الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 159 |  |  |
| | | from | 159 | | |
Abstract
Patients with acute liver failure develop massive liver damage, which
is progressive in nature and carries high mortality rate. These patients can
only be saved by intensive therapies, including liver transplantation.
Diagnosis of liver failure in children depends on the presence of the first
hepatic insult within 8 weeks with prothrombin time (PT) ≥15-19.9
seconds (s) or international normalized ratio (INR) ≥1.5-1.9 not corrected
by vitamin K in the presence of clinical hepatic encephalopathy, or PT
≥20 s or INR ≥2.0; regardless of the presence or absence of clinical
hepatic encephalopathy.
Acute liver failure is usually associated with hemodynamic
derangements which contribute to multiorgan failure. ALF is
characterized by hyperdynamic circulation with high CO, low MAP, and
low SVR through increased nitric oxide production. Hypovolemia is also
aggravated by poor oral intake of these patients and transudation of fluid
into extracellular space. SIRS – an essential component of ALF – also
plays an important role in the pathogenesis of systemic vasodilation.
Hemodynamic monitoring is an essential part of the management of
the ICU patient. It helps to detect hemodynamic alterations, diagnose
their underlying causes and optimize oxygen delivery to the tissues.
Furthermore, hemodynamic monitoring is necessary to evaluate the
adequacy of therapeutic interventions such as volume expansion or
vasoactive medications. At the bedside, hemodynamic stability and tissue
perfusion are monitored by a combination of clinical examination,
monitoring devices and laboratory results.
Clinical examination should always be an initial step in the
assessment of a critically ill patient ; however it may frequently result in inaccurate assessment of the hemodynamic status. Physical examination
and vital signs alone are unreliable indicators of CO in critical illness that
normalization of vital signs cannot serve as an end-point of resuscitation.
Recent developments include the move from static to dynamic
variables to assess conditions such as cardiac preload and fluid
responsiveness and the transition to less-invasive or even noninvasive
monitoring techniques, at least in the perioperative setting, one of those
recent developed modalities is EC.
Electrical cardiometry has been proposed as a safe, accurate and
reproducible technique for hemodynamic measurement in adults, children
and infants. It is an impedance-based monitoring device that provides
real-time cardiovascular assessment. The changes in electrical bio
impedance is related to aortic flow pattern, and more specifically,
influenced by the alignment of red blood cells in the aorta. The pulsatile
impedance waveform corresponds to the cardiac cycle. Moreover, the rate
of impedance change is used in the calculation of hemodynamic
measures, such as blood velocity, contractility, SV and CO.
Electrical cardiometry is FDA approved. The accuracy and the
clinical utility of EC have been validated against other measures of CO
like direct Fick’s method, thermodilution, and transthoracic and
transesophageal echocardiography in a wide spectrum of patient
conditions and populations across all ages.
In spite EC has been used to monitor hemodynamics in sepsis and
structural heart diseases, it wasn‘t used in pediatrics with ALF.
The aim of this study is to assess the hemodynamics of pediatric
patients with acute liver failure and its relation to the outcome.
According to the exclusion and inclusion criteria, 20 cases
were finally included in the study and subdevided into two
groups, alive group (n=13) and deceased group (n=7).
Inclusion criteria:
Patient age below 18 years.
Biochemical and/or clinical evidence of severe liver dysfunction:
hepatic-based coagulopathy, with a prothrombin time (PT) ≥20s or
international normalized ratio (INR) ≥2., that is not corrected by
parenteral vitamin K and/or hepatic encephalopathy (must be
present if the PT is 15.0–19.9s or INR 1.5–1.9).
Inserting venous central line.
Exclusion criteria:
Patients of acute liver failure and previously known to have any
cardiac, renal or pulmonary disease (could affect hemodynamic
status of the patient).
Data were collected and entered into the computer using Statistical
Package for Social Science (SPSS) program for statistical analysis
(ver 25).
Data were entered as numerical or categorical, as appropriate.
o Data were described using minimum, maximum, mean,
median and 25th - 75th percentile.
Our results showed that:
1. Most of studied patients were males (65%).
2. The median age of the deceased group was higher than the
survived group (d) There was no statistically significant difference of CVP
and capillary refill time between survived and deceased
groups.
(e) Indexed cardiac output measured by EC was compared
between survived and deceased group on admission, at
mid duration of hospital stay, before discharge for
survived patients and before death for the deceased
group. A significant increase in ICO among deceased
group was found before death (p=0.019).
(f) Indexed systemic vascular resistance was found to be
significantly lower in the deceased group before death
than the survived group before discharge.
In conclusion, we believe that EC is a useful objective modality that
can accurately assess the hemodynamics in children with ALF and can at
least be used hand in hand with the clinical assessment and laboratory
investigations to assess hemodynamic status and tissue perfusion.
Finally, we recommend that serial EC measurements can be used to
predict the outcome of children with ALF.