Each of these drugs has a distinct Regorafenib effect that should be taken into account when choosing a specific therapy for each newborn (Table 2), and all of them have a significant inotropic effect. Dopamine, through its adrenergic effect, is the most effective in increasing blood pressure and therefore the most frequently used. However, there is some concern regarding a possible pulmonary vasoconstrictor effect when used at high doses. Dobutamine has an effect of reducing left ventricular overload, which together with its inotropic characteristics contribute to an increased cardiac output. Choosing the ideal vasopressor for

the treatment of newborns with hypotension remains a subject of great debate.63, 64 and 65 Attention to the cause of hypotension and myocardial performance

is of great help in therapeutic decision-making. Epinephrine, in spite of being the drug with greatest inotropic effect, also has an adrenergic vasoconstriction effect in systemic and pulmonary circulation, which sometimes leads to a significant reduction in peripheral and pulmonary blood flow. Recently, a study showed that Selleckchem Trichostatin A norepinephrine improved oxygenation and decreased pulmonary vascular resistance in newborns with PPHN through an unknown mechanism.66 In sheep, norepinephrine decreases pulmonary vascular tone and increases blood flow by activating alpha-receptors and NO release.67 and 68 In response to many vasoactive drugs, the pulmonary circulation has a similar behavior to that of systemic circulation. Thus, the great difficulty Ribonucleotide reductase in the pharmacological treatment of PPHN is to dilate the pulmonary vessels without causing systemic. As the pulmonary circulation

shows vasodilation with pH elevation, hyperventilation and alkalization have been widely used for the treatment of this disease in the past.69 and 70 Hyperventilation is no longer used due to a significant reduction in cerebral perfusion when PaCO2 is maintained < 25 mmHg, and pulmonary trauma. Alkalization, in turn, when appropriately used, has beneficial therapeutic effect with minimal side effects. This method is currently considered the standard treatment. When administered by inhalation (iNO), it reaches the alveolar space and diffuses into vascular smooth muscle of the adjacent pulmonary arteries, where it causes vasodilation by increasing cGMP levels. iNO continues to disseminate, and in the pulmonary artery lumen, it is rapidly bound to hemoglobin, restricting its effect on the pulmonary circulation, without any effect on the systemic circulation (Fig. 8). iNO is preferably distributed to the ventilated segments of the lungs, with increased perfusion in those areas. This results in an improved ventilation/perfusion ratio, decreasing intra-alveolar shunting and improving oxygenation. When the response is positive, improved oxygenation is evident within a few minutes.