Table 6 Agents used to reduce PVR in the ICU setting

Intravenous

   Prostacyclin (Epoprostenol, Flolan)

Start at 1 ng/kg/min; titrate upward in 2-ng/kg/min increments according to effect

3-5 minutes (10 minutes)

Systemic hypotension, worsening oxygenation (increased V/Q mismatch), antiplatelet effect, headache, flushing, jaw pain, nausea, diarrhea

   Iloprost

1-5 ng/kg/min

30 minutes

Similar to Flolan; also syncope (5%)

   Sildenafil [325] (NB off-license use in hemodynamically unstable patients)

Low dose, 0.05 mg/kg; high dose, 0.43 mg/kg) (comes as 0.8 mg/ml)

3-5 hours

Hypotension: caution if fluid depleted, severe LV-outflow obstruction, autonomic dysfunction. Hypoxemia due to V/Q mismatch. Common: headache, flushing, diarrhea, epistaxis, tremor. Rare but important: anterior ischemic optic neuropathy

   Milrinone

50 μg/kg over 10 minutes followed by 0.375-0.75 μg/kg/min infusion

1-2 hours

Tachyarrhythmias, hypotension

   Adenosine

50-350 μg/kg/min, titrate up in 50 μg/kg/min increments

5-10 seconds (2 minutes)

Bradycardia, bronchospasm, chest pain

Inhaled (preferred; Note variable absorption likely)

   Prostacyclin (Epoprostenol, Flolan) [286, 303]

0.2-0.3 ml/min of 10-20 μg/ml nebulized into inspiratory limb of ventilator circuit (30-40 ng/kg/min)

3-5 minutes

As above but less hypotension and improved oxygenation compared with intravenous use

   Iloprost [275]

2.5-5 μg 6-9 times/day, 1 mg/ml milrinone into the ventilator circuit at 0.2-0.3 ml/min for 10-20 minutes

30 minutes

As above and bronchospasm

   Milrinone [176, 178, 179]

5-80 ppm continuously

1-2 hours

Less systemic hypotension than with IV milrinone

   NO

15-30 seconds (5 minutes)

Methemoglobinemia; withdrawal PH

ORAL (rarely in ICU)

   Bosentan

62.5-125 mg b.d.

5 hours

Liver-function test abnormalities; drug interactions; edema

   Sildenafil

0.25-0.75 mg/kg 4 hrly

3-4 hours

As above; less hypotension and hypoxemia in stable patients