Effects of Dobutamine on Microcirculation, Regional and Peripheral Perfusion in Septic Shock Patients

Effects of Dobutamine on Microcirculation, Regional and Peripheral Perfusion in Septic Shock Patients

Effects of Dobutamine on Microcirculation, Regional 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. 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.

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.

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).

Macrohemodynamic values: mean arterial pressure, heart rate, and pulmonary artery catheter derived values (pulmonary artery occlusion pressure, cardiac index, systemic vascular resistance index)

Morphology and diameters of cardiac cavities Left ventricular systolic function Right ventricular systolic function left ventricular diastolic function

Gastric mucosal perfusion: gastric air tonometry will be used to measure intraluminal pCO2 and calculate gastric - arterial pCO2 gradient (Tonocap, Datex)

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).

Peripheral flow index (PFI), derived from the pulse oxymetry signal (MP20 IntelliVue monitor, Philips Medical systems, Amsterdam,NL) 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) NIRS: Tissue oxygen saturation (StO2) will be measured by a tissue spectrometer (InSpectra Model 325, Hutchinson Technology, Hutchinson, Minn.)

Inclusion Criteria: Adult patients (>18 years) Septic shock for less than 24 hours Arterial lactate > 2.4 mmol/l Mechanical ventilation and pulmonary artery catheter in place Exclusion Criteria: Pregnancy Refractory hypotension Acute coronary syndrome within the last 3 months Previous use of dobutamine during the last 72 hours Cardiac index < 2.5 l/min/m2 Non-sinus rhythm Heart rate >140 BPM Anticipated surgery or dialytic procedure during the study period Child B or C liver cirrhosis Hemoglobin < 8 gr/dl Uncontrollable fever > 39ºC

Hernandez G, Regueira T, Bruhn A, Castro R, Rovegno M, Fuentealba A, Veas E, Berrutti D, Florez J, Kattan E, Martin C, Ince C. Relationship of systemic, hepatosplanchnic, and microcirculatory perfusion parameters with 6-hour lactate clearance in hyperdynamic septic shock patients: an acute, clinical-physiological, pilot study. Ann Intensive Care. 2012 Oct 15;2(1):44. doi: 10.1186/2110-5820-2-44.