Invasive and metabolic hemodynamic
monitoring
Invasive monitoring with the Swan-Ganz catheter
allows the differential diagnosis with other situations of low
output and, mainly, a fast and precise evaluation of the
therapeutic maneuvers adopted.
Use of vasodilators and diuretics in high doses in a
patient with AMI may cause low output symptoms with low
filling pressures. Some patients initially diagnosed as
having cardiogenic shock respond to volume reposition,
characterizing the condition of hypovolemia. Clinical and
hemodynamic evaluation allow the distinction of patients
according to the Killip-Kimball heart failure classification 20
and Forrester et al 24, which has therapeutic and prognostic
implications (tab. II).
The determination of the gastric intramucosal pH (pHi)
(or, more appropriately, pCO2 gap) by gastrointestinal
tonometer allows a regional evaluation of the adequacy of
tissular oxygenation and detection of mucosal ischemia,
before the development of ischemic lesions of magnitude
sufficient to allow the translocation of enteric bacteria and
their toxins 25. This sequence of events triggered by a
selective reduction in the oxygen transportation to the
splanchnic organs in shock situations tends to prioritize the
“vital organs”, the heart and brain. Many patients with cardiogenic
shock, after improvement and recovery of cardiac
performance, may have evidence of compromise of the
splanchnic region due to the prolonged hypoperfusion.
Mesenteric ischemia, allowing bacterial translocation,
enhances the morbid process by promoting further reduction
in oxygen transportation, either through hypovolemia,
myocardial depression, hypoxemia, increase in metabolic
demand, or by stressing the inadequate distribution of the
flow, resulting in impairment of the tissue capacity of O2
extraction. Establishment of a normal pHi (7.32) (i.e., a proper
pCO2 gap) as an objective in the resuscitation of patients in
shock may contribute to adequate further blood volume
replacements or alterations in vasoactive drugs 25.
The administration of inotropic drugs such as dobutamine
has been used to optimize O2 transportation. There
is recent evidence that doses much higher than the usual
ones are required to reverse intramucosal ischemia. Tonometry
may help in the titration of these drugs. In some circumstances,
accentuation of intramucosal acidosis was
shown with dobutamine infusion, probably due to flow redistribution
to other areas than the splanchnic ones
Invasive and metabolic hemodynamicmonitoringInvasive monitoring with the Swan-Ganz catheterallows the differential diagnosis with other situations of lowoutput and, mainly, a fast and precise evaluation of thetherapeutic maneuvers adopted.Use of vasodilators and diuretics in high doses in apatient with AMI may cause low output symptoms with lowfilling pressures. Some patients initially diagnosed ashaving cardiogenic shock respond to volume reposition,characterizing the condition of hypovolemia. Clinical andhemodynamic evaluation allow the distinction of patientsaccording to the Killip-Kimball heart failure classification 20and Forrester et al 24, which has therapeutic and prognosticimplications (tab. II).The determination of the gastric intramucosal pH (pHi)(or, more appropriately, pCO2 gap) by gastrointestinaltonometer allows a regional evaluation of the adequacy oftissular oxygenation and detection of mucosal ischemia,before the development of ischemic lesions of magnitudesufficient to allow the translocation of enteric bacteria andtheir toxins 25. This sequence of events triggered by aselective reduction in the oxygen transportation to thesplanchnic organs in shock situations tends to prioritize the“vital organs”, the heart and brain. Many patients with cardiogenicshock, after improvement and recovery of cardiacperformance, may have evidence of compromise of thesplanchnic region due to the prolonged hypoperfusion.Mesenteric ischemia, allowing bacterial translocation,enhances the morbid process by promoting further reductionin oxygen transportation, either through hypovolemia,myocardial depression, hypoxemia, increase in metabolicdemand, or by stressing the inadequate distribution of theflow, resulting in impairment of the tissue capacity of O2extraction. Establishment of a normal pHi (7.32) (i.e., a properpCO2 gap) as an objective in the resuscitation of patients inshock may contribute to adequate further blood volumereplacements or alterations in vasoactive drugs 25.The administration of inotropic drugs such as dobutaminehas been used to optimize O2 transportation. Thereis recent evidence that doses much higher than the usualones are required to reverse intramucosal ischemia. Tonometrymay help in the titration of these drugs. In some circumstances,accentuation of intramucosal acidosis wasshown with dobutamine infusion, probably due to flow redistributionto other areas than the splanchnic ones
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