Paediatrics: Cardiovascular system difficulty: therapy - 1

Cardiovascular system difficulty: therapy - 1

Shock

Initial therapy includes the following.

·  Oxygen: provide supplemental oxygen, FiO₂ 100%. Intubate if required.

·  Position: in shock, elevate the legs to improve venous return. In congestive heart failure elevate the head.

·  IV access: central access may be required, particularly when using inotropes.

·  Temperature: control fever with antipyretics (paracetamol 15mg/kg).

·  Metabolic state: correct hypoglycaemia and hypocalcaemia. Acidosis of respiratory cause should be controlled with ventilation.

Fluid volumes for shock

·  Hypovolaemia: IV 20mL/kg of normal saline. In severe volume depletion give 40–60mL/kg of normal saline, with additional increments of 10mL/kg to restore volume if small heart size on CXR, and CVP <5–10mmHg.

·  Stop resuscitation with volume:

when clinical improvement is achieved;

when clinical signs of improvement fail to appear;

if there are signs of volume overload: hepatosplenomegaly, JVP distension, gallop rhythm, wheeze and crackles.

 Inotropes for shock

·  Start inotropes:

when circulation remains unsatisfactory and CXR shows large heart, pulmonary vascular congestion, pulmonary oedema, or pleural effusion;

when CVP >10–15mmHg; once initiated, titrate dose upward to produce the effect required.

·  Hypotension with tachycardia:

dopamine—1–20microgram/kg/min (start at 5microgram/kg/min).

dobutamine—2–20microgram/kg/min (start at 5microgram/kg/min). Can use peripheral IV.

Dysrhythmias

Sinus bradycardia and heart block

·  Do not treat if haemodynamically stable (i.e. BP and perfusion).

·  Consider other treatable causes of bradycardia, such as raised ICP, acidosis, or hypercapnia.

·  Atropine: 0.02mg/kg IV (min 0.1mg; max 1mg).

Intensive care treatments for shock

Hypotension with normal or low HR

·   Adrenaline: 0.05–1microgram/kg/min (start at 0.05–0.10 microgram/ kg/min)

·   Noradrenaline: 0.05–1microgram/kg/min (start at 0.05–0.10 microgram/kg/min)

·   Amrinone: load 0.75mg/kg IV over 3min, then give 5–10microgram/ kg/min

Hypotension refractory to volume and single inotrope

·   Seek intensive care advice as these patients will usually need intubation and ventilation, and steroids

·   Combinations of inotropes are used in this instance

·   Afterload reduction may be required with sodium nitroprusside: 0.5–7micrograms/kg/min (start 0.5microgram/kg/min)

Diuresis for volume overload

·   Start diuretics: after circulation is restored expected urine volume is 1mL/kg/hr

·   If oliguria or anuria use furosemide 0.5–1mg/kg IV or mannitol 0.5–1g/kg IV

Tachydysrhythmia—SVT

Treatment will require consultation with a cardiac specialist. If haemody-namically stable, consider the following:

·Vagal manoeuvres: ice bag to face for 15–20s or unilateral carotid massage or Valsalva manoeuvre. Do not compress orbits.

·Adenosine: 50–100micrograms/kg initially, as rapid IV push.

·DC shock: synchronized countershock 1J/kg should be reserved for the haemodynamically unstable. Intubation and appropriate analgesia and sedation are required.

·Other drugs: amiodarone, procainamide, flecainide.

Ventricular tachycardia

If haemodynamically stable and pulse, consider the following after advice from cardiac specialist:

·If pulse present: amiodarone 5mg/kg; synchronized shock.

·  Pulseless.