Its ironic to believe that there are no standards set / studied or developed to diagnose pediatric hypotension. Low blood pressure in children is defined and taken as different pediatricians and hence are the maximum confusions and unnecessary use of inotropes and development of complications.
In most developing countries, low normal blood pressure is very common, its mainly related to poor nutrition including decreased intake. More so in children when any illness in children predominantly results in decreased intake and thus subclinical hypovolemia.
I had personally attended many deaths in children in intensive care settings in tertiary care settings, they aere associated mainly with hypovolemia whatever the diagnosis be.
Sometimes it was fluid restriction, sometimes inadequate correction of fluid deficit and sometimes excess diuretic administration with fluid restriction.All these surely worsen hemodynamics in
situations like nephrotic syndrome, shock sepsis, meningitis, congestive geart failure etc.
here are simple rules that help us in avoiding unnecessary use of inotropes in children especially dopamine , dobutamine and adrenaline.
following are the levels of systolic blood pressure lower normal limits below which inotrope support may be warranted provided a failur to fluid resucitation is documented with at least 60 ml/kg fluid infusion in 2 hours.
weight of child blood pressure lower normal systolic
1-2 kg 50 mm Hg
3-10 kg 60 mm Hg
10 kg and above 70 mm Hg (plus double the age in years, when age is 10 or more)
( according to standard guidelines the inotropes need to be started below 60 mmHg systolic BP in newborn, below 70mm Hg in infants and below 80 mm Hg in children upto 10 years, and above 10 years below 90 mmHg.
Most books give guidelines to maintain systolic BP to 50th centile, and give guidelines as when it drops below 50th centile, start inotropes. But this is unjustified in clinical settings when there is a significant chance of the blood pressure being normal even at 10-50th centile. So considering the normal Gaussian variation, every blood pressure cant be treated with inotropes when it starts falling below 50th centile.
Lets just give a thought, why is blood pressure needed for? to perfuse the distal most part of extremeties to maintain oxygen distribution and saturation to 96%. If the same is maintained, which can be easily assessed and monitored in children due to tehir thin skin; why is there a cry to maintain systolic BP even if saturation and perfusion is stable and normal.
Blood pressure being regulated by various mechanisms and can change with childs activity, movement of cuff tube and cuff size and also proper size BP cuffs in children is a known rarity often, its impractical to trust the readings of BP just to define hypotension. And since ist last thing to change, may be you have to wait to see the effect of ongoing therapy?
(the arguments made by many are that if BP is at 50th centile or just below it, that means body has given an indication of failing BP regulation and needs inotropes; but friends, thats not so; as if body regulatory mechanisms fail, it should immediately drop below 10th centile.
To summarise, for all practical purposes, fluid resuscitation is warranted as life saving measure, when
newborn systolic blood pressure falls below 50 mm Hg
infant systolic blood pressure falls below 60 mm Hg
and systolic child blood pressure falls below 70 mm Hg
REMEMBER DONOT THINK OF INOTROPES UNLESS YOU HAVE MADE SURE THAT BODY HAS ENOUGH BLOOD VOLUME (40-80cc per kg) IN BLOOD VESSELS, THIS CAN BE CONFIRMED BY CHECKING CVP, IT SHOULD BE MORE THAN 5 TO START INOTROPES (or at least 60-80 cc/kg fluid has to be pushed in), SO BUILD UP VENOUS VOLUME BEFORE GETTING INOTROPE SUPPORT.
Dr Kondekar Santosh venketraman is a MD pediatrician at seth GS medical college and
KEM HOSPITAL MUMBAI INDIA