Читать книгу Fundamentals of Pharmacology for Paramedics - Группа авторов - Страница 38

Historically, children were considered small adults, with the same physiology and metabolic requirements as an adult, but on a smaller scale. This is now known not to be the case, but many medications are still not tested on children, so safe doses in this patient group are not established empirically. A basic understanding of the differences between adult and child anatomy and physiology will ensure safer administration of medication to children. For example, the child’s heart does not have the same capacity to raise cardiac output by increasing its force of contraction and relies on increasing the heart rate to compensate for increased demand. As a result, peripheral vasoconstriction usually occurs more readily, in order to maintain blood pressure.

Medications which cause peripheral vasoconstriction need to be used with extra caution in children because of this. Adrenaline will cause peripheral vasoconstriction when used to treat anaphylaxis or asthma, and the beta‐2 agonist salbutamol (albuterol) is also often contraindicated in children because of the possibility of tachycardia. Using medications that cause tachycardia will place further demands on a child’s heart, possibly at a time when it is already working hard to compensate. These medications have to be dosed and administered with extreme care in children, and some may be contraindicated.