Page 125 - JSOM Summer 2022

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pediatric populations were excluded. While the new criteria Cardiovascular
Sequential (Sepsis-Related) Organ Failure Assessment (SOFA) Decreased intravascular volume is the most frequent cause
was published for the adult patient, there is a lack of recent of shock onset in pediatrics, but in neonates and young in-
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data-driven pediatric sepsis criteria. Many clinicians still use fants, vasoregulation and myocardial function play larger
the 2005 criteria to define pediatric sepsis. Within these cri- roles. 4,13,15,16 For neonates and young infants, left ventricu-
teria and within in every category included, laboratory tests lar systolic performance is dependent on afterload, and an
are required to make an official diagnosis. Diagnosis of se- increase in afterload due to peripheral vasoconstriction can
vere sepsis and septic shock also require additional tests often cause left ventricular dysfunction. 4,17 In adults, an increase in
1,5
only available in resource-rich environments. The absence of afterload can be compensated for by increasing the strength
these capabilities makes it difficult to make a definitive sepsis of contraction due to a more developed left ventricular wall.
diagnosis when such laboratory resources are not available. In young children, the heart is immature, and the left ventricle
Given the complexity of pediatric patients, this information lacks mass proportion, meaning afterload cannot be mitigated
must be kept in mind as clinicians perform their assessments the same way. The younger a patient is, the more contrac-
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and face the unique challenges in austere environments. tile the heart will be at baseline. Neonates and pediatrics alike
rely on increased heart rate to produce the necessary cardiac
output required while distressed. 4,16 Given that the heart relies
Qualifying an Austere Environment
on diastole to perfuse itself, which itself is inverse to the heart
When applying the word austere, defined as “having no com- rate, cardiac filling decreases as the heart beats faster. Eventu-
forts or luxuries; harsh or ascetic,” to a patient care environ- ally, the heart will no longer be able to compensate effectively
ment, we can assume that only basic measures for treatment without medication introduction therapies. In an early re-
are available and the environment itself is harsh. Basic treat- sponse to sepsis, neonates and pediatrics both tend to present
ment measures are often relative to what clinicians carry into with low cardiac output and high systemic vascular resistance
the field and/or can obtain from the surrounding area. In all (SVR), whereas adults generally present high cardiac output
likelihood, laboratory, pharmacy, and radiology services will and low SVR. Low cardiac output is among the largest risk
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be unavailable. Austere environments also boast a wide array factors for mortality in septic children, found to occur in as
of environmental concerns that clinicians must navigate while many as 50% of cases. Despite this, there is limited data to
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providing treatment. These include a) potential lack of shelter, support the use of inodilators in conjunction with volume ex-
b) temperature extremes, c) clean water shortages, and d) in- pansion to increase cardiac output. 19
consistent power. An additional concern in austere care is the
potential lack of transport options and destinations, as it is of- Respiratory
ten difficult to coordinate not only transport out of the area Children are at a higher risk of respiratory failure in the pres-
but also to definitive care. 9,10 Not every country has a dedicated ence of sepsis compared to adults. As oxygen debt and ac-
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children’s’ hospital, let alone an accessible intensive care re- idosis worsen with sepsis progression, respiratory rate will
source in proximity to the child. Sometimes the best chance an increase to compensate, which is consistent across adults and
ill child will have for survival will require transportation across children. Physiologically compared to adults, children are
hundreds of miles. Care in an austere environment can last more predisposed to respiratory failure due to fewer alveoli
hours to days depending on the circumstances, therefore clini- (less surface area for gas exchange), less elasticity of the al-
cians must have ample foresight when considering treatments. veoli, and immaturity of the chest wall (a softer bone struc-
ture with horizontal ribs creates less natural recoil than an
adults chest wall). 4,13 Due to a more acute increase in work of
Physiologic Considerations
breathing, children develop diaphragmatic fatigue, apnea, and
An essential concept that clinicians working with children critical bradypnea faster than adults. Children are also more
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must understand is that children are not simply smaller hu- prone to ventilation–perfusion mismatching, a leading cause
mans; they are immature humans. In the septic child, physio- of hypoxemia in pediatric sepsis patients. This mismatching
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logic compensation is inherently different compared to adults can be somewhat managed by positioning the patient with the
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due to immature physiology. Differences in intracellular fluid “good-lung” up (nondependent). 4,19
volume, cardiac function, respiratory function, and renal
function contribute to how an ill child acutely presents. Un- Renal
derstanding the physiology behind these clinical indicators is AKI is a common and often severe problem that develops in
essential. septic children. AKI is associated with an 80% mortality rate
in the septic child when multiple organ dysfunction syndrome
Fluid Volume (MODS) is present. Some research has suggested that AKI is
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In neonates and infants, volume loss is directly related to an independent risk factor. The mechanisms of AKI in the pres-
weight loss due to higher extracellular fluid levels compared ence of sepsis are still being studied; however, it is believed that
to an adult. 4,11–13 For example, a 5% weight loss is also a 5% the primary mechanisms do not occur due to changes in renal
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plasma loss. Additionally, a 10% fluid loss in a 7-kg patient blood flow but are instead the result of immunologic, toxico-
would be 700mL. For a pediatric patient, this is severe dehy- logic, and inflammatory factors. 20–22 Clinicians should antici-
dration, whereas for an adult, a 700mL water loss is 1/10th pate renal function changes to indicate sepsis progression and
the amount needed to produce the same level of dehydra- be aware that AKI is often found before developing MODS. 4
tion. 4,12,14,15 Therefore, pediatric patients respond well to vol-
ume expansion and often require aggressive fluid resuscitation
in early sepsis. Ill children are at higher risk of dehydration Physical Assessment
and generally suffer from lack of oral (PO) intake; they will In the absence of vital diagnostic resources, assessment skills
also need additional daily fluid therapy goals based on weight. become paramount. As discussed earlier, even with these

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