause while treating pain and vomiting.

## Source documents

- [SO-M-005 — Abdominal or Flank Pain, Non-Traumatic](https://www.ochealthinfo.com/sites/hca/files/import/data/files/12031.pdf)

## Initial assessment

- Maintain the airway and suction when needed. Assess onset, location/radiation, associated vomiting, pregnancy possibility, vital signs, and perfusion.
- Upper abdominal discomfort may be an anginal equivalent; consider a 12-lead with cardiac history or suspected cardiac origin.

## Perfusion and nausea

- For dehydration or poor perfusion with clear lungs/no CHF, give normal saline 250 mL IV and reassess; repeat to a maximum 1 L as needed for perfusion.
- For nausea/vomiting when pregnancy is neither known nor suspected, the source lists ondansetron 8 mg ODT OR 4 mg IV, with one repeat 4 mg IV dose after approximately 3 minutes for recurrent symptoms.

## Severe pain

- With systolic BP above 90, morphine is 5 mg (or 4 mg carpuject) IV/IM, with one repeat after 3 minutes as needed. Alternative fentanyl is 50 mcg IV/IM or 100 mcg IN, with one repeat after 3 minutes.
- Choose the applicable pathway, count prior doses, and reassess BP, respiratory effort, oxygenation, mental status, and pain.

## Aortic concern and destination

- Sudden abdominal/back/flank pain with shock or abnormal pulse rate can suggest AAA disruption. A pulsatile mass or lost distal pulses may be absent.
- Risk factors in the source include age above 50, male sex, hypertension, known/family AAA, or vascular disease. Contact base for suspected AAA and possible trauma-center triage.
- Otherwise transport to the nearest ERC, with ALS escort when medication or saline is given, or obtain base direction as needed.