4 *MYTHS* about Newborn Blood Pressure!! And why they're WRONG!!

Summary

Dr. Tala, a neonatologist with 16 years of experience, discusses neonatal hypotension in a series of videos. She addresses common myths around blood pressure management in NICUs, focusing on the distinctions between vasopressors, inotropes, and chronotropic drugs. Dr. Tala emphasizes the importance of selecting the correct medication based on the underlying cause of low blood pressure, rather than using terms interchangeably. She also debunks the idea that blood pressure alone is a reliable indicator of neonatal oxygenation, advocating for a more comprehensive approach to evaluating and treating neonatal hypotension.

Takeaways

• 📉 Low blood pressure in neonates is not universally treated the same way across cases, and treatment should depend on the specific cause.
• 💊 Vasopressors and inotropes are different: vasopressors increase diastolic pressure by squeezing blood vessels, while inotropes enhance the heart's contractility, increasing systolic pressure.
• ⏱ Chronotropic drugs, such as epinephrine and dobutamine, increase the heart rate (chronotropy), while some drugs can have multiple effects depending on dosage.
• 👶 Neonatal blood pressure is a poor indicator of blood flow, especially within the first 24 hours of life; other markers like urine output, capillary refill, and lactic acid levels offer more insights.
• 🫀 Blood pressure is only a surrogate marker for blood flow and oxygenation. Even if blood pressure seems normal, there may still be insufficient blood flow to the body's tissues.
• 🧪 When assessing low blood flow, check for signs such as pale skin, delayed capillary refill, decreased urine output, and elevated lactic acid.
• 📏 The mean blood pressure, while commonly used, may not fully indicate adequate perfusion; assessing systolic and diastolic values can provide more clarity, especially in cases like PDA (Patent Ductus Arteriosus).
• 📊 Studies show only a weak correlation between low blood pressure treatment and improved neonatal outcomes, and not all cases of hypotension require intervention.
• 🧠 Treating low blood pressure alone doesn’t necessarily improve outcomes; it’s more effective to intervene when there are signs of inadequate oxygenation, such as high lactic acid levels.
• 📚 It’s critical to match the right medication to the cause of the hypotension—whether vasopressors or inotropes—rather than assuming a one-size-fits-all approach.

Q & A

What is considered a low blood pressure in neonates, and when should it be treated?

A low blood pressure in neonates varies depending on gestational age, clinical condition, and other factors. It is not defined by a single number but rather by a combination of clinical signs and measurements. Treatment should be considered if there are signs of poor perfusion, such as pallor, delayed capillary refill, low urine output, or increased lactate levels, rather than just based on blood pressure alone.

What is the difference between inotropes and vasopressors?

Inotropes are medications that increase the contractility of the heart, making it squeeze harder (e.g., epinephrine, dobutamine, milrinone). They generally increase systolic blood pressure. Vasopressors, on the other hand, work by constricting peripheral blood vessels, increasing diastolic blood pressure (e.g., norepinephrine, vasopressin, dopamine at higher doses). The two should not be used interchangeably as they have different effects.

Why is it important to choose the right medication for hypotension in neonates?

Choosing the right medication is crucial because different types of hypotension may require different treatments. For example, a baby with septic shock and dilated blood vessels may benefit more from a vasopressor to increase diastolic blood pressure, while a baby with poor heart contractility would need an inotrope to improve systolic blood pressure. Using the wrong medication could exacerbate the condition.

Why might mean blood pressure not be the best indicator of a neonate's overall status?

Mean blood pressure is just an average of systolic and diastolic pressures and does not give a complete picture of the baby’s perfusion status. A normal mean blood pressure can mask issues like a low systolic pressure, indicating poor cardiac output, or a low diastolic pressure, indicating peripheral vasodilation. It’s essential to consider systolic and diastolic pressures separately, along with other clinical signs.

What are some clinical signs that indicate poor perfusion in a neonate?

Signs of poor perfusion include pallor, delayed capillary refill (longer than 3-4 seconds), decreased urine output (less than 1 ml/kg/hr or a significant drop from the baseline), and increased lactate levels indicating anaerobic metabolism. These signs suggest that the blood is not reaching all the cells adequately.

What does a widened pulse pressure in a neonate indicate?

A widened pulse pressure, where the difference between systolic and diastolic pressures is large, could indicate conditions such as a patent ductus arteriosus (PDA). In this situation, there may be adequate left ventricular function, but significant blood shunting during diastole, leading to decreased blood flow to the rest of the body despite a seemingly normal mean blood pressure.

How should we interpret a narrow pulse pressure in a neonate?

A narrow pulse pressure, where systolic and diastolic pressures are close together, suggests that the heart is struggling to pump effectively against a higher afterload. This may indicate conditions like cardiac dysfunction or increased systemic vascular resistance, where the heart cannot generate sufficient cardiac output.

Does treating low blood pressure in neonates improve outcomes?

Treating low blood pressure based solely on the number may not necessarily improve outcomes. Studies have shown that there is a weak correlation between blood pressure and actual perfusion, especially in the first 24 hours. Treatment should be targeted based on signs of poor perfusion and oxygen delivery to tissues, such as high lactate levels, rather than just blood pressure alone.

What was the primary outcome of the HIP trial on treating low blood pressure in preterm infants?

The HIP trial found that infants treated with dopamine had slightly higher blood pressures, but there was no significant difference in the primary outcome of survival without severe brain injury compared to those who received a placebo. This suggests that treating low blood pressure with dopamine alone may not necessarily improve outcomes and highlights the need for individualized treatment approaches.

What are other indicators besides blood pressure that clinicians should consider when assessing neonatal perfusion and oxygenation status?

Clinicians should consider signs such as pallor, delayed capillary refill, decreased urine output, and increased lactate levels. These indicate poor perfusion and inadequate oxygen delivery to tissues. Additionally, monitoring for metabolic acidosis can provide clues about the baby’s oxygenation and perfusion status beyond just blood pressure readings.

Outlines

00:00

🩺 Understanding Neonatal Hypotension: A New Approach

This paragraph introduces the main topic: hypotension in neonates. Dr. Tala, a neonatologist with 16 years of experience, shares insights on how to define low blood pressure in newborns and discusses the approach to treatment. She highlights that neonatal blood pressure management has evolved, with the realization that different babies may require different treatments depending on their condition. She emphasizes that blood pressure medications like vasopressors and inotropes are not interchangeable and should be used based on the baby's specific needs. The paragraph sets the stage for a discussion of neonatal hypotension myths and best practices.

05:03

💉 Myth 1: Vasopressors and Inotropes Are Not the Same

In this section, Dr. Tala debunks the myth that vasopressors and inotropes can be used interchangeably. She explains that while inotropes increase the heart's contractility, vasopressors work by constricting blood vessels to raise blood pressure. The key distinction is that inotropes like epinephrine and dobutamine target systolic pressure, while vasopressors such as norepinephrine and vasopressin influence diastolic pressure. She also introduces chronotropic drugs that affect heart rate. The paragraph stresses the importance of choosing the right medication based on the baby's condition and not treating all low blood pressures the same way.

10:05

📊 Myth 2: Blood Pressure Is Not Always a Good Indicator of Oxygenation

Dr. Tala addresses the misconception that blood pressure alone can reliably indicate a baby's oxygenation status. She explains that adequate oxygen delivery to the cells depends not only on blood pressure but also on factors like cardiac output and oxygen content in the blood. In some cases, a baby might have normal blood pressure but still suffer from poor oxygenation due to issues like anemia or respiratory distress. She highlights that a comprehensive assessment should include other markers of blood flow, such as skin perfusion, urine output, and lactic acid levels, to get a more accurate picture of the baby's oxygenation.

15:06

🩸 Myth 3: Mean Blood Pressure Isn’t the Full Picture

Here, Dr. Tala challenges the common practice of relying heavily on mean blood pressure as a measure of neonatal health. While mean blood pressure can provide useful information, it doesn’t tell the whole story. She explains that in neonates, systolic and diastolic blood pressure also provide important clues about heart function and blood flow. For instance, a widened pulse pressure can indicate conditions like patent ductus arteriosus (PDA), where blood might not be reaching the body despite an acceptable mean pressure. She stresses the importance of considering all components of blood pressure rather than just focusing on the mean.

20:08

🔍 Myth 4: Treating Low Blood Pressure Always Improves Outcomes

Dr. Tala tackles the belief that treating low blood pressure in neonates will automatically lead to better outcomes. She discusses research, particularly the HIP trial, which tested the effect of treating low blood pressure with dopamine in premature babies. The study showed that while dopamine raised blood pressure, it didn’t necessarily lead to better outcomes in terms of survival without brain injury. However, the study was underpowered, meaning more research is needed. The key takeaway is that treatment should focus on improving blood flow and oxygen delivery, not just raising blood pressure.

Keywords

💡Hypotension

Hypotension refers to low blood pressure, which is a central focus of this video. In neonates, particularly in the NICU, managing hypotension is critical as it can be an indicator of insufficient blood flow to vital organs. The video discusses when hypotension should be treated and what medications should be used, highlighting the complexity of treating low blood pressure in different scenarios.

💡Inotropes

Inotropes are drugs that increase the contractility of the heart, making it pump more effectively. These medications, like epinephrine and dobutamine, are used to manage systolic blood pressure. The video stresses the importance of using inotropes in specific situations, like when a neonate's heart is not pumping adequately, rather than using them interchangeably with other drug classes like vasopressors.

💡Vasopressors

Vasopressors are medications that cause the blood vessels to constrict, increasing diastolic blood pressure. Examples include norepinephrine and vasopressin. The video explains the distinction between vasopressors and inotropes, emphasizing that different medications should be used based on the specific causes of low blood pressure, such as septic shock in neonates where vasopressors are needed to improve circulation.

💡Chronotropes

Chronotropes are drugs that increase the heart rate. The video provides examples like epinephrine, which not only increases heart rate but also has inotropic effects, improving heart contractility. Chronotropes are often used during resuscitation efforts in neonates to ensure adequate heart rate and circulation, especially during emergencies like delivery room resuscitations.

💡Cardiac Output

Cardiac output refers to the amount of blood the heart pumps in a given time. It's a crucial factor in ensuring adequate blood flow and oxygen delivery to the cells. The video highlights that cardiac output must be sufficient for the neonate's organs to receive enough oxygen, which is why monitoring and managing blood pressure is so important, but it alone isn't always an accurate indicator of sufficient cardiac output.

💡Mean Blood Pressure

Mean blood pressure is the average of systolic and diastolic blood pressure values. In neonates, the video explains that mean blood pressure can be used as a quick reference for assessing a baby’s condition, particularly in premature infants, where it should approximate the gestational age in weeks. However, it’s not the most accurate measure for determining overall health, and attention should be given to both systolic and diastolic pressures as well.

💡Pulse Pressure

Pulse pressure is the difference between systolic and diastolic blood pressure. The video explains that a widened pulse pressure may indicate conditions like patent ductus arteriosus (PDA), where blood isn't adequately circulated despite a normal mean blood pressure. It's a useful indicator when assessing whether neonates are receiving enough blood flow to their tissues.

💡Lactic Acidosis

Lactic acidosis occurs when cells are not receiving enough oxygen, causing them to produce lactic acid through anaerobic metabolism. In the video, the rise in lactic acid is used as an indicator that the baby’s tissues are not receiving sufficient oxygen, despite what might appear to be an adequate blood pressure. This is crucial in deciding whether to treat low blood pressure.

💡Perfusion

Perfusion refers to the flow of blood to tissues and organs, ensuring they receive oxygen and nutrients. The video emphasizes that adequate perfusion is essential for cellular metabolism. Neonates with poor perfusion might show signs like pale skin, poor capillary refill, or reduced urine output, indicating that blood flow is insufficient even if blood pressure seems normal.

💡Vasoactive Agents

Vasoactive agents are medications that affect blood pressure by altering the tone of blood vessels or heart function. These include inotropes, vasopressors, and chronotropes. The video addresses the myth that all these drugs can be used interchangeably, explaining that they have different mechanisms and should be selected based on the underlying cause of the neonate's hypotension.

Highlights

Introduction by Dr. Tala, a neonatologist with 16 years of experience, discussing hypotension in neonates and blood pressure management in NICU.

Dr. Tala points out the misconception that vasopressors and inotropes are interchangeable and emphasizes that they work differently.

Inotropes increase heart contractility, while vasopressors constrict peripheral blood vessels, impacting diastolic blood pressure.

Epinephrine serves as both a chronotrope, increasing heart rate, and an inotrope, improving heart contraction.

Dopamine affects different receptors based on dosage, illustrating how medication effects vary with dose adjustments.

The importance of identifying the cause of hypotension to choose the right treatment: for sepsis, vasopressors are needed; for heart issues, inotropes are more appropriate.

Myth 1 debunked: Vasoactive agents affect neonatal blood pressure but come from different drug classes, including inotropes, vasopressors, and chronotropes.

Myth 2 debunked: Blood pressure alone is not a reliable indicator of neonatal oxygenation status; other factors like skin pallor, capillary refill, and lactic acidosis should be considered.

Myth 3 debunked: The mean blood pressure is not the most critical indicator of a baby's condition; both systolic and diastolic pressures provide additional insights.

The 'rule of thumb' for mean blood pressure is that it should be around the baby's gestational age, but this doesn't always reflect adequate blood flow.

Examples showing how narrow or wide pulse pressures can indicate underlying issues like PDA, even when the mean blood pressure appears normal.

Myth 4 debunked: Routinely treating low blood pressures in neonates doesn’t always improve outcomes; addressing the root cause is more crucial.

Study discussed: The HIP trial showed that dopamine raised blood pressure but did not significantly improve survival rates or brain injury outcomes.

Difficulties in determining the true effectiveness of blood pressure treatments due to study limitations and crossover between treatment groups.

Conclusion of the video: Treating blood pressure alone isn't enough to improve neonatal outcomes; clinicians should focus on whether the baby is receiving adequate oxygen at the cellular level.

Transcripts

what is considered a low blood pressure

in a neonate when should we be treating

those low blood pressures and how should

we be treating those low blood pressures

which medications should we be choosing

hi I'm Dr tala and I've been a

neonatologist for about 16 years now I'm

also post call today so bear with me a

little bit but for the next three videos

we're going to be discussing blood

pressures or more specifically

hypotension in the neck Cube there are

so many questions about Neon

hypertension and in the next couple of

videos we're going to go over the myths

that we all kind of perpetrate in the

niku in part three of this series we're

going to be discussing different

clinical approaches to different types

of hypertension if you will before I go

on I just want to say I used so many

resources for these videos but I kept

coming back to these two papers by Dr

Ginger and Dr malali I've put the

references below they are excellent

review articles on neonatal hypertension

let's get started with myth number one

so the first myth is that we can use the

terms vasopress and inotropes

interchangeably because they basically

mean the same thing okay I'm starting

here because it really sums up how we've

been treating blood pressure management

up until recently that a low blood

pressure in one baby is the same thing

as a low blood pressure on another baby

and we should give them the same

medication and so we might as well call

all the medications the same thing and

we'll talk about this a lot more in the

coming two videos but we're realizing

that really none of that is true and all

these different blood pressure

medications if you will work in a

slightly different way so ideally we

need to pick exactly the right

medication for a specific scenario so a

lot of the time when we're using the

terms vasopress and inotropes

interchangeably then we're just flat out

wrong they don't work the same way and

it also kind of glosses over that we

don't really understand what's going on

with the baby if we're using these terms

in the same way so let's go over these

definitions an inotrope is a medication

that causes the heart to squeeze harder

or it increases the contractility of the

heart remember this by thinking

inotropes make the heart go in and out

in and out inotrope in and out help me

anyway these are medications like

epinephrine dobutamine and meanone and

they will all generally cause an

increase in systolic blood pressure

vasopressors on the other hand are

medications that will squeeze the

peripheral blood vessels so literally

Vaso vessel presser squeeze and these

are medications like norepinephrine

vasopressin and dopamine generally these

medication because they're squeezing the

arterials and the blood vessels in the

periphery are causing an increase in

diastolic blood pressure another

definition that we use is chronotropic

drugs so chronotropic Chrono think like

a watch makes the heart rate go faster

so think what medication are we for

example using in the delivery room in a

code to try to make the heart rate go

faster yep epinephrine so epinephrine is

also Al a chronotropic drug as is for

example dobutamine it will make the

heart beat faster two important things

here that I'm sure you figured out

already and that is that each individual

drug may have more than one effect for

example epinephrine is both a

chronotrope so makes the heartbeat

faster and an inotrope so makes the

heart squeeze harder as well and it's

also possible that depending on the dose

of the drug being given then we're more

likely to see one effect over the other

so for example with dopamine which

everybody's used we use it at different

Doses and like you all know at different

doses we expect it to be hitting more of

one type of receptor so we kind of

expect it to be having slightly

different effects depending on the

dosage and we'll be talking about that a

lot more and the second thing is and

this is like really the Crux of these

whole videos is that we should be really

figuring out why the baby has a low

blood pressure and then treating with

the right medication for example if a

baby is septic and all the peripheral

vessels are all dilated and the

diastolic blood pressure is low then we

want to give a vasopressor to squeeze

those vessels and increase the diastolic

blood pressure or for example the baby

had hiie and the Heart took a hit as

well and is not squeezing well then in

this scenario what do we want we

definitely don't want a vasopressor that

will make the heart having to work even

harder against the increased pressures

in this scenario we would want an

inotrope so that it will squeeze the

heart better so to rewrite myth number

one vasoactive agents are medications

that affect a baby's blood pressure and

they include different classes of drugs

including inotropes vasopressins

chronotropes myth number two a blood

pressure is a good indicator of the

baby's oxy ation status we can really

get to the heart of this why do we care

about a good blood pressure at all well

this is a question that we can answer we

care about a blood pressure because

we're hoping that it will indicate

adequate blood flu to make sure that all

the cells in the body are getting the

oxygen that they need or another more

scientific way of saying it we need

adequate blood flow to make sure that we

are getting end organ profusion and

maintaining cellular metabolism so if

the heart isn't pumping hard enough or

there's another reason why the blood

isn't reaching all the cells in the body

then we're going to have a problem the

babies also don't get the oxygen they

need if there literally isn't enough

oxygen in the blood so even if the heart

is pumping really well and the blood

pressure is fine but for example the

baby is really anemic and isn't carrying

enough oxygen or for example the baby

has horrible pulmonary hyp potential or

respiratory distress and the baby's sats

are in the 50s and the blood just isn't

carrying any Oxygen then again those

cells aren't going to get the oxygen

that they need so basically to make sure

that the cells all the cells in the body

are receiving the oxygen they need for

their cellular metabolism we need two

important things we need sufficient

cardiac output which means that the

heart is working well enough to

distribute the blood to all the cells in

the body and we need sufficient oxygen

within the blood as well we'll be

talking more about those terms cardiac

output and stuff a little bit later but

for now what I want you to understand is

that what we do is we use blood pressure

as a sorate marker for how good the

blood flow is to all the cells in the

body so what we're saying is if there is

a good blood pressure then we can assume

that there is good profusion of all the

cells in the body body again we're using

the blood pressure as a surrogate for

blood flow which brings us back to our

myth and as Studies have shown there is

only a weak correlation between a baby's

blood pressure and blood flow in the

body this is especially true in the

first 24 hours of life or immediately

after delivery and for anybody that's

interested this study was done by

measuring the blood flow in the superior

venne Carver or kind of measuring the

amount of blood flow that is coming back

to the heart and then correlating that

with the blood pressure so what this

means is we could have a normal blood

pressure but in reality there's a really

low blood flow or we could have a low

blood pressure but really we have enough

blood flow to all the cells in the body

little caveat here obviously if a baby's

blood pressure is super low like it's in

the teens and like a 35 weer then at

that point the chances of having

adequate blood flow is basically zero so

if it's really really low then yes we're

not going to have good blood flow which

again brings us back to our myth so just

because there is a low blood pressure it

doesn't mean we have a low blood flow so

what we need to do is look for other

markers of low blood flow in addition to

the blood pressure so what are the

markers well let's start with if the

baby is pale and has poor perfusion so

think about it if the baby doesn't have

enough blood going to all the cells in

the body it's definitely going to try to

shunt that blood towards essential

organs so towards the heart and the

Brain the skin isn't really an essential

organ so less blood will be going to the

skin and so the baby will appear pale

and there'll be decreased perfusion so

you'll have a delayed capillary refill

so like a 3 to 4 second cap refill time

also the kidneys aren't essential for

second to Second survival so again the

blood would also be diverted away from

the kidneys and how would you know that

this is happening because there would be

decreased urine output objectively

decreased urine output would be

considered less than 1 ml per kilo per

hour but really what's more important is

how much the baby is urinating now

compared to how much it was urinating

previously so if the baby was peeing

like 4 MLS per kilo per hour and is now

peeing 1.1 then that's a huge drop off

in urine output then ultimately if the

cells in the different organs aren't

receiving the oxygen they need then how

are those cells going to metabolize yep

Anor robic and what do the cells produce

when they metabolize anerobic

lactic acid so seeing an increase in

lactic acid is also further proof that

all the cells in the body aren't getting

the oxygen they receive so for example

if you measure the lactic acid and it's

above two or above between 2 to four

milles per liter then this is a sign of

the cells receiving inadequate oxygen if

you're not measuring the lactic acid

then this could also be shown by an

increase in metabolic acidosis on the

gases I know you know that I'm just

saying it let's reward that myth blood

pressure may be one indicator of the

baby's oxygenation status other

indicators would be whether the baby is

pale does the baby have delayed

profusion so a delayed cap refill has

the baby's urine out put dropped off and

do we have increased lactic acidosis or

an increasing metabolic acidosis myth

number three the mean blood pressure is

the most important indicator of overall

status now I know that you know that

this isn't true because otherwise why

would we be even measuring or kind of

figuring out the systolic and the

diastolic blood pressures and then

documenting them remember the mean blood

pressure is exactly what it sounds like

it's the average blood pressure that the

baby EXP experiencing so basically it's

the average between the systolic and the

diastolic blood pressures in adults

because our heart beats slower we spend

a lot longer in diast than syy so the

average blood pressure in adults is

closer to the diastolic blood pressure

in babies whose heart rates beat a lot

faster their mean blood pressure is

relatively closer to their systolic

blood pressure the reason why we talk

about mean blood pressure so much and I

think there are probably two reasons

here the first is is that when we are

doing non-invasive blood pressure

monitoring the mean blood pressure is

what's actually really being measured

and then the other systolic and

diastolic are kind of being figured out

so if anything the mean blood pressure

is probably a slightly more accurate

reading and the other big reason is that

we all often use the mean blood pressure

as kind of an acceptable blood pressure

for premature infants so I learned this

and I actually teach it to people as a

pretty good starting point if you're

really concerned about the blood

pressure and that is that the mean blood

pressure should be about the gestational

age of the baby so for example if the

baby is born at 30 weeks and we have a

mean blood pressure of 31 then hopefully

that's okay by the way this number came

from the German neonatal Network where

they looked at about 5,000 babies who

were less than 32 weeks and they found

that if they teased out the number was

that if in the first 24 hours of Life

the mean blood pressure of the baby was

less than the baby's gestational age in

weeks then that baby had an increased

risk for ivh BPD and death and so mean

blood pressure became kind of like a

catchy thing to remember in the unit oh

it has to be the gestational age not

only that but we kind of extrapolated it

so we have a 4 we old X32 weer okay the

mean blood pressure should be 36 but as

you would or suspect the mean blood

pressure doesn't tell the full story

about whether the baby is getting

adequate blood flow it might be a good

starting point but it doesn't tell the

full story and I can give you all an

example that you've all seen so many

times so let's assume that you have a

2-e old x25 we infant with a mean blood

pressure of 28 but when you look at the

systolic and the diastolic the systolic

is 40 and the diastolic is 17 the mean

is okay but what do you think about the

actual systolic and the diastolic or the

pulse pressure that diastolic definitely

sounds low but let's figure out the

pulse pressure and how do we figure out

whether it's wide or not so what we do

is we double the diastolic so 17 * 2 is

34 if the double the diastolic is still

less than the systolic then we consider

this a widened pulse pressure so in this

situation 34 is obviously less than 40

we do have a widened pulse pressure and

it looks very much like we have a very

low diastolic blood pressure in this

baby you may listen to the heart and

hear a really loud murmur so this would

all go with a PDA now with a PDA or a

symptomatic PDA you might have adequate

pumping from the left ventricle but a

lot of that blood may get shunted off

during diast so even though the mean

blood pressure is adequate there might

not be enough blood actually getting to

the body so you might see decreas in

urine output or increasing acidosis

because of a PDA and we've all had these

scenarios before in the niku let's cover

another example and this is directly

from Dr el kash's paper so let's say

that you have a 30-week baby with a mean

blood pressure of 30 again maybe that

appears acceptable but then let's assume

that the systolic blood pressure is 32

and the diastolic blood pressure is 25

if if anything this pulse pressure is

narrow the diastolic blood pressure is

pretty high and the systolic blood

pressure is pretty low what does this

mean this suggests that the heart is

trying to squeeze against higher

pressures and most likely with that low

systolic the heart isn't able to create

the cardiac output that it needs to so

if the heart isn't get getting enough

cardiac output then the cells in the

body are probably not getting the oxygen

that they need so even though the mean

blood pressure appears adequate here it

looks like the heart isn't being able to

pump adequately so let's reward that

myth the mean blood pressure may be one

indicator of adequate blood flow going

to the baby's body but the systolic and

the diastolic blood pressure Also may

give you clues about why that baby is

not getting enough blood flow myth

number four routinely treating low blood

pressures and neonates in improves

outcomes and this is the key part of

everything we do right like why even

measure something and treat it if it's

not going to make any difference in the

outcome so to take an example completely

out of context say we measure the

thyroid level in a baby and we find out

that it's low and so we give thyroid

medications if giving thyroid

medications doesn't really affect how

the baby does in the future we wouldn't

even bother giving thyroid medications

we wouldn't even bother testing the

thyroid because it doesn't make any

difference so this is how we should

think about all of medicine if we find

the low blood pressures and we do

something about it does it actually make

a difference we know from historical

studies that having a very low blood

pressure is not good for outcomes so it

increases the risk of ivh as well as bad

neurodevelopmental outcomes in the

future having very low blood pressures

and babies but the question Still

Remains if the babies do have low blood

pressure whatever we end up calling that

and we treat the low blood pressure do

those babies end up doing better well

you can imagine how hard this study is

to do if you're doing it retrospectively

so you're looking back at charts of

babies that were treated with blood

pressure medications then you would

assume that the babies that ended up

getting the blood pressure medications

versus those that didn't were kind of

sicker anyway so they were more

predisposed to have bad outcomes anyway

so that's very difficult to tease out

whether actually treating the low blood

pressures has helped or not and then

obviously doing that study prospectively

would be very difficult too so say you

had a huge group of premature babies and

then you randomize them to either

receive blood pressure medication for

low blood pressures or not to receive

medication you can imagine all the Hoops

that you'd have to jump through and also

that would be very difficult as the

clinician taking care of the baby when

we've so been trained that low blood

pressures is bad we'd like find it

really hard not to actually act on that

so A very difficult study to do well

amazingly a large group of researchers

as part of the hypertension in premature

infants or hip trial actually did manage

to start this study they enrolled

infants less than 28 weeks and they

defined a low blood pressure like we've

been talking about as a blood pressure

lower than the gestational age if the

babies did have low blood pressure then

they were randomized into two different

groups so in one group the babies were

given a fluid Bolis 10 m per kilo and

then started on dopamine and in the

other group they were given a fluid

bolus and then started on the placebo

which was

D5W and this was all blinded so the

providers didn't know if the babies were

getting dopamine or D5W this graph shows

the baby's blood pressures and you can

see that the babies that actually

received dopamine did have slightly

higher blood pressures which is nice at

least dopamine mean works I guess you

can say the primary outcome of the study

was survival without severe brain injury

on ultrasound and this was actually

slightly more common in the placebo

group so 69% versus in the dopamine

group 62% mortality was the same in the

two groups as was BPD neck and pvl so if

you just look at this data you might be

thinking well maybe we shouldn't really

be starting dopamine at all and these

babies with low blood pressures

unfortunately though this study was very

underpowered and they only ended up

recruiting about 8% of the babies that

they wanted to for lots and lots of

reasons but really because there aren't

that many pre-term babies and they

required that the preey babies all had

invasive blood pressure monitoring as

well so it was very difficult to recruit

babies also there were a lot of babies

that if they did end up showing signs of

decreased profusion so for example if

they had a lactate of more than four

then the clinicians could go ahead and

use other blood pressure medications to

try to improve those babies blood flow

so there was kind of a bit of crossover

between these two groups anyway because

a lot of the babies in the placebo group

did receive extra medications for their

blood pressures so let's reward that

myth treating a low blood pressure when

it's being shown that the cells have

inadequate oxygen for metabolism so for

example with High lactic acid or

whatever is more likely to affect

outcome than when we just treat the

blood pressure alone that was really

wordy right that brings us to the end of

our first four myths about blood

pressure if you have reached this far

then please like this video tell us

where you're watching from and also will

you tell us which vasoactive agents you

use in your niku I just want to say one

more time thank you so much for being

here