Does methylene blue administration to septic shock patients affect vascular permeability and blood volume?
OBJECTIVE
To assess the effects of the inhibition of guanylate cyclase, an enzyme involved in sepsis-related vascular and myocardial dysfunctions, on hemodynamic variables including blood volume and pulmonary vascular permeability during septic shock.


METHODS
Prospective, open study with repeated measurements.


METHODS
A medicosurgical intensive care unit of a university hospital.


METHODS
Fifteen patients with septic shock associated with persisting hypotension despite conventional treatment including fluid loading, vasopressors, and inotropes.


METHODS
A fiberoptic catheter was inserted for the determination of blood and extravascular volumes by the thermal-dye double indicator technique, using indocyanine green (COLD system). A bolus dose of methylene blue (3 mg/kg) was infused intravenously over 10 mins. COLD-derived variables were recorded before methylene blue and 20 mins, 1 hr, and 2 hrs after the end of methylene blue infusion.


RESULTS
Standard hemodynamic and oxygen-derived variables; total, intrathoracic, systolic, and diastolic cardiac blood volumes; extravascular lung water; plasma osmolarity; and lactate and protein concentrations were recorded. Mean arterial and pulmonary artery pressures, systemic and pulmonary vascular resistances, and left ventricular stroke work index increased, and blood lactate transiently decreased after methylene blue (p <.05). The other variables recorded were unchanged during the 2-hr period following methylene blue infusion.


CONCLUSIONS
This study confirmed the acute vasoconstrictive and positive inotropic effects of methylene blue during septic shock. These effects were not associated with changes in blood volume, myocardial diastolic function, or pulmonary vascular permeability assessed by extravascular lung water.
Donati
Abele
A
Department of Medicosurgical Emergency, University of Ancona, Italy. donati@indi.it
Conti
Giovanna
G
Loggi
Silvia
S
Münch
Cristopher
C
Coltrinari
Rosanna
R
Pelaia
Paolo
P
Pietropaoli
Paolo
P
Preiser
Jean-Charles
JC
D000328:Adult; D000368:Aged; D001810:Blood Volume / Q000187:drug effects*; D002199:Capillary Permeability / Q000187:drug effects*; D002316:Cardiotonic Agents / Q000008:administration & dosage; D004791:Enzyme Inhibitors / Q000008:administration & dosage*; D005260:Female; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors*; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007208:Indocyanine Green; D007262:Infusions, Intravenous; D019344:Lactic Acid / Q000097:blood; D008297:Male; D008751:Methylene Blue / Q000008:administration & dosage*; D008875:Middle Aged; D011446:Prospective Studies; D011652:Pulmonary Circulation / Q000187:drug effects; D012772:Shock, Septic / Q000097:blood / Q000188:drug therapy / Q000503:physiopathology*; D013815:Thermodilution; D014662:Vasoconstrictor Agents / Q000008:administration & dosage
D002316:Cardiotonic Agents; D004791:Enzyme Inhibitors; D014662:Vasoconstrictor Agents; D019344:Lactic Acid; D006162:Guanylate Cyclase; D007208:Indocyanine Green; D008751:Methylene Blue