The investigators hypothesize that dobutamine is able to revert negative redistribution of flow by inducing a selective vasodilatory effect on hypoperfused territories, particularly at the sublingual and gastric mucosa, and at the peripheral tissues. The investigators designed a randomized, cross-over, placebo-controlled study looking at the acute physiologic effects of 5 mcg/kg/min fixed-dose of dobutamine on cardiac function, microcirculation, gastric mucosal, hepatosplanchnic, and peripheral perfusion in septic shock patients.
The investigators hypothesize that dobutamine is able to revert negative redistribution of flow by inducing a selective vasodilatory effect on hypoperfused territories, particularly at the sublingual and gastric mucosa, and at the peripheral tissues. Therefore, dobutamine improves microcirculatory alterations and regional perfusion in septic shock, independent of its effects on cardiac output. The relevance of this concept is that it would support a more rational use of dobutamine in septic shock patients, not only as an inotrope to increase cardiac output, but more important, as a selective vasodilator aimed at restoring perfusion. Therefore, the investigators designed a randomized, cross-over, placebo-controlled study looking at the acute physiologic effects of 5 mcg/kg/min fixed-dose of dobutamine on cardiac function, microcirculation, gastric mucosal, hepatosplanchnic, and peripheral perfusion in septic shock patients.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
20
Dobutamine at 5 mcg/kg/min will be administered for 2.5 hours each. Measurements will be performed at baseline (within 30 minutes before starting the infusion) and repeated within the last 30 minutes of drug infusion.
A 5% dextrose solution will be administered for 2.5 hours. Measurements will be performed at baseline (within 30 minutes before starting the infusion) and repeated within the last 30 minutes of drug infusion.
Hospital Clinico Universidad Catolica de Chile
Santiago, RM, Chile
Change in the perfused vascular density
Perfused vessel density is a measure of sublingual microcirculation. It will be assessed with SDF videomicroscopy (Microscan ® for NTSC, Microvision Medical, Amsterdam, NL). (Crit Care 2007; 11:R101).
Time frame: 2.5 h
Macrohemodynamics
Macrohemodynamic values: mean arterial pressure, heart rate, and pulmonary artery catheter derived values (pulmonary artery occlusion pressure, cardiac index, systemic vascular resistance index)
Time frame: 2.5 h
Transthoracic echocardiography
1. Morphology and diameters of cardiac cavities 2. Left ventricular systolic function 3. Right ventricular systolic function 4. left ventricular diastolic function
Time frame: 2.5 h
Gastric mucosal perfusion
Gastric mucosal perfusion: gastric air tonometry will be used to measure intraluminal pCO2 and calculate gastric - arterial pCO2 gradient (Tonocap, Datex)
Time frame: 2.5 h
Hepatosplanchnic blood flow
This will be assessed by the ICG-PDR method. Each patient will receive an ICG finger clip which will be connected to a liver function monitor (LiMon Pulsion Medical Systems, Germany).
Time frame: 2.5 h
Peripheral perfusion
1. Peripheral flow index (PFI), derived from the pulse oxymetry signal (MP20 IntelliVue monitor, Philips Medical systems, Amsterdam,NL) 2. Temperatures at the blood (by PAC), and at different places in the skin. We will calculate central to toe gradient (Tc-toe), and forearm to fingertip skin temperature gradient (Tskin-diff) 3. NIRS: Tissue oxygen saturation (StO2) will be measured by a tissue spectrometer (InSpectra Model 325, Hutchinson Technology, Hutchinson, Minn.)
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.
Time frame: 2.5 h
Metabolic perfusion assessment
We will measure mixed venous O2 saturation and arterial lactate
Time frame: 2.5 h