16.2 Pulmonary Embolism and Inhaled Pulmonary Vasodilators
Key Takeaways
- Massive PE is an RV afterload crisis: heparin if pressure holds, systemic thrombolysis or an EKOS/surgical-embolectomy destination if shock or arrest is present.
- Avoid high PEEP and a fluid dump; use a small fluid test only if the LV looks empty, and support RV coronary perfusion with norepinephrine.
- Inhaled nitric oxide, inhaled epoprostenol (Flolan), and conceptually inhaled milrinone unload the RV in ventilated lung and are a new 2026 CFRN topic.
- Abrupt cessation causes rebound pulmonary hypertension—tank, syringe, circuit, battery, and a bag-valve-mask without the injector all count as a stop.
- Confirm oxygen blending, analyzed FiO2, cabin leak/crew exposure, and battery versus flight time before you accept an inhaled-vasodilator transfer.
Pulmonary embolism (PE) and inhaled pulmonary vasodilators share a failing right ventricle (RV). Domain 4.C of the August 2026 Board of Certification for Emergency Nursing (BCEN) Certified Flight Registered Nurse (CFRN) outline tests PE as an obstructive-shock transfer and lists inhaled pulmonary vasodilators as a new 2026 topic.
Massive PE is an RV afterload crisis
A clot in the pulmonary arteries raises pulmonary vascular resistance (PVR). The thin-walled RV dilates, the septum bows left, the left ventricle (LV) underfills, and cardiac output falls. Hypoxia is dead space and ventilation–perfusion mismatch; hypotension is the RV dying.
Strain, heparin, lytics, and the destination
Suspect RV strain when the hypotensive, hypoxic patient has a relatively clear chest, jugular venous distention (JVD), and an electrocardiogram (ECG) with right-heart strain. Bedside ultrasound, if you have it, shows a big RV and a small LV. Troponin and B-type natriuretic peptide (BNP) rise because the RV is ischemic—do not fly a crashing PE to a clinic that can only give aspirin.
Unfractionated heparin is the usual anticoagulant bridge when blood pressure is holding. Systemic thrombolysis is the crashing, hypotensive, or arresting massive-PE move when there is no absolute bleed contraindication—follow your protocol, not a random cabin bolus. Destination matters: some patients need catheter-directed thrombolysis (often taught under the EkoSonic (EKOS) brand) or surgical embolectomy at a pulmonary-embolism-response center. Do not spend the last hour of RV life at a hospital that cannot lyse or cut.
Vent, fluids, norepinephrine, and the inhaled bridge
Avoid high positive end-expiratory pressure (PEEP). PEEP raises RV afterload. Use enough fraction of inspired oxygen (FiO2) and a modest PEEP, not an acute respiratory distress syndrome (ARDS) recruitment stack. Fluids are a small test only if the LV looks empty; a third liter over-distends the RV and empties the LV further. Norepinephrine supports RV coronary perfusion. Inhaled pulmonary vasodilators are a bridge: they drop PVR in ventilated lung units, unload the RV, and usually spare systemic mean arterial pressure (MAP) better than a systemic prostacyclin dump.
| Therapy | When it is the flight move | What it is not |
|---|---|---|
| Heparin infusion | Pressure holding, clot needs anticoagulation | A substitute for lytics in obstructive shock |
| Systemic thrombolysis | Massive PE with hypotension or arrest, no absolute contraindication | A casual bolus for every desaturation |
| EKOS / surgical embolectomy destination | Persistent shock, lytic contraindication, or a center that can extract clot | The nearest clinic with a heparin bag |
| Norepinephrine plus careful fluid | RV coronary perfusion while you fly | High PEEP plus three liters |
| Inhaled vasodilator | RV afterload bridge, pulmonary-hypertension crisis, selected ARDS hypoxemia | A drug you can just stop at the door |
Inhaled pulmonary vasodilators: new 2026 depth
These drugs are selectively delivered to ventilated alveoli. They improve matching in hypoxemic ARDS, unload a failing RV, break a pulmonary hypertension (PH) crisis, and bridge a post-cardiac surgery RV that was just weaned off bypass. They do not dissolve clot.
Inhaled nitric oxide
Inhaled nitric oxide (iNO) is a rapid, short-acting pulmonary vasodilator, typically titrated in parts per million (many programs teach a 5–20 ppm start, sometimes up to about 40 ppm). Those doses are clinical teaching, not BCEN numbers. Delivery needs a purpose-built blender (an INOmax-type device is the common hospital picture) that injects nitric oxide into the inspiratory limb, monitors nitrogen dioxide (NO2), and alarms. Watch methemoglobin. iNO is gone seconds after the injector stops, so a bag-valve-mask without the delivery limb is a sudden withdrawal. Confirm tank volume, a transport mount, and battery time before you accept the transfer.
Inhaled epoprostenol and inhaled milrinone
Inhaled epoprostenol (often still called Flolan in sending units) is a prostacyclin analog nebulized continuously into the ventilator circuit, usually with a vibrating-mesh device. It is sticky. Filters clog. The syringe or bag empties. If the nebulizer stops, rebound pulmonary hypertension can crash the RV in minutes. Inhaled milrinone is less common and is conceptual on this exam: some cardiac programs nebulize it as an RV afterload drug after cardiac surgery. Treat it like the others—know the device, the dose the sending team started, and that stopping it is a PH crisis.
Rebound, oxygen blending, cabin leak, battery
Abrupt cessation rebound PH is the flight-killer. Never let the tank, the syringe, or the battery die in cruise. Hand ventilation without the delivery device is a stop. Changing circuits without a plan is a stop. Brief the receiving team so the drug is still running at the door.
Oxygen blending matters: iNO systems mix with the set FiO2; a transport vent that cannot accept the injector changes both dose and oxygen. Confirm the analyzed FiO2, not the ventilator's hopeful number.
A closed cabin is a crew-exposure box. iNO leak and aerosolized epoprostenol are not identical to oxygen. Check circuit integrity, scavenge or exhaust per your program, and do not crack a wet circuit into the crew's faces during climb. Confirm battery time against flight time plus a diversion.
- Massive PE is RV afterload; heparin holds pressure-stable clot, lytics or an EKOS/embolectomy center treat shock.
- Avoid high PEEP and a fluid dump; use norepinephrine and a small fluid test only.
- Inhaled nitric oxide, inhaled epoprostenol, and conceptually inhaled milrinone unload the RV in ventilated lung.
- Abrupt cessation causes rebound PH—tank, syringe, circuit, and battery are part of the drug.
- Watch oxygen blending and cabin leak; these are new 2026 CFRN drugs.
A hypotensive, hypoxic patient with a dilated right ventricle, relatively clear lungs, and suspected massive pulmonary embolism is being loaded. Which plan matches RV-protective transfer?
An inhaled epoprostenol nebulizer runs dry in cruise on a patient with right-ventricular failure. What is the specific danger?
You accept a post-cardiac-surgery transfer on inhaled nitric oxide. Which device-and-cabin check is required before launch?