Pulmonary Hypertension – ICU Management 

1. Definition 

Pulmonary Hypertension (PH)

• Mean Pulmonary Artery Pressure (mPAP) ≥ 20 mmHg at rest (Right heart catheterization)
• Pre-capillary PH:
• mPAP ≥ 20 mmHg
• PAWP ≤ 15 mmHg
• PVR ≥ 2 Wood units
• Post-capillary PH:
• PAWP > 15 mmHg

👉 ICU relevance: acute decompensated PH → right ventricular (RV) failure → shock

2. WHO Classification 

 ICU admissions most often: Group 2, 3, acute decompensation of Group 1

3. Pathophysiology (Why ICU patients crash)

Core problem

↑ PVR → ↑ RV afterload → RV dilation → RV ischemia → ↓ LV filling → shock

Vicious cycle

• RV dilation → septal shift → ↓ LV preload
• ↓ Coronary perfusion of RV
• Tricuspid regurgitation
• Systemic hypotension → further RV ischemia

 PH is primarily a RIGHT HEART disease

4. Triggers for ICU Decompensation 

• Infection / sepsis
• Hypoxia, hypercapnia
• Acidosis
• Pulmonary embolism
• Arrhythmias (AF, SVT)
• Excessive fluids
• Withdrawal of PAH drugs
• Mechanical ventilation (↑ PEEP)

5. Clinical Features in ICU

Symptoms

• Acute dyspnea
• Syncope
• Chest pain
• Fatigue

Signs

• Hypotension
• Raised JVP
• RV heave
• Loud P2
• Hepatomegaly
• Peripheral edema
• Shock with preserved lungs

6. ICU Monitoring

Essential

• Arterial line (continuous BP)
• Central venous line (CVP, ScvO₂)
• ABG (hypoxia, acidosis)
• Lactate

Advanced (selected cases)

• Echocardiography (cornerstone)
• Pulmonary artery catheter (specialist centers)

7. Echocardiography 

Key findings

• Dilated RV
• RV/LV ratio > 1
• Septal flattening (D-shaped LV)
• Reduced TAPSE (< 17 mm)
• TR jet → estimate PASP
• IVC dilated, non-collapsing

📌 Echo guides fluids, inotropes, vasopressors

8. Principles of ICU Management 

5 simultaneous goals

1. Optimize oxygenation
2. Reduce RV afterload (↓ PVR)
3. Maintain RV perfusion pressure
4. Optimize RV preload
5. Treat trigger

9. Oxygenation & Ventilation Strategy

Oxygen

• Maintain SpO₂ > 92%
• Hypoxia ↑ PVR → catastrophic

Non-invasive ventilation

• Use cautiously
• Excessive pressures worsen RV output

Intubation – VERY HIGH RISK

• Induction → hypotension
• Loss of spontaneous breathing → ↑ PVR
• ↑ Intrathoracic pressure → ↓ venous return

Intubation principles

• Experienced operator
• Avoid hypoxia, hypercapnia
• Ketamine / etomidate preferred
• Prepare vasopressors before induction

10. Mechanical Ventilation Strategy 

• Low tidal volume
• Minimal PEEP
• Avoid hypercapnia
• Avoid acidosis
• Maintain normoxia

📌 Permissive hypercapnia is DANGEROUS in PH

11. Fluid Management 

Strategy

• RV is preload-dependent but overfilling worsens RV dilation
• Aim for euvolemia
• Use echo-guided fluids

Diuretics

• IV loop diuretics if volume overloaded
• Improves RV geometry and LV filling

12. Vasopressors – Which is BEST?

Preferred agents

Norepinephrine (FIRST LINE)

• ↑ MAP → improves RV coronary perfusion
• Minimal ↑ PVR

Vasopressin (Adjunct)

• No increase in PVR
• Useful in refractory shock

Avoid

• Phenylephrine (↑ PVR)
• High-dose dopamine

📌 Goal MAP ≥ 65–70 mmHg (higher if severe RV ischemia)

13. Inotropes – RV Support

Dobutamine

• Improves RV contractility
• Risk: hypotension

Milrinone

• Inotrope + pulmonary vasodilator
• IV or inhaled
• Risk: hypotension

📌 Often NE + dobutamine/milrinone combination

14. Pulmonary Vasodilator Therapy 

Inhaled agents 

Inhaled Nitric Oxide (iNO)

• Selective pulmonary vasodilation
• Rapid effect
• No systemic hypotension

Inhaled Prostacyclins

• Epoprostenol
• Iloprost

Advantages

• ↓ PVR
• ↓ RV afterload
• Improves V/Q matching

 Inhaled > IV in unstable ICU patients

15. Continuation of Chronic PAH Therapy (VERY IMPORTANT)

!! Never abruptly stop PAH drugs

• Endothelin receptor antagonists
• PDE-5 inhibitors (sildenafil)
• Prostacyclin infusions

Stopping → rebound PH → death

16. Arrhythmia Management

• Sinus rhythm is crucial
• AF poorly tolerated
• Early cardioversion preferred
• Avoid AV nodal blockers causing hypotension

17. Thromboembolism Consideration

• Rule out acute PE
• Anticoagulation if no contraindication
• Thrombolysis in massive PE with RV failure

18. Role of Pulmonary Artery Catheter

Not routine

Useful in:

• Severe RV failure
• Refractory shock
• Transplant centers

Parameters:

• mPAP
• PAOP
• CI
• PVR
• SvO₂

19. Advanced & Rescue Therapies

ECMO

• VA-ECMO for refractory RV failure
• Bridge to recovery or transplant

Atrial septostomy

• Selected PAH cases

Lung / heart-lung transplantation

• End-stage PAH

20. Prognostic Indicators 

Poor prognosis:

• Hypotension
• Rising lactate
• Severe RV dysfunction
• Low TAPSE
• High BNP
• Need for mechanical ventilation