16.3 Abdominal Medical Emergencies

Abdominal medical emergencies kill by pressure, blood, or dead gut—not by a soft-abdomen story. Domain 4.D of the August 2026 Board of Certification for Emergency Nursing (BCEN) Certified Flight Registered Nurse (CFRN) outline tests abdominal compartment syndrome (ACS), gastrointestinal bleeding, and hollow- versus solid-organ medical disease as destination and altitude problems.

Abdominal compartment syndrome

Intra-abdominal pressure (IAP) is the hidden afterload on every organ you already packaged. A closed belly squeezes the kidneys, the vena cava, and the diaphragms until the ventilator looks broken and the Foley looks dry.

Bladder pressure, oliguria, high vent pressures

Measure IAP with a bladder-pressure setup when the sending team has one: a clamped Foley catheter, a pressure transducer zeroed at the iliac crest, and a small saline instill per your protocol. Those milliliters are clinical teaching, not BCEN numbers. Do the measurement on the ramp if you can; a vibrating cabin is a poor manometer. Intra-abdominal hypertension (IAH) is commonly taught as IAP at or above 12 mm Hg. ACS is IAP at or above about 20 mm Hg plus new organ failure—oliguria, high peak and plateau pressures, falling venous return, and a tight belly.

Do not fix ACS by stacking positive end-expiratory pressure (PEEP). The lungs are being squeezed from below. Sit the head up if the cabin allows, decompress the stomach with a tube, stop forcing liters into a closed belly, support mean arterial pressure (MAP) so abdominal perfusion pressure (MAP minus IAP) stays real, and fly to a surgeon who can do a decompressive laparotomy. Boyle's law expands bowel gas on climb; a tight abdomen at the pad is tighter at altitude. Request a lower cabin and treat every unexplained high-pressure alarm as belly until you have ruled it out.

Upper versus lower gastrointestinal bleed

Airway, sending meds, massive transfusion, balloon tubes

An upper gastrointestinal (GI) bleed—varices, ulcer—vomits blood and threatens the airway first. A lower GI bleed usually presents as hematochezia or maroon stool; it can still empty the tank. Sit the patient up if the spine allows, suction, and intubate on the ramp if they are vomiting blood or becoming sleepy (Chapter 7). Noninvasive ventilation (NIV) is an aspiration machine in hematemesis—do not mask a bleeder (Chapter 7). Sending meds you should recognize: a proton-pump inhibitor (PPI) infusion for ulcer disease and octreotide (or a somatostatin analog) for known or suspected varices. Those are bridge drugs, not a destination.

Massive transfusion follows the same blood-first logic as trauma (Chapter 10): blood, plasma, and platelets, ionized calcium, and a warm cabin—not three liters of crystalloid. A Sengstaken–Blakemore or similar balloon tamponade tube is not a flight souvenir. Use it only if you are trained, the airway is already secured, and the receiving endoscopist is minutes away. A migrated gastric balloon obstructs the airway. If you cannot manage that in a vibrating cabin, do not place the tube.

Hollow-organ and solid-organ medical disease

Obstruction, perforation, mesenteric ischemia

Hollow-organ medical disease is a gas-and-ischemia problem. Bowel obstruction distends loops with air and fluid. Place a nasogastric (NG) or orogastric (OG) tube and confirm suction before climb—Boyle will expand that gas whether you like it or not. Clamp the tube only if you are checking residuals per a specific protocol; a clamped tube at altitude is a Boyle bomb. Perforation is peritonitis plus free air; treat sepsis, give the sending antibiotics, and do not delay for another film at a clinic. Mesenteric ischemia is pain out of proportion to the abdominal exam, often with a rising lactate and a fibrillating atrium (Chapter 15). They need a vascular or surgical reperfusion center, not pain medicine and a hopeful cruise.

Pancreatitis, hepatic failure, varices

Solid-organ medical disease still bleeds and still swells. Pancreatitis is third-space loss, hypocalcemia, acute respiratory distress syndrome (ARDS) risk, and sometimes abdominal hypertension—resuscitate to perfusion, not to an automatic 30 mL/kg if the belly is mounting. Hepatic failure brings coagulopathy, hypoglycemia, and a brain that will herniate if sodium and ammonia run wild; keep the head up, treat hypoglycemia, and fly to a transplant-capable intensive care unit. Varices are the bleed you already packaged: octreotide, blood, airway, and an endoscopist—not a Blakemore you have never used.

• Measure bladder pressure when the belly, the urine, and the ventilator disagree; ACS is a laparotomy destination.
• Boyle expands viscera—decompress the stomach and request a lower cabin for a tight abdomen or obstruction.
• Upper GI bleed is an airway and blood problem; recognize PPI and octreotide as sending meds.
• Use a Sengstaken–Blakemore only if you are trained, the airway is secured, and destination is minutes.
• Hollow-organ obstruction needs NG/OG before altitude; mesenteric ischemia and perforation need a surgeon, not another crystalloid hour.