**8. Respiratory weaning**

In case of concomitant LV insufficiency and signs of systemic hypoperfusion (with raising of

support and try to compensate the peripheral vasoconstriction with peripheral vasodilators as nitroprusside, when the MAPs allow to do that, in order to reduce left ventricle afterload and facilitate the ejection. The conditioning with inodilators as levosimendan [10] can be very helpful and, in case of massive peripheral vasodilatory response, it can be compensated with mean dosage of noradrenaline to ensure adequate MAPs. When this is not enough, an additional support with IABP should be considered, but, when insufficient, a central or peripheral VA-ECMO will be placed. The simultaneous presence of the IABP will help avoid pulmonary

**7.5. Avoid metabolic acidosis and monitor acid-base balance and kidney function**

A patient undergoing heart transplant comes from a long period of low cardiac output, so the

In the immediate postoperative period, urinary output may decrease for several reasons including intravascular volume depletion and kidney damage coming from long lasting extracorporeal support or from the use of unbalanced solutions for fluid challenge. In addition, a high use of colloidal molecules may damage directly the renal tubules with a process called "osmotic-nephrosis." If urine output is <0.5 ml/kg/h despite optimization of blood pressure, preload and CO, and use of standard diuretics (furosemide or torasemide), and the patient develops kidney failure with serum urea >200 mg/dL or hyperkalemia, kidney replacement

We prefer early application of continuous venovenous hemofiltration (CVVH) for a complete hemodynamic and fluid rebalancing. In case kidney replacement therapy is

), we will need to increase the inotrope

analogon iloprost (2 ng/kg/min)

30–35 mmHg, pH 7.5. Adequate peep level (5–10 cm H<sup>2</sup>

O)

LAP/PCWP and sudden reduction of CO, CI, and SvO2

Systemic vasodilators Sodium nitroprusside, prostacyclin PGI2

**Monitor by PAC CVP, MPAP, PCWP, CO, SvO2**

Inodilator Milrinone 0.2–0.5 mcg/kg/min

100 mmHg, pCO<sup>2</sup>

**Table 6.** Pulmonary artery hypertension monitoring and right ventricular dysfunction prevention.

to recruit lung and optimize PVR Restricted fluid therapy Monitoring filling pressure CVP 10–12 mmHg, PCWP 12–15 mmHg

Epinephrine 0.02–0.25 mcg/kg/min

maintain right coronary perfusion pressure

Monitoring LVEDV, RVEDV by echocardiography

Levosimendan 0.2 mcg/kg/min ± norepinephrine (up to 0.15 mcg/kg/min) to

Mechanical ventilation PaO2

iNO 5–40 ppm

Phosphodiesterase V inhibitor Revatio 3 × 20 mg p.o.

Inotropes to support RV

contractility

144 Heart Transplantation

edema by reducing the afterload of LV.

kidney dysfunction is often preexisting.

therapy becomes mandatory.

A patient undergoing heart transplant should remain under mechanical ventilation until hemodynamic stability is ensured, lactate levels are stable, and immunosuppressive therapy is started. To protect the lungs, we have to limit peak pressures and use low tidal volumes (6 ml/kg) with adequate PEEP level (at least 3–5 cmH<sup>2</sup> O).

However, disadvantages coming from permissive hypercapnia on the pulmonary vascular resistances and right ventricle afterload, myocardial function, and renal blood flow loads must be taken into account [16]. As a consequence, there are no universal evidences, but the choice must be tailored for the patient. The only certainty is we must avoid hypercapnia, hypoxia, and PEEP over 10 cmH<sup>2</sup> O and keep peak pressure under 35–40 cmH2 O.

During mechanical ventilation, inhaled nitric oxide can be administered in order to reduce right PA pressures, pulmonary vascular resistances, and then right ventricle afterload, especially in the first 24 hours from CPB weaning at the maximum dosage of 20–40 ppm [17, 18]. Once mechanical ventilation is discontinued, inhaled nitric oxide can be substituted by iv or oral pulmonary vasodilators as sildenafil. The weaning criteria do not differ from those used in normal cardiosurgical patients, and the goal is the same: maintain adequate analgesia and sedation levels and wean the patient from the mechanical ventilation as soon as possible. If this is not possible, due to unstable hemodynamics, high inotropic score, respiratory failure, or neurological issues, a percutaneous dilatation tracheostomy will be packaged without further delay (within the first 5–7 days of mechanical ventilation).

Once the patient is awake and self-breathing and the LAP line is removed (generally 24–48 hours from surgery), the patient will need physiotherapy and mobilization.

Early feeding is important. It is initially given via NG tube (25–30 kcal/kg/day) and then selffeeding is achieved once there is no more gastrointestinal paresis.
