1. 50-500 nanograms/kg/min (0.05-0.5 micrograms/kg/minute) by continuous IV infusion via a central venous catheter.
2. Dose is guideline only and must be considered in light of clinical response. Begin at low dose and titrate to effect. Dosages should be increased or decreased in small increments only.
3. Administer via a central line (UVC, Longline, or Surgical CVL).
4. Usual dilution 300 micrograms/kg (0.3 ml/kg) noradrenaline to make 50 ml with D5W.
   50 nanograms/kg/min (0.05 micrograms/kg/minute) = 0.5 ml/hour .

Noradrenaline (mcg) in 50ml IV Solution =

3 x weight (kg) x dose (nanograms/kg/min)                 IV Rate (ml/hr)

Indication

1. Blood pressure support in infants who are not responsive to high dose dopamine (i.e. (15-20 micrograms/kg/minute).

• Must discuss with the specialist on duty before instituting this treatment.

Contraindications

1. Uncorrected hypovolaemia is an absolute contraindication.
2. Hypertension.
3. Mesenteric or peripheral vascular thrombosis ².

Precautions

1. Hypoxia or hypercapnia (may cause noradrenaline-induced cardiac arrhythmias).

Drug Interactions

1. Halogenated anaesthetic agents: serious cardiac arrhythmias may occur with concomitant use ⁴.
2. Digoxin: increased risk of arrhythmias ⁴.
3. Beta blockers: risk of hypertension ⁴.
4. Doxapram: risk of hypertension ⁴.

Clinical Pharmacology

Noradrenaline is a catecholamine agent with β-1 and potent α-1 activity. It acts primarily to raise systemic vascular resistance and therefore blood pressure. It also has a direct stimulatory action on the myocardium. However, this may be overshadowed by reflex decreases in cardiac output occasionally manifested by a reduction in heart rate. Marked bradycardia would be unusual (adults) and indeed heart rate may increase. There is virtually no published data on the haemodynamic effects in the neonatal age group. There is no evidence of a beneficial effect on the ratio of pulmonary vascular resistance/systemic vascular resistance in persistent pulmonary hypertension of the newborn. The drug must be given by continuous infusion. It is rapidly metabolised and has a half-life of less than 5 minutes.

Possible Adverse Effects

1. Extravasation can cause profound local vasoconstriction and tissue necrosis. If extravasation occurs infiltrate with 5 mg phentolamine mesylate in 10 ml sodium chloride 0.9% using a fine neeedle ⁴.
2. May cause large increases in blood pressure. Rapid changes in blood pressure should be avoided.
3. Plasma volume depletion ⁴.
4. Arrhythmias, bradycardia. Severe arrhythmias warrant discontinuation of the drug.
5. Peripheral ischaemia including gangrene of the extremities ⁴.
6. Contains sodium metabisulphite as preservative. This agent can cause hypersensitivity reactions including anaphylactic symptoms ².

Special Considerations

1. Ensure patient is not hypovolaemic. Correct if necessary before commencing therapy.
2. Administer via a central venous catheter.
3. Clinical experience with noradrenaline is extremely limited and clinical efficacy and potential problems are not clearly defined. It is therefore not appropriate as a first line treatment and should be reserved for intractable hypotension not responsive to volume loading or high dose dopamine.
4. Safety and efficacy of noradrenaline in paediatric patients has not been established ² .