1. Management of acute right ventricle failure in the ICU
Dr Vincent Ioos
Medical ICU
Pakistan Institute of Medical Sciences

2. Introduction Neglected medical condition
RV connected to pulmonary circulation: low pressure system
Anatomical specificities of RV: thin wall (1/3 LV), crescent shape
RV considered a passive conduit between systemic and pulmonary circulation

3. Definition
« The clinical syndrome resulting from the inability of the right ventricle to provide adequate blood flow to the pulmonary circulation at a normal central venous filling pressure »

4. Main circumstances in ICU
Severe pulmonary embolism
ARDS
Sepsis induced RV dysfunction
Exacerbation of medical conditions leading to chronic pulmonary hypertension
Right ventricle infarction
Pericardial diseases
RV failure after cardiac surgery
After cardiac transplant

5. Context Cardiac versus pulmonary causes RV previously healthy (Acute)
Chronically impaired RV function (Acute on Chronic): RV hypertrophy / dilatation

6. Pulmonary hypertension: Venice 2003 classification
Pulmonary arterial hypertension (PAH)
Idiopathic (iPAH)
Familial (FPAH)
Associated with (APAH) : Collagen vascular disease, Congenital systemic-to-pulmonary shunts, Portal hypertension, HIV infection Drugs and toxins, …
Associated with significant venous or capillary involvement
Persistent pulmonary hypertension of the newborn
Pulmonary hypertension with left heart disease
Pulmonary hypertension associated with lung diseases and/or hypoxemia
Pulmonary hypertension due to chronic thrombotic and/or embolic disease
Miscellaneous (Sarciodosis, histiocytosis X, lymphangiomatosis, compression of pulmonary vessels)
Simmoneau G, Galiè N, Rubin LJ, et al: Clinical classification of
pulmonary hypertension. J Am Coll Cardiol 2004; 43:10S.

7. Physiology of the normal pulmonary circulation
Low pressure system: Prv (syst) = 25 mmHg / Plv (syst) = 120 mmHg
The pressure in the pulmonary system depends on cardiac ouput, resistance and compliance
The pulmonary vascular resistance has a particular dependency on alveolar oxygen tension, whereby alveolar hypoxia leads to pulmonary arterial vasoconstriction
High compliance of the pulmonary vessels with large diameter and thin wall

8. O2 requirements and blood supply to the RV
Less O2 requirements than the LV : less myocardic mass, less pre load and after load .
During stress, extraction reserve is greater.
Vascularisation : 2/3 RCA, 1/3 left branches
RV perfused in both systolic and diastolic phases as a result of the low systolic pressure (25 mmHg), which does not occlude the vessel that has a systemic pressure.
If afterload , pressure necessary to contract the RV successfully , partial occlusion of the RCA may occur  ischaemia.

9. Pathophysiology of failing RV
Piazza, G. et al. Chest 2005;128:

10. Ventricular interdependence
During systole, LV protrudes in RV
Surrounding pericardium with limited distensibility
Compliance of one ventricle can modify the other = Diastolic ventricular interaction

11. Right to left shunting Increase in RA pressure due to RVF
Reopening of patent foramen ovale
Right to left shunting
Secondary hypoxemia
Can be improved by improving RV function
Hypoxemia usually not improved by mechanical ventilation in case of RVF due to pulmonary hypertension due to pulmonary vascular disease (PAH, CTEPH)

12. Vicious cycle of auto-aggravation

13. Management Control of trigerring factors Supportive treatment:
Optimization of preload
Improving contractility
Pulmonary vasodilators
Specific therapies addressing the cause of RVF

14. Treatment of triggering factors (acute on chronic)
Arrhytmias
Infections
Pulmonary embolism
Thyroïd dysfunction

15. Optimization of preload
Frank-Starling relationship between preload and stroke volume: preload dependance (A) and preload independance (B)

16. Fluid therapy

17. Diuretics Frequent volume overload
At a point of Frank-Starling curve where there is no more reserve on contractility
Ventricular interdependance
Diuretics to be considered
Sometimes with continuous high dose infusion
If fails, consider CVVHF

18. Prospective, controlled, randomized, animal study
22 dogs underwent transient PA constriction (90mn)
Dobutamine 5 and 10 g/kg/mn, norepinephrine 0.1 to 0.5 g/kg/mn
A transient increase in PA pressure persistently worsens PA hemodynamics, RV contractility, RV-PA coupling, and cardiac output.
Dobutamine restores RV-PA coupling and cardiac output better than norepinephrine because of its more pronounced inotropic effect

19. Dobutamine 1 adrenergic stimulation  CI  PVR at 5 g/kg/mn
At higher dose  HR without subsequent  in PVR
Experimental models Dobutamine  Norepinephrine to improve right-ventricular – pulmonary artery coupling
Improves CI, PVR and PaO2/FiO2 in combination with Inhaled nitric oxyde

20. Norepinephrine 1 and 1 adrenergic stimulation Increases mPAP and PVR
But marked improvement in CO
Useful in combination with Dobutamine for hypotensive patients
Causes less tachycardia than other inotropes
Second choice after Dobutamine in normotensive patients

21. Levosimendan
Calcium sentitizer: increases the sensitivity of troponin C for Ca2+ within cardiac myocyte
Dilatation of pulmonary vasculature by activation of adenosin tri-phosphate potassium channel
Animal studies and pilot studies support its efficacy in right ventricle failure associated with pulmonary hypertension

22. Improvement of right ventricle performance:
35 ICU patients with ARDS and sepsis randomized to receive placebo or levosimendan 0.2g/kg/mn
Mean arterial pressure 80 to 90 mmHg (sustained by norepinephrine infusion)
Improvement of right ventricle performance:
CI (from 3.8 1.1 to 4.2 1.0 L/min/m2)
PAPm (from 29  3 to 25  3 mm Hg)
 RVESV, RVEF, SvO2

23. Addressing the cause of the RV failure, if possible
Treatment of Pulmonary Arterial Hypertension
Pericardiotomy/ drainage
Thrombolysis / embolectomy
Thrombolysis / angioplasty
Thromboendarteriectomy
Atrial septostomy
Transplantation

24. Pulmonary vasodilators

25. Inhaled nitric oxyde
Dilate pulmonary vessels in ventilated units of the lung
Reverses hypoxic pulmonary vasoconstriction
In acutely decompensated RV improves PVR, increase CO improve PaO2/FiO2 (Benker KA et Al. Am J Crit Care Mar;6(2):127-31)
Beware of methemoglobinemia (high concentraton, prolonged use)

26. Effect of abrupt discontinuation of NO
2002 Yearbook of Intensive Care and Emergency Medicine,
Acute right ventricular failure: physiology and therapy by Renaud E, Karpati P, Mebazaa A

27. Prostanoids Intravenous Epoprostenol
Effect on survival in stable patients with PAH
Reduces mPAP and improves CO
Systemic side effects
Worsening PaO2/FiO2
Systemic effects (hypotension)
Inhaled prostacyclin / nebulized iloprost: case series (Shock associated with PAH, Olschewski H. Intensive Care Med Jun;24(6):631-4)

28. Sidenafil Phosphodiesterase-5 inhibitor
Approved for treatment of PAH (stable patients)
Only case reports for use in critically ill (RVF after transplant: De Santo LS et Al.Transplant Proc Jul-Aug; 40(6): )
May be useful for weaning from inhaled nitric oxyde
Effect start 15mn after administration, peak effects within 30-60mn
Systemic hypotension

29. Effects of mechanical ventilation
Increased RV afterload due to positive pressure ventilation
Hemodynamic failure frequently refractory in PAH patient put on MV
In ARDS increase in mPAP while increasing tidal volume and PEEP
Permissive hypercapnia is deleterious (increase in mPAP)

30. Effect of MV on venous return

31. Effects of transpulmonary presure on RV outflow impedance

32. Effects of PEEP on RV performance

33. Effect of high PEEP on RV

34. Haddad F, MD; Circulation. 2008;117:1717-1731