Postoperative pulmonary hypertension

POSTO

PERAT

IVE

PULM

ONARY

HYPERT

ENSION

IN C

ARDIAC S

URGERY

PATI

ENTS

BY- D

R. ARM

AAN SIN

GH

BY- D

R. ARM

AAN SIN

GH

GUIDELINES FOR MANAGEMENT OF PULMONARY HYPERTENSION IN CARDIAC SURGERY PATIENTS

Increased PVR during postop period:

• SIRS 20 to CPBP (pulmonary vasoconstriction)

• Protamine (pulmonary vasoconstriction)

• Hypoxia (pulmonary vasoconstriction)

• ↑ pCO2, acidemia (pulmonary vasoconstriction)

• PEEP, ventilator dysynchrony (pulmonary vasoconstriction)

Sidebotham D, et al: Cardiothoracic critical care. Butterworth-Heinemann, Philadelphia 2007;24:374-382.



Pulmonary vasoconstriction:

• Hyperventilation counteracts hypoxic pulmonary vasoconstriction in man

• PAP increased (p < 0.001) with elevations in PaCO2

• Marked decrease in SVR with increasing PaCO2

• Blood pressure decreased (p < 0.001) with ↑ in PaCO2 up to 50 mmHg

Bindslev L, et al. Hypoxic pulmonary vasoconstriction in man: effects of hyperventilation. Acta Anesthesiol Scand. 1985;29:547-551.

Avidan MS, et al. Mild hypercapnia after uncomplicated heart surgery is not associated with hemodynamic compromise. J Cardiothorac Vasc Anesth 2007;21:371-374.

GUIDELINES FOR MANAGEMENT OF PULMONARY HYPERTENSIONIN CARDIAC SURGERY PATIENTS

Pulmonary vasoconstriction:

• Can precipitate acute right heart failure

• More frequent conditions: MVR, CHD with L → R shunt

• Heart Tx, Lung Tx

• Pneumonectomy


GUIDELINES FOR MANAGEMENT OF PULMONARY HYPERTENSIONIN CARDIAC SURGERY PATIENTS

Treatment of the underlying cause:

• Pulmonary vasoconstriction (pre-capillary PH) Avoidance of hypoxemia, hypercarbia & acidosis Sedation, analgesia & muscle relaxants Selective pulmonary vasodilatation

• Passive pulmonary hypertension with ↑ LAP (post-capillary PH) Improve LV contractility Decrease degree of MR Nesiritide


MANAGEMENT OF LEFT HEART FAILURE WITH SECONDARY PULMONARY HYPERTENSION

IN CARDIAC SURGERY PATIENTS

Nesiritide :

Perioperative management of patients with severe MR, severe LV dysfunction and secondary pulmonary hypertension

Expected mortality by EuroSCORE 26% Preoperative treatment with Nesiritide for 13-55 hr (mean=24 hr) Postoperative treatment with Nesiritide for 2-80 hr (mean=22 hr) Improves postop renal function and survival

Salzberg SP, et al: High-Risk mitral valve surgery. Perioperative hemodynamic optimization with Nesiritide (BNP). Ann Thorac Surg 2005;80:502-506.



Nesiritide :

Salzberg SP, et al: High-Risk mitral valve surgery. Perioperative hemodynamic optimization with Nesiritide (BNP). Ann Thorac Surg 2005;80:502-506.



Nesiritide:

Hemodynamic benefits: ↓ PAP, ↓ CVP, ↑ CO Improves postop renal function Decreases respiratory failure and AF Decreases LOS Decreases mortality

Blais DM. Nesiritide Compared with Milrinone for Cardiac Surgery. Ann Pharmacother 2007;41:502-504. Mentzer RM, et al: Effects of Perioperative Nesiritide in Patients With Left Ventricular Dysfunction Undergoing Cardiac Surgery. The NAPA Trial. J Am Coll Cardiol 2007;49:716-726.



Nesiritide (Natrecor):

• Standard Dilution:

[1.5 mg] [250 ml D5W, D5½S or NS]

• Loading dose:

2 mcg/kg over 20 min

• Followed by 0.01 mcg/kg/min

• Continuous infusion x 48 hours


Selective pulmonary vasodilatation:

• Right heart failure resistant to therapy

• Pre-existing pulmonary hypertension

* Inhaled Nitric Oxide (iNO)

* Inhaled Prostacyclin (iPGI2)

* Inhaled Iloprost

* Sildenafil



Inhaled Nitric Oxide (iNO):

• Usual dose: 5 - 40 ppm • Selective pulmonary vasodilator • Does not cause systemic hypotension • Distributed only to ventilated portions of the lungs • Requires accurate gas delivery system to monitor NO and NO2 • May cause methemoglobinemia • May cause rebound pulmonary hypertension • Expensive



Inhaled prostacyclin (iPGI2):

• Usual dose: 5 - 50 ng/kg/min • Short-acting selective pulmonary vasodilator • Equally effective as iNO • Does not cause systemic hypotension • Distributed only to ventilated portions of the lungs • May cause thrombocytopenia • Does not cause rebound pulmonary hypertension • Inexpensive




• Usual starting dose: 50 ng/kg/min • Weaning (3-4 days): 25-10-5-3 ng/kg/min • Selective pulmonary vasodilator • Does not cause systemic hypotension • Equally effective as iNO • Prolonged use is not associated with systemic effects • Readily available in most hospitals • Inexpensive

Lowson SM, et al: Inhaled prostacyclin for the treatment of pulmonary hypertension after cardiac surgery. Crit Care Med 2002; 30:2762-2764.


Selective pulmonary vasodilatation:

n= dobut norepi reop intub mort

IV dilators 18 4.1 0.03 2 31 2

iNO group 21 2.9 0 0 20 1

iPGI2 group 19 3.1 0 1 18 0

Fattouch K, et al: Treatment of pulmonary hypertension in patients undergoing cardiac surgery with cardiopulmonary bypass: a randomized, prospective, double-blind study. J Cardiovasc Med 2006; 7:119-123.



• Equally effective as iNO

• Neither iPGI2 nor its metabolites have toxic effects

• Possible thrombocytopenia but does not increase risk of bleeding

• Easy administration

• Inexpensive

Fattouch K, et al: Treatment of pulmonary hypertension in patients undergoing cardiac surgery with cardiopulmonary bypass: a randomized, prospective, double-blind study. J Cardiovasc Med 2006; 7:119-123.


Inhaled iloprost:

• Usual dose: 12 - 20 mcg q 4-6 hr

• Intermittent nebulization

• Longer half-life selective pulmonary vasodilator


• Does not cause systemic hypotension

• May cause thrombocytopenia

• Does not cause rebound pulmonary hypertension

• Intermittent nebulization requires periodic interruption of PEEP



Inhaled iloprost:

Rex S, et al: Inhaled iloprost to control pulmonary artery hypertension in patients undergoing mitral valve surgery: a prospective, randomized-controlled trial. Acta Anaesthesiol Scand 2008; 52: 65-72.


Sildenafil:


• Increases cardiac output

• Does not increase wedge pressure

• Oral or IV administration

• Inexpensive

Michelakis E, et al: Oral Sildenafil is an effective and specific pulmonary vasodilator in patients with pulmonary arterial hypertension. Comparison with inhaled nitric oxide. Circulation 2002;105:2398-2403.


Sildenafil:

Michelakis E, et al: Oral Sildenafil is an effective and specific pulmonary vasodilator in patients with pulmonary arterial hypertension. Comparison with inhaled nitric oxide. Circulation 2002;105:2398-2403.


Sildenafil:

Namachivayam P, et al. Sildenafil prevents rebound pulmonary hypertension after withdrawal of nitric oxide in children. Am J Respir Crit Care 2006;174:1042-1047.


Sildenafil:

• Initial dose: 50-75 mg PO 10-30 min before induction of anesthesia

• Maintenance dose: 25 mg BID - 50 mg TID

• Pediatric dose: 0.4 mg/kg before discontinuing iNO

Shim JK, et al. Effect of oral sildenafil citrate on intraoperative hemodynamics in patients with pulmonary hypertension undergoing valvular heart surgery. J Thorac Cardiovasc Surg 2006;132:1420-1425.

Trachte AL, et al: Oral sildenafil reduces pulmonary hypertension after cardiac surgery. Ann Thorac Surg 2005;79:194-197.

Health & Medicine

Postoperative pulmonary hypertension