Portopulmonary Hypertension (POPH)

Separate POPH from HPS first - a dyspneic cirrhotic can have either, and they pull management in opposite directions. Contrast echocardiography plus ABG identifies the HPS shunt (late bubble arrival at 4-6 cardiac cycles, PaO2 under 80 mmHg or an A-a gradient of 15 mmHg or more on room air). Right heart catheterization identifies POPH by mPAP, PVR, and LVEDP.

Right heart cath before anything big - confirmed moderate-to-severe pulmonary hypertension warrants right heart catheterization ahead of a moderate-to-high-risk procedure. Nitric oxide testing at the same sitting tells you whether the patient will respond to a pulmonary vasodilator, though 85-90% will not.

PA catheter, not just an art line - for liver transplant in POPH a pulmonary artery catheter is essential for tracking PAP and PVR, especially at reperfusion. Add an arterial line for beat-to-beat pressure and serial ABGs, and TEE for the RV — esophageal varices are a relative contraindication to the probe.

Reperfusion is the moment - graft reperfusion with excess preload can tip POPH into severe pulmonary hypertension and right heart failure. Meter the volume, watch the PA pressures, and know that venovenous bypass is one tool centers use to control preload through the anhepatic and reperfusion phases.

Hemodynamic goal - lower PVR while preserving preload and SVR. Hypoxia, hypercarbia, acidosis, hypothermia, atelectasis, and inadequate analgesia all raise PVR.

Ventilation - keep FiO2 high and PaCO2 30-35 mmHg, tidal volumes 6-8 mL/kg ideal body weight. Raise FiO2 rather than PEEP to fix oxygenation; escalating PEEP compromises preload. Avoid one-lung ventilation if there is any way around it.

Vasopressor choice - vasopressin first: systemic vasoconstriction with possible pulmonary vasodilation. Norepinephrine improves RV-to-afterload coupling through its beta-1 effect, and dobutamine improves RV function. Phenylephrine raises PVR — leave it alone.

Induction - gentle and gradual so SVR does not fall further in a circulation that is already vasodilated, but the cirrhotic with ascites is a full stomach and RSI is standard for transplant. Hold both facts and titrate rather than pick one blindly. Light laryngoscopy on a light patient produces a sympathetic surge that worsens the pulmonary pressures.

Neuraxial and blocks - spinal is avoided for the abrupt drop in preload and SVR. A gradually dosed epidural or a peripheral nerve block is a good adjunct for postoperative pain and cuts the drug load.

Small insults are not small - N2O, air bubbles in the IV line, Trendelenburg, pneumoperitoneum, and transient hypotension all matter here in a way they do not in a normal patient.

Refractory rise in PVR - inhaled pulmonary vasodilators (nitric oxide, epoprostenol). Volatile agents lower PVR; N2O and ketamine are the exceptions.

Portopulmonary hypertension (POPH) is pulmonary arterial hypertension arising in a patient with portal hypertension. Portal hypertension creates a hyperdynamic circulation — splanchnic vasodilation, low SVR, compensatory high cardiac output — and delivers vasoactive mediators to the pulmonary bed. In POPH that bed responds by vasoconstricting, so PVR climbs and the right ventricle meets an afterload it eventually cannot overcome.

This is the mirror image of hepatopulmonary syndrome (HPS), where the same portal hypertension drives pulmonary vascular dilatation, right-to-left shunt, and hypoxemia. HPS is the more common of the two, and the distinction decides everything: HPS hands you a hypoxemic patient treated with oxygen, POPH hands you a pressure-overloaded RV. Right heart catheterization settles it — mPAP at or above 25 mmHg with an elevated PVR (normal is under 3 Wood units) and LVEDP 15 mmHg or less, separating POPH from the high-flow state of cirrhosis alone.