الفهرس 
Major Physiological Functions of the LiverOnly 14 pages are availabe for public view
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Abstract
End-stage liver disease is caused by variety of chronic
diseases such as viral hepatitis, biliary cirrhosis,
metabolic diseases, alcoholic liver cirrhosis and fulminant
hepatic failure. Patients with liver disease will suffer from
disturbances in the metabolic, hematological and homeostatic
functions as well as portal hypertension and hepatic
encephalopathy.
The poor clinical conditions associated with end-stage
cirrhosis, pre-existing pulmonary abnormalities and high comorbidity rate in patients with high Model for End-Stage Liver
Disease scores (MELD) are all well-recognized factors that
increase the risk of pulmonary complications, preoperative and
post-orthotopic liver transplantation (OLT). Many intra- and
post-operative events, such as fluid overload, massive
transfusion of blood products, hemodynamic instability,
unexpected coagulation abnormalities, renal dysfunction and
serious adverse effects of reperfusion syndrome, are other
factors that predispose patients to postoperative respiratory
disorders. However, despite advances in surgical techniques and
anesthetic management, the lung may still suffer throughout the
perioperative period from various types of injury and ventilatory
impairment, which affects the duration of mechanical ventilation
and weaning.Historically, all patients undergoing liver transplantation
were routinely put on mechanical ventilation for 72 hours.
However, many clinical trials have been done to determine the
most useful and effective ventilatory strategy for the post OLT
patients.
Recently, different ventilatory strategies including
different modes of mechanical ventilation for post OLT
patients have proved their efficacy in many clinical trials.
fast tracking is considered the most favorable approach with
the least complications, better outcomes and lesser ICU
duration of stay. Fast tracking decision depends upon the
preoperative state of the patient, MELD score, pre-exiting
pulmonary disorders, anesthesia, operation procedure and
intra operative IV fluid homeostasis.
The non-invasive mechanical ventilation (NIMV) is
considered an effective weaning mode for the patients who
require prolonged mechanical ventilation and have difficult
weaning process with better outcome than the invasive
mechanical ventilation.
However, the most effective weaning approach is the
daily spontaneous breathing trials, to assist the ability of the
patient to initiate spontaneous breathing independent of
mechanical ventilation before proceeding to extubation. If
failed, other approaches including intermittent mechanical ventilation, NIMV and T- piece ventilation can be applied,
together with the management of ventilator associated
conditions and complications which can affect the weaning
process and prolong mechanical ventilation.
Prolonged mechanical ventilation can increase the risk of
ventilator associated complications, including ventilator
associated pneumonia (VAP), hepatic congestion, graft
dysfunction, respiratory muscle weakness and fatigue,
endocrinal and cardiovascular complications. All these could
increase the mortality rate and could be associated with difficult
weaning.
Ventilator associated complications can minimized and
prevented by choosing the proper ventilatory strategy
according to the patient. Moreover, the use of ―Ventilator
bundles‖ has been shown to decrease complications
including VAP and improve the outcomes that include main
four items: peptic ulcer prophylaxis, deep venous thrombosis
prophylaxis, elevation of the head of the bed to at least 30°
and the use of daily sedation. In addition, daily screening for
early detection and management of any ventilator associated
problems is important for improvement of the mortality and
morbidity of the patient.